Home
Modems
Telephony
Audio
Utilities
Consultancy
Glossary
Index
Contact us

DTMF Transmitter TMS320C5000 DSP Code

Description: generates digit signals to standard Dual Tone Multi-Frequency (DTMF) telephone format. With DTMF, the 16 possible digits are each signified by pairs of tones, one from a "low" group - 697Hz, 770Hz, 852Hz, 941Hz - and the other from a "high" group - 1209Hz, 1336Hz, 1477Hz, 1633Hz.
         The user is responsible for supplying the codes of digits to be dialled and for accepting each transmit sample. Digits can be stored in a queue. The software is in the form of four callable subroutines: one sets common-channel default parameters, one initialises per-channel memory, one is for loading each new digit into each digit queue, and one is for per-sample generation.
         To suit applications, the following parameters are made user-programmable: low- and high-tone transmit powers, digit-on timing, digit-off timing, digit queue length. For test purposes, continuous transmission can be set. Sample rates of 8.0kHz or 9.6kHz can be operated.
         In the assembler interface, the software can be operated 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 also generate blocks of samples. A C-callable wrapper can also be provided, wherein individual channels can be called from C to generate multiple sample blocks. A user's guide is supplied.

Specification: the values PL, PH and Ton, Toff are user-programmable.

Processor Load:

- #figures are for TMS320C54x operation with the assembler interface at 8.0kHz sampling
- *for 16-digit queue

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