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LECROY 9400A Operating

1. VOLTAGE Cursors button 16 Generates two linear cursor bars which provide accurate differential voltage measurements when adjusted vertically on the currently displayed waveform The REFERENCE and DIFFERENCE controls 38 serve to position the Reference and the Difference cursor bars Voltage cursor bars are displayed as follows ee eee eee ea AEA EI ZU E A TS T yN WR RN LLL NE WT et T Ae A Vey TE T div 2 me Ch 2 20mvV Trig 0Odiv CHAN 1 Main Channel 1 1362 mV DISPLAYED TRACE SHOWING REFERENCE and DIFFERENCE VOLTAGE CURSORS and ALPHANUMERIC READOUT of TRACE AMPLITUDE Figure 5 7 Note that measurement resolution with the VOLTAGE cursors is 0 2 of full scale 8 divisions CURSOR POSITIONING knobs 38 In the case of Time and Voltage cursors the REFERENCE control adjusts the Time and Voltage Reference cursor to the point used as measurement reference The DIFFERENCE control is then adjusted to move the Difference cursor to the desired position along the trace The Marker cursor is moved along the displayed waveform by means of the REFERENCE cursor positioning knob alone Pressing the TRACKING button causes the Difference cursor to track the Reference cursor at a fixed interval as determined by the DIFFERENCE control in the case of Voltage and Time cursors Manual Operation 5 2 1 Menu Controls After the Main Menu key 2 has been pressed any one of the 9
2. Calibrated Vertical Expansion All spectra formats up to 10 times in 1 2 5 sequence Window Functions Selected in menu Rectangular von Hann Hanning Hamming Flattop Blackman Harris and user definable The table below gives filter pass band shape and resolution FILTER PASS BAND AND RESOLUTION Filter band width at Window 6dB type Scallop Noise band Loss width dB at bin freq bins Highest side lobe freq bins dB 1 21 13 3 92 2 00 32 1 42 1 81 43 1 78 1 78 44 0 01 Blackman 1 81 67 1 13 Harris EXECUTION TIME Sec e LB FFT Definitions Filter bandwidth at 6dB characterizes the frequency resolution of the filter Highest side lobe indicates the reduction in leakage of signal components into neighboring frequency bins Scallop loss gives amplitude accuracy of the magnitude spectrum Noise bandwidth is the bandwidth of an equivalent rectangular filter FFT EXECUTION TIME FFT execution times including window calculations and display generation are provided in the graph B AL EHH 50 20 o 625 1250 2500 6250 12500 25000 RECORD LENGTH Points WP01 SIGNAL AVERAGING ARITHMETIC PROCESSING Prerequisite for WP02 Summation averaging 10 1 000 000 signals Continuous averaging infinite number of signals weighting factors 1 3 7 15 63 31 127 Waveform arithmetic Wavefor
3. Controller PC01 programmable controller with LCD display and full size keyboard Medium 720 kilobyte 3 1 2 inch flexible diskettes Bus transfer rate 220 kilobytes sec over National Instru ments GPIB interface model 80400 50 Dimensions 6 9 x 31 2 x 40 5 cm 2 7 x 12 3 x 15 9 inches Weight 6 kg 13 Ibs For further information refer to the mass storage data sheet CALIBRATION SOFTWARE AND SYSTEMS 9400CS01 CALSOFT Test and calibration software poviding a convenient and un B sone tevin A lap top IBM PCC is used to provide mass storage and remote control 9400AMS01 for field and automated testing applications Chi Smy S T div Sys Ch2 50mv gt Trig OOV EXT Freq 1 02 MHz An apparent noise signal top trace is averaged over 400 times middle to reveal a low amplitude clock signal FFT analysis lower shows the clock frequency to be 1 02 MHz ambiguous check of the 9400A s specifications If instru ments traceable to a standard are used the calibration will be traceable to the same standard Computer required Any computer compatible with the IBM PC standard Tests A comprehensive series of tests include internal bandwidth linearity noise rise time overshoot sinefit time base and trigger Presentation of results Results of the calibration check are fully documented on hard copy or can be archived on hard disk or diskette CALSOFT systems Various sy
4. Binary Format of Waveform Descriptors The waveform descriptor contains all information needed to correctly interpret the waveform data In addition there are some values that apply only to some records in particular to waveforms that are the result of data processing The descriptor contains 8 bit values 16 bit values and 32 bit integer values There are no floating point values Multi byte values are always transferred with the most significant byte first In the following list each parameter is identified by its decimal address relative to the beginning of the descriptor and by the number of bits Data values shown are always in decimal Note The first 4 bytes are header information in agreement with IEEE 488 specifications The 5th byte is POS 0 Remote Operations 7 43 Pos Size 8 bit 8 bit 16 bit 16 bit 8 bit 8 bit 8 bit 8 bit Meaning Fixed vertical gain coded as an integer 22 5 mV div 23 10 mV div 24 20 mV div 25 50 mV div RR E E E 31 5 V div Values below 22 and above 31 may occur on processed data records See Section 7 10 1 for an example of how data values are converted to volts in processed data records Variable vertical gain in units of 0 005 of unity 0 gain of 0 4 120 gain of 1 000 See Section 7 10 1 for an example of how data values are converted to volts in processed data records Unused Vertical offset in units of 0 04 of the vertical deflection fact
5. gue Block lt TRAILER gt lt END gt e mH Last Block lt TRAILER gt lt END gt END block lt TRAILER gt lt END gt Where the END block is I When reading data from the 9400A the exact form of the TRAILER is determined by the command COMM TRAILER lt END gt is lt END gt lt CR gt when using RS 232 C unless modified with the command RS CONF EOI ACCOMPANYING the last character of TRAILER when in GPIB If the 9400A receives another command message terminated with lt END gt while sending data the transfer is aborted and status byte 6 ERROR is set to the value 1 Data may be lost if the readout sequence is interrupted with a Serial Poll or by the untalk command Remote Operations 7 6 7 6 1 Commands Notation In this section the following notation is used to explain the commands However these symbols must not be sent to the 9400A as part of a command to denotes the range of a numerical value lt gt denotes the choice of parameters The options are listed vertically denotes the abridged format of a keyword denotes a separator which may be lt gt or a space or lt gt The last two are only acceptable between the header and the first parameter not between parameters x indicates commands which can be executed in REMOTE only Queries terminated with a lt gt are always allowed kx indicates commands which can only be executed in REMOT
6. 25000 20 0 sec 8 0 msec e 25000 50 0 sec 20 0 msec oe 25000 100 0 sec 40 0 msec _ 25000 Note When the 9400A is remotely read out the entire memory content of 32 000 words is available at all time base speeds for single shot and roll modes 24 000 samples are available for all RIS settings except at 1 and 2 wsec div when 24 800 and 25 000 samples respectively are available LIST of SAMPLING MODES SAMPLING RATE and DISPLAYED RECORD LENGTH Table 5 1 Trigger EXTERNAL Trigger Input 24 This BNC connector input accepts an external trigger signal of up to 250 V DC peak AC Input impedance is 1 MQ in parallel with lt 30 pF The triggering frequency is gt 200 MHz Trigger SOURCE 23 Selects the trigger signal source as follows CHAN 1 Selects the Channel 1 input signal CHAN 2 Selects the Channel 2 input signal LINE Selects the line voltage powering the oscilloscope in order to provide a stable display of signals synchronous with the power line Manual Operation 5 6 EXT With the Trigger SOURCE set to EXT a signal applied to the BNC connector labeled EXTERNAL can be used to trigger the scope within a range of 2 V EXT 10 With the Trigger SOURCE set to EXT 10 a signal applied to the BNC connector labeled EXTERNAL can be used to trigger the scope within a range of 20 V Trigger COUPLING 30 Selects the type of signal coupling to the trigger circuit AC Trigger Signals
7. All the front panel controls are active Reading the 9400A by remote control is possible The status byte masks see MASK command and the communications protocol see COMM command may be written status bytes may be cleared When the 9400A is in REMOTE All the front panel controls are deactivated except the two display intensity controls and the left hand side menu buttons All the remote commands are executed A special command SCREEN exists to deactivate the front panel display intensity controls and allows them to be set remotely Compound Commands One or several commands can be sent to the 9400A in a message ending with lt END gt In GPIB transfers lt END gt is the line which marks the EOI End of Information In this case lt END gt is lt gt lt CR gt or lt LF gt In RS 232 C transfers lt END gt is a user selectable string the default is lt CR gt e Where multiple commands are used to compose a message each command is separated from the following one with a lt gt a lt CR gt or a lt LF gt or with any combination of these characters Example TRIG SLOPE POS TIME DIV 50 NS lt END gt represents 2 commands where lt gt is used to separate them Commands are executed only after lt END gt is received Exceptions to this rule are mentioned later see Section 7 4 6 Command Format Simple commands consist of a header indicating the desired operation The header is usually
8. Ea haa In NORM and AUTO the oscilloscope may be forced to autoncatioally store one or both channels in either memory C or D after the acquisition of each wave form This mode slows down the dieplay repetition rate sinos a storage operation takse os much as 200 me COMMON EXPAND OFF When ON the horizontal position and tine magnifier control knobs aot on both expanded traces A AND B for a simultaneous horizontal scan The vertical gain and position remain individually controlled PLOTTING SPECIAL MODES MENU Figure 5 15 5 2 5 1 Auto store Mode Pressing the Special Modes button 7 while in the Main Menu allows the user to automatically store following acquisition CHAN 1 or CHAN 2 into the unit s two reference memories Pressing the Modify Auto store button 2 allows the user to choose from among the following possible storage modes CHAN 1 into Memory C or D CHAN 2 into Memory C or D or alternatively CHAN 1 into Memory C and CHAN 2 into Memory D Manual Operation 5 25 5 2 52 5 2 6 This is a useful feature for very low repetition rate signals acquired in the NORMAL trigger mode Subsequent display of the selected reference memory provides the user with a lasting waveform display which can be studied long after the originally acquired signal has been erased In the NORMAL trigger mode the CHAN 1 and CHAN 2 displays are automatically erased after a two second interval to warn the user that a proper
9. Notes If the 9400A receives a command to store Channel 1 or 2 while it is acquiring data the execution of the command is delayed until the trigger has arrived Remote Operations 7 22 2 3 4 No message will be displayed on the screen when the operation is performed RECALL REC 1 to 8 4 instructs the 9400A to recall one of 8 front panel configurations stored in non volatile memory The value 8 corresponds to the default setup SETUP SU or SETUP SU The first form permits the complete setup to be read in internal data representation Transmission format depends on the selected forms by the COMM FORMAT command The setup data block corresponds to 257 binary bytes The second form permits setup data to be sent to the 9400A in the same form as they were read from the 9400A This command must be terminated with lt END gt i e it must be the last of a list of commands The data transferred to the 9400A must be contained in a separate block see Section 7 5 Note The serial port parameters can not be transmitted In particular if the transfers are by RS 232 C modification of the serial port parameters by this command would bring about some strange results The 9400A sets the VALUE ADAPTED bit if a data value in the block is incorrect The DEFAULT setup will be used in this case The 9400A sets the INVALID BLOCK ERROR if the received block s is incorrect READ RD lt
10. lt FUNCTION F DATA FF DA N N READ RD lt FUNCTION E TIME FE TI lt FUNCTION F TIME FF TI Vv READ RD lt FUNCTION E FE gt lt Parameter list gt lt FUNCTION F FF gt lt Parameter list gt lt intval gt lt values gt lt addr gt lt sweep gt See Section 7 6 5 for more detailed explanations Additional Values in the Descriptors of Processed Waveforms The waveform descriptor contains all the information needed to correctly interpret the waveform data The parameters which describe the raw data records are explained in Section 7 7 they are still valid for processed waveforms However some additional parameters describe the processing which was applied to obtain the current waveform IMPORTANT The parameters in the following list have NO meaning if the Data Processing byte number 34 of the descriptor record is set to 99 raw data In the following list each parameter is identified by its decimal address relative to the beginning of the descriptor and by the number of bits Data values shown are always in decimal Pos Size Meaning 36 16 bit 256 Power of volts see explanation in Section 10 5 38 16 bit 256 Power of seconds see explanation in Section 10 5 40 63 Reserved 64 8 bit Identity of function waveform 4 E 5 F WPO1 Waveform Processing Option 10 13 65 66 67 68 69 70 74 76 78 80 81 82 98 32 bit 102 32 bit
11. p y P g fgain p y n Ps n fo on fl Wow ott 22 256 17 512 26 256 256 corresponding to 5 mU div corresponding to power of 1 corresponding to power of 0 The resulting vertical scale is thus 5 mV div Such a scale might occur in raw data records in averaging extrema or sums of raw data records corresponding to 100 wU div corresponding to power of 2 corresponding to power of 0 The resulting vertical scale is thus 100 uv div Such a scale would result from the multiplication of two raw data records corresponding to 100 mU div corresponding to power of 1 4 corresponding to power of 0 The resulting vertical scale is thus 100 mV 1 4 div i e one tenth of the fourth root of volts per division Such a scale might result from the double application of the Square root operation on a raw data record corresponding to 50 pU div corresponding to power of 1 corresponding to power of 1 The resulting vertical scale is thus 50 pVsec div This scale might result from an integration over a raw data record The following cases can also occur Both powers may be zero corresponding to a dimensionless record e g resulting from a division of raw data records Powers may be negative e g due to a division of raw data records followed by another division Differentiation also gives negative powers of the time unit WPO1 Waveform Processing Option 10 16 10 6 Index of Topics Paragraph T
12. standard Signal processing The waveform processing op tions extend the applications of the 9400A to high bandwidth signal characterization as well as mathe matical and spectral analysis The routines include averaging summed and continuous smoothing inte gration differentiation square square root full arithmetic FFT spectral analysis and Extrema moni toring Mass storage and remote control A sophisticated mass storage and remote control package is available to assist users involved in automated and computer aided testing Convenient portability for field applica tions is also provided by a lap top computer SINGLE SHOT BANDWIDTH NYQUIST FREQUENCY Vs TIME BASE SETTING 10n 50r 00n 500n Iu x S00 1 TIME BASE SETTING sec div Sp 10 U 50u 100p Single shot bandwidth is a function of sampling rate Long memories enable higher sampling rates at equal time base settings Above the 9400A solid line is compared to oscilloscopes with 1K dotted line and 512 points dashed line of memory At slower time base settings the single shot bandwidth of the 9400A expressed as Nyquist frequency is typically 25 times higher than in oscilloscopes with 1K memory and 50 times higher than in those with only 512 points EHEHEHEH EEEE EA o o a o o o o o SPECIFICATIONS VERTICAL ANALOG SECTION Bandwidth 3 dB 50 Q DC 175 MHz at 10 mV div up to 225 MHz at 1V div
13. 2V in EXT 20V in EXT 10 Rate gt 200 MHz SELF TESTS Auto calibration Performed every 20 minutes or wheneve the gain or time base parameters are changed provides accuracies of DC gain 2 1 optional of full scale Offset 0 5 of full scale 50Q only Time 20 psec RMS During the warming up period auto calibration is carried oL at 1 minute intervals unless the oscilloscope is in single or sequence trigger mode DISPLAY CRT 12 5 x17 5 cm 5 x 7 inches magnetic deflection vec tor graphics system Resolution 1024 x 1024 addressable points Grid Internally generated separate intensity control for gric and waveforms Single and dual grid mode Expansion Dual zoom horizontal expansion operates simu taneously on live stored and processed waveforms expanding up to 100 times Vertical expansion from 0 4 up tc 2 times for non processed waveforms up to 10 times for processed waveforms Screen dump Single or multi pen digital plotters are menu selected The 9400A supports the HP 7400 series as well a the Tektronix 4662 Philips PM 8151 Graphtek WX 4638 6 and compatible models Screen dumps are activated by a front panel push button Cursors Two time cursors give time resolution of 0 2 C full scale for unexpanded traces up to 0 002 for expan ded traces The corresponding frequency information is alse provided Two voltage cursors measure voltage differences to 0 2 of full s
14. 8 bit 8 bit 8 bit 8 bit 8 bit 32 bit 16 bit 16 bit 16 bit 8 bit 8 bit 97 Function type 0 Average 1 Extrema 2 Arithmetic 3 Functions 4 Smoothing Sub function type depending on function type Takes on values between O and n 1 where n is the number of sub functions possible The order is the same as in the sub function lists of Section 10 3 Primary source of this waveform O CHANNEL 1 1 CHANNEL 2 2 Memory C 3 Memory D 4 FUNCTION E Secondary source of this waveform arithmetic only with the same interpretation as the previous byte 67 Continuous averaging weight O 1 1 L 1 3 3 2 1 7 3 1 15 4 1 31 5 1 63 6 1 127 Maximum number of sweeps summed averaging and extrema Multiplication factor 100 Additive constant 100 Maximum number of data points lt maxpts gt in the REDEFINE command Reject summed averaging only 0 Reject off 1 Reject on Dithering summed averaging only 0 No dithering Otherwise approximate number of ADC least significant bits corresponding to the maximum dithering excursion Reserved Actually acquired number of sweeps summed averaging and extrema Number of acquired waveforms with overflows summed averaging WPO1 Waveform Processing Option 10 14 10 5 106 32 bit Number of acquired waveforms with under flows summed averaging 110 32 bit Number of rejected waveforms summed averaging with
15. Basic 9400A Waveform Measurements and Operating Procedures 8 6 If the source for signal expansion shown in the Displayed Trace field V is not X Chan 1 you must redefine the expansion signal source to CHAN 1 see Section 8 3 10 Press EXPAND B 46 in order to expand a second portion segment of CHAN 1 11 Select EXPAND B for display control by pressing the SELECT push button 44 Redefine EXPAND B to be an expansion of channel 1 if necessary 12 Choose the segment of interest by adjusting Horizontal POSITION control 39 The number of the selected segment is displayed in the upper right corner of the Displayed Trace field 13 Position the expanded trace in lower grid by adjusting the vertical POSITION control 40 14 Select EXPAND A for display control 15 Choose another segment of interest 39 II 125 Segment Memory Partitioning To make a sequential recording of 125 single events you need only modify the value displayed in the Segments for SEQNCE line of the Panel Status menu by pressing Modify Segments push button 4 until the value 125 appears in the Segments for SEQNCE line Keeping all other settings as above generate 125 triggers The resulting display shows the same waveform but the number of digitized points per segment has changed from 1024 to 256 Resulting display with 31 segments e Pe Chi gt i Y Menu OFF T div 1 ye Cha EU ny Trig 0O0div CHAN i Figure 8 5 Basic 9400A Waveform
16. CHANNEL 1 DESC C1 DE gt lt CHANNEL 2 DESC C2 DE gt lt MEMORY C DESC MC DE gt lt MEMORY D DESC MD DE gt transfer the descriptor of the indicated waveform from the 9400A to the host computer See Section 7 7 for the format of this data block or Remote Operations READ RD lt CHANNEL 1 DATA C1 DA gt lt Parameter list gt lt CHANNEL 2 DATA C2 DA gt lt MEMORY C DATA MC DA gt lt MEMORY D DATA MD DA gt lt Parameter list gt lt intval gt lt values gt lt addr gt lt sweep gt transfer the data values of the indicated waveform from the 9400A to the host computer An explanation of the optional parameter list is given below or READ RD lt CHANNEL 1 TIME C1 TI lt CHANNEL 2 TIME C2 TI lt MEMORY C TIME MC TI lt MEMORY D TIME MD TI VV NP Vv transfer the trigger time s of the indicated waveform from the 9400A to the host computer See Section 7 8 for the format of this data block or READ RD lt CHANNEL 1 C1 gt lt Parameter list gt lt CHANNEL 2 C2 gt lt MEMORY C MC gt gt lt MEMORY D MD transfer ALL visible data of the indicated waveform from the 9400A to the host computer Data are transferred in the order descriptor data time s lt Parameter list gt lt intval gt lt values gt lt addr gt lt sweep gt lt intval gt 1 to 16000 Interval between data points t
17. Portugal M T Brandao Lta 02 691116 Spain Anadig Ingenieros SA 01 433 24 12 Switzerland LeCroy SA 022 719 21 11 Sweden MSS AB 0764 68100 Taiwan Topward El Inst Ltd 02 601 8801 United Kingdom LeCroy Ltd 0235 33 114 Croy Innovators in Instrumentation LeCROY CORPORATE HEADQUARTERS 700 Chestnut Ridge Road Chestnut Ridge NY 10977 6499 Telephone 914 425 2000 TWX 710 577 2832 Fax 914 425 8967 LeCROY EUROPEAN HEADQUARTERS 2 rue Pr de la Fontaine P O Box 341 1217 Meyrin 1 Geneva Switzerland Telephone 022 719 21 11 Telex 41 90 58 Fax 022 782 39 15 Copyright March 1990 LeCroy is the registered trademark of LeCroy Corporation All rights reserved Information in this publication supersedes all earlier versions Specifications subject to change without notice TDS 011 004 MODEL 9400A PORTABLE DIGITAL OSCILLOSCOPE 175 MHz BANDWIDTH 100 Ms s 5 Gs s DUAL CHANNEL OSCILLOSCOPE High Bandwidth and Precision Long Memories High resolution Display Signal Processing and FFT Mass Storage n Above a function generator signal is averaged 40 times to show the details of a perturbation or averaging improves the signal to noise ratio and increases sensitivity and vertical resolu top trace Bue COMPLETE TEST AND MEASUREMENT SYSTEM The LeCroy 9400A Digital Oscilloscope is a powerful general purp
18. Redefine the Window Type to the Flat Top press the Return button The amplitude of the 1 kHz peak should now be very close to the expected 0 636 V but at the cost of a broader peak and a reduced frequency resolution Increase the time record duration Switch to the slower time base of 2 msec div To repeat the acquisition of input and the spectrum computation push the Single Trigger button Fast Fourier Waveform Processing Option WPO2 V 2 06FT 11 5 11 12 13 14 15 The frequency resolution is now increased the harmonic peaks are further apart but the frequency range is reduced You can use the Marker to check the Nyquist frequency of 25 0 kHz at the right hand edge of the spectrum trace which agrees with the value displayed in the FFT menu Switch to 10 msec div and push the Single Trigger button to further increase the time record duration The Nyquist frequency is now 6 25 kHz so that only the harmonics 1 3 and 5 a approximately 1 3 and 5 kHz fit into the frequency range The 7 harmonic at about 7 kHz has been aliased folded back into the peak visible at 2 6 25 7 5 5 kHz Further aliased harmonics of decreasing amplitude are also visible between the original peaks Redefine the Display Type to Power Spectrum and the Window Type back to Rectangular You now see the harmonics on the logarithmic scale at 10 dB div Look at the broad skirts exhibited by the peaks this is the leakage
19. lt LF gt Each character including lt LF gt will be echoed by the computer Computer sends lt TAB gt 9400A answers 1I lt CR gt lt LF gt T lt CR gt lt LF gt will be echoed by the computer Notice that lt LF gt is used both as the last character of lt END gt message string and as the lt ECHO gt character Character strings except lt ESC gt C string for DEVICE CLEAR and lt ESC gt lt ESC gt lt ESC gt lt ESC gt will be lost if sent between lt TAB gt and lt LF gt In both cases if a service request has been activated the string will be sent only when the trigger character is received Remote Operations 7 41 In both cases DEVICE CLEAR lt ESC gt C resets the RS 232 C remote port to the DEFAULT setting i e ECHO ON full duplex mode with lt CR gt as lt END gt message string Overwrite mode if the output buffer becomes full 2 RS SRQ c O to 127 O to 127 O to 127 3 4 5 6 7 Defines a 3 character service request SRQ string that is sent by the 9400A each time the RQS bit bit 6 of the Main Status Byte STB 1 is set to 1 A null character value 0 terminates the string i e a string of 1 or 2 characters may be defined by setting the rest of the characters to 0 If the first character is set to null value 0 the default string is selected Default is the bell value 7 If half duplex mode is selected the transmission of this string may be delayed until t
20. nou fl 66 8 bit Display Type dBm Power Spectrum dBm Power Density Magnitude Phase Real Part Imaginary Part Ln amp LA NM FR 82 8 bit Window Type rectangular von Hann Hamming Flat Top Blackman Harris P L KM KA l H hH H Of 89 8 bit Zero Suppression 0 1 OFF ON 118 119 16 bit Ratio of the number of data points of the expanded waveform over the number of data points computed FFT Application Hints Some practical suggestions 1 To increase the frequency resolution increase the length of the time domain waveform record i e use a slower time base 2 To increase the frequency range increase the effective sampling frequency i e increase the Transform Size Fast Fourier Waveform Processing Option WPO2 V 2 06FT 11 11 3 With transient signals use the Rectangular window You should adjust the time base and the triggering conditions so that the transient is completely contained in the time domain window i e on the screen 4 For the best amplitude accuracy of isolated spectrum peaks use the Flat Top window 5 For the best reduction of leakage and good detection of small peaks several bins away from a large peak use the Blackman Harris window 6 For moderate improvement of amplitude accuracy and of leakage rejection use the von Hann or Hamming window 7 If your time domain signal is repetitive but noisy preventing you from having a stable trigger you can define
21. pressing these buttons will turn the display of a computed waveform ON or OFF The type of computation may be defined by pressing the REDEFINE button 45 See WPO1 Waveform Processing Option Section 10 CHANNEL 1 2 buttons 49 Turn the display of signals applied to either of the input connectors 21 ON or OFF Recording of data into CHAN 1 and CHAN 2 acquisition memories always occurs simultaneously and irrespective of whether the trace display is ON or OFF Display Control Displayed traces may be modified within certain limits following waveform acquisition The CHAN 1 and CHAN 2 traces are controlled by the VERTICAL and Time Base controls 27 28 32 and 36 37 respectively Manual Operation 5 12 Six traces EXPAND A B 46 MEMORY C D 47 and FUNCTION E F 48 are controlled by the Display Control knobs and buttons 39 45 Only one trace is controllable at a time The identity of the controlled trace is indicated by a rectangular frame around the waveform descriptor in the Displayed Trace field V Whenever more than one of the six traces listed above are currently displayed the frame may be moved to the next trace by pressing the SELECT button 44 Horizontal POSITION knob 39 Horizontally positions an expanded waveform and the intensified region along the source trace This control is activated only after the EXPAND A and or B buttons 46 have been pressed to display the expanded trace The
22. such as standard 2 optional 1 DC accuracy high effective bit count and increased reso lution through signal averaging and dithering With the 9400A signals may be acquired and proces sed simultaneously using Channels 1 and 2 This is particularly useful when looking for common fre quency domain characteristics in both signals or for characterization of networks IMPROVED RESOLUTION The Fast Fourier Transform calculates equally spaced frequency components from DC to the full 9400A bandwidth By lowering the sampling rate it is pos sible to make measurements with 1 milli Hertz resolu tion up to 12 5 Hz Nyquist By increasing the sam pling rate to 5 gigasamples sec 200 psec point in Random Interleaved Sampling mode the widest reso lution becomes 50 MHz and the Nyquist frequency 2 5 GHz comfortably above the highest frequency components recordable by the 9400A thus virtually eliminating aliasing effects VERSATILE WINDOW FUNCTIONS The WP02 FFT software provides a selection of win dow functions designed to minimize leakage and to maximize spectral resolution of single and non cyclic events These include the familiar rectangular or unmodified window typically used for transient events the von Hann Hanning and Hamming windows for continuous signals and in addition Flattop and Blackman Harris windows for more precise amplitude power measurements or strong suppression of side lobes respectively Furtherm
23. the RQS bit is set to 1 and a service request SRQ is generated if it is not already pending The bits associated with the lower status bytes STB 2 to 6 are only set inside STB1 if their masks allow the propagation of the bits to STB1 see description of the individual status bytes below VALUE ADAPTED set if a value associated with a remote control command is out of range and adapted to the closest legal value Bit 1 DIO 2 reserved SOFTKEY PRESSED set if one of the 9 soft keys in REMOTE or if the key CALL TO HOST in LOCAL has been pressed The last key is only active after being setup by the command CALL HOST The identity of the soft key is coded in the SOFTKEY PRESSED status byte STB3 INTERNAL STATE CHANGE set if an internal state within the 9400A has changed The identity of the internal state is recorded in the INTERNAL STATE status byte STB 4 OPERATION COMPLETE set if an operation in the 9400A has been completed The associated OPERATION COMPLETE status byte STB5 contains the information about which operation has been completed ERROR set if an error condition has been detected The error is coded in the associated ERROR status byte STB 6 Remote Operations 7 35 RQS GPIB RQS bit indicating if a service request is pending MESSAGE READY set to indicate that a message is ready for transmission to the remote controller STB 2 This status byte is unused and has no significance However i
24. 0 always corresponds to the data value at the left hand edge of the display screen Although the 9400A always digitizes 32000 points except in interleaved sampling or in SEQNCE mode it is not possible to display all of them on the screen because of the ratio TIME DIV to sampling interval Points which are inaccessible on the screen are always positioned to the LEFT of the display screen and can be read by remote control using negative address values Examples a At 0 5 msec div a sampling interval of 200 nsec is used which covers a total time of 32000 200 nsec 6 4 msec However only 10 x 0 5 msec 5 msec can be shown on the screen Thus only 25000 out of 32000 acquired points are shown The other 7000 points cannot be displayed on the screen but are accessible by remote control with the READ command using negative addresses Sms div left edge of screen 7000 0 25000 displayed record 25000 pts 5ms digitized record 32000pts 6 4ms b At 5 wusec div a sampling interval of 10 nsec is used covering a total time of 32000 10 nsec 320 wsec However only 10 5 psec 50 usec can be shown on the screen at this time base setting Only 5000 out of 32000 acquired points are shown The other 27000 values are not displayed but are accessible by remote control Remote Operations 7 48 5 ps div left edge of screen tS a 27000 0 5000 displayed record 5000pts 50 ms digitized record 3
25. 10 11 lt ESC gt R 7 6 10 9 lt ESC gt T 7 6 10 12 lt ESC gt 7 6 10 5 lt ESC gt 7 6 10 6 RS CONF 7 6 10 1 RS SROQ 7 6 10 2 A 4 B dd i
26. 2500 SS 20 sec 6 250 Hz 6250 SS 50 sec 6 250 Hz 12500 SS 100 sec 12 500 Hz 50 ss 200 msec 12 500 Hz 125 SS 0 5 sec 12 500 Hz 250 SS 1 sec 12 500 Hz 500 ss 2 sec 12 500 Hz 1250 Ss 5 sec 12 500 Hz 2500 SS 10 sec 12 500 Hz 5000 SS 20 sec 12 500 Hz 12500 ss 50 sec 12 500 Hz 25000 SS 100 sec Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 23 Fuyquist Number of SS RIS Time div Points 25 000 Hz 50 SS 100 msec 25 000 Hz 100 SS 200 msec 25 000 Hz 250 Ss 0 5 sec 25 000 Hz 500 SS 1 sec 25 000 Hz 1000 SS 2 sec 25 000 Hz 2500 SS 5 sec 25 000 Hz 5000 ss 10 sec 25 000 Hz 25000 SS 50 sec 62 500 Hz 125 SS 100 msec 62 500 Hz 250 SS 200 msec 62 500 Hz 625 SS 0 5 sec 62 500 Hz 1250 SS 1 sec 62 500 Hz 2500 SS 2 sec 62 500 Hz 6250 SS 5 sec 62 500 Hz 12500 SS 10 sec 62 500 Hz 25000 SS 20 sec 0 125 kHz 50 SS 20 msec 0 125 kHz 125 SS 50 msec 0 125 kHz 250 SS 100 msec 0 125 kHz 500 SS 200 msec 0 125 kHz 1250 SS 0 5 sec 0 125 kHz 2500 SS 1 sec 0 125 kHz 5000 SS 2 sec 0 125 kHz 12500 SS 5 sec 0 125 kHz 25000 SS 10 sec 0 250 kHz 50 SS 10 msec 0 250 kHz 100 SS 20 msec 0 250 kHz 250 SS 50 msec 0 250 kHz 500 SS 100 msec 0 250 kHz 1000 SS 200 msec 0 250 kHz 2500 SS 0 5 sec 0 250 kHz 5000 SS 1 sec 0 250 kHz 25000 SS 5 sec 0 625 kHz 125 SS 10 msec 0 625 kHz 250 Ss 20 msec 0 625 kHz 625 SS 50 msec 0 625 kHz 1250 SS 100 msec 0 625 kHz 2500 SS 200 msec 0 625 kHz 6250 SS 0 5 sec 0 625 kHz 12500 SS 1 sec 0 625 kHz 25000 SS 2 sec Fast F
27. 300 ECHO TRUE RETURN DOS ERROR AND TIMEOUT HANDLER t PRINT 2 Error no ERR GOTO 235 PRINT 2 Timeout TIMER OFF GOTO 235 Basic 9400A Waveform Measurements and Operating Procedures 8 17 8 13 Remote Control Via GPIB Option OPO2 only If the 9400A has been equipped with option OPO02 it is also possible to control the various functions of the 9400A via the General Purpose Interface Bus GPIB Example Set the Time Base to 1 msec This example is given to present the different steps necessary to use a GPIB bus Note that most languages offer high level routines that perform these steps automatically In this example an IBM PC or compatible computer equipped with a National Instrugents GPIB PC2 or PC2A GPIB adapter and National Instruments TRIC program default settings are selected is used Preliminary Hardware Setup 1 Before powering up the 9400A select GPIB operation by setting the thumbwheel address switch 54 to 4 2 Connect a GPIB cable to the 9400A s rear panel GPIB connector 55 and to the GPIB connector of the PC Note that upon system initialization the PC must be at address 0 3 In the Handler default configuration and with the prompt A gt displayed on your PC s CRT enter IBIC lt CR gt upper or lower case letters The following message will be displayed on your CRT National Instruments Interface Bus Interactive Control Program IBIC Rev C 0 Copyright C 1984 National I
28. ABRIDGED PANEL STATUS FIELD Figure 5 1 The VOLTS DIV setting for CHAN 1 and CHAN 2 is displayed along with signal input coupling and various other data in the Abridged Panel Status Field IV see Figure 4 1 It may be modified either manually or via remote control and is immediately updated Whereas acquisition control settings displayed in the Abridged Panel Status Field IV are immediately updated upon manual or remote modifi cations of the VOLTS DIV or TIME DIV settings the control settings in the Displayed Trace field V corresponding to the conditions under which the waveform was stored are updated with every trigger iE i 2 pe 2 ys B TE T divi0re Ch2 Z cx lt y nie SENSITIVITY DATA DISPLAYED in the ABRIDGED PANEL STATUS FIELD and in the DISPLAYED TRACE FIELD Figure 5 2 Manual Operation 5 2 VAR 28 Verniers provide continuously variable sensitivity within the VOLTS DIV settings and extend the maximum vertical sensitivity factor to up to 12 5 V div Variable sensitivity settings are indicated by the gt symbol in the lower portion of the Abridged Front Panel Status field and the calibrated value appears in the Total V div field of the Panel Status menu See Section 5 2 2 Minimum sensitivity is achieved by rotating the vernier counter clockwise VERTICAL OFFSET 32 This control vertically positions the displayed trace The maximum offset is 1 grid height 8 div
29. Avgi s 1262 20 1 Figure 5 13 5 23 V 2 09FT Memory D 50 0 mV Omv DCSOQ OFF 5 me 200 ne 2500 0 Pre 20 0 V EXT 10 DC 7000 26000 SINGLE Manual Operation 5 2 4 The indication in the upper right hand corner of Figures 5 12 5 13 5 14 corresponds to the software version implemented in the scope Storage and Recall of Front Panel Setups Pressing the Store PANEL or Recall PANEL buttons 4 and 5 respectively enables storage or recall of up to seven different front panel acquisition parameter settings Store Recall Panel ane aa ae eee aie a gt Panel 1 STORE gt Panel 2 STORE and RECALL FRONT PANEL SETUP MENUS Figure 5 14 Once you have obtained a satisfactory front panel setup simply call the Store PANEL menu by pressing button 4 then press any one of the buttons 2 through 8 to store this front panel setup where required Press the Return button 10 to go back to the Main Menu and continue normal scope operation Manual Operation 5 24 5 2 5 To recall a previously stored front panel setup press the Recall PANEL button 5 while in the Main Menu A list of the seven stored front panel setups which are available will be displayed Press the button 2 through 8 which corresponds to the desired setup and the front panel settings will automatically be configured according to the acquisition parameters recalled Special Modes 7 SPECIAL MODES AUTO STORE OFF
30. BLOCK ERROR if an error in a block has been detected i e if The preamble is incorrect is not A L or bL The preamble number indicating how many values the block has is greater than the number of values that are allowed SETUP DESCRIPTOR or TIME or greater than the number of values remaining until the end of the sweep buffer DATA The number of received values does not correspond to the number in the preamble In the case of ASCII blocks L format there are characters which are neither separator characters CR or LF nor digits In the case of ASCII blocks a value is greater than 255 BYTE or 8 bits transfer or greater than 65535 WORD or 16 bits transfer Other errors Too many or too few values have been received SETUP DESCRIPTOR or TIME Remote Operations 7 28 a2 2 2242 a 424 482484828 4082882060002 READ CHANNEL 2 32000 Instructs the 9400A to transmit the waveform descriptor data and time s of Channel 2 including all invisible data values on the left hand side of the screen The address 32000 is usually out of range but the 9400A automatically adapts to the closest legal value This complete data record is restored in memory C with the command WRITE MC 32000 5 WRITE WT lt MEMORY C DESC MC DE gt lt MEMORY D DESC MD DE gt X transfer the waveform descriptor from the host computer to the indicated memory location of the 9400A This comman
31. Binary Format of Waveform Descriptors The waveform descriptor contains all information needed to correctly interpret the waveform data In addition there are some values that apply only to some records in particular to waveforms that are the result of data processing The descriptor contains 8 bit values 16 bit values and 32 bit integer values There are no floating point values Multi byte values are always transferred with the most significant byte first In the following list each parameter is identified by its decimal address relative to the beginning of the descriptor and by the number of bits Data values shown are always in decimal Note The first 4 bytes are header information in agreement with IEEE 488 specifications The 5th byte is POS 0 Remote Operations 7 43 Pos Size 8 bit 8 bit 16 bit 16 bit 8 bit 8 bit 8 bit 8 bit Meaning Fixed vertical gain coded as an integer 22 5 mV div 23 10 mV div 24 20 mV div 25 50 mV div Boh scutes 31 5 V div Values below 22 and above 31 may occur on processed data records See Section 7 10 1 for an example of how data values are converted to volts in processed data records Variable vertical gain in units of 0 005 of unity 0 gain of 0 4 120 gain of 1 000 See Section 7 10 1 for an example of how data values are converted to volts in processed data records Unused Vertical offset in units of 0 04 of the vertical deflection facto
