Dual Tone Multi Frequency Encoder and Decoder

Function files to implement DTMF encoder and decoder(uses Goertzel's Algorithm)

dtmf_encode: Takes the sequence to be encoded as the input argument. Returns the signal vector.

dtmf_decode: Takes the signal vector as the input argument. Returns the decoded sequence.

gfft: Used by dtmf_decode to compute the DFT of input samples

dtmf_doc: Documentation of the files with theory and algorithm.

Reference : Digital Signal Processing: A Computer Based Approach by Sanjit K. Mitra, McGraw-Hill Inc., ISBN:978-0-07-042953-6