2445/2465 OPTION 05 - UCSD Department of Physics
Contents
1. System M protocol is currently selected LINE 1 COINCIDENT WITH FLD SYNC Nonsys tem M protocol is currently selected 3 2 4 If the desired protocol message is not displayed push up and release the TRIGGER COUPLING switch once The desired protocol message should now be displayed Push down once on the TRIGGER COUPLING switch To choose or determine the line number format 5 Push up and release the TRIGGER MODE switch The message TV EXER 62 will be displayed at the bot tom left corner of the crt 6 Push up and release the COUPLING switch once to display the currently selected format at the top of the crt The message meanings are as follows LINE NO RESETS ON EACH FIELD Format 1 is selected LINE NO RESETS ON FLD 1 ONLY Format 2 is selected 7 If the desired line format message is displayed exit the Diagnostic Monitor by pushing the A B TRIG button to resume normal oscilloscope operation 8 If the desired line format message is not displayed push up and release the TRIGGER COUPLING switch once The desired line format message should now be displayed 9 Push the A B TRIG button to exit the Diagnostic Mon itor and resume normal oscilloscope operation Section 4 2445 2465 Option 05 Operators OPERATING CONSIDERATIONS Consult the oscilloscope Operators manual to acquire a thorough understanding of the operation of the basic instru ment before trying to use the features of the TV Option With2. back porch clamp when the switch is pushed up from the 1 MQ AC position The AC indicator LED will remain on and the message TVC will appear on the top line of the crt The clamp sets the television signal back porch amplitude to a constant dc level and eliminates vertical drift hum and tilt in the display A stable display is provided despite changes in sig nal amplitude and average luminance levels The TV back porch clamp can be enabled even if TV trigger is deselected AC Deactivates the TV back porch clamp when the switch is pushed down once from the UP TV CLAMP position The AC indicator LED will remain on and the message TVC will be removed from the top of the crt The television signal s level will then be set by the average signal level and vary with that average level 32 A FLD LINE Control Selects a specific line number within the field for triggering the oscillo scope when the TV Option is enabled and the Trig ger COUPLING switch is set to FLD 1 FLD 2 or alternate FLD 1 FLD 2 mode Possible line numbers range from 1 to the maximum number of lines per frame in the television signal being viewed Rotating the control clockwise increases the line number ro tating it counterclockwise decreases the line num ber See the A FLD LINE Control discussion in the Operating Considerations section of this man ual for further information about using this control When the line number settin
3. displayed when Field 2 is selected even fields On noninterlayed scan systems the TV Option detects start of field information only Field 1 and Field 2 are then two consecutive fields of information 4 1 Operating Considerations 2445 2465 Option 05 Operators MULTI TRACE MODES When using the TV trigger and multi trace operation the trigger source must not be VERT mode When only one trace is displayed the VERT position of the TRIGGER SOURCE switch may be used OVERSCANNED DISPLAYS For various video measure ments it may be desirable to magnify the video waveform vertically beyond the limits of the screen Under these cir cumstances the trigger amplifiers or the option circuitry may be overloaded blocking out some sync pulses in the vicinity of strong video transitions or losing sync pulses al together To avoid overload problems use one of the other vertical channets to supply a constant amplitude signal to the option circuitry while the overscanned observations are being made RF INTERFERENCE Operation in the vicinity of some FM and TV transmitters may contain objectionable amounts of rf signal energy in the input signal even when coaxial input connections are used The front panel 20 MHz BW LIMIT switch will usually eliminate such interference from the display but will not affect the signal reaching the option circuitry Where the rf interferes with option operation ex ternal filters will be required MULTIPLE DIS
4. instrument then functions adequately for your particular measurement requirement it can be used but refer it to a qualified service technician for repair of the problem as soon as possible Successful Power Up Sequencing When the power up routine is successfully completed without a failure indication the oscilloscope enters the nor mal operation state The oscilloscope parameters are set to correspond with current front panel switch positions and with switch functions that were established for at least 10 seconds before instrument power was last turned off The instrument is now ready to make measurements as required POWER DOWN SEQUENCE When the POWER switch is set to OFF the instrument powers down and the instrument front panel settings that were unchanged for at least 10 seconds prior to power off will be stored for use the next time power is applied to the instrument TV PROTOCOL AND LINE NUMBERING FORMAT SELECTION The following procedures are used to select a particular protocol or line numbering format Both involve access to Diagnostic Monitor routines EXER 61 and EXER 62 and affect field triggering only FLD 1 Alternate FLD 1 FLD 2 or FLD 2 TV protocol selection allows the user to choose be tween system M and nonsystem M protocols Selecting the incorrect system for a given TV protocol will not affect the ability to trigger on a given TV waveform It will however cause the line number displayed to be inaccurate
