WINDOWS CLIENT/SERVER

T1/E1 Analysis

Dynamic DSP Operations

Overview

Scripted DSP commands provide the ability to perform dynamic or time-varying operations via schedules. A schedule is a CSV file which specifies a sequence of digital signal processing steps to be performed at specified time offset for each operator on incoming and/or outgoing signals.

The Dynamic DSP Operation module allows real-time as well as offline testing using DSP commands to perform functions such as Amplification/Attenuation, Delay, and Filter.



Offline and Real-time Operations

Offline Dynamic DSP Operations

  • Amplify ("AmplifyDspOp" - dynamic amplification)
  • Attenuate ("AttenDspOp" - dynamic attenuation)
  • Delay ("DelayDspOp" - dynamic delay)
  • Filter ("FiltDspOp" - dynamic filter models)

Real-time Dynamic DSP Operations

  • Delay / Attenuate ("AttenDspOp" and "DelayDspOp")
  • Filter ("FiltDspOp")


Schedule (*.csv) Files

The dynamic capability can be most readily specified in a Schedules which are invoked through configuration (*.ini) files. Different instances of the same operator (the delay operator for example) can be scheduled by assigning a different identifier for each instance in a composite DSP operation.



Test Script Execution

Offline Operators

  • Attenuate DSP Operation


  • Example: The dynamic attenuate operation is implemented in WCS using the following script fragment:

    set latency 4;
    set response 6;
    outfile(atten(tone(642 hz, -10 dbm), 20 db), "WinClientServer\DynDspOp\ DynScaleDspOp.ala") 60 sec cfg "WinClientServer\DynDspOp\DynDspOp.ini";

    10 - 20 sec: Power = -26.21 dBov = -20.07 dBm.

    Target power is -10 dBm (source signal power) -10 dB (attenuation) = -20 dBm. Observe that power tapers down over transition interval of 1 second.

  • Delay DSP Operation


  • Example: The dynamic delay operation is implemented in WCS using the following script fragment:

    set latency 4;
    set response 6;
    outfile(delay(tone(1000 hz, -10 dbm), 10 msec), "WinClientServer\DynDspOp\ DynDelayDspOp.ala") 60 sec cfg "WinClientServer\DynDspOp\DynDspOp.ini";

    Between 20.0 and 21.0 sec., samples are repeated to insert more delay. Note the processing blocksize is 10 ms. For unclocked DSP operations (no tx or rx DSP operations), the processing block size is the sum of the latency and the response time.

  • Filter DSP Operation


  • Example: The dynamic filter operation is implemented in WCS using the following script fragment:

    set latency 4;
    set response 6;
    Dspop {outfile(filter(whitenoise(-10 dbm), "WinClientServer\DynDspOp\SOffice.xfr"), "WinClientServer\DynDspOp\DynFiltDspOpSin.ala"), outfile(whitenoise(-10 dbm), "WinClientServer\DynDspOp\DynFiltDspOpRin.ala") } 60 sec cfg "WinClientServer\ DynDspOp\DynDspOp.ini";

    This script produces two output files:

    DynFiltDspOpRin.ala: The original noise signal in A-Law compressed form.
    DynFiltDspOpSin.ala: The dynamically filtered noise signal in A-Law compressed form.

    0 - 10 sec: Power = -32.36 dBov = -26.21 dBm.

    Target power is -10 dBm (source signal power) -16.36 dB (SOffice.xfr attenuation) = -26.36 dBm



Real-time Operators

  • Real-Time Delay/Attenuate ("delay" and "atten" DSP Operations)
  • Real-time testing of the dynamic filtering capability is carried as depicted in the following diagram:

    Example: The dynamic echo path is implemented in WCS using the following script fragment:

    set latency 4;
    set response 6;
    tx(atten(delay(rx(#2:1), 10 msec), 5 db), #2:1) 60 sec cfg "WinClientServer\DynDspOp\ DynDspOp.ini" priority 1;



  • Real-Time Filter DSP Operation
  • Real-time testing of the dynamic filtering capability is carried as depicted in the following diagram:

    Example: The dynamic echo path is implemented in WCS using the following script fragment

    set latency 4;
    set response 6;
    tx(filter(rx(#2:1), " WinClientServer\DynDspOp\SOffice.xfr"), #2:1) 60 sec cfg "WinClientServer\DynDspOp\DynDspOp.ini" priority 1;

    The small, medium, and large office filters at 5 secs, 15 secs, and 25 secs as set in the schedule file is clearly visible in the DEC view pane.



Resources

Please Note: The XX in the Item No. refers to the hardware platform, listed at the bottom of the Buyer's Guide, which the software will be running on. Therefore, XX can either be ETA or EEA (Octal/Quad Boards), PTA or PEA (tProbe Units), UTA or UEA (USB Units), HUT or HUE (Universal Cards), and HDT or HDE (HD cards) depending upon the hardware.

Click here to download scripts for Dynamic DSP Offline and Real-time Operations with a help guide for Real-time Test Procedure.





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