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Tektronix 2246 User's Manual

1. eu i Controls Connectors and Indicators 2246 Operators 3 C0000 OF p H 000000100 J nereeo gt En ri 6083 04 Figure 3 2 CH 1 and CH 2 Vertical Controis and indicators UNCAL Indicator indicates that either or both VOLTS DIV VAR controis are out of their calibrated detent position BW LIMIT Button Reduces the bandwidth of the vertical deflection system to between 17 MHz to 23 MHz when the button light is on Full vertical deflection bandwidth is available when the BW LIMIT button light is off INVERT Button inverts the Channel 2 input signal when the INVERT button light is on Both the Channel 2 input signal in ADD mode and the Channel 2 trigger signal pickoff are also inverted A down arrow symbol appears on the readout between the Channel 1 and Channel 2 VOLTS DIV switch settings to indicate INVERT mode is on COUPLING Buttons Select the method of coupling input signals to the Channel 1 and Channel 2 vertical attenuators and indicate the selection made GND Disconnects the input signal and grounds REV APR 1987 the input of the associated vertical attenuator to provide a zero ground reference voltage display The input to the vertical attenuator is grounded when the AC and the DC button lights are both off A ground symbol rh appears on the right side of the associated VOLTS DIV readout display The ground symbol also appears after th
2. The 2246 Portable Oscilloscope aT Band Aa i 4 nn een Section 1 2246 Operators SPECIFICATION INTRODUCTION The TEKTRONIX 2246 Oscilloscope is a portable 100 MHz bandwidth instrument having a four channel vert ical deflection system The horizontal deflection system provides calibrated sweep speeds from 0 5 to 20 ns per division and delayed sweep features The trigger system provides stable triggering over the full bandwidth of the vertical deflection system Alphanumeric crt readouts of the vertical and horizontal scale factors are displayed at the bottom of the screen On screen vertical and horizontal cursors provide accurate voltage time frequency and phase measurements with measurement value readouts displayed at the top of the crt The 2246 is microprocessor controlled and features menu driven waveform measurement processes The flexi bie measurement features of the oscilloscope include a choice of either voltmeter measurements for Peak Peak Peak to Peak and average DC values of the sig nal applied to a selected measurement channel or position able cursors for measuring voltage difference time difference frequency and phase Measurement tracking trigger level tracking and ground tracking SmartCursors that provide visual feedback to the user may be placed on the displayed waveforms Menus called up to make the measurement mode choices are displayed at the right side of the crt next t
3. 3 dB cutoff fre quency of 20 Hz 0 5 division of composite sync will achieve a stable display 10 Hz 20 divisions referred to the appropriate vertical input This range is sufficient to allow triggering at any point on a displayed waveform for all modes except ADD In ADD the combined range of the two position controls exceeds the trigger level range making it possible though unlikely to pull a signal on screen for display but fail to trigger on it due to insufficient trigger level range 0 3 of reading 10 of one vertical division increases A Sweep holdoff time by at least a factor of 10 1 5 Specification 2246 Operators Characteristics Table 1 1 cont Performance Requirements FUNCTIONS WITH DIGITAL READOUT VOLTMETER FUNCTIONS DC VOLTS Accuracy Normal Mode Rejection Ratio PLUS or MINUS PEAK Accuracy Full Bandwidth 25 Hz to 25 MHz Greater Than 25 MHz to 100 MHz Accuracy Bandwidth Limited 25 Hz to 10 MHz Gated Region Minimum Width when gated PK PK VOLTS Accuracy Full Bandwidth 25 Hz to 25 MHz Greater Than 25 MHz to 100 MHz Accuracy Bandwidth Limited 25 Hz to 10 MHz Gated Region Minimum Width when gated CURSOR FUNCTIONS i SEC I manually positioned cursors Accuracy l 1 SEC l manually positioned cursors Accuracy VOLTS I manually positioned cursor Accuracy l VOLTS 1 manually positioned cursors Accuracy l PHASE i manually positioned cu
4. Connect exter nal signals to the inputs of Channel 3 and Channel 4 vertical attenuators via DC input coupling only The input connectors are BNC with probe coding ring contacts the same as the Channel 1 and Chan nei 2 connectors The limited choice of deflection factors for the Channel 3 and Channel 4 inputs makes them most useful for the application of digital signal levels and trigger signal input channels In X Y mode signals applied to either or both input connec tors may be selected to provide a vertical deflection Y Axis signal HORIZONTAL See Figure 3 4 for items 24 through 32 POSITION Control Sets the horizontal position of the waveform displays on the crt Clockwise rotation of the POSITION control will move the display to the right X10 MAG Switch Horizontally magnifies the por tion of all the normal sweep displays positioned at the center vertical graticule line by a factor of 10 when the X10 MAG button light is on No action occurs in X Y mode A X10 symbol appears in the readout on the right side of the A SEC DIV display in A and ALT Horizon tal MODE and on the left side of the B SEC DIV display in B Horizontal MODE when X10 MAG is on In X10 MAG mode the fastest display sweep speed is extended to 2ns per division The crt SEC DIV readout reflects the correct display sweep speed for the X10 MAG displays and the unmagnified displays MODE Buttons Up Arrow and Down Arrow and Indicators Se
5. Controls Connectors and Indicators 2246 Operators CH 1 The signal applied to the CH 1 OR X input connector is the source of the trigger signal CH 2 The signal applied to the CH 2 input con nector is the source of the trigger signal CH 3 The signal applied to the CH 3 input con nector is the source of the trigger signal CH 4 The signal applied to the CH 4 input con nector is the source of the trigger signal LINE The triggering signal is obtained from a sample of the ac power source waveform This trigger source is useful when the displayed waveform frequency is time related to the ac power source frequency CPLG Up Arrow and Down Arrow Buttons and Indicators Select the type of coupling of the input trigger signal to the trigger signal amplifier and indi cate the coupling selected as directed by the A B SELECT button DC Couples de and all frequency components of a triggering signal to the trigger circuitry DC coupling is useful for most signals but it is especially useful for providing a stable display of low frequency or low repetition rate signals NOISE REJ Noise Reject Couples all fre quency components of the input signal to the trigger circuitry but increases the peak to peak signal amplitude required to produce a trigger event NOISE REJ coupling is useful for improving stabil ity when the trigger signal is accompanied by low level noise HF REJ High Frequency Reject
6. 6 18 REV APR 1987 wt I r H tou ae OTHER OPERATING FEATURES USING THE TRACK TRIG LEVEL CURSORS For most general purpose applications the AUTO LEVEL Trigger MODE provides the user with the easiest method to obtain stable waveform triggering When infor mation regarding the actual trigger level setting is needed to set special triggering levels for NORM or SGL SEQ triggering the user may use the TRACKING CURSORS features of the oscilloscope The TRACK TRIG LVL cur sors provide both a visual indication of location and a numeric readout of the Trigger LEVEL control setting in ALT Horizontal MODE with the A Intensified and the B Delayed traces both displayed the A and the B TRACK TRIG LVL cursors will be displayed see Figure 6 16 The A Trigger LEVEL may be set when the trigger controls are directed to the A Trigger system by the A B SELECT switch and the B Trigger LEVEL may be set when the trigger controls are directed to the B Trigger system The Trigger LEVEL cursor will be displayed when enabled if the following conditions exist 1 The Trigger SOURCE is either CH 1 or CH 2 selected directly or VERT SOURCE and 2 The Trigger SOURCE channel is displayed and 3 The Trigger CPLG is DC NOISE REJ or HF REJ and 4 The Trigger mode is AUTO LEVEL AUTO NORM RUNS AFTER or SGL SEG Additionally the A Trigger LEVEL cursor is displayed in A and ALT Horizontal MODE and the B Trigger LEVEL curso
7. CH2 CH2 CH2 CH3 CH3 CH4 CH4 ADD ADD TO A CHANNEL MENU BACK TO DELAY CHANNEL MENU my ting delay time channels a channel that is selected in the menu is turned on if not previously selected and it remains displayed when deselected as the measurement source channel Any channel traces turned on that are not wanted in the display must be turned off using the VERTI CAL MODE buttons if no measurement is active pressing the SET MEAS MT CHANNEL button causes the message SELECT A MEASUREMENT to appear in the top line of the display for two seconds RECALLING THE LAST MEASUREMENT MODE Press LAST MEAS MT to recall the last selected measurement mode if no measurement mode is active The LAST MEAS MT button may also be used to reinitial ize an active measurement mode A press of the button cancels the active measurement and then recalls it in its initialized state This feature is quite useful for returning VOLTS cursors to their initialized positions after they have been adjusted away CH1 CH2 VOLTMETER Press CH1 CH2 VOLTMETER to display the choices of menu 1 shown in Figure 6 1 NOTE if a single channel is selected for display that is the default measurement source channel if both CH 1 and CH 2 are being displayed the default measure ment source channel upon each initialization is CH 1 Use the SET MEAS MT CHANNEL function to assign CH 2 as the measurement channel Turn off the CH1 display i
8. Figure 5 1 Probe Compensation 5 2 NOTE Refer to the instruction manual supplied with the probe for more detailed information about the probes and adjustment procedure VERTICAL DEFLECTION CHECK The CALIBRATOR output signal may be used to check the Channel 1 and Channel 2 vertical deflection system in the following procedure 1 Set the instrument controls to obtain a baseline trace as described in Initial Setup 2 Connect the two 10X probes supplied with the instrument to the CH 1 OR X and CH 2 input connectors scale factor readout switches to 0 1 VOLTS DIV for the attached 10X probes 3 Connect both probe hook tips to the CALIBRATOR output connector 4 Set the bottom of the trace of the CALIBRATOR square wave signal to a convenient horizontal graticule line with the Vertical POSITION control 5 Check for a five division display of the CALIBRA TOR square wave signal TIMING CHECKS The time measurement cursors may be use to check the accuracy of the horizontal deflection system 1 Preset instrument controls and obtain a baseline trace as described in Initial Setup Vertically center the baseline trace 2 Press the CURSORS button to call up the Cursor Measurement Mode menu on the ert and select l SEC l function for measuring time difference by pressing the Menu Select button opposite the menu label 3 Align the reference cursor to the second vertical graticule line using the l OR DELAY
9. Section 7 2246 Operators OPTIONS AND ACCESSORIES INTRODUCTION This section contains a general description of instru ment options and accessories available at the time of pub lication of this manual To obtain additional information about instrument options and accessories consult the current Tektronix Product Catalog or contact your focal Tektronix Fieid Office or representative OPTIONS AO A5 INTERNATIONAL POWER CORDS Instruments are shipped with the detachable power cord option ordered by the customer Descriptive informa tion about the international power cord options is provided in Section 2 Preparation for Use The following list identifies the Tektronix part numbers for the available power cords Option AQ North American 115 V Power cord 74 inches 161 0230 01 Option A1 Universal Euro Power cord 2 5 m 161 0104 06 Option A2 UK Power cord 2 5 m 161 0104 07 Option A3 Australian Power cord 2 5 m 161 0104 05 Option A4 North American 240 V Power cord 2 5 m 161 0104 08 Option A5 Switzerland Power cord 2 5 m 161 0167 00 REV NOV 1987 STANDARD ACCESSORIES gt The following standard accessories are provided with each instrument Part Number 2 Probes 10X 1 5 meter with accessories P6109 1 Power cord Option A0 A5 As ordered gt Power cord clamp 343 1213 00 1 Operators Manual 070 6083 00 1 Operators Guide 070 6082 00 1 Crt implosion shieid blue plastic instalied
10. TEK wma Product Group 46 d 2246 i PORTABLE OSCILLOSCOPE OPERATORS J I 1 I Please Check for l CHANGE INFORMATION at the Rear of This Manual First Printing SEP 1986 Revised MAR 1988 4 Tektronix COMMITTED TO EXCELLENCE Copyright 1986 Tektronix Inc All rights reserved Contents of this publication may not be reproduced in any form without the written permission of Tektronix Inc Products of Tektronix inc and its subsidiaries are covered by U S and foreign patents and or pending patents TEKTRONIX TEK SCOPE MOBILE and are registered trademarks of Tektronix Inc _ Printed in U S A Specification and price change privileges are reserved INSTRUMENT SERIAL NUMBERS Each instrument has a serial number on a panel insert tag or stamped on the chassis The first number or letter designates the country of manufacture The last five digits of the serial number are assigned sequentially and are unique to each instrument Those manufactured in the United States have six unique digits The country of manufacture is identified as follows B000000 Tektronix Inc Beaverton Oregon USA 100000 Tektronix Guernsey Ltd Channel Islands 200000 Tektronix United Kingdom Ltd London 300000 Sony Tektronix Japan 700000 Tektronix Holland NV Heerenveen The Netherlands Mics L L l l l Remnant Certificate of the Manufacturer Import
11. MT initializes in the following manner l VOLTS I and rh VOLTS i cursors and CH1 CH2 VOLTMETER measurements are initial ized to Channel 1 if Channel 1 is displayed other wise to Channel 2 ATIME measurements in ALT and B Horizontal mode initialize to the lowest number displayed channel for the reference delay time and the next lowest number displayed channel for the delta delay if more than one channel is displayed otherwise both delays are on the same channel ADD is considered the highest numbered channel for initialization purposes NOTE if the stored front panel data ever becomes invalid the last measurement is initialized to l SEC i at power on This initialization occurs if the memory backup battery is dead and the first time the instrument is turned on after replacing the battery Refer the instrument to a qualified service person for battery replacement CH1 CH2 VOLTMETER Calls up the voltage measurement menu A selected measurement mode is indicated by an underscored menu label Measurement tracking and ground tracking ee Ser vom m om ne of 8 SmartCursors may be displayed to provide visual feedback to the user about the measure ment points on the displayed signal see CURSORS Only one active measurement at a time is allowed The name of the active measurement and readout of the measurement value are displayed at the top of the screen Available voltmeter menu choices are given
12. With the VERTICAL MODE set to ADD the resulting waveform is the algebraic sum of the signals applied to the Channel 1 and Channel 2 inputs CH 1 CH 2 A plus symbol appears in the readout between the CH 1 and CH 2 VOLTS DIV setting readout to indicate that ADD is active If the CH 2 INVERT feature is turned on INVERT button light on the waveform displayed is the difference between the signals applied to the Channel 1 and Channel 2 inputs Neither CH 1 nor CH 2 waveform needs to be displayed to obtain the ADD trace but any or ALL vertical input channels may be displayed at the same time if wanted by the user When the VOLTS DIV switches of CH 1 and CH 2 are both set to the same setting the total deflection factor in the ADD mode is equal to the deflection factor indicated by either VOLTS DIV readout The l VOLTS I cursors may be used to make voltage measurements on the ADD trace if either CH 1 or CH 2 is displayed along with the ADD trace and of course both CH 1 and CH 2 at the same VOLTS DIV setting If any voltage measurement function is active turning off CH 1 and CH 2 to display the Measurement Processes and Applications 2246 Operators ADD trace by itself causes the message INVALID MEASUREMENT SOURCE to appear and cancels the measurement If calling for a voltage measurement with ADD displayed and neither CH 1 nor CH 2 displayed the CH 1 VERTICAL MODE is turned on and the measure ment is initialized to the
13. 1 10 Characteristics Description m m mr STANDARD INSTRUMENT 7 6 kg 16 8 Ib 8 3 kg 18 2 Ib 11 7 kg 25 8 ib See Figure 1 1 for a dimensional drawing 177 mm 7 in 164 mm 6 44 in 362 mm 14 25in 446 mm 17 6 in 521 mm 20 53 in Forced air circulation no air filter Tek Blue pebbie grain finish painted on aluminum cabinet Aluminum alloy chassis Plastic laminate front panel i Zei ER nase Specification 2246 Operators Table 1 3 Environmental Characteristics Characteristics Description STANDARD INSTRUMENT DE NEE Environmental Requirements Instrument meets or exceeds the environmental requirements of MIL T 28800D for Type Ill Class 3 Style D equipment Temperature Operating 10 C to 55 C 14 F to 131 F 51 C to 71 C 60 to 160 F Tested to MIL T 28800D paragraphs 4 5 5 1 3 and 4 5 5 1 4 except in 4 5 5 1 3 steps 4 and 5 10 C operating test are performed ahead of step 2 51 C non operating test Equipment shall remain off upon return to room ambient during step 6 Excessive condensation shall be removed before operating during step 7 Non operating Altitude Operating To 4 570 m 15 000 ft Maximum operating temperature decreases 1 C 1000 ft above 5000 ft Non operating To 15 240 m 50 000 ft Humidity Operating and Non operating Five cycles 120 hours referenced to MIL T 28800D paragraph 4 5 5 1 2 2