32. CONF EOI ACCOMPANYING the last character of TRAILER when in GPIB If the 9400A receives another command message terminated with lt END gt while sending data the transfer is aborted and status byte 6 ERROR is set to the value 1 Data may be lost if the readout sequence is interrupted with a Serial Poll or by the untalk command Remote Operations Thus the overall command sequence and data structure is the same as for queries Sending a new setup block to the 9400A Host sends the command SETUP lt END gt to 9400A Host sends the data blocks to the 9400A Each data block is composed of a preamble the data an optional postscript and lt END gt Here the setup data cannot be directly appended to the setup command but must be separated by lt END gt Several block formats are available for read and write they are distinguished from each other by the preamble The command COMM FORMAT selects the format Format A GPIB only binary format no checksum Preamble Abb where bb is the number of data values that will be sent 2 binary bytes Data One binary byte for each 8 bit value two binary bytes for each 16 bit value Postscript None Format L GPIB or RS 232 C ASCII format Preamble L lt count gt where lt count gt is the number of data values that will be sent Data lt data gt where lt data gt are data values in ASCII Postscript None lt count gt and lt data gt are in the
33. DC 150 MHz at 5 mV div 1 MQ AC lt 10 Hz 100 MHz typical 1 MQ DC DC 100 MHz typical Single shot DC 50 MHz Nyquist Input impedance 1 MQ 50 pF and 50 Q 1 Channels Two standard BNC connector inputs Sensitivity range 5 mV div to 1 V div at 50 Q impedance and 5 mV div to 5 V div at 1 MQ impedance detents at 1 2 5 1 2 5 continuously variable Offset 8 divisions in 0 04 division increments DC accuracy Standard lt 2 optional lt 1 Noise lt 0 45 RMS Bandwidth limiter 3 dB 30 MHz Max input voltage 250 V DC peak AC at 1 MQ 5 V DC 500 mW or 10V peak AC at 50 Q VERTICAL DIGITAL SECTION ADCs One per channel 8 bit flash Conversion rate Up to 100 megasamples sec for transient signals up to 5 gigasamples sec for repetitive signals simul taneously on both channels Aperture uncertainty 10 psec Overall dynamic accuracy typical Sine wave applied to the BNC input for RMS curve fit at 80 full scale The accu racy measurement includes the front end amplifier sample amp hold and ADC Nite ens yquist 1 0 10 0 KTS 100 0 175 0 ratio dB Acquisition memories Channels 1 and 2 Two 32K 8 bit word memories 64K total which can be segmented into 8 15 31 62 125 or 250 blocks Reference memories C and D Two 32K 16 bit word me mories 64K total which can store two acquired and or processed waveforms Function
34. E i digitized points O e wessecce aind oeece O eee sue Fanaa eects TEE E d a eooeenete E i Dd z 7 displayed points L A min compacted display with pees min max algorithm To improve measurement accuracy two expansion functions EXPAND A and EXPAND B are provided to display every digitized point trace When the expansion factor is such that 500 measured points are to be displayed every display point corresponds to a digitized point When the time base requires that less then 500 digitized points fill the screen the 9400A interpolates using straight line segments between the actual points In the example below the compacted trace of a 25000 point waveform is expanded by a factor of 100 with EXPAND A and B to provide maximum time measurement accuracy Under these conditions each expanded trace displays 250 digitized points Every other display point is interpolated and the time measurement accuracy is 1 50000 0 0022 Getting the Most Out of Your 9400A 9 3 9 4 Ch Manu OPP Bt 1 648 ps P 541 12 ide T div dps DZ Way Trig 20 div CHAN 1 Figure 9 3 Auto calibration As described in Section 2 5 the 9400A calibrates its time interpolator relative to the internal 100 MHz crystal controlled clock generator every time the time base is modified by front panel operation or by remote control The vertical gain and offset of an input channel are calibrated by means of a very stable internal 12
35. Measurements and Operating Procedures 8 7 8 5 With 125 segments RS232 SETUP Plotter Merw OFF Ch1 gt 1 Ve Vg T div 1 us Ch2 BOU ny Trig OOdiv CHAN i Figure 8 6 Slow Signal Recording Acquisition of a 1 Hz sine wave signal 1 Connect a 1 Hz signal source to CHAN 2 input connector 21 2 Call the Panel Status menu by pressing push button 2 3 Set CHAN 2 sensitivity to 1 V div 27 4 Adjust CHAN 2 OFFSET to 00 V 32 5 Set 6 Set 7 Set 8 Set 9 Set 10 Set 11 Set CHAN 2 COUPLING 22 to DC 1 MQR the Time Base to 1 sec div 36 the TRIGGER SLOPE to POS 25 the TRIGGER LEVEL to 1 00 div 33 the TRIGGER DELAY to 50 Pre 34 the TRIGGER MODE to NORM 29 the TRIGGER SOURCE to CHAN 2 23 12 Press Return push button 10 to return to the Main Menu 13 Set 14 Set CHAN 1 to OFF and CHAN 2 to ON by pressing push button 49 DUAL GRID mode to OFF 14 Resulting Display A sine wave signal will be displayed rolling from right to left across the screen The display can be halted by pressing the SINGLE push button 29 when in NORMAL trigger mode When in AUTO trigger mode the display is halted upon receipt of an external trigger signal Basic 9400A Waveform Measurements and Operating Procedures 8 8 8 6 8 7 Window Triggering Window triggering allows the user to capture signals exceeding the positive or negative limits set around the base line in interna
36. NW Ln amp L A KA YNNN amp LA DM kA e YNNN d d d d d E E E E E E E E E 0 9 d d Ln E LQ MM pa YN O Ln YN d d d d dl d d d CN CN C C C Ca CN C Ch Cy ES bed d ON 2 2 PO Mn A US WH HF 5 2 Menu Controls Store Menu Panel Status Menu Memory Status Storage and Recall of Front Panel Setups Special Modes Auto store Mode Common Expand Mode RS 232 C Setup Plotter Setup REAR PANEL CONTROLS AND CONNECTORS Fuse Protection Accessory Power Connectors Battery Pack GPIB and RS 232 C Port Selection Plotter Connector OPERATIONS Programmed Control RS 232 C Ports GPIB Port Option OPO2 only GPIB and RS 232 C Command Format Introduction Compound Commands Command Format Answers from the 9400A Flushing of 9400A Output Buffer Command Synchronization with Data Acquisition Character Strings Prompt Errors and Adapted Values Data Block Transfers Commands Notation Acquisition Parameter Commands Display Commands Plotter Commands Transfer Commands Other Remote Commands Communication Format Command Status Byte and Mask Register Commands GPIB Interface Message Interpretation RS 232 C Only Commands iii si Gee Gis A NR KA KA KA Y dl d wN rtf LQ N KA KA l Ll GO d d C Ca Ln E amp LA dl d L 4 p 7 11 7 12 7 15 7 20 7 22 7 30 7 31 7 34 7 38 7 39 7 7 Binary Format of Waveform Descriptors 7 8 Format of Trigger Time s 7 9 Data Addressing
37. ON the bandwidth can be reduced from 175 MHz to 30 MHz 3 dB Bandwidth limiting may be useful in reducing signal and system noise or preventing high frequency aliasing for single shot events at time bases below 50 usec division Time Base TIME DIVISION 36 This control selects the time per division ina 1 2 5 sequence from 2 nsec to 100 sec The time base is displayed in the Abridged Panel Status field IV as well as in the Displayed Trace field V The time base is crystal controlled and features an overall accuracy better than 10 SAMPLING MODES Three sampling modes are possible with the 9400A depending on the time base setting selected by the user They are Random Interleaved Sampling RIS Single Shot SS Roll Mode Random Interleaved Sampling RIS At time base settings from 2 to 20 nsec div the 9400A automatically uses the RIS mode for signal acquisition Repetitive waveforms and a stable trigger are required Waveforms can be digitized with sampling intervals as small as 200 psec for an equivalent sampling rate of up to 5 gigasamples sec Manual Operation 5 4 Between the 50 nsec and 2 usec div range of time base settings the user may select the RIS acquisition mode by pressing the INTERLEAVED SAMPLING button 37 Single Shot For time base settings from 50 nsec to 200 msec div the 9400A records the waveform in a single acquisition Sampling rates up to 100 megasamples sec are possible in the Single
38. Option WP02 V 2 06FT 11 30 J E E EE EE DE EE E E E D O O o a O o eee 8 C APPENDIX Index of remote commands GPIB and RS 232 C This index groups all remote commands described in sections 7 10 and 11 of this manual All commands listed in this index are common to both the GPIB and the RS 232 C interfaces For convenience the commands as well as their abridged forms have been arranged in alphabetical order The number on the right hand side refers to the paragraph section where the command is defined AUTO STORE AS 7 6 6 3 AVERAGE RESET ARST 10 3 1 BANDWIDTH BW 7 6 2 14 CALIBRATE CAL 7 6 6 1 CALL HOST CH 7 6 6 4 CHANNEL 1 ATTENUATION C1AT 7 6 2 11 CHANNEL 2 ATTENUATION C2AT 7 6 2 41 CHANNEL 1 COUPLING C1CP 7 6 2 13 CHANNEL 2 COUPLING C2CP 7 6 2 13 CHANNEL 1 OFFSET C10F 7 6 2 12 CHANNEL 2 OFFSET C20F 7 6 2 12 CHANNEL 1 VOLT DIV C1VD 7 6 2 10 CHANNEL 2 VOLT DIV C2VD 7 6 2 10 COMM BLOCKSIZE CBLS 7 6 7 5 COMM FORMAT CFMT 7 6 7 4 COMM HEADER CHDR 7 6 7 1 COMM HELP CHLP 7 6 7 3 COMM PROMPT CPRM 7 6 7 7 COMM STRDELIM CSDE 7 6 7 6 COMM TRAILER CTRL 7 6 7 2 DUAL GRID DG HOR POSITION HP IDENTIFY ID INSPECT CHANNEL 1 INS CHANNEL 2 INS FUNCTION E INS FUNCTION F INS MEMORY C INS MEMORY D INS INTERLEAVED IL KEY MASK MESSAGE MSG PLOTTER PT PLOT SIZE PS PROBE CAL PC READ CHANNEL 1 RD C1 CHANNEL 2 RD C2 FUNCTION E RD FE FUN
39. Power Spectrum on the dBm scale with 0 dBm corresponding to 0 316 Vpeak Power Density spectrum The Power Density Spectrum V Hz is the Power Spectrum divided by the product of the equivalent noise bandwidth of the filter and the frequency bin width in Hz The 9400A displays the Power Densisy spectrum on the dBm scale with O dBm corresponding to 0 316 naa Hz Sampling Frequency In the 9400A the time domain records are acquired at sampling frequencies which depend on the selected time base consult Table 5 1 Before FFT the time domain record may be sub sampled If the selected number of points is lower than the displayed record length Table 5 1 the total sampling frequency will be reduced The total sampling frequency equals twice the Nyquist frequency displayed in the FFT Redefine Menu Scallop Loss Loss associated with the picket fence effect listed in Table 11 3 for windows implemented Fast Fourier Waveform Processing Option WPO2 V 2 06FT 11 19 Window Functions All window functions implemented in the WPO2 package belong to the sum of cosines family with one to three non zero cosine terms m M 1 2 x n x j k W a cos O lt k lt N k m N m O where M 3 is the maximum number of terms 9 are the coefficients of the terms N is the number of points of the source waveform k is the time index Table 11 2 lists the 9 coefficients The window functions seen in the time domain a
40. Redefine button Note the message COMPUTING in the lower left corner of the screen After 2 seconds the computed Magnitude spectrum is displayed If you are using the Normal or Auto trigger mode you will get a new spectrum about every 1 7 seconds Note the frequency scale factor of 10 kHz div and the frequency range of 6 25 divisions from zero to 62 5 kHz the Nyquist frequency The zero frequency is always displayed at the left hand edge of the screen The frequency interval Af between two computed points equals 1 T where T is the duration of the time domain record 10 msec In this case Af 100 Hz Observe that the signal spectrum has a prominent peak the fundamental harmonic at about 1 kHz followed by the peaks of the odd harmonics of decreasing amplitude Freeze the spectrum by selecting the Single Trigger mode You can use the Marker to check the exact frequency and amplitude of the 1 kHz peak You may use trace expansion A or B to view details of the peaks and to adjust the Marker Note that the step size with which you can advance the Marker is not related to the interval between the computed points The step becomes finer when you increase the expansion factor With the Rectangular Window the amplitude of the 1 kHz peak may be inexact picket fence effect In the example above with 0 50 V peak square wave you would expect 0 50 V 4 n 0 636 V for the first harmonic but you will find about 0 43 V
41. Reject ON L l 114 16 bit Number 1 of data points used in the computation of this data record may be less than lt maxpts gt 116 16 bit Ratio of the number of data points in the source waveform over the number of data points used 118 149 Reserved Vertical Scaling Units With the introduction of waveform processing functions such as multiplication division square root integration and differentiation which alter the vertical scaling units a more general system for the vertical scales must be introduced Three variables are now involved fixed vertical gain is now interpreted slightly differently by dropping the notion of volts Compare with Section 7 7 fgain byte 0 22 5 mU div 23 10 mU div 24 20 mU div 25 50 mU div ees 31 5 U div Where U now stands for a general unit which may bea product of a power of volts and of a power of seconds 256 power of volts 256 power of seconds P V bytes 36 37 P s bytes 38 39 Thus U Volts P_V 256 Seconds P_s 256 NOTE Whenever the WPO1 waveform processing option is installed P_V and P_s are always valid even in raw data records see the following example However in software versions without waveform processing they cannot be relied upon Of course in these cases the vertical scales are always in volts WPO1 Waveform Processing Option 10 15 Examples fgain p yn P s fgain p y n P s 1 fgain
42. Shot mode Roll From 500 msec to 100 sec div the 9400A samples continuously Each digitized point updates the display resulting in a trace moving from right to left similar to that produced by a strip chart recorder TIME BASE SAMPLING RATE DISPLAYED RECORD TIME POINT LENGTH Points TIME DIV RIS Ss RIS ss 2 0 nsec 200 psec 100 5 0 nsec 200 psec 250 10 0 nsec 200 psec 500 20 0 nsec 200 psec 1000 e 50 0 nsec 200 psec 10 0 nsec 2500 50 0 1 usec 200 psec 10 0 nsec 5000 100 0 2 usec 200 psec 10 0 nsec 10000 200 0 5 usec 200 psec 10 0 nsec 24000 500 1 0 usec 400 psec 10 0 nsec 24800 1000 2 0 usec 800 psec 10 0 nsec 25000 2000 5 0 usec 10 0 nsec 5000 10 0 usec e 10 0 nsec 10000 20 0 psec e 10 0 nsec eoa 20000 50 0 usec 20 0 nsec e 25000 0 1 msec 40 0 nsec e 25000 0 2 msec 80 0 nsec e 25000 0 5 msec e 0 2 usec 25000 1 0 msec 0 4 usec 25000 2 0 msec 0 8 usec 25000 5 0 msec 2 0 usec 25000 10 0 msec 4 0 usec 25000 20 0 msec 8 0 usec 25000 50 0 msec 20 0 usec 25000 0 1 sec 40 0 usec 25000 0 2 sec 80 0 usec 25000 Manual Operation 5 5 5 1 3 TIME BASE SAMPLING RATE DISPLAYED RECORD TIME POINT LENGTH Points TIME DIV RIS Ss RIS Ss ROLL MODE 0 5 sec 0 2 msec 25000 1 0 sec 0 4 msec nen 25000 2 0 sec 0 8 msec anu 25000 5 0 sec o 2 0 msec taa 25000 10 0 sec 4 0 msec
43. Type Fourier Transform Display Type Power Spectrum dBm Power Density dBm Magnitude Phase Real Part Imaginary Part Transform size 50 to 25000 Source Trace Channel 1 Channel 2 Memory C Memory D Function E for Function F only Window Type Rectangular von Hann Hanning Hamming Flat Top Blackman Harris Multiplication Factor 0 01 to 9 99 Additive Constant 9 99 to 9 99 Zero Suppression OFF or ON m ee lan e te ee ee ce ee ee ee nnn ee mt ee ee ee es m ee es ees es es i ee es ee ee ees ees ees ees ees ee es ees ee ees ees ees ees ees ee ees ees ees ee ee ae zear ms i ee ee ee ee ce ce ce ee ee ee ee ee ee ee ee ee ee ee re ee ee ee ee ee ees ee ees es es ee ee ee ee ee ees ees ee ee ees es ee ee ee ee P ee Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 1 The 9400A s Function F can also be defined as the Power Average of the FFT computed by Function E Values of the following FFT processing parameters can be selected in the FFT Power Average redefine menu or with remote control commands er Fe d nnn 2r S SE ET g I SE ST SE SSS Ll Ll SS SS SS LS SS SS eS S eS l l eS eS r E E E E SS ne Se aa E SS ee Se a eee Function Type FFT Power Average Display Type Power Spectrum dBm Power Density dBm Magnitude Transform Size Same as Function E Source Trace Function E Max number of sweeps 10 to 200 os s ik iak ee ee ee ee ee es ee Oe ee E eo oe es Ge ee ee ee ee ee ii amp i ee Al
44. a RS 232 C connection since it is not predefined On the 9400A the RS 232 C Service Request consists of 1 to 3 characters followed by the RS 232 C version of lt END gt as defined by the command RS CONF in Section 7 6 10 default is CR sent by the 9400A to the host computer It is the responsibility of the programs on the host computer to recognize them By default they consist of 1 bell character binary value 7 Since transfers over RS 232 C can only be in ASCII the bell character is rather easily recognized as a special message Also the user may redefine the SRQ characters to some other sequence with the command RS SRQ The Serial Poll does not exist on an RS 232 C connection either The only way to get more information about the status of the 9400A or the reasons for an interrupt is to read the value of STB 1 or the other status bytes Of course the user always has the choice of working without any Service Requests by polling the Main Status Byte STB 1 with the command STB 1 See Section 7 6 8 Example MASK 1 40 Sets the mask of the Main Status Byte STB 1 to the binary value 00101000 allowing the ERROR bit or the INTERNAL STATE CHANGE to generate an RQS bit i e to generate a service request MASK 4 6 Sets the mask of the INTERNAL STATE byte STB 4 to the binary value 00000110 i e it demasks the 2 overload bits If an overload occurs the mask now allows the propagation of the bit to the INTERNAL STAT
45. a processed point Y k corresponding to N 1 2 Y k H C n Y k n n N 1 2 where in case of a 3 point filter N 3 C 1 4 C 1 2 C 1 4 The number of points N can be selected to be 3 5 7 or 9 In interleaved sampling mode the averaging speed is reduced as more signals are required to complete a displayed waveform WAVEFORM ARITHMETIC Addition subtraction multiplication and ratio can be _ performed on two live waveforms from CH1 and CH2 or from stored waveforms in memories C D and E Example E CH1 CH2 F CH2 D F CHI E Number of points processed from 50 to 32000 can be selected in 10 steps Multiplicative constants from 0 01 to 9 99 can be selected in steps of 0 01 Additive constant from 9 99 to 9 99 divisions can be selected in steps of 0 01 Vertical expansion 2 times maximum Typical execution time for 1250 points 600 msec WAVEFORM FUNCTIONS Integration differentiation square square root negation invert Examples E CH1 dt F CH2 dD dt Number of points processed from 50 to 32000 can be selected in 10 steps Multiplicative constants from 0 01 to 9 99 can be selected in steps of 0 01 Additive constant from 9 99 divisions to 9 99 divisions can be selected in steps of 0 01 Vertical expansion 2 times maximum Typical execution time for 1250 points 400 1000 msec _ MEAN VALUE SMOOTHING Number of adjacent blocks processed
46. an SRQ However if STB 1 is now read explicitly or by Serial Poll the binary value 10000000 80 in hexadecimal would be read AAA This illegal command generates a syntax error and sets the ERROR byte STB 6 to the value 11 Simultaneously the ERROR bit of STB 1 is set Since this bit is demasked in STB 1 it sets the RQS bit and generates a service request SRQ CALL HOST This command is illegal since the required parameter is missing It generates a semantic error and sets the ERROR byte STB 6 to the value 40 This error should again be propagated to the ERROR bit of STB 1 but it cannot generate a service request since it is still pending Remote Operations 7 54 7 11 2 If the host computer executes a Serial Poll at this moment the binary value 11100000 EO in hexadecimal is read i e the MESSAGE READY bit from the previous command TIME DIV and the ERROR bit RQS bit from the command AAA are set Upon the execution of the Serial Poll these bits are reset Since no DIFFERENT bit capable of setting RQS was generated in the intervening time no more Service Requests are generated If the host computer reads the ERROR byte STB 6 with the command STB 6 it will receive the value 40 corresponding to the second error Thus if several errors occur before the host computer responds only the last error is retained by the 9400A Service Request in RS 232 C The Service Request must be simulated on
47. be configured to work either in full duplex mode or in half duplex mode Full duplex mode may be selected if the host computer does not echo the characters it receives from the 9400A and if it is able to store the received characters in a buffer In half duplex mode the host computer tells the 9400A to talk by sending a trigger character to the 9400A In full duplex mode the 9400A sends its message s immediately Remote Operations 7 39 In half duplex mode after it has received the trigger character and the selected delay has elapsed the 9400A sends its messages one at a time until lt END gt message It needs a trigger for each message If the host echoes received characters echo mode must be selected In that case the 9400A discards any received characters except those of Device Clear Command until it receives the lt echo gt character The 9400A may be configured for Half Duplex mode in two situations a If the computer which controls the 9400A through the RS 232 C Remote port does not support full duplex communication and cannot support data flow between the 9400A and itself in both directions simultaneously e g if the port on the computer can only be open in one direction at a time b If the computer which controls the 9400A echoes characters it receives from the 9400A the port acting as a terminal port In the first case the 9400A can be configured with the following sequence of commands lt ESC gt disable
48. bit digital to analog converter every time the fixed gain control of this channel is modified Calibration of both channels also takes place whenever the bandwidth limit is changed These calibrations are necessary largely because of drifts caused by temperature changes which could arise if the 9400A is left in the same state for a very long time To avoid measurement errors due to potential drifts an internal timer of the 9400A forces a complete auto calibration every minute during the first 10 minutes after power up and every 20 minutes thereafter This operation is transparent to the user but is audible due to relay switching Note that auto calibration does not occur in SINGLE or SEQNCE trigger mode In remote control all auto calibration can be turned off It may be executed whenever requested see the CALIBRATE command in Section 7 6 6 Getting the Most Out of Your 9400A 9 4 10 1 SECTION 10 WPO1 WAVEFORM PROCESSING OPTION Processing Capabilities The NPO Waveform Processing Option includes an _ additional 0 5 megabytes random access memory for accumulation computation and waveform buffers This allows accumulation of averaged waveforms of 32000 data points in 32 bit form All waveform processing occurs through the waveforms E and F which may be displayed on the screen by pressing the corresponding FUNCTION E F 48 push button Whenever the FUNCTION E or F trace or an expansion of one or both of these
49. can be moved beyond the right hand edge of the time domain waveform and thus become Frequency Cursors providing Simultaneous readout of frequency difference and of amplitude difference between two points on each frequency domain trace a ee ce ee t et ee ee ee ee y ee ee ee ee ee es ee ee drs ee ee ee es ee ee ee ee ee ey mt daia pp ee ee ee my ee mr ee ee ee adu ee ee ee ee ee es ee ee ee daia Table 11 1 Display Types Display type Unit Vertical position of zero Power Spectrum dBm mark Power Density spectrum dBm mark Magnitude V 3 div Phase degree O div Real Part V O div Imaginary Part V O div Note Vertical position of 0 dBm varies with the source waveform s gain A mark at the left hand edge of the screen indicates the dBm level of a trace Generally a sinusoidal source waveform of 8 div peak peak will give a spectrum point of about 3 div at any gain ey ee ee re hai ce cr iat ce m ee er ee es zoi ec ce ce re my ee rele ee ce ce y m my ee ee ew te ee dat d Since the computation of FFT may take up to 1 minute for a Transform Size of 25000 points it is possible to interrupt an undesired FFT either by turning off the corresponding trace s or by pushing the Redefine button if the FFT trace is the selected trace Modification to WPO1 Functions With the option WPO2 FFT installed the WPO1 functions are modified as follows When any WPOl function operates ona frequency domain waveform a result of FF
50. can configure the 9400A to generate an interrupt to the host computer upon the occurrence of one or several conditions The user must demask the bit s of the status byte which corresponds to the condition s by setting 1 s into the corresponding bit of the mask in question In addition the corresponding bit in the Main Status Byte STB 1 must also be demasked in order to allow the generation of the Service Request This method is much more efficient timewise but requires a more complex setup In addition the host computer must be configured to handle an interrupt by the GPIB SRQ line See Section 7 11 for more explanations and examples Remote Operations 7 34 Status bytes are cleared except STB 4 when reading them with the command STB but not with TSTB They are also cleared on POWER ON and by a Device Clear command Mask registers are cleared on POWER ON with a Device Clear command or by writing O into them Main Status Byte STB 1 DIO T Bit Associated Significance 1 8 0 7 data byte to generate an SRQ DIO 1 0 none VALUE ADAPTED DIO 2 1 STB 2 unspecified DIO 3 2 STB 3 SOFTKEY PRESSED or CALL TO HOST DIO 4 3 STB 4 INTERNAL STATE has CHANGED DIO 5 4 STB 5 OPERATION COMPLETE DIO 6 5 STB 6 ERROR detected DIO 7 6 none RQS request for service DIO 8 7 none MESSAGE READY If one of the bits DIO 1 to DIO 6 or DIO 8 becomes 1 and the corresponding bit is set in the Main Mask register MASK 1
51. computer terminates the transfer by sending UNT UNTalk and UNL UNListen and setting the 9400A into LOCAL Configuring the Parallel Polling Option OPO2 only Send the following sequence of GPIB commands to the 9400A listen address of the 94004A PPC Parallel Poll Configure PPE Parallel Poll Enable in binary 0110 S P3 P2 Pl Where P3 to P1 represents DIO line number 1 S 1 if 1 must be sent while Service Request is active 0 otherwise UNT UNTalk and UNL UNLlisten non obligatory Basic 9400A Waveform Measurements and Operating Procedures 8 20 To unconfigure the parallel polling send the following sequence of GPIB commands to the 9400A Listen address of the 9400A PPD Parallel Poll Disable in binary 0111S P3 P2 Pl as mentioned above PPU Parallel Poll Unconfigure UNT or UNL non obligatory Other sequences of commands are also possible Basic 9400A Waveform Measurements and Operating Procedures 8 21 9 1 9 2 SECTION 9 GETTING THE MOST OUT OF YOUR 9400A The 9400A is a highly accurate digital oscilloscope which achieves optimum precision when handled properly The purpose of this section is to familiarize the user with operations and functional hints that will ensure the best possible operation of the instrument Front Panel Controls All front panel controls are fully remotely controllable and are therefore constantly monitored by the 9400A s internal processor
52. data points per division is shown in the Acquisition Parameters display called by pressing Panel STATUS button 2 The display is only updated after a sufficient number of sweeps has been acquired If less than the required number of triggers is available the SEQNCE acquisition may be aborted by pushing the SEQNCE button 29 again The 9400A then completes the missing sweeps by auto triggering a sufficient number of times while setting its input coupling temporarily to GND Thus the artificially completed sweeps will appear on the display as GND lines Manual Operation Number of Segments Points Segment 8 2501 15 2001 31 1001 62 497 125 241 250 101 SEQUENCE TRIGGER MODE NUMBER OF SEGMENTS VS RECORD LENGTH TIME BASE 20 usec Table 5 2 Neither the CHAN 1 nor CHAN 2 display is updated when the 9400A is in the SINGLE or SEQNCE trigger mode i e when no further data are acquired Vertical positioning of the displayed trace may nevertheless be modified via the OFFSET control 32 The VAR vernier 28 also remains active However no other parameter modifications such as vertical sensitivity or time changes will alter the display of a currently acquired waveform in CHAN 1 or CHAN 2 Of course all parameters may be modified during this time by manipulating the appropriate front panel controls but such modification indicated by parameter changes in the Abridged Front Panel Status field IV will only be used when acq
53. descriptor block s The 9400A checks the limits of each parameter transmitted If any value is out of range or the number of values transmitted is incorrect the entire descriptor block is considered invalid and is discarded WRITE WT lt MEMORY C DATA MC DA gt lt Param list gt lt MEMORY D DATA MD DA gt lt Parameter list gt lt intval gt lt values gt lt addr gt lt sweep gt transfer data values from the host computer to the indicated memory location of the 9400A This command must be followed by the data value block s See the READ command for an explanation of lt Parameter list gt or WRITE WT lt MEMORY C TIME MC TI gt lt MEMORY D TIME MD TI gt transfer trigger time s from the host computer to the indicated memory location of the 9400A This command must be followed by the trigger time block If the number of values transmitted is incorrect the entire block is discarded When transferring WRITE DATA without specifying the number of data values the nominal number 1 data values must be sent to the 9400A 25000 1 data values for example This additional value may be needed for the generation of the last displayed point at the right hand side of the screen or WRITE WT lt MEMORY C MC gt lt Parameter list gt lt MEMORY D MD gt Remote Operations 7 27 lt Parameter list gt lt intval gt lt values gt lt addr gt lt sw
54. displayed traces When the Time cursors are activated by pressing push button 17 two readings are indicated The left hand reading indicates the time interval between the Reference and Difference arrowhead cursors while the right hand reading indicates the frequency corresponding to 1 Time interval Trigger Delay Field IIT This field indicates one of the two trigger delay modes Ln the pre trigger mode an upward pointing arrow appears below the bottom line of the trace display grid as shown in Figure 4 1 It is adjustable from O to 10 divisions corresponding toa 0 to 1002 pre trigger setting In the post trigger mode this arrow is replaced by a leftward pointing arrow next to the post trigger indication in decimal fractions of a second at the bottom of the grid The maximum post trigger setting corresponds to 10000 screen divisions Abridged Front Panel Status Field IV This is a short form display of the data acquisition parameters and is updated whenever the 9400A s front panel controls are manipulated This field indicates vertical sensitivities input couplings time base and trigger conditions See Section 5 for a detailed list of front panel parameters including the absolute value of input offset Displayed Trace Field V The Displayed Trace field is associated with push buttons 45 50 The data displayed in this field are the identity of the displayed trace and the current time base and sensitivity setting
55. divisions post trigger at any time base setting ensure that rare events cannot be missed Both channels are sampled simultaneously so that exact time correlation is main tained between channels Full programmability All the 9400A s front panel controls are fully programmable via the two RS 232 C interface ports or the GPIB port A single push button initiates a screen dump for accurate color hard copies of the display via a wide range of digital plotters The GPIB comes complete with LeCroy MASP software offering computer control and mass storage on any PC compatible with the IBM standard Signal processing The waveform processing op tions extend the applications of the 9400A to high bandwidth signal characterization as well as mathe matical and spectral analysis The routines include averaging summed and continuous smoothing inte gration differentiation square square root full arithmetic FFT spectral analysis and Extrema moni toring Mass storage and remote control A sophisticated mass storage and remote control package is available to assist users involved in automated and computer aided testing Convenient portability for field applica tions is also provided by a lap top computer e SINGLE SHOT BANDWIDTH NYQUIST FREQUENCY Vs TIME BASE SETTING E LU Z 7 x O GU E 50 e a Wy 2I 9z N K aid 10 5 IN 1 if N 0 5 ay X N Ne Ne are S i 10n
56. is abandoned On Warning processing is performed but the results are corrupted ERROR FFT src wfm is in sequence mode FFT of sequence mode waveform has not been implemented Processing abandoned ERROR FFT sre wfm is in frequency domain FFT of a frequency domain waveform has not been implemented Processing abandoned ERROR FFT AVG src wfm not in freq domain FFT Power Average mode Function F only is active only if Function E is defined as FFT Processing abandoned You should define Function E as FFT Fast Fourier Waveform Processing Option WPO02 V 2 06FT 11 21 11 8 WARNING FFT src wfm ils mode extended In the Interleaved Sampling Mode there are two time base settings 1 usec div and 0 5 usec div in which the record of 25000 points shown on the screen is incomplete Starting at the left hand edge of the screen 0 08 and 0 4 div respectively are blank Before computing the FFT the leftmost valid point of such records is copied leftward through to the left edge of the screen This will generate harmonic components not present in the original record If possible you should use the Single shot mode before FFT at these time base settings WARNING FFT src wfm roll mode incomplete In the Roll Mode time div lt 0 5 sec you can stop the acquisition of a trace before it fills the entire width of the screen The remaining portion of the record is blank on the display but the memory contents remain un
57. now 5 gigasamples sec and the risetime of the pulse is very clearly defined Note The procedure to follow for Expand B is identical to the above except that in Step 2 the EXPAND B push button 46 is pressed rather than the EXPAND A push button Basic 9400A Waveform Measurements and Operating Procedures 8 5 8 4 Reoall Special Modes Plotter Chi gt i V Meru OFF T div60ne Ch 2 EU ny Trig 00div CHAN 1 Figure 8 4 Sequential Recording of Single Events in Segmented Memory I 31 Segment Memory Partitioning Using the same 100 nsec signal and front panel settings described in Section 8 2 and with your pulse generator in external or manual trigger perform the following procedure 1 Call the Panel Status menu by pressing push button 2 2 Press Modify Segments push button 4 as often as necessary to display the value 31 in the Segments for SEQNCE line 3 Set RANDOM INTERLEAVED SAMPLING to OFF 4 Set the Time Base to 1 wsec division 5 Select SEQNCE trigger mode 29 6 Press the Return push button 10 to return to the main menu 7 Set DUAL GRID 14 to ON 8 Actuate your generator external trigger a total of 31 times in order to generate 31 signals to be recorded At this point a compacted trace of 31 segments is displayed in the upper grid Trace expansions EXPAND A and EXPAND B must be used to display details of one or two selected segments 9 Press EXPAND A 46 in order to expand CHAN 1
58. or to inspect the current setup the trace FUNCTION E or F 48 must be turned ON Select this trace for display control with the SELECT 44 push button and press REDEFINE 45 A full page setup menu for this function appears on the screen Return to the normal waveform display by either pressing the Return soft key 10 or the REDEFINE 45 push button The currently selected processing function and its parameters may be modified with the soft keys First select the field to be modified The rectangular frame around parameter values indicates the currently selected field Pressing the Previous FIELD push button 2 will cause the frame to move towards the top of the list whereas pressing the Next FIELD push button 3 will cause the frame to move downwards Following field selection the current value of the field may be modified by pressing either the Previous or Next VALUE push button 6 or 7 Since the identity of the lower fields may depend on the function chosen modify the parameters from top to bottom The following waveform processing functions are available Average summed and continuous averaging Extrema Roof for maxima Floor for minima Arithmetic Sum Difference Product and Ratio Functions Negation Integral Differentiation Square and Square Root Smoothing 1 3 5 7 and 9 point smoothing WPO1 Waveform Processing Option 10 2 10 2 1 Summed Average Summed averaging consists of the re
59. plotter see the TRANSMIT command or used as Prompt see COMM PROMPT command The string must be delimited by string delimiters The default string delimiter is lt gt and may be changed see the COMM STRDELIM command Example COMM STRDELIM 47 MSG OKAY Defines lt gt decimal ASCII 47 as the string delimiter and will display OKAY on the screen The TRANSMIT command also outputs characters that are specified in decimal ASCII using a nnn format Example TRANSMIT 27AB Can be used to transmit to the plotter the character ESC decimal ASCII 27 followed by lt A gt and lt B gt If the backslash character lt gt is to be transmitted along with other characters then lt gt is to be used o Example TRANSMIT A1 A2 Instructs the 9400A to transmit the string Al1 A2 to the plotter Note nnn or represent only one character of the ASCII string count Prompt The 9400A may generate a PROMPT see COMM PROMPT command when it decodes the lt END gt message in a command message This PROMPT will be put into a message as is done with all other 9400A responses see Section 7 6 7 7 Remote Operations 7 7 7 4 9 7 5 Errors and Adapted Values When it treats a command the 9400A checks its validity The list of errors is presented in Section 7 6 8 ERROR status byte In general A SYNTAX ERROR is produced when the structure of a command is wrong or if a command a key word param
60. same format but do not necessarily have the same number of characters However lt count gt is always treated as a WORD 16 bits whereas lt data gt may be chosen as a BYTE 8 bits or as a WORD The choice of formats see COMM FORMAT command is the following BYTE 8 bits value WORD 16 bits value HEX xx 2 hex digits XXXX 4 hex digits UNSIGNED FIXED nnn 3 decimal digits nnnnn 5 decimal digits UNSIGNED SHORT n 1 to 3 decimal digits nnnnn 1 to 5 decimal digits Remote Operations 7 9 The HEX and UNSIGNED FIXED are fixed size formats whereas UNSIGNED SHORT is a variable size format Therefore it requires commas to separate the values Examples HEX format L000A0102030405060708090A UNSIGNED FIXED L 10 1 2 3 4 5 6 7 8 9 10 Each dot repre sents a space character UNSIGNED SHORT L 10 1 2 3 4 5 6 7 8 9 10 Note The conversion type and the size must be fixed before reading AND writing data Data transfers via RS 232 C can only be made in ASCII formats If the host computer allows only small amounts of data to be sent or read the transfer may be partitioned into several blocks of the selected format The maximum length of each block is determined by the COMM BLOCKSIZE command The length includes all bytes or characters of the block as well as characters which may compose the lt TRAILER gt and lt END gt The transfer will be structured as follows k Block lt TRAILER gt lt END gt
61. the artificially completed sweeps as GND lines Display Commands 1 2 DUAL GRID DG lt gt lt ON gt lt OFF gt Examples DUAL GRID ON Instructs the 9400A to display dual grids DG OFF Instructs the 9400A to display a single grid of 8 x 10 squares TRACE CHANNEL 1 TRC1 ra ae gt TRACE CHANNEL 2 TRC2 lt ON gt TRACE EXPAND A TREA lt OFF gt k TRACE EXPAND B TREB TRACE MEMORY C TRMC TRACE MEMORY D TRMD TRACE FUNCTION E TRFE TRACE FUNCTION F TRFF The 9400A sets the ENVIRONMENT ERROR ify 4 traces are already ON and a command is received to turn a 5 trace ON Remote Operations 3 4 Examples TRC1 Instructs the 9400A to send a message indicating whether the display of channel 1 is on or off TRMC OFF Instructs the 9400A to turn the display of memory C off SELECT SEL X T lt gt lt EXPAND A EA gt lt EXPAND B EB gt lt MEMORY C MC gt lt MEMORY D MD gt lt FUNCTION E FE gt lt FUNCTION F FF gt e e X T T Selects a display trace similar to the front panel control Thereafter the commands VERT GAIN VERT POSITION TIME MAGNIFIER HOR POSITION and REDEFINE will be applied to the SELECTed trace The 9400A sets the ENVIRONMENT ERROR if the SELECTed trace is OFF VERT GAIN VG lt gt lt 1 000 to 2 500 gt VERT GAIN is applied to the SELECTed trace This command instructs the 9400A to modify t
62. this moment it will read the binary value 11110000 coded as the decimal value 240 128 64 32 16 The Main Status Byte STB 1 acts as an accumulator of all condition bits Thus several bits are set After reading STB 1 all bits will be cleared and no more Service Requests are generated until some new event occurs Remote Operations 7 56 SECTION 8 BASIC 9400A WAVEFORM MEASUREMENTS AND OPERATING PROCEDURES The purpose of this section is to provide the user with a concise overview of the wide range of measurement capabilities offered by the LeCroy 9400A While you may already be familiar with traditional oscilloscope operation this brief outline will help to acquaint you with the many powerful features of the 9400A kkkkkkkk NOTE KkKKKKKKK In the following section we have chosen to set all acquisition parameters from the Panel Status menu however it is not necessary to be in this menu to make front panel setting changes In the majority of cases viewing the Abridged Panel Status Field IV will provide all necessary indications Repetitive Signal Acquisition I Applying Probe Calibration Signal 1 Connect the P9010 probe connector to CHAN 1 input 21 2 Connect the probe s grounding clip to lug 20 and touch the tip to lug 19 3 In the Main Menu press the Recall PANEL push button 5 4 Recall the Default panel setup 9 5 Return to the Main Menu by pressing the Return push button 10 6
