Manual - TMG Test Equipment
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1. 36 Table 11 Logging menu parameters eene 36 Table 12 Control menu parameters eene 37 Table 13 Utility menus and parameters 37 Table 14 Measurements and calculations eese 41 Table 15 VARIABLE VALUE TDS COMMAND arguments and Queries I ER 44 Table 16 Measurement results queries o oooooooooooo oo 46 TDSCEMI Communication Eye Diagram Measurements Application User Manual a ae I Ii General Safety Summary Symbols and Terms A TDSCEM1 Communication Eye Diagram Measurements Application User Manual Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it To avoid potential hazards use this product only as specified Only qualified personnel should perform service procedures While using this product you may need to access other parts of the system Read the General Safety Summary in other system manuals for warnings and cautions related to operating the system Connect and Disconnect Properly Connect the probe output to the measurement instrument before connecting the probe to the circuit under test Disconnect the probe input and the probe ground from the circuit under test before disconnecting the probe from the measurement instrument Do not apply a potential to any terminal including the common terminal that exceeds the maximum rati2. E d P cross2 P base Figure 20 Eye diagram and mask pattern values P Values The P values include the mean and standard deviation of the vertical location of Ptop and Pbase These areas are used with a specified sample size to statistically measure the following values pTopMean the mean value of Ptop pTopSigma the standard deviation of Ptop pBaseMean the mean value of Pbase pBaseSigma the standard deviation of Pbase T1 Values The T1 values are vertical and horizontal values associated with the leftmost crossing point These areas are used to establish the following directions tCross1 Mean the horizontal mean of the left crossing point at Toros tCross1Sigma the horizontal standard deviation of the left crossing point at Teross1 tCross1PP the horizontal peak to peak deviation of the left crossing point at Teross1 pCross1Mean the vertical mean of the left crossing point at Peross1 40 TDSCEMI Communication Eye Diagram Measurements Application User Manual Appendix A Measurement Algorithms MaskHit Values T2 Values The T2 values are vertical and horizontal values associated with the rightmost crossing point These areas are used to establish the following directions m tCross2Mean the horizontal mean of the right crossing point at Teross2 m tCross2Sigma the horizontal standard deviation of the right crossing point at Teross2 W tCross2PP the horizontal peak to peak deviation of th
3. 0 0 Ean eect eens 36 Logemg Menu inte et ee IA C SU 36 Control Menu 6 6 56 A A ES BA Ro a LE HER 37 Utility Menu a A eG AR EE DUCUM 37 Appendix A Measurement Algorithms ooooooooo oo 39 Oscilloscope Setup Guidelines 39 Test Methodology aiii oe Ea bela ss a 39 Meastirements uses ea ur nn Gh ee net na nen 39 Appendix B GPIB Command Syntax cece cece eee 43 VARIABLE VALUE TDS COMMAND 000 eee eee eee nee 44 Description A ee hee OTRA RB 44 YMA Aa mes Ss oa E WEE e REN Ek BG ee dee 44 Arguments and Returns 0 cece eee eee nen eens 44 TDSCEMI Communication Eye Diagram Measurements Application User Manual Table of Contents List of Figures Figure 1 TDSCEM1 Communication Eye Diagram Measurements Application Eo I Y OPEP rn en Figure 2 Connecting to the SUT eeeeeeeeee Figure 3 Returning to the application eese Figure 4 Example of a mask pattern with an eye diagram the Results readout and a csv file datalog eee Figure 5 Starting the application eese Figure 6 TDSCEMI application initial display Figure 7 OC1 STMO standard mask pattern selected Figure 8 An OC1 STMO eye diagram and Results readout Figure 9 Measure menu page 1 eene Figure 10 Measure menu page2 oo oooooooooooooo oo Figure 11 Meas
4. Green is life ABN 43 064 478 842 Mm 231 osborne avenue clayton south vic 3169 PO box 1548 clayton south vic 3169 t 0392657400 f 03 9558 0875 J freecall 1800 680 680 www tmgtestequipment com au Test amp Complimentary Reference Material Measurement This PDF has been made available as a complimentary service for you to assist in e sales evaluating this model for your testing requirements e rentals TMG offers a wide range of test equipment solutions from renting short to long term buying refurbished and purchasing new Financing options such as Financial Rental and Leasing are also available on application calibration repair disposal TMG will assist if you are unsure whether this model will suit your requirements Call TMG if you need to organise repair and or calibrate your unit If you click on the Click to Call logo below you can all us for FREE TMG Corporate Website TMG Products Website e Leuel 4 Disposal Click to Call TMG Now Review amp Leuel5 Leuel 3 KGE Renew Review amp Renew epair a Se Level 2 e METE MK Calibration Recycled Leuel 1 e AMO Rcquisition e Purchase LU ff Lease Rent Solution Centre Product Lifecycle Management System Disclaimer All trademarks appearing within this PDF are trademarks of their respective owners NY E E v oW NAS Form 080 01 cM User Manual Tektronix Y TDSCEMI Communications Eye Diagram Measuremen