14. 2246 Operators FREQUENCY BEZ sie T LA Ay Th Co Ca a ae E E Sima ieee EME M sk Figure 6 12 Frequency measurement measurement aids Notice that on the left edge of the gra ticule the number 0 10 90 and 100 are etched These marks provide convenient reference points when the signal to be measured is properly set up Use the following pro cedure steps as a guideline in making rise time measure ments 1 Set up the signal to be measured and the front panel controls as indicated in steps 1 and 2 of the PEAK VOLTAGE MEASUREMENT procedure 2 Set the VOLTS DIV and VOLTS DIV VAR controls to provide an exact five division vertical display 3 Use the Vertical POSITION contro to place the negative amplitude of the signal on the 0 reference line and the positive amplitude on the 100 reference line 4 Advance the SEC DIV setting to stretch out the ris ing edge of the waveform as much as possible to improve the cursor placement accuracy see Figure 6 13 NOTE if measuring fall time use negative SLOPE This places the trigger point at the beginning of the Sweep so that when the SEC DIV setting is advanced the slope of interest remains within the viewing area 6 14 5 Increase the A INTEN control if necessary to brighten the beginning of the trace and use the Horizontal POSITION control to place the rising edge of the waveform at the center vertical graticule line 6 Press CURSO
15. Attenuates high frequency triggering signal components above 50 kHz HF REJ coupling is useful for providing a stable display of low frequency components of complex waveforms and eliminates high frequency interfer ence from the trigger signal LF REJ Low Frequency Reject Attenuates low frequency triggering signal components below 100 KHz and blocks the dc component of the trigger signal LF REJ coupling is useful for producing stable triggering on the high frequency components of complex waveforms and rejecting low frequency interference or power supply hum from the trigger signal AC Attenuates trigger signal frequency com ponents below 50 Hz and blocks the dc com ponent of the signal AC coupling is useful for triggering on ac waveforms that have a large de offset REAR PANEL See Figure 3 6 for items 40 through 42 EXT Z AXIS INPUT Connector Connects external signals to the Z Axis amplifier for the purpose of intensity modulating the crt display Signals applied to the EXT Z AXIS INPUT do not affect display waveshape Signals with fast rise times and fall times provide the most abrupt intensity change The active region threshold level is 1 8 V Z Axis voltage above the threshold voltage decreases the intensity and 3 8 V or more produces blanking The Z Axis signals must be time related to the displayed signal to obtain a fixed intensity modulation presentation on the crt Fuse Holder Contai
16. B Triger Source 8 Cursor Channel Lowest numbered channel displayed CH 1 or CH 2 CH 1 CH 1 CH 2 CH 2 CH 3 Not used CH 4 Not used Not used 6 19 Measurement Processes and Applications 2246 Operators To enable the TRACK TRIG LVL cursors press the CURSORS button to call up page one of the menu The last selection in the menu is TO AUTO TRACKING MENU Press the menu select button for that choice to display page 2 with the tracking cursor choices All of the choices TRACK MEASMT TRACK TRIG LVL and TRACK rh may be underlined but they cannot all be displayed at the same time Only two cursors at a time are permitted If enabled but not displayed in a particular waveform omitted cursors will be displayed when a higher priority cursor is turned off TRACK MEASMT cursors take priority over the TRACK rh cursor when TRACK TRIG LVL is also enabled In ALT Horizontal MODE the TRACK rh cursor for the A Trigger signal is higher in priority than the B Trigger Level cursor The cursors displayed when a CURSORS measurement is called take priority over all the Auto Tracking Cursors NOTE The CLEAR DISPLAY button will turn off the TRACK TRIG LVL and TRACK rj cursors if pressed the appropriate number of times To enable either or both of these it is necessary to re enter the CUR SORS menu and reselect them The TRACK MEASMT cursors are also turned off by the CLEAR DISPLAY button but the function is not turned off the T
17. control both cursors are positioned together REV APR 1987 m an oe O yere ye zer ve Ra ve pomem ir ret ern em Operators Checks and Adjustments 2246 Operators H 4 Align the independent A cursor to the 10th vertical Table 5 1 A graticule line using the 1 OR A control for an eight Horizontal Timing Check division cursor position difference A SEC DIV Readout 5 Check that the time difference between the two cur Setting Display sors on the readout is between 794 us and 806 ms To re oe verify other A SEC DIV switch settings check the timing 10 ms 79 4 ms to 80 6 ms for each A SEC DIV setting given the Table 5 1 me 7 94 ms to 8 06 ms i e a 0 4 ms 794 us to 806 us i 10 us 79 4 us to 80 6 us p zz zz iatorra ranana 1 us 7 94 us to 8 06 us as BAER EA ENEA Nee EN BESTER SEE BONES SSH SRAM Barca Aik bo er Fy en mania 1 1 1 1 Ted REV APR 1987 5 3 4 1 painan 4 Sel MEASUREMENT PROCESSES AND Section 6 2246 Operators APPLICATIONS This section is divided into three subsections MENU SYSTEM OPERATION MAKING MEASUREMENTS and OTHER OPERATING FEATURES The first subsection details the ways in which the measurement menus operate The second subsection provides some general applications for using the measurement menus to make measurements on signal waveforms The third subsection discusses use of other oscilloscope features that may aid the user in gener
18. initialized for the MODE switched to A Trigger when selecting A Hor izontal MODE and B Trigger when selecting ALT or B Horizontal MODE No change occurs when switch ing to X Y Horizontal MODE SLOPE Button Selects the slope of the trigger source signal that triggers either the A Sweep or the B Sweep The sweep to which the trigger controls are directed by the A B SELECT switch is triggered from the positive going slope of the trigger signal when the SLOPE button light is on When the SLOPE button light is off the sweep is triggered from the negative going slope of the trigger signal HOLDOFF Control Varies the amount of holdoff time between the end of one A Sweep and the start of the next A Sweep Controls Connectors and Indicators 2246 Operators Full clockwise rotation of the HOLDOFF control increases the holdoff time by at least a factor of ten full counterclockwise rotation produces minimum holdoff time Use this control as an aid in obtaining Stable triggering on aperiodic signals such as com plex digital waveforms LEVEL Controi Sets the amplitude point on the trigger signal at which either the A Sweep or the B Sweep as directed by the A B SELECT button is triggered When the TRIGGER MODE is set to AUTO LEVEL adjusting the trigger level setting to either end of the control range causes the auto level trigger to be recalculated so that the LEVEL control range is lim ited to the peak to peak ampl
19. inputs to the same coupling AC coupling produces some signal phase shift especially at lower frequencies 3 Set the CH 1 VOLTS DIV control to display the reference waveform with about five divisions of amplitude Vertically center the waveform 4 Set the A SEC DIV setting in A Horizontal MODE to display at least one complete reference waveform period and no more than two if possible An excessive number of cycies of the reference waveform in the display reduces the user s ability to make an accurate reference setting Triggering on the negative siope of the sine wave may position the waveform correctly within the graticule area for ease in measurement when viewing a single cycle of the reference signal 5 Press the CURSORS front panel button to display the Cursor measurement choices 6 Select I PHASE A second level phase measurement menu is then displayed with two choices one to continue the phase measurement and one to set the 360 degree reference Assume the present reference setting is not correct if it were selecting l PHASE i again continues the measurement using the present refer ence value 7 Press l SET 360 i to activate the reference set ting function The position of the displayed cursors when l PHASE is again selected defines the full waveform period 360 degrees 8 Position the first vertical cursor to the point that the reference waveform crosses the center horizontal graticule line in
20. setup as for making a time difference measurement as a guideline for making fre The test signal used for illustration purposes shown quency measurements with cursors see Figure 6 12 in Figure 6 10 is a video test signal For triggering on video waveforms select TV LINE Trigger COUPLING and negative Trigger SLOPE for other signal types i 7 no change of COUPLING or SLOPE is required Rise Time Measurements Making rise time or fall time measurement requires some additional signal scaling to use the graticule rise time l Figure 6 10 Instantaneous dc voltage measurement ei Time Difference Use the following procedure steps as a Quideline in making time difference measurements using the l SEC i PULSE PERIOD cursors As with the i VOLTS cursors the i OR DELAY control positions both cursors together and the I OR A control positions the independent cursor 1 Set up the signal to be measured and the front panel controls as indicated in steps 1 and 2 of the PEAK VOLTAGE MEASUREMENT procedure 2 Select a SEC DIV setting that provided no more cycles of the applied waveform than necessary to display the measurement points of interest This is to improve the accuracy of cursor placement for the measurement EEE j NOTE The independent A cursor cannot be positioned in a front of the reference cursor Figure 6 11 Pulse period measurement REV APR 1987 6 13 But Measurement Processes and Applications
21. the A SEC DIV setting appears on the A Sweep and no alternate B Delayed Sweeps are displayed To display the B Delayed Sweep in ALT Mode set the B SEC DIV setting to a faster sweep speed that the A SEC DIV setting B Horizontal deflection occurs at a sweep speed determined by the B SEC DIV switch setting The A B SELECT setting initializes to the B Trigger whenever the B MODE is selected The start of the B Sweep in RUNS AFTER mode or the arming of the B Trigger in any triggered mode is delayed from start the of the A Sweep by a time determined by the setting of the I or DELAY control The B SEC DIV switch setting and the Delay Time Position setting are displayed in the crt readout A question mark is displayed in front of the Delay Time readout if the B Trigger MODE is not RUNS AFTER When a time CUR SOR measurement mode is selected SEC l l 1 SEC I or l e PHASE I is selected the B Trigger MODE switches to RUNS AFTER so that timing measurements may be made X Y The signal applied to CH 1 ORX input connector produces the horizontal X Axis deflection Signals applied to any vertical input 3 5 Controls Connectors and Indicators 2246 Operators Tektronix 2246 6083 06 Figure 3 4 Horizontal Controls and Indicators connector and or ADD may be selected to supply the vertical Y Axis The X Y displays are horizontally positioned by the Horizontal POSITION control and vertic
22. the con trols are changed The measurement readout is especially useful for the CH1 CH2 VOLTMETER measurements because the signal on the selected input channel is con tinually monitored GATED Voltmeter measurements are not permitted in SGL SEQ Trigger MODE Once the final YES NO choice is made the CONFIG URE process is stopped and the SERVICE menu is again displayed Pressing END at any time also stops the CON FIGURE process and returns to the SERVICE menu Press QUIT in the SERVICE menu to get back to operat ing the oscilloscope internal Settings Menu SELF CAL MEASUREMENTS The 2246 has a self characterization feature in the INTERNAL SETTINGS MENU that optimizes accuracy of the CH 1 and CH 2 vert ical channels and the horizontal timing as a single routine A SELF CAL choice is also available in both the CH1 CH2 VOLTMETER menu and the ATIME menu Measurement Processes and Applications 2246 Operators NOTE Calibration constants are stored for use in maintain ing the instrument calibration especially the CHI CH2 VOLTMETER measurements and the tracking cursor placement on the displayed waveforms Performing the SELF CAL readjusts the calibration constants for the present operating tem perature of the instrument If a SELF CAL is done when the instrument is cold the calibration con stants acquired will not be correct when the operat ing temperature is reached The SELF CAL must then be done again after the warm up
23. to account for the operating temperature of the instrument and the calibration constants are stored in memory These start up procedures will not be repeated again unless the calibration constants have been lost from memory A possible reason for this to happen is that the keep alive battery is dead and in need of replacement Refer the instrument to a qualified service person if the battery needs replacement REPACKAGING FOR SHIPMENT it is recommended that the original carton and packing material be saved in the event it is necessary for the instrument to be reshipped using a commercial transport carrier If the original materials are unfit or not available then repackage the instrument using the following procedure 1 Use a corrugated cardboard shipping carton having a test strength of at least 275 pounds and with an inside dimension at least six inches greater than the instrument dimensions 2 if the instrument is being shipped to a Tektronix Service Center enclose the following information show the owner s address name and phone number of a con tact person type and serial number of the instrument reason for returning and a complete description of the service required 3 Completely wrap the instrument with polyethylene sheeting or equivalent to protect the outside finish and prevent entry of harmful substances into the instrument 4 Cushion instrument on all sides using three inches of padding material or
24. true signal waveform Always keep both the ground lead and the probe signal input connections as short as possible to maintain the best waveform fidelity Misadjustment of probe compensation is a common source of measurement error Because of variations in oscilloscope input characteristics probe compensation should be checked and adjusted if necessary whenever a probe is moved from one oscilloscope to another or between channels of a multichannel oscilloscope The probe compensation adjustment procedure is found in Operator s Checks and Adjustments Section 5 of this manual and in the instructions supplied with the probe SCALE FACTOR SWITCHING The VOLTS DIV scale factors are displayed on the CRT The VOLTS DIV readout always reflects the correct scale factor in response to a control change or as a result of change in mr ay T er 3 1 i j the probe attenuation factor when Tektronix coded probes are used Coaxial Cables Cables used to connect signals to the input connectors may have considerable effect on the accuracy of a displayed waveform To maintain the original frequency characteristics of an applied signal only high quality low loss coaxial cables should be used Coaxial cables must be terminated at both ends in their characteristic impedance to prevent signal reflections within the cable Use suitable impedance matching devices REV OCT 1986 Operating Information 2246 Operators EX
25. 337 2775 00 t Fuse 2 A 250 V slow blow 159 0023 00 1 Accessory pouch ziploc 004 0130 00 OPTIONAL ACCESSORIES The following optional accessories are recommended for use with the 2246 Oscilloscope instrument Enhancements Part Number Protective front panel cover 200 3232 00 Attaching accessories pouch 016 0857 00 Protective waterproof viny cover 016 0848 00 Clear implosion shield 337 2775 01 Rackmounting kit 2240F1R DC Inverter power supply 1105 2246 Service Manual 070 6081 01 Options and Accessories 2246 Operators ransportation Aids Carrying strap Portable instrument cart instrument shuttle Cameras Low cost scope camera Motorized camera High performance camera Probes Active probe Power supply for active probe Part Number 346 0199 00 K212 K117 C5 Option 02 C7 Options 03 and 30 C30B Option 01 P6202A 1101A Current probes Environmental probe High voltage probe 1X 10X Passive probe Subminiature 10X probe Ground isolation monitor isolator for floating measurements Viewing Hoods Collapsible viewing hood Binocular viewing hood Polarized collapsible viewing hood Part Number P6021 1 52 m P6022 1 52 m A6302 AM503 A6303 AM503 _ P6008 1 83 m P6008 2 74 m P6063B 1 83 m P6130 2 m A6901 A6902B 016 0592 00 016 0566 00 016 0180 00 De een Tam et eo E
26. AUTO LEVEL TRIGGER SOURCE VERT TRIGGER COUPLING DC HOLDOFF MIN fully counterclockwise MEASUREMENT All off press MODES TRACKING CLEAR DISPLAY CURSORS and three times to MENUS ensure all off Horizontal POSITION A B SELECT 3 Press the CH1 CH2 VOLTMETER button to call up the selection menu and select the PEAK choice Any of the page one choices may be selected as required for the waveform measurement wanted NOTE Depending on the way the CONFIGURE choices of the SERVICE menu have been made the menu will either go off when the measurement selection is made or it will stay on If the menu remains on press the CLEAR DISPLAY button once to remove it from the display See the SERVICE MENU discus sion in this section for further details l 4 The TRACK MEASMT cursor may be displayed with the waveform Pressing CLEAR DISPLAY in the initial setup removes the measurement tracking cursor from the display but does not disable the feature once it has been enabled and the next time a CH1 CH2 VOLTMETER measurement mode is called for the measurement track ing cursor is again displayed 5 Press the CURSORS button and display page 2 of the menu by selecting the TO AUTO TRACKING MENU 6 10 choice Of the three features available in page 2 select both TRACK MEASMT and TRACK rh Menu labels are UNDERLINED when the function is enabled The TRACK rh cursor is especially useful for providing feedback to the user abou
