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Abstract

A co-channel interference filter and a method for reducing co-channel interference for use in a television receiver. The television receiver receives a signal transmitted from a transmitter, the received signal having an encoded digital television signal component, a co-channel interference component, and a noise component, wherein the encoded digital television signal component is characterized as an N-level vestigial sideband (VSB) signal of Reed-Solomon (R-S) encoded, byte interleaved and trellis encoded symbols c.sub.k, i (for i=1 to 12), where N corresponds to a number of levels, and further wherein each symbol c.sub.k, i is derived from original symbol bits a.sub.k, i.sup.1 and a.sub.k, i.sup.2 (for i=1 to 12), respectively. The co-channel interference filter comprises a generator for generating a characteristic coefficient .alpha. in response to a received television signal, .alpha. being dependent upon an amount of the co-channel interference and noise components present in the received signal. A variable comb filter is filters the received signal and provides a filtered output signal, the variable comb filter having a characteristic response of 1-.alpha.D*, wherein D* represents a delay of twelve VSB symbol intervals. An equalizer and phase tracker equalizes and phase tracks the filtered output signal, the equalizer and phase tracker outputting an effective output signal represented by an expression d.sub.k, i =c.sub.k -60C.sub.k-1, i (for i=1 to 12), where d.sub.k, i and c.sub.k-1, i further correspond to an instantaneous symbol and a delayed symbol, respectively. A trellis decoder, responsive to .alpha., trellis decodes the output signal d.sub.k, i and provides a trellis decoded output signal of symbol bits a.sub.k, i.sup.1 and a.sub.k, i.sup.2 of trellis decoded symbols, corresponding to original symbol bits a.sub.k, i.sup.1 and a.sub.k,i.sup.2, respectively, and further removes the ISI component introduced by the variable comb filter.

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First Claim