MF Receiver TMS320C5000 DSP Code
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
900/ 780/ 660/ 540Hz
composite tone signal can send one of 15 digits (6C2 = 15) in each direction
according to the digit code set.
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.
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.
>= Pth (Pth >= -45dBm)
< Pth & >= -3dBm
tone +6dBm is peak
<= Rtw (Rtw<= 10dB)
receiver is designed to pass the ITU Q.455 requirements.
#figures are for TMS320C54x operation with the assembler interface at
NOW, sale is under licence - integration support offered