5. The required argu ments are listed in their proper order For example in the syntax definition PATH lt Ad gt lt Ars gt the arguments lt Ad gt and lt Ars gt are required in the order indicated Arguments The arguments to a command are defined along with their range of values Returns Defines the data returned in response to a command query Refer to the GPIB Program Example section for an example of a GPIB program that can execute the TDSCEM1 application NOTE Refer to the GPIB Program Example section for guidelines to use while designing your GPIB program TDSCEM1 Communication Eye Diagram Measurements Application User Manual 43 Appendix B GPIB Command Syntax VARIABLE VALUE TDS COMMAND Description Syntax Arguments and Returns VARIABLE VALUE TDS COMMAND accepts string arguments for a control or data variable and a value to which to set the argument VARIABLE VALUE VARTABLE VALUE lt variable name gt lt variable value gt the arguments lt variable name gt and lt variable value gt are required in the order indicated Table 15 lists the arguments their function and the query returns Table 15 VARIABLE VALUE TDS COMMAND arguments and queries Variable name Variable value Function Query form application Exit Terminates the active application Returns a string that corresponds to the name of the active application boxBackground Transparent Opaque Sets the m
6. follow these steps 1 Press SETUP gt Recall Factory Setup main gt OK Confirm Factory Init side to set the oscilloscope to the default factory settings 2 Press the VERTICAL MENU Ch 1 Coupling Impedance main DC side gt Q and select 50 3 Press WAVEFORM OFF as often as necessary to remove all waveforms from the display TDSCEMI Communication Eye Diagram Measurements Application User Manual 17 Tutorial Starting the Application 18 To perform these lessons the TDSCEMI application must be installed on the oscilloscope See Installation on page 3 To start the application follow these steps 1 Press SETUP gt Select Application main 2 Use the general purpose GP knob to select hd0 and press SELECT See Figure 5 Tek Run 100ks s Sample E A a EL Use to choose Press SELECT to change E E Select Directory hdo Free 162 3MH Application Td o hdo APP WEFMS TDSJIT1 APP TDSPSM 1 APP TDSDDMI APP TDSCEMT APP SEED YT a 99 05 06 Activate Application eca ave eca i Select File Saved Current Factory AWEHESEI TET Setup Setup Setup elite lites Utilities Figure 5 Starting the application 3 Use the GP knob to select the TDSCEM1 APP file and press Activate Application side The application starts up and displays as shown in Figure 6 TDSCEMI Communication Eye Diagram Measurements Appli
7. 2 L leaving the application 15 TDSCEM1 Communication Eye Diagram Measurements Application User Manual 47 Index lessons See tutorial lessons log file example 13 Logging menu 12 M main menus 5 Measure menu 9 Measure Options menu 10 measurements algorithms 41 application test method 39 descriptions 9 display results 11 example of viewing the results 13 GPIB program example 27 oscilloscope changes 11 parameters 35 selections 9 setting up 8 turning off display 14 tutorial lessons 17 menu Control 11 overview 33 menu structure description 5 detailed illustration 33 messages Warning 7 O Okay 6 online help 6 oscilloscope basic functions with the application 6 compatibility 1 setup guidelines 39 P parameters reference section 35 product compatibility 1 description 1 requirements and restrictions 2 updates 2 Q quitting the application 15 R readout turning off 14 Recall from File 15 Recall Setup 15 recalling a setup 14 requirements and restrictions 2 Results readout turning off 14 S Save Setup 14 Save to File 14 Save Recall Setup menu 14 setup default 15 recalling 15 saving 14 setup menus descriptions 10 side menus 5 Single acquisition mode 11 SONET document 8 Standard menu 8 starting application 18 T technical support viii Tektronix contacting viii terms vii tutorial lessons 17 saving the results
