Digital television signal processing system including a co-channel rejection filter

Claim 2

In a television receiver for receiving a television signal representative of digital video information, apparatus comprising: an input signal translation network; a first equalizer responsive to signals from said signal translation network; a baseband demodulator responsive to an output signal from said equalizer; and a notch filter included in said baseband demodulator for filtering baseband and near-baseband video signals, said filter exhibiting a response including significant amplitude attenuation at a prescribed frequency for attenuating interferer signal components subject to contaminating said received signal.

Claim 3

Apparatus according to claim 1 and further comprising a second equalizer responsive to signals produced by said demodulator after filtering by said notch filter.

Claim 4

Apparatus according to claim 1, wherein said notch filter is a FIR digital filter for attenuating co-channel interferer signals at picture carrier and chrominance carrier frequencies; and said signal translation network is a frequency converter.

Claim 5

Apparatus according to claim 3, wherein said notch filter exhibits an upper bandedge excess frequency region encompassing a co-channel sound carrier frequency.

Claim 6

In a system for receiving a signal representative of digital video information, apparatus comprising: an input processor; an input equalizer responsive to signals from said input processor; a carrier recovery network responsive to an output signal from said equalizer for providing a demodulated baseband video signal; an output signal processor for processing said baseband video signal; and a filter included in said carrier recovery network for filtering baseband and near-baseband video signals, said filter exhibiting a response including significant amplitude attenuation at a prescribed frequency for attenuating .narrowband interferer signal components subject to contaminating said received signal.

Claim 7

In a system for receiving a signal representative of digital video information, apparatus comprising: an input processor; an input equalizer responsive to signals from said input processor; a carrier recovery network responsive to an output signal from said equalizer for providing a demodulated baseband video signal; an output signal processor for processing said baseband video signal; and a filter included in said carrier recovery network for filtering baseband and near-baseband video signals, said filter exhibiting a response including significant amplitude attenuation at a prescribed frequency for attenuating .narrowband interferer signal components subject to contaminating said received signal.

Claim 8

Apparatus according to claim 5, wherein said filter is a digital FIR filter exhibiting substantially zero throughput delay.

Claim 9

Apparatus according to claim 5, wherein said received signal is a television signal subject to being contaminated by co-channel interference; and said filter provides significant attenuation at NTSC picture carrier and chrominance carrier frequencies.

Claim 10

In a system for receiving a signal representative of digital video information, apparatus comprising: an input processor; an input equalizer responsive to signals from said input processor; a carrier recovery network responsive to an output signal from said equalizer for providing a demodulated baseband video signal; an output signal processor for processing said baseband video signal; and a filter included in said carrier recovery network for filtering baseband and near-baseband video signals, said filter exhibiting a response including significant amplitude atenuation at a prescribed frequency for attenuating narrowband interferer signal components subject to contaminating said received signal; wherein said carrier recovery network comprises a feedback control loop including said filter.

Claim 11

In a system for receiving a signal representative of digital video information, apparatus comprising: an input processor; an input equalizer responsive to signals from said input processor; a carrier recovery network responsive to an output signal from said equalizer for providing a demodulated baseband video signal; an output signal processor for processing said baseband video signal; and a filter included in said carrier recovery network for filtering baseband and near-baseband video signals, said filter exhibiting a response including significant amplitude atenuation at a prescribed frequency for attenuating narrowband interferer signal components subject to contaminating said received signal; wherein said carrier recovery network comprises a feedback control loop including said filter.

Claim 12

In a system for receiving a signal representative of digital video information, apparatus comprising: an input processor; an input equalizer responsive to signals from said input processor; a carrier recovery network responsive to an output signal from said equalizer for providing a demodulated baseband video signal; an output signal processor for processing said baseband video signal; and a filter included in said carrier recovery network for filtering baseband and near-baseband video signals, said filter exhibiting a response including significant amplitude attenuation at a prescribed frequency for attenuating narrowband interferer signal components subject to contaminating said received signal; wherein said carrier recovery network includes a slicer with an input for receiving signals from said filter, and an output; and a decision feedback equalizer has an input for receiving output signals from said slicer and an output coupled to a point in said carrier recovery network prior to said slicer.

