Spectral analysis of a cross correlation function
cross-correlation would determine the time-delay. but the scale of signals' length and the delay value should be considered precisely. I mean if you have two long signal of, for say, 100sec and you are looking for a time delay in an order of 1msec, you don't need to do cross-correlation over the whole 100sec. Instead, choose a proper window time (in msec order) of two signal and then perform the cross-correlation.