WINDOWS CLIENT/SERVER

T1/E1 Analysis

Static DSP Operations

Overview

Scripted DSP commands provide the ability to specify a sequence of digital signal processing steps to be performed on incoming and/or outgoing timeslots. The WCS DSP Operation module allows real-time as well as offline testing using DSP commands to perform functions such as Amplification/Attenuation, Delay, Filter, File Tx/Rx, Logical operations, Echo Cancel, and so on.

Complex echo paths and complex block diagram operations can be easily simulated using the following functions: sum, invert, filter, delay, amplify, attenuate, bxor, bor, brev, bnot, band, infile, outfile, white noise, tone, dual tone, phase shift, dtmf digits, mf digits, mfcr2 digits, power monitor, signaling bits monitor, const, bytes, and many other operators.

Example processing structures that can be accomplished are shown below:

In Figure 1, digitally synthesized sources (generators) of tone, noise, DTMF digits, MF digits, and dualtone are summed and transmitted into timeslot 5.

DSP Static Operations

In Figure 2, multiple dualtone generators with possibly different parameters are summed and transmitted into timeslot 23.

DSP Static Operations

In Figure 3, receive timeslots 1, 2, and 3 are summed and transmitted into timeslot 7.

DSP Static Operations


In Figure 4, receive timeslot 5 is summed with delayed and attenuated versions of itself and transmitted back into timeslot 5. Such a structure may be useful in modeling echo paths and testing echo cancellers.

DSP Static Operations

In Figure 5, a more complex structure for echo path modeling is shown. Three parallel echo paths are summed with a digitally synthesized tone and noise and a PCM file.

DSP Static Operations

In Figure 6, receive timeslot 5 is inverted, summed with itself, and transmitted into timeslot 5. This is an example of a perfect canceller.

DSP Static Operations


DSP Static Operations using C++ client

Transmit filtered tones and white noise

Transmit filtered tones and white noise

This script transmits two tones at different frequencies along with white noise and DTMF digits. The output is obtained through a filter.

Download scripts for Transmit filtered tones and white noise



Adding speech and noise to the receive data

Adding speech and noise to the receive data

This script transmits the amplified speech file with white noise and the data received on a particular timeslot.

Download scripts for Adding speech and noise to the receive data.



Adding noise and phase shift tone to the speech data

Adding noise and phase shift tone to the speech data

This script transmits an amplified speech file with a continuously phase shifted tone combined with a white noise through a filter.

Download scripts for Adding noise and phase shift tone to the speech data.



Testing Arithmetical Functions on Incoming Bit Stream

Testing Arithmetical Functions on Incoming Bit Stream

This script performs various types of arithmetical functions on the incoming bit stream.

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Double talk simulation for echo canceller testing

Double talk simulation for echo canceller testing

This script emulates the far end and near end call for echo canceller testing.

Download scripts for Double talk simulation for echo canceller testing.



Tone Decoder and ADSI decoder

Tone Decoder and ADSI decoder

The DSP commands also allow to monitor Tones, Digits, and other traffic generated using above static DSP operations. Additionaly, with the new Tone Decoder and ADSI decoder DSP commands, it is possible to detect Caller IDs including CID, CIDCW (Call Waiting), VMWI (Visual Message Waiting Indicator) signal types. Supported encoding formats include alaw, mulaw, pcm16, pcm14, and pcm13.

In the above screenshot the sample .ula file has a pre-recorded caller id information, here decode tones command is used to decode the caller id information and notify as an event. Similarly, decode tones, tone decoder, or adsi decoder commands can also be used to decode CID, CIDCW, and VMWI information.

Download the sample scripts to detect caller id.



Other Sample Scripts

List of some sample DSP scripts using TCL client