Claim 13

In a system for receiving a signal representative of digital video information, apparatus comprising: an input processor; an input equalizer responsive to signals from said input processor; a carrier recovery network responsive to an output signal from said equalizer for providing a demodulated baseband video signal; an output signal processor for processing said baseband video signal; and a filter included in said carrier recovery network for filtering baseband and near-baseband video signals, said filter exhibiting a response including significant amplitude attenuation at a prescribed frequency for attenuating narrowband interferer signal components subject to contaminating said received signal; wherein said carrier recovery network includes a slicer with an input for receiving signals from said filter, and an output; and a decision feedback equalizer has an input for receiving output signals from said slicer and an output coupled to a point in said carrier recovery network prior to said slicer.

Claim 14

In a system for receiving a signal representative of digital video information, apparatus comprising: an input processor; an input equalizer responsive to signals from said input processor; a carrier recovery network responsive to an output signal from said equalizer for providing a demodulated baseband video signal; an output signal processor for processing said baseband video signal; and a filter included in said carrier recovery network for filtering baseband and near-baseband video signals, said filter being a digital FIR filter with substantially zero throughput delay and exhibiting a response including significant amplitude attenuation at a prescribed frequency for attenuating narrowband interferer signal components subject to contaminating said received signal; wherein said carrier recovery network includes a rotator responsive to output signals from said equalizer; a slicer responsive to output signals from said rotator; an error detector coupled to said slicer for providing an output error signal representing a phase error; and a phase control network responsive to input and output signals of said slicer; and wherein said filter is coupled between said rotator and said slicer for filtering output signals from said rotator.

Claim 15

In a system for receiving a signal representative of digital video information, apparatus comprising: an input processor; an input equalizer responsive to signals from said input processor; a carrier recovery network responsive to an output signal from said equalizer for providing a demodulated baseband video signal; an output signal processor for processing said baseband video signal; and a filter included in said carrier recovery network for filtering baseband and near-baseband video signals, said filter being a digital FIR filter with substantially zero throughput delay and exhibiting a response including significant amplitude attenuation at a prescribed frequency for attenuating narrowband interferer signal components subject to contaminating said received signal; wherein said carrier recovery network includes a rotator responsive to output signals from said equalizer; a slicer responsive to output signals from said rotator; an error detector coupled to said slicer for providing an output error signal representing a phase error; and a phase control network responsive to input and output signals of said slicer; and wherein said filter is coupled between said rotator and said slicer for filtering output signals from said rotator.

Claim 16

In a system for receiving a television signal including a component representative of digital video information, apparatus comprising: an input processor; a feed-forward equalizer responsive to signals from said input processor; and a carrier recovery network responsive to an output signal from said equalizer for providing a demodulated baseband video signal, said carrier recovery network comprising a carrier recovery control loop including (a) a rotator responsive to output signals from said forward equalizer; (b) a filter for filtering output signals from said rotator, said filter exhibiting significant attenuation of at least one of baseband picture carrier and chrominance carrier frequencies; (c) a slicer responsive to output signals from said filter; (d) an error detector coupled to said slicer for providing a phase error signal; and (e) a phase control network having an input responsive to an output signal from said slicer, and an output coupled to said rotator.

Claim 17

In a system for receiving a television signal including a component representative of digital video information, apparatus comprising: an input processor; a feed-forward equalizer responsive to signals from said input processor; and a carrier recovery network responsive to an output signal from said equalizer for providing a demodulated baseband video signal, said carrier recovery network comprising a carrier recovery control loop including (a) a rotator responsive to output signals from said forward equalizer; (b) a filter for filtering output signals from said rotator, said filter exhibiting significant attenuation of at least one of baseband picture carrier and chrominance carrier frequencies; (c) a slicer responsive to output signals from said filter; (d) an error detector coupled to said slicer for providing a phase error signal; and (e) a phase control network having an input responsive to an output signal from said slicer, and an output coupled to said rotator.

Claim 18

Apparatus according to claim 11 and further including a feedback equalizer having a signal input responsive to an output signal from said slicer, a control input responsive to said error signal, and an output coupled to an input of said slicer; and wherein said feed-forward equalizer is also responsive to said error signal.

Claim 19

Apparatus according to claim 11, wherein said received television signal is a Pulse Amplitude Modulated (PAM) signal.