5. may be set to a low number An error code may then result on the GPIB controller when an at tempt is made to change the line number to what is believed to be a valid line number over the GPIB 4 3 Operating Considerations 2445 2465 Option 05 Operators Header ATRigger ATRigger TVClamp TVClamp TVLine TVLine LCNTStart LCNTStart LCNTReset LCNTReset ID 44 Table 4 1 GPIB Command Set for the TV Option COUpling FLD1 Selects TV option trigger mode from list FLD2 These commands are in addition to the A ALTernate trigger commands used by the main LINES instrument PLUs MINUs Query returns ATR COU string SLO string where string is one of the respective argument parameters Causes the CH 2 input coupling to be switched to AC and the TV back porch clamp to be active OFF If the TV back porch clamp is enabled the CH 2 input coupling is switched to AC and the TV back porch clamp is turned off Otherwise no change to the CH 2 input coupling occurs Query returns either TVC ON or TVC OFF lt nrx gt is the TV line number chosen to trigger the oscilloscope Query returns present line number displayed PREFId M Line count begins 3 lines before field sync pulse System M Line count begins at field sync pulse Nonsystem M Query returns Line 1 definition either LONTS PREF or LCNTS ATF Line count is reset only on field 1 Format 2 Both field 1 and field 2
6. of the manual contains information related to the power up of the main instrument containing the TV Option The power up sequence of the oscilloscope is de scribed along with explanations of potential option related error messages that may occur if the instrument is not func tioning properly Also included is initial setup information for the selection of the TV protocol and line number format parameters POWER UP SEQUENCE Before turning on power to the instrument read Section 2 Preparation for Use in the oscilloscope Operators man ual and follow the safety and precautionary information de scribed there The power up tests automatically performed each time the oscilloscope is turned on test both the standard oscillo scope circuitry and the TV Option circuitry Tests specifically applicable to the TV Option are integrated into the power up tests for the host oscilloscope and include the TV Kernel test Kernel Test Operation of the TV Option memory ROM is checked by the standard instrument Kernel test Kernel test failures will result in an attempt to flash the front panel A SWP TRIG D indicator NOTE On some instruments having other options installed the A B TRIG button may be labeled A B MENU Even with a Kernel failure pressing in the A B TRIG Switch may still place the instrument in an operating mode However if the operating mode is successfully entered in strument operation may be unpredictable If the
7. symbol appears in the crt readout display following the line number If a delta symbol is not displayed the control is used to position the A cursor for the At 1 At or AV func tions The following two paragraphs describe how to switch the function of the control from one to the other during a series of measurements To enable the control to select a TV line when it is cur rently controlling the 4 cursor press the TRIGGER COU PLING switch once This will not change the current coupling mode selected and the A symbol will appear in the crt readout next to the line number If the control is currently controlling TV line number selec tion and it is desired to make a At 1 At or AV measure ment press in the At button to get the At function both the At and AV buttons to get the 1 At function or the AV button to get the AV function The control can now be used to position the A cursor Slope Selection When using the TV trigger select the proper slope for triggering on the TV signal For sync negative displayed sig nals set the SLOPE switch to When triggering on sync positive displayed signals set the SLOPE switch to Display Considerations The TV Option circuitry does not detect the color burst phase or Bruch Sequence color burst blanking information In a four field Pal Sequence with Bruch Sequence color burst blanking Fields 1 and 3 will be displayed when Field 1 is selected odd fields and fields 2 and 4 will be
