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R2 MF Receiver TMS320C5000 DSP Code

Description: detects dual-tone signals to ITU Q.441 R2 signalling format. R2 transmission is done by choosing tone-pair combinations from the following two 6-tone groups:

The composite tone signal can send one of 15 digits (6C2 = 15) in each direction according to the digit code set.
        In the assembler interface, the software is in the form of 4 callable subroutines: two are for loading default parameters and initialising per-channel memory, one is for accessing any newly detected digit, and the main one is for per-sample processing. It can easily be used in a multi-channel mode: a pointer is set to each per-channel block of memory at each sub-routine call. By making multiple sub-routine calls, the code can be operated on blocks of samples. A C-callable wrapper can also be provided, wherein individual channels can be called from C to process multiple sample blocks.
         The code is near load-balanced so there is no significant MIPS variation per sample. To suit application, some digit detection parameters are made user-programmable. Operation can be at 8.0kHz or 9.6kHz sample rates. A user's guide is supplied.

Specification: the conditions under which R2 digit states are registered either a new digit when in the "pause" state or else a pause(non-digit) when in the "digit" state are as follows. The symbols Pth, Rtw signify that the parameter is user-programmable. All levels are per R2 tone.

The receiver is designed to pass the ITU Q.455 requirements.

Processor Load:

- #figures are for TMS320C54x operation with the assembler interface at 8.0kHz sampling

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