8. Fail Measure Control Options Ready Standard 001 Measure Utility Figure 14 Logging setup menu 2 To log the results to a csv file press Control main gt Start side The comma separated variable file format csv is compatible with many spreadsheet database or data analysis programs on a personal computer 3 After the measurement completes press Control main Start side to log more data to the results csv file Repeat this step two more times There are now four rows of data in the results csv file 4 To copy the results csv file to a floppy disk to view on a personal computer follow these steps a Insert a blank DOS formatted floppy disk into the floppy disk drive on the oscilloscope b Press SAVE RECALL SETUP gt File Utilities main 24 TDSCEM1 Communication Eye Diagram Measurements Application User Manual Tutorial Path to the csv file gt c Use the GP knob to highlight APP and press SELECT d Use the GP knob to highlight TDSCEM1 and press SELECT e Use the GP knob to highlight TEMP and press SELECT Figure 15 shows the RESULTS CSV file and the path to it Tek Run 20 0GS s ET Sampl E 0 hdo ao RESULTS CSV Use to choose 07 34 E Directory hd0 APP TDSCEMT TEMP Z P Figure 15 Path to the RESULTS CSV file Press SELECT to change 1 2 Free 162 2MEB File Utilit
9. OF THE POSSIBILITY OF SUCH DAMAGES AAA Table of Contents Related Documentation sisian irnad riaa a n aka ia vii GoOnventiOns xe a haben did te e eto i vii Contacting Tektronix asiri 42 sea cisn ir nete an whan ides viii Getting Started Product Description o oo oooooooooorororrrsr scr 1 Compatibility A SA LI at s 1 Requirements and Restrictions ooooocoocooccoccoocorcco eee 2 Updates Through a Web Browser 2 2 0 cece eee eee een eee 2 ACCEeSSOLIIES 02 Ania ns PRES PE Cee ET uui ea 2 Installation 5 2 seas ods onnu e nena ei an 3 Installing the Application 00 0c cect teen eens 3 Connecting to a System Under Test 0 00 c eee eee 4 Operating Basics Operating Basics sssi sesira ccc ccc ccc cc cece cece hmm 5 Application Menu Structure 0 cee eens 5 Main and Side Menus 0 cee ee eee ee eee eee ene 5 Common Menu Items 0 0 00 eee ee ee eee 6 Utility Menus 46 ere EN e DE NERA 6 Using Basic Oscilloscope Functions ooooococccooccocco eee 6 Using Local Help zc 2 ck E re X Ree EI epa ee ab 6 Returning to the Application 0 0 0 0 cece eee cee eee eee 7 Warning Messages 000 cece cece cette rn 7 Configuring the Display 00 0c c cece ene eens 7 Setting Up the Application 0 00 8 Standard Menu eoe eS ea EN E terea e 8 Measurement Setup 0 0 cece ec eee ene 9 Measurement Opti
10. RMS The RMS value of the edge jitter of the communication sgnal in seconds J itter 6Sigma The 6 sigma value of the edge jitter of the communication signal in seconds Jitter PP The peak to peak value of the edge jitter of the communication Crossing Signal in seconds The crossing point of the communication signal as a percentage of the height of the eye diagram Eye Height Eye Width Quality Factor The height of the communication signal in watts The height of the communication signal in seconds The ratio of the size of the communication signal to the noise on the signal P High The highest power level of the communication signal in watts P Low Ext Ratio Ext Ratio 96 The lowest power level of the communication signal in watts The ratio ofthe top of the communication signal to its base The ratio ofthe top of the communication signal to its base as a percentage Ext Ratio dB Duty Cycle Distortion sec The ratio ofthe top of the communication signal to its base in dBs Difference between the maximum and the minimum signal crossing times at 50 of the level TDSCEM1 Communication Eye Diagram Measurements Application User Manual 9 Operating Basics Measurement Options 10 Table 5 Measurements Cont Measurement name Description Duty Cycle Distortion Difference between the maximum and the minimum signal crossing times as a percentage of the bit period Mask Hits The numb
11. arguments and queries Cont Variable name Variable value Function Query form filterS tate Sets the state of the digital filter Returns the state of the digital filter jitter6S igmaS tate Sets the state of the jitter 6 Sigma Returns the state of the jitter 6 Sigma measurement measurement jitterP P State Sets the state of the jitter peak to peak Setthe state of the jitter peak to peak measurement measurement jitterR msS tate On Off Sets the state of the jitter RMS mea Returns the state of the jitter RMS surement measurement oggerDestination Sets the data log file name Returns the data log file name oggerState On Off Sets the state of the data log Returns the state of the data log maskS tandard None OC1 0C3 0C12 Sets the communications mask Returns the communications mask FC133 FC266 FC531 Standard Standard FC1063 ENET1250 maskState On Off Sets the state of the eye diagram Returns the state of the eye diagram measurement measurement pTopState Sets the state of the pTop measure Returns the state of the pTop measure ment ment pBaseState Sets the state of the pBase measure Returns the state of the pBase mea qualityF actorS tate On Off ment surement Sets the state of the quality Factor Returns the state of the quality Factor measurement measurement recallName Any string that uses one to Sets the recalled setup file name Returns the saved setup file name eight characters from A
