Author : Vidyashree A.C 1
Date of Publication :7th May 2016
Abstract: Dual-tone multi-frequency (DTMF) is an international signaling standard for telephone digits(number buttons). These signals are used in touch-tone telephones as well as many other areas. Since analog devices are rapidly changing with digital devices, digital DTMF decoders become more important. The subject of this paper is to build a dual-tone multi-frequency(DTMF) signal detector. There are many algorithms for DTMF detection, and among all of them the chosen one is Goertzel’s algorithm. It is one of the simplest algorithms of all and it is very often used in practical realizations. We have used the Altera DE2-115 board comprising of AUDIO CODEC,FPGA chip, RAM,SD Card etc. First the DTMF(Dual Tone Multi Frequency)signal is passed through AUDIO CODEC where the analog signal is converted to digital signal. Then the samples obtained are passed through a bank of goertzel filters loaded on FPGA,where the frequency is detected. simulations are carried out using quartus II tool and RTL code of verilog.
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