63. throughout the world r i Copyright January 1989 LeCroy is the registered trademark of LeCroy Corporation All rights reserved Information in this publication supersedes all earlier versions Specifications subject to change without notice TDS 013 062 a ie FAST FOURIER PROCESSING PACKAGE 25 000 POINT TRANSFORMS SPECTRAL AVERAGING LeCro WP02 SPECTRUM ANALYSIS FIRMWARE FOR MODEL 9400A DIGITAL OSCILLOSCOPE 9400AWPO02 50 to 25 000 point FFTs over Two Channels Simultaneously Frequency Resolution from 1 Milli Hz to 50 MHz Up to 5 GS sec Sampling Rate Time and Frequency Domain Averaging Wide selection of FFT Display Formats and Window Functions modulated signal top trace is analyzed in the frequency domain using the 9400A s FFT cessing capability which provides power middle and magnitude lower information side lobes 6 kHz from the fundamental frequency are clearly visible The WPO2 Spectrum Analysis Firmware Package brings powerful FFT w FREQUENCY DOMAIN routines to extend the capabilities of the 9400A Digital Oscilloscope into frequency domain measurement and analysis It is available as an option MEASUREMENTS or may be retrofitted AND ANALYSIS The LeCroy 9400A provides 175 MHz bandwidth 100 megasamples sec 8 bit ADCs 2 DC accuracy 1 optional 32K memory per channel and up to 192K of waveform storage memory It is fully programmable over RS 232 C or optional
64. trace for an extrema accumulation or REDEFINE RDF ARITHMETIC ARI lt a type gt lt maxpts gt lt sourcel gt lt source2 gt lt m fact gt lt a const gt configures the SELECTed trace for waveform arithmetic on two sources or WPO1 Waveform Processing Option 10 9 REDEFINE RDF FUNCTIONS FNC lt f type gt lt maxpts gt k lt sourcel gt lt m fact gt lt a const gt configures the SELECTed trace for a mathematical waveform function on a Single source or REDEFINE RDF SMOOTHING SMO lt s type gt lt maxpts gt lt sourcel gt configures the SELECTed trace for a smoothing operation The parameters have the following options Maximum number of data points to be used in the computation 50 125 250 625 1250 2500 6250 12500 25000 32000 lt maxpts gt Default 1250 RAR AA AA AN N N N N NP N NP N N N VV N Any other number generates a semantic error lt source gt lt CHANNEL 1 C1 gt Source waveform lt CHANNEL 2 C2 gt lt FUNCTION E FE gt Default CHANNEL 1 lt sourcel gt lt CHANNEL 1 C1 gt Source waveform s lt source2 gt lt CHANNEL 2 C2 gt lt MEMORY C MC gt Default CHANNEL 1 lt MEMORY D MD gt lt FUNCTION E FE gt NOTE a distinction is made between lt source gt and lt sourcel gt to indicate the fact that averaging and extrema cannot be executed on MEMORY C or MEMORY D whereas a
65. value greater than 1 0 is given 7 6 4 Plotter Commands 1 PLOTTER PT lt gt or PLOTTER PT lt name gt lt port gt lt speed gt lt pens gt Remote Operations 7 20 lt name gt lt port gt lt speed gt lt pens gt Configures Examples GRAPHTEC GR HEWLETT PACKARD HP PHILIPS PH TEKTRONIX TEK il NANA NP NP NP Nw RS232 RS gt GPIB GP gt AN il AN NORMAL SPEED NS gt lt LOW_SPEED LS gt 1 to 9 the 9400A for a predefined plotter PLOTTER HP RS NS 2 Configures the 9400A for a Hewlett Packard plotter connected to the RS 232 C plotter port running at normal speed with 2 pens This is how the 9400A must be configured for the HP7470 and HP7475 or compatible plotters l PT GR GP LS 4 2 PLOT SIZE Confi A5 A4 A3 or PLOT SIZE Configures the 9400A for a Graphtec FP5301 or compatible plotter connected through GPIB running at low speed for plotting on transparencies with 4 pens PS a oo 2 lt A5 gt d lt A4 gt lt A3 gt gures the 9400A to plot onto a predefined paper size 148 mm by 210 mm compatible with U S 5 1 2 by 8 1 2 210 mm by 297 mm compatible with U S 8 1 2 by 11 297 mm by 420 mm compatible with U S 11 by 17 PS NON STANDARD NSTD lt grid gt lt x gt lt y gt Configures the 9400A to plot onto a non standard paper size lt grid gt 00 0 MM to 99 9 MM Rem
66. zoom horizontal expansion operates simul taneously on live stored and processed waveforms expanding up to 100 times Vertical expansion from 0 4 up to 2 times for non processed waveforms up to 10 times for processed waveforms Screen dump Single or multi pen digital plotters are menu selected The 9400A supports the HP 7400 series as well as the Tektronix 4662 Philips PM 8151 Graphtek WX 4638 6 and compatible models Screen dumps are activated by a front panel push button Cursors Two time cursors give time resolution of 0 2 of full scale for unexpanded traces up to 0 002 for expan ded traces The corresponding frequency information is also provided Two voltage cursors measure voltage differences to 0 2 of full scale for each trace A cross hair marker measures absolute voltage versus signal ground as well as the time relative to the trigger eo RS et mh ae ae l g BS i t E E Z For instant hard copies the 9400A s screen dump feature sends data directly to the DP9001 8 pen digital plotter ORDERING INFORMATION Oscilloscope and Options A wide range of oscilloscope accessories including cameras and a scope cart pictured are available for the 9400A Oscilloscope Accessories cont d Code Description CA9001 Camera using Polaroid film and Hood S 9400A G Digital Oscilloscope CA9002 Camera Adapter 35mm with Hood 9400AOP01 High precision Option CS9400 Certified Calibration 9400A0P03 Print
67. 0 each sweep is transmitted as a separate block The parameter lt values gt applies to the number of data values per sweep in the case of SEQNCE data Note If the 9400A receives a command to read CHANNEL 1 or CHANNEL 2 while it is acquiring data the execution of the command will be delayed until the TRIGGER has arrived The 9400A sets the VALUE ADAPTED bit if lt intval gt is greater than 16000 it is adapted to 16000 if lt values gt corresponds to too large a value it is adapted to the number corresponding to the last accessible value if lt addr gt is out of range it is adapted to the nearest legal address if lt sweep gt is higher that the selected number of sweeps it is adapted to the last sweep number Remote Operations 7 25 Examples READ C1 DE READ MC DA READ MC DA 000 READ C1 DA 5 100 1000 READ MD DA 2 READ CHANNEL 2 Instructs the 9400A to transmit the waveform descriptor of Channel 1 in the format described in Section 7 7 If the 9400A is armed and waiting for a trigger the execution is deferred until the waveform is acquired Instructs the 9400A to transmit all data values of Memory C which would appear on the screen but no descriptor or trigger time s Instructs the 9400A to transmit all data points of Memory C starting 000 invisible points before the left hand side of the screen up to the last value at the right hand side Instruc
68. 000 250 000 250 000 250 000 250 000 625 000 625 000 625 000 625 000 625 000 625 000 625 000 625 000 1 250 1 250 1 250 1 250 1 250 1 250 1 250 1 250 1 250 kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz MHz MHz MHz MHz MHz MHz MHz MHz MHz Number of Points 125 250 625 1250 2500 6250 12500 25000 50 125 250 500 1250 2500 5000 12500 25000 50 100 250 500 1000 2500 5000 25000 125 250 625 1250 2500 6250 12500 25000 50 125 250 1250 2500 5000 12500 25000 11 26 SS RIS Time div 0 1 msec 0 2 msec 0 5 msec 1 msec 2 msec 5 msec 10 msec 20 msec 20 usec 50 usec 0 1 msec 0 2 msec 0 5 msec 1 msec 2 msec 5 msec 10 msec 10 usec 20 usec 50 usec 0 1 msec 0 2 msec 0 5 msec 1 msec 5 msec 10 usec 20 psec 50 psec 0 1 msec 0 2 msec 0 5 msec 1 msec 2 msec 2 usec 5 usec 10 usec 20 usec 50 usec 0 1 msec 0 2 msec 0 5 msec 1 msec Fast Fourier Waveform Processing Option WP02 V 2 06FT FNyquist Number of SS RIS Time div Points 2 500 MHz 50 SS RIS 1 usec 2 500 MHz 100 SS RIS 2 usec 2 500 MHz 250 ss 5 usec 2 500 MHz 500 SS 10 usec 2 500 MHz 1000 ss 20 usec 2 500 MHz 2500 SS 50 psec 2 500 MHz 5000 SS 0 1 msec 2 500 MHz 25000 ss 0 5 msec 6 250 MHz 125 SS RIS 1 usec 6 250 MHz 250 SS RIS 2 usec 6 250 MHz 625 SS 5 use
69. 00A provides measurement capa bilities superior to those of common swept spectrum analyzers In particular it is now possible to perform spectral analysis on continuous and single events at an eco nomic price And it enables users to obtain time and frequency values simultaneously and to compare phases of the various frequency components with each other Rather than the commonly used power of two record lengths the routines used in the WP02 package feature decimal record lengths which can be selected in a 1 2 5 order Resulting spectra are there fore also calibrated in convenient decimal Hertz values SPECIFICATIONS VERTICAL ANALOG SECTION Inputs two BNC connectors Sensitivity 5 mV div to 1 V div at 50 2 impedance and 5 mV div to 5 V div at 1 MQ impedance detents at 1 2 5 variable 1 2 5 DC accuracy standard lt 2 optional S lt 1 Bandwidth 3 dB 50 2 DC 175 MHz at 10 mV div up to 225 MHz at 1 V div DC 150 MHz at 5 mV div 1 MQ AC 10 Hz 100 MHz typical 1 MQ DC DC 100 MHz typical Bandwidth limiter 30 MHz 3 dB Input impedance 1 M2 50 pF and 50 9 characteristic Maximum input 250 V DC peak AC at 1 MQ 5 V DC 500 mW or 10 V peak AC at 50 9 Offset 8 divisions in 0 04 division increments a a L a o The FFT s digital nature ensures high accuracy stabil ity and repeatability These are strongly supported by the 9400A s superb DC and dynamic accuracy speci fications
70. 0A is in the Random Interleaved Sampling RIS mode a sufficient number of triggers must be obtained to complete waveform reconstruction after which the waveform will be displayed No further signals can be acquired until the SINGLE HOLD button has been pressed again When the 9400A is in the Roll mode gt 500 msec div pressing the SINGLE HOLD button causes data acquisition to immediately halt and the display to freeze NORM Selected using button 29 When in the normal NORM trigger mode the 9400A continuously digitizes the input signal Whenever a valid trigger is received the acquired waveform is displayed on the CRT digitization starts again and the trigger circuit is re armed If no subsequent trigger is received within 2 seconds previously acquired waveforms are erased from the screen The absence of a valid trigger will thus result in a blank screen To retain the last acquired waveform indefinitely in the NORM mode the 9400A s Auto store feature is used Auto store can be called via the Special Modes menu described in Section 5 2 5 When the 9400A is in the RIS mode a sufficient number typically 200 of valid triggers is required for each display of a complete waveform In the Roll mode gt 500 msec div the 9400A samples the input signals continuously Each point is immediately updated on the display This results in a trace which moves from right to left across the CRT In the NORM mode triggers are ign
71. 1 SECTION 3 INSTALLATION Safety Information The 9400A has been designed to operate from a single phase power source with one of the current carrying conductors neutral conductor at ground earth potential Operation from power sources in which both current carrying conductors are live with respect to ground such as phase to phase on a tri phase system is not recommended as the 9400A is equipped with over current protection for one mains conductor only The 9400A is provided with a three wire electrical cord containing a three terminal polarized plug for mains voltage and safety ground connection The plug s ground terminal is connected directly to the frame of the unit For adequate protection against electrical hazard this plug must be inserted into a mating outlet containing a safety ground contact Operating Voltage Prior to powering up the unit make certain that the mains voltage for your area corresponds to the mains voltage value appearing in the window of the selector box at the rear of the 9400A The operating voltage for the 9400A is either 115 V or 220 V at 48 to 62 Hz Switching from one mains voltage to another is not possible If the mains voltage appearing in the window differs from that used in your area contact the nearest LeCroy sales office or distributor kkkkkkkkkkk CAUTION KKKKKEKKKKKK If a 9400A set for 115 V is plugged into a 220 V power source severe damage can occur Before powering up the uni
72. 11 Telex 41 90 58 Innovators in Instrumentation Fax 914 425 8967 Fax 022 782 39 15 Other sales and service representatives throughout the world Copyright March 1990 LeCroy is the registered trademark of LeCroy Corporation All rights reserved Information in this publication supersedes all earlier versions Specifications subject to change without notice TOS 013 003 FUNCTIONAL DESCRIPTION FOURIER PROCESSING Fourier processing is a mathematical technique which permits a time domain waveform to be described in terms of frequency domain magnitude and phase or real and imaginary spectra in spec tral analysis a waveform can be sampled and digi tized then transformed by a discrete Fourier trans form DFT Fast Fourier Transforms are a set of algorithms used to reduce the computation time by better than a factor of 100 for a 1000 point FFT needed to evaluate a DFT The principal advantage of the FFT is the rapidity with which it can analyze large quantities of waveform samples In effect using standard measurement techniques it converts a time domain instrument into digital spectrum analyzer The WPO2 Fast Fourier Processing Package enhances the outstanding features of the LeCroy 9400A Digital Oscilloscope it provides high resolution wide band spectrum analysis capabilities along with sophisticat ed window functions and fast processing FFT AND THE LeCROY 9400A DIGITAL OSCILLOSCOPE In FFT mode the 94
73. 16 Frequency bins The FFT algorithm takes a discrete source waveform defined over N points and computes N complex Fourier coefficients which are interpreted as harmonic components of the input signal For a real source waveform imaginary part equals 0 there are only N 2 independent harmonic components The FFT corresponds to analyzing the input signal with a bank of N 2 filters all having the same shape and width and centered at N 2 discrete frequencies Each filter collects the signal energy falling into the immediate neighborhood of its center frequency and thus it can be said that there are N 2 frequency bins The distance in Hz between the center frequencies of the bins is always Af 1 T where T is the duration of the time domain record in seconds The width of a bin is equal to f The width of the main lobe of the filter centered at each bin depends on the window function used With the Rectangular window the width at 3 92 dB is 1 0 bins Other windows have wider main lobes consult Table 11 3 Frequency Range The range of frequencies computed and displayed in the 9400A is from 0 Hz at the left hand edge of the screen to the Nyquist frequency at 5 or 6 25 divisions Frequency Resolution In a narrow sense the frequency resolution is equal to the bin width f That is if the input signal changes its frequency by Af the corresponding spectrum peak will be displaced by Af For smaller changes of fre
74. 2000 pts 320 ps It is important to realize that at the fastest sampling rate of 10 nsec per point a record always covers a time interval of 320 usec regardless of the time base which can range from 50 nsec div to 20 wsec div However the trigger point is always interpreted relative to the left hand edge of the screen i e relative to the address point O of the record Example Compare a time base of 20 usec div to a time base of 1 usec div both with a pre trigger of 10 percent i e 1 division to the right of the left edge of the screen 20 ps div 140 ps 20 US 12000 left edge fo trigger point of screen displayed record 20000 pts 200 us digitized record 32000 pts 320 US 1 ps div trigger 1000 point 31000 0 left edge of screen digitized record 32000 pts 320 ys displayed record 1000 pts 10 ws Remote Operations 7 49 7 10 7 10 1 In RIS the 9400A digitizes 24000 data points except 24800 at 1 usec div and 25000 at 2 wsec div see Section 5 1 2 In this mode and in SEQNCE mode it may happen that the memory is slightly too small to cover the entire screen In this case the waveform does not extend all the way to the left hand side of the display screen and the address of the first valid data point of the record is a positive number The principle is still maintained that address 0 corresponds to the data point at the left edge of the screen even if it refers to a virtual dat
75. 400A s interactive menus may be selected by pressing buttons 2 10 Figure 5 8 shows the available menus as they appear on the 9400A To obtain a given menu press the button adjacent to the menu desired ri e ttt STATUS Ch 4 oye Menu OFF T div 2 ns Ch2 2 V Trig 20div 9400A Main Menu and RELATED MENU KEYS Figure 5 8 Store Menu Using the STORE button 1 it is possible to store either or both of the waveforms currently in the 9400A s acquisition memories into reference Memories C and or D To store the currently acquired waveform first stop the acquisition by pressing the SINGLE HOLD button 29 Once acquisition has Stopped press button 1 and respond to the messages displayed to the left of the screen The options are shown in Figure 5 9 Manual Operation EE T div 2 me m ee Trig LINE STORE TRACE MENU Figure 5 9 Pressing buttons 2 3 6 or 7 causes an identical copy of the displayed waveform or waveforms to be stored into reference Memories C and or D If acquisition is taking place when the store button 1 is pressed the user is prompted with the message STOP ACQUISITION IN ORDER TO STORE Manual Operation 5 19 Panel Status Menu The Panel Status menu provides a complete report of front panel control settings and permits on screen adjustment of acquisition parameters ACQUISITION PARAMETERS VERTICAL Chan 1 Fixed V div 60 mV Total V div 50 0 a
76. 5 340 345 350 355 360 365 370 375 380 385 390 425 IF EOF 1 THEN 335 TIMER STOP AS INPUTS LOC 1 1 CS MID S AS 1 LEN AS L INSTR CS CPRMS IF L gt O THEN L L 1 CS MIDS A 1 L CYCLE FALSE IF ECHO THEN PRINT 2 CS IF STORE THEN FOR I 1 TO LEN CS PRINT 3 MIDS CS I 1 NEXT I WEND TIMER OFF RETURN r SUBROUTINE OPEN DISK FILE t CLOSE 3 LINE INPUT Specify dir and disk file name A OPEN AS FOR OUTPUT AS 3 STORE TRUE LINE INPUT Enter READ command A gt abort CS IF CS A THEN 450 IF INSTR CS R lt gt 1 THEN PRINT 2 Wrong syntax GOTO 450 ELSE PRINT 3 CS PRINT 1 CS L INSTR CS IF L 0 THEN PRINT 3 ELSE PRINT 3 MIDS C L LINE INPUT Echo data to screen Y N AS IF AS N THEN ECHO FALSE PRINT 2 Uploading ELSE ECHO TRUE GOSUB 300 STORE FALSE ECHO TRUE CLOSE 3 RETURN t SUBROUTINE READ DISK FILE CLOSE 3 LINE INPUT Specify dir and disk file name AS OPEN A FOR INPUT AS 3 A CHR 27 R PRINT 1 A LINE INPUT Specify target memory C D BS IF BS lt gt D THEN BS C LINE INPUT 3 C PRINT 2 Read command was C LINE INPUT 3 CS AS WT M BS CS CHRS 13 PRINT 1 AS LINE INPUT Echo data to screen Y N AS IF AS N THEN ECHO FALSE PRINT 2 Downloading ELSE ECHO TRUE WHILE NOT EOF 3 AS INPUTS 1 3 IF ECHO THEN PRINT 2 AS PRINT 1 AS WEND CLOSE 3 GOSUB 300 AS CHRS 27 L PRINT 1 AS GOSUB
77. 50 to 32000 in 10 steps Number of points per block varies with the time base and the number of blocks selected Typical execution time for 1250 points 700 msec N POINT SMOOTHING Filter coefficients with weighting factors for successive data points 3 point 1 2 1 1 4 5 point 1 4 6 4 1 16 7 point 1 6 15 20 15 6 1 1464 9 point 1 8 28 56 70 56 28 8 1 1 256 Number of points processed 50 to 32000 in 10 steps Vertical expansion 2 times maximum Typical execution time of 1250 points 500 msec EXTREMA MODE Logs all extreme values of a waveform over a pro grammable number of sweeps Maxima and minima are displayed separately by ROOF and FLOOR traces Number of sweeps selected in a 1 2 5 sequence from 1 up to 1 000 000 Number of points processed 50 to 32000 in 10 steps Glitches as short as 10 nsec or 0 04 of the time base setting are displayed Vertical expansion 2 times maximum Typical execution time for 1250 points 300 msec CHAINING OF OPERATIONS Two functions can be automatically chained using functions E and F E CH1 CH2 F summed average of E Example Manual chaining using memory C and D for intermediate results may continue indefinitely REMOTE CONTROL All front panel controls and Waveform Processing functions are fully programmable via either the 9400A s GPIB or RS 232 C interfaces Simple English like mnemonics are used STORED FRONT PANELS Up to 7 front panel
78. 50n wOn 500n tp 5u 110p 50u 100p are 500 tm G TIME BASE SETTING secidiv Single shot bandwidth is a function of sampling rate Long memories enable higher sampling rates at equal time base settings Above the 9400A solid line is compared to oscilloscopes with 1K dotted line and 512 points dashed line of memory At slower ltime base settings the single shot bandwidth of the 9400A expressed as Nyquist frequency is typically 25 times higher than in oscilloscopes with 1K memory and 50 times higher than in those with only 512 points x mnn SPECIFICATIONS VERTICAL ANALOG SECTION Bandwidth 3 dB 50 Q DC 175 MHz at 10 mV div up to 225 MHz at 1V div DC 150 MHz at 5 mV div 1 MQ AC lt 10 Hz 100 MHz typical 1 MQ DC DC 100 MHz typical Single shot DC 50 MHz Nyquist Input impedance 1 MQ 50 pF and 50 Q 1 Channels Two standard BNC connector inputs Sensitivity range 5 mV div to 1 V div at 50 Q impedance and 5 mV div to 5 V div at 1 MQ impedance detents at 4 2 5 1 2 5 continuously variable Offset 8 divisions in 0 04 division increments DC accuracy Standard lt 2 optional lt 1 Noise lt 0 45 RMS Bandwidth limiter 3 dB 30 MHz Max input voltage 250 V DC peak AC at 1 MQ 5 V DC 500 mW or 10V peak AC at 50 Q VERTICAL DIGITAL SECTION ADCs One per channel 8 bit flash Conversion rate Up to 100 megasamples sec for transient sig
79. 62 125 or 250 blocks Trigger Sources CHANT CHAN2 LINE EXT EXT 10 Slope Positive negative window Coupling AC LF REJ HF REJ DC Modes Sequence stores multiple events in segmented acquisi tion memories Auto automatically re arms after each sweep If no trig ger occurs one is generated at 2 Hz repetition rate Normal re arms after each sweep If no trigger occurs after 2 sec the display is erased Single hold holds display after a trigger occurs Re arms only when the single button is pressed again Pre trigger Adjustable in 0 2 increments to 100 Post trigger delay Adjustable in 0 02 division increments up to 10 000 divisions External trigger input 1MQ lt 30pF 250V max 2V in EXT 20V in EXT 10 Rate gt 200 MHz SELF TESTS Auto calibration Performed every 20 minutes or whenever the gain or time base parameters are changed provides accuracies of DC gain 2 1 optional of full scale Offset 0 5 of full scale 5022 only Time 20 psec RMS During the warming up period auto calibration is carried out at 1 minute intervals unless the oscilloscope is in single or sequence trigger mode DISPLAY CRT 12 5 x17 5 cm 5 x 7 inches magnetic deflection vec tor graphics system Resolution 1024 x 1024 addressable points Grid Internally generated separate intensity control for grid and waveforms Single and dual grid mode Expansion Dual
80. 625 000 MHz 625 RIS 50 nsec 625 000 MHz 1250 RIS 0 1 usec 625 000 MHz 2500 RIS 0 2 usec 625 000 MHz 6250 RIS 0 5 psec 625 000 MHz 12500 RIS 1 usec 625 000 MHz 25000 RIS 2 usec 1250 000 MHz 50 RIS 2 nsec 1250 000 MHz 125 RIS 5 nsec 1250 000 MHz 250 RIS 10 nsec 1250 000 MHz 500 RIS 20 nsec 1250 000 MHz 1250 RIS 50 nsec 1250 000 MHz 2500 RIS 0 1 usec 1250 000 MHz 5000 RIS 0 2 usec 1250 000 MHz 12500 RIS 0 5 usec 1250 000 MHz 25000 RIS 1 usec 2500 000 MHz 100 RIS 2 nsec 2500 000 MHz 250 RIS 5 nsec 2500 000 MHz 500 RIS 10 nsec 2500 000 MHz 1000 RIS 20 nsec 2500 000 MHz 2500 RIS 50 nsec 2500 000 MHz 5000 RIS 0 1 usec 2500 000 MHz 25000 RIS 0 5 usec Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 28 C H T T T T T T T T T T T T T T T T T T T T em 11 9 References Bergland G D A Guided Tour of the Fast Fourier Transform IEEE Spectrum July 1969 pp 41 52 A general introduction to FFT theory and applications Harris F J On the Use of Windows for Harmonic Analysis with the Discrete Fourier Transform Proceedings of the IEEE vol 66 No 1 January 1978 pp 51 83 Classical paper on window functions and their figures of merit with many examples of windows Brigham E 0 The Fast Fourier Transform Prentice Hall Inc Englewood Cliffs N J 1974 Theory applications and implementation of FFT Includes discussion of FFT algorithms for N not a power of 2 Ramirez R W The FFT Fundamentals
81. A N M W M M M MMM MMM AMM Serial Number January 1990 THE LeCROY MODEL 9400A DIGITAL OSCILLOSCOPE North American Headquarters LeCROY Corporation 700 Chestnut Ridge Road Chestnut Ridge NY 10977 6499 U S A Tel 914 578 6097 European Headquarters LeCROY S A 2 rue Pr de la Fontaine Case postale 341 1217 Meyrin 1 Geneva Switzerland Tel 41 22 719 21 11 TABLE OF CONTENTS Section Page Number 1 GENERAL INFORMATION Technical Data Sheet 1 1 Warranty 1 1 Tez Assistance and Maintenance Agreements 1 1 1 3 Documentation Discrepancies 1 2 1 4 Service Procedure 1 2 Lid Return Procedure 1 2 1 6 Initial Inspection 1 3 2 PRODUCT DESCRIPTION 2 1 Introduction 2 1 2 2 9400A Architecture 2 1 23 ADCs and Memories 2 2 2 4 Trigger 2 3 205 Automatic Calibration 2 3 2 6 Display 2 3 d Manual and Programmed Control 2 3 3 INSTALLATION 3 1 Safety Information 3 1 3 2 Operating Voltage 3 1 3 3 Switching on the 9400A 3 2 4 DISPLAY LAYOUT 4 1 Menu Field 4 1 4 2 Time and Frequency Field 4 2 4 3 Trigger Delay Field 4 2 4 4 Abridged Front Panel Status Field 4 2 4 5 Displayed Trace Field 4 2 4 6 Message Field 4 3 5 MANUAL OPERATION S l Front panel Controls 5 1 Dedal Vertical 5 1 T es Time Base 5 4 Sek Trigger 5 6 5 1 4 Displaying Traces 5 12 Jeles Display Control 5 12 5 1 6 Screen Adjustments 5 1 Ss Lal Cursors 5 15 ii Ln Ln Ln Ln Ln Ln Ln NO bK KM A BO KA PO Ln Ln Ln amp Wh A Ln Ln C C C Ch
82. A features sampling rates of 100 megasamples sec for transient events Long memories and a versatile cursor system including voltage time and cross hair cursors give time measurements with an accuracy of 0 02 of the time base setting and reso lution of 0 002 full scale High resolution display The 9400A s large display screen produces bright stable razor sharp pictures of your signal under any repetition rate conditions Very accurate signal comparisons are possible as up to four waveforms live expanded or processed can be dis played simultaneously on the high resolution screen 1024 x 1024 pixels Long memories The long 32K acquisition memories of the 9400A Digital Oscilloscope capture waveforms with high fidelity At similar time base settings the 9400A s long memories allow sampling rates up to 25 times faster than that of instruments which have only 1K of acquisition memory see graph below Faster sampling rates ensure higher single shot bandwidth as well as significantly reducing problems caused by undersampling and aliasing The 9400A s long memo ries allow displayed waveforms to be expanded up to 100 times to show the finest signal details Transient recording With a sampling rate of 100 megasamples sec the 9400A is an extremely powerful transient recorder Long 32K data point acquisition memories combined with a continuously adjustable trigger from 100 pre trigger to 10 000
83. ATUS TO prt Pts div 200 ne 2600 200 ne 2600 Fun E F Trig Delay 9 8 Pre 9 8 Pre Tr Level Slope 00 div 00 div Tr Source Coupl CHAN 1 oc CHAN 1 Oc Memory Limite 7000 26000 7000 25000 Record Type SINGLE SINGLE Return PLOTTING MEMORY STATUS CHAN 1 and CHAN 2 Figure 5 11 Pressing button 2 3 or 4 while in the memory status menu will display the acquisition parameters of waveforms stored in acquisition expansion and storage memories respectively Manual Operation 5 22 Ch 1 2 STATUS Exp A B Men C D STATUS Fun EE PLOTTING Ch 414 2 STATUS Exp A B Mem C D STATUS Fun EE PLOTTING MEMORY STATUS Total V div OF Peet Coupling 8W Lisit Time Freq div TO ore Pte div Trig Delay Tr Lavel Slope Tr Source Coupl Memory Limite Record Type Proceseing Pointe Intval Sweeps LINE OO 0 25000 SINGLE Avgt1 s 1262 20 4 y 2 08FT Memory D 60 0 nV 0 my C 609 OFF 5 me 200 ne 2500 0 Pre 2O 0V ExT 10 DC 7000 26000 SINGLE TRACE A B EXPAND STATUS MENU Figure 5 12 MEMORY STATUS Total V div OF Faet Coupling Bw Limit Time Freq div TH prt Pte div Trig Delay Tr Level Slope Tr Source Coupl Memory Limite Record Type Processing Poirke Intval Sweeps MEMORY STATUS C and D Memory C 500 sY 4000 nV DC 60 0 OFF cme 80 ne 2500 4 Pro LINE oc 0 25000 SINGLE
84. Any action performed on the front panel is detected by the processor and the requested changes are implemented very rapidly During data acquisition measurement of input signals the internal processor is also busy with the data taking controls calculations and display generation Under certain conditions e g RIS mode or slow time base the response time of the front panel controls increases When for example the user tries to move a trace up or down on the screen it tends to move with a jumping motion Whenever slow response to the control knobs is noticed set the trigger mode to SINGLE Acquisition is stopped the display of the waveform is frozen and the response time of control knobs returns to normal Once waveform manipulations are done return to NORMAL or AUTO trigger Accurate Amplitude Measurements The 9400A digitizers are 8 bit analog to digital converters that measure the amplitude of input signals by subdividing them into 256 levels You can ensure maximum measurement accuracy by using the full dynamic range of the converters i e using input signals close to full scale Half scale signals are in 128 levels only reducing measurement accuracy by a factor of two To facilitate the adjustment of a full scale ADC signal the 9400A display has been designed to represent the zero level of the ADC as the bottom line of the grid Full scale level 256 is represented by the top line of the grid Getting the Most Out of Yo
85. BW is the equivalent noise bandwidth of the filter corresponding to the selected window Af is the current frequency resolution bin width The FFT Power Average Function F only takes the complex frequency domain data R _ I _ generated by Function E in step 6 above computes the square of the magnitude M 2 R 2 I 2 n n n and collects the result in a buffer 8 In the case of an FFT Power Average the final step is the computation of the selected Display Type format Magnitude Power Spectrum Power Density Computation speed of FFT In the 9400A the Fourier transform computation takes about 1 7 sec for a 1250 point FFT and just under one minute for a 25000 point FFT These times depend somewhat on the Window Type and the Display Type selected Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 15 11 6 You can speed up the computation by selecting a Transform Size smaller than 25000 The 9400A will select for you the effective Transform Size N equal to or smaller than your selected value depending on the actual number of points in the time domain record FFT 9400A Glossary Aliasing If the input signal to a sampling acquisition system contains components whose frequency is greater than the Nyquist frequency half the sampling frequency which results in less than two samples per signal period these components will be aliased That is their contribution to the sampled waveform will be indistingui
86. CK ERROR if an error in a block has been detected i e if The preamble is incorrect is not A L or I The preamble number indicating how many values the block has is greater than the number of values that are allowed SETUP DESCRIPTOR or TIME or greater than the number of values remaining until the end of the sweep buffer DATA The number of received values does not correspond to the number in the preamble In the case of ASCII blocks L format there are characters which are neither separator characters CR or LF nor digits In the case of ASCII blocks a value is greater than 255 BYTE or 8 bits transfer or greater than 65535 WORD or 16 bits transfer Other errors Too many or too few values have been received SETUP DESCRIPTOR or TIME Remote Operations 7 28 The string beginning with a character other than is received while the 9400A expects a block Such an error happens if the 9400A previously configured to work without the END block 1 receives less data than expected followed by a command Too many blocks have been received If the 9400A detects an error while receiving data blocks any remaining values in the block as well as the following blocks are purged until END block I or a command is received When a command is received instead of a block block transfer is aborted but the command will be decoded like any other command When a block is received without be
87. CTION F RD FF MEMORY C RD MC MEMORY D RD MD RECALL REC REDEFINE ARITHMETIC RDF AVERAGE RDF CHANNEL 1 RDF CHANNEL 2 RDF EXTREMA RDF FFT RDF FUNCTIONS RDF MEMORY C RDF MEMORY D RDF SMOOTHING RDF SCREEN DUMP SD C1 C2 FE FF MC MD ARI AVG C1 C2 EXTR FFT FNC MC MD SMO On in Ln J On On dl d Re s s OO e an ON a P L E LQ e WU to LA Kah d d Ka KA Ka d d KA KA O OFO P On C e e to W Uo J ON amp ked 10 D SEGMENTS SEG SELECT SEL SETUP SU STB STOP STORE STO TIME DIV TD TIME MAGNIFIER TM TRACE CHANNEL 1 TRC1 TRACE CHANNEL 2 TRC2 TRACE EXPAND A TREA TRACE EXPAND B TREB TRACE MEMORY C TRMC TRACE MEMORY D TRMD TRACE FUNCTION E TRFE TRACE FUNCTION F TRFF TRANSMIT TX TRIG COUPLING TRC TRIG DELAY TRD TRIG LEVEL TRL TRIG MODE TRM TRIG SLOPE TRP TRIG SOURCE TRS TSTB VERT GAIN VG VERT POSITION VP WAIT WRITE MEMORY C WT MC MEMORY D WT MD A 3 J ON to Ch gt SNS SI OS d d d Ch Ch Ch Ch C Ch Ca Cy Ch C HD O W Wo W lo W Lo L W 9 3 3 1 15 Additional RS 232 C only remote commands This subsection contains only those remote commands which are specific to RS 232 C communication lt ESC gt lt 7 6 10 7 lt ESC gt L 7 6 10 10 lt ESC gt 7 6 10 3 lt ESC gt 7 6 10 4 lt ESC gt C 7 6
88. Call the Panel Status menu 2 7 Set CHAN 1 Fixed VOLTS DIV to 10 mV 27 8 Adjust CHAN 1 VAR vernier 28 for a Total V div of 13 0 mV 9 Set CHAN 1 OFFSET to 50 mV 32 10 Set CHAN 1 COUPLING to DC 1 MQ 11 Adjust TRIGGER DELAY control 34 to 20 0 Pre 12 Adjust TRIGGER LEVEL control 33 to 00 division 13 Set TRIGGER COUPLING to AC 30 14 Set TRIGGER SOURCE to CHAN 1 23 15 Set TRIGGER SLOPE to POS 25 16 Set TRIGGER MODE to AUTO 29 17 Set TIME DIV control 36 to 5 msec 18 Note that at this TIME DIV setting INTERLEAVED SAMPLING RIS is OFF 19 Set BANDWIDTH LIMIT to OFF 50 Basic 9400A Waveform Measurements and Operating Procedures 20 Return to the Main Menu by pressing the Return push button 10 21 22 Set CHAN 1 to ON and CHAN 2 OFF 49 Set DUAL GRID mode to OFF 14 Resulting Display Chammel 1 6 me gt 10 nV tte t tlt bite te Ch 1 gt 10 my Menu OFF T div 6me Ch2 BUN The Trig 00div CHAN 1 Figure 8 1 P9010 probe has a x10 attenuation factor Thus the 1 V 976 Hz output calibration signal is displayed with a total amplitude of approximately 7 7 divisions at a Total V div setting of 130 mV In case of over or under shoot adjust the probe compensation trimmer located on the barrel of the P9010 for a clean square wave contour II 1 Acquisition of a 10 20 nsec Repetitive Signal Connect a fast pulse generator providing an output
89. Conventions 7 10 Interpretation of Waveform Data Values 7 10 1 Waveform Data in 8 bit Format 7 10 2 Waveform Data in 16 bit Format 7 11 Use of the Service Request SRQ Interrupts 7 11 1 Service Request in GPIB POS tn Wey Service Request in RS 232 C BASIC 9400A WAVEFORM MEASUREMENTS AND OPERATING PROCEDURES Repetitive Signal Acquisition Single Shot Acquisition Trace Expansion Expand A B Sequential Recording of Single Events in Segmented Memory 5 Slow Signal Recording 6 Window Triggering 7 8 CO CD GD amp Wh KA Storing and Recalling Front Panel Setups Signal Storage in Memories C D 9 Redefinition Function Expand Memories C D Auto Store in Memory C D 11 Common Expand Mode 12 Remote Control Via RS 232 C Port lt 13 Remote Control Via GPIB Option OPO2 Only 14 Making a Plot when the Computer the 9400A and the Plotter are All Connected Together on a GPIB Bus Option OPO2 Only 8 15 Configuring the Parallel Polling Option OPO2 Only GO GD GD GO GD GO GD GD GD CO p GETTING THE MOST OUT OF YOUR 9400A 10 9 1 Front Panel Controls 9 2 Accurate Amplitude Measurements 9 3 Accurate Time Measurements 9 4 Auto calibration WPO1 WAVEFORM PROCESSING OPTION 10 1 Processing Capabilities 10 2 Setting up a Waveform Processing Function Manually 10 2 1 Summed Average 10 2 2 Continuous Average 10 2 3 Extrema 10 2 4 Arithmetic 10 2 5 Functions 10 2 6 Smoothing iv 11 Remote Control of Wa
90. Data in 16 bit Format This format is only possible if the Waveform Processing option is installed The 9400A must be set to this format with the command COMM FORMAT In this format raw data i e 8 bit ADC output are represented in the most significant byte The least significant byte consists of 8 bits of zeros The unsigned 16 bit data values in the range 0 65535 are transformed into volts as follows V gain data 32768 8192 offset 200 25 200 vgain 80 The terms are identical to those of Section 7 10 1 except that the factors of the first expression are multiplied by 256 Use of the Service Request SRQ Interrupts A Service Request SRQ is generated whenever the RQS bit of the Main Status Byte STB 1 becomes 1 The user must demask the condition bits of interest in order to allow the generation of SRQ e g to make the 9400A generate an interrupt upon the occurrence of an overload in either channel 1 or 2 MASK 4 6 Sets the mask of the INTERNAL STATE byte STB 4 to the binary value 00000110 i e it demasks the 2 overload bits If an overload occurs the mask now allows the propagation of the bit to the INTERNAL STATE CHANGE bit of the Main Status Byte STB 1 MASK 1 8 Sets the mask of the Main Status Byte STB 1 to the binary value 00001000 i e it demasks the bit INTERNAL STATE CHANGE This now allows the propagation of this bit to the RQS bit of STB 1 Note that the RQS bit need not be demasked it
91. E CHANGE bit of STB 1 MASK 6 1 Sets the ERROR byte STB 6 to a non zero value allowing the propagation of errors to the ERROR bit of STB 1 Remote Operations 7 55 TIME DIV This legal command generates a response message which should be read by the host computer In addition the MESSAGE READY bit is set in STB 1 Because this bit is not demasked it does not generate a Service Request However if STB 1 were now read with STB 1 the binary value 10000000 80 in hexadecimal or 128 in decimal would be read and this bit would be cleared Overload 1 This event internal to the 9400A but due to too large a Signal at input 1 with 50 Q coupling sets the OVERLOAD1 bit of STB 4 Since this bit is demasked the INTERNAL STATE CHANGE bit of STB 1 is also set And because this bit is also demasked the RQS bit is set and the Service Request is generated If set to the default string it consists of sending 1 bell character decimal 7 followed by the carriage return character default value of lt END gt via RS 232 C to the host computer AAA This illegal command generates a syntax error and sets the ERROR byte STB 6 to the value 11 Since this byte is demasked the ERROR bit in STB 1 is also set And because this bit is also demasked it should also set the RQS bit and generate a Service Request However it cannot since it is already pending If the host computer reads the Main Status byte with the command STB 1 at
92. E when the display intensity controls have also been set to REMOTE Example TIME DIV TD lt gt lt 2 NS to 100 S gt TTME DIV is the long format of the command for controlling the time base TD is the short form equivalent of TIME DIV Either form may be used at all times The comma is the separator between the header and the first parameter It may be replaced by a space or by an equal sign lt gt or by any combination of these Note that subsequent parameters MUST be separated from each other by commas only The parentheses lt gt show that the choice of the first and only parameter is either lt gt or a time base value in the range of 2 nsec to 100 sec The asterisk lt gt indicates that this command can only be executed when the 9400A is in the REMOTE state However the query TIME DIV can be executed at any time Remote Operations 7 6 2 Acquisition Parameter Commands 1 TIME DIV TD lt gt lt 2 NS to 100 S gt Other available suffixes are US usec microseconds and MS msec milliseconds The 9400A sets the VALUE ADAPTED bit if an out of range value is given if a value outside the incremental steps of 1 2 5 is given Examples TD Instructs the 9400A to send the current time base value TD 20 US Sets the 9400A to 20 usec per division TIME DIV 12 MS Sets the 9400A to 10 msec since the value is modified from 12 msec to 10 msec
