Archive.zip_DTMF fft Goertzel_Goertzel_dtmf_dtmf用fft解调

clear;clc; [y,fs] = wavread('PhoneNumberA.wav'); n = length(y); % remove low frequency noise Wn=650/4000; [b,a]=butter(3,Wn,'high'); y=filter(b,a,y); %threshold equals half of the average energy threshold=0.5*sum(y.^2)./n; N=512; framenum=floor(n/N); fq=[697,770,852,943,1209,1336,1477,1663]; fqnum=length(fq); %find useful segments r=[];num=blanks(7); e=zeros(1,framenum); startframe=zeros(1,7); count= ones(1,7); flag=0;n=1; for i=1:1:framenum frame=y(N*(i-1)+1:N*i); e(i)=sum(frame.^2)/N; %count the number of useful continuous frames switch flag case 0 if(e(i)>=threshold) startframe(n)=i; flag=1; else flag=0; end case 1 if(e(i)>=threshold) count(n)=count(n)+1; flag=1; else flag=0; n=n+1; end end end figure plot(e); line(1:1:framenum,threshold,'Color','r','LineStyle','-' ); %discriminate the digits figure for i=2 r=y(N*(startframe(i)-1)+1:N*(count(i)+startframe(i)-1)); R=fft(r); subplot(7,1,i); plot(abs(R)); axis tight fq1=1100;%divide the segment into fq_low & fq_high part n1=round(fq1/fs*count(i)*N); m1=[]; m1=R(1:n1); m2=[]; m2=R(n1+1:count(i)*N/2); %find peak in each part and the corrisponding fq [max_value1,index1] = max(m1); [max_value2,index2] = max(m2); index2=index2+n1; fqlow=index1/(count(i)*N)*fs; fqhigh=index2/(count(i)*N)*fs; %match the calculated fqs to the specific 8 basic fqs for j1=1:1:fqnum; if abs(fqlow-fq(j1))<20 fqlow=fq(j1); end end for j2=1:1:fqnum; if abs(fqhigh-fq(j2))<20 fqhigh=fq(j2); end end fq_mx=zeros(1,2); fq_mx=[fqlow,fqhigh]; if fq_mx==[fq(1),fq(5)] num(i)='1'; elseif fq_mx==[fq(1),fq(6)] num(i)='2'; elseif fq_mx==[fq(1),fq(7)] num(i)='3'; elseif fq_mx==[fq(2),fq(5)] num(i)='4'; elseif fq_mx==[fq(2),fq(6)] num(i)='5'; elseif fq_mx==[fq(2),fq(7)] num(i)='6'; elseif fq_mx==[fq(3),fq(5)] num(i)='7'; elseif fq_mx==[fq(3),fq(6)] num(i)='8'; elseif fq_mx==[fq(3),fq(7)] num(i)='9'; elseif fq_mx==[fq(4),fq(6)] num(i)='0'; end end disp(['The phone number is:',num]);