Service Manuals, User Guides, Schematic Diagrams or docs for : Tektronix TEK CTS850 Test Set Reference 8A_jitwn

<< Back | Home

Most service manuals and schematics are PDF files, so You will need Adobre Acrobat Reader to view : Acrobat Download Some of the files are DjVu format. Readers and resources available here : DjVu Resources
For the compressed files, most common are zip and rar. Please, extract files with Your favorite compression software ( WinZip, WinRAR ... ) before viewing. If a document has multiple parts, You should download all, before extracting.
Good luck. Repair on Your own risk. Make sure You know what You are doing.




Image preview - the first page of the document
8A_jitwn


>> Download 8A_jitwn documenatation <<

Text preview - extract from the document
Setting Jitter/Wander Parameters

        This section gives examples of how to work with Jitter/Wander test
        setups; Setting Jitter or Wander Generation; Setting Jitter Receive
        Parameters; and, Calibrating Jitter Systems.
        Refer also to the Telecommunications Technology section within
        the Appendices (located on reference on CD)for theory of operation
        information on Jitter & Wander.
        CTS850 SDH/PDH Test Set


Jitter/Wander Working with Test Setups
        You can use the CTS850 to run the following types of jitter
        conformance tests:
        H Jitter Tolerance
        H Jitter Transfer
        H Output Jitter
        H Pointer Jitter (SDH rates only)
        In each of these tests, the CTS850 measures the jitter on a signal at
        the output of a network element. For some tests, the CTS850
        generates jitter to stimulate the network or a network element while
        it simultaneously measures the network response.




CTS850 SDH/PDH Test Set User Manual                                       3 159
Setting Jitter/Wander Parameters




         Figure 3 65:Example of TEST SETUP, Jitter & Wander screen


         Before selecting a jitter test, set the specific jitter generation and
         measurement rates and payloads required by the test. For example, to
         perform an output jitter test on an STM 1 signal, set the receive line
         rate to STM 1 before selecting test setups.
         It is not necessary to set the jitter and wander TRANSMIT or
         RECEIVE settings, since this is done automatically by the CTS850
         software, depnding on the test type.
         When the test is complete, you can save the results, print the results,
         or export the results data to bring into a spreadsheet. Refer to
         "Saving and Recalling Setups" later in this section for more
         information.

         Setting Up a Jitter Test
         To set up a jitter test:
         1. If the jitter test requires the test set to measure jitter, use the
            RECEIVE menu to set the receive parameters that are appropriate
            for the signal you will be measuring. Refer to Setting SDH
            Receive Parameters for information about this topic.




3 160                                  CTS850 SDH/PDH Test Set User Manual
                                               Setting Jitter/Wander Parameters




        2. If the jitter test requires the CTS850 to generate jitter, use the
           TRANSMIT menu to set the transmit parameters that are
           appropriate for the signal you will be generating. Refer to Setting
           SDH Transmit Parameters for information about this topic.
        3. To set the type of jitter test:


         Press Menu         Select Menu      Highlight
         Button             Page             Parameter         Select Choice
         TEST SETUPS        JITTER TESTS     Test Type         Output Jitter
                                                               Jitter Tolerance
                                                               Jitter Transfer
                                                               Pointer Jitter


            H Select Output Jitter to measure the jitter at the output of a
              network element. (The output jitter test does not use the
              CTS850 jitter-generation capability.)
            H Select Jitter Tolerance to measure the tolerance of the input
              of a network element to applied jitter (this test uses bit error
              measurement).
            H Select Jitter Transfer to measure the transfer of jitter from
              the input to the output of a network element.
            H Select Pointer Jitter to measure jitter in PDH signals due to
              pointer movement in the SDH signal (this test does not use
              jitter generation).
           The remaining parameters are dependent on the type of jitter test
           you select.




CTS850 SDH/PDH Test Set User Manual                                             3 161
Setting Jitter/Wander Parameters




         Jitter Tolerance Test. Follow these additional steps to set up a jitter
         tolerance test.
         1. Set the Test Type to Jitter Tolerance and set the mask type as
            appropriate. The available masks depend on the rate, as shown in
            the table below.