27. BACK TO PREVIOUS MENU Figure 6 1 CH1 CH2 VOLTMETER Menu GATED PEAK Press to measure the most negative screen relative voltage in the gated intensified portion of the waveform GATED PK PK Press to measure the peak to peak voltage in the gated intensified portion of the waveform BACK TO PREVIOUS MENU Returns the first page of the Voltmeter menu CURSORS MEASUREMENTS Press CURSORS to display the measurement choices of menu 1 shown in Figure 6 2 Measurement Processes and Applications 2246 Operators CURSORS SEC 4 H 4 SEC H VOLTS 4 h VOLTS A H PHASE 4 TO AUTO TRACKING MENU CURSORS PG 2 TRACK MEASMT TRACK TRIG LVL TRACK BACK TO PREVIOUS MENU MENU OFF Figure 6 2 CURSOR Measurement Menus The action of the j SEC l I 1 SEC 1 and l PHASE gt SmartCursors is exactly the same as the ATIME measurement choices See the ATIME MENU description for their operation l VOLTS i Measures the equivalent voltage difference between two horizontal cursors in either A Horizontal MODE or X Y Horizontal MODE Both cur sors are positioned by the l OR DELAY control and the delta cursor is positioned by the i OR A control When the VOLTS cursors measurement is first turned on or recalled as a last measurement mode the peak voltages of the source channel signal are measured and one cursor is placed at the most positive peak and the other is placed at the most neg
28. D Starts the A Sweep at the beginning of a video signal field SLOPE polarity must match the composite sync polarity to obtain TV FIELD triggering SGL SEQ Single Sequence Arms the A Sweep for single sequence operation when GEBEN Lua oi ud BEN ee URN selected and with each additional press of the down arrow MODE button after selection When triggered the sweep runs to produce a sin gle sweep of each of the traces as required by the setting of the VERTICAL MODE and TRIGGER MODE switches but each displayed sweep in the sequence requires a distinct A Sweep triggering event The READY front panel light remains on until the final trace in the sequence is completed The readout and cursors may be turned on for only a short period of time at the end of sequence for use with a camera or they may be set to remain on by changing the instrument configuration from the CONFIGURE menu see SERVICE MENU in Section 6 B TRIGGER MODES AUTO LEVEL Sets the range of the Trigger LEVEL control to the peak to peak limits of the signal selected as the B Trigger source if the sig nal amplitude and repetition rate are adequate This mode is very useful for quickly setting the Trigger Levei to obtain stable triggering The B Sweep is triggered as for NORM triggering after all the trigger signal conditions and the delay time set by the t or DELAY control have been met If a trigger is not found trigger source signal amplit
29. EQUENCY COMPENSATION Misadjustment of probe compensation is a possible source of measurement error The attenuator probes are equipped with compensation adjustments To ensure the best measurement accuracy always check probe compen sation before making measurements 5 1 Operator s Checks and Adjustments 2246 Operators 1 Preset instrument controls and obtain a baseline trace as described in Initial Setup Set the CH 1 VOLTS DIV setting to 100 mV 2 Connect the two supplied 10X probes to the CH 1 and CH 2 BNC input connectors l 3 Connect the probe tips to the CALIBRATOR loop and connect the probe ground leads to scope ground 4 Use the CH 1 Vertical POSITION control to center the five division CALIBRATOR square wave in the grati cule area 5 Check the square wave signal for overshoot and rolloff see Figure 5 1 If necessary use the special adjust ment tool supplied in the probe accessory package to adjust the low frequency compensation for a square front corner on the square wave 6 Press the CH 2 VERTICAL MODE button to turn CH 2 on in the display and press the CH 1 Mode button to remove the CH 1 trace from the display 7 Set the CH 2 VOLTS DIV setting to 100 mV and vertically center the CALIBRATOR signal 8 Repeat Step 5 for the second probe on the CH 2 BNC input connector CORRECT FLAT i c anes G ie o tel YER com PENSATED OVERSHOOT UNDER COM PENSATED ROLLOFF 4207 11A
30. ERTICAL See Figure 3 2 for items 10 through 17 10 Channel 1 and Channel 2 POSITION Controls Set the vertical position of the Channel 1 and Channel 2 signal displays Clockwise rotation of a control knob moves the associated trace up counterclockwise rotation moves the trace down In X Y mode the associated POSITION control moves the display vertically MODE Buttons Select the vertical channels for display and CHOP or ALT and ADD Mode for display of the selected channels The buttons will light to indicate the selection made except that for ALT Mode the CHOP ALT button light is off One channel will always be displayed When only one channel is selected for display that channel cannot be turned off CH 1 CH 2 CH 3 and CH 4 Buttons Select any combination of the vertical channels for display by pressing in the appropriate MODE but tons Pressing the button of a displayed channel button lighted removes that channel s trace from the display CHOP ALT Button Chops between the selected input channels at a chopping frequency of approximately 625 kHz when the button is lighted CHOP Mode displays each selected channel in sequence when the button light is off ALT Mode ADD Button Displays the algebraic sum of the Channel 1 and Channel 2 input signals when the ADD button light is on The ADD display is in addition to any other selected channel displays A plus sign appears on the readout between
31. GS menu choices and the CONFIGURE menus choices however are useful to the operator and are explained here Pressing the top and bottom menu selection buttons brings up the SERVICE menu with the selections shown in Figure 6 4 The up and down arrow buttons move the underline seen under SERVICE MENU when first called up through SERVICE MENU DIAGNOSE CONFIGURE INTERNAL SETTINGS MENU FRONT PANEL MENU PROC BOARD MENU QUIT MAIN BOARD MENU Figure 6 4 Service Menu os vr f P the menu choices Press the down arrow twice to under line CONFIGURE When the desired choice is underlined press RUN to start the CONFIGURE process Pressing QUIT exits the SERVICE MENU and returns to the oscillo scope operation mode Configure Menu The CONFIGURE menu contains oscilloscope operating mode features that require infrequent change In the menu a typical screen display is shown in Figure 6 5 Press YES or NO as needed for your method of operation The CONFIGURE menu provides an expandable mode selection menu for possible future changes At this time the operating mode choices to be made are KEEP MENU ON WHEN ITEM SELECTED and KEEP READOUT ON IN SGL SEQ KEEP MENU ON Normally once a final choice in a measurement menu is selected the menu is removed from the display to eliminate clutter when making a measure ment In that case to obtain a new menu selection it is necessary to recall the menu usi
32. Hz at the probe tip Step Response 5 division step Rise Time 10 C to 35 C 3 5 ns or less 35 C to 55 C 3 9 ns or less Delay Match CH 3 to CH 4 Less than 800 ps difference Trace Shift Between VOLTS DIV Settings 1 division or less At least 11 divisions from graticule center Position Range Channel Isolation attenuation of deselected channel 34 dB or more at 100 MHz Channel isolation tested with eight division input signal Input Characteristics Resistance TMQ 1 0 Capacitance 20 pF 4 0 pF Max Input Volts IN 400 V dc peak ac 800 V p p ac at 10 kHz or less VERTICAL DEFLECTION SYSTEM ALL CHANNELS Bandwidth Limit 3 dB bandwidth 20 MHz 15 Low Frequency Linearity Relative to center screen Within 5 Linearity is measured by positioning a two division test signal any where on screen and noting the amplitude change TRACE SEP Control Position Range At least 4 divisions CHOP Mode Clock Rate 625 kHz 10 Delay Match CH 1 or CH 2 to CH 3 or CH 4 Less than 200 ps difference REV FEB 1988 1 3 Specification 2246 Operators Table 1 1 cont Cha Characteristics racteristes O Performance Requirements al HORIZONTAL DEFLECTION SYST SYSTEM Sweep Range A Sweep B Sweep Accuracy 15 C to 35 C 10 C to 15 C and 35 C to 55 C Sweep Linearity relative to center two displayed divisions POSITION Control Range Normal Displays X Y Displa
33. IS f r den Benutzer Betreiber Dies Ger t darf in Me aufbauten nur betrieben werden wenn die Voraussetzungen des Par 2 Ziff 1 7 1 der Vig 1046 1984 eingehalten werden Gi ER 2246 Operators OPERATORS SAFETY SUMMARY The general safety information in this part of the summary is for both operating and servicing personnel Specific warnings and cautions will be found throughout the manual where they apply and do not appear in this summary Terms in This Manual CAUTION statements identify conditions or practices that could result in damage to the equipment or other property WARNING statements identify conditions or practices that could result in personal injury or loss of life Terms as Marked on Equipment CAUTION indicates a personal injury hazard not immedi ately accessible as one reads the markings or a hazard to property including the equipment itself DANGER indicates a personal injury hazard immediately accessible as one reads the marking Symbols in This Manual A Symbols as Marked on Equipment This symbol indicates where applicable cau tionary or other information is to be found For maximum input voltage see Table 1 2 4 DANGER High voltage amp Protective gound earth terminal A Power Source ATTENTION Refer to manual This product is intended to operate from a power source that will not apply more than 250 voits rms between the supply conductors or
34. RACK MEASMT cursors and turns off the TRACK TRIG LVL and TRACK rh cursors in three levels depending on what is on that can be turned off If a menu is on the first press clears it from the display measurement func tions are turned off with the second press or the first press if no menu is displayed and finally the TRACK TRIG LVL and TRACK rh cursors are canceled with a third press or the first press if no menu is displayed and no measurement functions are active SET MEASUREMENT CHANNEL The menu called up by pressing SET MEAS MT CHAN NEL depends on the measurement type either CH1 CH2 VOLTMETER or ATIME see Table 6 1 An error message of NO MEAS CHANNEL NEEDED is displayed for two seconds if attempting to select a measurement channel when a CURSORS time measurement mode is active Pressing a menu button next to a channel number selects that choice as the source channel for the measure ment For CHi CH2 VOLTMETER measurements the selected source channel need not be displayed and is not automatically turned on when selected It is possible there fore to view a CH 1 display and have the CH 2 voltage measurement value displayed by the readout and vice versa When setting the measurement channel for the l VOLTS l or rh VOLTS i SmartCursors or when set 6 1 Measurement Processes and Applications 2246 Operators Table 6 1 Measurement Signal Source Selection Menu CH1 CH2 ATIME VOLTMETER CH CH1 CH1
35. RACK MEASMT cursor s will be displayed again when a CH1 CH2 VOLTMETER measurement is cail up Setting Trigger Level The trigger level readout supplied by the TRACK TRIG LVL cursor may be used to set a specific trigger level for triggering on a displayed waveform As an example assume the following conditions 1 The signal to be examined is a mix of two different signal levels see Figure 6 17 2 We want to trigger on the larger amplitude signals to make a closer examination of their waveshape and take pulse width and or rise time measurements To set the Trigger LEVEL to the appropriate level with no signal applied or with GND input coupling use the TRACK rh cursor feature The TRACK rh cursor menu choice is reached through the same menu path as the TRACK TRIG LVL cursor The ground cursor provides feedback to the user so that the ground level may be posi tioned without the need for a ground baseline trace 6 20 QUESTION MARK APPEARS WHEN B SWEEP IS NOT RUNS AFTER A TRIGGER LEVEL CURSOR B TRIGGER LEVEL CURSOR Figure 6 16 A and B TRACK TRIG LVL cursors Set the VOLTS DIV control so that the displayed signal will have a good viewing amplitude For the assumed sig nal shown in Figure 6 17 a setting of 1 V div will produce a four to five division display amplitude Position the ground cursor using the VERTICAL POSITION control at about two graticule divisions below the center graticule line For neg
36. RACK MEASMT feature it only turns off the present display of the TRACK MEASMT cursor when it turns off the active measure ment mode The next time a CH1 CH2 VOLTMETER measurement mode is selected the TRACK MEASMT cursor or cursors will again be displayed TRACK TRIG LVL Press to enable or disable the Trigger Level tracking cursor See USING THE TRACK TRIG LEVEL CURSORS in this section for conditions required to display the Trigger Level tracking cursors TRACK GND Press to enable or disable the ground level tracking cursor BACK TO PREVIOUS MENU Selects menu 1 choices MENU OFF Clears the menu from the display 6 4 ATIME MENUS Press the ATIME button to call up the time measure ment choices shown in Figure 6 3 Vertical cursors are displayed for use in setting the time measurement points in A Horizontal MODE In ALT Horizontal MODE the delay measurement is made using either the intensified zones as the measurement points or the alternate B delayed sweeps For B Delayed Horizontal MODE the delayed sweeps only are available for making timing measurement When the Horizontal MODE is either ALT or B the B Trigger MODE is forced to RUNS AFTER if the B Trigger MODE is switched away from RUNS AFTER using the front panel Trigger MODE buttons a selected ATIME measurement will be canceled Pressing LAST MEAS MT will return the B Trigger MODE to RUNS AFTER and restart the last selected ATIME measurement if
37. RS and select the i SEC gt menu choice 7 Use the I OR DELAY control to align the first cur sor to the rising edge at the point it crosses the 10 refer ence graticule line Then use the I OR A control to align the second cursor to the point that the rising edge crosses the 90 graticule line and read the rise time displayed in the top line of the crt readout see Figure 6 13 Phase Measurements Making a phase measurement is done by first setting a reference for the full 360 degree waveform period Use the following procedure as a guide 1 Apply the reference waveform to the CH 1 input connector any channel may be used but CH 1 and CH 2 provide the most signal scaling possibilities Use the standard 10X attenuator probe supplied with the instru ment to make the signal connections as they produce very little signal loading to a circuit under test and produce matched delays For phase measurements external load ing of a circuit and different delays in the signal connection paths will produce incorrect results RISETIME gece ed ae ai T AN ace cee Zee EERE EHRE A BEIN Figure 6 13 Rise time measurement REV APR 1987 rm ee En y i i 3 j wm Boy ae nd En 4 2 Select CH 1 for display using the VERTICAL MODE buttons and set the Input COUPLING for CH 1 and CH 2 to DC AC may be used if the signals to be measured are riding on a de voltage but set both
38. S l cursors The independent cursor is initialized to the PEAK of the input waveform 3 Position the independent cursor using the i or A control to the measurement point on the waveform and read out the dc value of the cursor position shown in Figure 6 10 The l or DELAY control has no effect REV APR 1987 Measurement Processes and Applications 2246 Operators bs 3 Use the I OR DELAY control to position the refer MOVABLE DC VOLTS ence cursor to the point on the waveform to be measured CURSOR from Use the I OR A control to position the independent cursor to the second point of interest Then read the time difference value in the top line of crt readout cee et Pulse Period Measurement This measurement is basically a time difference measurement The i SEC i cursors are positioned to define a full period of the input waveform and the time difference value displayed is the pulse period Use the setup for making time difference measurements as a guideline for making pulse period measurements see Figure 6 11 Einf Frequency Measurement GROUND CURSOR A frequency measurement is made the same as the pulse period measurement the difference being that the l 1 SEC cursors are selected from the CURSORS menu The measurement value displayed with units of fre quency When the exact pulse period is defined by posi tioning the cursors the frequency of the signal is NOTE displayed Use the same front panel
39. SE 250V ZA SLOW TEKTRONIX INC BEAVERTON OREGON U S A B rca 6083 08 Figure 3 6 Rear Panel Connectors and Fuse menu display is cleared The menu displays may be configured to remain on from the CONFIGURE menu see Section 6 When a menu is recalled to make a new selection the label of the active func tion is shown underlined A function is turned off either by pressing the active function menu button a second time or by selecting another menu choice when only one choice may be active If there is no label next to a Menu Select button that button is ignored if pressed Some menus have more than six choices available For menus that are longer than one page press the Menu Select button opposite the menu choice direct ing the user TO the next page for the additional choices The first page of the menu is returned either by pressing the Menu Select button for that menu list a second time or by selecting the menu choice in the second menu page that directs the user BACK TO to the first page Menu Display Control Buttons Control the menu display and call up Measurement selection menus that are displayed on the right side of the crt screen CLEAR DISPLAY Turns off a displayed menu turns off a measurement function and TRACK MEASMT cursors if displayed or turns off the TRACK TRIG LVL and TRACK rh functions in three levels If a menu is on the first press clears it from the display active measuremen
