sigmult.m

DSP课程的Matlab程序

function [y,n] = sigmult(x1,n1,x2,n2)

% implements y(n) = x1(n)*x2(n)

% -----------------------------

% [y,n] = sigmult(x1,n1,x2,n2)

%   y = product sequence over n, which includes n1 and n2

%  x1 = first sequence over n1

%  x2 = second sequence over n2 (n2 can be different from n1)

%

n = min(min(n1),min(n2)):max(max(n1),max(n2)); % duration of y(n)

y1 = zeros(1,length(n)); y2 = y1;              % 

y1(find((n>=min(n1))&(n<=max(n1))==1))=x1;     % x1 with duration of y

y2(find((n>=min(n2))&(n<=max(n2))==1))=x2;     % x2 with duration of y

y = y1 .* y2;                                  % sequence multiplication