Dual Tone Multiple Frequency (DTMF) detection on microcontrollers

Mr. Amey Deosthali
Schlumberger Technology Corporation
Sugarland, TX

Friday, February 26th, 2:00 PM, ENS 302

deosthali@sugar-land.spc.slb.com

Abstract

Dual Tone Multiple Frequency (DTMF) signaling is used in telephone dialing, digital answering machines, and interactive banking systems. DTMF signals can be generated by adding a low frequency sinusoid (below 1000 Hz) and a high frequency sinusoid (above 1000 Hz). Decoding DTMF signals amounts to detecting two sinusoids in noise. International Telecommunications Union (ITU) provides specifications for decoding DTMF signals. An ITU-compliant DTMF detector needs to meet all the ITU requirements. Although a lot of DTMF decoders currently exist in the market, only one of them is ITU-compliant. Most decoders report compliance with Bellcore standards which are a weaker subset of the ITU standards. Additionally, these detectors require 16-bit data. In this talk, we present the first DTMF decoder which meets all the ITU specifications when implemented using 8-bit arithmetic. The decoder can be implemented on a low-cost microcontroller like the PIC series microcontrollers from Microchip Technology Corporation. We will present the new algorithm and discuss the implementation issues related to its microcontroller implementation.

Biography

Amey A. Deosthali obtained his bachelor's degree in Electronics and Telecommunications from University of Pune, India. He received a MSEE degree from UT Austin in 1998. He is currently employed with Schlumberger Technology Corporation in Sugar Land, Texas. His main interest is embedded signal processing.

A list of Signal and Image Processing Seminars is available at from the ECE department Web pages under "Seminars". The Web address for the Signal and Image Processing Seminars is http://anchovy.ece.utexas.edu/seminars