Debraj has been working on this project for DTMF decoding using the Goertzel algorithm on a PIC.
Goertzel algorithm is well known in the DSP domain. It is used to detect the presence of a frequency or a number of frequencies. This algorithm is popular as the calculation required for implementation is lesser as compared to other techniques such as DFT (FFT), when a smaller number of frequencies are to be detected.
My project uses PIC18F4520 and Goertzel algorithm to detect DTMF frequencies. The code is written entirely in “C”.
The complete explanation of the algorithm, circuit and code can be found on Debraj’s website.
Via the contact form.