          Rate               Available Masks
          2 Mbit/s            G.823 (Standard), G.823 (National)
          34 Mbit/s           G.823
          45 Mbit/s *         G.824
          140 Mbit/s          G.823
          STM 0               GR 253
          STM 1               G.825, G.958 (Type A), G.958 (Type B)
          STM 4               G.825, G.958 (Type A), G.958 (Type B)



         * If your CTS 850 test set supports the 45 Mb/s option.
         The CTS850 modulates the transmitted line or clock frequency with
         sinusoidal jitter. The jitter generator begins at the start frequency and
         stops at the end frequency.
         2. To set the start frequency for the jitter generator:


          Press Menu        Select Menu         Highlight
          Button            Page                Parameter             Select Choice
          TEST SETUPS       JITTER TESTS        Start Frequency       as appropriate




3 162                                   CTS850 SDH/PDH Test Set User Manual
                                               Setting Jitter/Wander Parameters




        3. The available end frequencies are dependent on the current
           transmit rate. To set the end frequency for the jitter generator:


         Press Menu        Select Menu       Highlight
         Button            Page              Parameter            Select Choice
         TEST SETUPS       JITTER TESTS      End Frequency        as appropriate


        4. The CTS850 can generate jitter at intermediate frequencies
           between the start frequency and end frequency. To set the total
           number of frequencies generated (including the start and end
           frequencies):


         Press Menu        Select Menu       Highlight
         Button            Page              Parameter            Select Choice
         TEST SETUPS       JITTER TESTS      Number Freq          as appropriate *
                                             Samples


        * Number of samples change depending on Start/End frequencies.
        5. To set the tolerance criteria:


         Press Menu        Select Menu       Highlight
         Button            Page              Parameter            Select Choice
         Press Menu        Select Menu       Highlight
         Button            Page              Parameter            Select Choice
         TEST SETUPS       JITTER TESTS      Tolerance Criteria   Onset of Errors
                                                                  BER Penalty


           H Select Onset of Errors to define the tolerance as two Errored
             Seconds in a 30-second time interval.
           H Select BER Penalty to measure the amount of jitter that is
             equivalent to a 1 dB loss of signal power at the input of the
             network element (optical only).



CTS850 SDH/PDH Test Set User Manual                                           3 163
Setting Jitter/Wander Parameters




         6. If you selected Onset of Errors, skip to step 12. If you selected
            BER Penalty, continue with step 7 (see the following figure).




         Figure 3 66:Example of TEST SETUP, Jitter Tests, BER Method


         7. The CTS850 must be connected to a network element through an
            optical attenuator.
         8. To set a baseline bit-error rate for the measurement:


          Press Menu        Select Menu       Highlight
          Button            Page              Parameter         Select Choice
          TEST SETUPS       JITTER TESTS      Record Error      Measure BER
                                              Threshold


         9. Observe the Current BER and Recommended BER values in the
            display. Increase the optical attenuation until the Current BER
            reaches or exceeds the Recommended BER.




3 164                                 CTS850 SDH/PDH Test Set User Manual
                                                 Setting Jitter/Wander Parameters




        10. When the Current BER equals the Recommended BER to within
            an order of magnitude:


         Press Menu         Select Menu        Highlight
         Button             Page               Parameter          Select Choice
         TEST SETUPS        JITTER TESTS       Record Error       Record BER
                                               Threshold


        11. Increase the receive level by 1.0 dB (that is, reduce the
            attenuation by 1.0 dB).
        12. Press the START/STOP button to run the jitter test. The results
            are displayed on screen in numerical and graphical form. This
            takes about 6 minutes for 6 points.

