N-path first-order digital impulse correlator
D. E. Kerr, M. W. Lengyel · The Journal of the Acoustical Society of America · 1977
An N-path digital-filter approximation to the impulse correlator is developed. The high processing gain provided by impulse correlation makes it possible to clearly extract complex periodic signals from noise. The analogy between the impulse correlator and the N-path digital filter is examined. It is shown that the N-path filter approximates the impulse correlation with sufficient accuracy to be used for recovery of complex periodic signals from noise.