DTMF Signal high pass filter
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I am doing a DTMF problem. And I am having problems creating a HighPass filter to recognize freq with 1209. Here is my HighPass Filter that I have done.
% Designing HighPass Filter
[num den] = butter(N,.125,'High');
[HighP f] = freqz(num,den,8000,Fs);
High = abs(fft(keys)'.*HighP); %keys is the input matrix to dial phone number
Any suggestions on how to Fix my HighPass Filter?