        Transfer Jitter Test. Follow these additional steps to set up a jitter
        transfer test.
        1. Set Test Type to Jitter Transfer. Set the mask type as follows:


         Press Menu         Select Menu        Highlight
         Button             Page               Parameter          Select Choice
         TEST SETUPS        JITTER TESTS       Mask Type          as appropriate


        The available mask types are dependent on the current transmit rate.
        The CTS850 modulates the transmitted line with sinusoidal jitter. If
        the TX menu sets Jitter Output to Clock, the Jitter Transfer screen
        will indicate "Unsupported Settings". The jitter generator begins at
        the start frequency and stops at the end frequency.
        2. The available start frequencies are dependant on the current
           transmit rate. To set the start frequency for the jitter generator:


         Press Menu         Select Menu        Highlight
         Button             Page               Parameter          Select Choice
         TEST SETUPS        JITTER TESTS       Start Frequency    as appropriate



CTS850 SDH/PDH Test Set User Manual                                              3 165
Setting Jitter/Wander Parameters




         3. The available end frequencies are dependent on the current
            transmit rate. To set the end frequency for the jitter generator:


          Press Menu        Select Menu       Highlight
          Button            Page              Parameter          Select Choice
          TEST SETUPS       JITTER TESTS      End Frequency      as appropriate


         4. The CTS850 can generate jitter at intermediate frequencies
            between the start frequency and end frequency. To set the total
            number of frequencies generated (including the start and end
            frequencies):


          Press Menu        Select Menu       Highlight
          Button            Page              Parameter          Select Choice
          TEST SETUPS       JITTER TESTS      Number Freq        as appropriate *
                                              Samples


         * Points dependent on Start/End frequencies.


         NOTE. You can calibrate a 0 dB baseline, as described in ITU T
         O.171, prior to measuring transfer jitter if the folllowing conditions
         are met: the jitter generation output and measurement input are both
         set to line, and if the transmit and receive rates are set to the same
         rate. If either of the conditions can not be met, skip to step 10.

         5. Verify that the jitter generation output and measurement input are
            both set to Line.
         6. Verify that the transmit and receive rates are set to the same rate.




3 166                                  CTS850 SDH/PDH Test Set User Manual
                                                Setting Jitter/Wander Parameters




        7. To calibrate a 0 dB baseline:


         Press Menu        Select Menu        Highlight
         Button            Page               Parameter          Select Choice
         TEST SETUPS       JITTER TESTS       Action             Calibrate


        8. Press the START/STOP button to run the 0 dB baseline
           calibration routine. This takes about 3 minutes.
        9. To run the transfer jitter test after the calibration is complete,
           press Edit Setup:


         Press Menu        Select Menu        Highlight
         Button            Page               Parameter          Select Choice
         TEST SETUPS       JITTER TESTS       Action             Jitter Transfer


        10. Press the START/STOP button to run the jitter transfer test. The
            results are displayed on screen in numerical and graphical form.
            This takes abouts 4 minutes for 7 samples. Press View Data to see
            the data and whether or not the test passed. Press Edit Setup to
            return to Main Jitter Test menu.




CTS850 SDH/PDH Test Set User Manual                                             3 167
Setting Jitter/Wander Parameters




         Output Jitter Test. Follow these steps to set up an output jitter test.
         1. Set Test Type to Output Jitter. The recommended time duration
            for an output jitter test is one minute. To set the test duration to
            one minute (or any other duration of your choice),:


          Press Menu         Select Menu        Highlight
          Button             Page               Parameter          Select Choice
          TEST SETUPS        JITTER TESTS       Test Duration      15 sec, 30 sec
                                                                   1 min, 15 min
                                                                   USER DEFINED


             H Select USER DEFINED to enter a time other than one of the
               preset choices. The maximum duration is 99 days, 23 hours,
               59 minutes, 59 seconds.
         2. Press the START/STOP button once or twice, light should be lit
            to run the jitter test. The results are displayed on screen in
            numerical form. After the test duration time has passed for each
            filter (wideband and highband), compare measured jitter with the
            maximum allowed to determine pass or fail. The resolution of
            these measurements are 0.001 UIpp.

         Pointer Jitter Test. Follow these additional steps to set up a pointer
         jitter test. To select Pointer Jitter, the TX must be set to a SDH rate,
         and the RX set to a PDH rate.
         1. Set Test Type to Pointer Jitter. To set the pointer sequence type:


          Press Menu         Select Menu        Highlight
          Button             Page               Parameter          Select Choice
          TEST SETUPS        JITTER TESTS       Sequence Type      as appropriate


         2. Press the START/STOP button to run the jitter test. The results
            are displayed on screen in numerical form, after about 6 minutes.




