预处理.m

线性预测这一术语是维纳于1947年首次提出的

 [C,L]=wavedec(x,3,'db4');
   [thr,sorh,keepapp]=ddencmp('den','wv',x);
   de_noise=wdencmp('gbl',C,L,'db4',3,thr,sorh,keepapp);
   xx=de_noise;
   x1=filter([1 -0.9375],1,xx);
   x=x1/max(abs(x1));
   y=enframe(x,256,80);
   amp=sum(y.*y,2);
   temp1=enframe(x(1:length(x)-1),256,80);
   temp2=enframe(x(2:length(x)),256,80);
   signs=(temp1.*temp2)<0;
   diffs=abs(temp1-temp2)>0.02;
   zcr=sum(signs.*diffs,2);
   ef=amp.*zcr;
   amp=amp';
   ef=ef';
   zcr=zcr';
   s1=qishiduandian(ef);
   s2=jieshuduandian(ef);
   x2=x((s1-1)*80+1:(s2-1)*80+256);