40. TERNAL TRIGGERING The A and the B trigger signals are independently obtainable from a variety of sources When viewing signals that require a trigger source different than one of the displayed signais a free vertical input channel may be used to input the trigger signal The CH 1 and CH 2 verti cal input channels may be used to condition a wide range of signais to produce triggers over the full vertical deflection range from millivolts to hundreds of volts in amplitude The CH 3 and CH 4 vertical input channels have a choice of two attenuation factors either divided by 1 or by 5 without the use of external attenuation and are especially usefui for triggering on and viewing digital signal levels 4 3 Morerod Von E RE B al Eai zw i Section 5 2246 Operators OPERATOR S CHECKS AND ADJUSTMENTS INTRODUCTION If adjustments are required beyond the level of these operator s checks and adjustments refer the instrument to a qualified service person For new equipment checks before proceeding with these instructions refer to Preparation for Use Section 2 of this manual to prepare the instrument for the initial start up before applying power Verify that the POWER switch is OFF out position then plug the power cord into an appropriate ac power source outlet supplying a voltage within the operating range of the instrument s power supply During the performance of these procedures if an improper indica
41. UT COUPLING MODE UNCAL SYMBOLS AC N BW LIMIT CH2 INDICATOR INVERT CH3 VOLT DIV CH4 VOLTS DIV A SEC DIV X10 SEC DIV OR X SEC DIV MODE UNCAL INDICATOR INDICATOR Figure 4 2 2246 Readout display locations The standard 10X probes supplied with this instrument offer a high input impedance that minimizes circuit loading This allows the circuit under test to operate with a minimum of change from the normal unloaded condition Also the subminiature body of these probes has been designed for ease of use when probing circuitry containing close lead spacing The probe itself and the probe accessories should be handled carefully at all times to prevent damage Striking a hard surface or dropping the probe body can cause dam age to both the body and the probe tip Use care to prevent the cable from being crushed or kinked and do not place excessive strain on the cable by pulling it The standard accessory probe is a compensated 10X voltage divider It is a resistive voltage divider for low fre quencies and a capacitive voltage divider for high frequency signal components Inductance introduced by long signal or ground leads may form a series resonant circuit This resonant circuit will affect system bandwidth and will oscillate ring if driven by a signal containing 4 2 significant frequency components at or near its resonant frequency Ringing can then appear on the scope display and distort the
42. al measure ment applications MENU SYSTEM OPERATION The menu system is used to activate the measurement features of the 2246 and modify the ways in which those features operate The control menus comprise the measurement menu call up buttons SET MEAS MT CHANNEL LAST MEAS MT CHi CH2 VOLTMETER CURSORS and ATIME the menu item selection buttons beside the ort the crt menu display and the CLEAR DISPLAY button Pressing one of the measurement menu call up buttons causes a list of menu items to be displayed on the right hand side of the crt beside a group of six menu selection buttons Pressing the menu button next to a menu item on the display selects that function i e to another menu page a measurement selection a measurement source channel or menu off When an measurement mode or measurement source channel in the menu list is selected that label is underlined Normally the menu display turns off after a measure ment function is selected if not configured to remain on and the name and value of a selected measurement func tion appears in the top line of the crt readout However when it is possible to make more that one selection from the menu list or if the menu is configured to remain on the menu will remain displayed for making further choices until either MENU OFF is selected or the CLEAR DISPLAY button is pressed CLEAR DISPLAY Turns off a displayed menu turns off a measurement function and CHI CH2 T
43. ally positioned by the associated vertical channel POSITION control A AND B SEC DIV Switch Selects the horizontal deflection rate sweep speed for both the A Sweep and the B Sweep in a 1 2 5 sequence Calibrated sweep speeds are obtained with the A and B SEC DIV VAR control in the calibrated detent fully clockwise position A SEC DIV The calibrated A Sweep speed is selected only in A Horizontal MODE from 0 5 s per division to 20 ns per division X10 MAG off B SEC DIV The calibrated B Sweep speed is selected either in ALT or B Horizontal MODE from 5 ms per division to 20 ns per division X10 MAG off A and B SEC DIV VAR Control Provides continu ously variable uncalibrated A Sweep and B Sweep speeds to at least 2 5 times slower than the cali brated SEC DIV setting The VAR control extends the slowest A Sweep speed to at least 1 25 sec per division A greater than sign gt will appear before each displayed SEC DIV setting when the VAR control is out of its detent position CURSORS TIME POSITION I OR DELAY Controi Positions both the reference cursor and the delta cursor together when one of the cursor measurement modes is selected volts or time in the A Horizontal MODE positions the reference delay and the deita delay together when in ALT or B Hor izontal MODE with ATIME measurements active The control sets the B Sweep delay time in ALT or B Horizontal Mode in DELAY measurement mode and positions th
44. als non repeating and signals containing many unrelated fre quency components may require more trigger signal condi tioning and or holdoff to obtain the best display 1 Apply the test signal to be measured to either the CH 1 or the CH 2 input connector If using coaxial cable to make the signal connections remember to correctly ter minate them at the input to the 2246 If using the supplied 10X probes no further matching devices are needed The choice of using coaxial cables or a probe to connect the input signal depends on the signal s source Generally for an active circuit under test probes are used signals from test generators usually are connected via terminated coax ial cables 2 Set the front panel controls as follows A INTEN and READOUT For good viewing intensity SCALE ILLUM As needed VERTICAL MODE To display the test signal VERTICAL POSITION Center the display vertically 6 9 Measurement Processes and Applications 2246 Operators Input Channel VOLTS DIV Setting VAR VOLTS DIV To display about 3 to 5 divisions of signal Calibrated fully clockwise in detent input Channel COUPLING DC BW LIMIT OFF button light off CH 2 INVERT OFF button light off Horizontal MODE A X10 MAG Off button light off SEC DIV Suitable sweep speed for the applied signai Start of trace at left graticule edge Set to select the A Trigger control settings button light on TRIGGER MODE
45. and 30 C has had a warmup period of at least 20 minutes and is operating at an ambient tem perature between 10 C and 55 C unless otherwise noted Items listed in the Performance Requirements column are verifiable qualitative or quantitative limits that define the measurement capabilities of the instrument Mechanical Specifications of the 2246 are given in Table 1 2 and Environmental Specifications are given in Table 1 3 RECOMMENDED CALIBRATION SCHEDULE To ensure accurate measurements check the perform ance of this instrument every 2000 hours of operation or if used infrequently once each year Replacement of com ponents in the instrument may also necessitate readjust ment of the affected circuits 1 1 Specification 2246 Operators Table 1 1 Electrical Characteristics Characteristics l Performance Requirements VERTICAL DEFLECTION SYSTEM CH 1 AND CH 2 Deflection Factor Range 2 mV div to 5 V div in 1 2 5 sequence Accuracy includes ADD MODE and CH 2 INVERT 15 to 35 C Within 2 10 C to 15 C and 35 C to 55 C Within 3 Variable Range Increases deflection factor by at least 2 5 1 Frequency Response 3 dB bandwidth 10 C to 35 C DC to 100 MHz at the probe tip 35 C to 55 C DC to 90 MHz at the probe tip AC Coupled Lower 3 dB Point 1X Probe 10 Hz or less 10X Probe 1 Hz or less Step Response 5 division step Rise Time 10 C to 35 C 3 5 ns o
46. asurement mode The menu will be removed if configured to do so and any enabled tracking cursors will be displayed If none are enabled in page 2 of the CURSORS menu none will be displayed kad a EG am GREEN Tisa R MEASUREMENT TRACKING CURSOR PEAK VOLTAGE PEAK AC DC OFFSET GROUND TRACKING CURSOR 6083 21 Figure 6 7 PEAK voltage measurement and tracking cursors NOTE Only a choice of two of the possible three available selections may be displayed on a priority basis TRACK MEASMT has the highest priority followed by TRACK TRIG LVL and TRACK gnd in that order Also the TRACK TRIG LVL and TRACK gnd cursors may only be displayed on the Trigger SOURCE sig nal The TRACK MEASMT cursor may be directed to either CH 1 or CH 2 input signal without regard as to what the trigger signal SOURCE is 2 Adjust the B INTEN and A INTEN controls to pro vide a good viewing contrast of the intensified zone that appears on the A Sweep trace NOTE IF the zone does not appear it may be positioned out of the viewing area but not past the end of the A Sweep trace Turn the I OR DELAY control counterclockwise to move the gate zone closer to the beginning of sweep l 3 Use the OR DELAY control to position the intensified zone to the area of interest on the waveform to be tracked See Figure 6 8 REV APR 1987 Measurement Processes and Applications 2246 Operators 4 The width of the
47. ative going signals two divisions above the center graticule would about center the display and for bipolar signals centering the ground trace is appropriate Zeroing the Trigger LEVEL control may be useful if the cursor is positioned out of the viewing area Simply switch the Input COUPLING of the selected channel to GND and switch the Trigger MODE to AUTO LEVEL Once zeroed set the Trigger MODE to NORM so that the Trigger LEVEL you set will be maintained if AUTO LEVEL is left on the Trigger LEVEL will continue to follow the applied signal ground in this case Use the Trigger LEVEL control to position the trigger level cursor to about 3 V measured from the ground cursor For the assumed signal this level is ample to avoid triggering on the lower amplitude signals in the display For other waveforms the user must deter mine what trigger level is needed to obtain triggering on a specific waveform amplitude Apply the signal to the appropriate input channel con nector and set the Input COUPLING to DC The N pi dc SYMBOL Figure 6 17 Setting a specific Trigger LEVEL waveform display will now appear assuming the A INTEN SITY is set to a viewing level and it will be triggered on the larger amplitude pulses of the signal Once triggering is obtained the A SEC DIV setting may be set to a faster sweep speed to expand the triggering pulse for making any measurements wanted USE OF THE ADD MODE
48. ative peak 6 3 Measurement Processes and Applications 2246 Operators rh VOLTS i Calls up a cursor to mark the ground position of the selected waveform display in either A Horizontal MODE or X Y Horizontal MODE The ground cursor follows the ground level of the source channel waveform as it is positioned vertically TO AUTO TRACKING MENU Selects CURSOR measurement menu 2 choices Cursor Menu 2 All of the tracking cursor selections may be underlined but only two cursors of either type tracking or measure ment may be displayed at a time If TRACK MEASMT is selected and a CH1 CH2 VOLTMETER measurement is active the TRACK rh cursor is not displayed when TRACK TRIG LVL is also active If the MEASUREMENT is turned off the ground tracking cursor will return to the display CLEAR DISPLAY may be used to turn off the MENU MEASUREMENT and TRACK TRIG LVL and TRACK rh cursors in a priory scheme of three levels MENU first MEASUREMENT and TRACK MEASMT cursors second and TRACK TRIG LVL and TRACK rh cursor last The highest level being displayed is turned off each time the CLEAR DISPLAY button is pressed TRACK MEASMT Press to enable or disabie the CH1 CH2 VOLTMETER measurement tracking cursors SmartCursors that attach to the waveform measurement points The state of the TRACK MEASMT feature does not affect the positionable l VOLTS i cursor operation The CLEAR MENU but ton will not turn off the T
49. between either supply conductor and ground A protective ground connection by way of the grounding conductor in the power cord is essential for safe operation Grounding the Product This product is grounded through the grounding conductor of the power cord To avoid electrical shock plug the power cord into a properly wired receptacle before making any connections to the product input or output terminals A protective ground connection by way of the grounding conductor in the power cord is essential for safe operation Danger Arising from Loss of Ground Upon loss of the protective ground connection all accessi ble conductive parts including knobs and controis that may appear to be insulated can render an electric shock Use the Proper Power Cord Use only the power cord and connector specified for your product Use only a power cord that is in good condition For detailed information on power cords and connectors see Figure 2 1 Use the Proper Fuse To avoid fire hazard use only a fuse of the correct type voltage rating and current rating as specified in the parts list for your product Do Not Operate in Explosive Atmospheres To avoid explosion do not operate this instrument in an explosive atmosphere Do Not Remove Covers or Panels To avoid personal injury do not remove the product cov ers or panels Do not operate the instrument without the covers and panels properly installed 2246 Operators 6083 01
50. control but maximum value does not exceed end of the A Sweep REV FEB 1988 gamona Femme Ree ren Germanen pam year eu Fe EEE en tYg eee an Wi I af a ER a ne wd gt BR Hl Ea f I c Specification 2246 Operators Table 1 1 cont Yy Characteristics nanmeteiiee _ Pertormance Requirements Performance Requirements Sensitivity CH 1 through CH 4 AUTO LEVEL NORM AND SINGLE SEQUENCE COUPLING DC NOISE REJECT HF REJECT LF REJECT AC TV LINE TV FIELD AUTO LEVEL Lowest Usable Frequency LEVEL Control Range TRIGGER LEVEL READOUT Accuracy HOLDOFF Control Range REV OCT 1986 A AND B TRIGGER Trigger sensitivity is defined as the minimum peak to peak sine wave trigger signal amplitude required to show the test signal with horizontal jitter of less than 3 0 of one period p p viewed over two seconds 0 35 division from DC to 25 MHz increasing to 1 0 division at 150 MHz 1 4 division from DC to 50 MHz increasing to 2 2 division at 100 MHz 0 5 division or less will not trigger 0 35 division from DC to 50 kHz attenuates signals above the upper 3 dB cutoff frequency of 70 kHz 0 35 division from 100 kHz to 25 MHz increasing to 1 0 division at 150 MHz attenuates signals below the lower 3 dB cutoff fre quency of 50 kHz 0 35 division from 50 Hz to 25 MHz increasing to 1 0 division at 150 MHz attenuates signais below the lower
51. cting the first number from the second or the smaller from the larger ee Using the B delayed traces in ALT Horizontal MODE Fr IN 4 permits the most accurate measurement of time difference h to be made The method described uses the center vertical SBRNERZERE graticule line as a measurement reference point Use the following procedure as a guideline for making delay time measurements 1 Set up the signal to be measured and the front panel controls as indicated in steps 1 and 2 ofthe PEAK Bruns va VOLTAGE MEASUREMENT procedure ANN fe 2 Select an A SEC DIV setting that produces an A VI AN V trace long enough to display both measurement points of 7 N interest on the waveform DAI 3 Switch to ALT Horizontal MODE and advance the N AS A B SEC DIV setting three positions faster than the A BEM u Er SEC DIV setting if possible You may set the BSEC DIV au setting faster than three positions if you wish in which DEZ case the intensified zone on the A trace becomes even more necessary as an aid in identifying the measurement points 4 Set the input channel VOLTS DIV setting to produce a two to three division vertical display Position the display in the upper half of the graticule area above the center horizontal graticule line Tey arme NOTE if more than one vertical channel is being displayed a more viewable display is obtained by reducing the vertical display amplitude to about one division
52. ctors and indicators 2246 Operators H SEC 4 H 4 SEC 4 k VOLTS 4 Ah VOLTS 4 H PHASE 4 TO AUTO TRACKING MENU TRACK MEASMT TRACK TRIG LVL TRACK BACK TO PREVIOUS MENU MENU OFF Figure 3 9 CURSOR Measurement Menus make measurements on the CH 3 or CH 4 waveforms with less accuracy than possible on the CH 1 or CH 2 waveforms by setting the VOLTS DIV setting of the measurement source channel to the same VOLTS DIV setting as the channel the signal to be measured is on For example if the signal to be measured is on CH 4 at 0 5 VOLTS DIV set the measurement source to CH 1 and CH 1 VOLTS DIV to 0 5 V ATIME Button Calis up the menu used to select the type of timing measurement to be made Menu choices are listed on the right side of the screen A selected ATIME measurement mode is under scored when the menu is displayed Only one Ground Cursor Left dimensioned cursor E jada a BE EEE Er BEE BEE ee ee Ser SEE Be Er Se SE Right dimensioned cursor Figure 3 10 Cursor identifiers active measurement at a time is allowed Upon making a selection the menu is removed and the name of the selected measurement type and readout of the measurement value are displayed at the top of the screen Menu selections for ATIME measurements are shown in Figure 3 11 In the A Horizontal MODE cursors are used to make the time measurements in ALT or B Hor izontal MODE the timing measurements are made usin