3 168                                   CTS850 SDH/PDH Test Set User Manual
                                                 Setting Jitter/Wander Parameters




        Saving and Recalling Results
        You can save one jitter test result to disk and recall that one test
        result for later display and analysis. If you want to save test results
        permanently, you must save the test results to a disk.
        The CTS850 saves each type of jitter test result with a unique
        file-name extension. Because of the unique extensions, you can
        perform different types of jitter tests on a network element and give
        them a common results file name.
        To save jitter test results:


         Press Menu         Select Menu        Highlight
         Button             Page               Parameter          Select Choice
         TEST SETUPS        JITTER TESTS       Test Control       Save Results


        Refer to Saving and Recalling Results for detailed information about
        using the disk drive to save and recall results.

        Printing Results
        You can print jitter test results using the "Print Last Screen" choice
        in the Print Control dialog box. Refer to Printing Results for detailed
        information about printing.

        Exporting Results into a Document
        You can export the jitter tolerance and jitter transfer test results in a
        Microsoft Excel compatible format to produce a graph for your
        documentation. Use the saved files with .XTL or .XTR for this
        purpose.
        The file format consists of a header that identifies the type of test,
        the date and time, the transmit source, the transmit and receive rates,
        and the number of sample points in the graph. Data following the
        header is comma separated and consists of four values for each
        sample point in the graph: modulation frequency, mask amplitude,
        measured amplitude, and a status indicator that indicates an
        over range condition.



CTS850 SDH/PDH Test Set User Manual                                           3 169
Setting Jitter/Wander Parameters




Setting Jitter or Wander Generation
         To test the response of a network to jitter, you may need to generate
         SDH signals, PDH signals, or clock signals that contain jitter. You
         can use the CTS850 to generate any of these signals with a
         controlled amount of jitter. This jitter is a sinusoidal modulation of
         the line rate or clock rate; you can specify the frequency and
         amplitude of the jitter.
         Wander generation selection is identical to jitter generation except
         that it applies for modulation frequencies of 10 Hz or less. See the
         following figure.




         Figure 3 67:Example of TRANSMIT, Jitter menu




3 170                                 CTS850 SDH/PDH Test Set User Manual
                                              Setting Jitter/Wander Parameters




        NOTE. The jitter compliance tests, available through the JITTER
        TESTS page of the TEST SETUPS menu, automatically set the jitter
        generation parameters needed for the test. When you use the jitter
        compliance tests, you do not need to set the controls described below.

        Periodic calibration of the jitter generation system is recommended
        to maintain best accuracy. You can execute a built in calibration
        routine before making critical measurements. Refer to the Jitter
        Calibration information located at the end of the this section.



        Turning on Jitter or Wander Generation
        To turn on jitter or wander generation:


         Press Menu       Select Menu       Highlight
         Button           Page              Parameter         Select Choice
         TRANSMIT         JITTER &          Jitter/Wander     Off
                          WANDER            Generation
                                                              On


        H Select Off to disable jitter/wander generation.
        H Select On to enable jitter/wander generation.




CTS850 SDH/PDH Test Set User Manual                                      3 171
Setting Jitter/Wander Parameters




         Selecting the Jitter Output
         To select the signal that you want to apply generated jitter to:


          Press Menu        Select Menu       Highlight
          Button            Page              Parameter           Select Choice
          TRANSMIT          JITTER &          Jitter Output       Line
                            WANDER
                                                                  Clock 0.8 V
                                                                  2 MHz G.703


         H Select Line to enable generated jitter on the transmitted line
           (SDH signal or PDH signal) that comes out of the front panel.
           This will also generate jitter on the rear-panel Jitter Clock
           Output, even though it may not be in use. Note: for 140 Mbit/s
           and STM 1E, line mode rear panel signal is twice the line rate.
         H Select Clock 0.8 V to enable generated jitter on the rear-panel
           jitter clock output (J/CLK OUT) only (AC-coupled ECL). The
           transmitted line remains jitter free.
         H Select 2 MHz G.703 to enable generated jitter on the rear-panel
           jitter clock output (J/CLK OUT) that meets the interface
           requirements for synchronization signals as specified in G.703.
           The transmitted SDH or PDH line signal remains jitter free.
         You can independently set the Jitter Clock Output rate and frequency
         offset, regardless of the line rate and frequency offset of the
         transmitted signal. To set an independent rate for the Jitter Clock
         Output:


