Decode the keys in DTMF using FFT

UPDATE:

The problem was solved! See the first comment.

I need to detect the keys pressed in the wav file using the FFT. But I'm completely stuck with it, just don't know what to do. I have read that you can detect the tones with the help of Goertzel algorythm, but, again, I haven't found nor explanation for it nor any example of working code. With audioread I got the wave and created the plot of it, but what should I do next to identify the frequencies for each key and filnally the keys?

Can someone please share with me an algorithm how to solve this problem?

[Pavel Musorsky]

Finally I have made it! I don't clearly understand it whole cause I used the documentation about Goertzel but it works!

IT JUST WORKS!

Remembering all the pain I got during creation of it I will leave it there. In hope that it will save someone in future.

[Abigail Nwk]

Thank you so much!! can i have the audiofile that you used ? the qwer.wav

[Pavel Musorsky]

Just use this site to create any sequence of keys and download the wav file.

https://www.audiocheck.net/audiocheck_dtmf.php

Then rename it appropriately and put it in the folder where your matlab code lies. I promise you the code will give you the same sequence.

[Abigail Nwk]

It finally worked!

I used other dtmf generators and couldn't get the same sequence. Now i tried with the generator you gave and it worked

Thank you

[Pavel Musorsky]

My code is not an absolute solution and I still don't know how exactly it works. But did your generator have 9 keys or 16 like mine?

[Abigail Nwk]

The generators i used had 16 keys too. I need this for a project, and now that the code works i have to explain every instruction used

[Muhammad Shafiq]

Hi guys the code FFT.m is not running properly ,I have set the path of audio file properly. Need guidance in running FFT.m. Thanks

[Pavel Musorsky]

Did you use the wav file? And does it lie in the same folder as your project?

[Abdul Rahim Mohammad]

Hi Pavel,

I used the code with a wav file generated from your suggested link but the following error pops up:

Output argument "c" (and maybe others) not assigned during call to "FFT>detect".
Error in FFT (line 27)
    KEYS = [KEYS,detect(val)]; 

Could you also specify how to use the mat file as well, as in how to use the generated wave file and your file?

I reckon this might be a incomplete code snippted since the function you made takes no input arguments, I am sorta new to MATLAB and this seems extemely out of place compared to python. Thanks!

Answer 1

[Leonardo Aquino]

hi @Pavel Musorsky, i have a problem with the ejecution your code, i have this error:

Error using reshape
Size arguments must be real integers.

Error in fft (line 11)
dataS = reshape(data(1:height*width),width,height)