Amplitude limiting applied to a sensitive correlation detector

It is shown that the stability of a sensitive correlation detector can be improved by limiting the amplitudes of the voltages in either one or both input channels. The loss of output signal/noise ratio compared to an ideal multiplier-correlator is determined as a function of limiting level for both cases. The output signal/noise ratio of an unstable multiplier/correlator can be considerably less than the theoretical maximum. Thus, depending upon the source of the instability, it is possible to increase the output signal/noise ratio until an optimum value is reached by the technique of amplitude limiting. Further advantages of this technique are discussed in the paper.