ovrlpsav.m

％realize overlapped-save method ％y:output sequence ％x:input seqence ％h:filter impulse response s

function [y]=ovrlpsav(x,h,N)
%realize overlapped-save method
%y:output sequence 
%x:input seqence
%h:filter impulse response sequence 
%N:length of each segment
%重叠保留法实现分段卷积
Lenx=length(x);M=length(h);
M1=M-1;L=N-M1;
h=[h,zeros(1,N-M)];              %将序列h(n)补零到长度为N
%x(n)的前面补上M1-1个零，以修正第一段中的前面M-1个样本，
%在x(n)的后面补零，使得下面循环语句的索引不会超过范围
x=[zeros(1,M1),x,zeros(1,N-1)];
K=floor((Lenx+M1-1)/(L));          %确定分成多少段
Y=zeros(K+1,N);
for k=0:K
    xk=x(k*L+1:k*L+N);           %取出每一段对应的输入序列
    Y(k+1,:)=circonv2(xk,h,N);    %对每一段分别进行处理
end
Y=Y(:,M:N)';
y=(Y(:))';                       %重叠保留
y=y(1:Lenx+M-1);                 %取出实际的输出序列
if ~any(imag(h))&~any(imag(x))
    y=real(y);                   %判断是否为实数序列
end