Ghost cancellation reference signal with bessel chirps and pn sequences, and tv receiver using such signal

Abstract

Composite ghost cancellation reference (GCR) signals that make available both a chirp and a PN sequence during the same VBLI in each successive field facilitates the more rapid and efficient calculations of ghost cancellation and of equalization, on a continuing basis. A television receiver for use with such composite GCR signals includes means for separating the chirp and PN sequence portions of the GCR signals from the remainder of the composite video signal, a ghost cancellation filter and an equalization filter connected in cascade to respond to the composite video signal and provided each with adjustable filtering weights, means responding to the separated chirp portions of the GCR signals to calculate a discrete Fourier transform (DFT) therefrom, means responding to that DFT to determine the adjustable filtering weights of the ghost cancellation filter, and means responding to the separated PN sequences to determine the adjustable filtering weights of the equalization filter.