12. can change display settings such as the message box location on the display Using Basic Oscilloscope Functions Using Local Help You can use the Utility menu to access help information about the application You can also use other oscilloscope functions and easily return to the application The application includes local help information about the measurements modes with some explanation of the individual controls To display the local help follow these steps 1 Press Utility main gt Help side 2 Use the side menu buttons to navigate through the help TDSCEMI Communication Eye Diagram Measurements Application User Manual Operating Basics Returning to the You can easily switch between the TDSCEMI application and other oscilloscope Application functions To access other oscilloscope functions press the desired front panel control To return to the application push the SHIFT and then the APPLICATION front panel menu buttons as shown in Figure 3 Push the SHIFT and then the APPLICATION button to return to the application SAVE RECALL WAVEFORM APPLICATION NSNU ACQUIRE MENU MEASURE CHARDCSPY RUN STOP gt SELECT UTILITY SHIFT CURSOR DISPLAY SHE ICV Figure 3 Returning to the application Warning Messages All eye diagram measurements provide a warning if the input conditions on channel 1 do not support accurate measurements For example the O
13. to Figure 2 and follow these steps the SUT before attaching a probe to it Do not touch exposed conductors except A WARNING To avoid electric shock you must ensure that power is removed from with the properly rated probe tips Refer to the probe manual for proper use 1 Power down the SUT 2 Connect the optical receiver probe to CH 1 of the oscilloscope 3 Press VERTICAL MENU Probe Functions main gt Cal Probe side This removes the dark level Pdark from the signal which allows the cursors to read the true signal power levels 4 Connect the optical receiver probe to a communication signal in the SUT TDS Oscilloscope CH1 SUT ex O OSO P6701B or P6703B OJE converter probe Optical cable Optical cable Optical attenuator Figure 2 Connecting to the SUT 4 TDSCEMI Communication Eye Diagram Measurements Application User Manual A d AAA Operating Basics AA a Operating Basics This section contains information on the following topics and tasks W Application menu structure m Using basic oscilloscope functions m Warning messages m Configuring the display m Setting up the application m Taking measurements m Storing the results to a data log file m Importing the data log file into a personal computer m Viewing the results m Saving and recalling setups m Exiting the application Application Menu Structure There are two types of menus in the application menu st
14. to Z and or zero to nine sampleS ize Any number from 32 to 32767 Sets the statistical sample size used to Returns the statistical sample size take measurements used to take measurements saveName Any string from one to eight Sets setup file name Returns the setup file name characters from A to Z and or zero to nine setup Default Recall Save Sets the setup file name Returns the setup file name sequencerMode FreeRun Single Sets the sequencer mode Returns the sequencer mode sequencerState Ready Paused Sequencing Sets the state of the sequencer Returns the state of the sequencer TDSCEM1 Communication Eye Diagram Measurements Application User Manual 45 Appendix B GPIB Command Syntax Table 16 lists the measurement results queries Table 16 Measurement results queries Variable name Function crossing Returns the crossing measurement dcd Returns the dcd measurement dcdP ercent Returns the dcd measurement error Returns an error message or returns if no error is detected extRatio Returns the extinction ratio measurement extRatioP Returns the extinction ratio measurement extRatioD Returns the extinction ratio dB measurement eyeHeight Returns the eye height measurement eyeWidth Returns the eye width measurement jitter6S igma Returns the jitter 6 Sigma measurement jitterP P Returns the jitter peak to peak measurement jitterRMS Returns the jitter RMS measurement mask Returns the mask measurement pHig
15. to a data log file 24 Statistics readout 21 taking a measurement 19 U Utility menu parameters 37 Utility menus 6 V viewing obscured parts of an eye diagram 13 W Warning messages 7 waveforms display color 8 web site 2 48 TDSCEMI Communication Eye Diagram Measurements Application User Manual
