findlowerfreq.m

DTMF编解码在MATLAB中的仿真（gui设计）

%FinLowerFreq.m
function number=FindLowerFreq(Signal)
Freq=[697,770,852,941];
temp=0;
for n=1:length(Freq)
    W0=Freq(n);
    B=DesignLowerFilter(W0);
    Out=filter(B,1,Signal);
    Fout=max(abs(fft(Out)));
    if(Fout>temp)
        number=n;
        temp=Fout;
    end
end