Co-channel interference filter for television receiver

Claim 3

The method of claim 1 wherein said receiving step comprises receiving a digitally encoded television signal including a predetermined reference signal and wherein said determining step comprises analyzing said received reference signal for determining the relative strength of said undesired co-channel interference.

Claim 4

The method of claim 2 wherein said comb filtering step comprises establishing a comb filter response having a plurality of spaced nulls for attenuating said undesired co-channel interference, the depth of said nulls being a function of said determined relative strength.

Claim 5

The method of claim 3 including establishing the depth of said comb filter response nulls as a direct function of said determined relative strength.

Claim 6

For use in a television signal receiver, a co-channel interference filter comprising: means for receiving a digitally encoded television signal transmitted over a selected television channel, said received signal including a predetermined reference signal and being characterized by undesired co-channel interference; means responsive to said reference signal for developing a control signal representing the relative strength of said undesired co-channel interference; first filter means coupled to said means for receiving and being responsive to said control signal for reducing said undesired co-channel interference and for providing an output signal including an intersymbol interference component in response to said digitally encoded signal; and an intersymbol interference filter coupled to said first filter means and being responsive to said control signal for reducing said intersymbol interference component of said output signal for reconstructing said digitally encoded signal.

Claim 7

For use in a television signal receiver, a co-channel interference filter comprising: means for receiving a digitally encoded television signal transmitted over a selected television channel, said received signal including a predetermined reference signal and being characterized by undesired co-channel interference; means responsive to said reference signal for developing a control signal representing the relative strength of said undesired co-channel interference; first filter means coupled to said means for receiving and being responsive to said control signal for reducing said undesired co-channel interference and for providing an output signal including an intersymbol interference component in response to said digitally encoded signal; and an intersymbol interference filter coupled to said first filter means and being responsive to said control signal for reducing said intersymbol interference component of said output signal for reconstructing said digitally encoded signal.

Claim 8

The co-channel interference filter of claim 5 wherein said first filter means comprises a comb filter having a plurality of spaced nulls for attenuating said undesired co-channel interference, the depth of said nulls being established in response to said control signal.

Claim 9

The co-channel interference filter of claim 6 wherein the depth of said comb filter nulls are established in direct relation to the strength of said undesired co-channel interference as represented by said control signal.

Claim 10

The co-channel interference filter of claim 7 wherein said comb filter comprises a feed-forward path including a variable gain amplifier responsive to said control signal.

Claim 11

The co-channel interference filter of claim 8 wherein said intersymbol interference filter comprises a feedback path including a second variable gain amplifier responsive to said control signal.

Claim 12

The co-channel interference filter of claim 9 wherein the gain of said first amplifier is variable in response to said control signal between a level of about one for establishing the depth of said nulls at a maximum value and a level of about zero for establishing the depth of said nulls at a minimum value.

Claim 13

The co-channel interference filter of claim 5 wherein said reference signal comprises a pseudo random code for use in controlling a channel equalizer.

Claim 14

The co-channel interference filter of claim 5 wherein said reference signal comprises a chirp signal.

Claim 15

The co-channel interference filter of claim 5 wherein said means for receiving is coupled to a cable television network and wherein said undesired co-channel interference is produced as the result of composite triple beats developed in said network.