16. 0E 05 24 8182 4 029304 13 9476 1 10E 09 5 7024 0 3 2 04E 10 1 22E 09 1 15E 09 49 61538 2 24E 04 1 80E 08 21 66667 2 71E 04 1 10E 05 24 6364 4 059041 13 9157 1 05E 09 5 4432 0 4 1 95E 10 1 17E 09 1 05E 09 49 23664 2 23E 04 1 82E 08 20 15385 2 72E 04 1 00E 05 27 2 3 676471 14 3456 1 00E 00 5 184 0 Figure 17 Data in a Results csv file viewed in a spreadsheet program Stopping the Tutorial If you need more than one session to complete the tutorial lessons you can stop the tutorial and return to it another time To do so you will need to save the oscilloscope setup and then the application setup To save the oscilloscope setup refer to the user manual for your oscilloscope The procedure varies between models To save the application setup and stop your session refer to Saving a Setup on page 14 and to Exiting the Application on page 15 Returning to the Tutorial 26 To return to the tutorial setup you can recall the saved oscilloscope setup from the hard disk and then restart the application To recall the oscilloscope setup refer to the user manual for your oscilloscope The procedure varies between models To recall the application setup refer to Recalling a Setup on page 15 TDSCEMI Communication Eye Diagram Measurements Application User Manual A A GPIB Program Example This section contains an example of a GPIB program that can execute the TDSCEM1 application To execute the TDSCEM1 application with a GP
17. 3 STMI 155 52 Mb s m OC12 STM4 622 08 Mb s m FC133 Optical 132 8 Mb s m FC266 Optical 265 6 Mb s m FC531 Optical 531 2 Mb s m FC1063 Optical 1 0625 Gb s m Gigabit Ethernet Optical 1 25 Gb s Measure Menu Table 9 lists the parameters for the Measure menu the selections available and the default settings Table 9 Measure menu parameters Parameter Selections Default setting Jitter RMS On Off Off J itter 6Sigma On Off On Jitter PP On Off Off Crossing On Off On TDSCEMI Communication Eye Diagram Measurements Application User Manual 35 Parameters Reference Table 9 Measure menu parameters Cont Parameter Selections Default setting Eye Height On Off Off Eye Width On Off Off Quality Factor On Off Off P high On Off Off P low On Off Off Ext Ratio On Off Off Ext Ratio On Off Off ExtRatio dB On Off Off Duty Cycle Distortion sec On Off Off Duty Cycle Distortion On Off Off Mask Hits On Off Off Measure Options Menu Table 10 lists the parameters for the Measure Options menu the selections available and the default settings Table 10 Measure Options menu parameters Parameter Default setting Sample Size 32 to 32767 in increments of 1 256 Filter On Logging Menu Table 11 lists the parameters for the Logging menu the selections available and the default settings Table 11 Logging menu parameters Parameter Default setting On Off On Off Off St
18. 5 184 0 A csv file viewed in a spreadsheet program on a personal computer Figure 4 Example of a mask pattern with an eye diagram the Results readout and a csv file data log To view parts of the mask pattern and eye diagram that are obscured by the Results readout push the CLEAR MENU button To return to the application push the SHIFT then the APPLICATION front panel menu buttons NOTE To view the mask pattern eye diagram and the results you can change the configuration of the display through Utility main gt Display Options side TDSCEM1 Communication Eye Diagram Measurements Application User Manual 13 Operating Basics The next figure shows how to make the Results readout visible or invisible Main menu Side menu Side menu item Utility Display Options Dialog Box On Off NOTE The Results readout does not have to be visible to save measurements to a data log file The application can save the measurement results to a data log file while the oscilloscope displays the mask pattern and eye diagram and takes measurements Saving and Recalling Setups Saving a Setup 14 You can use the Save Recall Setup menu to save and recall application setups The TDSCEM1 application Save Recall function is totally independent of the primary oscilloscope Save Recall function stored in nonvolatile RAM The next figure shows how to access the Save Recall Setup menu Main menu Side menu
19. 531 Optical 531 2 Mb s FC1063 Optical 1 0625 Gb s Gigabit Ethernet Optical 1 25 Gb s Table 4 lists the mask pattern selections and the corresponding communication standard document to which each measurement complies Table 4 Mask pattern selections and communications standard documents Standard menu selection Communication standard document OC1 STMO 51 84 Mb s GR 253 CORE ISSUE 1 December 1994 Synchronous Optical Network SONET Transport OC3 STM1 155 52 Mb s Systems Common Generic Criteria Bellcore OC12 STM4 622 08 Mb s FC133 Optical 132 8 Mb s ANSI X3 230 1994 Fibre Channel Physical and Signaling Interface F C P H FC266 Optical 265 6 Mb s FC531 Optical 531 2 Mb s FC1063 Optical 1 0625 G b s Gigabit Ethernet Optical 1 25 Gb s ANSI IEEE 802 3 Fifth Edition 1996 Information Technology Telecommunications and Information Exchange Standard 8 TDSCEMI Communication Eye Diagram Measurements Application User Manual Operating Basics Measurement Setup The next figure shows how to access the measurement selections and Table 5 lists the TDSCEM1 measurements with a brief description of each Main menu Measure Side menu J itter RMS J itter 6Sigma Jitter PP Crossing Eye Height Eye Width Quality Factor P High P Low ExtRatio ExtRatio ExtRation dB Duty Cycle Distortion sec Duty Cycle Distortion Mask Hits Table 5 Measurements Measurement name Description Jitter