8. 2465 Option 05 Operators TABLE OF CONTENTS Page LIST OF ILLUSTRATIONS ii LIST OF TABLES LL ii OPERATORS SAFETY SUMMARY iii Section 1 SPECIFICATION INTRODUCTION 1 1 STANDARD ACCESSORIES 1 1 PERFORMANCE CONDITIONS 1 1 Section 2 CONTROLS AND INDICATORS FRONT PANEL CONTROLS 2 1 READOUT DISPLAYS 2 3 Section 3 PREPARATION FOR USE POWER UP SEQUENCE 3 1 Kernel Test 0000 eee 3 1 Successful Power Up Sequencing 3 1 POWER DOWN SEQUENCE 3 1 TV PROTOCOL AND LINE NUMBERING FORMAT SELECTION 3 1 Page Section 4 OPERATING CONSIDERATIONS FRONT PANEL CONTROL AND SETUP CONSIDERATIONS 4 1 TN Clamp iuo er nee 4 1 A FLD LINE Control 4 1 Slope Selection 4 1 Display Considerations 4 1 Oscilloscope Dc Balance Routine 4 2 Front Panel Update 4 2 CH 2 SIGNAL OUT Connector 4 2 IDENTIFYING FIELDS FRAMES AND LINES IN 525 60 AND 625 50 TV SYSTEMS cose sows ade ER ET 4 2 NTSC CCIR System M 4 2 CCIR System B and Similar 625 50 Systems including PAL 4 2 GPIB CONTROLLABLE FUNCTIONS 4 3 Section 5 BASIC APPLICATIONS Initial Setup 2 0 20 0 0 0 5 1 Signal Input Coupling 5 1 Time Interval Measurements 5 2 Voltage and IRE Measurements 5 2 CHANGE INFOR
9. 50 Systems including PAL In most 625 line 50 Hz field rate systems identification of parts of the picture relies primarily on continuous line numbering rather than on field and line identification except for PAL systems The CCIR frame starts with the first wide vertical sync pulse following a field which ends with a half line of video The first line after the second equalizing interval is line 6 the first picture line is line 23 half line of video The first field of the frame contains lines 1 through the first half of line 313 and the picture ends with a full line of video line 310 The second field of the frame commences with the lead ing edge of the first wide vertical sync pulse middle of line 313 and runs through line 625 end of equalizing interval The first full line after the equalizing interval is line 318 the picture starts on line 336 full line The first field is referred to as odd and the second field as even Note that the identification systems for System M and System B are reversed In the four field PAL sequence with Bruch Sequence Color burst blanking the fields are identified as follows Field 1 Field that follows a field ending in a half line of video when preceding field has color burst on the last full line Field 1 lines are 1 through 312 and half of line 313 Color burst starts on line 7 of field 1 a half line of video appears on line 23 Field 2 Field that follows
10. ATIVE TV option will select sync negative when entering TV trigger DEFSLOPE TV option sync selection will default to the A trigger slope prior to this version MV2 DEFSLOPE has been the only possible selection After entering exer 63 the display will read TVSYNC POSITIVE OR TVSYNC NEGATIVE OR TVSYNC SLOPE DEFAULT Selection is controlled by the trigger coupling switch An up push when TVSYNC is POSITIVE will change the selection to NEGATIVE the next up push will change to DEFSLOPE the next up push will return to POSITIVE A down push will exit exer 63 and store the last state displayed Push the A B TRIG button to exit the diagnostic monitor Page 4 1 Slope Selection Replace the Slope Selection paragraph with the following When using the TV trigger the A trigger slope controls the polarity of sync on which the option will trigger For sync negative displayed signals set the slope to When triggering on sync positive displayed signals set the slope to Page 4 4 Table 4 1 Add the following command to the table Header Comments POSITIVE Sync is set to positive when activating the TV trigger NEGATIVE Sync is set to negative when activating the TV trigger DEFSLOPE Sync defaults to the present value of the A trigger slope when activating the TV trigger Page 2 of 2 001 0057 00D
11. Line numbering format selection allows the user to select a pre ferred line numbering scheme Format 1 references line one from the beginning of the field being used for trigger refer ence Format 2 always references line one from the first line of Field 1 Exercise procedure TV EXER 61 accessed via the oscil loscope Diagnostic Monitor allows the user to select be tween system M and nonsystem M television protocols When system M is selected the line count begins three lines before the field sync pulse is encountered If nonsystem M is selected the line count begins coincident with the field sync pulse 3 1 Preparation For Use 2445 2465 Option 05 Operators Exercise procedure TV EXER 62 accessed via the oscil loscope Diagnostic Monitor allows the user to select one of two line number formats as shown below Format 1 1 1 2 263 112 262l Format 2 1 2 263 1264 525l Field 1 2 FLD LINE Control Rotation CCW 4 9 CW To choose or determine the TV protocol 1 Hold in both the AV and At buttons and push in the TRIGGER SLOPE button to enter the Diagnositic Monitor 2 Repeatedly push up and release the TRIGGER MODE switch until the message TV EXER 61 appears at the bottom left corner of the crt 3 Push up and release the COUPLING switch once and the currently selected protocol will appear at the top of the crt The message meanings are as follows LINE 1 OCCURS PRIOR TO FLD SYNC