          Press Menu        Select Menu       Highlight
          Button            Page              Parameter           Select Choice
          TRANSMIT          JITTER &          Jitter Output       Clock 0.8V
                            WANDER
                                              Jitter Clock Rate   as appropriate




3 172                                  CTS850 SDH/PDH Test Set User Manual
                                               Setting Jitter/Wander Parameters




        To set an independent frequency offset for the Jitter Clock Output:


         Press Menu        Select Menu       Highlight
         Button            Page              Parameter             Select Choice
         TRANSMIT          JITTER &          Jitter Output         Clock 0.8V
                           WANDER
                                             Jitter Clock Offset   as appropriate


        Setting the Jitter Frequency and Amplitude
        The generated jitter is a sinusoidal modulation of the nominal line or
        clock rate. Refer to the Modulation Range specifications for details
        about jitter/wander generation capability. To set the modulation
        frequency:


         Press Menu        Select Menu       Highlight
         Button            Page              Parameter             Select Choice
         TRANSMIT          JITTER &          Jitter Frequency      as appropriate
                           WANDER


        H Select USER DEFINED to specify a jitter frequency different
          from the predefined choices. Use these choices: Course to
          adjust most significant digit or change decade scale; Medium to
          adjust second digit; Fine to adjust third digit.

        NOTE. To generate jitter, set the Jitter Frequency to 10 Hz or greater.
        To generate wander, set the Jitter Frequency to less than 10 Hz.




CTS850 SDH/PDH Test Set User Manual                                             3 173
Setting Jitter/Wander Parameters




         To set the modulation amplitude (in unit intervals):


          Press Menu        Select Menu       Highlight
          Button            Page              Parameter          Select Choice
          TRANSMIT          JITTER &          Jitter Amplitude   300.00 UI (Max)
                            WANDER                               150.00 UI (Max/2)
                                                                 0.0 UI


         H Select USER DEFINED to specify a jitter amplitude different
           from the predefined choices. Use choices Coarse, Medium or
           Fine.

         Measure Wander on a 2 MHz clock output from a network element
         When generating wander, synchronize the test system to an external
         timing source. This can be done by connecting a 2.048 MHz clck to
         the rear panel reference timing input and selecting timing source
         under TRANSMIT settings. Follow the steps below:
         H Connect 2 MHz reference clock to 2 Mbps/ 2 MHz reference
           clock input on Rear Panel of test unit.
         H Connect External 2 MHz clock to be measured to Jitter/ Clock
           input on Rear Panel of test unit.
         H Go to TRANSMIT settings. Set the Transmit Clock to 2 MHz
           external. The Receive Clock is the Same. No Wander Measure-
           ments should be made with Internal Clock.
         H Press Start/Stop twice to Start/Restart the test.
         H For RESULTS, select the Jitter & Wander Screen, and view
           Wander Measurements.




3 174                                  CTS850 SDH/PDH Test Set User Manual
                                              Setting Jitter/Wander Parameters




Setting Jitter Receive Parameters
        You can set the CTS850 to measure jitter or wander on incoming
        SDH signals, PDH signals, or clock signals. First, set the jitter
        receive parameters below. Then, you can view jitter or wander
        measurement results in the Jitter & Wander Results page shown at
        the end of this section on Jitter.




        Figure 3 68:RECEIVE, Setting Jitter Mode, Peak to Peak


        NOTE. The jitter compliance tests, available through the JITTER
        TESTS page of the TEST SETUPS menu, automatically set the jitter
        receive parameters needed for the test. When you use the jitter
        compliance tests, you do not need to set the controls described below.

        Periodic calibration of the jitter generation system is recommended
        to maintain best accuracy. You can execute a built in calibration
        routine before making critical measurements. Refer to the Jitter
        Calibration information located at the end of this section.




