receiv1.m

双音多频编解码系统

function num =Receiv1(hn)
phone='123A456B789C*0#D';
fs=8000;
fl=[697 770 852 941];
fh=[1209 1336 1447 1633];
hnr=hn(1,361:440);
% figure,stem(hnr);
fn=fft(hn);
N=800;
w0=[1:N];
w=[0:N/2-1]/N*fs;
ffn=abs(fn(1,1:N/2));
% figure;
% subplot(3,1,1),plot(ffn);
% title('ffn');
window=[rectwin(100);zeros(N/2-100,1)];
ll=ffn.*window';
ffl=w(ffn==max(ll));
hh=ffn-ll;
ffh=w(ffn==max(hh));
% subplot(3,1,2),plot(ll);
% title('ll');
% subplot(3,1,3),plot(hh);
% title('hh');
for i=1:4
    if abs(ffl-fl(i))<=fl(i)*0.03
        a=i;
    end
end
for j=1:4
    if abs(ffh-fh(j))<=fh(j)*0.03
        b=j;
    end
end
num=phone((a-1)*4+b);