93. Example TIME DIV instructs the 9400A to transmit a character string representing its current time base value Answers from the 9400A are sent in a message followed by the TRAILER see COMM TRAILER command and lt END gt Remote Operations 7 5 7 4 5 7 4 6 Example When set to 100 nsec div the answer to the query would be TD 100E 09 lt CR gt lt LF gt lt END gt where lt CR gt lt LF gt is the default TRAILER and lt END gt another lt CR gt when using RS 232 C unless modified with the command RS CONF EOI line ACCOMPANYING lt LF gt when using GPIB If the 9400A generates multiple responses to a single message containing queries it will send a separate response for each query Flushing of the 9400A s Output Buffer When the 9400A generates an answer to a query or outputs a data stream in response to a transfer command the host computer should read the data If it fails to do so the 9400A may become blocked when trying to output data this does not occur with a response of less than 80 characters since the output is buffered Whenever the 9400A receives a new command message upon detection of the lt END gt of this message it flushes the output buffer of all responses due to the previous command message If the 9400A detects a new lt END gt from a new command message while still treating a previous command message it aborts those previous commands which generate output data but not the ne
94. FT REDEFINE RDF FFT lt disp_ Ype lt maxpts gt lt source lt window gt lt m_fact gt lt a_const gt lt z_suppr gt The parameters have the following options lt disp type gt lt POWER SPECTRUM PWS gt default lt POWER DENSITY PWD gt lt MAGNITUDE MAG gt lt PHASE PHASE gt lt REAL PART REAL gt lt IMAGINARY PART IMAG gt lt maxpts gt lt 50 gt lt 125 gt lt 250 gt lt 625 gt lt 1250 gt default lt 2500 gt lt 6250 gt lt 12500 gt lt 25000 gt Any other number generates a semantic error Fast Fourier Waveform Processing Option WP02 V 2 06FT lt source gt NOTE FUNCTION E can be a lt window gt lt m_fact gt lt a_const gt lt Z suppr gt lt CHANNEL 1 lt CHANNEL 2 lt MEMORY C lt MEMORY D lt FUNCTION E lt RECTANGULAR lt VON HANH lt HAMMING lt FLAT TOP C1 gt default C2 gt MC gt MD gt FE gt source only for FUNCTION F RECT HANN gt default gt HAMM gt gt gt FLT lt BLACKMAN HARRIS BH 0 01 to 9 99 9 99 to 9 99 lt OFF gt lt OND gt default 1 0 Multiplication factor applied to the source waveform before FFT computation default 0 0 Additive constant divisions applied to the source waveform before multiplication default If ON the DC component of the source waveform is forced to 0 T
95. Function DT1 Complete Device Trigger PP1 Parallel Polling remote configuration CU No Controller Functions E2 Tri state Drivers GPIB and RS 232 C Command Format Introduction All the remote control commands apply equally to communication via the GPIB and RS 232 C ports Note that GPIB commands should not be used when Option OP02 is not fitted in the 9400A Certain functions however which are part of the GPIB standard such as Device Clear or Group Execute Trigger must be implemented as separate commands for the RS 232 C interface see Section 7 6 10 The command syntax is compatible with IEEE Recommended Practice for Code and Format Conventions IEEE Standard 728 1982 In GPIB the predefined control commands such as Device Clear Group Execute Trigger Set Remote or Set Local are part of the device driver commands Therefore the 9400A only has English like commands for these functions in RS 232 C inferfacing applications The user must consult the manual for his GPIB interface driver in order to determine the form of these special commands Commands are formed of easy to read unambiguous English words with abbreviations typically 2 to 4 characters being used to achieve higher throughput Short and long formats may be freely substituted for one another The execution of certain commands depends on whether the 9400A is in the REMOTE or LOCAL state Remote Operations 7 3 7 4 2 7 4 3 When the 9400A is in LOCAL
96. Function E as the FFT of the signal channel and Function F as the FFT Power Average of Function E to obtain a stable spectrum of the input signal 8 You can display the FFT Power Average either on a linear scale Magnitude or on a dBm scale Power Spectrum or Power Density 11 5 2 Relationships of 9400A FFT output waveforms to the FFT computation steps For comparison of the 9400A s FFT results with those obtained from other FFT instruments the following information may be useful 1 In the 9400A s FFT computation the first step is the sub sampling of the source waveform Data points for the FFT calculation are measured at regular intervals over the full length of the waveform displayed on the screen You can select the maximum transform size in the FFT menu or via remote control The actual transform size N is selected to be equal to or smaller than the Displayed Record Length see Table 5 1 Exception you may get a 125 point transform when you have specified 50 points The sub sampling interval and the actual transform size selected provide the frequency scale factor in a 1 2 5 sequence Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 12 2 The second step is the addition of the selected constant to the sub sampled source waveform followed by multiplication by the selected factor 3 The third step is the multiplication of the source waveform by the selected window function 4 The fourth ste
97. GPIB interfaces Plotter drivers enable color archiving via a wide range of digital plotters FEATURES Long Record Transforms Extremely long record FFTs up to 25 000 points provide significant signal to noise ratio improvement on single phenomena Wide Band Frequency Domain Analysis Covers wide DC to 175 MHz bandwidth with high resolution in the frequency domain High Sampling Rates Up to 5 gigasamples sec effectively eliminates aliasing errors Broad Spectrum Coverage Executes FFTs over record lengths as long as 25 000 data points giving up to 12 500 spectral components at almost any sampling rate Dual Input Channels Both input channels can be analyzed simultaneously to allow comparison of independent signals for common frequency domain characteristics Fast Processing FFTs are processed and displayed rapidly e g a 1 250 point waveform is transformed in less than 1 75 sec a 50 point waveform within 300 msec Versatile Display Formats Frequency domain data may be presented as magnitude phase real imaginary log power log PSD power spectral density and all may be selected via menu options after signa capture Standard Window Functions Rectangular for transient signals von Hann Hanning and Hamming for continuous waveform data Flattop for accurate amplitude measurements Blackman Harris for maximum frequency resolution User definable Window Functions Specially defined window
98. Horizontal POSITION knob allows the user to scroll continuously through a displayed waveform However if the source trace was recorded in sequence mode i e a number of sequentially acquired traces was stored in partitioned memory blocks the movement of the Horizontal POSITION knob will be discrete allowing any single segment to be selected The Horizontal POSITION control affects only EXPAND A B Vertical POSITION knob 40 Vertically repositions the trace RESET button 41 Serves to reset previously adjusted VERT GAIN Vertical and or Horizontal POSITION to the following default values VERT GAIN Same as the original trace Vertical POSITION Same as the original trace Horizontal POSITION Center of the original trace In the Common Expand mode See Section 5 2 5 2 this button is used to synchronize the two intensified regions of EXPAND A and B VERT GAIN knob 42 Turning the knob clockwise allows vertical expansion by a factor of up to 2 5 Counterclockwise rotation allows vertical contraction by a factor of up to 2 5 If the vernier knob is not in the detent position it is possible to achieve vertical expansion by a factor of up to 5 Pressing RESET 41 returns gain control to a mid range plateau corresponding to a gain of 1 If the 9400A is equipped with WPOi the vertical gain is increased from 2 5 to 10 for averages mathematics and functions Manual Operation 5 13 5 1 6 TIME MAGNIFIER knob 43 This co
99. IONS E and F may operate on these reference memories and F may operate on E chaining of operations is possible Waveform processing can take an appreciable execution time when operating on many data points The user has the option of reducing the execution time by limiting the number of data points which are used in the computation WPO1 Waveform Processing Option 10 1 10 2 The 9400A then executes the waveform processing function on the entire waveform as displayed on the screen by taking every N point N depending on the time base The first point of such a reduced record is always the data value at address 0 i e the point on the left hand edge of the screen For readout and display the data record is re expanded to the original number of data points by linear interpolation By remote control the user can read either the entire expanded record or the reduced record In the second case the user must know the skip factor i e the value of lt intval gt in the read command see section 7 6 5 This factor can be inspected on the memory status display screen or by the inspect command Setting Up a Waveform Processing Function Manually It is generally good practice to stop data acquisition while preparing new conditions for waveform processing by setting the trigger mode to SINGLE because the response time might otherwise be slow depending on the current function setup In order to prepare FUNCTION E or F for new conditions
100. O gt lt PLOT PORT PPO gt Allows a HELP feature for the setup of remote control programs to be turned on When the HELP feature has been turned on the 9400A transmits character strings reflecting the message exchange between the host computer and the oscilloscope to the REMOTE or to the PLOTTER RS 232 C ports These HELP messages can be viewed ona normal display terminal COMM FORMAT CFMT A lt BYTE gt lt WORD gt or COMM FORMAT CFMT L lt BYTE gt lt HEX gt lt WORD gt lt UNSIGNED FIXED UFIX gt or COMM FORMAT CFMT L lt BYTE gt lt UNSIGNED SHORT USHO gt lt COMMA gt lt WORD gt n lt CR gt lt LF gt lt CRLF gt Selects a block transfer format as described in Section 7 5 In RS 232 C remote control only format L is available BYTE is for 8 bit data WORD is for 16 bit data This format is normally used for 16 bit data being read from Memory C Memory D Function E or Function F Raw data in Channel 1 and Channel 2 are always 8 bit data It is possible to read raw or processed data as 16 bit words Raw data have the measured 8 bit value in the most significant byte transmitted first and zero in the least significant byte transmitted after HEX results in 2 hexadecimal digits for each 8 bit value and in 4 hexadecimal digits for 16 bit value UNSIGNED FIXED uses 3 digits for BYTE data and 5 digits for WORD data UNSIGNED SHORT uses only as many digits as required but separa
101. OPE 9400AWPOT Averaging Summation and Continuous Arithmetic including Addition Subtraction and Multiplication Functions including Integration Differentiation and Square Root Extrema Mode Storage of Extreme Positive and Negative Values Smoothing Reduction of Noise on Single Events haining different mathematical functions together the WPO T waveform processing package erform complex measurement sequences with ease Above a damped sine wave top is Ered middie and then integrated bottom allowing RMS mesurements to be calculated FOR SIGNAL The LeCroy WP01 Waveform Processing Firmware Package offers powerful routines that extend the use of the 9400A to signal characterization mathe CHARACTERIZATION matical analysis and post processing of single events Ordered as an option or retrofitted WPO1 allows for further extensions of the 9400A s pro AND ANALYSIS cessing capabilities with other firmware packages The LeCroy 9400A provides 175 MHz bandwidth 100 megasamples sec 8 bit ADCs 2 DC accuracy 1 optional 32K memory per channel and up to 192K of waveform storage memory It is fully programmable over RS 232 C or optional GPIB interfaces Plotter drivers enable color archiving via a wide range of digital plotters FEATURES Extensive Signal Averaging Two operation modes Summation averaging up to 1 000 000 waveforms Continuous averaging with weighting fact
102. RY C to ON by pressing push button 47 II Storage of CHAN 2 Waveform into Memory D Apply a second signal as in Section 8 3 from your pulse generator to CHAN 2 BNC connector 21 Procedure 1 Press STORE push button 1 to call the Store Trace menu 2 Store CHAN 2 into Memory D 5 Basic 9400A Waveform Measurements and Operating Procedures 8 10 3 Set CHAN 2 to OFF 49 4 Set MEMORY D to ON 47 5 Set DUAL GRID to ON by pressing push button 14 6 Select Memory D by pressing SELECT push button 44 7 Adjust VERT GAIN control 42 and Vertical POSITION control 40 to center the trace The above procedure enables two independent waveforms to be simultaneously stored and displayed Calling the Memory Status menu 3 enables the user to review all the acquisition parameters Note that instead of storing the currently acquired CHAN 1 waveform into Memory C and CHAN 2 waveform into Memory D the Store Trace menu also allows the user to inverse this configuration and to store the CHAN 1 waveform into Memory D and the CHAN 2 waveform into Memory C Redefinition Function Expand Memories C D As mentioned in Section 5 2 4 the default signal sources for Expand A and B are CHAN 1 and 2 respectively It is possible however to expand a waveform stored in reference Memories C and or D by redefining these memories to be the new signal expansion source I Expansion of MEMORY C with EXPAND A Just as Expan
103. S ON ERROR GOTO 575 TRUE 1 FALSE 0 LOOP TRUE EXIT FALSE ECHO TRUE STORE FALSE CPRMS t OPEN COM1 9600 N 8 1 AS 1 OPEN SCRN FOR OUTPUT AS 2 PRINT 2 SAMPLE INTERACTIVE PROGRAM FOR LINKING THE LECROY 9400A DSO TO AN PRINT 2 IBM PC AT VIA THE RS232C ASYNCHRONOUS COMMUNICATIONS INTERFACE PRINT 2 nn PRINT 2 Settings 9600 Bd no parity 8 bits 1 stop bit PRINT 2 PRINT 2 Commands XS STRINGS 15 32 PRINT 2 XS REM Remote LOC s Local PRINT 2 XS STORE Store to disk RECALL Retrieve from disk PRINT 2 XS Any valid command described in the User s Manual PRINT 1 CHRS 27 PRINT 1 CHLP PPO PRINT 1 CTRL OFF PRINT 1 CFMT L BYTE UNSIGNED SHORT PRINT 1 CBLS 70 PRINT 1 MASK 6 1 Enable STB 1 PRINT 1 RS CONF 6 13 0 0 0 lt ACK gt lt CR gt PRINT 1 CPRM CHRS 34 CPRMS CHRS 34 WHILE LOOP PRINT 2 LINE INPUT Enter command EX gt exit CS IF LEN CS lt 2 THEN 245 IF CS EX THEN LOOP FALSE GOTO 285 IF CS REM THEN CS CHRS 27 R IF CS LOC THEN CS CHRS 27 L IF CS STORE THEN GOSUB 380 GOTO 285 IF CS RECALL THEN GOSUB 460 GOTO 285 IF CS lt gt THEN PRINT 1 CS GOSUB 300 WEND CLOSE SYSTEM U SUBROUTINE GET STRING FROM DSO f ON TIMER 2 GOSUB 595 TIMER ON CYCLE TRUE WHILE CYCLE PRINT 1 CHRS 6 Basic 9400A Waveform Measurements and Operating Procedures 8 16 33
104. S CONF 9 13 10 0 1000 with a turnaround delay of 1 second The turnaround delay is given in msec therefore the value of 1000 corresponds to 1 sec Note that during this delay the 9400A may appear as dead In the second case i e when the controller echoes characters the 9400A can be configured with the following sequence of commands lt ESC gt disables echoing of characters received by the 9400A COMM TRAILER OFF disables trailer RS CONF 9 13 10 10 0 selects half duplex mode with lt TAB gt decimal9 as trigger or talk character lt CR gt lt LF gt decimal 13 and 10 as lt END gt message string lt LF gt as echo character and no turnaround delay Whenever the controller interrogates the 9400A to get one or several responses or to get one or more blocks of data it sends the command followed by lt CR gt optional and lt LF gt and then by lt TAB gt This last character instructs the 9400A to send one response or one block of data To get more information or more blocks lt TAB gt must be re sent Example The computer wants to get the setup configuration If the 9400A has been configured to sends blocks of data in hex format in blocks of 300 characters the computer will receive 3 blocks Computer sends SU lt CR gt lt LF gt lt TAB gt 9400A answers ere lt CR gt lt LF gt Each character including lt LF gt will be echoed by the computer Computer sends lt TAB gt 9400A answers P a ee lt CR gt
105. SO A4 US 11 x 8 5 ISO A3 US 17 x 11 or non standard In the case of non standard paper sizes the size of the grid square can be chosen between 0 to 99 9 mm in 0 1 mm steps lower left corner position from O to 999 mm for both X and Y coordinates in 1 mm steps If GPIB is selected by no GPIB board is installed basic 9400A the instrument may lock up when the screen dump button is pressed Manual Operation 6 1 6 2 6 3 6 4 SECTION 6 REAR PANEL CONTROLS AND CONNECTORS Fuse Protection The power supply of the 9400A is protected against short circuits and overload by means of a T slow 1 6 250 V fuse for units which can operate on 220 V or 115 V mains voltage switch selected or a T slow 3 15 250 V fuse for units operating only on 115 V mains voltage The fuse is located under the 115 to 220 V mains voltage selector drum cover Accessory Power Connectors 51 Two LEMO RA 0304 NYL connectors have been provided to permit use of FET type probes with the 9400A These connectors provide output voltages of 5 V 15 V and GND connection suitable for most FET probes The maximum output current per connector must be limited to 150 mA for each of the three voltages Battery Pack 52 The battery pack consists of two KR 15 51 1 2 V rechargeable NiCd batteries enabling retention of front panel setups for 6 months in case of power failure or whenever the 9400A is switched off The battery pack is automatical
106. T INS lt FUNCTION E LIMIT FE LI gt E FUNCTION F LIMIT FF LI gt instructs the 9400A to return a character string containing the lower and upper address limits of the current waveform or INSPECT INS lt FUNCTION E NSWEEPS FE NS gt lt FUNCTION F NSWEEPS FF NS gt instructs the 9400A to return a character string containing the number of acquired sweeps in averaging and extrema or INSPECT INS lt FUNCTION E INTVAL FE IV gt lt FUNCTION F INTVAL FF IV gt WPO1 Waveform Processing Option 10 8 3 instructs the 9400A to return a character string containing the interval between data points used by a waveform processing function This value may be used as the lt intval gt parameter in the readout of such waveforms if the user wishes to read only the computed data points and none of the re interpolated points REDEFINE RDF Instructs the 9400A to report the current configuration of the SELECTed trace or REDEFINE RDF AVERAGE AVG SUMMED lt maxpts gt lt source gt lt maxswps gt lt reject gt lt dither gt configures the SELECTed trace for a summed average or REDEFINE RDF AVERAGE AVG CONTINUOUS CONT lt maxpts gt lt source gt lt weight gt configures the SELECTed trace for a continuous average or REDEFINE RDF EXTREMA EXTR lt e type gt lt maxpts gt lt source gt lt maxswps gt configures the SELECTed
107. T processing the Max of Points value selected in the menu of the function is ignored Instead the number of points of the frequency domain waveform is used for further processing Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 3 FFT Processing Examples Example spectrum of the 9400A Probe Calibrator waveform 1 2 3 4 5 6 Connect the 9400A calibration signal 976 6 Hz 1 0 V pp square wave to the channel 1 input If you use a xl0 probe select Panel STATUS and adjust the Set Chi Attenuator to x10 Set Channel 1 volts div to 20 mV div for x10 probe AC 1 MQR Set the Channel 1 offset to a value near Q Select a time base of 1 msec div Adjust the triggering conditions as follows Chl AC coupling normal trigger level about 0 div You should obtain a repetitive display of almost 10 periods of a square wave 5 divisions peak to peak Turn on and Select Function E Redefine Function E as follows Function Class Fourier Transform Display Type Magnitude Transform Size 1250 Source Trace Chan 1 Window Type Rectangular Multiplication Factor 1 00 Additive Constant 0 00 div Zero Suppression ON Notice that at the bottom of the menu page the effective number of points N 1250 and the Nyquist frequency 62 5 kHz are displayed Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 4 7 8 9 10 Start computing the FFT press either Return or
108. a point This case occurs in interleaved sampling at 0 5 pusec div left edge 5 ps div interleaved of screen La e e lann 0 1000 25000 digitized displayed record 24000 pts 4 8 ps missing data on displo As the data record limits depend on the time base and on the acquisi tion mode the 9400A allows the user to read these address limits with the command INSPECT xx LIMIT The response is a data block of 2 16 bit words corresponding to the lowest and the highest address of the data record in question If the user specifies larger limits than valid the 9400A automatically replaces them with the legal ones and sets the VALUE ADAPTED bit in the Main Status Byte STB 1 Interpretation of Waveform Data Values The conversion of the integer waveform data into volts requires the use of three scale and offset parameters found in the descriptor see Section 7 7 Fixed gain transmitted as an 8 bit BYTE at address O relative to the beginning of the descriptor This coded value can be transformed into a number of VOLTS DIV with a user defined table This transformed value is called gain in the formula Variable gain transmitted as an 8 bit BYTE at address 1 relative to the beginning of the descriptor This value is called vgain in the formula belov Offset transmitted as a 16 bit signed WORD at address 4 relative to the beginning of the descriptor This value is called offset in the formula below Wave
109. al or manual trigger and set to provide a 100 nsec wide pulse with an amplitude of your choice 1 Connect signal source to CHAN 1 input 21 2 In the Main Menu press the Recall PANEL push button 5 Basic 9400A Waveform Measurements and Operating Procedures 8 3 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Recall the Default panel setup 9 Return to the Main Menu by pressing the Return push button 10 Call the Panel Status menu 2 Set CHAN 1 Fixed VOLTS DIV as appropriate 27 to match the generator Adjust CHAN 1 VAR vernier 28 as appropriate to match the generator Set CHAN 1 OFFSET as appropriate Set CHAN 1 COUPLING to DC 50 Q Adjust TRIGGER DELAY control 34 to 20 0 Pre Adjust TRIGGER LEVEL control 33 to 00 division Set TRIGGER COUPLING to AC 30 Set TRIGGER SOURCE to CHAN 1 23 Set TRIGGER SLOPE to POS 25 Arm the trigger by setting the TRIGGER MODE 29 to single Set TIME DIV control 36 to 50 nsec div 36 Set INTERLEAVED SAMPLING to OFF 37 Set BANDWIDTH LIMIT to OFF 50 Return to the Main Menu by pressing the Return push button 10 Set CHAN 1 to ON and CHAN 2 to OFF 49 Set DUAL GRID mode to OFF 14 Now trigger the signal source Resulting Display T n A Oe E S N N O O gat ATSA SETUP Plotter Ch1 gt 1 Y Merw OFF T div EU na Ch2 EU ny Trig OOdiv CHAN i Figure 8 3 Basic 9400A Waveform Measuremen
110. al value is 34 Remote Operations 7 33 7 6 8 7 COMM PROMPT CPRM lt OFF gt lt prompt string gt Defines the 9400A prompt string which may be up to 10 characters long The default is OFF This feature simplifies interactive programming of the 9400A When set the host computer must read the 9400A after every command even when no response is normally expected The 9400A responds either with the prompt string alone or with its response followed by the prompt indicating that it is ready for another command Summary of COMM default values COMM HEADER SHORT COMM TRAILER CRLF COMM HELP OFF COMM FORMAT GPIB A format BYTE RS232 L format BYTE UFIX COMMA COMM BLOCKSIZE 0 COMM STRDELIM Decimal value 34 COMM PROMPT OFF Status Byte and Mask Register Commands The 9400A contains a Main Status Byte STB 1 and 5 additional status bytes numbered from 2 to 6 Each status byte has an associated mask register also numbered from 1 to 6 The purpose of the status bytes is to keep track of the internal conditions of the 9400A The user can use 2 methods of staying informed The status bytes can be read at any time one by one or ina single block with or without simultaneous clearing This method ignores all mask registers The host computer program is required to continue testing a status bit of interest e g bit 0 of the OPERATION COMPLETE status byte STB 5 after the SCREEN DUMP command The user
111. all command sequence and data structure is the same as for queries sending a new setup block to the 94004 Host sends the command SETUP lt END gt to 9400A Host sends the data blocks to the 9400A Each data block is composed of a preamble the data an optional postscript and lt END gt Here the setup data cannot be directly appended to the setup command but must be separated by lt END gt Several block formats are available for read and write they are distinguished from each other by the preamble The command COMM FORMAT selects the format Format A GPIB only binary format no checksum Preamble Abb where bb is the number of data values that will be sent 2 binary bytes Data One binary byte for each 8 bit value two binary bytes for each 16 bit value Postscript None Format L GPIB or RS 232 C ASCII format Preamble L lt count gt where lt count gt is the number of data values that will be sent Data lt data gt where lt data gt are data values in ASCII Postscript None lt count gt and lt data gt are in the same format but do not necessarily have the same number of characters However lt count gt is always treated as a WORD 16 bits whereas lt data gt may be chosen as a BYTE 8 bits or as a WORD The choice of formats see COMM FORMAT command is the following BYTE 8 bits value WORD 16 bits value HEX xx 2 hex digits XXXX 4 hex digits UNSIGNED FIXED nnn 3 decimal
112. alue lt a const gt 9 99 to 9 99 Additive constant Default 0 00 Any value smaller than 0 01 or greater than 9 99 is adapted to the nearest legal value NOTE lt a const gt is interpreted as the number of vertical divisions of lt sourcel gt Whenever a parameter is not specified the default value is substituted Examples RDF AVG SUMMED C2 Configures the SELECTed trace which must be FUNCTION E or FUNCTION F for the summed averaging of CHANNEL 2 with a maximum of 1250 data points over 1000 sweeps By default overflow rejection and dithering are off RDF ARI PRD 2500 C1 MD 2 00 1 00 Configures the SELECTed trace to compute the waveform 2 00 CHANNEL 1 1 div Memory D A maximum of 2500 of data points equidistantly distributed over the screen are to be used REDEFINE FNC INTEG 25000 FE Configures the SELECTed trace which must be FUNCTION F since FUNCTION E is specified as source waveform to compute the integral over the waveform in FUNCTION E using a maximum of 25000 data points Note that the use of 25000 data points implies that all data points on the screen are to be used regardless of the time base setting WPO1 Waveform Processing Option 10 12 10 4 4 The READ commands of Section 7 6 5 have been extended to read FUNCTIONS E and F READ RD lt FUNCTION E DESC FE DE lt FUNCTION F DESC FF DE Vv READ RD lt FUNCTION E DATA FE DA Parameter list gt
113. alues gt lt addr gt lt sweep gt transfer ALL data from the host computer to the indicated memory location of the 9400A This command must be followed by the data blocks in the order descriptor data trigger time s See the READ command for an explanation of lt Parameter list gt In general the 9400A decodes and checks each WRITE command it receives and verifies the optional parameters If it receives a WRITE command for a complete waveform WRITE xx the parameters are only checked after the DESCRIPTOR block has been transmitted If the lt intval gt parameter is not 1 intermediate points will be computed with a linear interpolation DESCRIPTOR values are checked for consistency after the entire block has been received If an error is detected the entire block is discarded and the invalid data block has no effect on the currently stored descriptor The same is true for the time block However the waveform DATA values are directly stored into the final buffer during transmission If an error occurs during the transfer the data memory might be only partially filled with the new data The 9400A sets the VALUE ADAPTED bit if a numerical parameter had to be modified during checking if less or more DATA values have been received than were indicated by the numerical parameters after checking and only if the number of DATA values is not greater than the number of values remaining until the end of the sweep buffer Th
114. always generates an SRQ when set Service Request in GPIB The Service Request SRQ is a dedicated interrupt line on the GPIB bus The handling of this interrupt is the responsibility of the user s GPIB driver on the host computer The driver may allow the linking of a user written service routine to the interrupt The GPIB protocol allows an alternative way of reading the Main Status Byte STB 1 through the Serial Poll The execution of the serial poll is again a GPIB driver routine on the host computer Normally the value of STB1 is identical whether it is read by Serial Poll or with the explicit read command STB 1 A difference occurs however when more than one condition occurs that may set the RQS bit Remote Operations The Main Status Byte STB 1 as read with STB 1 keeps accumulating further bits as they get set The Main Status Byte STB 1 as read with the Serial Poll only shows the bits that were set at the time the RQS was set Any bits that should get set due to subsequent events are not taken into account but are remembered until a Serial Poll reads STB 1 and clears it at this point in time any remembered bit is set in STB 1 and may again generate an SRQ The principle in Serial Poll is that SRQ may be generated by one event at a time Example MASK 1 48 Sets the mask of the Main Status Byte STB 1 to the binary value 00110000 allowing the ERROR bit or the OPERATION COMPLETE bit to genera
115. and Concepts Prentice Hall Inc Englewood Cliffs N J 1985 Practice oriented many examples of applications Fast Fourier Waveform Processing Option WPO02 V 2 06FT 11 29 11 10 Index of Topics Paragraph Topic 11 6 Aliasing 11 6 Coefficients of window functions in tabular form 11 6 Coherent gain b P 3 2 Computation of dBm power spectrum et ae Computation of magnitude 115 2 Computation of real imaginary parts 1 R Computation speed of FFT 11 4 2 Description of additional values of FFT descriptors 11 4 1 Description of remote FFT commands 11 6 Equivalent Noise Bandwidth ENBW 11 7 Error and warning messages 11 5 FFT processing application hints 11 4 1 FFT processing description of remote control commands 11 3 FFT processing examples 11 5 1 FFT processing practical rules for using FFT processing 11 5 2 FFT processing steps involved in calculating the FFT 11 6 FFT 9400A Glossary 11 6 Filters 11 6 Frequency bins 11 6 Frequency range 11 6 Frequency resolution 11 6 Leakage 11 2 Modification to WPO1 functions 11 6 Number of points used for computing the FFT 11 6 Nyquist frequency 11 8 Nyquist frequency table 11 6 Picket fence effect 11 6 Power spectrum 11 6 Power density spectrum i Processing capabilities of FFT option 11 9 References 11 6 Sampling frequency 11 6 Scallop loss 11 6 Window frequency domain parameters in tabular form 11 6 Window functions Fast Fourier Waveform Processing
116. are capacitively coupled DC levels are rejected and frequencies below 60 Hz are attenuated LF REJ Signals are coupled via a capacitive high pass filter network DC is rejected and signal frequencies below 50 kHz are attenuated The LF REJ trigger mode is used whenever triggering on high frequencies is desired HF REJ Signals are DC coupled to the trigger circuit and a low pass filter network attenuates frequencies above 50 kHz The HF REJ trigger mode is used when triggering on low frequencies is desired DC All of the signal s frequency components are coupled to the trigger circuit This coupling mode is used in the case of high frequency bursts or where the use of AC coupling would shift the effective trigger level Trigger LEVEL 33 Adjusts the level of the signal required to gener The t SLOPE circu ate a trigger rigger range is as follows 5 screen divisions with CHAN 1 or CHAN 2 as trigger source None zero crossing with LINE as trigger source 2 V with EXT as trigger source 20 V with EXT 10 as trigger source 25 Selects the signal edge used to activate the trigger it POS Requires a positive going edge of the trigger signal NEG Requires a negative going edge Manual Operation 5 7 POS NEG Permits window triggering i e triggering on either a positive or negative going signal edge whichever occurs first When the POS NEG trigger slope is selected the Trigger LEVEL contr
117. c 6 250 MHz 1250 SS 10 usec 6 250 MHz 2500 SS 20 usec 6 250 MHz 6250 SS 50 psec 6 250 MHz 12500 SS 0 1 msec 6 250 MHz 25000 SS 0 2 msec 12 500 MHz 50 SS RIS 0 2 usec 12 500 MHz 125 SS RIS 0 5 msec 12 500 MHz 250 SS RIS 1 wsec 12 500 MHz 500 SS RIS 2 usec 12 500 MHz 1250 SS 5 usec 12 500 MHz 2500 ss 10 usec 12 500 MHz 5000 SS 20 usec 12 500 MHz 12500 SS 50 psec 12 500 MHz 25000 SS 0 1 msec 25 000 MHz 50 SS RIS 0 1 usec 25 000 MHz 100 SS RIS 0 2 usec 25 000 MHz 250 SS RIS 0 5 usec 25 000 MHz 500 SS RIS 1 wsec 25 000 MHz 1000 SS RIS 2 usec 25 000 MHz 2500 SS 5 usec 25 000 MHz 5000 SS 10 usec 25 000 MHz 25000 SS 50 usec 50 000 MHz 50 SS RIS 50 nsec 50 000 MHz 100 SS RIS 0 1 psec 50 000 MHz 200 SS RIS 0 2 usec 50 000 MHz 500 SS RIS 0 5 usec 50 000 MHz 1000 SS RIS 1 wsec 50 000 MHz 2000 SS 2 usec 50 000 MHz 5000 SS 5 usec 50 000 MHz 10000 SS 10 usec 50 000 MHz 20000 SS 20 usec Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 27 Fuyquist Number of SS RIS Time div Points 125 000 MHz 50 RIS 20 nsec 125 000 MHz 125 RIS 50 nsec 125 000 MHz 250 RIS 0 1 usec 125 000 MHz 500 RIS 0 2 usec 125 000 MHz 1250 RIS 0 5 usec 125 000 MHz 2500 RIS 1 usec 125 000 MHz 5000 RIS 2 usec 250 000 MHz 50 RIS 10 nsec 250 000 MHz 100 RIS 20 nsec 250 000 MHz 250 RIS 50 nsec 250 000 MHz 500 RIS 0 1 usec 250 000 MHz 1000 RIS 0 2 usec 250 000 MHz 2500 RIS 0 5 usec 250 000 MHz 5000 RIS ji usec 625 000 MHz 125 RIS 10 nsec 625 000 MHz 250 RIS 20 nsec
118. cale for each trace A cross hair marker measures absolute voltage versus signal ground as well as the time relative to the trigger DIGITAL OSCILLOSCOPE 175 MHz BANDWIDTH 100 Ms s 5 Gs s LeCroy _ MODEL 9400A PORTABLE DUAL CHANNEL OSCILLOSCOPE High Bandwidth and Precision Long Memories High resolution Display Signal Processing and FFT Mass Storage gnal averaging improves the signal to noise ratio and increases sensitivity and vertical resolu in Above a function generator signal is averaged 40 times to show the details of a perturbation top trace THE COMPLETE TEST AND MEASUREMENT SYSTEM The LeCroy 9400A Digital Oscilloscope is a powerful general purpose tool for waveform recording and analysis Combining ease of use with a comprehensive range of measurement and processing capabilities it en ables extremely precise measurements The LeCroy 9400A provides 175 MHz bandwidth 100 megasamples sec 8 bit ADCs 2 DC accuracy 1 optional 32K memory per chan nel and up to 192K of waveform storage memory It is fully programmable over RS 232 C or GPIB interfaces Plotter drivers enable color archiving via a wide range of digital plotters 9400A FEATURES High bandwidth and precision Two independent channels each with 175 MHz bandwidth and a high performance 8 bit ADC handle input signals with better than 2 DC accuracy 1 optional The 9400
119. capable of setting RQS was set in this case the ERROR bit Thus it generates a second Service Request When the host computer executes a second Serial Poll it will read the binary value 01100000 i e the RQS bit and the ERROR bit Upon execution of the second Serial Poll STB 1 will be cleared completely Thus 2 different bits of STB 1 when demasked always generate two different Service Requests provided that STB 1 is read by Serial Poll This follows the principle that SRQ should be generated by one event at the level of STB 1 at a time If the host computer responds by reading the status byte s with STB 1 2 or STB it will read the binary value 01110000 in STB 1 The Main Status Byte STB 1 is cleared and no more Service Requests are generated Thus STB 1 when read explicitly keeps accumulating other status bits and there might be fewer Service Requests than events at the level of STB 1 Another Example MASK 1 32 Sets the mask of the Main Status Byte STB 1 to the binary value 00100000 allowing the ERROR bit to generate an RQS bit i e to generate a service request MASK 6 1 Sets the mask of the ERROR byte STB 6 to a non zero value allowing the propagation of errors to the ERROR bit of STB 1 TIME DIV This legal command generates a response message which can and should be read by the host computer In addition the MESSAGE READY bit is set in STB 1 Because this bit is not demasked it does not generate
120. ce and also controls GPIB IEEE 488 operation when the 9400A is equipped with the I O option OPO2 ADCs and Memories The 9400A s two identical input channels are equipped with a 100 megasample second megasample sec 8 bit ADC and a 32 kiloword acquisition memory See Figure 2 1 This dual ADC architecture ensures absolute amplitude and phase correlation maximum ADC performance for both single and dual channel acquisition modes large record lengths and high time resolution The 9400A s two 32K acquisition memories simplify transient capture by providing very long waveform records that capture waveform features even when trigger timing is uncertain In addition very accurate time measurement is made possible by a digitally controlled zoom providing an expansion factor of up to 100 times the time base speed The 9400A oscilloscope is capable of acquiring and storing repetitive signals at a Random Interleaved Sampling rate of 5 gigasamples second gigasamples sec An exclusive high precision time digitizing technique enables measurement of repetitive signals to a bandwidth of 175 MHz at an effective measuring interval of 200 psec The 9400A s very low aperture uncertainty of 10 psec assures precision measurements over its entire range as indicated by the table below Overall dynamic accuracy typical RMS sine wave curve fit Input Frequency MHz 1 10 50 100 175 Signal to noise Ratio dB 41 9 41 9 41 9 37 1 29 9 Effective b
121. ceded by a leftward pointing arrow in the left hand corner of the Trigger Delay field III ZERO 35 Resets the trigger delay from previously set positions to the leftmost graticule line i e 0 0 Pre trigger position Displaying Traces Up to four different waveforms out of a total of eight may be simultaneously displayed Whenever a trace is displayed by pressing one of the TRACE ON OFF buttons 46 49 the corresponding waveform will appear on the screen together with a short description in the Displayed Trace field V When several signals are being displayed simultaneously buttons 46 49 can be used as convenient trace identifiers by repeatedly pressing one of these buttons and simply seeing which of the displayed traces is turned ON and OFF by this operation EXPAND A B buttons 46 Turn the displayed expansion of a waveform ON or OFF The expanded portion of the waveform is displayed on the source trace as an intensified region The default settings are EXPAND A operates on CHANNEL 1 and EXPAND B operates on CHANNEL 2 They may be changed to allow expansion on any other source trace by using the REDEFINE button 48 MEMORY C D buttons 47 Turn the display of a waveform in reference Memories C or D ON or OFF Acquired data may be stored into these memories via the STORE button 1 as described in Section 5 2 1 FUNCTION E F buttons 48 If your 9400A is equipped with a waveform processing firmware option
122. copes with this option installed see Section 10 which deals with the Waveform Processing Option Screen Adjustments INTENSITY knob 12 Adjusts the intensity of the displayed trace and all alphanumeric readouts and messages The INTENSITY control may be adjusted in either manual or remote control mode GRID INTENSITY knob 13 Controls grid and graticule intensity independently of displayed trace intensity DUAL GRID button 14 This button switches between single and dual grid modes The dual grid is useful when displaying multiple traces in which case the CHAN 1 display is permanently assigned to the upper grid and CHAN 2 to the lower grid All other displayed traces may be repositioned anywhere on the screen via the Vertical POSITION control 40 Manual Operation 5 14 5 1 7 SCREEN DUMP button 11 Dumps the contents of the screen to an on line digital plotter via the 9400A s rear panel RS 232 C interface port or optional GPIB port to provide color or monochrome hard copy archiving of the display All of the screen illustrations included in this manual were produced using the SCREEN DUMP function Cursors Cursor measurements can be made simultaneously on up to 4 traces on the 9400A s CRT MARKER Cursor button 18 Pressing this button generates a cross hair marker for precise time measurements relative to the point of triggering as well as absolute voltage measurements along the displayed waveform i
