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Portable USB T1/E1 Analyzer
Overview:
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.
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.
- Applying pure delay to a signal: A received signal is delayed before being retransmitted. This configuration is
illustrated in the figure below.
Interface
This section describes the operation of the controls in Delay/Attenuate - Single Timeslot Application.
- 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.
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.
- Processing the received signal data
The following are the steps to process a received signal:
- 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 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.
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.
Buyer's Guide:
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 DPT, DPE, PCT, PCE, HDT, HDE, DLT, DLE or UTE depending upon
the hardware.
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