I believe that something similar is used for digital music in the error correction area. If the decoder can't tell if it is receiving a 1 or 0 due to damage to the signal or not being able to be read properly off a disc the decoder will do some kind of math to guess which it is. This isn't repeating anything per say and the 120hz sees the starting point and ending point but fills in a center point. I think this may be what you were asking though.