T1 E1 Testing

Delay/Attenuate - Single Channel


Delay/Attenuate Timeslots - Single Channel Application is an addition to the already existing Echo Test Solutions suite of applications. This application also facilitates Low Delay Echo Path Modeling and applying delay, attenuation (gain), and/or filtering to a received signal on a single timeslot. You may also mix-in additional signals from other sources, including speech signals inserted via VF input. Speech signals inserted via VF input and Gaussian noise signals or Tone generated internally within the application.

Delay/Attenuate Timeslots - Single Channel Application

Main Features:

  • Transmission of data, voice or file on single timeslot
  • Multiple instances of the application can be opened simultaneously
  • The application can be implemented in firmware/hardware. This enhancement in the implementation enables to have a very low delay in the processed signal compared to the existing software based implementation
  • This application can receive and transmit on only one of the boards. Launching multiple instances of this window to work on a second card is allowed and recommended

Operating Configurations

  • Low delay (Real-time) echo-path simulation:

    This application is implemented in firmware/hardware, to support real-time echo path modeling. The key aspect is, the application overhead delay is within one sample or 1.25 milliseconds. It can also simulate all G.168 echo-path models.
  • Looping back a processed signal:

    Applying delay, attenuation, and/or filtering to a received signal and retransmitting the processed signal on to the same receiving board Speech and/or noise may also be mixed in. The following diagram illustrates this configuration.
  • Looping back a processed signal

  • Applying pure delay to a signal: A received signal is delayed before being retransmitted. This configuration is illustrated in the figure below.
  • Applying pure delay to a signal


This section describes the operation of the controls in Delay/Attenuate - Single Timeslot Application.

Delay/Attenuate - Single Timeslot

  • Card, Timeslot, Encoding selection

    The user can select the Rx and Tx timeslots differently. In this application the receiving and transmitting cards must be the same. You can select the transmit timeslot different from the receive timeslot
  • Card, Timeslot, Encoding selection

    Transmit encoding can be selected as A-Law, u-Law or none. If no decoding (None) is selected on the receive signal, the encoding will also become none.

    The "Capture To Receive Buffer" toggle control will enable to capture the transmitted data to the receive buffer, which can be viewed using "Power Spectral" screen.

    Capture To Receive Buffer

  • Processing the received signal data

    The following are the steps to process a received signal:
  • Processing the received signal data

    • Select the card and timeslot using the card and timeslot controls
    • Delay - Select a Delay value, appropriate for your testing. You can either type in a value or use the slider control to arrive at a specific value within the allowed range. The precision for Delay value is 0.125 milliseconds
    • Decoding - Select a decoding scheme (A-Law, u-Law or None). If either A-Law or u-Law is selected you can specify the Gain value as well as the filter
    • Gain - Select or enter a Gain value, which can have a granularity of 0.1 dB
    • Filter - Select a filter type and signal type. The filter type can be M1 to M8 and the signal type can be 1 (CSS) or 2 (Tone). All together you can have 16 combinations of filter selection

  • Filter and the Signal type as per ITU Specifications

    Given below are the ITU specifications corresponding to the Filter type and the Signal type (CSS/Tone) selections.
  • SL.No Filter Type CSS/Tone Scaling Factor Minimum ERL for CSS/Tones (dB)
    1 M1 1 (CSS) 1.39 x 10-5 6
    2 M1 2 (Tone) 1.22 x 10-5 6
    3 M2 1 (CSS) 1.44 x 10-5 6.55
    4 M2 2 (Tone) 6.78 x 10-6 6
    5 M3 1 (CSS) 1.52 x 10-5 6
    6 M3 2 (Tone) 9.66 x 10-6 6
    7 M4 1 (CSS) 1.77 x 10-5 6
    8 M4 2 (Tone) 1.07 x 10-5 6
    9 M5 1 (CSS) 9.33 x 10-6 6
    10 M5 2 (Tone) 7.05 x 10-6 6
    11 M6 1 (CSS) 1.51 x 10-5 6
    12 M6 2 (Tone) 8.60 x 10-6 6
    13 M7 1 (CSS) 2.33 x 10-5 11.06
    14 M7 2 (Tone) 6.58 x 10-6 6
    15 M8 1 (CSS) 1.33 x 10-5 9.27
    16 M8 2 (Tone) 4.58 x 10-6 6

  • Adding Speech from VF Input

    You can add speech using VF input, and then transmit it through the transmit timeslot. You can also mix the VF input with the processed received signal and then transmit it
  • The timeslot selected on the VF toolbar is not relevant as far as this application is concerned. For example if the transmit timeslot for this application is selected to be 2 and the VF input timeslot is selected as 5 then, on the transmitted T1/E1 signal, the timeslots 2 and 5 will contain the inserted VF signal. Depending on the other settings on this application, the transmitted signal on timeslot 2 will be summations of the processed receive signal and (or) the application data.

    Adding Speech from VF Input

  • Adding Application Data

    You can add the internally generated application data to the transmitted timeslot. Once you select the transmit timeslot, any internally generated data such as Tone, Gaussian noise etc on that particular timeslot will be added to the transmitted signal.

    Intrusive Test > Transmit Tone or Intrusive Test > Transmit Gaussian Noise applications can be used to internally generate a signal, which will be transmitted on the same timeslot as in Delay Attenuation application.
  • Adding Application Data

    Once the configuration is complete, you can start the processing. Additionally if the graphical view is visible, it will show an animated display of the flow of data from the various input points to the output (transmit) point.

    Application configuration


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. 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.

Item No. Item Description
XX062 Echo Path Delay/Loss Simulation (Delay Attenuate Timeslots) Software
(Not supported in T1E1 Quad and Octal boards)
  Related Software
XX020 File Record/Playback Software
XX051 Synchronous Trunk Record Playback
XX022 Dial DTMF/MF Digits Software (optional)
XX031 Enhanced T1 / E1 Call Capture/Analysis Software (optional)
XX063 Echo Path Delay/Loss Measurement Software
XX065 G.168 Echo Canceller Test Suite
XX066 Digital Echo Canceller
XX067 Automated Echo Canceller Testing with or without VQT
XX068 Semi-automated Scripted EC Testing
  Related Hardware
HDT001/HDE001 Legacy HD T1 or E1 (PCI) Cards with Basic Analyzer Software
UTE001 Portable USB based Dual T1 or E1 Laptop Analyzer