Enhanced pulse time-of-arrival detector

Claim 1

A detector for detecting a communication pulse, having a main pulse portion and at the edges thereof at least a single edge pulse portion which in substantially opposite in phase with respect to said main pulse portion, in the presence of noise comprising: receiving means for receiving said communication pulse; quadrature reference signal source means for producing first and second quadrature reference signals; multiplier means connected to said receiving means and to said quadrature reference signal source means for multiplying said received communication pulse and said first and second quadrature reference signals, said multiplier means providing a multiplier output signal; clock means for supplying clock pulses; correlation signal means connected to said multiplier means and including accumulator means, said accumulator means, responsive to said clock pulses to shift through said multiplier output signal and having fewer storage locations than would be required to store all of a signal as long as said communication pulse, said correlation signal means providing a correlation signal having sloped leading and trailing edges, said correlation means being effective for producing a steeper slope in said leading and trailing edges corresponding to each said edge pulse portion; and, comparator means connected to said correlation signal means for providing a pulse detection output signal when said correlation signal crosses a predetermined threshold, said threshold being set at a level to detect the leading and trailing edges of said correlation signal, said comparator means comprising means for detecting the intersection of both leading and trailing edges of said correlation signal with said predetermined threshold.