53. delay time readout DELAY is displayed when the Horizontal MODE is ALT or B and no menu selectable measurement mode is active Push CLEAR DISPLAY to turn off menu selected measurements Delay time is set using the l OR DELAY control In RUNS AFTER B Trigger MODE the delay time from the start of the A Sweep to the start of the B Sweep is set and the top line of the readout displays the time delay between the start of the A sweep and the start of the B Sweep For triggered B Sweep modes AUTO LEVEL NORM and TV LINE the delay time to the arming of the B trigger is set not the displayed delay and a question mark is displayed in front of the delay time readout value In ALT Horizontal MODE with the A and B SEC DIV settings set to the same sweep speed there is no Alter nate B trace and the length of the intensified zone appearing on the A Sweep trace is 1 100 of the SEC DIV setting The position of the dot on the A trace indicates the position of the DELAY setting The dot may be use to 6 15 Measurement Processes and Applications 2246 Operators The small dot size is also a convenient marker for mak ing quick but not the most accurate time measurements Simply position the dot to the first point of interest to be measured from and note the delay time setting shown in 4 the crt readout Then position the dot to the second point of interest and again note the delay time setting The time difference is calculated by subtra
54. dvantage of the 0 2 division minor grati cule markings on the center graticule lines Also position one of the measurement points of the waveform as pre cisely as possible on one of the major graticule marks to be used as a measurement reference point CRT READOUTS The ert readout display is the user s guide to how the instrument controls are set up No physical markings are on the rotating switches and contro knobs to indicate the control setting A key to the location and type of readout information displayed is illustrated in Figure 4 2 GROUNDING The most reliable signal measurements are made when the 2246 and the unit under test are connected by a com mon reference ground lead in addition to the single lead or probe The ground lead of the probe provides the best grounding method for signal interconnection and ensures the maximum amount of signal lead shielding in the probe cable A separate ground lead can also be connected from the unit under test to the oscilloscope ground jack on the front panel using a banana tip connector SIGNAL CONNECTIONS Probes Generally probes offer the most convenient means of connecting an input signal to the instrument and are Shielded to prevent pickup of electromagnetic interference 4 1 Operating Information 2246 Operators ERROR MESSAGES CH2 INPUT COUPLING CH2 VOLTS DIV CH1 INPUT COUPLING CH1 VOLTS DIV CH1 UNCAL a INDICATOR ig ADD CH2 INP
55. e value readout of any of the CH1 CH2 VOLTME TER measurements AC Capacitively couples the input signal to the vertical attenuator when the AC button light is on Turning AC coupling on turns DC coupling off With AC coupling the de component of the input signal is blocked The lower 3 dB frequency limit is 10 Hz or less when using either a 1X probe or properly terminated coaxial cable it is 1Hz or less using a compensated 10X probe With AC Coupling selected an AC symbol appears on the right side of the associated VOLTS DIV readout display Selecting the DC measurement of the CH1 CH2 VOLTMETER choices when AC Input Coupling is in effect for the measurement source channel causes the 3 3 Controls Connectors and Indicators 2246 Operators error message CH 1 or CH 2 SELECT DC COUPLING to appear DC Couples de and all frequency components of the input signal to the vertical attenuator when the DC button light is on Turning on DC coupling turns off AC coupling With DC Coupling selected a DC symbol appears on the right side of the associated VOLTS DIV readout display Input resistance is 1 MQ to ground See Figure 3 3 for items 18 through 23 3 4 CH 1 OR X and CH 2 Input Connectors Connect external signals to the inputs of Channel 1 and Channel 2 vertical attenuators The input connectors are BNC type with an outer contact ring for the probe code recognization circuit in X Y m
56. e intensified zone for GATED CH1 CH2 VOLTMETER measurements CURSORS TIME POSITION OR A Control Positions the delta cursor when one of the cursor measurement modes is selected sets the B Sweep delta delay in ALT or B Horizontal Mode when the REV APR 1987 oy RT est l l ed meod a 33 A B SELECT Button Directs the MODE SOURCE Pe use ATIME measurement mode is active Sets the width of the intensified zone for GATED CH1 CH2 VOLTMETER measurements NOTE The delta cursor may be positioned to the end of the A trace however the delta delay time has a range of only ten times the A SEC DIV setting 10 divi sions When maximum delta delay has been reached increasing the main delay time reduces the spacing between the two delays and they do not track together delta delay cannot be increased G1 UNCAL Indicates that the A AND B SEC DIV VAR control is out of the calibrated detent position when lighted TRACE SEP Control Positions the B Sweep trace vertically with respect to the A Sweep trace when ALT Horizontal MODE is selected TRIGGER See Figure 3 5 for items 33 through 39 CPLG SLOPE and LEVEL controls and Trigger LED indicators TRIG D and READY to either the A Trigger system or the B Trigger system The A B SELECT button light is on for the A Trigger and off for the B Trigger When switching Horizontal MODES the A B SELECT choice is
57. ependent cursor Then simply read the measurement value displayed in the top line of the readout 4 To make voltage difference measurements between any other locations on the waveform simply move the l cursor to the new point of interest then position the independent I cursor to second point on the waveform and read the voltage difference DC VOLTAGE Plus and minus dc voltage measure ments using ground as a reference are made using the rh VOLTS i cursors The ground tracking cursor is fixed at the de ground level of the applied signal and the 6 12 PK PK VOLTAGE sd gesal SS A ae oD MEANT ae FAUNAN TIA SVS enim aaa BEE EN EEE rota Figure 6 9 Voltage difference measurement using cursors independent cursor above or below ground as necessary to measure the instantaneous dc voltage at the cursor position Use the following procedure steps to set up to measure ground referenced dc voltages 1 Set up the signal to be measured and the front panel controls as indicated in steps 1 and 2 of the PEAK VOLTAGE MEASUREMENT procedure NOTE An important point to remember here is to have the Input COUPLING set to DC A question mark will appear in front of the measurement value readout if the coupling is not DC because any dc offset present with the applied waveform will be removed when AC Input COUPLING is used 2 Press the CURSORS button to display the measure ment selection menu and select the rh VOLT
58. er We hereby certify that the 2246 PORTABLE OSCILLOSCOPE AND ALL INSTALLED OPTIONS complies with the RF Interference Suppression requirements of Amtsbl Vfg 1046 1984 The German Postal Service was notified that the equipment is being marketed The German Postal Service has the right to re test the series and to verify that it complies TEKTRONIX Bescheinigung des Herstellers Importeurs Hiermit wird bescheinigt da der die das 2246 PORTABLE OSCILLOSCOPE AND ALL INSTALLED OPTIONS in bereinstimmung mit den Bestimmungen der Amtsblatt Verfug ng 1046 1984 funkentst rt ist Der Deutschen Bundespost wurde das Inverkehrbringen dieses Ger tes angezeigt und die Berechtigung zur berpruf ng der Serie auf Einhalten der Bestimmungen einger umt TEKTRONIX NOTICE to the user operator The German Postal Service requires that Systems assembled by the operator user of this instrument must also comply with Postal Regulation Vig 1046 1984 Par 2 Sect 1 HINWEIS f r den Benutzer Betreiber Die vom Betreiber zusammengestelite Anlage innerhalb derer dies Ger t eingesetzt wird mu ebenfalls den Voraussetzungen nach Par 2 Ziff 1 der Vfg 1046 1984 genugen NOTICE to the user operator The German Postal Service requires that this equipment when used in a test setup may only be operated if the requirements of Postal Regulation Vig 1046 1984 Par 2 Sect 1 7 1 are complied with HINWE
59. f CH2 is the desired default measurement source channel 6 2 Voltmeter Measurements Page 1 DC Press to measure the average DC level of the measurement channel waveform PEAK Measures the most positive screen relative voltage in the applied waveform PEAK Measures the most negative screen relative voltage in the applied waveform PK PK Measures the peak to peak voltage of the applied waveform SELF CAL Self characterizes the vertical system SELF CAL may be performed at any time Suggested times are after a warmup period whenever the ambient operating temperature changes by 15 C and just prior to making any voltmeter measurements requiring the best possible accuracy TO GATED MEASMT MENU Selects the gated measurement menu Voltmeter Measurements Page 2 GATED Measurements The oscilloscope must be properly triggered for gated measurements If there is no trigger signal in NORM Trigger MODE the message LO REP RATE STILL TRYING will be displayed If there is no trigger signal in AUTO LEVEL or AUTO Trigger MODE the readout value will be unstable and meaningless GATED PEAK Press to measure the most positive screen relative voltage in the gated intensified portion of the waveform REV FEB 1988 Mer genen perm eam ee HA EE PRATT EV PETAR TAA VOLTMETER BC PEAK PEAK PK PK SELF CAL TO GATED MEASMT MENU VOLTS PG 2 PEAK PEAK PK PK
60. for type lil class 3 instruments Non operating and operating at 95 0 to 2 relative humid ity Operating at 30 C and 55 C for all modes of operation Non operating at 30 C to 60 C Radiated and Conducted Emission Required per Meets Category B VDE 0871 Electrostatic Discharge Conforms to Tektronix Standard 062 2862 00 15 minutes along each of 3 major axis at a total displacement of 0 025 inch p p 4 g at 55 Hz with frequency varied from 10 Hz to 55 Hz in 1 minute sweeps Hold for 10 minutes at 55 Hz in each of the three major axis All major resonances must be above 55 Hz Vibration operating mann Bench Handling Test Four inch drop per Tektronix standard 062 2858 00 Shock Operating and Non operating 30 g haif sine 11 ms duration 3 shocks per axis each direction for a total of 18 shocks i Transportation Packaged Vibration Test Meets the limits of Tektronix Standard 062 2858 00 Package Drop Test Meets the limits of Tektronix Standard 062 2858 00 REV APR 1987 1 11 Specification 2246 Operators 5 86 6 35 149 e4 el 156 11 82 12 90 300 328 12 60 Dimensions are in inches mm Figure 1 1 Dimensional drawing aor es me me ea m m me ores Wand be PER Section 2 2246 Operators PREPARATION FOR USE SAFETY This section telis how to prepare for and to proceed with the initial start up of the TEKTRONIX 2246 Oscilloscope Refer to the Operato
61. g either the intensified zones that appear in the A Sweep trace in ALT Horizontal MODE or the B delayed waveforms in either ALT rene ET a pary Era Ao NEAT EAA TSN IN PN Re DENN t acd rer warmen ll ud nd dd und or B Horizontal MODE The I OR DELAY control positions both cursors or delay times reference and delta together and the I OR A control posi tions the independent delta cursor or delay when ATIME measurements are selected When selecting l PHASE i measurement a second menu is displayed to permit the user to set the 360 degree phase measurement refer ence The two choices displayed are l PHASE l and I SET 360 I if the current reference setting is correct select l PHASE i to continue with the phase measure ment To set a new reference press I SET 360 and position the cursors to the new refer ence value using the lk OR DELAY and AOR A control knobs After setting the new reference press l PHASE to continue the phase measurement REV APR 1987 Controls Connectors and Indicators 2246 Operators Fe SEC 4 F 1 SEC 4 H PHASE 4 SELF CAL Figure 3 11 ATIME Menu Selections 3 15 Las Dapereorned Section 4 2246 Operators OPERATING INFORMATION GRATICULE The graticule is internally marked on the faceplate of the crt to eliminate parallax viewing error and to enable accurate measurements see Figure 4 1 The graticule is marked w
62. gated zone is controlled by the i OR A control Adjust the width to define the gated mea surement zone 5 The voltage value that appears in the readout is the PEAK voltage that occurs within the zone CURSOR MEASUREMENTS Time and voltage measurements may be made using cursors to identify the measurement points on the waveform Time measurement cursors may be used on any of the input waveforms only in the A Horizontal MODE The units of the time cursors may be selected to provide some automatic calculations for the user The units of the l SEC I cursors are time s ms us and ns the I 1 SEC cursors have units of frequency Hz kHz and MHz and the l PHASE i cursor units are in degrees and scaled to a 360 degree reference set by the user The time cursors that appear in the CURSORS measurement mode and the time cursors that appear in the ATIME measurement mode in the A Horizontal MODE are exactly the same Voltage cursors are attached to a measurement chan nel either CH 1 or CH 2 to obtain their scaling Voltage measurements using cursors may be done on the CH 3 the CH 4 or the ADD waveform by setting the VOLTS DIV setting of the selected measurement channel to the same scale factor as the signal to be measured However the GATED PEAK VOLTAGE ZONE IN GATED ZONE rt ooreo erfor pagu Figure 6 8 Gated voltage measurement Measurement Processes and Applications 2246 Operators measurement accuracy o
63. he absence of a trigger signal no B Sweep trace occurs TV LINE FROM A SOURCE Starts the B Sweep at the beginning of a the video signal line received after the delay time has been met SLOPE polarity must match the composite sync polarity same as A Trigger SLOPE to obtain correct triggering on the horizontai sync pulse SOURCE Up Arrow and Down Arrow Buttons and Indicators Select the trigger source for either the A or the B Trigger system and indicate the selected source as directed by the A B SELECT button The Up Down SOURCE buttons are used to select the trigger source and the Trigger SOURCE front panel lights indicate the selected trigger signal source for the trigger system selected by the A B SELECT button VERT Selects the trigger signal from the displayed waveforms The selection of the trigger signal source is deter mined by the TRIGGER MODE and VERTICAL MODE switch settings With VERT selected one or more of the SOURCE front panel lights will be on to indicate the trigger signal source See Table 3 2 for VERT Trigger SOURCE selections Table 3 2 VERT Trigger SOURCE Trigger ADD Trigger and Mode SOURCE Vertical Selected Modes AUTO On Algebraic sum of CH 1 and LEVEL Ch 2 input signals or CHOP Off Lowest numbered vertical on channel displayed NON On Alternates between AUTO or displayed vertical channels LEVEL Off in the following order and CH 1 CH 2 CH 3 CH 4 ALT and ADD 3 9
64. in amplitude Then use the Vertical POSITION control and TRACE SEP controls to organize the displayed traces in an order that permits the traces to be identified Up to ten traces may be displayed at a time however extra channel traces not involved in making a measurement should be turned off to elim inate possible confusion Figure 6 14 Making a phase difference measurement set the delay time to a point of interest on the displayed 5 Use the TRACE SEP control to position the alter waveform for expansion using the faster B Sweep speeds nate B delayed trace in the lower half of the graticule area 6 16 i 1 Leb A N N or directly below the A trace display if more than one channel is being displayed 6 Position the intensified zone to the first measure ment point in the waveform using the I OR DELAY con trol The I OR A control has no effect 7 Align the measurement point as displayed by the B delayed trace with the center vertical graticule line The center line then becomes the measurement reference point for making the time difference measurement 8 Note the delay time setting in the upper line of crt readout 9 Now position the intensified zone to the second measurement point and again align the point displayed on the B delayed trace with the center horizontal graticule line 10 Note the second delay time setting Subtract the first setting from the second setting to determi
65. in Figure 3 8 ff the Horizontal Mode is changed to a mode that cannot be used for the selected measurement the measurement will be canceled and no mes Sages to that effect will be displayed See Section 6 for compatible modes GATED VOLTMETER measurements are made within the gated intensified region on the displayed waveform The position of the gated zone is set using the l OR DELAY control and the width is set using the I OR A position con trol Gated measurements are not allowed in SGL SEQ Trigger MODE and any active gated meas urements will be canceled if SGL SEQ Trigger MODE is selected If a gated measurement is Selected after switching to SGL SEQ Trigger MODE the message NOT ALLOWED IN SSEQ will be visible for two seconds if a trigger occurs CURSORS Calls up the Page 1 menus used to select a positionable cursor measurement mode Page 2 menus are used to enable the auto tracking SmartCursors that may be displayed see Figure 3 9 Only two cursors of any type tracking or posi tionable may be displayed at the same time Which enabled cursors are displayed is based on a prescribed priority system with positionable cursors and measurement tracking cursors taking priority over the trigger level and ground tracking cursors Pressing CLEAR DISPLAY turns off the TRACK TRIG LVL and TRACK rh functions and removes the TRACK MEASUREMENT cursors from the waveform display see the CLEAR DISPLAY description for the
