# Homework Help: Cross correlation

1. Sep 1, 2007

### EvLer

1. The problem statement, all variables and given/known data
A signal x(t) is transmitted and received back as y(t) and sampled in the receiver, so we get a DT signal
y[n] = ax[n-D] + w[n], where w[n] is noise

baiscally i need to explain how we can measure the time delay by computing crosscorrelation Ryx(l).

My undestanding is:
cross-correlation measures how similar the signals are, so if we ccompute cross correlation of a signal with its reflected version, we will get shifted peaks, and the amount of shifting is the delay

Is this correct?

2. Sep 10, 2008

### sravanign

3. Jan 22, 2012

### Evo8

I realize this is a super old thread. But I was about to ask the exact same question. So I figure I would try bumping it up.

My understanding is very similar to EvLer's. I have a transmitted pulse x(t) and the received pulse is x(t). These are received by a receive and processed to determine the time delay. The distance from the reflecting object is the time delay.

Can anyone provide a little more information to make things clearer or confirm what is above in post or Evler's?