Modified digital correlator and its estimation errors

The method of using auxiliary random noise to unbias the output of the multilevel digital correlator is investigated. It is shown that any random noise satisfying certain conditions may be used. The uniformly distributed noise that has been used previously in the polarity-coincidence correlator is a special case. Discretely distributed auxiliary noise, although not satisfying the conditions, has the same effect as quantizing the input signals more finely. The mean-square error of this modified digital correlator is analyzed.