CTS850 SDH/PDH Test Set User Manual                                      3 175
Setting Jitter/Wander Parameters




         Selecting the Jitter Mode
         To select the jitter measurement mode:


          Press Menu        Select Menu       Highlight
          Button            Page              Parameter         Select Choice
          RECEIVE           JITTER &          Jitter Mode       Peak-Peak
                            WANDER
                                                                RMS


         H Select Peak-Peak to make peak-to-peak jitter measurements.
         H Select RMS to make RMS jitter measurements. If you select
           RMS, the only available input filter is a 12 kHz high-pass filter.

         Selecting the Input Source
         To select the input source on which you want to measure jitter:


          Press Menu        Select Menu       Highlight
          Button            Page              Parameter         Select Choice
          RECEIVE           JITTER &          Jitter Input      Line
                            WANDER            Source
                                                                Clock


         H Select Line to measure jitter in the received line (front-panel
           SDH or PDH signal) selected in the RECEIVE SETTINGS page.
         H Select Clock to measure jitter on the rear-panel external jitter
           clock input (J/CLK IN). If you select Clock, you must set the
           external jitter clock input rate; that rate does not have to be the
           same as the Receive Rate selected in the RECEIVE SETTINGS
           page.




3 176                                  CTS850 SDH/PDH Test Set User Manual
                                               Setting Jitter/Wander Parameters




        Selecting the Jitter Range
        The jitter range determines the maximum measureable jitter and the
        resolution of the measurement. To select the range:


         Press Menu         Select Menu      Highlight
         Button             Page             Parameter          Select Choice
         RECEIVE            JITTER &         Jitter Range       Normal
                            WANDER
                                                                Extended


        H Select Normal to measure jitter up to 6 UIp-p with a resolution of
          0.005 UI (frequency dependent). Refer to RX Range Mask in
          Specifictions section (in Appendix).
        H Select Extended to extend the jitter measurement range up to
          200 UIp-p (frequency dependent) with a resolution of 0.01 UI.

        Selecting the Jitter Input Filter
        You can choose from three types of jitter measurement high pass
        filters defined by ITU-T standards: wideband, highband, and
        fullband. The passbands for the filters, shown in Figure 3 69, are
        dependent on the signal or clock rate settings; the 3 dB frequencies
        are described in the Specifications located in the Appendices at the
        back of this book.
        The ITU T standard that applies to jitter input filters is contained in
        G.823, Table 1, Measurement Filter Bandwidth.




CTS850 SDH/PDH Test Set User Manual                                        3 177
Setting Jitter/Wander Parameters




                                     Fullband           Wideband      Highband




          Amplitude




                                                Frequency


         Figure 3 69:Jitter High PassFilters


         To select the jitter input filter:


          Press Menu      Select          Highlight
          Button          Menu Page       Parameter                Select Choice
          RECEIVE         JITTER &        Jitter Measurement       Wideband
                          WANDER          Filter
                                                                   Highband
                                                                   Fullband


         H Select Wideband to measure jitter using the wideband measure-
           ment filter (500 Hz 1.3 MHz).
         H Select Highband to measure jitter using the highband measure-
           ment filter (65 kHz 1.3 MHz).
         H Select Fullband to measure jitter over the wideband range plus
           very low frequency jitter that may affect timing quality for Video,
           PBX and GSM systems that derive an internal reference from the
           supplied line signal (10 Hz 1.3 MHz).




3 178                                    CTS850 SDH/PDH Test Set User Manual
                                                Setting Jitter/Wander Parameters




        NOTE. Separate Highband National and Highband Standard settings
        are available for the 2 Mb/s rate, as referenced in the ITU T
        standards.

        If you select the Fullband jitter input filter, perform the following
        steps to set the filter high-pass frequency:


         Press Menu        Select Menu        Highlight
         Button            Page               Parameter          Select Choice
         RECEIVE           JITTER &           Fullband           0.1 Hz
                           WANDER             High-pass
                                                                 1 Hz
                                                                 10 Hz


        Note that the lock time for 1 Hz and 10Hz settings are longer than
        other filter settings.

        Setting the Jitter Hit Threshold
        The jitter hit threshold determines the sensitivity of the Jitter Hit
        Seconds measurement, which is based on peak-to-peak jitter.
        Jitter Hit Seconds is a count of how many seconds the threshold was
        exceeded since the beginning of the the measurement. Measurement
        will normally begin between 2 5 seconds after the start button on the
        front panel is pressed. You can set the threshold to any value between
        0 and 200 UI, depending on the Range Setting.
        Whenever the received jitter exceeds the range of the jitter
        measurement system, the Current Jitter reads Unlocked. Jitter
        Unlocked Seconds is a count of how many seconds the measurement
        system has been unlocked since the beginning of the the measure-
        ment.