66. instrument damage from overheated com ponents adequate internal airflow must be maintained Plug Line Reference Option Configuration Usage Voltage Standards Number DRS ana Gee ee ee re North ANS C73 11 NEMA 5 15 P IEC 83 American 420V Universal Euro 240V CEE 7 ILIV VN IEC 83 240V BS 1363 o Australian RAOV AS C112 TOA u American ZA0V 240V A4 15A Switzerland zer 220V Abbreviations ANSI American National Standards Institute AS Standards Association of Australia BS British Standards institution CEE internationat Commission on Rules for the Approval of Electrical Equipment IEC International Electrotechnical Commission NEMA National Electrical Manufacturer s Association SEV Schweizevischer Elektrotechischer Verein ANS C73 20 NEMA 6 15 P IEC 83 2931 21 6083 35 Figure 2 1 Optional power cords 2 1 Preparation for Use 2246 Operators Before turning on the power first verify that ventilation holes on the bottom and sides of the cabinet are free of any obstruction to airflow START UP On the initial power up of the instrument characteriza tions of the vertical and horizontal systems to calibrate portions of the measurement system are done After the initial 20 minute warmup period the seif characterization procedure is done automatically to adjust the gains and offsets
67. isplay definition G TRACE ROTATION Control Aligns the ert trace with the horizontal graticule lines 0 e 000000 30 e jo T el o 9 o o Dell Del De Ch 6083 03 Figure 3 1 CRT Power and Display controis REV OCT 1986 3 1 Controls Connectors and Indicators 2246 Operators READOUT Control Adjusts brightness of the crt readout display Brightness is increased when the control is rotated clockwise Full counterclockwise rotation of the READOUT control turns off the readout circuitry operation SCALE ILLUM Control Adjusts the light level of the graticule illumination NOTE Maximum life of the graticule illumination lamps is gained by setting the SCALE ILLUM control for the minimum intensity needed for viewing Turning the scale illumination lamps down or off when not needed extends the life many times over using max imum intensity O BEAM FIND Button Restricts the vertical and hor izontal display size to within the graticule area and unblanks the crt to aid the user in locating off screen or overscanned displays CRT Displays the waveform and readout displays in an 80 mm vertical by 100 mm horizontal graticule area Internal graticule lines eliminate parallax viewing error between the trace and graticule lines 0 10 90 and 100 points are marked at the left edge of the graticule as a convenience to the user for making rise and fall time measurements V
68. itally displayed measurement value TRACK TRIG LEVEL Position Accuracy Cursor position 0 05 vertical division on waveform versus digitally displayed trigger level value TRACK GROUND Pasition Accuracy Cursor position 0 05 vertical division on waveform versus baseline displayed with grounded input DELTA TIME FUNCTIONS DELTA TIME Accuracy 0 5 of reading 1 0 of one division of the A Sweep Delay Accuracy A Sweep Trigger Point to 0 5 of reading 5 of one division of the A Sweep Start of B Sweep 25 ns 1 7 Specification 2246 Operators Table 1 1 cont Characteristics Performance Requirements Deflection Factors Accuracy Y Axis 15 C to 35 C 10 C to 15 C 35 C to 55 C X Axis 15 C to 35 C 10 C to 15 C 35 C to 55 C Horizontal X Axis 3 dB Bandwidth Phase Match DC Coupled Active Region Lower Threshold intensity decreases above this voltage Signai Required to Modulate an A or B Trace k Max Input Voltage N input Loading Overshoot rising and falling edge Output Voltage on CALIBRATOR Jack Repetition Rate Data Retention Time X Y OPERATION Same as Vertical deflection system with the VOLTS DIV variable controls in calibrated detent position Within 2 Within 3 Within 3 Within 4 3 MHz or more 3 degrees from DC to 50 kHz EXTERNAL Z AXIS INPUT 1 8 volts or fess 3 8 volts or less at maximum intensity E
69. ith eight vertical and ten horizontal major divi sions Major divisions are further divided into five subdivi sions of 0 2 division each marked along the center vertical and horizontal graticule lines Percentage marks for rise time and fall time measurements are located on the left side of the graticule The vertical deflection factors and herizontal timing are calibrated to the graticule so that accurate measurements may be made directly from the ert The waveform displays are calibrated to the crt grati cule markings for making quick and very accurate esti 1ST OR LEFT VERTICAL GRATICULE 11TH OR RIGHT VERTICAL GRATICULE gt X CENTER HORIZONTAL GRATICULE LINE RISE AND FALL TIME MEASUREMENT PERCENTAGE MARKERS CENTER VERTICAL GRATICULE LINE 4207 03 Figure 4 1 Graticule measurement markings TEE Cae NIC SEART STE DA STEE ERA LS GBR TREY age SEO SB WN EN SE ae mates of waveform parameters Voltage measurements are done by counting the vertical graticule divisions and partial divisions occupied by the portion of the display being measured and then multiplying by the VOLTS DIV setting Time measurements using the graticule markings are done in a similar manner Count the number of hor izontal graticule divisions and partial divisions occupied by the portion of the waveform being measured and multiply by the SEC DIV setting To improve the accuracy of the estimate position the display to take a
70. itude of the trigger source signal MODE Buttons Up Arrow and Down Arrow and Indicators Select and indicate the operating mode of the A and B trigger systerns The Up Down MODE buttons are used to select the trigger system operating mode from the choices of AUTO LEVEL AUTO NORM TV LINE TV FIELD and SGL SEQ for the A Trigger system and AUTO LEVEL RUNS AFTER NORM TV LINE FROM A SOURCE for the B Trigger system as directed by the A B SELECT button The TRIGGER MODE front panel lights indicate the selected mode of operation for the A and the B trigger system A TRIGGER MODES AUTO LEVEL Automatically sets the range of the Trigger LEVEL control to the peak to peak limits of the signal selected as the A Trigger source if that signals amplitude and repetition rate are adequate This mode is very useful for quickly locating the Trigger LEVEL setting for stable triggering The A Sweep free runs if the trigger source signal amplitude is too low or if the repetition rate of the applied signal is too slow An amplitude change of the triggering signal does not cause a reacquisi tion of the peak to peak signal limits unless triggering is lost at the set level See VERT Trigger MODE for related information regarding the Trigger Signal SOURCE selection The signal trigger level is reacquired in the follow ing conditions whenever triggering is lost when the TRIGGER LEVEL control is rotated to either end stop and if the AUTO LEVEL
71. lect and indicate the operating mode of the horizontal deflection system The Up Down MODE buttons are used to select the desired mode of operation the Horizontal MODE indicator lights show the selected horizontal REV OCT 1986 Controls Connectors and Indicators 2246 Operators deflection mode Not all Menu Measurement modes are compatible with all horizontal deflection modes See Section 6 for Menu Measurement operation A Horizontal deflection occurs at a sweep speed determined by the A SEC DIV switch set ting displayed in the crt readout The A B SELECT setting initializes to the A Trigger when ever the A MODE is selected ALT Alternates between the A Sweep with an intensified zone and the B Delayed Sweep Both the A and the B SEC DIV switch settings are displayed in the crt readout The A B SELECT setting initializes to the B Trigger whenever ALT MODE is selected The B SEC DIV switch setting is selectable in ALT Mode but it cannot be set slower than the A SEC DIV switch setting Attempting to do so will switch both the A and the B SEC DIV switch set tings to a slower sweep speed A faster A SEC DIV setting must be set by the A and B SEC DIV switch in the A Horizontal MODE before switching to ALT MODE The B Sweep speed and the length of the intensified zone are both determined by the B SEC DIV switch setting When the A SEC DIV and the B SEC DIV are both set to the same sweep speed an intensified zone 1 100 of
72. line frequency component to the CH 1 input connector 3 Apply a line frequency signal to the CH 2 input con nector To maximize cancellation the signal applied to the 6 21 Measuremen rrocesses and APPICAUOTIST72 230 VPRETALUTS CH 2 input must be in phase with the frequency com ponent to be canceled from the CH 1 signal 4 Turn on CH 1 and CH 2 VERTICAL MODE 5 Set both VOLTS DIV switches to produce displays of about four to five divisions in amplitude 6 Adjust the CH 2 VOLTS DIV switch and VAR con trol so that the CH 2 display is about the same amplitude as the component to be canceled in the CH 1 waveform see Figure 6 18A 7 Select both ADD and CH 2 INVERT Turn off the CH 1 and CH 2 displays and slightly readjust the CH 2 VOLTS DIV VAR control for maximum cancellation of the line frequency component see Figure 6 188 8 The SEC DIV setting may be set to a faster sweep speed to expand the waveform and the display amplitude may be increased by advancing both VOLTS DIV switches and readjusting the VOLTS DIV VAR controls as neces sary to maintain cancellation of the undesired signal component 6 22 tat an PAGERS ESSE E OEE LONE NMOL LO BTL LO EET SE eA ee CH 1 SIGNAL WITH UNWANTED LINE FREQUENCY COMPONENT CH 2 SIGNAL FROM LINE FREQUENCY SOURCE SIGNAL WITH LINE FREQUENCY COMPONENT CANCELED OUT Figure 6 18 8 RESULTANT SIGNAL 3832 15 Eliminating common mode signals ne
73. ls in predefined settings as shipped from the factory SS ae a Ta A Ml Measurement Processes and Applications 2246 Operators MAKING MEASUREMENTS The TEKTRONIX 2246 Oscilloscope provides an accu rate and flexible measurement system After becoming familiar with the controls indicators menus and capabili ties of the instrument an operator can develop convenient methods for making special measurements required by his or her own applications The measurements given in this subsection are examples of typical applications that may assist in developing efficient techniques for your specific measurements A brief description of how the graticule markings are used in making measurements is given in Section 4 of this manual CH1 CH2 VOLTMETER MEASUREMENTS The CH1 CH2 VOLTMETER measurements are con tinuous measurement of the DC PEAK PEAK or PK PK values of an applied signal The readout of the measurement value is given in the crt readout Measure ment tracking and or ground tracking cursors may be displayed to give the user instant feedback about where on the applied signal the measurement is being made and the location of ground level GATED modes of PEAK PEAK and PK PK measurements may be used to define the area of the measurement on the displayed waveform The position and width of the gated region is displayed as an intensified zone on the A trace of the waveform display Position of the gated region on
74. mode is 3 7 Controls Connectors and Indicators 2246 Operators Tektronix 2246 Figure 3 5 Trigger Controls and indicators reselected The trigger selected by the A B SELECT button is the trigger signal that is reac quired except when triggering is lost In that case reacquiring the A Trigger has priority over the B Trigger The trigger level remains as set when switching to AUTO or NORM TRIGGER MODE until the TRIGGER LEVEL control is rotated AUTO Triggers as in NORM Trigger MODE when an adequate trigger signal is applied The A Sweep begins free running for an auto baseline in the absence of a triggering signal or when the repetition rate of the trigger signal is too low see Table 3 1 for critical triggering inter vals The set triggering level changes only when the TRIGGER LEVEL control is adjusted to a new level setting NORM Initiates the A Sweep when an adequate trigger signal is applied In the absence of a trigger signal a sweep is not generated no base line trace is displayed TV LINE Starts the A Sweep at the beginning of a video signal line SLOPE polarity must match Table 3 1 Auto Triggering Intervals SEC DIV Critical Trigger Setting Interval 5 ms div and faster 20 ms 10 ms div 40 ms 20 ms div 160 ms 50 ms div and slower 400 ms the composite sync polarity to obtain TV LINE triggering on the horizontal sync pulse TV FIEL
75. n A SEC DIV setting that produces two to five repetitions or cycles of the signal across the graticule area NOTE When viewing multiple traces it is best to limit the vertical amplitude to about two divisions so that good trace separation may be obtained in the display 3 Switch the Horizontal MODE to ALT Advance the SEC DIV setting at least one position to obtain a faster B SEC DIV setting This activates the B Sweep and expands the intensified portion of the A Sweep trace Yy 4 Press the ATIME button then select the l SEC I menu choice This produces two intensified zones on the A Sweep trace and two alternate B Delay Sweeps Use the TRACE SEP and VERTICAL POSITION controis to position the B Delay Sweeps vertically in the graticule area for ease of viewing the separate traces 5 Use the SET MEAS MT CHANNEL menu choices to seiect the desired channels to make the time measure ments on NOTE When making delay measurements between two different signals for time or phase difference the SET MEASMT CHANNEL choices must be set to the correct measurement source channel to obtain the desired measurement results BOTH delays must be set to the same channel source for making period pulse width or rise time and fall time mea surements If only a single channel is selected for display both delays will default to that channel If a channel is selected as a measurement source it will be turned on if not already on but it
76. n the CH 3 or CH 4 Input signals will be less accurate than available on the CH 1 or CH 2 input signals Volts cursors are also available for making measurements in the both the A Horizontal MODE and the X Y Horizontal MODE Voltage Measurements Using Cursors VOLTAGE DIFFERENCE Use the following procedure steps as a guideline in making voltage difference measure ments using the positionable cursors t Set up the signal to be measured and the front panel controls as indicated in steps 1 and 2 of the PEAK VOLTAGE MEASUREMENT procedure 2 Press the CURSORS button to display the measure ment selection menu and select the l VOLTS I cursors The Voltage cursors are initialized to the peak to peak lev els of the lowest numbered displayed channel of either CH 1 or CH 2 see Figure 6 9 NOTE Voltage cursors are initialized to levels seen by the peak detector circuitry Noise and other signals rid ing on the signal to be measured will cause a slight displacement of the cursors from the displayed waveform peaks and above 50 MHz the bandwidth rolloff of the trigger circuit will affect the initial cursor positions on the waveform 3 For a peak to peak voltage measurement slightly reposition the cursors as necessary to precisely align them with the peak amplitudes of the waveform and the work is done The l OR DELAY control positions both cursors together keeping the original spacing and the 1 OR A control positions the ind
77. ne the time difference ATIME DELAY MEASUREMENT In the A Horizontal MODE the time cursors that appear when the measurement mode is enabled are exactly the same as those that are seen for the CURSORS measure ment mode and the measurement choices are the same Refer to CURSORS MEASUREMENT for their use When in ALT or B Horizontal MODE the ATIME measurement mode provides two intensified zones on the A Intensified trace There are also two associated B delayed traces matching the intensified zones A direct readout of the delay difference between the two zones is displayed in the top line of crt readout Use the following procedure steps as a guideline for making ATIME delay time measure ments 1 Apply the signals that measurements are to be made on to the vertical input connectors Turn on the VERTICAL MODEs needed to display the signals NOTE Probes are the most convenient for in circuit testing and coaxial cables are the most convenient when using signal generators as the source of the test sig nals Use correct terminations to match the output impedance of any signal generator used The CH 1 and CH 2 vertical channels provide the widest range of signal conditioning and the CH 3 and CH 4 verti cal channels are most useful for digital signal levels REV APR 1987 Measurement Processes and Applications 2246 Operators 2 Use a VOLTS DIV setting that produces a usable vertical display amplitude for viewing ease use a
78. ng the Menu Display Con CONF IGURE SCOPE OPERATING FEATURE TO CHOOSE YES NO RUNNING 6083 19 Figure 6 5 Configure Menu Measurement Processes and Applications 2246 Operators trol buttons Selecting NO in the CONFIGURE menu retains the normal menu removal operation A choice of YES in the CONFIGURE menu causes the measurement menus to remain displayed during the measurement after a selection has been made The feature may be used to permit quick selection of a series of measurements on a waveform or to switch measure ment channels back and forth without recalling the active menu each time Operating in this manner once a user is finished with a particular menu it may be removed by sim ply pressing the CLEAR DISPLAY button once After the YES NO choice the next configuration choice is displayed is made KEEP READOUT ON Normal operation for this operat ing mode is decided in favor of possible camera use to record the resulting single sequence display The readout is displayed briefly after the sequence has compieted to get it on film and then removed to prevent overexposure That is the NO choice The YES choice for the feature permits the user to view any of the measurements that continue to be made during SGL SEQ trigger mode even if no waveform is being displayed The front panel control settings may also be made in SGL SEQ without the need to change the Trigger MODE from SGL SEG to view the readouts as