12. MATION 2445 2465 Option 05 Operators LIST OF ILLUSTRATIONS Figure Page The 2445 Option 05 TV Oscilloscope 6 ec teen eens iv The 2465 Option 05 TV Oscilloscope LIED iv 2 1 TV Option front panel controls llsisssssssllleese eee 2 2 5 1 Appearance of video signal with CH 2 Input Coupling switch positions 5 1 LIST OF TABLES Table Page 1 1 Option 05 Electrical Characteristics llle IA 1 2 1 2 Option 05 Mechanical Characteristics 2 0 cece cee eens 1 3 4 1 GPIB Command Set for the TV Option 0 0 2 cece eee eee eens 4 4 2445 2465 Option 05 Operators OPERATORS SAFETY SUMMARY The general safety summary 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 ac cessible as one reads the marking Symbols as Marked on Equipment h This s
13. PLAYED WAVEFORMS Within a given frame the color burst alternates phase every line Since there are an odd number of lines per frame on interlaced scan systems a given line within a frame will alternate color burst phase between frames This is readily apparent when viewing a specific line within a frame Understanding this color burst phasing and how A and B sweeps are triggered is important when interpreting multiple displayed waveforms Review the base instrument operators manual parts on horizontal and delta measurements and delayed sweep operation In A Alt B mode the sweeps are displayed as follows A sweep delayed B sweep A sweep delayed B sweep In this mode if At mode is selected and Fld 1 or Fld 2 trigger is selected sweeps occur in the following order A sweep B sweep A sweep B sweep Note that since B sweeps are essentially interlaced with the A sweep each A and B sweep is triggered on every other frame Since color burst phase alternates on every frame the A and B displayed waveforms will each show one phase of the color burst information If A only or B only sweep mode is selected sweeps are triggered on every frame and the displayed waveform will show both phases of the color burst 4 2 Oscilloscope Dc Balance Routine With the TV Option installed the main instrument dc bal ance routine can be accomplished with the CH 2 Input Cou pling switch in either the 1 MQ AC position or the TV CLAMP po
14. Tektronix COMMITTED TO EXCELLENCE PLEASE CHECK FOR CHANGE INFORMATION AT THE REAR OF THIS MANUAL 2445 2465 OPTION 05 TV OPTION OPERATORS INSTRUCTION MANUAL Tektronix Inc P O Box 500 Beaverton Oregon 97077 Serial Number 070 4629 00 First Printing OCT 1983 Product Group 38 Revised MAY 1984 Copyright 1983 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 f are registered trademarks of Tektronix Inc TELEQUIPMENT is a registered trademark of Tektronix U K Limited 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 2445
15. Trigger COUPLING switch is set to any of the TV trigger modes FLD1 FLD2 ALT or LINES and scale factors are on or when the TV back porch clamp is active and scale factors are on Page 3 1 Add the following section FILTER GRATICULE REPLACEMENT The plastic filter or graticule over the crt faceplate can be removed by sliding the filter or graticule up until the bottom edge is exposed Pull the bottom edge out and slide the filter or graticule down Page 3 2 Add the following line to part 8 Push down once on the TRIGGER COUPLING switch Page 3 2 Add the following section AUTOMATIC SYNC SELECTION Automatic sync selection is a feature which allows the user to preselect the polarity of sync used most often Automatic sync selection will change the sync to the preselected polarity when the user enters a TV trigger coupling selection Once TV trigger has been activated the user may change the polarity as desired Changing trigger coupling selections within the TV option area will not cause the sync selection to be changed Page 1 of 2 000 2775 00D C2 0784 2445 2465 OPT 05 OPERATORS Date 7 16 84 Product Change Reference DESCRIPTION An exerciser EXER 63 routine controls this function The TV option can be set up to automatically select the desired sync when entering the TV trigger There are three possible selections for exer 63 POSITIVE TV option will select sync positive when entering TV trigger NEG
16. a field ending in a full line which does not carry color burst Field 2 lines are the last half of line 313 through line 625 Color burst starts on line 319 one line without burst following the last equalizing pulse a full line of video appears at line 336 Operating Considerations 2445 2465 Option 05 Operators Field 3 Field that follows a field ending in a half line when preceding field has no color burst on its last full line Field 3 lines are 1 through the first half of line 313 Burst starts on line 6 immediately following the last equalizing pulse a half line of video appears on line 23 Field 4 Field that follows a field ending in a full line carrying color burst Field 4 lines are the second half of line 313 through line 625 Color burst for field 4 starts on line 320 two full lines without burst follow the last equalizing pulse video starts with a full line on line 336 GPIB CONTROLLABLE FUNCTIONS If the GPIB Option is installed in the instrument addi tional commands to control the TV Option via the GPIB are available The commands are listed in Table 4 1 and only the upper case characters of a command are required for recognition See the GPIB Operators manual for additional information relating to GPIB operation When using the GPIB to set the field line number the option should be stably triggered on a valid composite video or composite sync waveform If it is not stably triggered the max line in the option
