Digital dual tone multifrequency receiver
Date
1994
Authors
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Advisor
Atalar, Abdullah
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Publisher
Bilkent University
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Language
English
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Abstract
In this thesis, a suitable algorithm for detection of Dual Tone Multifrequency tones is proposed and implemented as a VLSI chip. The algorithm is based on an approximation of correlation. The input signal is correlated with the hardlimited versions of three sinusoids having 7Ty^3 phase difference. Also, a level detector is added to the algorithm. The algorithm only requires addition and subtraction, but no multiplication; and this reduces the complexity of the circuit. The implementation of the algorithm proposed has been realized as a fully integrated digital DTMF receiver chip using semi-custom layout techniques. The final chip is fabricated in 1-^m CMOS technology, and it has a total area of 24.78 mm^.