123. d A and B enabled the user to expand the signals contained in CHAN 1 and 2 Section 8 3 the signals in reference Memories C and or D can be expanded as described below Procedure 1 Store the signal into Memory C as described in Section 8 8 2 Press EXPAND A push button 46 3 Use the Vertical POSITION knob to separate the traces on the screen 4 Set CHAN 1 to ON 5 Press SELECT push button 44 to frame the X Chan 1 message 6 Press REDEFINE push button 45 7 Press push button 4 to define Memory C as the new signal source for Expand A From this step on the procedure to follow is identical to that described in Section 8 3 for CHAN 1 2 expansion steps 3 through 6 II Expansion of Memory D with Expand B The procedure used here is identical to that detailed above except that Expand B is substituted for Expand A in Step 1 and Memory D is redefined as the new source for expansion Step 4 Basic 9400A Waveform Measurements and Operating Procedures 8 11 8 10 It is possible while studying these reference waveforms to simultaneously acquire signals via the CHAN 1 and CHAN 2 acquisition memories in real time Note that you cannot display more than 4 traces on the 9400A s screen at any time Auto store in Memory C D As mentioned in Section 5 2 5 pressing the Special Modes push button 7 permits the user to automatically store the current CHAN 1 and or CHAN 2 display into the unit s two 32K reference me
124. d as members of adjacent bins each containing N1 N2 data points Nl is the number of data points in the source waveform whereas N2 is the number of data points specified by the third line of the setup menu The data points within each bin are averaged resulting in a waveform consisting of N2 data points For readout and display this reduced record is then re expanded to the original number of data points by linear expansion WPO1 Waveform Processing Option 10 6 3 point smoothing consists of computing each data point of the source waveform according to the formula W i 1 W i W i 1 Y i 2 4 where W i is the jth point of the source waveform and Y i is the jth point of the computed waveform If the maximum number of data points specified in the third line of the setup menu is smaller than the original number of points the smoothing is applied to the reduced data record 5 point smoothing consists of the application of 3 point smoothing twice in sequence Similarly 7 point and 9 point smoothing are computed by applying 3 point smoothing 3 and 4 times The resulting averaging formula for 5 point smoothing is W i 2 W i 1 WCi 6 W i l W i 2 m 16 4 16 4 16 Y i Whereas for 7 point smoothing it is W i 3 W i 2 6 WCi 1 15 WCi 20 W i 1 15 64 64 64 64 64 Y i W i 2 6 W i 3 64 64 And for 9 point smooth
125. d must be followed by the descriptor block s The 9400A checks the limits of each parameter transmitted If any value is out of range or the number of values transmitted is incorrect the entire descriptor block is considered invalid and is discarded WRITE WT lt MEMORY C DATA MC DA gt lt Param list gt lt MEMORY D DATA MD DA gt lt Parameter list gt lt intval gt lt values gt lt addr gt lt sweep gt transfer data values from the host computer to the indicated memory location of the 9400A This command must be followed by the data value block s See the READ command for an explanation of lt Parameter list gt or WRITE WT lt MEMORY C TIME MC TI gt lt MEMORY D TIME MD TI gt transfer trigger time s from the host computer to the indicated memory location of the 9400A This command must be followed by the trigger time block If the number of values transmitted is incorrect the entire block is discarded When transferring WRITE DATA without specifying the number of data values the nominal number 1 data values must be sent to the 94004A 25000 1 data values for example This additional value may be needed for the generation of the last displayed point at the right hand side of the screen or WRITE WT lt MEMORY C MC gt lt Parameter list gt lt MEMORY D MD gt Remote Operations 7 27 lt Parameter list gt lt intval gt lt v
126. d trademark of LeCroy Corporation All rights reserved Information in this publication supersedes ail earlier versions Specifications subject to change without notice TDS 011 004 LeCROY CORPORATE HEADQUARTERS 700 Chestnut Ridge Road Chestnut Ridge NY 10977 6499 Telephone 914 425 2000 Greece Hellenic S R Ltd 01 721 1140 India Electronic Ent 02 4137096 Israel Ammo 03 453157 Italy LeCroy Srl Roma 06 302 9646 Milano 02 2940 5634 Japan Toyo Corp 03 279 0771 Korea Samduk Science amp Ind Ltd 02 468 04914 Mexico Nucleoelectronica SA 905 5693 6043 New Zealand E C Gough Ltd 03 798 740 Norway Avantec AS 02 630520 Portugal M T Brandao Lta 02 691116 Spain Anadig Ingenieros SA 01 433 24 12 Switzerland LeCroy SA 022 719 21 11 Sweden MSS AB 0764 68100 Taiwan Topward El Inst Ltd 02 601 8801 United Kingdom LeCroy Ltd 0235 33 114 ae LeCROY EUROPEAN HEADQUARTERS 2 rue Pr de la Fontaine P O Box 341 1217 Meyrin 1 Geneva Switzerland Telephone 022 719 21 11 Telex 41 90 58 Fax 022 782 39 15 a es i Chonnel 2 l l 2ys gt 1 V Chi SU my 7 T div 2ps Ch2 gt 1 Y lt Trig 36div CHAN 2 In single shot applications the 9400A s smoothing routines can be used to remove high frequency noise from transients MASS STORAGE 9400AMS01 Optional dual floppy disk storage system mounted externally on the oscilloscope
127. data received with a WRITE descriptor command Command not yet implemented 1 to 6 x 7 Reads the contents of one of the 6 status bytes and clears it STB1 is the Main Status Byte STB 4 is not cleared or STB l 7 Reads all 6 status bytes in the order 1 to 6 and clears them except STB 4 Remote Operations 7 37 7 6 9 2 3 MASK 1 to 6 J l 7 Reads the contents of one of the 6 mask registers Mask register 1 is the mask register corresponding to the Main Status Byte or MASK Reads the contents of the 6 mask registers in the order 1 to 6 or MASK 1 to 6 O to 255 Sets the contents of one of the 6 mask registers to a decimal value between 0 to 255 TSTB 1 to 6 A Reads the contents of one of the 6 status bytes but does not clear it Status Byte 1 is the Main Status Byte or TSTB Reads the contents of all status bytes in the order 1 to 6 but does not clear them GPIB Interface Message Interpretation 1 2 3 Device clear DCL GPIB hexa code 14 or SDC GPIB hexa code 4 Clears the input and output buffers terminates plotting and data transmission All the status bytes except STB 4 and all the corresponding masks as well as the SRQ line are reset THIS COMMMAND IS IMMEDIATELY EXECUTED Trig GET GPIB hexa code 8 Re arms the oscilloscope Valid only in SINGLE or SEQNCE mode and only when the 9400A is in REMOTE REMOTE LOCAL commands If th
128. defined FFT is computed on this partially undefined record You should avoid stopping the acquisition in this manner if you wish to obtain meaningful FFT results WARNING FFT src wfm over underflovw The source waveform has been clipped in amplitude either in the acquisition too high gain or inappropriate offset or in the previous processing The resulting FFT contains harmonic components which were not present in the unclipped waveform You should repeat the acquisition or previous processing of the source waveform with changed settings Table of Nyquist Frequencies F Number of SS RIS Time div Nyquist Points 25 000 mHz 50 SS 100 sec 62 500 mHz 125 SS 100 sec 0 125 Hz 50 SS 20 sec 0 125 Hz 125 SS 50 sec 0 125 Hz 250 SS 100 sec Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 22 Fuyquist Number of SS RIS Time div Points 0 250 Hz 50 SS 10 sec 0 250 Hz 100 SS 20 sec 0 250 Hz 250 SS 50 sec 0 250 Hz 500 Ss 100 sec 0 625 Hz 125 SS 10 sec 0 625 Hz 250 SS 20 sec 0 625 Hz 625 SS 50 sec 0 625 Hz 1250 SS 100 sec 1 250 Hz 50 Ss 2 sec 1 250 Hz 125 ss 5 sec 1 250 Hz 250 SS 10 sec 1 250 Hz 500 SS 20 sec 1 250 Hz 1250 Ss 50 sec 1 250 Haz 2500 SS 100 sec 2 500 Hz 50 ss 1 sec 2 500 Hz 100 SS 2 sec 2 500 Hz 250 SS 5 sec 2 500 Hz 500 SS 10 sec 2 500 Hz 1000 SS 20 sec 2 500 Hz 2500 Ss 50 sec 2 500 Hz 5000 SS 100 sec 6 250 Hz 125 SS 1 sec 6 250 Hz 250 SS 2 sec 6 250 Hz 625 SS 5 sec 6 250 Hz 1250 SS 10 sec 6 250 Hz
129. digits nnnnn 5 decimal digits UNSIGNED SHORT n 1 to 3 decimal digits nnnnn 1 to 5 decimal digits Remote Operations 7 9 The HEX and UNSIGNED FIXED are fixed size formats whereas UNSIGNED SHORT is a variable size format Therefore it requires commas to separate the values Examples HEX format LO00A0102030405060708090A UNSIGNED FIXED L 10 1 2 3 4 5 6 7 8 9 10 Each dot repre sents a space character UNSIGNED SHORT L 10 1 2 3 4 5 6 7 8 9 10 Note The conversion type and the size must be fixed before reading AND writing data Data transfers via RS 232 C can only be made in ASCII formats If the host computer allows only small amounts of data to be sent or read the transfer may be partitioned into several blocks of the selected format The maximum length of each block is determined by the COMM BLOCKSIZE command The length includes all bytes or characters of the block as well as characters which may compose the lt TRAILER gt and ENDS The transfer will be structured as follows 15t Block lt TRAILER gt lt END gt 2 Block lt TRAILER gt lt END gt Last Block lt TRAILER gt lt END gt END block lt TRAILER gt lt END gt Where the END block is I When reading data from the 9400A the exact form of the TRAILER is determined by the command COMM TRAILER lt END gt is lt END gt lt CR gt when using RS 232 C unless modified with the command RS
130. downwards with 2 Hz resolution X CFFTC2 X CFFT 2 2 MHz 10 mv X CFFT 2 2 MHz 10 mV TOE LLES Ch 1 2Omv T div 20 us Ch2 gt 50 mV Trig 1 56 div CHAN 2 Chi 20mY 7 T div 20 ps Ch2 gt 20 my Trig 1 56 div CHAN 2 A 2 MHz signal is frequency modulated with a 99 kHz sine wave To Long records allow higher sampling rates to reduce aliasing A improve the signal to noise ratio on the phase incoherent FM signal 110 kHz square wave is recorded over 1250 and 6250 points with spectral averaging of 64 spectra is used bottom trace The part of sampling rates of 200 and 40 nsec point respectively The bottom the spectrum at the right hand side is the 2nd harmonic of the carrier trace a short record transform has considerable aliasing whereas with sidebands the longer record transform top is alias free Definition of Function E Function Clase Fourier Transform Display Type Power Density Max Points Source Trace Chan 2 Window Type Hann ing Multiplication Factor 1 00 Additive Constant Zero Suppression Function E FFT Chon 2 for 25000 pnts Nyquist 625 MHz The FFT menu documents all the relevant parameters LeCROY CORPORATE HEADQUARTERS LeCROY EUROPEAN HEADQUARTERS 700 Chestnut Ridge Road 2 rue Pr de la Fontaine Chestnut Ridge NY 10977 6499 P O Box 341 Telephone 914 425 2000 1217 Meyrin 1 Geneva Switzerland y TWX 710 577 2832 Telephone 022 719 21
131. dwidth and 9400A 175 MHz bandwidth oscilloscopes LeCroy have published the following application notes which are available on request ITI 002 Linking the LeCroy 9400 to an IBM PC AT via the RS 232 C Asynchronous Interface ITI 005 Linking the LeCroy 9400 to an IBM PC AT via GPIB ITI 006 Linking the LeCroy 9400 to an HP 9000 Model 216 controller RS 232 C Ports 56 and 5 7 The 9400A has two RS 232 C ports One is available for computer or terminal controlled oscilloscope operation the other for plotter interfacing The RS 232 C ports provide an asynchronous data transfer rate of up to 19 200 baud Remote Operations 7 1 7 3 RS 232 C Pin Assignments The remote RS 232 C pin Assignments indicated on the rear panel are as follows Pin Description 2 TxD Transmitted Data from the 9400A 3 RxD Received Data to the 9400A 4 KTS Request To Send always on from the 9400A 5 CTIS Clear To Send to the 94004A When TRUE the 9400A can transmit When FALSE transmission stops It is used for the 9400A output hardware handshake 20 DTR Data terminal ready from 9400A If the software Xon Xoff handshake is selected it is always TRUE Otherwise hardware handshake it is TRUE when the 9400A is able to receive characters and FALSE when the 9400A is unable to receive characters 6 DSR Data Set Ready to the 94004A 1 GND Protective Ground 7 SIG GND Signal Ground This corresponds to a DTE Data Terminal Equipment c
132. dy accumulated extrema waveform Whenever a given data point of the new waveform exceeds either positively or negatively the corresponding data point of the accumulated extrema waveform it replaces the former value in the extrema waveform Thus a maximum called roof or a minimum called floor envelope of all waveforms is accumulated Whenever the maximum number of waveforms is reached the accumulation process stops The accumulation process may be interrupted by switching the trigger mode from NORM to SINGLE 29 or by turning the function trace OFF 48 Accumulation will continue when these actions are reversed The currently accumulated extrema waveform may be reset by either changing an acquisition parameter such as input gain offset or coupling trigger condition or the time base or by pressing the RESET push button 41 twice in quick succession remember that FUNCTION E or F must be selected The number of currently accumulated waveforms is displayed in the Displayed Trace Field V in Figure 4 1 of the corresponding function or of its expansion Whenever the maximum number of sweeps is reached a larger number of sweeps may be accumulated by simply changing the maximum number of sweeps in the setup menu In this case care must be taken to leave the other parameters unchanged otherwise the extrema calculation is started again WPO1 Waveform Processing Option 10 5 10 2 4 10 2 5 10 2 6 Extrema may be performed ove
133. e 6669666466668 6646666866666 DT LAAL UI E E PET TTT 6666666646 E PF HHT 0006808008086 00000680080808 6666668644686 gt e TTT TTT l L J P IIEKI PTT 0000806290808 eeeeeeeeene 6669666666966 PTT D 020000080288 eeeoesoeneeee eo THH HT H aes ee 5 E R T 6666866666666 TH G PETIT 6666666964666 e02ee00e00888 TAYTLI k e A w h a d o A wR C5 at TES U L Pr E IL OAS FRAVPD De va FPS SOPH Hs pra PF AAP t SNA REN er LK KPE aE HD cha 55 56 57 54 53 52 51 9400A REAR PANEL Figure 1 2 For instant hard copies the 9400A s screen dump feature sends data directly to the DP9001 8 pen digital plotter ORDERING INFORMATION Oscilloscope and Options Code Description 9400A G Digital Oscilloscope 9400AOP01 High precision Option 9400AOP03 Printer Option for 9400A G 9400AWP01 Waveform Processing Option 9400AWPO02 FFT Processing Option requires 9400AWP01 9400AMS01 Mass Storage and Remote Control Package in cluding an IBM lap top controller interface cables and software 9400AIM01 GPIB Interface for IBM PCC computers 9400CS01 Calibration Software Oscilloscope Accessories OM9400A SM9400A Operator s Manual Service Manual sas a Ps EREN Bg at ti Cah AE NC MM AA AD A wide range of oscilloscope accessories including cameras and a scope cart pictured are available for the 9400A Oscilloscope Accessories con
134. e 9400A receives a command to go into REMOTE or go back to LOCAL while it is acquiring a signal the front panel REMOTE LED doesn t change although the internal state as well as the display will change Remote Operations 7 38 RS 232 C Only Commands The following commands are only valid when the 9400A is controlled via the RS 232 C ports lt ESC gt stands for the ASCII ESCAPE character 1 RS_ CONF lt duplex gt lt endl gt lt end2 gt lt echo gt lt delay gt Configures the RS 232 C remote control protocol O to 127 If 0 it selects full duplex mode otherwise selects half duplex mode The number represents the decimal ASCII value of the trigger or talk character lt duplex gt O to 127 0 to 127 Selects lt END gt message string of 1 or 2 characters in length as it will be used in commands sent to the 9400A In transfers from the 9400A to the host computer messages or data blocks are terminated with lt TRAILER gt as defined with the command COMM TRAILER followed by lt END gt Default lt CR gt lt endl gt lt end2 gt O to 127 Selects the echo character in half duplex only If zero no echo mode is selected Default no echo character lt echo gt O to 60 000 Selects the delay before talk in msec half duplex only Default O msec lt delay gt The 9400A sets the VALUE ADAPTED bit if an out of range positive value is given for the delay The 9400A may
135. e 9400A sets the INVALID BLOCK ERROR if an error in a block has been detected i e if The preamble is incorrect is not A L or 1 The preamble number indicating how many values the block has is greater than the number of values that are allowed SETUP DESCRIPTOR or TIME or greater than the number of values remaining until the end of the sweep buffer DATA The number of received values does not correspond to the number in the preamble In the case of ASCII blocks L format there are characters which are neither separator characters CR or LF nor digits In the case of ASCII blocks a value is greater than 255 BYTE or 8 bits transfer or greater than 65535 WORD or 16 bits transfer Other errors Too many or too few values have been received SETUP DESCRIPTOR or TIME Remote Operations 7 28 READ CHANNEL 2 32000 Instructs the 9400A to transmit the waveform descriptor data and time s of Channel 2 including all invisible data values on the left hand side of the screen The address 32000 is usually out of range but the 9400A automatically adapts to the closest legal value This complete data record is restored in memory C with the command WRITE MC 32000 5 WRITE WT lt MEMORY C DESC MC DE gt lt MEMORY D DESC MD DE gt k transfer the waveform descriptor from the host computer to the indicated memory location of the 9400A This command must be followed by the
136. e waveform to be displayed If you select the Real Part or Imaginary Part Display Type no further computation is done the displayed waveform is R or I as defined above If you select Magnitude mode the magnitude is computed as M R 4I n n n In practice the steps described above lead to the following result An AC sine wave of amplitude 1 0 V and an integral number of periods in the time window transformed with the rectangular window results in a fundamental peak of 1 0 V magnitude in the spectrum However a DC component of 1 0 V transformed with the rectangular window results in a fundamental peak of 2 0 V Magnitude in the spectrum The displayed waveforms for the other available modes are computed as follows Phase angle arctan L R v 9 Main angle 0 M lt Min where M is the minimal magnitude fixed at about 1073 of the full scale i e 64 units on the scale of 65536 16 bits at any gain setting Fast Fourier Waveform Processing Option WPO2 V 2 06FT 11 14 11 5 3 dBm Power Spectrum M M n n Log PS 10 log 20 log n 10 M 10 N ref ref where M var 0 316 V that is O dBm is defined as the sine wave of 0 316 V peak or 0 224 V RMS giving 1 0 mW into 50 Q amp Q Note that the dBm Power Spectrum could also be called the dBm Magnitude as suggested by the formula above dBm Power Density Log PD log PS 10 log ENBW Af n n 10 where EN
137. ed for both CHAN 1 and CHAN 2 signal inputs as well as the external trigger connector The maximum permissible input voltage is 250 V DC peak AC Signal Coupling and Input Impedance 22 Selects the method used to couple a signal to the vertical amplifier input Possible selections AC GND or DC with 1 MQ impedance DC with 50 Q impedance In the AC position signals are coupled capacitively thus blocking the input signal s DC component and limiting the lower signal frequencies to lt 10 Hz In the DC position all signal frequency components are allowed to pass through and the input impedance may be chosen to be 1 MQ or 50 Q The user should note that with 1 MQ input impedance the bandwidth is limited to 100 MHz The maximum dissipation into 50 Q is 0 5 W and signals will automatically be disconnected whenever this occurs A warning LED OVERLD lights when an overload condition is detected The input coupling LED 22 is simultaneously switched to GND The overload condition is reset by removing the signal from the input and selecting a 50 2 input impedance again VOLTS DIV 27 Selects the vertical sensitivity factor ina 1 2 5 sequence The sensitivity range is from 5 mV to 5 V div at 1 M amp input impedance and from 5 mV to 1 V div at 50 N impedance when the VAR vernier 28 is in the detent position i e turned fully clockwise Manual Operation 5 1 Main Merw DISPLAY of VERTICAL SENSITIVITY PARAMETERS in the
138. ed to a computer and can later be retrieved and displayed on the 9400A Color Archiving Provides color hard copies of the screen using a wide range of digital plotters 7020202082008 0800660 FFT BRINGS STRONG SPECTRAL ANALYSIS CAPABILITIES TO THE 9400A i H ee Oe nnn POWERFUL PERFORMANCE IN A WIDE RANGE Preventive maintenance systems With a motion OF APPLICATIONS transducer accelerometers velocity and or displacement transducers the 9400AWPO02 package can be used to analyze the vibration signatures of rotating and reciprocating machinery for early detection of wear or damage Non destructive test engineering The high bandwidth and sampling rate of the 9400A together with its long memories make it a valuable instrument w for ultrasound non destructive testing Long record The versatility and performance of the WPO2 FFT package with the 9400A make it an ideal tool for a variety of applications such as Electronic engineering As a very high performance spectrum analyzer it is extremely useful for measuring phase noise characterizing filters amplifier bandwidth roll off or harmonic distortion a Pi isa aan ee bl FFTs provide unprecedented spectral resolution Ee links modems and data links cable hence improved characterization of the material under fiber optics etc test and much shorter measuring times Acoustic devices Covers the entire audio spectrum in one FFT operation from 25 kHz
139. eep gt transfer ALL data from the host computer to the indicated memory location of the 9400A This command must be followed by the data blocks in the order descriptor data trigger time s See the READ command for an explanation of lt Parameter list gt In general the 9400A decodes and checks each WRITE command it receives and verifies the optional parameters If it receives a WRITE command for a complete waveform WRITE xx the parameters are only checked after the DESCRIPTOR block has been transmitted If the lt intval gt parameter is not 1 intermediate points will be computed with a linear interpolation DESCRIPTOR values are checked for consistency after the entire block has been received If an error is detected the entire block is discarded and the invalid data block has no effect on the currently stored descriptor The same is true for the time block However the waveform DATA values are directly stored into the final buffer during transmission If an error occurs during the transfer the data memory might be only partially filled with the new data The 9400A sets the VALUE ADAPTED bit if a numerical parameter had to be modified during checking if less or more DATA values have been received than were indicated by the numerical parameters after checking and only if the number of DATA values is not greater than the number of values remaining until the end of the sweep buffer The 9400A sets the INVALID BLO
140. eft and right of the CRT The oscilloscope displays up to four waveforms while simultaneously reporting the parameters controlling signal acquisition In addition the screen presents internal status and measurement results as well as operational measurement and waveform analysis menus A hard copy of the 9400A s screen is available via the unit s dedicated plotter port Manual and Programmed Control The 9400A s front panel layout and operation will be very familiar to users of analog oscilloscopes The interactive software menus assist in quickly utilizing the recording and processing capability of the 9400A to its full potential Product Description 2 3 The 9400A has also been designed for remote control operation in automated testing and computer aided measurement applications The entire measurement process including dynamic modification of front panel settings and display organization can be controlled via the rear panel RS 232 C and optional GPIB IEEE 488 ports GPIB control enables direct interfacing between the 9400A and a host computer at data transfer rates of up to 400 kilobytes sec The LeCroy 9400A is capable of storing up to seven front panel setups which may be recalled either manually or by remote control thus ensuring rapid oscilloscope front panel configuration When the power is switched on the 9400A s front panel settings are the same as when it was last used Product Description 2 4 1 3
141. ent before the least significant byte In single shot acquisition INTERLEAVED OFF there is a single time value In SEQNCE acquisition there are as many trigger times as there are sweeps The trigger times are transmitted in the order 1 to N where N is the number of sweeps In INTERLEAVED acquisition there are as many trigger times as there are interleaved sweeps making up the acquired trace At 2 usec div there are 25 sweeps at a nominal interval of 800 psec At 1 usec div there are 50 sweeps at a nominal interval of 400 psec At 500 nsec div and below there are 100 sweeps at a nominal interval of 200 psec The times are transmitted in the order O to N 1 where N is the number of sweeps Note that time i 0 lt i lt N corresponds to the data points at address i N i 2N i 3N i etc i e to all data points of a Single sweep Remote Operations 7 47 7 9 In many data analyses the trigger times may be ignored especially if relative time measurements are made In INTERLEAVED acquisition however ignoring the trigger times results in the interleaved sweeps being put on an equidistant timing grid although they are not necessarily equidistant at acquisition This is equivalent to introducing an acquisition jitter of up to a nominal sampling interval i e degrading the apparent dynamic behavior of the ADC Data Addressing Conventions Data values are always addressed in a screen oriented manner Address
142. er Option for 9400A G DP9001 Digital Plotter 8 pen A4 size 9400AWP01 Waveform Processing Option 94XX FC Front Cover 9400AWPO02 FFT Processing Option requires 9400AWP01 0C9001 Oscilloscope Cart 9400AMS01 Mass Storage and Remote Controi Package in P9010 10 1 Oscilloscope Probe cluding an IBM lap top controller interface cables P9010 2 10 1 Oscilloscope Probe with 2 m cable and software P9011 10 1 1 1 Oscilloscope Probe B 9400AIM01 GPIB Interface for BM PCC computers P9100 100 1 Oscilloscope Probe 9400CS01 Calibration Software RM9400 Adapter Kit for Rack Mounting i i SG9001 High voltage Protector Oscilloscope Accessories Set Pench Gace OM9400A Operator s Manual TC9002 Protective Cover SM9400A Service Manual TC9003 Transit Case for 9400A and Mass Storage a US SALES OFFICES 1 800 5 LeCroy automatically connects you to your local sales office WORLDWIDE Australia Scient Devices Pty Ltd 03 579 3622 Austria Dewetron Elektr Messgerate GmbH 0316 391804 Benelux LeCroy B V 31 4902 89285 Canada Rayonics Sci Inc W Ontario 416 736 1600 E Ontario Manitoba 613 521 8251 Quebec 514 335 015 W Canada 604 293 1854 Denmark Lutronic Aps 42 459764 Finland Labtronic OY 90 847144 France LeCroy Sarl 1 69073897 Germany LeCroy GmbH 06221 49162 North 0405 42713 Croy Innovators in Instrumentation TWX 710 577 2832 Fax 914 425 8967 Copyright March 1990 LeCroy is the registere
143. er of points N is displayed at the bottom of the FFT Redefine Menu screen It is always a sub multiple of the number of points actually displayed in the time domain FFT generates N 2 spectrum points as output These points are expanded by linear interpolation to 12500 points 10000 points in the case of 10 MHz div Nyquist Frequency Equal to one half of the total sampling frequency Also f Nyquist Af N 2 In the 9400A the value of Nyquist frequency is displayed at the bottom of the FFT Redefine Menu screen Picket Fence Effect Observe again the Power Spectrum of a sinusoidal waveform having an integral number of periods in the time window i e the source frequency equals one of the bin frequencies using the Rectangular window The spectrum is a sharp peak whose value reflects accurately the source waveform s amplitude For other input frequencies the spectrum peak is lower and broader Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 18 Its highest point can be lower by 3 92 dB 1 57 times when the source frequency is half way between two bin frequencies This variation of the spectrum magnitude is called the Picket Fence Effect the loss is called the Scallop Loss All window functions compensate this loss to some extent but the Flat Top window provides the best correction see Table 11 3 Power Spectrum The Power Spectrum V is the square of the Magnitude spectrum The 9400A displays the
144. eter or a suffix is not recognized A SEMANTIC ERROR is produced when the command is composed of a wrong combination of parameters or if a numerical parameter is not valid An ENVIRONMENT ERROR is produced when the command although it is valid cannot be accepted the 9400A not being in the state to do so When an error is detected the corresponding code is loaded into status byte 6 and the bit 5 of status byte 1 is set Some commands cause bit 0 of status byte 1 VALUE ADAPTED bit to be set when the 9400A detects a numerical value or a parameter out of range The value is always modified to the closest legal value Data Block Transfers Data 9400A setup values waveform values waveform descriptor are transferred between the 9400A and the Host Computer see the READ or SETUP commands Section 7 6 5 or between the Host and the 9400A see WRITE or SETUP commands in one or several blocks Data blocks are never contained within a read or write command but are always separate This section explains only the overall block structure For the interpretation of the data see Section 7 10 Examples Reading a waveform from channel 1 of the 9400A Host sends the command READ CHANNEL 1 DATA lt END gt to 9400A 9400A responds with one or several data blocks in one of the formats described below and terminates with lt TRAILER gt and lt END gt Remote Operations 7 8 A A AMM MM M M M MM M M M M Thus the over
145. followed by one or more parameters used to describe the desired operation in greater detail HEADER lt SPACE gt lt gt or lt gt Parameter 1 Parameter 2 etc Remote Operations 7 4 4 The header may be separated from Parameter 1 by either a space comma equals sign or any combination of these Parameters MUST be separated from one another using a comma Headers and key word parameters may be transmitted using either the full or an abridged format Both upper and lower case characters are valid and may be used interchangeably Numbers must be in accordance with ANSI X3 42 1975 standards and may be transmitted as integers or in scientific notation with or without exponents Waveform data values however can only be transferred as integers 8 or 16 bits Suffixes are optional but acceptable only when specifically mentioned Example The following commands are all legal ways of setting the vertical gain of CHANNEL 1 to 100 mV div CHANNEL 1 VOLT DIV 1 CHANNEL 1 VOLT DIV 100 MVOLT C1VD 100E 03 VOLT C1VD 100 MV The expression lt 100 MV gt is considered as a single parameter witha suffix therefore no comma is allowed to separate them The space separating the parameter value and the suffix is optional Answers from the 9400A As well as specifying a new parameter setting it is also possible to query the 9400A in order to obtain a current value Such queries are always indicated by a question mark
146. form Data in 8 bit Format This is the default format of all data records if the Waveform Processing option is installed it is possible to modify it to 16 bits with the command COMM FORMAT The unsigned 8 bit data values in the numerical range 0 255 are transformed to volts as follows Remote Operations 7 50 data 128 offset 200 200 gain l 32 25 vgain 80 The first expression data 128 32 transforms the unsigned data value to a signed value in units of vertical divisions The second expression offset 200 25 translates the internal coding of the offset into a signed offset units vertical divisions The third expression 200 vgain 80 takes into account the variable gain It reduces to the value 1 when vgain assumes the calibrated value of 120 Examples gain 100 mV byte O of descriptor 26 offset 200 no offset vgain 120 calibrated gain The formula reduces to V 100 mV data 128 32 data volts 0 400 mV 128 O mV 129 3 12 mV 160 100 mV 240 350 mV 255 396 88 mV gain 500 mV byte O of descriptor 28 offset 250 offset 2 div vgain 20 variable gain 900 equivalent to MULTIPLYING the vertical scale by 2 The formula reduces to V 500 mV data 128 32 2 2 0 data volts O 6 0 V 64 4 0 V 128 2 0 V 192 U V 193 31 25 mV 200 25 V 240 1 5 Vy 255 1 969 V Remote Operations 7 51 7 10 2 7 11 7 11 1 Waveform
147. functions can be loaded over GPIB and stored in the 9400A s reference memories Calibrated Vertical Scaling Flattop truncation window provides precisely calibrated vertical scaling for all spectral components Frequency Domain Averaging Averages up to 200 FFT results to reduce base line noise and allows analysis of phase incoherent and non trigqgerable noisy signals Time Domain Averaging Can increase the dynamic range up to 72 dB or more when averaging real time signals prior to FFT execution Offset dithering helps to improve dynamic range and reduces ADC non linearity effects Frequency Cursors Cursors give up to 0 008 frequency resolution and measure power or voltage differences to 0 2 of full scale Automatic DC Suppression DC signal components may be suppressed automatically prior to FFT execution menu selected Full Documentation The 9400A Digital Oscilloscope status in the Frequency Domain is fully documented on one comprehensive display page specifying Nyquist frequency number of points vertical scaling window function etc Chaining of Operations Chains two operations automatically e g Function F FFT of CH1 X CH2 Any number of operations may be performed sequentially either manually or via remote control Full Remote Control All front panel settings and waveform processing functions are programmable via GPIB and or RS 232 C interfaces Acquired and processed waveforms can be download
148. g rare glitches or monitoring signals drifting in time and amplitude is made easy with the unique EXTREMA mode The computation of extrema consists of a repeated comparison of recurrences of the source waveform with the accumulated extrema waveform as 99 Whenever a given data point of the new waveform exceeds the existing data point of the accumulated extrema waveform it replaces it In this way the maxi mum and or minimum envelope of all waveforms is accumulated up to a maximum of 1 000 000 sweeps ARITHMETIC WP01 also offers basic arithmetic operations such as addition subtraction division and multiplication These arithmetic functions can be performed on two source waveforms on a point by point basis Different vertical gains and offsets of the two sources are auto matically taken into account However both source waveforms must have the same time base setting The first waveform may be multiplied by a constant factor and offset by a constant MATHEMATICAL FUNCTIONS Mathematical functions such as negation square square root integral and differentiation are performed on a single source waveform The waveform may be multiplied by a constant factor and may be offset by a constant Arithmetical and mathematical functions may be chained by using memory C and D SMOOTHING WP01 provides two types of smoothing to decrease signal noise of single transient acquisitions SPECIFICATIONS SUMMATION AVERAGING Nu
149. h button 44 and then adjusting Vertical POSITION control 40 To ensure easy display readability repeat this step if necessary selecting X CHAN 2 instead of X CHAN 1 with the SELECT push button 44 Basic 9400A Waveform Measurements and Operating Procedures 8 13 8 12 In the Common Expand mode only the Horizontal POSITION control 39 and the TIME MAGNIFIER control 43 act simultaneously on both the Expand A and B signal source while the VERT GAIN control 42 and the Vertical POSITION control 40 act independently on each expanded waveform When input signals to the 9400A are to be observed at different points in time it is possible to independently adjust the time difference between the two intensified regions prior to calling the Common Expand mode When the Common Expand mode is subsequently called by pressing push buttons 7 and 4 in that order the intensified regions for the two expansion sources may then be magnified by means of the TIME MAGNIFIER control 43 and moved horizontally at a fixed time interval by means of the Horizontal POSITION control 39 The time cursors may be called by pressing push button 17 for high precision measurement of the time interval between the two displayed regions Note that at any time the user may eliminate the time interval separating the intensified regions by pressing RESET push button 41 Remote Control Via the RS 232 C Port The 9400A has been designed to permit c
150. h expanded waveform Note that when the Common Expand mode is called the EXPAND A magnification factor applies to both A and B expansion RS 232 C Setup 8 Two RS 232 C ports are available on the rear panel of the 9400A permitting remote oscilloscope operation and data transfer as well as convenient plotter interfacing Manual Operation 5 26 When in the main menu pressing RS 232 C SETUP button 8 calls an interactive menu enabling configuration of both of the 9400A s RS 232 C ports for a particular application Parameters for the plotter dedicated RS 232 C port 57 are displayed in the lower portion of the screen while those for the remote RS 232 C port 56 are presented in the upper portion of the screen RS232 Remote control port Baud rate 8600 Previous FIELD Character length bits 8 Next Parity none Number of stop bits 1 RS232 Plotter port VALUE Baud rate 9600 Next Character length bits 8 Parity none Number of stop bits 1 Return PLOTTING RS 232 C SETUP MENU Figure 5 16 To modify any of the parameters displayed first select the field to be modified The rectangular frame around parameter values indicates the currently selected field Pressing the Previous FIELD button 2 will cause the frame to move towards the top of the list whereas pressing the Next FIELD button 3 will move the frame downwards Following field selection the current value of the field may be modified by
151. he redefine command has also been extended to accept the parameters related to the FFT Power Average REDEFINE RDF FFT AVG FFTA lt disp_type gt lt nsweeps gt The parameters have the following options lt disp type gt lt POWER_SPECTRUM PWS gt default lt POWER DENSITY PWD gt lt nsweeps gt lt MAGNITUDE AN AN N N 100 200 gt gt gt gt gt MAG gt default Any other number generates a semantic error Fast Fourier Waveform Processing Option WP02 V 2 06FT NOTE This definition can be applied only to Function F It will be executed only if Function E is defined as FFT any display mode The number of points will be that of the output of the FFT i e N 2 Examples RDF FFT MAG 1250 C1 Redefines the SELECTed trace E or F for the FFT of Channel 1 with maximum 1250 points displaying the Magnitude on a linear scale Default settings are applied to the remaining parameters Rectangular window m fact 1 0 a_const 0 0 zero suppression is ON RDF FFT PWS 625 C2 BH 2 0 OFF Redefines the SELECTed trace E or F for the FFT of Channel 2 with maximum 625 points displaying the Power Spectrum on a logarithmic dBm scale Window Type is Blackman Harris m fact 2 0 a_const 0 0 zero suppression is OFF RDF FFTA PWD 20 Redefines the SELECTed trace must be F for the FFT Power Average of the FFT computed simultaneously by Fu
152. he descriptor block s The 9400A checks the limits of each parameter transmitted If any value is out of range or the number of values transmitted is incorrect the entire descriptor block is considered invalid and is discarded WRITE WT lt MEMORY C DATA MC DA gt lt Param list gt lt MEMORY D DATA MD DA gt x lt Parameter list gt lt intval gt lt values gt lt addr gt lt sweep gt transfer data values from the host computer to the indicated memory location of the 9400A This command must be followed by the data value block s See the READ command for an explanation of lt Parameter list gt or WRITE WT lt MEMORY C TIME MC TI gt lt MEMORY D TIME MD TI gt transfer trigger time s from the host computer to the indicated memory location of the 9400A This command must be followed by the trigger time block If the number of values transmitted is incorrect the entire block is discarded When transferring WRITE DATA without specifying the number of data values the nominal number 1 data values must be sent to the 9400A 25000 1 data values for example This additional value may be needed for the generation of the last displayed point at the right hand side of the screen or WRITE WT lt MEMORY C MC gt lt Parameter list gt lt MEMORY D MD gt Remote Operations 7 27 lt Parameter list gt lt intval gt lt values gt lt addr gt lt
153. he display gain not the acquisition gain by a factor of up to 2 5 Remote Operations 7 16 Reduce Signal Size Increase Signal Size Turn the Vert Gain knob Turn the Vert Gain knob anti clockwise clockwise Notice that a gt symbol Notice that the volts value in the window changes e g 5 V changes to gt 2 V Manually appears in the window on 9400A screen Read the exact V div in the memory STATUS menu Read the exact V div in the memory STATUS menu Enter the command VG Query The response is a value between 1 and 2 5 Exact V div response x value indicated in the select window on 9400A screen Remote Enter VG followed by a Control value between 1 and 2 5 Not possible to attenuate the signal up to 2 5 times assumes that cursors are not being used 5 The 9400A sets the VALUE ADAPTED bit if an out of range value is given The 9400A sets the ENVIRONMENT ERROR if the SELECTed trace is OFF VERT POSITION VP lt gt lt 16 00 DIV to 16 00 DIV gt VERT POSITION is applied to the SELECTed trace This command instructs the 9400A to modify the display position not the acquisition offset of the selected trace by up to 16 divisions relative to the original position at acquisition Remote Operations 7 17 6 7 The 9400A sets the VALUE ADAPTED bit if an out of range value is given The 9400A sets the ENVIRONMENT ERROR If the SELECTed t
