Autocorrelation is a classic technique for finding signals in the presence of noise. Prior art autocorrelation techniques involve delaying the signal by predetermined increments, multiplying the delayed signal by the incoming signal, averaging the result, and repeating the above steps for predetermined time delays. The prior art requires thousands of multiplications for every time period.
For certain applications, for example, applications relating to lasers, time periods are short, on the order of 50-100 nanoseconds. In such applications, the number of multiplications required for each time period exceeds the capabilities of prior art systems. The motivation of the invention is to provide a simpler, more cost effective autocorrelation method and apparatus which works as well as the prior art.