20. Application User Manual Getting Started A CA Product Description The TDSCEM1 Communication Eye Diagram Measurements Application is a Java based application that enhances basic capabilities of TDS oscilloscopes The application displays a mask pattern behind the eye diagram of the commu nication signal being acquired This allows you to visually analyze the eye dia gram against the mask pattern In addition the application can display other measurements in a numeric format as well as saving the information to a data log file to view on a personal computer Figure 1 shows an example of a standard mask pattern the eye diagram of an OCI STMO communications signal and the Results readout Tektronix TDS 784D irse ie olololiobo KO Figure 1 TDSCEM1 Communication Eye Diagram Measurements Application Compatibility The Communication Eye Diagram Measurements Application is compatible with the following Tektronix oscilloscopes m All TDS 500D and 700D Digital Phosphor Oscilloscopes with Option 2C Communications Signal Analyzer package and Option HD hard disk drive or Option 2M hard disk drive plus 8 MB record length the TDS oscilloscope must also have firmware version 6 4e and up m TDS 700C Color Digitizing Oscilloscopes with Option 2C Communica tions Signal Analyze
21. C12 standard mask selection warns you if the signal is outside the expected rate Configuring the Display You can change how dialog boxes appear on your oscilloscope as well as the color of waveforms The next figure shows how to access the Display Options menu and Table 3 lists the options with a brief description of each Main menu Side menu Side menu item Utility Display Options Dialog Box Box Position Box Style Color Theme Done Table 3 Display options Option Description Dialog box visibility Select Show or Hide to make dialog boxes visible or invisible Box position Select where on the display to position dialog boxes Left Middle or Right TDSCEM1 Communication Eye Diagram Measurements Application User Manual 7 Operating Basics Table 3 Display options Cont Option Description Box style Select the style of dialog boxes to be Opaque or Transparent Color Theme Select a set of colors for waveforms and dialog boxes The application offers seven color themes Setting Up the Application You can set up the application to take eye diagram measurements based on a standard mask pattern and to display the results or save them to a data log file Standard Menu The next figure shows how to access the standard mask pattern selections Main menu Side menu None OC1 STMO 51 84 Mb s OC3 STM1 155 52 Mb s 0C12 STM4 622 08 Mb s SA FC133 Optical 132 8 Mb s FC266 Optical 265 6 Mb s FC
22. IB program the program should comply with the following guidelines Turn on the GPIB response leaders with the HEADER OFF command refer to the programmer manual for your TDS oscilloscope The application startup must complete before sending additional GPIB commands to the application see example The measurements cycle must complete before data is queried see example The error variable should be checked to ensure that an error has not occurred because of a measurement command problem This example shows how a GPIB program might execute the application to do the following tasks m Start the application m Select a mask pattern m Enable a measurement m Set the sample size m Enable the logger m Take a measurement W Check for an error m Exit the application Refer to Appendix B GPIB Command Syntax for a complete list of the GPIB command syntax with the arguments variables and variable values TDSCEM1 Communication Eye Diagram Measurements Application User Manual 27 GPIB Program Example C Example Program TDSCEM1 GPIB control This sample program is for the Tektronix Java based TDSCEM1 Communication Eye Diagram Measurements Application include lt string h gt include lt stdio h gt include lt sys timeb h gt include lt windows h gt include C Program Files NationalInstruments GPIB NI1488 LangInt C decl 32 h int start_application in int scope int
23. Parameters Reference 38 TDSCEMI Communication Eye Diagram Measurements Application User Manual Appendices AS a as S Appendix A Measurement Algorithms The TDSCEM1 application displays a standard mask pattern behind the eye diagram of the communications signal being acquired The application can also take measurements from the eye diagram of a communication signal Oscilloscope Setup Guidelines For all measurements use the following guidelines to set up the oscilloscope 1 Always connect the communication signal to CH 1 2 The vertical scale for the communication signal must be set so that the eye diagram does not exceed the vertical range of the TDS oscilloscope 3 The input power level must be kept under 250 uW Test Methodology The application performs the measurement according to the following algorithm 1 Imports the eye diagram 2 Performs the measurement 3 Uses the results in the Results readout or saves the results to a data log file Measurements All eye diagram measurements are based on the power level the voltage level or the time locations of edges within each acquisition Mask patterns are defined in the Standard menu Figure 20 shows a mask pattern with an eye diagram and the areas from which values are taken that are used to calculate measurments TDSCEMI Communication Eye Diagram Measurements Application User Manual 39 Appendix A Measurement Algorithms Ur Pto p Teross1 Teross2