154. he trigger character has been received The 9400A appends lt END gt to the SRQ string but not the lt TRAILER gt lt ESC gt Selects DTR CTS hardwire handshake protocol THIS COMMMAND IS IMMEDIATELY EXECUTED lt ESC gt Selects XON ASCII DC1 character XOFF ASCII DC3 character handshake protocol DEFAULT THIS COMMAND IS IMMEDIATELY EXECUTED lt ESC gt The 9400A does not echo characters received THIS COMMMAND IS IMMEDIATELY EXECUTED lt ESC gt The 9400A echoes characters received DEFAULT THIS COMMMAND IS IMMEDIATELY EXECUTED lt ESC gt lt When its output buffer is full the 9400A stops until more space is created in the output buffer i e until the host computer has read some characters THIS COMMMAND IS IMMEDIATELY EXECUTED Remote Operations 7 42 7 7 8 lt ESC gt gt If the output buffer becomes full the 9400A overwrites the last character DEFAULT THIS COMMMAND IS IMMEDIATELY EXECUTED 9 lt ESC gt R Sets the 9400A to REMOTE 10 lt ESC gt L Sets the 9400A to LOCAL 11 lt ESC gt C The 9400A executes a DEVICE CLEAR command clears the input and output buffers all the status bytes except STB 4 and all the corresponding masks It then terminates plotting and data transmission and resets the RS 232 C REMOTE port to DEFAULT setting THIS COMMMAND IS IMMEDIATELY EXECUTED 12 lt ESC gt T The 9400A executes a TRIGGER command see Section 7 6 9
155. ime point Indicates the time between digitized points for the corresponding time base setting Points div This parameter indicates the number of digitized points per division on any non expanded waveforms displayed Segments for SEQNCE This parameter indicates the number of segments selected for sequential acquisition On screen modification of this parameter is possible by pressing the Modify Segments button 4 to change the indicated segment number from 8 to 250 in a rolling sequence Set CHAN 1 Attenuator 6 and set CHAN 2 Attenuator 7 allow the user to enter probe attenuation factors of 10 100 and 1000 Press the Return key 10 to list the available menus For information concerning the other parameters displayed on the Panel Status menu see Section 5 1 Manual Operation 5 21 Memory Status The Panel Status menu displays acquisition parameters for waveforms to be acquired after receiving a trigger signal On the other hand the Memory Status menu displays all acquisition parameters for waveforms currently stored in the various memories of the 9400A The annotation used for Memory Status is similar to that of the Panel Status menu Pressing the Memory Status button 3 displays the Memory Status menu in Figure 5 11 Angara MEMORY STATUS V 2 08FT Ch 1 2 e STATUS Total V div 50 0 nV 50 0 nV Exp A B OF Feet Omv 0 ny rn Coupling BW Linit AC 1 MO OFF AC1MO OFF Mem C D Time Freq div 5 me 5 meo ST
156. ing W i 4 W i 3 8 W i 2 28 W i 1 56 W i 70 Cg i 256 256 256 256 256 W i 1 56 W i 2 28 W i 3 8 W i 4 T 256 256 256 256 WPO1 Waveform Processing Option 10 7 10 3 Remote Control of Waveform Processing Functions Remote control of the waveform processing is essentially achieved with extensions of existing commands No processing occurs if the corresponding TRACE FUNCTION E TRFE or TRACE FUNCTION F TRFF is OFF see Section 7 6 3 This is also true even if the SCREEN has been turned OFF Averaging can be stopped and continued by switching from TRIG MODE NORM to TRIG MODE SINGLE and vice versa Of course it can also be stopped by turning its corresponding trace OFF An average or an accumulation of extrema can be reset by a new command AVERAGE RESET A new function or new processing parameters are defined with extensions to the command REDEFINE In addition the command INSPECT allows some characteristics of the waveform to be known before it is read out 1 AVERAGE RESET ARST x The accumulated average or extrema of the SELECTed trace is reset This command can only be applied to FUNCTION E or to FUNCTION F The 9400A sets the ENVIRONMENT ERROR if the SELECTed trace if OFF if the SELECTed trace is neither FUNCTION E nor FUNCTION F The INSPECT commands of Section 7 6 5 have been extended to cover the inspection of FUNCTIONS E and F by including the following mnemonics 2 INSPEC
157. ing preceded by the WRITE command the block will be purged and syntax error 11 will be produced Invalid Header Note Block data must end with a legal Trailer such as lt CR gt lt LF gt or lt CRLF gt 6 INSPECT INS lt CHANNEL 1 LIMIT C1 LI gt lt CHANNEL 2 LIMIT C2 LI gt lt MEMORY C LIMIT MC LI gt lt MEMORY D LIMIT MD LI gt instructs the 9400A to return a character string containing the lower and upper address limits of the current waveform or INSPECT INS lt CHANNEL 1 NSWEEPS C1 NS gt lt CHANNEL 2 NSWEEPS C2 NS gt lt MEMORY C NSWEEPS MC NS gt lt MEMORY D NSWEEPS MD NS gt instructs the 9400A to return a character string containing the number of sweeps in averaging and extrema or INSPECT INS lt MEMORY C INTVAL MC IV gt lt MEMORY D INTVAL MD IV gt instructs the 9400A to return a character string containing the interval between data points used by a waveform processing function This value may be used as the lt intval gt parameter in the readout of such waveforms if the user wishes to read only the computed data points and none of the interpolated points Remote Operations 7 29 7 6 6 Other Remote Commands 1 CALIBRATE CAL 2 3 forces the 9400A to do a calibration of the interpolator and of both input channels at the current gain and bandwidth settings or CALIBRATE CAL NP NP N lt 7 lt ON l
158. isions from the center of the screen and is manually adjustable or programmable in 0 04 division increments A pair of upward or downward pointing double shaft arrows indicates when the trace has been positioned outside the grid as shown in Figure 5 3 Moin Menu UPWARD and DOWNWARD POINTING DOUBLE SHAFT ARROWS INDICATING THAT CHANNEL 1 and 2 ARE OFF SCREEN Figure 5 3 PROBES Two Model P9010 passive probes are supplied with the 9400A These probes have 10 MQ input impedance and 6 pF capacitance The system bandwidth with P9010 probes is DC to 100 MHz in 1 MQ DC coupling and lt 10 Hz to 100 MHz in AC coupling Active FET probes Tektronix models P6201 P6202a and P6230 may be powered via probe power connectors on the rear panel Manual Operation 5 3 5 1 2 PROBE CALIBRATION 19 20 To calibrate the P9010 Probe connect it to the CHAN 1 or CHAN 2 BNC connector 21 Connect the probe s grounding alligator clip to the front panel ground lug 20 of the oscilloscope and the tip to lug 19 Adjust the 9400A s front panel controls as described in Section 8 1 In case of over or undershooting of the displayed signal it is possible to adjust the P9010 Probe by inserting the small screwdriver supplied with the probe package into the trimmer on the probe s barrel and turning it clockwise or counter clockwise to achieve an optimal square wave contour BANDWIDTH LIMIT 50 By setting the BANDWIDTH LIMIT button to
159. its 7 0 7 0 7 0 6 2 5 0 x including the front end amplifier sample and hold and ADC 9400A PERFORMANCE Table 2 1 Product Description 2 2 2 4 2 5 2 6 2 7 Trigger The 9400A s digitally controlled trigger system offers facilities such as pre trigger recording bi slope and window triggering sequence and roll modes in addition to the standard operating modes of Auto Normal and Single Hold The trigger source can be external or can be either of the two inputs and the coupling is selected from AC LF REJect HF REJect and DC Automatic Calibration The 9400A has an automatic calibration facility that ensures overall vertical accuracies of 2 optionally 1 and 20 psec RMS for the unit s crystal controlled time base The time base is calibrated each time the 9400A s time base control is adjusted to a new TIME DIV setting vertical gain and offset calibration take place each time the front panel fixed gain control for either CHAN 1 or CHAN 2 is adjusted to a new VOLTS DIV setting Calibration of both channels also takes place each time the BANDWIDTH LIMIT push button is pressed Further information on automatic calibration may be found in Section 9 4 Auto calibration Display The 9400A s large 12 5 cm x 17 5 cm 5 x 7 inches screen displays analog waveforms with high precision and serves as an interactive user friendly interface via a set of screen oriented push buttons located immediately to the l
160. l trigger or ground in external trigger with the TRIGGER LEVEL control 33 Using the same basic acquisition parameters and signal used in Section 8 5 it is possible to halt the rolling signal by increasing its amplitude until it crosses the positive or negative window which defines the trigger conditions Procedure 1 Set the TRIGGER SLOPE push button 25 to POS NEG Both the POS and NEG LEDs will light up when push button 25 has been pressed the correct number of times 2 Set the COUPLING MODE push button 30 to the AUTO Trigger Mode 3 Adjust the CHAN 2 OFFSET control 32 in order to center the sine wave display at mid screen 4 Select a trigger window just beyond the positive or negative half cycle of the currently displayed sine wave by adjusting the TRIGGER LEVEL control 33 to approximately 3 0 divisions Note that when Window Triggering has been selected via push button 25 a corresponding message is displayed below the bottom graticule line on the right hand portion of the screen in the abridged Panel Status field This field enables you to adjust the positive negative trigger window desired without having to call the Panel Status menu 5 Gradually increase the amplitude of the output signal from your signal generator until the positive and negative half cycle of the displayed sine wave exceeds 3 0 divisions with reference to the zero base line Resulting Display Rolling will cease when the rolling
161. l WPO1 functions Averaging Extrema Arithmetic Functions and Smoothing can be applied to waveforms either before or after the FFT processing Menus and front panel controls related to FFT are similar to the corresponding WPO1 controls see Section 10 1 Remote control commands related to FFT provide for the definition of processing and the readout of waveform data and status as well as the loading of reference waveforms into the 9400A s memories C D The commands are similar to the corresponding WPO1 commands see Sections 7 10 3 and 11 3 Spectra are computed over the full length of the source time domain waveform Sub sampling of the source waveform is available with the Transform Size option in the FFT menu so that the the computation speed can be traded against the frequency range Spectra are displayed with frequency axes running from zero to Nyquist frequency over 5 or 6 25 divisions with the frequency scale factor in a 1 2 5 sequence The Time Magnifier operates on the FFT output traces as a Frequency Magnifier up to 100 times Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 2 11 2 The Display Control knobs provide vertical expansion up to 10 times and vertical position control To read the amplitude and frequency of the data point the Marker can be moved over into the frequency domain by going beyond the right hand edge of the time domain waveform The Time Cursors
162. ll the other functions can FUNCTION E can only be a source for waveform FUNCTION F WPO1 Waveform Processing Option 10 10 lt maxswps gt lt 10 gt Maximum number of sweeps lt 20 gt lt 50 gt Default 1000 lt 100 gt lt 500000 gt lt 1000000 gt Any number outside the 1 2 5 progression generates a semantic error lt reject gt lt ON gt Overflow rejection lt OFF gt Default OFF lt dither gt O to 6 Dithering range O no dithering Default 0 Any other number generates a semantic error 1 3 7 15 31 63 127 lt weight gt Continuous averaging weight RA N N N N N Default 7 N N NP N VN VV Any other number generates a semantic error lt e type gt lt ROOF gt Extrema type lt FLOOR gt Default ROOF lt a type gt lt SUM gt Arithmetic type lt DIFFERENCE DIF gt lt PRODUCT PRD gt Default SUM lt RATIO RIO gt lt f type gt lt DIFFERENTIATE DIFF gt Function type lt INTEGRAL INTEG gt lt NEGATION NEGAT gt Default NEGATION lt SQUAREROOT SQRT gt lt SQUARE SQR gt WPO1 Waveform Processing Option 10 11 lt s type gt Smoothing type lt 1 lt 3 lt 5 Default 3 pt smoothing lt 7 lt 9 V NP NP VV Any other number generates a semantic error lt m fact gt 0 01 to 9 99 Multiplication factor Default 1 00 Any value smaller than 0 01 or greater than 9 99 is adapted to the nearest legal v
163. lly with the dithering offset Their waveform descriptors take the additional offset into account so that waveforms as read out by remote control and cursor measurements are always correct Offset dithering is of interest when the waveform to be averaged is already relatively clean i e contains noise variations of the order of 1 5 of a division or less In this case dithering makes the sequentially acquired waveforms use slightly different portions of the ADC Thus the differential non linearities that any flash ADC has are averaged out It can be expected that the differential non linearities are reduced by up to a factor of 4 when using 6 LSB dithering Waveforms which have high levels of noise gt 1 5 of a vertical division do their own dithering making artificial offset variations unnecessary Continuous Average Continuous averaging sometimes called exponential averaging consists of the repeated addition with UNEQUAL weight of recurrences of the source waveform Each newly acquired waveform is added to he accumulated average according to the formula N 1 1 S i new S i old re N N Where i Index over all data points of the waveforms W i Newly acquired waveform S i old old accumulated average S i new new accumulated average N May be 2 4 8 16 32 64 or 128 The coefficients N 1 N and 1 N are the weighting factors which determine the speed at which the continuous average follows any m
164. ly recharged during operation The battery pack can be accessed by pressing the plastic latch at the top of the cover and pulling it downward and toward the user GPIB and RS 232 C Port Selection 54 The 9400A s rear panel thumbwheel switch is used to set addresses for programmed or remote oscilloscope operation Any one of addresses 31 99 selects the RS 232 C port Addresses 0 30 define the 9400A s_ address when using the optional GPIB IEEE 488 port GPIB and RS 232 C pin assignments are clearly indicated on the rear panel next to each connector Rear Panel Controls and Connectors 6 1 Plotter Connector 5 7 In addition to the RS 232 C port 56 used for remote 9400A operation a second RS 232 C port 57 has been incorporated to facilitate direct interfacing of the 9400A with a digital plotter Plotters are used for hard copy archiving of displayed waveforms and other screen data Pin assignments for the plotter connector are identical to those of the remote RS 232 C port 56 While a plotter unit connected to the 9400A s RS 232 C port can be computer controlled from a host computer via the optional GPIB port the oscilloscope s on board digital plotter drivers permit hard copies to be made without an external computer Plotter connector pin assignments Pin Description 2 TxD Transmitted Data from the 9400A 3 RxD Received Data to the 9400A 4 RTS Request To Send always on from the 9400A 5 CTS Clear To Se
165. m functions integration differentiation square square root negation inversion Smoothing 1 3 5 7 9 point filters Extrema records extreme values envelopes over a programmable number of sweeps CHAINING OF OPERATIONS Two functions can be automatically chained using functions E and F Examples fnE CH1 CH2 fnF FFT of fnE fnE FFT of CH1 fnF Integral fnE Manual chaining using memories C and D for intermediate results may continue indefinitely 1 1 1 2 SECTION 1 GENERAL INFORMATION Warranty LeCroy warrants its oscilloscope products to operate within specifications under normal use and services them for a period of two years from the date of shipment Spares replacement parts and repairs are warranted for 90 days Software is thoroughly tested but is supplied as is with no warranty of any kind covering detailed performance Accessory products not manufactured by LeCroy are covered solely by the warranty of the original equipment manufacturer In exercising this warranty LeCroy will repair or at its option replace any product returned to the Customer Service Department or an authorized service facility within the warranty period provided that the warrantor s examination discloses that the product is defective due to workmanship or materials and that the defect has not been caused by misuse neglect accident or abnormal conditions or operation The purchaser is responsible for the tran
166. mance digital oscilloscope suited to research and to test and measurement applications It is used to capture analyze display and archive electrical waveforms in fields such as electronic engineering physics research automated testing and measurement telecommunications electromagnetic pulse and interference measurement LIDAR technology and ultrasonics research 9400A Architecture The 9400A has been built around the powerful 68000 microprocessor which is used by the unit to perform computations and control oscilloscope operation Attenuator Amplitier Sampie aDC Acquisition Processor hold memory interfaces CH1 s RS232C lt By ae Ked BS L AC Offset Gain RS 232C gn Control K Part l ad IEEE 468 Offset Gain H CH2 son i ae DATA STORAGE OPE FRAT A Pt fo faci tae firme e enon a cc K bytes AC Up S ars Front Panel 9400A BLOCK DIAGRAM Figure 2 1 Product Description 2 3 All front panel rotary knobs and push buttons are constantly monitored by the internal processor and front panel setups are rapidly reconfigured via the unit s internal 16 bit bus Data are quickly processed according to the selected front panel setups and are transferred to the acquisition memory for direct waveform display or stored in the 9400A s reference memories The 68000 controls the unit s two RS 232 C ports which are used to directly interface the 9400A to a digital plotter remote terminal or other slow speed devi
167. mber of sweeps 10 to 1 000 000 can be selected ina 1 2 5 sequence Number of points averaged over CH1 CH2 50 to 32000 in 10 steps Offset dithering up to 6 LSBs may be chosen Artifact Rejection ON OFF Theoretical signal to noise improvement achievable 57 dB Vertical expansion 10 times maximum Maximum sensitivity 500 uV div after vertical expansion CONTINUOUS AVERAGING Number of sweeps infinite Weighting factors selectable 1 1 1 3 1 7 1 15 1 31 1 127 Number of points averaged 50 to 32000 in 10 steps Vertical expansion 10 times maximum Maximum sensitivity 500 yV div after vertical expansion AVERAGING SPEED The figures below assume that the display time between triggers is negligible record length summation of points sweeps sec 32000 3 25000 4 12500 6 6250 13 2500 32 1250 51 625 73 250 100 125 112 50 118 rr Mean value smoothing divides the acquired signal into a chosen number of segments and then gener ates the smoothed waveform in which each displayed point corresponds to the mean value of n points contained in the corresponding segment The number of segments can be between 50 and 32000 Mean value smoothing takes all digitized points on the screen into account N point smoothing applies a moving average of N points symmetrically placed around each of the 50 to 32000 selected points for display Each selected point Yk is replaced in the smoothed waveform by
168. memories E and F optional Two 32K 16 bit word memories 64K total for waveform processing Glitch detection Permanent glitch detection for events down to 0 04 of the time base setting 10 nsec minimum HORIZONTAL SECTION Time Base Range 2 nsec div to 100 sec div Accuracy Better than 0 002 of the time base setting Interpolator resolution 10 psec Acquisition Modes Random Interleaved Sampling RIS for repetitive signals from 2 nsec div to 2 usec div Single shot for transient signals and repetitive signals from 50 nsec div to 200 msec div Roll for slowly changing signals from 500 msec div to 100 sec div Sequence for capturing transients in segmented memories of 8 15 31 62 125 or 250 blocks Trigger Sources CHANT CHAN2 LINE EXT EXT 10 Slope Positive negative window Coupling AC LE REJ HF REJ DC Modes Sequence stores multiple events in segmented acquisi tion memories Auto automatically re arms after each sweep If no trig ger occurs one is generated at 2 Hz repetition rate Normal re arms after each sweep If no trigger occurs after 2 sec the display is erased Single hold holds display after a trigger occurs Re arms only when the single button is pressed again Pre trigger Adjustable in 0 2 increments to 100 Post trigger delay Adjustable in 0 02 division increments up to 10 000 divisions External trigger input 1MQ lt 30pF 250V max
169. mories following acquisition of each waveform The Auto store mode is particularly useful whenever the user wishes to acquire single events in the Normal trigger mode appearing at intervals gt 2 sec As explained in Section 5 2 5 in the Normal trigger mode the trigger circuit automatically re arms after 2 sec causing the currently stored waveform to be erased from memory pressing the Modify Auto store push button 2 once causes the waveform currently contained in the 9400A s CHAN 1 acquisition memory to be stored automatically into Memory C Continue pressing the Modify Auto store push button 2 to see all the possibilities CHAN 1 into Memory C CHAN 1 into Memory D CHAN 2 into Memory C CHAN 2 into Memory D CHAN 1 into Memory C and CHAN 2 into Memory D Auto store in Memory C Procedure 1 Using the same signal as in measurement example 8 2 set TRIGGER MODE push button 29 to NORM rather than SINGLE HOLD 2 With the Main Menu displayed on the CRT press the Special Modes push button 7 3 Press Modify Auto store push button 2 once in order to cause the signal input to CHAN 1 to be automatically stored into Memory C with each new trigger cycle 4 Return to the Main Menu by pressing Return push button 10 5 Call Memory C by pressing MEMORY C push button 47 6 Trigger the signal source Basic 9400A Waveform Measurements and Operating Procedures 8 12 8 11 Note that Memory C contai
170. n the case of products returned to the factory a Return Authorization Number RAN The RAN may be obtained by contacting the Customer Services Department in New York on 914 578 6059 in Geneva on 022 782 33 55 or your nearest sales office Return shipments should be made prepaid LeCroy will not accept C 0 D or Collect Return Shipments Air freight is generally recommended Wherever possible the original shipping carton should be used Ifa substitute carton is used it should be rigid and should be packed such that the product is surrounded with a minimum of four inches of excelsior or a Similar shock absorbing material In addressing the shipment it is important that the Return Authorization Number be displayed on the outside of the container to ensure its prompt routing to the proper department within LeCroy General Information 1 2 1 6 Initial Inspection It is recommended that the shipment be thoroughly inspected immediately upon delivery to the purchaser All material in the container should be checked against the enclosed Packing List LeCroy cannot accept responsibility for shortages in comparison with the Packing List unless notified promptly If the shipment is damaged in any way please contact the factory or local field office immediately General Information 1 3 2 1 2 2 AC EXTERNAL mta IST af gt Herh Bufter GPIB SECTION 2 PRODUCT DESCRIPTION Introduction The LeCroy 9400A is a high perfor
171. n completed Whenever a bit of this status byte gets set and the corresponding bit in MASK5 is also set the OPERATION COMPLETE bit DIO 5 in STB1 is set Remote Operations 7 36 Bits 0 2 3 Set when a screen dump in REMOTE only is finished Set when calibration is done in REMOTE only Average END ERROR Status Byte STB 6 This status byte contains the coded value of the most recently detected error The individual bits have no well defined meaning Whenever MASK 6 is non zero and the code in STB 6 is set to a non zero value the ERROR bit DIO 6 in STB1 is set Code Syntax errors 30 40 50 60 100 1 STB No error Not all 9400A responses have been read upon receipt of a new command string terminated with lt END gt Output buffer has been flushed Invalid separator or too many parameters Invalid header Invalid number format Invalid keyword Invalid block 2 or more strings in the same command Command permission error REMOTE only command has been received while the 9400A is in LOCAL or SCREEN control command has been received while SCREEN control is LOCAL The 9400A has received a command for an option that is not installed Semantic error false number of parameters or false parameter in a command Environment error the 9400A is not set to the proper status to accept the received command trace OFF false format Descriptor error an inconsistency has been detected in the
172. nals up to 5 gigasamples sec for repetitive signals simul taneously on both channels Aperture uncertainty 10 psec Overall dynamic accuracy typical Sine wave applied to the BNC input for RMS curve fit at 80 full scale The accu racy measurement includes the front end amplifier sample amp hold and ADC Input frequency Nyquist MHz 1 0 10 0 50 0 100 0 175 0 Signal to noise 1 4 37 1 29 9 Effective bits 7 0 7 0 7 0 6 2 5 0 Acquisition memories Channels 1 and 2 Two 32K 8 bit word memories 64K total which can be segmented into 8 15 31 62 125 or 250 blocks Reference memories C and D Two 32K 16 bit word me mories 64K total which can store two acquired and or processed waveforms Function memories E and F optional Two 32K 16 bit word memories 64K total for waveform processing Glitch detection Permanent glitch detection for events down to 0 04 of the time base setting 10 nsec minimum HORIZONTAL SECTION Time Base Range 2 nsec div to 100 sec div Accuracy Better than 0 002 of the time base setting interpolator resolution 10 psec Acquisition Modes Random Interleaved Sampling RIS for repetitive signals from 2 nsec div to 2 usec div Single shot for transient signals and repetitive signals from 50 nsec div to 200 msec div Roll for slowly changing signals from 500 msec div to 100 sec div Sequence for capturing transients in segmented memories of 8 15 31
173. nction E Number of sweeps is 20 11 4 2 Additional Values in the Descriptors of FFT Processed Waveforms The oscilloscope waveform and descriptors can be read into a host computer see Section 7 6 5 With the WPO2 option the Waveform Descriptor length is unchanged 150 bytes However in addition to the Descriptor field values defined in Section 7 7 and 10 4 the following fields have new or additional values pertaining to the results of FFT processing Fast Fourier Waveform Processing Option WPO2 V 2 06FT 11 9 Pos Size Meaning 9 8 bit Time base sec div 4 36 see Section 7 7 Frequency base Hz div 59 5 mHz 60 10 mHz 61 30 mHz 62 50 mHz 86 5 MHz 87 10 MHz 88 20 MHz 91 0 2 GHz 92 0 5 GHz Displayed Record Length 59 86 12500 points 87 10000 points 88 92 12500 points 10 8 bit Sampling interval sec point 11 45 see Section 7 7 Frequency interval Hz point 59 2 0 wHz 60 5 0 Hz 61 10 0 wHz 62 20 0 wuHz 91 0 1 MHz g 92 0 2 MHz 34 8 bit Data processing of this record 5 FFT 6 FFT AVERAGE 36 16 bit Units code for power of volts code 256 power 38 16 bit Units code for power of seconds Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 10 11 5 11 5 1 code 256 power 40 16 bit Units code for power of arbitrary unit code 256 power 42 8 bit Units identity of arbitrary unit undefined dB degrees amp KA
174. nd to the 9400A When TRUE the 9400A can transmit When FALSE transmission stops Used for 9400A output hardware handshake 20 DTR Data Terminal Ready from the 9400A Always TRUE 6 DSR Data Set Ready to the 9400A 1 GND Protective Ground 7 SIG GND Signal Ground This corresponds to a DTE Data Terminal Equipment configuration Rear Panel Controls and Connectors 6 2 7 1 7 2 SECTION 7 REMOTE OPERATIONS Programmed Control Most of the front panel and internal functions of the 9400A can be remotely controlled using a set of high level English like commands and mnemonics For example a command followed by lt gt tells the scope to transfer to the host computer the value of the control setting defined by the command It is thus possible to read the complete status of the instrument by repeated queries It is also possible to save the entire status of the instrument in binary format with a single command The 9400A s remote control facility allows complex measurement procedures and instrument setups a particularly useful feature in experimental and automated testing environments The 9400A can be programmed via the rear panel RS 232 C port interfaced with a computer terminal or a computer Remote control is also possible via GPIB IEEE 488 bus if the 9400A has been fitted with the option OPO02 In this case data transfer rates are relatively faster To help users who wish to remotely control the Models 9400 125 MHz ban
175. ns an exact copy of the most recent waveform stored in CHAN 1 The display of CHAN 1 waveform disappears about 2 seconds after a valid trigger is detected Common Expand Mode Sections 8 3 and 8 8 describe the expansion of displayed traces independently in order to provide a magnified version of a portion of the waveform currently in CHAN 1 CHAN 2 or those stored in reference Memories C or D However in certain applications it is convenient to be able to move the intensified region along two traces simultaneously Procedure 1 Using the same front panel setup and the 100 nsec signal described in Section 8 2 connect one of the outputs of your pulse generator to the CHAN 1 input connector 21 2 Connect a second output of your pulse generator to the CHAN 2 input connector 21 3 With the Main Menu displayed on the left hand side of the CRT press push button 7 to call the Special Modes menu 4 Press Modify Common Expand push button 4 to set the oscilloscope to the Common Expand mode 5 Return to the Main Menu by pressing Return 10 6 Press DUAL GRID 14 7 Press EXPAND A and EXPAND B 46 8 Press RESET 41 to synchronize the intensified sections along the CHAN 1 and 2 trace Note that at this point two sets of overlapping traces will be displayed on the screen Separate CHAN 1 and CHAN 2 by adjusting the CHAN 1 or 2 OFFSET controls 32 Separate expanded traces A and B by first selecting the X CHAN 1 pus
176. nstruments Inc All rights reserved In the following description the commands which must be sent are in upper case letters Answers or comments are in lower case Each command must be followed by lt CR gt Basic 9400A Waveform Measurements and Operating Procedures 8 18 8 14 4 Enter IBFIND GPIB in upper or lower case at which point the following program will be executed Meaning IBSIC PC acts as controller Status Message Returned IBTMO 12 3 sec time out Status Message Returned IBEOT 1 PC automatically enables lt EOI gt line Status Message Returned on final character of message IBSRE 1 Enable Remote 9400A operation Status Message Returned IBCMD S PC Talker 9400A Listener Status Message Returned 9400A enters REMOTE IBWRT TD 1MS TD TIME DIV set to 1 msec read Status Message Returned current value IBCMD D PC Listener 9400A Talker Status Message Returned IBRD 120 PC to read lt 120 characters and Status Message Returned stop when it encounters lt EQI gt kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk At this point the following message will be displayed with corresponding Hexadecimal ASCII codes to the left 54 44 20 31 2E 30 30 45 TD 1 008 2D 30 33 20 53 OD OA 03 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk IBONL Disconnect PC from GPIB set Status Message Returned 9400A to Local operation E Exit IBIC program Making a Plot when the Compu
177. nt panel setups including WPO1 and WP02 menu settings can be stored and recalled by the menu buttons at the left side of the 9400A screen WP02 FFT INSTALLATION A WPO02 FFT package may be retrofitted to a LeCroy 9400A Digital Oscilloscope The WPO Signal Processing hardware and software is a prerequisite for installation of WPO2 T divSOms Ch2 gt 50 mY 8 Trig 12div CHAN 2 Long records give wide frequency span FFT of 1000 Hz sine amplitude modulated square wave recorded over 25 000 points shows harmonics up to 25 kHz Expansion shows sidebands at 10 Hz and 30 1 dB ORDERING INFORMATION Oscilloscope and Options Code Description 9400A Digital Oscilloscope 9400A0OP01 High precision option 1 DC accuracy 9400AWPO1 Waveform processing option 9400AWPO2 Fast Fourier processing option requires 9400AWP01 9400AMS01 Mass storage and remote contro package including an IBM lap top controller interface cables and software 9400AIM01 GPIB interface for IBM PCC computers Oscilloscope Accessories OM9400A Operator s Manual SM9400A Service Manual CA9001 Camera using Polaroid film and Hood CA9002 Camera adapter 35 mm with Hood CS9400 Certified Calibration DP9001 Digital Plotter 8 pen A4 size OC9001 Oscilloscope Cart RM9400 Adapter Kit for Rack Mounting SG9001 High voltage protector TC9001 Transit Case TC9002 Protective Cover ns FREQUENCY Frequency range DC to gt 175 MHz Frequency
178. ntrol horizontally expands waveforms up to 100 times Overall timing accuracy is improved at higher magnification factors since the expand function is controlled digitally and makes use of the scope s high number of recorded data points This control has no effect on MEMORY C D or FUNCTION E F SELECT button 44 Chooses one of the traces EXPAND A through FUNCTION F to be controlled via Display Control knobs and buttons 39 45 The selected trace is indicated by a rectangular frame around the waveform descriptor in the Displayed Trace field V Pressing the SELECT button 44 moves the rectangle to the next displayed trace in a rolling sequence REDEFINE button 45 Used to redefine the identity of the selected waveform EXPAND A B traces may be redefined to be the expansion of CHAN 1 or CHAN 2 MEMORY C or D or FUNCTION E or F for 9400A s equipped with the Waveform Processing Option Pressing the REDEFINE button 45 calls a menu on the left hand side of the screen enabling selection of the desired source redefinition When the button corresponding to this redefinition is pressed EXPAND A or B will be temporarily selected as the new source trace until subsequent redefinition is performed The default signal sources are CHAN 1 for EXPAND A and CHAN 2 for EXPAND B It is not possible to redefine Memories C and D Function E and F may only be redefined if your 9400A is equipped with the Waveform Processing Option For s
179. o be read for example 1 read all points 4 leave out 3 of 4 data values lt values gt O to 32000 Number of data values to read 32000 to 32000 Address of first data point relative to the left hand side of the screen lt addr gt lt sweep gt 0 to 250 Sweep number in SEQNCE waveforms numbered from 1 to max sweeps O read all sweeps Remote Operations 7 24 The parameter list is optional Any omitted parameter is set toa default value lt intval gt 1 i e leave no values out lt values gt values on the screen lt addr gt address of left most value on the screen lt sweep gt 0 i e read all sweeps Thus the omission of all parameters results in all the data values on the screen being read A detailed explanation of the data addressing conventions is given in Section 7 9 If the user does not specify the number of data values READ DATA transfers are executed over the number of data values displayed on screen 1 i e if the screen shows nominally 25000 data values 25001 values are transferred Data formats The descriptor DESC the data DATA and the time s TIME are each transmitted as a single block unless a maximum block size has been specified with the command COMM BLOCKSIZE When all data are read they are transmitted as three blocks in the order descriptor data time s When all sweeps of a SEQNCE data record are read sweep
180. odification of the source waveform Note that they add up to the value of 1 so that the continuous average of noisy but otherwise unmodified waveforms resembles the summed average of such waveforms WPO1 Waveform Processing Option 10 4 10 2 3 However the statistical significance of a continuous average is less good since the last acquired waveform has more weight than all previously acquired ones Thus the continuous average is dominated by the statistical fluctuations of the most recently acquired waveforms The continuous average never stops at a maximum number of sweeps The weight of old waveforms gradually tends to zero but they are theoretically never completely forgotten The averaging process may be interrupted by switching the trigger mode from NORM to SINGLE 29 or by turning the function trace OFF 48 Averaging will continue when these actions are reversed The currently accumulated average may be reset by either changing an acquisition parameter such as input gain offset or coupling trigger condition or the time base or by pressing the RESET push button 41 twice in quick succession remember that FUNCTION E or F must be selected Continuous averaging may be performed over CHANNEL 1 or 2 FUNCTION F may also average over FUNCTION E therefore allowing averaging over functions Extrema The computation of extrema consists of a repeated comparison of recurrences of the source waveform with the alrea
181. of the 9400A Digital Oscilloscope capture waveforms with high fidelity At similar time base settings the 9400A s long memories allow sampling rates up to 25 times faster than that of instruments which have only 1K of acquisition memory see graph below Faster sampling rates ensure higher single shot bandwidth as well as significantly reducing problems caused by undersampling and aliasing The 9400A s long memo ries allow displayed waveforms to be expanded up to 100 times to show the finest signal details gt LJ LU 2 g LU ce Ln n D G gt zZz N x Transient recording With a sampling rate of 100 megasamples sec the 9400A is an extremely powerful transient recorder Long 32K data point acquisition memories combined with a continuously adjustable trigger from 100 pre trigger to 10 000 divisions post trigger at any time base setting ensure that rare events cannot be missed Both channels are sampled simultaneously so that exact time correlation is main tained between channels Full programmability All the 9400A s front panel controls are fully programmable via the two RS 232 C interface ports or the GPIB port A single push button initiates a screen dump for accurate color hard copies of the display via a wide range of digital plotters The GPIB comes complete with LeCroy MASP software offering computer conto and mass storage on any PC compatible with the IBM
182. of the signal energy of each peak into the neighboring frequency bins Redefine the Window Type to von Hann also called Hanning The skirts are reduced considerably the leakage is diminished Redefine the Transform size to 2500 You will obtain N 2500 and the Nyquist frequency of 125 kHz while the interval between the points bins will remain unchanged at 1 0 01 sec 100 Hz Define Function F as the FFT Power Average of Function E Using the Normal or Auto trigger mode you can average up to 200 Spectra and see the intermediate or final average on a linear scale Magnitude or dBm scale Power Spectrum or Power Density Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 4 11 4 1 16 Experiment Try other time base settings display modes numbers of points window types and signals to become familiar with the system Try combinations of FFT and the WPO1 processing functions You can define both Functions E and F as FFT of the same source waveform but with different parameters and compare the resulting traces Remote Control of FFT Processing Consult Sections 7 and 10 3 10 4 for general information on remote control using either the GPIB or the RS 232 C interface The additional forms of commands specific to the FFT option and the related fields of the Waveform Descriptor are described below Remote Commands The Redefine command has been extended to accept the parameters related to F
183. ol 33 is turned counter clockwise for bi slope triggering at base line level Turning the Trigger LEVEL control 33 clockwise generates a variable amplitude trigger window which is symmetrical with respect to the center of the screen internal trigger source and to ground external trigger source When uSing an internal trigger source the user may produce an asymmetrical window by offsetting the base line with respect to ground via Vertical OFFSET control 32 In the window triggering mode no trigger will occur while the Signal remains within the window A signal which exceeds the pre selected limits will generate a trigger and the signal is stored into the memory as shown in the following figure Chi 4 Y Menu OFF T div 2 e Ch2 Sony A Trigt 2 50 div Z CHAN 1 WINDOW TRIGGERING Figure 5 4 In the above figure the trigger level is 3 divisions as indicated in the Abridged Panel Status field Manual Operation 5 8 Trigger MODE 29 Selects the mode of trigger operation as follows SINGLE HOLD Selected using the lower button 29 In this mode the 9400A digitizes until a valid trigger is received After the waveform has been acquired and displayed no further signals can be acquired until the SINGLE HOLD button has been pressed again to re arm the trigger circuit in preparation for the next trigger signal This type of acquisition provides a simple means of recording a wide variety of transient events When the 940