79. no other measurement type has been selected first i SEC I Press to measure the equivalent time difference between the two vertical cursors displayed in the A Horizontal MODE or the two time delays in ALT or B Horizontal mode The position of the both cursors or both delays is controlled by the l or DELAY control the position of the A cursor or the A delay is controlled by the I or A control The measured time difference between the two cursors or delays is displayed in the ert readout if the Horizontal MODE is X Y pressing the l SEC l button causes the message USE A ALT OR B H SEC 4 r 1 SEC 4 k PHASE 4 SELF CAL Figure 6 3 ATIME Measurement Menus j rc Ken cr Sevres F g Terms Li S ER Pe Fal Be 3 MODE to be displayed for two seconds Changing the Horizontal MODE to X Y after I SEC i has been activated will cancei the measurement with no message l 1 SEC i Measures the time difference in frequency units hertz between the cursor positions in A Horizon tal MODE or between the delay time setting and the deita delay time setting in either ALT or B Horizontal MODE Measurement points are the left ends of the two intensified zones in ALT Horizontal MODE i PHASE I Calls up a lower level menu for phase measurement operation l PHASE I Cursor positioning or delay and delta time setting is identical to the l SEC mode The value displayed fo
80. ns the primary power fuse Power Cord Receptacle Connects the ac power source to the instrument power supply The power cord safety ground connection is con nected to the exposed metal parts of the instrument The power cord must be connected to a properly grounded source for electrical shock protection MENU CONTROLS See Figure 3 7 for items 43 and 44 See Section 6 Measurement Processes for detailed use of the menus for making cursor measurements 43 Menu Select Buttons Used to make a menu selec tion from the list that is displayed on the right side of the crt A menu driven function is activated by pressing the Menu Select button next to the menu label and the ey Controls Connectors and Indicators 2246 Operators CAUTION TO AVOID ELECTRIC SHOCK THE POWER CORD PROTECTIVE GROUNDING CONDUCTOR MUST BE CONNECTED TO GROUND DO NOT REMOVE COVERS REFER SERVICING TO QUALIFIED PERSONNEL DISCONNECT INPUT POWER BEFORE REPLACING FUSE FOR CONTINUED FIRE PROTECTION REPLACE ONLY WITH SPECIFIED TYPE AND RATED FUSE ee Lu LH Tod TG REMOVE POWER CORD DISCONNECT PLUG AND ROTATE RETAINER CLIP 90 EXT Z AXIS INPUT 2 18V w DECREASES INTENSITY 238V BLANKS X Y THIS INSTRUMENT MAY BE PROTECTED Aor B SWEEP LINE VOLTAGE RANGE POWER MAX WATTS 100 MAX VA 155 FREQUENCY 48 440Hz BY ONE OR MORE U S OR FOREIGN PATENTS OR PATENT APPLICATIONS INFORMATION PROVIDED ON REQUEST FU
81. o the menu selection buttons Delay time and delta delay measurements for time frequency and phase are available in ALT and B Horizontal Modes The vertical deflection system consists of two channels with calibrated deflection factors from 2 mV to 5V per division in a 1 2 5 sequence of 11 steps and two channels with two basic deflection factors of 0 1 V and 0 5 V Use of coded probes having attenuation factors of 1X 10X and 100X extends the minimum sensitivity to 500 V per division VOLTS DIV readouts are switched to display the correct vertical scale factor when properly coded probes are attached to the vertical input connectors STANDARD ACCESSORIES The following items are standard accessories shipped with the 2246 instrument REV APR 1987 2 Probes 10X 1 5 meter with accessories 1 Power cord 1 Power cord clamp 1 Operators manual 1 Operators guide 1 Crt filter blue plastic installed 1 Fuse 2 A 250 V siow blow 1 Accessory pouch Ziploc For part numbers and further information about stand ard accessories and a list of the recommended optional accessories refer to Options and Accessories Section 7 in this manual For additional information on accessories and ordering assistance contact your Tektronix represent ative or local Tektronix Field Office PERFORMANCE CONDITIONS The electrical characteristics of Table 1 1 apply when the 2246 has been calibrated at an ambient temperature between 20 C
82. ode the signal applied to CH 1 OR X Input Connector produces the horizontal deflection X Axis Any of the vertical signal channels or ADD Tektronix 2246 may be selected to provide the vertical deflection Y Axis for an X Y display CALIBRATOR Connector Outputs a 0 5 V square wave signal at a frequency of approximately 1 kHz for use in compensating voltage probes and check ing the vertical deflection accuracy Auxiliary Ground Jack Provides an auxiliary signal ground connection between the equipment under test and the oscilloscope Hookup is made via a banana tip connector on the front panel Channel 3 and Channel 4 POSITION Controis Set the vertical position of the Channel 3 and Channel 4 signal displays Clockwise rotation of a control moves the associated trace upward counterclockwise rotation moves the trace downward When in X Y mode the associated Vertical POSITION control moves the display vertically Figure 3 3 Vertical connectors and CH 3 and CH 4 Controls and indicators co arc EEN EASIEST end oe a are EEE Channel 3 and Channel 4 VOLTS DIV Switches Select either of two basic deflection factors for Channel 3 and Channel 4 When the VOLTS DIV button light is off the deflection factor is 0 1 V per division using a X1 probe or a coaxial cable input connection when it is on the deflection factor is 0 5 V per division CH 3 and CH 4 input Connectors
83. ot be used for the active measurement that measure Measurement Processes and Applications 2246 Operators ment will be canceled without a message being displayed Returning to a mode that may be used and pressing the LAST MEAS MT button will restore the canceled measure ment mode if no other measurement selection is made first See Table 6 2 for compatible and incompatible modes The only Trigger MODE restriction is that gated voltage measurements will not run in SGL SEQ Trigger MODE Any gated measurement that is active will be canceled if SGL SEQ Trigger MODE is selected If a gated voltage measurement is selected while SGL SEQ is also selected the message NOT ALLOWED IN SSEQ is displayed for two seconds only if the menu is configured to remain on after the selection is made MEASUREMENT COMPATIBILITY AND ERROR MESSAGES The CH1 CH2 VOLTMETER measurements cannot be made when the signal is larger than the range of the B trigger level The displayed error message is OUCH TURN VOLTS DIV CCW The CHI CH2 VOLTMETER measurement of DC can not be made with the Input COUPLING set to AC the displayed error message is CH 1 or CH 2 SELECT DC COUPLING If GND Input COUPLING is in use a ground symbol is displayed after the readout value For PEAK PEAK and PK PK measurements the ac symbol will be displayed in AC input COUPLING and the ground symbol will be displayed in GND Input COUPLING The symbol
84. r is displayed in ALT or B Horizontal MODE both displayed in ALT if conditions are met NOTE If the TRACK rh auto tracking measurement is on only one of the TRIGGER LVL cursors will be on in ALT Horizontal MODE The A TRIGGER LVL cursor will be the default display if the the conditions are met to display an A TRIGGER LVL cursor Other wise it will be the B TRIGGER LVL cursor that is displayed when all the listed conditions have been met to display a B TRIGGER LVL cursor The labels for the Trigger Level cursors are ATL A trigger level BTL B trigger level The A and B Trigger LEVEL readouts include the sign the integer and decimal fractional value of the level and the units when a cursor is displayed For example ATL 3 25 mV POEreere rc reertr ci rerr rrr i retiree sires The A and B Trigger Level Cursors are not guaranteed to reach the waveform if the Horizontal POSITION control is set fully cw Also since the Trigger LEVEL cursor may be located anywhere within the viewing area and beyond the labels for those cursors may overlap each other or the PK PK and DC or TRACK mh cursor labels in the displays The trigger cursor channel is determined from the Trigger source as indicated in Table 6 3 Table 6 3 Trigger Cursor Channel A Trigger Source A Cursor Channel VERT Lowest numbered channel displayed CH 1 or CH 2 CH 1 CH 1 CH 2 CH 2 CH 3 Not used CH 4 Not used Not used
85. r less 35 C to 55 C 3 9 ns or less Delay Match CH 1 to CH 2 Less than 200 ps difference Common Mode Rejection Ratio CMRR At least 10 1 at 50 MHz for signals of eight divisions or less with VOLTS DIV VAR adjusted for best CMRR at 50 kHz Channel isolation Attenuation of deselected channel 10 MHz 100 MHz 2 mV Div to 0 5 V Div 50 dB or more 34 dB or more l Channel isolation tested with eight division input signal Trace Shift as VAR VOLTS DIV is Turned 1 division or less Invert Trace Shift 1 division or less Trace Shift Between VOLTS DIV Switch Positions 0 2 division or less Trace Shift Between GND and DC Input Coupling 10 C to 35 C Less than 0 5 mV 35 C to 55 C Less than 2 mV Position Range At least 11 divisions from graticule center Input Characteristics Resistance 1 MQ 0 5 Capacitance 20 pF 1 0 pF Capacitance Match Between Within 0 5 pF Any Two VOLTS DIV Settings in Each Channel Max Input Volts A 400 V dc peak ac 800 Y p p ac at 10 kHz or less 1 2 l REV MAR 1988 fue Specification 2246 Operators Fr Table 1 1 cont E a Characteristics Performance Requirements VERTICAL DEFLECTION SYSTEM CH 3 AND CH 4 Deflection Factors 0 1 V per division and 0 5 V per division Accuracy 15 C to 35 C 10 C to 55 C Frequency Response 3 dB bandwidth 10 C to 35 C Within 2 Within 3 DC to 100 MHz at the probe tip 35 C to 55 C DC to 90 M
86. r s Safety Summary at the front of this manual for power source grounding and other safety considerations pertaining to the use of the instrument Before connecting the oscilloscope to a power source read both this section and the Safety Summary CAUTION This instrument may be damaged if the wrong line fuse is installed LINE FUSE To verify the proper value of the instrument s power input fuse perform the following procedure 1 Press in the fuse holder cap and release it with a slight counterclockwise rotation 2 Pull the cap with the attached fuse inside out of the fuse holder 3 Verify proper fuse value 4 Install the proper fuse and reinstall the fuse holder cap POWER CORD This instrument has a detachable three wire power cord with a three contact plug for connection to both the power source and protective ground The power cord is secured to the rear panei by a cord set securing clamp The pro tective ground contact on the plug connects through the power cord protective grounding conductor to the accessible metal parts of the instrument For electrical shock protection insert this plug into a power source outlet that has a properly grounded protective ground contact Instruments are shipped with the power cord option ordered by the customer see Figure 2 1 Contact your Tektronix representative or local Tektronix Field Office for additional power cord information INSTRUMENT COOLING To prevent
87. r the phase measurement readout has units of degrees and is calculated by the following formula time difference x 360 reference time The reference time is the number of divisions set as the reference for 360 degrees using the l SET 360 l menu selection that appears along with the l PHASE I choice when phase measurements are selected If the reference is already set to the desired reference value pressing the I PHASE l menu selection exits the menu and activates the phase measurement mode l SET 360 I Permits resetting of the 360 refer ence for the l PHASE f measurements Cursor difference or DELAY TIME to ATIME difference is taken as the reference value when exiting the SET 360 refer ence function Set the desired time that represents the complete 360 degrees of a reference waveform using the l or DELAY and f or A controls then select l PHASE i to exit the menu and continue the phase measurement Recalling the LAST MEAS MT when l PHASE was the last selected measurement mode recalls the 360 degree reference as well SELF CAL Self characterizes the horizontal system SELF CAL may be performed at any time Suggested times are after a warmup period whenever the ambient operating temperature changes by 15 C and just prior to making any time measurements requir ing the best possible accuracy BEHAVIOR FOR HORIZONTAL MODE CHANGES if the Horizontal MODE is changed to a mode that can n
88. rsors Accuracy 1 6 Specifications for functions with digital readout are valid only when the ambient temperature is within 10 C of the tempera ture at the time of the last SELF CAL For maximum perform ance a recent SELF CAL is recommended 0 5 of reading 2 of one vertical division 250 uV Greater than 50 dB at 50 or 60 Hz 2 of reading 10 of one vertical division 1 mV 0 5 dB 3 dB 1 mV Follows the trigger system frequency response curve 2 0 of reading 10 of one vertical division 0 3 mV 0 2 division 50 ns or less 2 0 of reading 10 of one vertical division 1 5 mV 0 5 dB 3 dB 1 5 mV Follows the trigger system frequency response curve 2 0 of reading 10 of one vertical division 0 5 mV 0 2 division 50 ns or less 0 5 of reading 2 of the SEC DIV setting Readout calculated from l SEC I cursor positions 0 5 of reading 2 of the VOLTS DIV setting high frequency display errors 0 5 of reading 2 of the VOLTS DIV setting high frequency display errors Readout calculated from I SEC cursor positions REV OCT 1986 wd Sonsan ae 2 a Specification 2246 Operators Tabie 1 1 cont Characteristics Performance Requirements FUNCTIONS WITH DIGITAL READOUT cont CURSOR FUNCTIONS cont TRACK MEASUREMENT Position Accuracy Cursor position 0 05 vertical division on waveform versus dig
89. s will be displayed after the readout units The following measurements cannot occur when the VARIABLE VOLTS DIV knob for the channel being meas ured is not in the detent position PEAK PEAK PK PK DC GATED PEAK GATED PEAK GATED PK PK l VOLTS 3 1 and rh VOLTS 1 The displayed error message is VAR VOLTS DIV OUT OF DETENT The following measurements cannot occur when the VARIABLE SEC DIV knob for the channel being measured is out of the detent position Ik SEC I f 1 SEC l i PHASE l and l SET 360 1 The displayed error message is VAR SEC DIV OUT OF DETENT When in ALT or B Horizontal MODE and the B Trigger MODE is not RUNS AFTER a question mark will appear 6 5 Measurement Processes and Applications 2246 Operators Table 6 2 Behavior for Horizontal MODE Changes Measurement incompatible Mode Horizontal Modes Horizontal Modes l SEC l I 1 SEC 1 l PHASE l X Y DC PEAK PEAK PK PK ALT B GATED PEAK GATED PEAK GATED PK PK ALT B X Y before the delay time readout The readout value displayed is the delay time between the A trigger and the time a B trigger can be accepted by the trigger system A question mark will also appear in front of the delay time readout for delay measurements when the DELAY time is set to 0 25 division or less from the beginning of the sweep If the oscilloscope in not triggered when a gated voltage measurement mode is selected the follo
90. signal applied to the CH 1 input Two commen uses for ADD mode are 1 providing a dc offset to bring an ac signal riding on top of a large de voltage within the graticule viewing area and 2 canceling out a large line frequency signal component to view some smali feature riding on the waveform in greater detail using common mode rejection NOTE The following general precautions should be observed when using ADD mode 1 Do not exceed the input voltage rating of the oscilloscope or probe 2 Do not apply signals that exceed the equivalent of about eight times the VOLTS DIV switch settings since large voltages may distort the display For _ example with a VOLTS DIV setting of 0 5 V the voltage applied to that channel should not exceed av 3 Use CH 1 and CH 2 POSITION control settings which most nearly position the signal on each chan nel to mid screen when viewed separately This ensures the greatest dynamic range for ADD mode signal displays 4 To have similar responses for both channels use the same Input COUPLING for both CH 1 and CH 2 The following procedure shows how to eliminate an unwanted ac input power frequency signal component from the displayed signal 1 Set the front panel controis to obtain a baseline trace Use the settings given for making a PEAK volt age measurement but do not apply any signals and center the baseline trace vertically 2 Apply the signal of interest containing the unwanted
91. t de offset of the signal from ground level NOTE In this menu the select buttons toggle the choices on and off with each press and all three choices may be selected but not all displayed together because only two cursors are allowed Also press ing CLEAR DISPLAY as many as three times may be necessary does turn off the TRACK TRIG LVL and TRACK rh choices 6 Press either MENU OFF in the menu selection list or CLEAR DISPLAY once to remove the AUTO TRACK ING menu from the display NOTE If CH1 CH2 VOLTMETER PK PK measurement is selected two TRACK MEASMT cursors are required therefore the TRACK rh cursor will not be displayed 7 See Figure 6 7 The test signal used for the example has a de offset as shown by the position of the TRACK rh cursor and PEAK value peak ac dc as indicated by the voltage readout GATED VOLTAGE MEASUREMENT If you need to track the PEAK PEAK or PK PK voltage of a selected portion of a waveform that portion can be defined using the GATED MEASUREMENTS avail able in page 2 of the CH1 CH2 VOLTMETER menu The general steps given is the previous PEAK Voltage Measurement procedure are used for this function also Set up all the controls and apply the signal to be meas ured in the same way but after pressing the CH1 CH2 VOLTMETER button select the TO GATED MEASMT MENU choice After that follow these additional steps to make the gated measurement 1 Select GATED PEAK me
