ovrlpsav.txt

数字信号处理中实现线性卷积的M文件

function [y]=ovrlpsav(x,h,N)
lenx=length(x);M=length(h);
M1=M-1;
l=N-M1;h=[h,zeros(1,N-M)];
x=[zeros(1,M1),x,zeros(1,N-1)];
K=floor((lenx+M1-1)/(l));
Y=zeros(K+1,N);
for k=0:K
    xk=x(k*l+1:k*l+N);
    Y(k+1,:)=circonvt(xk,h,N);
end
Y=Y(:,M:N)';
y=(Y(:))';

function y=circonvt(x1,x2,N)
if length(x1)>N
    error('必须>=x1的长度')
end
if length(x2)>N
    error('必须>=x2的长度')
end
x1=[x1,zeros(1,N-length(x1))];
x2=[x2,zeros(1,N-length(x2))];
m=[0:1:N-1];
x2=x2(mod(-m,N)+1);
H=zeros(N,N);
for n=0:1:N-1
    H(n+1,:)=cirshftt(x2,n,N);
end
y=x1*H';

function y=cirshftt(x,m,N)
if length(x)>N
    error('N必须>=x的长度')
end
x=[x zeros(1,N-length(x))];
n=[0:1:N-1];
n=mod(n-m,N);
y=x(n+1);