184. onfiguration Although descriptions vary slightly pin assignments for the dedicated plotter interface Section 6 6 are identical to those for the remote RS 232 C connector above GPIB Port Option OPO2 only 55 The 9400A s GPIB interface optional complies with JIEEE 488 1978 standards and is intended to provide high speed data transfer in either the ASCII or binary format between the 9400A and the computer to which it is interfaced The maximum data transfer rate depending on the controller used may be as high as 400 kilobytes sec GPIB Port Selection 54 As mentioned in Section 6 5 the 9400A s_ rear panel thumbwheel switch is used to set addresses for programmed or remote oscilloscope operation Addresses 0 30 define the 9400A s address when using the GPIB IEEE 488 port using any one of addresses 31 99 selects the RS 232 C port The thumbwheel is read at power ON only Whenever the GPIB address is changed the power must be turned off and on again GPIB functions are clearly indicated on the rear panel next to the GPIB connector Remote Operations 7 2 7 4 7 4 1 GPIB Functions The following is a list of the various functions provided via the 9400A s rear panel GPIB connector AH1 Complete Acceptor Handshake SH1 Complete Source Handshake L4 Partial Listener Function T5 Complete Talker Function SR1 Complete Service Request Function RL2 Partial Remote Local Function DC1 Complete Device Clear
185. ontrol of all of the scope s functions by means of a computer terminal For a complete listing of the various commands used to program the 9400A see Section 7 6 The following examples are given to present the 9400A s remote control from a computer To disable the character echoing from the 9400A issue the following command lt ESC gt l Preliminary Hardware Setup 1 Set the thumbwheel switch 54 on the rear panel of the 9400A to a value greater than 31 2 Power up the 9400A 3 Connect a computer through an RS 232 C cable to the Remote port connector 56 on the rear panel of the 9400A 4 Call the RS 232 C menu by pressing push button 8 Then match the data transfer speed and character formats of the computer and oscilloscope See Section 5 2 6 Basic 9400A Waveform Measurements and Operating Procedures 8 14 I Remote Operation in the Interrogation Mode Programming Example Terminal Display of Current Time Base Setting Programming Procedure 1 Using any combination of upper or lower case characters enter the letters TD on your keyboard followed by a space comma or by the equal sign followed by a question mark followed by lt CR gt as follows TD lt CR gt Resulting Display Immediately upon execution of the above sequence you will see the 9400A s current time base setting displayed on your terminal e g TIME DIV 100 S II Remote Operation in the Control Mode To modify the currentl
186. opic 10 2 4 Arithmetic options 10 3 1 AVERAGE RESET ARST 10 2 2 Averaging continuous 10 2 1 Averaging summed 10 2 3 Extrema 10 1 Function E 10 3 2 INSPECT INS 10 2 5 Mathematical functions 10 3 3 REDEFINE RDF 10 3 Remote control of waveform processing functions 10 2 Setting up a waveform processing function manually 10 2 6 Smoothing N point 10 5 Vertical scaling units 10 4 Waveform descriptor syntax 10 1 WPO1 waveform processing capabilities WPO1 Waveform Processing Option 10 17 11 1 SECTION 11 FAST FOURIER WAVEFORM PROCESSING OPTION WPO2 V 2 06FT Processing Capabilities The FFT option WPO2 adds a spectrum analysis capability to a 9400A already equipped with the waveform processing option WPO1 The 9400A s Functions E and F can be defined as the fast Fourier transform of one of the source waveforms Channel 1 Channel 2 Memory C Memory D and Function E for Function F only A glossary of the terms used in this chapter is given in Section 11 6 Values of the following FFT processing parameters can be selected in the FFT redefine menu or with remote control commands er ee pint et ee es ee ee ee ee mapa ee ee ee WW ee ee ee es re P ee apn ee ee n m ee ee ee es ee ee ee ee ee es ee PPE ee ee ee ee ee es ee ee ee es ee ee ee ee ee ee ee ee S ds mi i ii a m a P a m ee eee ee ie ei ee P cee ee ee ee ee ee k b ee hez i ee ba ee P T ee PP ee Pk ee se ee ee ee ee P ee TT ee ee ee oe oe Function
187. or i e 0 04 V div 0 div 25 7 div 50 6 div ouesse 200 O div 225 1 div 250 d dW O OOO OSG 400 8 div See Section 7 10 1 for an example of how data values are converted to volts in processed data records Input channel coupling at acquisition 0 DC 50 Q 1 Ground 2 DC 1 MQ 3 Ground 4 AC 1 MQ Attenuation of external probe must have been set up manually or by remote control O 1 1 10 2 100 3 1000 This value is already absorbed into the fixed vertical gain position 0 it serves only as a reminder here Bandwidth limit at acquisition O off 1 on Time base at acquisition coded as an integer 4 2 nsec div 5 5 nsec div 6 10 nsec div 7 20 nsec div E 34 20 sec div 35 50 sec div 36 100 sec div Remote Operations 7 44 Pos Size 10 8 bit 11 8 bit 12 8 bit 13 8 bit 14 8 bit 15 8 bit 16 16 bit Meaning Sampling interval at acquisition coded as an integer In interleaved sampling 12 4 nsec 11 2 nsec 13 8 nsec In non interleaved sampling 16 10 nsec 18 40 nsec 20 200 nsec 35 20 msec 17 0 nsec 19 80 nsec 21 400 nsec 34 8 msec 36 40 msec In addition to the intervals of the non interleaved sampling SEQNCE mode also uses 40 100 nsec 41 1 usec 42 10 usec 43 100 usec 44 1 msec 45 10 msec Record type O non interleaved 3 interleaved with 25 sweeps at 8 nsec interval 4 inte
188. ore user defined window functions may be loaded onto the 9400A via the GPIB interface Through multiplication they modify the acquired signal follow ed by FFT in an automated fashion MEMORIES Acquisition memory 32K x 8 bits per channel CH1 and CH2 Reference memory 32K x 16 bits per reference memory C and D Function memory 32K x 16 bits per function memory E and F The content of the acquisition and function memories can be stored in reference memories C and D Record length selection for FFT Function memories E and F only 50 25000 data points in 9 steps in 1 2 5 sequence Record lengths are selected by decimation after signal acquisition This implies that the Nyquist criterion can be adjusted and optimized after signal acquisition and prior to FFT execution Flattop d tk lt atiii atii TB Br 89T l E ee BU E IE H wd ln mine TH i E S z aM Se e l The sum of two 1 V p p sinusoids of 500 kHz and 527 5 kHz is digitized over 2 500 points and transformed to the frequency domain 4 different window functions are applied to indicate their effect on leakage suppression and spectral resolution The vertical scale factor is 10 dB div 80 dBm full scale REMOTE CONTROL All front panel controls and WP01 and WP02 processing functions are fully programmable via the 9400A GPIB and RS 232 C interfaces Simple English like mnemonics are used STORED FRONT PANELS Up to 7 fro
189. ored The only way to halt data acquisition is to select the SINGLE HOLD mode or switch the 9400A into AUTO mode and provide a trigger Manual Operation 5 9 AUTO Selected using button 29 This mode resembles the NORM mode except that it automatically generates an internal trigger and forces a waveform to appear on the screen whenever the selected trigger is not present for more than 500 msec When the 9400A auto triggers the display usually moves in time as the trigger is not time correlated with the input signal Auto trigger can not be used when the 9400A is in the RIS mode When the 9400A is in the Roll mode gt 500 msec div it samples input signals continuously In the AUTO mode any valid trigger will halt data acquisition once the trigger delay requirements have been satisfied SEQNCE Selected using the upper button 29 Sequence triggering enables the 9400A s acquisition memories to be partitioned into up to 250 segments Possible settings are 8 15 31 62 125 or 250 segments Waveform acquisition in SEQNCE mode is particularly useful in the case of short lived or echoed signals such as those typically encountered in RADAR SONAR LIDAR and NMR In this mode the time base setting determines the total duration TIME DIV x 10 of each segment Changing the number of required segments does not change the time base it only affects the number of digitized points record length per segment The number of
190. ors up to 128 Averages up to 100 000 words sec in summation mode l Offset Dithering Improves the vertical resolution for low noise measurements by several bits in summation averaging mode Reduces the effect of ADC differential non linearities Artifact Rejection Rejects waveforms that exceed the dynamic range of the ADC to ensure statistica validity of summed average results Extrema Mode Keeps track of time and ampli tude drift by storing extreme positive and negative values such as glitches over a programmable number of sweeps Powerful Arithmetic Processes addition subtrac tion multiplication or division on pairs of wave forms stored in the 9400A s memory locations CH1 CH2 C D and E Waveform data can be nor malized by additive or multiplicative constants FUNCTIONAL DESCRIPTION WP01 an optional waveform processing firmware package for the 9400A Digital Oscilloscope ts opti mized for processing signals in real time The powerful 68000 based system permits rapid represen tation of processed results such as averages differentiations multiplications integrations and smoothing of waveforms Waveform operations can be performed on live or stored signals or a combination of both They are selected through simple menus and it is even pos sible to chain them and compute for example the inte gral of the multiplication of two traces or average the difference of CH1 and CH2 WP01 include
191. ose tool for waveform recording and analysis Combining ease of use with a comprehensive range of measurement and processing capabilities it en ables extremely precise measurements The LeCroy 9400A provides 175 MHz bandwidth 100 megasamples sec 8 bit ADCs 2 DC accuracy 1 optional 32K memory per chan nel and up to 192K of waveform storage memory It is fully programmable over RS 232 C or GPIB interfaces Plotter drivers enable color archiving via a wide range of digital plotters Croy _ i pir 9400A FEATURES High bandwidth and precision Two independent channels each with 175 MHz bandwidth and a high performance 8 bit ADC handle input signals with better than 2 DC accuracy 1 optional The 9400A features sampling rates of 100 megasamples sec for transient events Long memories and a versatile cursor system inciuding voltage time and cross hair cursors give time measurements with an accuracy of 0 02 of the time base setting and reso lution of 0 002 full scale High resolution display The 9400A s large display screen produces bright stable razor sharp pictures of your signal under any repetition rate conditions Very accurate signal comparisons are possible as up to four waveforms live expanded or processed can be dis played simultaneously on the high resolution screen 1024 x 1024 pixels Long memories The long 32K acquisition memories
192. ote Operations 7 21 lt x gt O MM to 999 MM lt y gt O MM to 999 MM lt grid gt is the size length of a side of the standard square within the 8 times 10 squares grid lt x gt lt y gt are the positions of the lower left hand corner of the graticule with respect to the origin of the plotter The 9400A sets the VALUE ADAPTED bit if an out of range positive value is given Negative values generate a semantic error 3 SCREEN DUMP SD Instructs the 9400A to dump the screen display onto the plotter 4 TRANSMIT TX lt String to be transmitted to the plotter gt X Instructs the 9400A to transmit a character string to the plotter The string may be up to 43 characters in length and may include commands such as paper advance or print string This enables the user to add comments to a plot or generate multiple plots by remote control The 9400A sets the ENVIRONMENT ERROR if the 9400A is controlled through GPIB and if the plotter access port is the GPIB port 7 6 5 Transfer Commands 1 STORE STO 1 to7 k instructs the 9400A to store the current front panel configuration in one of 7 non volatile storage areas for later recall or STORE STO lt CHANNEL 1 C1 gt lt MEMORY C MC gt lt CHANNEL 2 C2 gt lt MEMORY D MD gt instructs the 9400A to store the waveform and the waveform descriptor of either Channel 1 or 2 into reference memories C or D
193. ource When the oscilloscope is set to LINE trigger source this command has no meaning and no error will be reported In the case of POS_ NEG triggering only a positive value is meaningful The 9400A sets the VALUE ADAPTED bit if an out of range value is given The 9400A sets the ENVIRONMENT ERROR if the DIV suffix is sent instead of V or if the V suffix is sent instead of DIV TRIG COUPLING TRC lt 7 gt lt AC gt X lt DC gt lt LF REJ LF gt lt HF REJ HF gt TRIG MODE TRM E gt 7 lt SEQNCE SE gt x lt AUTO AU gt lt NORM NO gt lt SINGLE SI gt The 9400A sets the ENVIRONMENT ERROR if SEQNCE is sent while the 9400A is in Taeecteaved Sampling TRIG SOURCE TRS c gt lt CHANNEL 1 C1 gt lt CHANNEL 2 C2 gt lt LINE LI gt lt EXT EX gt lt EXT 10 E 10 gt Remote Operations 7 13 8 TRIG SLOPE TRP lt 7 gt 7 lt POS PO gt lt NEG NE gt lt POS NEG PN gt x 9 SEGMENTS SEG lt gt lt 8 gt lt 15 gt x lt 31 gt lt 62 gt lt 125 gt lt 250 gt Indicates or selects the number of segments for waveforms acquired in SEQNCE mode 10 CHANNEL 1 VOLT DIV C1VD PE S 4 gt CHANNEL 2 VOLT DIV C2VD lt 5 000 MV to 12 500 V gt The range of the Volts div setting is limited to 2 5 Volts per division in the case of 50 Q coupling Note that this value corre
194. ourier Waveform Processing Option WP02 V 2 06FT 11 24 F i Number of RIS SS Time div Nyquist Points 1 250 kHz 50 SS 2 msec 1 250 kHz 125 SS 5 msec 1 250 kHz 250 SS 10 msec 1 250 kHz 500 SS 20 msec 1 250 kHz 1250 SS 50 msec 1 250 kHz 2500 SS 100 msec 1 250 kHz 5000 Ss 200 msec 1 250 kHz 12500 Ss 0 5 sec 1 250 kHz 25000 SS 1 sec 2 500 kHz 50 Ss 1 msec 2 500 kHz 100 SS 2 msec 2 500 kHz 250 SS 5 msec 2 500 kHz 500 SS 10 msec 2 500 kHz 1000 SS 20 msec 2 500 kHz 2500 SS 50 msec 2 500 kHz 5000 SS 100 msec 2 500 kHz 25000 SS 0 5 sec 6 250 kHz 125 SS 1 msec 6 250 kHz 250 Ss 2 msec 6 250 kHz 625 ss 5 msec 6 250 kHz 1250 SS 10 msec 6 250 kHz 2500 SS 20 msec 6 250 kHz 6250 SS 50 msec 6 250 kHz 12500 SS 100 msec 6 250 kHz 25000 SS 200 msec 12 500 kHz 50 SS 0 2 msec 12 500 kHz 125 SS 0 5 msec 12 500 kHz 250 SS 1 msec 12 500 kHz 500 SS 2 msec 12 500 kHz 1250 SS 5 msec 12 500 kHz 2500 SS 10 msec 12 500 kHz 5000 SS 20 msec 12 500 kHz 12500 ss 50 msec 12 500 kHz 25000 SS 100 msec 25 000 kHz 50 ss 0 1 msec 25 000 kHz 100 Ss 0 2 msec 25 000 kHz 250 SS 0 5 msec 25 000 kHz 500 SS 1 msec 25 000 kHz 1000 SS 2 msec 25 000 kHz 2500 SS 5 msec 25 000 kHz 5000 SS 10 msec 25 000 kHz 25000 SS 50 msec Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 25 Fryquist 62 500 62 500 62 500 62 500 62 500 62 500 62 500 62 500 125 000 125 000 125 000 125 000 125 000 125 000 125 000 125 000 125 000 250 000 250 000 250 000 250
195. p is the computation of FFT using a fast implementation of the DFT Discrete Fourier Transform k N 1 1 Cage n k X a x X V n N k k 0 where SL is a complex array whose real part is the modified source 5 time domain waveform and whose imaginary part is 0 Xa is the resulting complex frequency domain waveform j 2 WN N lt 6 N is the number of points in Xk and Xa The generalized FFT algorithm implemented in the 9400A works on N which need not be a power of 2 The fifth step is the division of the resulting complex vector X by the coherent gain of the window function to compensate for the loss of the signal energy due to windowing This compensation provides accurate amplitude values for isolated spectrum peaks The real part of Xa is symmetric about the Nyquist frequency that is Ri Ry n while the imaginary part is anti symmetric that is Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 13 6 7 It can be considered that the energy of the signal at some frequency n is distributed 50 50 between the first half and the second half of the spectrum the energy at frequency 0 is completely contained in the O term The sixth step is the elimination of the redundant part of the results Only the first half of the spectrum Re Im 0 to the Nyquist frequency is kept R 2 R sc pau T 0 n n t oq a zZ INIA gt 2 NAN The seventh and last step is the computation of th
196. peated addition with equal weight of recurrences of the source waveform Whenever the maximum number of waveforms is reached the averaging process stops The averaging process may be interrupted by switching the trigger mode from NORM to SINGLE 29 or by turning the function trace OFF 48 Averaging will continue when these actions are reversed The currently accumulated average may be reset either by changing an acquisition parameter such as input gain offset or coupling trigger condition or time base or by pressing the RESET push button 41 twice in quick succession remember that FUNCTION E or F must be selected The number of currently averaged waveforms is displayed in the Displayed Trace Field V in Figure 4 1 of the corresponding function or of its expansion Whenever the maximum number of sweeps is reached a larger number of sweeps may be accumulated by simply changing the maximum number of sweeps in the setup menu In this case care must be taken to leave the other parameters unchanged otherwise a new averaging calculation is started Summed averaging may be performed over CHANNEL 1 or 2 FUNCTION F may also average over FUNCTION E therefore allowing averaging over functions Whenever a waveform containing overflow or under flow values is to be added to an average unknown values will be added The user may choose the action to be taken If Artifact Rejection is OFF any overflows are set to the maximum 256 po
197. pressing either the Previous 6 or Next VALUE 7 The Baud rate is selected from a set of values in the range 110 through 19 200 baud The possible settings of character length are 6 7 and 8 parity none even or odd and number of stop bits 1 and 2 Manual Operation S267 Plotter Setup 9 The 9400A has been designed to permit direct interfacing of the oscilloscope with four of the most popular plotters via the rear panel RS 232 C dedicated plotter port or the optional GPIB IEEE 488 port When the 9400A is connected toa plotter via the GPIB port with no host computer in the configuration the oscilloscope s rear panel thumb wheel switch must be set to the Talk Only mode address gt 31 decimal and the plotter to the Listen Only mode Plotter setup configuration is similar to configuration of the RS 232 C ports see Section 5 2 6 above Previous FIELD Next Number of inetalled pene 2 Previous PLOT SIZE Next Paper size A4 ISO US11 8 5 ee The plot area will be lees than 229mm e 160 mn Return PLOTTING PLOTTER SET UP MENU Figure 5 17 Manual Operation 5 28 The user can choose the following parameters Plotter Type Plotter Port Plot Speed Number of Installed Pens Plot Size Non standard HP7470A or compatible Philips PM8151 or compatible Tektronix or Graphtec FP 5301 RS 232 C or GPIB IEEE 488 Normal or Low Speed 1 to 9 ISO A5 US 8 5 x 5 5 I
198. proving the performance of its products While physical modifications can be implemented quite rapidly the corrected documentation frequently requires more time to produce Consequently this manual may not agree in every detail with the accompanying product There may be small discrepancies in the values of components for the purposes of pulse shape timing offset etc and occasionally minor logic changes Where any such inconsistencies exist please be assured that the unit is correct and incorporates the most up to date circuitry Service Procedure Products requiring maintenance should be returned to the Customer Service Department or authorized service facility If under warranty LeCroy will repair or replace the product at no charge The purchaser is only responsible for the transportation charges arising from return of the goods to the service facility For all LeCroy products in need of repair after the warranty period the customer must provide a Purchase Order Number before any equipment which does not operate correctly can be repaired or replaced The customer will be billed for the parts and labor for the repair as well as for shipping Return Procedure To determine your nearest authorized service facility contact the factory or your field office All products returned for repair should be identified by the model and serial numbers and include a description of the defect or failure name and phone number of the user and i
199. quency only the shape of the peak will change However the effective frequency resolution i e the ability to actually resolve two signals having close frequencies is further limited by the use of window functions The ENBW value of all windows other than the rectangular is greater than Af i e greater than the bin width Table 11 3 lists the ENBW value for the windows implemented Fast Fourier Waveform Processing Option WP02 V 2 06FT 11 17 Leakage Observe the Power Spectrum of a sinusoidal waveform having an integral number of periods in the time window i e the source frequency equals one of the bin frequencies using the Rectangular window The spectrum contains a sharp component whose value reflects accurately the source waveform s amplitude For other input frequencies this spectral component is lower and broader The broadening of the base of the peak stretching out into many neighboring bins is termed the leakage It is due to the relatively high side lobes of the filter associated with each frequency bin The filter side lobes and the resulting leakage are reduced when one of the available window functions is applied The best reduction is provided by the Blackman Harris and the Flat Top windows However this reduction is offset by a broadening of the main lobe of the filter Numbers of Points In the 9400A FFT is computed over the number of points Transform Size selected in the Redefine Menu The effective numb
200. r i e 0 04 V div O 8 div 25 7 div 50 6div ees 200 O div 225 1 div 250 S EE heane 400 8 div See Section 7 10 1 for an example of how data values are converted to volts in processed data records Input channel coupling at acquisition 0 DC 50 QR 1 Ground 2 DC 1 MQ 3 Ground 4 AC 1 MQ Attenuation of external probe must have been set up manually or by remote control 0 1 1 10 2 100 3 1000 This value is already absorbed into the fixed vertical gain position 0 it serves only as a reminder here Bandwidth limit at acquisition 0 off 1 on Time base at acquisition coded as an integer 4 2 nsec div 5 nsec div 6 10 nsec div 7 20 nsec div Sip was 34 20 sec div 35 50 sec div 36 100 sec div Remote Operations 7 44 7 7 8 lt ESC gt gt If the output buffer becomes full the 9400A overwrites the last character DEFAULT THIS COMMMAND IS IMMEDIATELY EXECUTED 9 lt ESC gt R Sets the 9400A to REMOTE 10 lt ESC gt L Sets the 9400A to LOCAL 11 lt ESC gt C The 9400A executes a DEVICE CLEAR command clears the input and output buffers all the status bytes except STB 4 and all the corresponding masks It then terminates plotting and data transmission and resets the RS 232 C REMOTE port to DEFAULT setting THIS COMMMAND IS IMMEDIATELY EXECUTED 12 lt ESC gt T The 9400A executes a TRIGGER command see Section 7 6 9
201. r CHANNEL 1 or 2 FUNCTION F may also generate extrema over FUNCTION E therefore allowing extrema over functions Arithmetic The arithmetic waveform processing options consist of the basic arithmetic functions performed on two source waveforms on a data point per data point basis Different vertical gains and offsets of the two sources are automatically taken into account However both source waveforms must have the same time base and both must have either INTERLEAVED OFF or INTERLEAVED ON The trigger point may be different in the two source waveforms although such a case would usually give results that are difficult to interpret The first source waveform may be multiplied by a constant factor in the range 01 to 9 99 and be offset by an additional constant in the range of 9 99 times the volts division setting of the first source waveform Functions This option consists of the following mathematical functions on single waveform sources negation square Square root integral and differentiation The first source waveform may be multiplied by a constant factor in the range 01 to 9 99 and be offset by an additional constant in the range of 9 99 times the volts division setting of the first source waveform Smoothing Five options are available 1 3 5 7 and 9 point smoothing 1 point smoothing consists of adding adjacent data points to each other with equal weight The data points of the source waveform are considere
202. r computer terminal control and plotter connection Asynchronous up to 19200 baud GPIB port IEEE 488 Configured as talker listener for computer control and fast data transfer 400 kilobytes sec maximum ASCII or binary The address switches are on the rear panel It includes LeCroy MS02 MASP IBM PC based software for mass storage and remote control applications For further details on MASP software please refer to the MS01 02 data sheet PROBES Probe calibration 976 Hz square wave 1 V p p 1 Standard probes Two model P9010 x10 attenuating pas sive probes with 10 MQ input impedance in parallel with a 5 5 pF capacitance Probe power Two power outlets on the rear panel provide 15 V and 5 V DC for active probes GENERAL Temperature 5 to 40 C rated to 50 C operating Humidity 80 EMI Immunity The 9400A complies with the following stan dards IEC 801 VDE 0871 FCC PART 15 and SEV Safety standards The 9400A complies with the following IEC 348 ASE 3453 and VDE 0411 Power required 110 or 220 V AC 48 to 65 Hz 200 W Battery backup NiCd batteries maintain front panel set tings for 6 months minimum Dimensions HWD 19 2 x 36 5 x 46 5 cm 7 1 2 x 14 3 8 x 18 3 8 inches Weight 14 kg 30 Ibs net 20 kg 44 Ibs shipping Warranty 2 years OPTIONS FOR THE 9400A 9400AOP01 1 DC high precision option A certificate of traceability is provided with this option 9400AOP03 Printe
203. r drive for HP 2225 ThinkJet WAVEFORM PROCESSING 9400AWP01 AND 9400AWPO2 Routines are called and set up via menus Extensive signal processing in both time and frequency domains is provided OF SIGNALS SEC Sweeps sec EXECUTION TIME Sec FFT by optional firmware packages These include FFT spectrum analysis arithmetic functions integration differentiation square root square averaging continuous and summation and smoothing as well as Extrema monitoring For additional information refer to data sheets WPO1 and L i U AN A 5000 10000 50000 120 PA I 100 90 80 70 60 500 1000 RECORD LENGTH no of points With option WP01 installed the 9400A becomes a fast signal averager both summation and continuous As many as 100 000 points sec are averaged with record lengths chosen by the user up to a maximum of 32 000 The graph above displays the relationship between record length and the number of signals sec averaged 50 125 250 625 1250 2500 6250 12500 25000 RECORD LENGTH Points FFT execution time as a function of record length including window cal culations and display generation is expressed in the graph above WAVEFORM PROCESSING PACKAGE INCLUDING AVERAGING INTEGRATION DIFFERENTIATION LeCro y WP01 WAVEFORM PROCESSING FIRMWARE L FOR MODEL 9400A DIGITAL OSCILLOSC
204. race is OFF TIME MAGNIFIER TM lt gt lt O top l gt TIME MAGNIFIER is applied to the SELECTed trace It may only be applied to traces EXPAND A or EXPAND B The value 0 corresponds to no expansion Each increment of 1 corresponds to the next lower time base value relative to the original trace The value 6 therefore allows an expansion by a factor of 100 The 9400A sets the VALUE ADAPTED bit if an out of range positive value is given Negative values generate a semantic error The 9400A sets the ENVIRONMENT ERROR if the SELECTed trace is OFF if the SELECTed trace is neither EXPAND A nor EXPAND B HOR POSITION HP lt 7 gt lt 0 0000 DIV to 10 0000 DIV gt when the source trace corresponds to a single waveform acquired in single shot or with INTERLEAVED ON lt 1 to max gt when the source trace corresponds to multiple waveforms acquired in SEQNCE The parameter indicates the number of the sequence to be displayed max depends on the selected number of segments see SEGMENTS HOR POSITION will be applied to the SELECTed trace It may only be applied to traces EXPAND A or EXPAND B The parameter in the range O to 10 divisions corresponds to the CENTER of the intensified region on the original trace The smallest possible step is 0 0004 div The 9400A sets the VALUE ADAPTED bit if an out of range value is given Interleaved Sampling or Single Shot if a posi
205. rd from the top soft key on the left hand side of the graticule This command is only accepted if the string delimiter has been changed from the default value lt gt to lt gt with the command COMM STRDELIM 33 The default value lt gt 34 see Section 7 6 7 Remote Operations 7 19 KEY 1 Restart Instructs the 9400A to display the message Restart next to the first soft key Here the default string delimiter is used 11 SCREEN SCR lt gt lt REMOTE RM gt lt LOCAL LC gt or SCREEN SCR lt ON gt xk lt OFF gt ak or SCREEN SCR lt INTENSITY INT gt O to 170 kk lt GRID INTENSITY GI gt x 2 allows the user to know the status of the screen REMOTE and LOCAL select the control mode of the screen When the 9400A is set to REMOTE the screen remains under LOCAL control allowing the operator to adjust the display intensity The screen itself must be put into the REMOTE state using the command SCREEN SCR lt ON gt before the commands marked with are valid ON and OFF turn the screen ON an OFF respectively When the 9400A is being used to capture transients automatically without a user looking at the display the display may be turned off This improves the response time of the instrument since display generation which may take up to 100 msec is suppressed INTENS and GRID INT set the display intensity The 9400A sets the VALUE ADAPTED bit if a
206. re symmetric about the point k N 2 mid screen on the 9400A where they all have a peak amplitude of 1 0 ee r wrar e a ey ee es ee ee mbe ee ey ee ee eee ey ce ge es ee es ee ee ee ee ee ey ee ee ee ee ee es ee ee ee ee ee es ee ee ee P ae k d EE y g g hr Sy rey ey ec m cs Ss ce m iar ce ey es es ce ee es es ee ee i ee ee ee ee Window type ao ay ay Rectangular 1 0 0 0 0 0 von Hann 0 5 0 5 0 0 Hamming 0 54 0 46 0 0 Flat Top 0 281 0 521 0 198 Blackman Harris 0 423 0 497 0 079 mn gir mr mir r e a e g a a mre wrar m t n r n ee fias ir mre har My t vf 501 ee mr m ee mn rare r lt y B rre o Abat u rk ee ee ce ee ee mr r e b ee bb ee oe Fast Fourier Waveform Processing Option WPO2 V 2 06FT 11 20 11 7 SS rr rh PE S ar in r ro n a a n rn n r r r n n m ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee Window type Highest Scallop ENBW Coherent side lobe loss gain dB dB bins dB Rectangular 13 3 92 1 0 0 0 von Hann 32 1 42 1 53 6 02 Hamming 43 1 78 1 37 5 35 Flat Top 44 0 01 2 96 11 05 Blackman Harris 6 7 1 13 1 71 7 53 e mri m i sce m ne es 4 ec ce ee ce m ee ee err d ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee m Errors and Warnings Certain combinations of source waveform properties and processing functions may result in an error or raise a warning The appropriate message is displayed at the top of the 9400A screen On Error processing
207. resolution 1 mHz to 50 MHz Nyquist frequency range 25 mHz to 2 5 GHz Frequency scale factors 5 mHz div to 500 MHz div in 1 2 5 sequence Frequency accuracy 0 008 at center lobe Horizontal expansion up to 100 times Cursors Differential arrows and absolute crosshair provide frequency and related amplitude measurements AMPLITUDE AND PHASE General Amplitude accuracy see window functions table below Signal overflow A warning indication is provided at the top of the 9400A display when the input signal exceeds the ADC range DC suppression selected via the menu ON OFF removes DC component prior to FFT execution Cursors Horizontal bars provide differential amplitude measurements Number of traces Time domain and frequency domain data can be displayed simultaneously up to 4 traces Spectrum Display Formats and Scaling Real spectrum in V div zero base line at O div center of screen imaginary spectrum in V div zero base line at 0 div Power spectrum in dBm Power spectral density in dBm Frequency Domain Averaging up to 200 spectra for power PSD or magnitude Log display applies to power and PSD spectra in 10 5 2 or 1 dB div 80 dB display range Markers at left edge of screen give absolute dBm reference 0 dBm is 1 mW into 50 9 Phase Phase range 180 degrees to 180 degrees Phase accuracy 5 degrees Phase scale factor 50 degrees div Zero base line 0 div center of screen
208. rleaved with 50 sweeps at 4 nsec interval 5 interleaved with 100 sweeps at 2 nsec interval 3 SEQNCE with 8 segments 4 SEQNCE with 15 segments 5 SEQNCE with 31 segments 6 SEQNCE with 62 segments 7 SEQNCE with 125 segments 8 SEQNCE with 250 segments Trigger coupling at acquisition O DC 1 HF REJ 2 LF REJ 3 AC Trigger mode at acquisition 0 SINGLE 1 NORM 2 AUTO 3 SEQNCE Trigger source at acquisition EXT 10 1 EXT 2 LINE 3 CHAN 2 4 CHAN 1 Trigger slope at acquisition O negative 2 window 1 positive Trigger level at acquisition The coding depends trigger source 7 45 on the trigger slope and on the Remote Operations POS 18 22 24 26 28 Size 32 bit 16 bit 16 bit 16 bit 16 bit Meaning Positive or negative trigger slope Parameter CHAN 1 2 EXT 0 5 00 div 2 00 V 25 4 00 div 1 60 V 50 3 00 div 1 20 V 100 1 00 div 40 V 125 U div 0 V 150 1 00 div 40 V 200 3 00 div 1 20 V 250 5 00 div 2 00 V In EXT 10 the trigger voltages are multiplied by 10 Window trigger Parameter CHAN 1 2 EXT lt 25 90 div 20 V 25 50 div 20 V 50 1 00 div 40 V 100 2 00 div 80 V 125 2 50 div 1 00 V 150 3 00 div 1 20 V 200 4 00 div 1 60 V 250 5 00 div 2 00 V In EXT 10 the trigger voltages are multiplied by 10 Note that the window size is limited to 5 div or 20 V due to the na
209. rrespective of the vertical offset of the trace displayed on the grid Note that setting the marker cursor to 0 time interval provides a visual indication of the trigger point Main Monu LTT LEP BESHE NTN Chi gt 2 Y T div Gme Ch2 20nV Trig OQdiv CHAN 1 i 8 DISPLAYED TRACES SHOWING MARKER CURSOR INTERVAL BETWEEN TRIGGER POINT and CURSOR as well as ALPHANUMERIC READOUT of the AMPLITUDE of the TRACES Figure 5 5 Manual Operation 5 15 TIME Cursors button 17 Generate a downward pointing and an upward pointing arrow on the currently displayed traces permitting accurate differential time voltage and frequency measurements Time cursors are displayed as follows Main Menu NOA TA SEE A TEA 99 FARN E AN TTT Tore L T Salta r COPEL Ch At 1 76 ms f 568 1 kz T div 5ms Ch2 20mV Trig O0div CHAN 1 Chamel i 19 mV DISPLAYED TRACE SHOWING TIME CURSORS their VOLTAGE DIFFERENCE their TIME DIFFERENCES and the CORRESPONDING FREQUENCY Figure 5 6 Note Measurement resolution with Time cursors is 0 2 of full scale 10 divisions In the case of expanded traces time cursors are displayed on the trace providing up to xl00 higher resolution measurement 0 002 maximum depending on the setting of TIME MAGNIFIER control 43 Use of the waveform expansion facility is therefore recommended to ensure the most accurate time measurements Manual Operation 5 16
210. s an additional 512 kilobytes random access memory for accumulation computation and waveform buffering It permits the accumulation of up to 1 000 000 waveforms of 32000 points each All processing occurs in waveform memories E and F which may be displayed on the screen by pressing FUNCTION E F buttons Whenever one of the FUNC TIONS E or F or their expansions EXPAND A or B is turned on the corresponding waveform processing is executed and the result displayed SIGNAL AVERAGING WP01 offers two powerful high speed signal averaging modes to improve signal to noise ratio and provide more accurate measurements Averaging increases the dynamic range by several bits allowing the sensitivity to reach pVolts Summed averaging consists of the repeated addition Complex Functions Computes integration dif ferentiation square square root and negation on single waveforms stored in the 9400A memory loca tions CH1 CH2 C D and E Waveform data can be multiplied by constants Smoothing Allows two smoothing modes to reduce unwanted noise on single events Mean value smoothing down to 50 segments N point smoothing with up to 9 point filter Vertical Expansion Provides vertical scale expan sion by a factor of up to 10 in signal averaging mode Chaining of Operations Automatically chains two operations Example F E Average CH1 CH2 An indefinite number of operations can be per formed sequentially either man
211. s echoing of characters received by the 9400A COMM TRAILER OFF disables trailer RS CONF 9 13 10 0 0 selects half duplex mode with lt TAB gt decimal9 as a talk character lt CR gt lt LF gt decimal 13 and 10 as lt END gt message string no echo character and no turnaround delay Whenever the computer interrogates the 9400A to get one or several responses or to get one more blocks of data it sends the command followed by lt CR gt optional and lt LF gt and then by lt TAB gt lt TAB gt puts the 9400A into the talker mode and instructs the 9400A to send one response or one block of data to the computer To get more information or more blocks lt TAB gt must be re sent Example The computer wants to know time base and bandwidth limit settings Computer sends TIME DIV BANDWIDTH lt CR gt lt LF gt lt TAB gt 9400A ansvers TIME DIV 2 00E 03 lt CR gt lt LF gt Computer sends lt TAB gt 9400A answers BANDWIDTH ON lt CR gt lt LF gt The characters which put the 9400A into a talker mode and the characters of the lt END gt message string must not be the same If they were lt END gt would purge the second part of the output Remote Operations 7 40 If turnaround delay is necessary i e if a certain amount of time is necessary between the time the 9400A receives the trigger character and the time it sends the first character the last parameter of the RS CONF must be non zero Example R
212. s for the acquired Signal as well as an indication of the position of the VAR sensitivity vernier 28 The symbol gt appears when the vernier is not in the detent position i e not in the fully clockwise position Whenever Measurement Cursors 16 17 18 are activated absolute or relative waveform voltage data are displayed in this field A frame formed around one of the upper six signal sources in the Displayed Trace field indicates which of the traces is to be acted upon during manipulation of the various display controls 39 through 43 Display Layout 4 2 4 6 Message Field VI Messages appearing in field VI indicate the 9400A s current acquisition status or report improper manipulation of the front panel controls The following figure illustrates a typical message displayed in the Message field INTERLEAVED ie possible at lt 2 pe div Main Menu oe DE a ae E S ST H fc he ool Chi ZO nW d T div 5ps Ch2 6 V Trig 3 08div CHAN 1 EXAMPLE of MESSAGE FIELD DISPLAY Figure 4 2 kkKKKKKK xNOTE KKKKKKKK In the following sections Roman numerals in parentheses refer to the display field numbering scheme in Figure 4 1 Arabic numerals relate to the numbering scheme used to refer to front and rear panel controls and connectors in Figures 1 1 and 1 2 Display Layout 4 3 5 1 1 SECTION 5 MANUAL OPERATION Front Panel Controls Vertical Input Connectors 21 BNC type connectors are us
213. setups including WPO1 menus can be stored and recalled by the menu buttons at the left side of the 9400A screen ELTETE fa mV ee V v im I I tdimv CA city CHAN 1 The 1 V amplitude sine wave in channel 1 upper trace is squared function E 1 1 lower trace and then integrated functions F E The value of the integral between the two cursors is 4 00 pV s the RMS value can be calculated with the formula RMS 1 f V2dt In this case RMS 1 4uV2s 1 2 0 707 V At 8 us 44 nVa l i Ul LYa EA a kA a La a t x 4 fx sual i l L mY 1 l i l 1 j igh 2 Wo ledive nna Lh a iig 1 Iv CHAN 1 A fast negative going signal at 5 nsec div upper trace recorded in Random Interleaved Sampling mode is inverted and stored in memory C lower trace Integral and differential are shown in function E and function F The area under the inverted curve is measured by first defining the area with the time cursors and then reading the value of C In this case 11 44 nVs LeCROY EUROPEAN HEADQUARTERS Route du Nant d Avril 101 P O Box 341 1217 Meyrin 1 Geneva Switzerland Telephone 022 823355 Telex 419058 Fax 022 823915 LeCROY CORPORATE HEADQUARTERS 700 Chestnut Ridge Road Chestnut Ridge NY 10977 6499 Telephone 914 578 6097 800 5 LeCroy 532 769 TWX 710 577 2832 Fax 914 425 8967 LeCroy Innovators in Instrumentation Other sales and service representatives
