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V.22bis Data Pump Software for Texas TMS320C54x/C55x & C2xx/C5x DSPs

This software implements the ITU Data Modem functions V.22bis and V.22, which provide full-duplex data transmission at rates of 2.4, 1.2, & 0.6kb/s over the telephone network. Duplex channel separation is achieved by band splitting. Good error performance is assured by the use of adaptive equalisation. The software is in the form of two callable subroutines, one for initialisation and one for processing of input/output data and sample blocks. The user is responsible for interfacing sample and data input & output to hardware. By making multiple sub-routine calls, the code can operate on blocks of samples. Data memory is offset-addressed in the ‘C54xC55x version, so the code re-entrant for implementing multiple modems on a single DSP. A comprehensive user's guide is provided with the code. Test results are available.

Interfaces: at the sample interface, the code can operate at 9.6kHz or 8.0kHz sample rates. Transmit and receive samples are transferred on a common clock, to which the transmit clock is synchronised. The receive clock is interpolated in the DSP code for synchronisation to the far-end modem. At the data interface, data is transferred in buffers under pointer control. At the control interface, one 16-bit control word sequences operations and sets parameters, and two diagnostic words convey data transfer and receiver status.

Performance: near matched-filter performance is obtained over both flat and very severe channels.

• SNR for 10^-6 error rate at 2.4kb/s: 13.5dB - Flat Channel ; 14.0dB - Bell 3002 Channel

DSP Load - 'C54x/'C55x version: parameters given for operation at a 9.6kHz sample rate - operation at an 8.0kHz sample rate requires an extra 0.3MIPS, 20 data memory and 0.2k program memory words:

• MIPS: 3.5

• Data memory: 228 words

• Program memory: 2.5k words

DSP Load - 'C2xx/'C5x version: parameters given for operation at a 9.6kHz sample rate - operation at an 8.0kHz sample rate requires an extra 0.6MIPS, 30 data memory and 0.3k program memory words:

• MIPS: 3.4

• Data memory: 218 words

• Program memory: 2.4k words

Availability: NOW - sale is under licence - integration support offered