"We’ve developed this class of detector because telecom equipment manufacturers demand carrier class performance." 
Adaptive Digital's tone detector has been deployed since 1995, hosted on numerous Digital Signal Processors.

DTMF Detect Software for ARM Devices

Adaptive Digital's proprietary DTMF algorithm maintains a strict compliance with industry specifications Bellcore/Telcordia GR506 and ITU Q455.

FEATURE

  1. Designed for multi-channel operation
  2. Functions are “C” callable
  3. Low false alarm rate
  4. Accepts linear PCM

Sampling Rate: 8 kHz
Frame Size: Programmable
SNR: 24 dB
Minimum Duration: 29 msec.
False Alarm Rate: 8 (30 minute Mitel Test Tape)


AVAILABILITY

ADT DTMF Detect is available on the following Platforms: Other configurations are available upon request.

Product Number device Platform
adt_dtmf_det _armM3/Stellaris ARM Cortex-M3
adt_dtmf_det _armM4 ARM Cortex-M4
adt_dtmf_det _armA8 ARM Cortex-A8
adt_dtmf_det _armA9 ARM Cortex-A9
adt_dtmf_det _armA15 ARM Cortex-A15

DESCRIPTION

The complex DTMF tone detect algorithm determines the single generated digit by extracting the two frequencies from the input signal, allowing for tolerances such as frequency offset and distortion such as additive noise, and then checking them to see if together they qualify as one of the digits. A DTMF detector rejects any tone frequency that is not the sum of one high and one low tone. This prevents speech and noise signals from being interpreted as DTMF tones.

Adaptive Digital's tone detector has been deployed since 1995, and hosted on numerous platforms.

DTMF refers to the signal generated when you press a digit on a telephone's touch keypad. The term DTMF stems from the fact that whenever a telephone push button is pressed, the phone generates two specific tone frequencies that are the algebraic summation of the amplitude of the two frequencies. Four frequencies are used for the rows and four for the columns, for a total of 8 frequencies and 16 possible combinations.

The complex DTMF tone detect algorithm determines the single generated digit by extracting the two frequencies from the input signal, allowing for tolerances such as frequency offset and distortion such as additive noise, and then checking them to see if together they qualify as one of the digits. A DTMF detector rejects any tone frequency that is not the sum of one high and one low tone. This prevents speech and noise signals from being interpreted as DTMF tones.

SPECIFICATIONS

ARM® DEVICES

DTMF ARM Cortex-A8/A9/A15

CPU UTILIZATION & MEMORY REQUIREMENTS
All Memory usage is given in units of byte.

Function MIPs Per-Channel Program Memory Data Memory Per-Channel Data Memory Scratch Memeory
DTMF Detect 3.0 3104 3792 152 400
CPRG Detect 1.6 1152 2992 152 400
Tone Detect Common -- 3376 -- -- --

 

DTMF ARM Cortex-M3/M4

CPU UTILIZATION & MEMORY REQUIREMENTS
All Memory usage is given in units of byte.

Function MIPs Per-Channel Program Memory Data Memory Per-Channel Data Memory
DTMF Detect 4 1958 3442 148

We specify MIPS (Millions of Instructions Per Second) as MCPS (Millions of Instruction Cycles Per Second). Unless otherwise specified, peak MIPS are indicated.

FUNCTION

API function call summary

InitDTMFDetect(. . .)               Initializes DTMF Detector

DTMF_Detect(. . .)                  Executes DTMF Detector

 


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A DTMF detector rejects any tone frequency that is not the sum of one high and one low tone.
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