92. t functions are turned off as the second priority and finally the TRACK TRIG LVL and TRACK rh cursors are canceled as the third priority SET MEAS MT CHANNEL Calis up the source channel menu for the selected measurement The menu lists the possible input signa sources channels for the selected measurement mode see Table 6 1 in Section 6 for choices Pressing one of the Menu Select buttons designates that channel as the signal source for the measurement and clears the menu from the display If nO measurement mode is in effect when the button is pressed the message SELECT A MEASUREMENT is displayed for two seconds Controis Connectors and indicators 2246 Operators Tektronix 2246 i EP EP acl oo 6083 09 Figure 3 7 Menu Controls then cleared If a measurement mode not requir ing a measurement channel to be selected is active such as a Cursor Time Measurement mode the message NO MEAS CHANNEL NEEDED is displayed for two seconds Changing the Horizontai MODE A to ALT or B to X Y or vice versa while the SET MEAS MT CHANNEL menu is being displayed turns off the measurement mode in effect and clears the chan nel select menu from the display LAST MEAS MT Recalls and initializes the last active measurement mode if none is active or reinitializes an active measurement mode The measurement mode and measurement value are displayed at the top of the screen LAST MEAS
93. the Channel 1 and Channel 2 VOLTS DIV switch settings when ADD mode is on Press the ADD button a second time to turn off the ADD button light and remove the ADD trace from the display NOTE In ADD mode the algebraic sum of Channel 1 and Channel 2 display is the only signal source for the trigger system when either AUTO LEVEL TRIGGER MODE or CHOP VERTICAL MODE is selected Channel 1 and Channel 2 VOLTS DIV Switches Select the calibrated deflection settings for Channel 1 and Channel 2 from 2 mV per division to 5 V per division in a 1 2 5 sequence of 11 steps The switches are detented continuous rotation con trols with no end stops The VOLTS DIV switch set ting displayed in the crt readout reflects the attenua tion factor of coded attenuator probes that are con nected to the vertical inputs VOLTS DIV VAR Controis Provide for adjustable vertical deflection between the calibrated settings of the Channel 1 and Channel 2 VOLTS DIV switches The controls vary the deflection factors from cali brated fully clockwise detent position to at least 2 5 times the calibrated deflection factor fully counter clockwise position When a VAR control is out of its detent position a greater than gt sign appears on the left side of the associated VOLTS DIV readout display to indicate a deflection factor greater than the VOLTS DIV switch setting REV OCT 1986 a Toa et a Fi Fe TA ma 3 L aa a I red Run
94. the positive direction see Figure 6 14A The Hor izontal POSITION control may be used as necessary to center the waveform period in the viewing area 9 Position the A cursor to the second positive cross ing of the center horizontal graticule line by the reference waveform as shown in Figure 6 14A 10 Select I PHASE i to set the new reference value and continue the phase measurement REV APR 1987 Measurement Processes and Applications 2246 Operators 11 Apply the phase shifted sine wave signal to be measured to the CH 2 input connector using a 10X attenuator probe and turn CH 2 VERTICAL MODE on to display the signal 12 Set the VOLTS DIV and VOLTS DIV VAR controls to match the amplitude of the phase shifted signal to that of the reference waveform as shown in Figure 6 14B Use the VERTICAL POSITION contro as necessary to align the two waveforms vertically 13 Reposition the second cursor to the first positive crossing of the phase shifted signal and read the phase difference NOTE For increased resolution of the phase measurement the sweep many be increased and both cursors repositioned to the measurement points see Figure 6 14C The X10 MAG feature may also be used in a similar manner by placing the measurement points at the center vertical graticule line before pressing the X10 MAG button you may want to reduce the A SEC DIV setting prior to turning on the X10 MAG feature DELAY TIME MEASUREMENTS The
95. the waveform is controlled by the l or DELAY control and width of the gated region is controlled by the l or A control Some features of the CH1 CH2 VOLTMETER function are a Measures either CH 1 or CH 2 while viewing any channel Select the measurement source channel using the SET MEAS MT CHANNEL menu b Measures signal levels DC values and peaks in SGL SEQ single sequence Trigger MODE continu ously Use CONFIGURE to get menus and readouts to remain on between single sequence triggers c Finds peaks of signal applied not only just the displayed portions of the waveform d Defines a portion of the waveform GATED measurements especially useful for making measure ments on a multi level signal on which to make the selected measurement Use page 2 of the CH1 CH2 VOLTMETER menu to select a GATED measurement mode NOTE Very narrow gated measurements at 20 ns per div sweep speed are impractical due to imprecise definition of the intensified zone at that sweep speed PEAK VOLTAGE MEASUREMENT Setup for Front Panel Controis The following procedure is a general front panel setup for making any type of CH1 CH2 VOLTMETER or CUR SORS measurement on an unknown signal Use it as a guideline to set up for your specific measurement applica tions The control settings used in the procedure should produce a triggered viewabie display for most input signal types Certain signals such as video or aperiodic sign
96. tion or instrument malfunction is noted refer the instrument to a qualified service person INITIAL SETUP 1 Press in the POWER switch button ON and allow the instrument to warm up 20 minutes is recommended for maximum accuracy 2 Set the instrument front panel controls to obtain a baseline trace Vertical Controls POSITION Midrange VERTICAL MODE CH 1 VOLTS DIV tV Channel 1 COUPLING GND Horizontai Controls POSITION Midrange MODE 2 A X10 MAG Off A SEC DIV 0 1 ms SEC DIV VAR Cal detent Trigger Controls A B SELECT A MODE AUTO SOURCE VERT CPLG DC 3 Adjust the A INTEN READOUT and FOCUS con trois for desired brightness and best trace and readout definition 4 Adjust the Vertical and Horizontal POSITION con trols to center the trace within the graticule area TRACE ROTATION ADJUSTMENT 1 Preset instrument controls and obtain a baseline trace as described in initial Setup Position the trace vertically to align it with the center horizontal graticule line and check that the trace is parallel with the graticule line NOTE Normally the resulting baseline trace will be parallel to the center horizontal graticule line and the TRACE ROTATION adjustment will not be needed 2 if the baseline trace is not parallel to the center hor izontal graticule line use a small straight blade screwdriver or alignment tool to adjust the TRACE ROTATION pot for proper alignment of the trace PROBE LOW FR
97. to achieve the accuracy stated in the Specification section of this manual The SELF CAL choice found in either the CH1 CH2 VOLTMETER menu or the ATIME menu calibrates the associated circuitry either vertical for voltage measure ments or horizontal for timing measurements Any time the user requires the highest degree of measurement accuracy possible of the 2246 especially the CH1 CH2 VOLTMETER measurements the SELF CAL routine may be run Both vertical and horizontal calibration will be done when using the SELF CAL MEASUREMENTS choice in the INTERNAL SETTINGS MENU Pressing the down arrow three times from the entry level to the SERVICE menu underlines the INTERNAL SETTINGS MENU label and displays the SELECT label Press SELECT to display the menu shown in Figure 6 6 INTERNAL SETTINGS MENUS MAKE FACTORY SETTINGS t MENU ADJUST VERTICAL OUTPUT 4 SELF CAL MEASUREMENTS 6083 20 Figure 6 6 Internal Settings Menu Press the down arrow three times again to underline ine SELF CAL MEASUREMENTS choice then press the RUN button that appears in the menu At this point the instrument automatically does a self characterization of the CH 1 and CH 2 Vertical channels first and then the horizontal timing Upon completion of the procedure the INTERNAL SETTINGS MENU choices are again displayed Press QUIT to return to the oscilloscope operation mode MAKE FACTORY SETTINGS This menu selection sets up the front panel contro
98. ude is not sufficient or if the repetition rate of the applied signal is too slow the B TRIGGER MODE operation reverts to RUNS AFTER to pro duce an untriggered baseline display See Table 3 1 for critical triggering intervals that will result in a free running B Sweep The resulting trace will appear to be triggered if the A Sweep is trig gered but the TRIG D LED will not be on and the DELAY control will move the displayed B trace signal smoothly rather than from trigger point to trigger point as would be expected for a triggered B Sweep Peak signal levels will be measured from the start of the delay time to the end of the A Sweep if the measurement time interval does not exceed 500 ms If the measurement time exceeds 500 ms the peak signal limits will be measured over the entire A Sweep The signal trigger level is reacquired for the same conditions described in A TRIGGER MODES for AUTO LEVEL The B Trigger signal AUTO LEVEL peak measurements will not be done if the A Trigger MODE is SGL SEQ RUNS AFTER Starts the B Sweep immediately after the delay time selected by the l OR DELAY control l REV APR 1987 Controls Connectors and Indicators 2246 Operators RUNS AFTER Trigger MODE is forced on if tim ing measurements other than Delay are selected when the Horizontal Mode is ALT or B Delayed NORM The B Sweep is initiated when an ade quate trigger signal is received after the delay time condition has been met In t
99. urethane foam tightly packed between the carton and the instrument 5 Seal the shipping carton with an industrial stapler or strapping tape 6 Now mark the address of the Tektronix Service Center and also your own return address on the shipping carton in two prominent locations r F L T j E ji P mad E Section 3 2246 Operators CONTROLS CONNECTORS AND INDICATORS CRT POWER and DISPLAY See Figure 3 1 for items 1 through 9 POWER Switch Turns instrument power on and off Press in for ON press again for OFF Power on is indicated by the front panel control but tons At least one of the back lighted buttons will be lit at any time the instrument is on Front panel switch settings present at power off will be returned when power is reapplied to the instrument except for the menus and the B SEC DIV switch setting if different than the A SEC DIV switch setting The A AND B SEC DIV settings are locked together at power up Potentiometer settings are not retained in memory Tektronix 2246 2 A INTEN Control Adjusts brightness of the A trace Brightness is increased when the control is rotated clockwise B INTEN Contrel Adjusts brightness of the B Delayed Sweep trace and the intensified zone on the A trace Brightness is increased when the control is rotated clockwise FOCUS Control Adjusts the traces readout and cursors for optimum d
100. way the button operates Selecting a positionable cursor measurement mode from Page 1 prevents any of the tracking cursors from being displayed but does not dis able the selection in Page 2 of the menu Enabled tracking cursors will be returned to the display as their priority permits Displayed cursors are labeled to distinguish one type from another see Figure 3 10 In addition to being enabled in the Page 2 menu the appropriate settings of VERTICAL MODE REV APR 1987 Controls Connectors and Indicators 2246 Operators VOLTMETER PK PK SELF CAL TO GATED MEASMT MENU VOLTS PG 2 GATED GATED GATED BACK TO PREVIOUS 6083 10 Figure 3 8 CH1 CH2 VOLTMETER Measurement Menus Trigger SOURCE Trigger MODE Trigger CPLG and Horizontal MODE must be made for the TRACK TRIG LVL cursor to appear in the display TRACK rh cursors must only be enabled and have either CH 1 or CH 2 VERTICAL MODE on When a l VOLTS l or a rh VOLTS i measure ment mode is first selected either by direct selec tion or as a result of pressing the LAST MEAS MT button the voltage measurement cur sor positions are initialized For l VOLTS 1 the SmartCursors are set at the plus peak and minus peak values of the lowest number displayed waveform of CH 1 or CH 2 For rh VOLTS I the active cursor is set to the plus peak The l VOLTS I cursors may be used to 3 13 CURSORS CURSORS PG 2 Controls Conne
101. will not be turned off when deselected as a measurement source Extra display channels must be turned off using the VERTICAL MODE buttons If a channel is displayed but not selected as a measurement source that waveform trace will not be intensified and no alternate B Delayed trace will be displayed for that channel 6 Using the center horizontal graticule line as a refer ence point set the reference delay to align the point of interest to be measured point A in Figure 6 15 from to that reference point with the l OR DELAY control Set the A delay to align the second point of interest displayed in the second B Sweep point B in Figure 6 15 to the refer ence point using the OR A control The measured Measurement Processes and Applications 2246 Operators Z difference between the two delays is displayed at the top of the screen EIRST POINT OF INTEREST TIME DIFFERENCE Once the measurement points are identified the A Intensified Sweep traces may be removed from the dispiay for ease in viewing the B Sweep traces by switching to B Delayed Horizontal MODE In B Horizontal MODE exact placement of the two delays may be obtained by position ing one trace over the other and then aligning the mea surement point using the OR A control Additional reso lution may be obtained by advancing the B SEC DIV switch setting to further expand the B Sweep traces REFERENCE SECOND POINT OF INTEREST GRATICULE LINE 6083 29
102. wing error mes sage is displayed LO REP RATE STILL TRYING This can happen if the selected trigger channel has no trigger signal applied in NORM Trigger MODE or if the Trigger LEVEL control is not set to obtain a triggered display An improperly triggered display in either AUTO LEVEL or AUTO Trigger MODE will cause the measure ment readout value to be unstable but no error message will be displayed MEASUREMENT BEHAVIOR IN SINGLE SEQUENCE MODE The following measurements run continuously during SGL SEQ Trigger MODE DC PEAK PEAK PK PK l VOLTS l rh VOLTS I I SEC 1 l 1 SEC 31 and l PHASE The readout and or cursors are displayed briefly during single sequence mode for making a photographic record or they may be configured to remain on see the SER VICE MENU discussion The displayed readout is the value of the measurement at the instant it is displayed GATED PEAK GATED PEAK and GATED PK PK measurements are not available during single sequence mode and will be canceled if active when SGL SEQ is selected 6 6 B Trigger AUTO LEVEL acquisitions do not occur when the A Trigger MODE is SGL SEQ lt SERVICE MENU The SERVICE menu contains operating choices not normally accessed by the operator Most of the choices are for diagnostics troubleshooting and calibration Expla nation of those choices are left to the servicing documen tation One of the INTERNAL SETTIN
103. xternal Z Axis signal does not affect the readout or the intensified zone intensity 30 V dc peak ac 30 V p p ac at 1 KHz or less Represents less than one LSTTL load CALIBRATOR OUTPUT 0 1 or less 0 5 V 2 into 1MQ load 1 kHz 25 FRONT PANEL SETUP MEMORY At least three years REV FEB 1988 na 1 pr Saunen t a Specification 2246 Operators Tabie 1 1 cont Characteristics Performance Requirements EEE EEE EEE EEE NN Aer AAAA AA AAA ne DD ARE EEE ENTE POWER SOURCE Line Voltage Range 90 Vac to 250 Vac Line Frequency 48 Hz to 445 Hz Line Fuse 2 A 250 V fast blow Max Power Consumption 80 Watts 110 VA CRT DISPLAY Display Area 8 by 10 cm Geometry Vertical 1 2 minor 0 1 div at 8 by 8 cm centered area Horizontal 1 2 minor 0 1 div at 8 by 10 cm centered area Trace Rotation Range Adequate to align trace with center horizontal graticule fine Standard Phosphor P31 Y Axis Orthogonality 0 1 division or less over eight vertical divisions No adjustment Nominal Accelerating Voltage 16 5 kV Specification 2246 Operators Table 1 2 Mechanical Characteristics Weight Instrument Alone Instrument with Probes Power Cord and Manual Shipping Weight Domestic Overali Dimensions Height With Feet and Accessories Pouch empty Without Accessories Pouch Width With Handle Depth With Front Cover With Handle Extended Cooling Finish Construction
104. ys X10 Magnifier Registration X10 to X1 Variabie Control Range Sweep Length Delay Time Delay Control Range Jitter Delta Time Deita Control Range 1 4 0 5 s div to 20 ns div in a 1 2 5 sequence X10 magnifier extends maximum sweep speed to 2 ns div 5 0 ms div to 20 ns div in a 1 2 5 sequence X10 magnifier extends maximum sweep speed to 2 nsidiv Unmagnified Magnified 2 3 3 4 Sweep Accuracy applies over the center eight divisions Excludes the greater of the first 1 4 division or 25 ns from the sweep start of the magnified sweep and anything beyond the 100th magnified division 5 Able to move the start of the sweep to the right of the center vertical graticule able to move a time mark corresponding to the end of the tenth division of an unmagnified sweep to the left of the center graticule At least 13 divisions Expands the normal sweep by ten times around that portion of the sweep positioned at the center vertical graticule line 0 5 division or less shift Continuously variable between calibrated SEC DIV switch set tings Extends both the A and B sweep time per division by at least a factor of 2 5 Greater than 10 divisions Less than 0 1 division to 10 times the A SEC DIV switch setting Maximum value does not exceed end of the A Sweep 1 part in 20 000 or less peak to peak during a two second time interval 0 to greater than 9 9 divisions to the right of setting of DELAY

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