17. be a percentage which will correspond with the IRE measurement units MANUAL CHANGE INFORMATION At Tektronix we continually strive to keep up with latest electronic developments by adding circuit and component improvements to our instruments as soon as they are developed and tested Sometimes due to printing and shipping requirements we can t get these changes immediately into printed manuals Hence your manual may contain new change information on following pages Asingle change may affect several sections Since the change information sheets are carried in the manual until all changes are permanently entered some duptication may occur If no such change pages appear following this page your manual is correct as printed a u gt F4 a m 2 t c z td c a b Tektronix MANUAL CHANGE INFORMATION COMMITTED TO EXCELLENCE Date 7 16 84 Change Reference C2 0784 Product 2445 2465 OPT 05 OPERATORS Manual Part No 070 4629 00 DESCRIPTION PG 38 EFFECTIVE ALL SERIAL NUMBERS TEXT CHANGES Page 1 3 TRIGGERING Add the following to the Performance Requirements for Sync Separation For noninterlaced scan systems the video signal source must start and end with full lines of video for correct line identification in the field trigger modes Page 2 3 READOUT DISPLAYS In the second paragraph replace the first sentence with the following The crt readout will display TV Trigger information when the
18. btained from sync positive or sync negative interlaced or non interlaced scan composite video signals having 525 to 1280 horizontal lines per frame and 50 or 60 Hz field rates STANDARD ACCESSORIES In addition to the standard accessories listed in the basic oscilloscope manuals the following TV Option accessories are provided Quantity Description Part Number 1 2445 2465 Option 05 070 4629 00 TV Option Operators Manual 1 2445 2465 Option 05 070 4630 00 TV Option Service Manual 1 CCIR Graticule 378 0199 01 1 NTSC Graticule 378 0199 02 1 Polarized Viewing Hood 016 0180 00 PERFORMANCE CONDITIONS Except as noted in Tables 1 1 and 1 2 of this manual the electrical environmental and mechanical characteristics of TV Option instruments are identical to those specified for basic instruments in the respective 2445 and 2465 Oscillo scope manuals 1 1 Specification 2445 2465 Option 05 Operators Table 1 1 Option 05 Electrical Characteristics Characteristics Pertormance Requirements VERTICAL DEFLECTION SYSTEM CHANNEL 1 AND CHANNEL 2 Frequency Response Full Bandwidth 50 kHz to 5 MHz gt 5 MHz to 10 MHz gt 10 MHz to 30 MHz Bandwidth Limit 50 kHz to 5 MHz Square Wave Flatness Field Rate 5 mV div to 10 mV div 20 mV div 50 mV div Line Rate 5 mV div to 10 mV div 20 mV div 50 mV div TV Back Porch Clamp CH 2 only 60 Hz Attenuation Back Porch Reference For VOLTS DIV switch settings be
19. d The LINES LED is illuminated and AUTO trigger mode is automatically selected Controls and Indicators 2445 2465 Option 05 Operators READOUT DISPLAYS In addition to the readout displays for oscilloscope opera tion shown in Sections 3 and 6 in the oscilloscope Oper ators manual an instrument equipped with the TV Option will display option status information when in any of the TV modes Also see the Operating Considerations section of this manual for additional information The crt readout will display TV Trigger information when the Trigger COUPLING switch is set to any of the TV trigger modes FLD 1 FLD 2 ALT or LINES or when the TV back porch clamp is active The TV Option utilizes a dis play area of up to 12 characters that are normally located in the right half of the top display line of the crt readout If the right half is not available the TV Option information is dis played in the left half of the top line When field triggering is selected the readout displays the line number selected for triggering the oscilloscope The line number readout is followed by a delta 4 symbol if the FLD LINE control is controlling the line number selection If the A symbol is not present the FLD LINE control will not change the line number selection The crt readout displays the message TVC whenever the TV back porch clamp is active 2 3 Section 3 2445 2465 Option 05 Operators PREPARATION FOR USE This section