24. Side menu item Utility Save Recall Setup Recall Setup Recall from File Save Setup Save to File Done NOTE Press Utility main gt Save Recall Setup side to access the menu items that you can use to save and to recall setup files To save the application setup to the file displayed in the Save to File menu item press Save Setup side To create a new file in which to save the application setup follow these steps 1 Press Save to File side 2 Use the direction arrows and Delete Char side to clear the existing file name or part of the file name 3 Use the General Purpose GP knob to select each character in the file name Press Enter Char side after selecting each character The file name can be up to eight characters long TDSCEMI Communication Eye Diagram Measurements Application User Manual Operating Basics 4 Press OK Accept side to save the file name 5 Press Save Setup side to store the application setup in the file just created 6 Press Done side Application setups are always saved in the APPS TDSCEM1 TEMP directory accessed through the File Utilities menu on the oscilloscope Once you have saved a setup you must recall it to use it again Recalling a Setup To recall the application settings from the Default setup file or from a saved setup file follow these steps 1 Press Recall from File side until Default or the desired setup file name displays NOTE T
25. VERTICAL SCALE knob to set the Vert Attenuation to 20 50 or 100 uW per division or to a specific value between 20 uW and 100 uW The measurement results see Table 5 on page 9 display in a Results readout dialog box To view the mask pattern eye diagram and the results change the configuration of the Results readout through the Display Options side menu When the measurement parameters are set up you can acquire data from the communications signal To do so follow these steps 1 Press Control main Table 7 lists menu items in the Control menu Table 7 Control menu items Menu item Description Mode Single Performs measurements on a single acquisition and stops Free Run Repeatedly acquires the signal and takes measurements Start The application starts to take measurements from the signal Pause The application stops taking measurements and waits for a Continue Continue When paused the application continues taking measurements Stop The application stops taking measurements 2 Press Mode side to select Single or Free Run acquisition mode 3 Press Start side NOTE Do not change oscilloscope settings while a measurement is being taken Doing so can invalidate the measurement TDSCEM1 Communication Eye Diagram Measurements Application User Manual 11 Operating Basics Saving the Results to a Data Log File You can save the measurement results in a data log file The next figure shows the Logging setup menu
26. Variable value sequencerState status ibwrt scope write_buffer strlen write_buffer status ibrd scope read_buffer sizeof read_buffer read_buffer ibcnt 0 Get rid of extra characters Sleep 2000 while strcmp state read buffer 0 Though sequencerState Back to Ready need to check the error variable to make no error occur during measurement sprintf write buffer s Variable value error status ibwrt scope write buffer strlen write buffer status ibrd scope read buffer sizeof read buffer if ibcnt 3 error string is not empty read buffer ibcnt 0 Get rid of extra characters printf Error s n read buffer return 0 return 1 TDSCEM1 Communication Eye Diagram Measurements Application User Manual 31 GPIB Program Example 32 TDSCEMI Communication Eye Diagram Measurements Application User Manual CAS AAA A Reference AAA AAA Menu Structure Figure 18 shows the relationship of the application specific menus Main menu Side menus None OC1 STMO 51 84 Mb s OC3 STM1 155 52 Mb s 0C12 STM4 622 08 Mb s Stendal FC133 Optical 132 8 Mb s FC266 Optical 265 6 Mb s FC531 Optical 531 2 Mb s FC1063 Optical 1 0625 Gb s Gigabit Ethernet Optical 1 25 Gb s Jitter RMS Jitter 6Sigma J itter PP Crossing Eye Height Eye Width Quality Factor Measure P High P Low Ext Rat