214. shable from that of the components below the Nyquist frequency In the 9400A the FFT definition menu displays the effective Nyquist frequency You should select the time base and Transform Size resulting in a Nyquist frequency higher than the highest significant component in the time domain record To help you choose suitable settings for FFT analysis a table of Nyquist frequencies is given in Section 11 8 Coherent Gain The coherent gain of a filter corresponding to each window function is 1 0 O dB for the Rectangular window and less for other windows It defines the loss of signal energy due to the multiplication by the window function In the 9400A this loss is compensated Table 11 3 lists the values for the windows implemented ENBW Equivalent Noise Bandwidth For a filter associated with each frequency bin ENBW is the bandwidth of an equivalent rectangular filter having the same gain at the center frequency which would collect the same power from a white noise signal as the filter considered In Table 11 3 ENBW is listed for each window function implemented and is given in bins Filters Computing an N point FFT is equivalent to passing the time domain input signal through N 2 filters and plotting the outputs of the filters along the frequency axis The spacing of filters is Af 1 T and the bandwidth depends on the window function used see Frequency bins Fast Fourier Waveform Processing Option WPO2 V 2 06FT 11
215. signal having a 10 to 20 nsec period to CHAN 2 input 21 In the Main Menu press the Recall PANEL push button 5 Recall the Default panel setup 9 Return to the Main Menu by pressing the Return push button 10 Call the Panel Status menu 2 Set CHAN 2 Fixed VOLTS DIV as appropriate 27 Set CHAN 2 OFFSET to 0O mV Set CHAN 2 COUPLING to DC 50 Q Adjust CHAN 2 VAR vernier 28 as appropriate Adjust TRIGGER DELAY control 34 to 40 0 Pre Adjust TRIGGER LEVEL control 33 to 00 division Set TRIGGER COUPLING to AC 30 Basic 9400A Waveform Measurements and Operating Procedures 8 2 8 2 13 Set TRIGGER SOURCE to CHAN 2 23 14 Set TRIGGER SLOPE to POS 25 15 Set TRIGGER MODE to NORM 29 16 Set TIME DIV control 36 to 5 nsec div 36 17 At this point INTERLEAVED SAMPLING RIS is ON 18 Set BANDWIDTH LIMIT to OFF 50 19 Return to the Main Menu by pressing the Return aah button 10 20 Set CHAN 2 to ON and CHAN 1 to OFF 49 21 Set DUAL GRID mode to OFF 14 Resulting Display ee ET C OF AA V D D a or Channel 2 222 0 mV Ch 1 gt 50 mV Menu OFF T div B na Ch2 gt 20nv Trig OO0div CHAN Z Figure 8 2 A waveform is displayed in the center of your screen Signal acquisition is performed in the Random Interleaved Sampling mode Single Shot Acquisition Acquisition of a single 100 nsec wide pulse In this case the pulse generator is not free running It must be in extern
216. sponds to the 9400A input gain It does not take probe attenuation factors into account The 9400A sets the VALUE ADAPTED bit if an out of range value is given Examples CHANNEL 2 VOLT DIV 500 MV Sets channel 2 to 500 mV div C1ivD 5 Sets channel 1 to 500 mV div C2VD 120 MV Sets channel 2 to 120 mV div by choosing 100 mV div fixed gain and setting the variable gain to the required value 11 CHANNEL 1 ATTENUATION C1AT gS E gt CHANNEL 2 ATTENUATION C2AT lt 1 gt lt 10 gt lt 100 gt lt 1000 gt Indicates or selects the attenuation factor of the probe 12 CHANNEL 1 OFFSET C10F Se gt CHANNEL 2 OFFSET C20F lt 8 00 DIV to 8 00 DIV gt The 9400A sets the VALUE ADAPTED bit if an out of range value is given Remote Operations 7 6 3 13 14 15 CHANNEL 1 COUPLING C1CP lt gt CHANNEL 2 COUPLING C2CP lt AC 1 MOHM AIM gt k lt DC 1 MOHM D1M gt lt GND gt lt DC 50 OHM D50 gt BANDWIDTH BW lt gt lt ON gt lt OFF gt STOP Stops the acquisition of a signal This command may be used to return the 9400A from the armed state to the triggered state when the trigger is absent It generates records similar to those produced in the AUTO trigger mode It is also useful to stop a SEQNCE acquisition when the number of triggers available is insufficient to fill all sweeps Upon receipt of the STOP command the 9400A displays
217. sportation and insurance charges arising from the return of products to the servicing facility LeCroy will return all in warranty products with transportation prepaid This warranty is in lieu of all other warranties expressed or implied including but not limited to any implied warranty of merchantability fitness or adequacy for any particular purpose or use LeCroy shall not be liable for any special incidental or consequential damages whether in contract or otherwise Assistance and Maintenance Agreements Answers to questions concerning installation calibration and use of LeCroy equipment are available from the Customer Service Department 700 Chestnut Ridge Road Chestnut Ridge New York 10977 6499 U S A 914 578 6097 and 101 Route du Nant d Avril 1217 Meyrin 1 Geneva Switzerland 41 22 782 33 55 or your local field engineering office LeCroy offers a selection of customer support services For example maintenance agreements provide extended warranty and allow the customer to budget maintenance costs after the initial two year warranty has expired Other services requested by the customer such as installation training on site repair and addition of engineering improvements are made available through specific Supplemental Support Agreements General Information 1 1 1 3 1 4 1 5 Documentation Discrepancies LeCroy is committed to providing state of the art instrumentation and is continually refining and im
218. ssible value of the ADC and any under flows to the minimum 0 The waveform is then added to the average Of course the average will be incorrect at the overflow positions If Artifact Rejection is ON waveforms containing at least one overflow or under flow are rejected from the average i e not added at all If waveforms consistently contain overflows or under flows averaging cannot proceed and the number of accumulated sweeps may stay at zero indefinitely In order to improve the signal to noise ratio even further the 9400A offers the possibility of performing offset dithering When turned on i e when set to gt O least significant bits of the ADC the 9400A adds a small hardware offset to each acquired waveform This offset is different for different waveforms and the values are chosen such that their average is negligibly small The function setup menu allows a choice of the maximum excursion of this offset WPO1 Waveform Processing Option 10 3 10 2 2 When set to the largest possible value of 6 LSB the waveforms are offset by up to 2 vertical divisions remember that a vertical division corresponds to 32 least significant bits of the ADC In this case care must be taken that the waveform to be averaged is contained within 1 5 of a vertical division from the top and the bottom of the display grid otherwise overflows or under flows might occur Whenever dithering is ON the displays of CHANNELS 1 or 2 vary vertica
219. stem configurations includ ing 9400CS01 signal generators power supplies and a computer with accessories and fixtures are quoted on re quest Training User training classes on service and maintenance of the 9400 series oscilloscopes as well as calsoft operation are scheduled regularly CERTIFIED CALIBRATION CS9400 Certified traceable calibration to NBS or any other national standard is obtained by specifying CS9400 when ordering the 9400A caw CERTIFICATE OF fhe standards tho Kalani idon Set tihed national Standards A me U S Nationa oom faceable direc stromans Mocks Socialiong eau of Standargs oc Odwectiy to olho Intex POJ Caty atn Othe Sery aana 08 Jaw gy al ds of Corby THR OF the apat moaca E Gusting tite Cokbrang Or have been archived KR an as L ORO Number to the bd 18 avaiable Re Cray location COSI by JAN ag V ar daia Time and cross hair cursors indicate Hz and dB or volt val ues when an FFT spectrum analysis is made Menus Standard Waveform storage acquisition parameters memory status store recall front panel configurations RS 232 C configuration plotter setup Optional WP01 WP02 averaging arithmetic functions extrema smoothing FFT and frequency domain averag ing REMOTE CONTROL All the front panel controls including variable gain offset and position controls not cursor positioning and ail the in ternal functions are programmable RS 232 C ports Two fo
220. sweep gt transfer ALL data from the host computer to the indicated memory location of the 9400A This command must be followed by the data blocks in the order descriptor data trigger time s See the READ command for an explanation of lt Parameter list gt In general the 9400A decodes and checks each WRITE command it receives and verifies the optional parameters If it receives a WRITE command for a complete waveform WRITE xx the parameters are only checked after the DESCRIPTOR block has been transmitted If the lt intval gt parameter is not 1 intermediate points will be computed with a linear interpolation DESCRIPTOR values are checked for consistency after the entire block has been received If an error is detected the entire block is discarded and the invalid data block has no effect on the currently stored descriptor The same is true for the time block However the waveform DATA values are directly stored into the final buffer during transmission If an error occurs during the transfer the data memory might be only partially filled with the new data The 9400A sets the VALUE ADAPTED bit if a numerical parameter had to be modified during checking if less or more DATA values have been received than were indicated by the numerical parameters after checking and only if the number of DATA values is not greater than the number of values remaining until the end of the sweep buffer The 9400A sets the INVALID
221. t OFF allows automatic calibration ON disables automatic calibration OFF or queries the state of the automatic calibration See Section 9 4 for the conditions under which the 9400A calibrates itself PROBE CAL PC lt AC gt 0 000 V to 5 000 V lt DC gt This command permits generation of a square signal AC witha period of 1 024 msec or a continuous DC level at the specified voltage at the probe test output When the 9400A returns to LOCAL the default calibrator signal of 1 V AC is generated The 9400A sets the VALUE ADAPTED bit if a positive out of range value is given AUTO STORE AS lt gt lt O0to5 gt d This command allows the user to query the 9400A on its AUTOSTORE state or setting of the AUTOSTORE mode AUTOSTORE off automatic storage of CHANNEL 1 into MEMORY C automatic storage of CHANNEL 1 into MEMORY D automatic storage of CHANNEL 2 into MEMORY C automatic storage of CHANNEL 2 into MEMORY D automatic storage of CHANNEL 1 into MEMORY C and of CHANNEL 2 into MEMORY D E Ln amp L K KA Remote Operations 7 6 7 4 5 6 CALL HOST CH N NP N lt 7 lt ON lt OFF This command may be executed even while the 9400A is in LOCAL When the CALL HOST mode is set the 9400A only while it is in LOCAL displays the message Call Host next to the soft key 7 of the Main Menu Whenever this soft key is pressed it will generate a service request SRQ pro
222. t ensure that the corect line voltage has been set Installation eal 3 3 Switching on the 9400A Switch on the 9400A by setting the POWER switch 26 to the ON position An auto calibration takes place and the grid is displayed after approximately 15 seconds Note that the 9400A is reset to the configuration it was in prior being to switched off Installation 3 1 4 1 SECTION 4 DISPLAY LAYOUT The 9400A s CRT area is divided between the centrally located grid and six other fields Traces from the acquisition or reference memories are displayed on the grid A dual grid system is also available by pressing push button 14 see Figure 1 1 The six fields are used to display such information as interactive menu queries and responses current acquisition parameters relative and absolute time and voltage measurements and messages to assist the user DISPLAY LAYOUT Figure 4 1 Menu Field I This field is divided into nine sub fields associated with menu keys 2 10 Each field may display the name of a menu or perform an operation when the related menu key is pressed The lowest field and related Return push button 10 are used to restore the higher menu level Display Layout 4 1 4 3 4 4 4 5 Time and Frequency Field IT When the Marker cursor is activated by pressing push button 18 this field displays the time difference between the Marker cross hair and the point of triggering common for all
223. t d CA9001 Camera using Polaroid film and Hood CA9002 Camera Adapter 35mm with Hood CS9400 Certified Calibration DP9001 Digital Plotter 8 pen A4 size 94XX FC Front Cover OC9001 Oscilloscope Cart P9010 10 1 Oscilloscope Probe P9010 2 10 1 Oscilloscope Probe with 2 m cable P9011 10 1 1 1 Oscilloscope Probe P9100 100 1 Oscilloscope Probe RM9400 Adapter Kit for Rack Mounting SG9001 High voltage Protector TC9001 Transit Case TC9002 Protective Cover TC9003 Transit Case for 9400A and Mass Storage US SALES OFFICES 1 800 5 LeCroy automatically connects you to your local sales office WORLDWIDE Australia Scient Devices Pty Ltd 03 579 3622 Austria Dewetron Elektr Messgerate GmbH 0316 391804 Benelux LeCroy B V 31 4902 89285 Canada Rayonics Sci Inc W Ontario 416 736 1600 E Ontario Manitoba 613 521 8251 Quebec 514 335 015 W Canada 604 293 1854 Denmark Lutronic Aps 42 459764 Finland Labtronic OY 90 847144 France LeCroy Sarl 1 69073897 Germany LeCroy GmbH 06221 49162 North 0405 42713 Greece Hellenic S R Ltd 01 721 1140 India Electronic Ent 02 4137096 Israel Ammo 03 453157 Italy LeCroy Srl Roma 06 302 9646 Milano 02 2940 5634 Japan Toyo Corp 03 279 0771 Korea Samduk Science amp Ind Ltd 02 468 04914 Mexico Nucleoelectronica SA 905 5693 6043 New Zealand E C Gough Ltd 03 798 740 Norway Avantec AS 02 630520
224. t exists and has an associated mask The commands STB MASK and TSTB act on all 6 status bytes or masks including STB 2 SOFTKEY PRESSED Status Byte STB 3 This status byte contains the coded value of the most recently pressed soft key Whenever the MASK 3 is non zero and the code in STB 3 is set to a non zero value the SOFTKEY PRESSED bit DIO 3 in STB 1 is set Codes 0 No soft key pressed 1 9 One of soft keys 1 9 pressed in REMOTE 10 CALL TO HOST soft key pressed in LOCAL INTERNAL STATE Status Byte STB 4 This status byte contains status bits reflecting the internal state of the 9400A Since the internal states cannot be directly controlled reading this byte does NOT reset it Whenever a bit of this status byte gets set and the corresponding bit in MASK 4 is also set the INTERNAL STATE bit DIO 4 in STB 1 is set Bits 0 TRIGGERED cleared when the 9400A is armed i e acquiring data and set when the 9400A is triggered i e not acquiring data 1 OVERLOAD1 set when channel 1 is in overload reset otherwise 2 OVERLOAD2 set when channel 2 is in overload reset otherwise Ji FIRST SEQNCE sweep triggered Note Overloads are cleared by removing the overloading signal from the input and by returning the input coupling to 50 Q Overloads never occur with 1 MQ coupling OPERATION COMPLETE Status Byte STB 5 This status byte contains status bits reflecting the identity of the operation which has bee
225. te an RQS bit i e to generate a Service Request MASK 5 4 Sets the mask of the OPERATION COMPLETE byte STB 5 to the binary value 00000100 allowing the propagation of the calibration done bit to the OPERATION COMPLETE bit of STB 1 MASK 6 1 Sets the mask of the ERROR byte STB 6 to a non zero value allowing the propagation of errors to the ERROR bit of STB 1 CAL Instructs the 9400A to calibrate itself After approximately 500 msec the 9400A sets the calibration done bit in the OPERATION COMPLETE byte STB 5 Since this bit is demasked it is propagated to the OPERATION COMPLETE bit of STB 1 And because this bit is also demasked it sets the RQS bit and generates a Service Request interrupt on the GPIB bus TRIG LEVEL Instead of responding to the Service Request the host computer sends this illegal command It generates a semantic error and sets the ERROR byte STB 6 to the value 40 Since this byte is demasked the ERROR bit in STB 1 is also set and because this bit is also demasked it may set the RQS bit However the RQS bit is already set At this point the host computer may choose to respond to the Service Request in either of the following ways l Remote Operations 7 53 If it responds with a Serial Poll it will read the binary value 01010000 i e the RQS bit and the OPERATION COMPLETE bit Upon execution of the Serial Poll these two bits are reset in STB 1 However the 9400A remembers that another bit
226. ter the 9400A and the Plotter are all Connected Together on a GPIB Bus Option OPO2 only In this configuration the computer controls the GPIB bus and the devices that are on the bus such as the 9400A and the plotter The 9400A cannot directly send plot data to the plotter even when it is in LOCAL It is the task of the computer to organize the data transfer The following sequence should be followed Basic 9400A Waveform Measurements and Operating Procedures 8 19 8 15 1 The computer sets the 9400A into REMOTE 2 The computer sets itself to Talker and the 9400A to Listener and sends the command SCREEN DUMP 3 The computer organizes the transfer between the 9400A and the 4 plotter in one of the ways described below The choice depends on the computer GPIB controller software The computer tells the 9400A to talk and the plotter to listen It puts itself in Standby Mode while waiting for EOI that will be set by the 9400A when the plot is finished or The computer tells the 9400A to talk and the plotter to listen It puts itself in Listener mode while reading but NOT while storing the plot data or The computer tells the 9400A to talk and sets itself to Listener It reads AND stores the plot data Afterwards it sets itself to Talker and tells the plotter to Listen and sends the stored data to the plotter Notice that a larger amount of data has to be stored up to 50 kilobytes if all the traces are on The
227. tes data values with a sign The last parameter selects the separator between numbers The default is lt COMMA gt Remote Operations gt 6 Example With COMM FORMAT L BYTE UNSIGNED SHORT CRLF a block will be L 2 123 34 Whereas with COMM FORMAT L BYTE UNSIGNED SHORT it is L 2 123 34 The 9400A sets the ENVIRONMENT ERROR if the A format is selected while the 9400A is controlled through RS 232 C COMM BLOCKSIZE CBLS 1 The data is transmitted in one block only and the END block I is neither sent nor received COMM BLOCKSIZE CBLS 0 The data is transmitted in one block only The END block 1 will be sent and must be received This is the default block size COMM BLOCKSIZE CBLS 40 to 32000 The data is transmitted in one or more blocks The END block I will be sent and must be received with the purpose of marking the end of the block transfer This command selects the maximum block size for data block transfers READ WRITE SETUP The specified block size includes all data bytes including preamble and postscript The 9400A sets the VALUE ADAPTED bit if the numerical parameter is positive but less than 40 it will be adapted to 40 or if it is greater than 32000 it will be adapted to 32000 COMM STRDELIM CSDE 1 to 127 Defines the ASCII character that the 9400A recognizes as a string delimiter The default is the character lt gt whose decim
228. the VALUE ADAPTED bit in status byte 1 is set 2 INTERLEAVED IL lt gt lt ON gt lt OFF gt N 3 Enables or disables Interleaved Sampling The 9400A sets the ENVIRONMENT ERROR if ON command is sent while the time base is greater than 2 US if OFF command is sent while the time base is less than 50 NS TRIG DELAY TRD lt gt lt 0 00 to 100 00 gt gt lt 0 04 NS to 1000000 S gt Positive format pre trigger Negative format post trigger delay Valid delay values correspond to 0 to 10000 time base divisions in steps of 1 50 of adivision If the TIME BASE is changed the delay remains the same or may change just slightly due to rounding provided that it does not exceed 10000 divisions Note In the case of post trigger delay the remote value is negative while the corresponding value displayed on the screen is positive Remote Operations 4 5 6 7 The 9400A sets the VALUE ADAPTED bit if a positive out of range value is given if a negative value corresponding to more than 10000 divisions is given TRIG LEVEL TRL gt gt lt 5 00 DIV to 5 00 DIV gt when the oscilloscope is set to one of the internal trigger sources CHANNEL 1 or CHANNEL 2 lt 2 00 V to 2 00 V gt when the oscilloscope is set to in the EXT trigger source lt 20 0 V to 20 0 V gt x when the oscilloscope is set to the EXT 10 trigger s
229. tive out of range value is given SEQNCE Negative or zero values generate a semantic error Remote Operations 8 9 10 The 9400A sets the ENVIRONMENT ERROR if the SELECTed trace is OFF if the SELECTed trace is neither EXPAND A nor EXPAND B REDEFINE RDF r 2 lt CHANNEL 1 C1 lt CHANNEL 2 C2 lt MEMORY C MC lt MEMORY D MD NP NP NP N N S T T X Redefines the source of the SELECTed trace to be CHANNEL 1 CHANNEL 2 MEMORY C or MEMORY D The SELECTed trace must be EXPAND A or EXPAND B The 9400A sets the ENVIRONMENT ERROR if the SELECTed trace is OFF if the SELECTed trace is neither EXPAND A nor EXPAND B MESSAGE MSG lt String to be displayed gt The string may be up to 43 characters in length The message is displayed in the Message Field above the graticule see Section 4 6 Example MESSAGE Apply probe to J11 5 then press READY Instructs the 9400A to display the message between the string delimiters on the line above the graticule The push button READY does not exist on the 9400A but any of 9 soft keys may be defined as such with the command KEY KEY lt 1 to 9 gt lt String to be displayed gt x The string is displayed in the Menu Field see Section 4 1 next to the soft key selected with the first parameter The string may be up to 11 characters in length Examples KEY 3 READY Instructs the 9400A to display the message READY next to the thi
230. traces in EXPAND A or B is turned ON the corresponding waveform processing is executed Whenever the trace and its expansion is turned OFF the processing is suspended This is true even for remote control The display can be turned off by remote control in order to gain speed command SCREEN OFF Section 7 6 3 however even in this case the corresponding function trace must be turned ON although nothing is displayed on the screen FUNCTIONS E and F are waveforms that exist independently of i e in addition to the acquisition memories of CHANNELS 1 and 2 and of the reference memories C and D On the display they are treated similarly to memories C and D i e the vertical display gain and the vertical position can be modified but not the horizontal position and the time magnifier Of course they can be expanded by redefining the source waveform of the traces EXPAND A or B Two different processing functions can be executed simultaneously FUNCTIONS E and F may be read by remote control just like the other traces with the additional option of reading 16 bit data values and as with Channels 1 or 2 they may be stored in reference memories C or D by pressing the STORE push button 1 Waveform processing functions operate on one or two source waveforms which may be CHANNEL 1 or 2 Memory C or D FUNCTION F may also operate on FUNCTION E Since the results of the processing functions can be stored in the reference memories and since FUNCT
231. trigger is not available Common Expand Mode Section 5 1 4 discusses independent expansion of single traces to display a magnified portion of the waveform from CHAN 1 and or CHAN 2 Memories C and or D or of Function E and or F if the 9400A is equipped with WPO1l1 Waveform Processing firmware However in certain applications it is convenient to be able to move the intensified region along two different traces simultaneously This is the purpose of the Common Expand mode In this mode it is possible to either synchronize the intensified regions of the two source signals or to maintain a fixed time interval between them in which case the intensified regions for each trace will move horizontally at a fixed interval See Section 8 11 for an example of intensified regions shifting on two traces expanded in the Common Expand mode In the Common Expand mode when the user is examining two expansions at a fixed interval he may re synchronize them by pressing the RESET button 41 both expansions are shifted to the center of the grid Turning the Horizontal POSITION control 39 until both of the intensified regions move off the screen will also re synchronize them In the Common Expand mode only the Horizontal POSITION control 39 and TIME MAGNIFIER control 43 act simultaneously on the intensified regions on both the EXPAND A and B signal source while the VERT GAIN control 42 and Vertical POSITION control 40 act independently on eac
232. ts and Operating Procedures 8 4 8 3 Trace Expansion Expand A B Using the same 100 nsec signal and front panel settings described in Section 8 2 but with your pulse generator free running this time perform the following procedure 1 Set push button 14 to DUAL GRID mode 2 Press EXPAND A 46 in order to expand CHAN 1 trace If the source for signal expansion shown in the Displayed Trace field V is not X Chan 1 you must perform the following procedure to redefine the expansion signal source to CHAN 1 a Press the REDEFINE push button 45 to display the Redefine Source menu in the Menu Field I b Press push button 1 in order to redefine CHAN 1 as the new source for the expanded X Chan 1 display At this point the new source for the expanded X Chan 1 line in the Displayed Trace Field V is updated to X Chan 1 and all or a portion of CHAN 1 trace is intensified 3 Turn the TIME MAGNIFIER control 43 to adjust the magnification factor length of the intensified section as desired e g 5 nsec 4 Displace the intensified section by adjusting Horizontal POSITION control 39 and position it on the risetime of your pulse 5 Position the expanded trace in lower grid by adjusting the Vertical POSITION control 40 6 Adjust VERT GAIN control 42 if required At this point the digitized points are clearly seen every 10 nsec 7 Set INTERLEAVED SAMPLING to ON The equivalent sampling frequency is
233. ts the 9400A to transmit 100 data values of Channel 1 starting 1000 values to the right of the beginning of the screen Only every 5 data value is transmitted i e 4 out of 5 values are omitted Instructs the 9400A to transmit all data values of sweep 5 from the SEQNCE data record in memory D If memory D is not a SEQNCE record the last parameter is ignored and the command would be interpreted as READ MD DA resulting in the transmission of all visible data of the memory D Instructs the 9400A to transmit the waveform descriptor data and time s of Channel 2 This is the most complete and safest way to archive the visible part of a waveform The host computer can restore the complete waveform in memories C or D with the command WRITE MC followed by the transmission of the data records Remote Operations READ CHANNEL 2 32000 Instructs the 9400A to transmit the waveform descriptor data and time s of Channel 2 including all invisible data values on the left hand side of the screen The address 32000 is usually out of range but the 9400A automatically adapts to the closest legal value This complete data record is restored in memory C with the command WRITE MC 32000 5 WRITE WT lt MEMORY C DESC MC DE gt lt MEMORY D DESC MD DE gt X transfer the waveform descriptor from the host computer to the indicated memory location of the 9400A This command must be followed by t
234. ture of the trigger hardware Trigger delay at acquisition in units of 02 of TIME DIV relative to the left hand side of the screen 500 10 div i e 100 Z pre trigger 0 O div i e 0 Z pre trigger 50 1 div i e post trigger of 1 TIME DIV 500000 10000 div i e maximum post trigger of 10000 divisions Number of measured data points per division at the time of acquisition This number is independent of whether the user reads all or a fraction of the data values by specifying lt intval gt larger than 1 See READ command Address of first measured data point relative to the left hand edge of the screen Address of last measured data point relative to the left hand edge of the screen Internal use Remote Operations 7 46 7 8 Pos Size Meaning 30 16 bit Internal use 32 16 bit Internal use 34 8 bit Data processing of this record 99 no processing raw data 0 averaging 1 extrema 2 arithmetic 3 functions 4 smoothing 35 8 bit Unused 36 149 Additional parameters reserved for the description of the waveform processing if any Format of Trigger Time s The trigger time is the time interval between the occurrence of the trigger and the measurement of the next data sample This time is always expressed in units of 2 14 of the nominal sampling interval and spans integer values from 0 to 2 14 1 16383 The transmission format is a 16 bit integer with the most significant byte s
235. ually or via remote control Remote Control Controls remotely all front panel settings as well as all waveform processing options via either GPIB or RS 232 C interfaces Color Archiving Copies screen in color using a wide range of digital plotters with equal weight of recurrences of the selected source waveform Whenever the required number of waveforms is reached the averaging process will stop The total number of waveforms to be accumu lated can be selected between 10 and 1 000 000 sweeps in a 1 2 5 sequence Signals exceeding the dynamic range of the 9400A s 8 bit ADC at any point may be automatically rejected to ensure valid summed averaging results The user may also choose to dither the program mable offset of the input amplifier Dithering uses slightly different portions of the ADC for successive waveforms so that the differential non linearities are averaged As a result in a low noise application the measurement precision and dynamic range are improved Continuous averaging sometimes called exponential averaging consists of the repeated weighted average of the source waveform with the previous average This mode of averaging is a continuous process The effect of previous waveforms gradually tends to zero Relative weighting factors can be chosen from 1 1 to 1 127 This averaging mode is most useful for setting up measurements or observing noisy signals that change with time EXTREMA MODE Trackin
236. uiring the next trace Whenever the 9400A is in the NORM or AUTO trigger mode data are continuously acquired and the display rapidly updated All modifications in acquisition parameters are thus followed quickly by subsequent waveform acquisition which results in their appearing to the user as changes to the CHAN 1 or CHAN 2 display TRIG D and READY LEDs 31 The TRIG D LED indicates whenever the digitizing has stopped normally after a valid trigger The READY LED indicates that the trigger circuit has been armed and the 9400A is currently digitizing input signals Upon receiving a valid trigger Signal it will continue digitization until the trigger conditions have been satisfied and will then display the acquired waveform DELAY 34 Adjusts the degree of pre or post trigger delay when recording signals in the acquisition memories Delay operation is via a single continuously rotating knob Turning this knob slowly allows minute adjustment of the trigger point turning it quickly results in rapid trigger point movement The DELAY control enables pre trigger adjustment displayed in 4 Pre trigger adjustment up to 100 full scale and post trigger adjustment up to 10 000 divisions in 0 02 division increments are available Manual Operation 5 11 5 1 5 The pre trigger indicator is displayed by an upward pointing arrow on the bottom graticule line the post trigger indicator is displayed in decimal fractions of a second pre
237. ur 9400A 9 1 500 points resolution E TVIT ATIN grid ATT Ch 1 gt 2 V7 T div 2ye Ch2 1 V Trig 1 48 div CHAN i Figure 9 1 To make the best use of the ADC s dynamic range and therefore the most accurate amplitude measurements the displayed signal should completely fill the display grid The fully calibrated and continuously adjustable input signal conditioning permits you to meet this requirement easily without loss of calibration As an overlapping display of two full scale waveforms could become quite confusing the 9400A provides a dual grid option to be used in applications where both channels are used simultaneously display dual grid 2 x 250 points resolution Ch T div 2ye Ch2 1 V FIGURE 9 2 Trig 1 48 div CHAN 1 Getting the Most Out of Your 9400A 9 3 Accurate Time Measurements Two deep acquisition memories each storing 32000 points provide the unprecedented time resolution of the 9400A In order to match the time base settings a maximum of 25000 digitized points are displayed on the screen with a resolution of 500 display points A compacting algorithm showing all minimum and maximum values ensures that no information is lost in the display of a trace Time cursors can be positioned accurately on any one of the 500 display points of a compacted trace The corresponding measurement accuracy is 1 500 or 0 2 digitized waveform x A max
238. v a OF Feet Ommy renl Coupling AC 1MO TRIGGER peepee Delay 10 0 Pre Set Ch2 Level 00 div Attenuator Coupling DC BG Source CHAN 1 Slope Mode NORMAL Return PLOTTING Chan 2 EO mv 50 0 aY OmV AC 1 M Time div 5 me Tine pre 200 ne Points div 2500 Interleaved Saupling OFF BW Limit OFF Por BENCE 6 Trigger Level has cbeolute meaning with DC Coupling only PANEL STATUS MENU Figure 5 10 Vertical parameters Fixed V div The current setting of the front panel Vertical Sensitivity control 27 with the VAR vernier in the fully clockwise position is indicated Total V div The current setting of the front panel Vertical Sensitivity control 27 plus the additional sensitivity range up to x 2 5 of the Fixed V div setting is 28 counterclockwise 5 20 provided by turning the VAR vernier Manual Operation Trigger parameters Delay In Figure 5 10 the indicated trigger delay is 10 Pre meaning that when in Main Menu the Delay arrow is positioned one division to the left of the center of the grid In the case of a post trigger delay setting this would be indicated in decimal fractions of a second i e amp 4 00 msec Level The trigger level indicated in Figure 5 10 is displayed in terms of grid divisions The 9400A displays the current trigger level setting in divisions when in the internal trigger mode It displays the setting in Volts when in the external trigger mode T
239. veform Processing Functions Additional Values in the Descriptors of Processed Waveforms Vertical Scaling Units Index of Topics Fast Fourier Waveform Processing Option YPO V 2 06FT 11 11 11 amp LA KA KA E OONA amp gt Processing Capabilities Modification to WPO1 Functions FFT Processing Examples Remote Control of FFT Processing Remote Commands Additional Values in the Descriptors of FFT Processed Waveforms FFT Application Hints Some practical suggestions Relationships of 9400A FFT output waveforms to the FFT computation steps Computation Speed of FFT FFT 9400A Glossary Errors and Warnings Table of Nyquist Frequencies References Index of Topics Appendix 10 8 10 13 10 15 10 17 11 1 11 7 11 11 11 12 11 15 11 16 11 21 11 22 11 29 11 30 LeCroy 9400A DUAL 175MHz OSCILLOSCOPE ee er ee ee a T a O H O H H 0 OIO OJO OJO OJO SCREEN INTENSITY GRID INTENSITY DUAL GRID CURSOR MEASUREMENT MODE VOLTAGE TIME MARKER 9400A FRONT PANEL Figure 1 1 100Ms s 5Gs s 44 43 42 41 TIME MAGNIFIER oa VERTICAL CHANNEL 1 OFFSET O VOLTS DIV CURSOR POSITIONS REFERENCE POSITION CHANNEL 2 OFFSET J VOLTS DIV m COUPLING x TO LF REJ HF REJ DIFFERENCE Kac re ar E aine race Prs AB ong TE aar or d ra Re ck rer C e s CER c KURE ge Ratan n PLETE 6668664666668 eeeeeeeoeee eoeoeeeseoe
240. vided that the masks of status byte 3 and status byte 1 are correctly set see Section 7 6 8 The purpose of this command is to allow the operator in an ATE setup Automatic Test Engineering to call the host computer even while the 9400A is in LOCAL mode i e while the operator is permitted to change the 9400A front panel settings IDENTIFY ID 7 Request for identification message may be omitted The 9400A will send the message LECROY 9400A V xxxxxx where xXxxxxx is the software version number WAIT When the 9400A is acquiring a signal the WAIT command stops any command interpretation until the oscilloscope has been triggered Communication Format Command 1 2 COMM HEADER CHDR lt OFF gt lt SHORT SHO gt lt LONG LG gt Defines the header format in the 9400A character strings in response to queries Options are no header short or long formats The default is SHORT When the header is OFF the suffixes of the dimensioned parameters are also suppressed COMM TRAILER CTRL Defines the trailer format in the 9400A character strings in response to queries OFF is only possible in RS 232 C control The default is CRLF Note In remote control through GPIB the last character is sent with the EOI line set Remote Operations 7 31 3 4 The 9400A sets the ENVIRONMENT ERROR if command is CTRL OFF while controlling via GPIB COMM HELP CHLP lt OFF gt lt REM PORT RP
241. w commands The 9400A assumes that the user is not interested in the answers to previous commands since he is sending another command message rather than reading the responses Command Synchronization with Data Acquisition Some remote commands cannot be executed at all times e g it is not possible to read channel 1 or channel 2 while the oscilloscope is armed and waiting for a trigger since the memories of the two channels are continuously being written into The user can avoid such situations entirely by only executing single shot acquisitions TRIG MODE SINGLE and by checking that bit 0 of status byte 4 TRIGGERED bit is set to one indicating that the acquisition is complete before sending the READ command Another way is to send the command to read channel 1 or channel 2 The 9400A automatically defers the execution of this command until a waveform has been acquired It is thus possible to also read waveforms while the instrument is in the trigger modes NORM or AUTO i e practically on the fly Remote Operations 7 6 AA A AMM MMM M M M M N W T T T 7 4 7 7 4 8 Execution of the command is also deferred when using some other remote control commands in particular the command STORE channel 1 or channel 2 and the special command WAIT whose sole purpose is to force such a synchronization See Section 7 6 6 Other Remote Commands Character Strings Strings may be displayed see MESSAGE and KEY commands sent toa
242. waveform reaches 3 divisions in amplitude Storing and Recalling Front Panel Setups Storing repetitive signals 1 Follow the same procedure as in Section 8 1 applying the probe calibrator signal 2 Press the STORE PANEL 4 push button Basic 9400A Waveform Measurements and Operating Procedures 8 9 8 8 At this point the listing of 7 possible front panel storage locations appears in the MENU FIELD 3 Press the push button adjacent to the storage location you have selected e g 2 All the front panel settings are now stored 4 Set CHAN 1 Fixed VOLTS DIV to 20 mV 28 and TIME DIV 36 to 2 msec Your display is now half the amplitude and the sweep speed 2 5 times faster 5 Press the STORE PANEL push button 4 6 Press push button 3 to store the new panel settings 7 Press the RECALL PANEL 5 push button 8 Press push button 2 At this point the first setting stored is recalled with the corresponding display Pressing push button 3 will recall the second setup Signal Storage in Memories C D I Storage of CHAN 1 Waveform into Memory C Apply the same signal as in Section 8 1 I and recall the front panel setup by pressing push buttons 5 and 2 in that order Procedure 1 Stop acquisition by setting the TRIGGER MODE 29 to single 2 Press STORE push button 1 to call the Store Trace menu 3 Store CHAN 1 into Memory C 2 4 Set CHAN 1 to OFF by pressing push button 49 5 Set MEMO
243. y selected oscilloscope parameters the user must first set the 9400A to remote use This is done by entering lt ESCOR i e the character lt ESC gt followed by upper case R Programming Example Set the Time Base to 2 msec Programming Procedure 1 Enter TD 2MS lt CR gt upper or lower case characters Other possible character formats are TIME DIV 2 MS lt CR gt upper or lower case characters TD 2E 3 lt CR gt upper or lower case characters TD 002 lt CR gt upper or lower case characters Resulting Display Observe the Abridged Panel Status field in the lower right hand portion of the screen while the above character sequence is entered via the terminal keyboard When lt CR gt is pressed you will see the currently displayed time base setting change to 2 msec In order to return the 9400A to Local use type lt ESC gt L i e the character lt ESC gt followed by upper case L at which point you will be returned to the 9400A s initial menu i e the menu which appears at unit power up Basic 9400A Waveform Measurements and Operating Procedures 8 15 305 310 315 320 325 330 III Example of a Typical Program A short BASICA interactive program showing how to initialize communication between a 9400A and an IBM PC AT is given belov SAMPLE PROGRAM FOR LINKING THE LECROY 9400A DSO TO AN IBM PC AT VIA THE RS232C ASYNCHRONOUS COMMUNICATIONS INTERFACE U AUTHOR M SCHUMACHER i CL

LECROY 9400A Operating

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