20. g reaches the maximum number of lines in a field and either FLD 1 or FLD 2 coupling is selected additional clockwise turning of the control changes the line number to the beginning of the following field If alternate FLD 1 FLD 2 cou pling ALT is selected further rotation of the control past the maximum number will only reset the count to 1 When the line number setting reaches 1 and either FLD 1 or FLD 2 coupling is selected counterclock wise rotation of the control will move the line number to the maximum line number of the previous field If ALT coupling is selected the line number will move to the maximum line number common to both fields See the Line Number Format Selection discussion in the Preparation for Use section of this manual to choose the desired line number format See the example below for operation with a 525 line inter laced scan signal Format 1 12 263 112 2621 Format 2 1 2 263 1264 525l Field 1 2 FLD LINE Control Rotation CCW CW TRIGGER COUPLING Switch and Indicators Selects and indicates one of four addi tional choices for trigger coupling They are FLD 1 field 1 FLD 2 field 2 ALT alternate field 1 field 2 and LINES horizontal TV line sync triggering The crt readout will display the trigger coupling mode FLD 1 Sweep is triggered on the first field of the input TV signal and the FLD 1 LED is illuminated NORM trigger mode is automa
21. played signals c Adjust the INTENSITY and READOUT INTENSITY controls for desired display and readout brightness and best trace definition d Adjust the Vertical and Horizontal POSITION controls to position the trace within the graticule area Signal Input Coupling This procedure demonstrates the appearance of a video signal with the different positions of the CH 2 Input Coupling switch see Figure 5 1 Figure 5 1 Appearance of video signal with CH 2 Input Coupling switch positions 5 1 Basic Applications 2445 2465 Option 05 Operators a Connect a composite video signal to the CH 2 input connector and change the CH 2 input Coupling switch to DC b Obtain a stable baseline trace c With the CH 2 Input Coupling switch in 1 MQ DC note that the signal edges are flat d Set the CH 2 Input Coupling switch to 1 MQ AC and note the tilt in the waveform due to the input coupling capacitance e Set the CH 2 Input Coupling switch to TV CLAMP Notice that the waveform no longer has tilt and has returned to a dc coupled appearance Time Interval Measurements This procedure demonstrates how to use the At cursors to make timing measurements on the video waveform a Set the TRIGGER COUPLING switch to the LINES position and the A AND B SEC DIV switches to 10 us b Push in the At button c Use the 4 REF OR DLY control to position one cursor on the rising edge of the first sync pulse and use the A control to posi
22. re unless it has been specifically certified for such operation Do Not Remove Covers or Panels To avoid personal injury do not remove the product covers or panels Do not operate product without the covers and panels properly installed 2445 2465 Option 05 Operators The 2445 Option 05 TV Oscilloscope The 2465 Option 05 TV Oscilloscope Section 1 2445 2465 Option 05 Operators SPECIFICATION INTRODUCTION The TEKTRONIX 2445 and 2465 Oscilloscopes with Op tion 05 TV Option have additional hardware and software features to simplify triggering and viewing of television sig nals The option adds TV back porch clamp circuitry to the Channel 2 input and TV trigger coupling modes are pro vided allowing a user to select either horizontal or vertical sync pulses to obtain horizontal line sync or field sync pulse triggering This option permits the user to trigger on a spe cific line number within a TV field and provides sync polarity switching for either sync negative or sync positive compos ite video signals NOTE Composite video is the picture waveform complete with vertical and horizontal blanking and sync Com posite sync is combined vertical and horizontal sync as a single waveform but without video picture waveforms Both system M and nonsystem M protocols are avail able providing compatibility with most television signal line numbering protocols Stable video rejection and sync separation is o
23. reset the line counter Format 1 Query returns Line count reset status either LCNTR F10 or LCNTR BOT See the GPIB Option manual system commands for details The string returned for the TV Option is TV FVz where z is the version number Section 5 2445 2465 Option 05 Operators BASIC APPLICATIONS The basic instrument with the TV Option provides an ac curate and flexible measurement system for displaying and analyzing video information After becoming familiar with the controls indicators operating considerations and capabili ties of the instrument perform the following procedures to become familiar with the oscilloscope functions for making TV related measurements Before proceeding with these instructions refer to Preparation for Use Section 3 Verify that the POWER switch is OFF push button out then plug the power cord into the power outlet Initial Setup a Press in the POWER switch button ON b Set the instrument controls to obtain a baseline trace as follows Vertical CH 2 POSITION Midrange MODE CH 2 BW LIMIT Off button out CH 2 VOLTS DIV 0 2 V CH 2 VOLTS DIV VAR Calibrated detent CH 2 Input Coupling GND Horizontal A AND B SEC DIV Locked together at 5 ms SEC DIV VAR Calibrated detent POSITION Midrange X10 MAG Off button out Trigger HOLDOFF MIN fully ccw LEVEL Midrange MODE NORM SOURCE CH 2 COUPLING FLD 1 SLOPE for sync negative dis played signals and for sync positive dis
