Matlab program dtmf generation

Full documentation about the matlab code is available on the following link:. By mdipaolo Follow. More by the author:. About: Ph. D in physics and telecommunication engineer.

The most important issues are: 1- to generate a file with the signal in the digital format. There are 12 distinct tones. When any key is pressed the tone of the column and the tone of the row are generated. As an example, pressing the '5' button generates the tones Hz and Hz. The frequencies were chosen to avoid harmonics: no frequency is a multiple of another, the difference between any two frequencies does not equal any of the frequencies, and the sum of any two frequencies does not equal any of the frequencies.

At the receiver the tone frequencies are detected and the number decoded. The DFT algorithm can be used to detect frequencies, but since there are only 7 frequency components 4 low frequencies and 3 high frequencies , a more efficient method is the Goertzel algorithm. This method detects the frequency components by passing the received signal through 7 bandpass filters. The filter bandwidths are adjustable as a percentage of the center frequency by adjusting the bandwidth parameter on the DTMF Receiver block mask.

When you run the simulation, the spectrogram of the received tone will be constructed. If you use the version of the model designed for audio hardware, the received tone is played through the system soundcard.

Those values in the matrix table seem to me magic as well, however I have the restriction to use them. Add a comment. Daniel Daniel Sign up or log in Sign up using Google.

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