Contents
Demo of correlation function: x1 is a sinc function.
Because sinc function is symmetric, correlation and convolution give the same result.
clear all, close all t = linspace(-2,2,1000); x1 = sinc(t); y1 = conv(x1,x1); figure(1) subplot(2,1,1) plot(x1) subplot(2,1,2) plot(y1)

x2 is a random signal.
We use conv(x2, flipup(x2)) to actually calculate the correlation.
x2 = randn(length(t),1); y2 = conv(x2, flipud(x2)); figure(2) subplot(2,1,1) plot(x2) subplot(2,1,2) plot(y2)