24. sition Front Panel Update When any front panel change is made and the TV back porch clamp is enabled the display may jump vertically However the TV back porch clamp will return the back porch level to its previous position CH 2 SIGNAL OUT Connector To preserve waveform fidelity of a video signal applied to the CH 2 Input Connector when the TV Clamp is enabled the CH 2 SIGNAL OUT connector on the instrument rear panel should be unterminated open If the connector is ter minated into 50 Q there may be a slight shift in the back porch level between adjacent lines of the video waveform IDENTIFYING FIELDS FRAMES AND LINES IN 525 60 AND 625 50 TV SYSTEMS NTSC CCIR System M Field 1 is defined as the field whose first equalizing pulse is one full H interval 63 5 us from the preceding horizontal sync pulse The field 1 picture starts with a full line of video and its lines are numbered 1 through 263 starting with the leading edge of the first equalizing pulse The first regular horizontal sync pulse after the second equalizing interval is the start of line 10 Field 2 starts with an equalizing pulse a half line interval from the preceding horizontal sync pulse The field 2 picture starts with a half line of video and its lines are numbered 1 through 262 starting with the leading edge of the second equalizing pulse After the second equalizing interval the first full line is line 9 CCIR System B and Similar 625
25. the TV Option installed all basic instrument functions as explained in the respective oscilloscope technical man uals remain unchanged FRONT PANEL CONTROL AND SETUP CONSIDERATIONS The following information is useful when using the oscil loscope in TV applications To operate properly observe the oscilloscope front panel controls and input signal considerations TV Clamp The TV back porch clamp is used to stabilize ac coupled TV waveforms and to remove tilt or hum present in the displayed TV waveform If the Channel 2 signal is not composite video or composite sync or the sweep is not trig gered on TV Sync TV back porch clamp operation is unpredictable If the TV back porch clamp is enabled with no TV sync applied to the trigger the CH 2 trace may drift vertically This is normal turning the TV back porch clamp off will restore normal operation Use the procedure below to identify the signal type of an input signal to the CH 2 input connector 1 Turn the TV back porch clamp off and select CH 2 TRIGGER COUPLING 2 Obtain a stable waveform using the desired TV trigger mode 3 Determine whether the displayed signal is composite video or composite sync 4 lf necessary turn the TV back porch clamp on A FLD LINE Control The A FLD LINE control is used for selecting a specific TV line within a field as well as positioning the A cursor When it can be used for line number selection a delta A
26. tically selected Controls and Indicators 2445 2465 Option 05 Operators POSITION QP POSITION POSITION MODE G1 CH2 CH3 Q4 DO O 20MHz ADO INVERT CHOP BW LIMIT PApastt dHu8N 4tT 1 VOLTS DIV VOLTS DIV A and B SEC Q POSITION XOLTS DIV POSITION i Q n1 O OUT AW CALIBRATOR N 5H 5MHz CH IMQ 15pF lt 400V pk COMP PROBE Im IMQ 15pF lt 400V pk AY a NTO INTO W 50Q A HUQ zv AMS Figure 2 1 TV Option front panel controls FLD 2 Sweep is triggered on the second field of the input TV signal and the FLD 2 LED is illumi nated NORM trigger mode is automatically selected ALT Sweep is alternately triggered by the two TV fields and both the FLD 1 and FLD 2 LEDs are illuminated NORM trigger mode is automatically selected When CHOP Vertical Mode is selected all of the active channels are triggered alternately by field 1 and field 2 of the video signal The two fields will appear overlayed When ALT Vertical Mode is selected and more than one channel is displayed field 1 of the video signal will trigger the first active channel and field 2 will trigger the next active channel When more than two channels are displayed each additional channel will be triggered first by field 1 and then by field 2 of the video trigger signal and its two fields will be overlayed LINES Sweep will trigger when the holdoff time has elapsed and a TV horizontal line sync pulse is encountere
27. tion the other cursor on the rising edge of the next sync pulse The line interval period can now be read directly from the upper right corner of the crt readout On a 525 line 60 Hz interlaced system the readout should be ap proximately 63 4 us A 625 line 50 Hz interlaced system should produce a readout of approximately 64 0 us d Push in both the V and At buttons simultaneously to get the 1 At function The crt readout now contains the line interval frequency On a 525 line 60 Hz interlaced system the readout should be approximately 15 8 kHz A 625 line 50 Hz system should produce a readout of approxi mately 15 6 kHz The preceding procedure measured line intervals on those random lines of the video signal which triggered the oscilloscope sweep To make a time interval measurement for a particular line within a field 5 2 e Set the TRIGGER COUPLING switch to either FLD 1 or FLD 2 depending on which field the desired line is in The INTENSITY control may have to be adjusted to increase the trace brightness f Adjust the FLD LINE control until the desired line number appears in the crt readout Specific time measure ments on that particular line can now be made This procedure may also be used to measure the width of a sync pulse g Set the CH 2 VOLTS DIV VAR and POSITION con trols so that the sync pulse exactly fills the screen between the 096 and 10096 graticule lines Enable the At function push in the X10 MAG b