27. and Table 8 lists the TDSCEM1 data log file selections with a brief description of each Main menu Side menu T On Off ogging Store Results In Clear Log File Table 8 Logging menu selections Data log file On Off Description Stores the measurement results in a csv file that you can view later ona personal computer Store Results In Allows you to name the csv file the extension must be csv Clear Log File Resets all result values to zero You must disable the log file before you can clear its contents Importing a Data Log File into a Personal Computer 12 You can import the data log file csv file into into a spreadsheet database or data analysis program on your personal computer for further analysis To do so follow these steps 1 Insert a blank DOS formatted floppy disk into the floppy disk drive of the oscilloscope Copy the csv file from the hd0 to the fd0 Refer to the Tutorial section Insert the floppy disk into the floppy disk drive on your personal computer Copy the csv file Uo me wd Open the file using a spreadsheet database or data analysis program The rows represent successful measurements The columns represent each type of measurement taken Figure 4 on the next page shows an example of the csv file viewed in a spreadsheet program on a personal computer TDSCEMI Communication Eye Diagram Measurements Application User Manual Operating Basics Viewing Data The appli
28. and read the Readme txt file before you continue If you are updating the application the Readme txt file on the Tektronix ftp site supercedes the Readme txt file on the TDSCEM1 floppy disk 2 Insert the disk in the floppy disk drive and power on the oscilloscope NOTE To verify that the TDS Run Time Environment V1 1 or above is installed watch for the name to appear at the top of the display when you power on the oscilloscope If it does not appear contact your local Tektronix sales office After performing the power up selftest the oscilloscope automatically begins the installation procedure As the application loads from the disk the oscilloscope displays a clock icon to indicate that it is busy Also the floppy disk drive LED is on indicating activity If the clock icon continues to display after the floppy disk LED has gone out a problem has occurred with the installation Repeat the above procedure If the problem persists contact your Tektronix representative When the installation is complete an Installation Complete message displays TDSCEM1 Communication Eye Diagram Measurements Application User Manual 3 Installation 3 Remove the floppy disk and cycle the power to the oscilloscope Connecting to a System Under Test You can use a P6701B or P6703B optical receiver probe to connect between your System Under Test SUT and the oscilloscope To connect the probe between the SUT and oscilloscope refer
29. cation User Manual Tutorial Tek Run 100kS s Sample j Standard None None j OCI STMO J 51 84 Mb s OC3 STM1 1155 52 Mb s OC12 STM4 622 08 Mb s M so0us Chi Eye Pattern Measurements Measure Logging control Utility Measure Options Ready Figure 6 TDSCEM1 application initial display Taking Measurements In this lesson you will learn how to use the TDSCEM1 application to take measurements from an eye diagram and its corresponding standard mask pattern To become familiar with communication eye diagram measurements follow these steps 1 Press Standard main gt OC1 STMO 51 84 Mb s side Figure 7 shows the Standard setup menu with the OC1 STMO mask pattern selected TDSCEM1 Communication Eye Diagram Measurements Application User Manual 19 Tutorial Tek Run 20 0GS s ET Sample d Standard i None None 7 OCI STMO J 51 84 Mb s 7 OC3 STM1 1133 52 Mb s OC12 5TM4 622 08 Mb s M2 50ns NRZ C 1 BR Eye Pattern Measurements Measure Logging Control Utility Measure Options Ready Figure 7 OC1 STMO standard mask pattern selected 2 Press CH 1 to display the OC1 STMO waveform 3 To take the measurement press Control main gt Start side The Control menu main displays Control Sequencing while the application is executing When the Control menu displays Control Ready the applica tion has completed the calcu
30. cation displays the selected mask pattern with the eye diagram of the communications signal for visual analysis and can display the results from selected measurements as numeric values in a Results readout You can also log the data to a csv file for viewing on a personal computer Figure 4 shows an example of the various ways to view the measurement data Mask pattern with eye diagram Results readout Jitter 6Sig 1 2768ns Jitter RMS 212 8ps Jitter PP 1 0999ns Crossing 48 473 Ext ratio 24 818 Ext ratio 4 02935 Ext ratio 13 947dB Eye height 214 00uW Eye width 18 051ns Quality Fact 16 375 P high 273 00uUW P low 11 0uW D cycle dist 1 0ns a j54mVo M2 50ns NRZ CHI D cycle dist 5 184 ita Mask Fails 0 0 Jitter Jitter Jitter Eye Eye Qual Ext Ext Ext D Cycle D Cycle Mask RMS 6Sig PP Crossing Height Width Fact P High PLow Ratio Rato RatiodB Distsec Dist Hits A B D E F G H J K L M N 0 1 1 95E 10 1 17E 09 1 05E 09 48 67925 2 23E 04 1 81E 08 18 92857 2 75E 04 1 00E 05 27 5 3 636364 14 3933 1 00E 09 5 184 0 2 2 12E 10 1 27E 09 1 10E 09 48 85496 2 23E 04 1 81E 08 20 15385 2 73E 04 1 10E 05 24 8182 4 029304 13 9476 1 1