CTS850 SDH/PDH Test Set User Manual                                             3 179
Setting Jitter/Wander Parameters




         To set the jitter hit threshold:


          Press Menu         Select Menu          Highlight
          Button             Page                 Parameter      Select Choice
          RECEIVE            JITTER &             Jitter Hit     as appropriate
                             WANDER               Threshold


         H Select USER DEFINED to specify a jitter hit threshold different
           from the predefined choices.

         Setting the Pointer Hit Threshold
         The pointer event threshold (available for PDH rates) determines the
         sensitivity of the Jitter Pointer Hits measurement, which is based on
         the frequency drift rate. To set the pointer event threshold:


          Press Menu         Select Menu          Highlight
          Button             Page                 Parameter      Select Choice
          RECEIVE            JITTER &             Pointer Hit    as appropriate
                             WANDER               Threshold


         H Select USER DEFINED to specify a pointer hit threshold
           different from the predefined choices. You can set the threshold
           to any value between 0 and 10 ppm/sec.




3 180                                       CTS850 SDH/PDH Test Set User Manual
                                             Setting Jitter/Wander Parameters




        Example of Jitter Measurements
        The RESULTS screen for Jitter/ Timing Quality follows.




        Figure 3 70:RESULTS, Jitter and Timing Quality




CTS850 SDH/PDH Test Set User Manual                                    3 181
Setting Jitter/Wander Parameters




         Example of Wander Measurements
         The "max" value shows the maximum peak to peak,positive peak,
         and negative peak since the beginning of the measurement.
         When measuring wander, it is necessary to synchronize the test to an
         external timing source. This can be done by connecting a 2.048 MHz
         clock signal to the rear panel timing input and selecting the
         appropriate timing source under the TRANSMIT settings.
         The RESULTS screen for Wander/ Line Frequency follows.




         Figure 3 71:RESULTS, Wander and Line Frequency




3 182                                CTS850 SDH/PDH Test Set User Manual
                                              Setting Jitter/Wander Parameters




Calibrating Jitter Systems
        Periodic calibration of the jitter generation and measurement systems
        is recommended to maintain best accuracy. You can execute built in
        Jitter Measurement calibration routines before making critical
        measurements.
        Run Jitter Measurement before runing Jitter Generation Calibration.
        This Jitter Measurement calibration takes about 15 minutes for all
        rates. You can calibrate one particular rate by selecting the
        appropriate calibration routine.
        If your CTS 850 test set supports a 45 Mb/s rate, this screen below
        will show that rate in addition to all the others displayed.




        Figure 3 72:Example of UTILITY, Jitter Calibration




CTS850 SDH/PDH Test Set User Manual                                      3 183
Setting Jitter/Wander Parameters




         Executing Jitter Calibration
         To calibrate the jitter measurement system:


          Press Menu        Select Menu       Highlight
          Button            Page              Parameter          Select Choice
          UTILITY           CALIBRATION       System             Jitter
                                                                 Measurement
                                              Routine            All
                                              Calibration        Run
                                              Control


         To calibrate the jitter generation system:


          Press Menu        Select Menu       Highlight
          Button            Page              Parameter          Select Choice
          UTILITY           CALIBRATION       System             Jitter Generation
                                              Routine            All
                                                                 STM 0
                                                                 STM 1
                                                                 STM 4
                                                                 2 Mb/s
                                                                 34 Mb/s
                                                                 45 Mb/s
                                                                 140 Mb/s
                                                                 Analog output
                                              Calibration        Run
                                              Control


         Jitter Generation for all rates takes about 45 minutes to run.
         A status message indicates that the calibration is running, has
         completed and has passed, or has failed.




3 184                                   CTS850 SDH/PDH Test Set User Manual



◦ Jabse Service Manual Search 2024 ◦ Jabse PravopisonTap.bg ◦ Other service manual resources online : FixyaeServiceinfo