28. tween 5 mV and 0 2 V div with VAR control in calibrated detent Five division 50 kHz reference signal from a 50 Q system With external 50 Q termination on 1 MQ input Within 196 Within 4 196 296 Within 4 296 396 Within 4 196 496 With fast rise step rise time lt 1 ns 1 MQ dc input coupling an external 50 termination and VAR VOLTS DIV control in calibrated detent Exclude the first 50 ns following the step transition For signals with rise times 10 ns add 296 p p between 155 ns and 165ns after step transition 1 5 p p at 60 Hz with input signal of 0 1 V 1 p p at 60 Hz with input signal of 0 1 V 1 p p at 60 Hz with input signal of 1 0 V 1 5 p p at 15 kHz with input signal of 0 1 V 196 p p at 15 kHz with input signal of 0 1 V 1 p p at 15 kHz with input signal of 1 0 V For VOLTS DIV switch settings between 5 mV and 0 2 V with VAR control in calibrated detent Six division reference signal 18 dB Within 1 0 division of ground reference REV MAY 1984 Specification 2445 2465 Option 05 Operators Table 1 1 cont Characteristics Performance Requirements Sync Separation Trigger Modes Main Sweep Delayed Sweep Input Signal Amplitude for Stabie Triggering Channel 1 or Channel 2 Composite Video Composite Sync Channel 3 or Channel 4 Composite Video Composite Sync TRIGGERING Stable video rejection and sync separation from sync positive or sync negative composite
29. utton and position the sync pulse on screen using the Horizontal POSITION control h Use the 4 REF OR DLY control to position one cursor at the 50 point of the leading edge of the sync pulse at the center horizontal gratiucle line and use the A control to position the other cursor at the 5096 point of the trailing edge of the sync pulse The sync pulse width can now be read directly from the upper right corner of the crt readout Voltage and IRE Measurements Voltage measurements can be made on the video signal using the AV cursors and the crt readout In addition IRE measurements expressed in percentages can also be made and displayed on the crt as a percent a Push in the AV button set the X10 MAG button out for X1 magnification and return the CH 2 VOLTS DIV VAR contro to its calibrated detent Waveform voltage measure ments can now be made by using the A REF OR DLY and A controls to position the AV cursors at the desired points of the video signal The crt readout will correspond to the volt age potential between the two points on the waveform b Set the CH 2 VOLTS DIV VAR and POSITION con trols so that the back porch and the top of a 100 modulated video signal exactly fill the screen between the 0 and 100 graticule lines c Any part of the waveform can now be measured in IRE units by using the A REF OR DLY and 4 controls to position the AV cursors at the appropriate positions of the waveform The crt readout will
30. video 525 to 1280 lines 50 Hz or 60 Hz interlaced or noninterlaced systems All lines Field 1 selected line 1 to n Field 2 selected line 1 to n Alt fields selected line 1 to n where n is equal to or less than the number of lines in the frame and less than or equal to 1280 Delayed by time Minimum for peak signal amplitude within 18 divisions of input ground reference 1 division 0 3 division Minimum for peak signal amplitude within 9 divisions of input ground reference 0 5 division 0 25 division Table 1 2 Option 05 Mechanical Characteristics Characteristics Weight With Power Cord Cover Pouch Probes Operators Manual and Options Domestic Shipping Weight Description 12 0 kg 26 4 Ib 17 6 kg 38 8 Ib 1 3 Section 2 2445 2465 Option 05 Operators CONTROLS AND INDICATORS FRONT PANEL CONTROLS Certain front panel controls on the oscilloscope have dual modes of operation when the TV Option is installed When the TV Option is enabled the controls have the func tions as described below When the TV Option is not en abled the controls have the functions described in the oscilloscope Operators manual and in other option Oper ators manuals if other options are installed See Figure 2 1 for the location of the TV Option front panel controls m CH 2 Input Coupling Switch Selects or deselects the TV back porch clamp function UP TV CLAMP Activates the TV
31. ymbol indicates where applicable cautionary or other information is to be found Protective ground earth terminal A ATTENTION Refer to manual Power Source This product is intended to operate from a power source that does not apply more than 250 volts rms between the supply conductors or 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 connecting 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 controls that may appear to be insulating 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 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 product in an explo sive atmosphe
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