US 5,706,057 A · Phase detector in a carrier recovery network for a vestigial sideband signal

Abstract

A television signal receiver for processing an HDTV signal transmitted in a vestigial sideband (VSB) format with a one-dimensional data constellation includes a first carrier recovery network (18), an equalizer (20), and a second carrier recovery network (22, 30, 62). A multiple stage quantizer network (50, 66) exhibiting progressively finer resolution is associated with the operation of the equalizer for providing blind equalization without need of a "training" signal. The second carrier recovery network includes a phase detector (30) wherein a one-symbol delayed (312) input signal and a quantized (310) input signal are multiplied (316), and an unquantized input signal and a quantized (310) one-symbol delayed (314) input signal are multiplied (316), and an unquantized input signal and a quantized (310) one-symbol delayed (314) input signal are multiplied (318). Signals produced by the multiplication are subtractively combined (320) to produce an output signal representing carrier phase error.

Claims7

Dependent claims

In a system for receiving a vestigial sideband (VSB) video signal formatted as a one-dimensional constellation of data symbols representing digital image data and subject to exhibiting a carrier offset, apparatus comprising:

a carrier recovery network (22,30) for shifting said received VSB signal toward baseband;
and
a phase detector (32) in said carrier recovery network, including
an input for receiving a near baseband VSB signal;
a quantizer (310) responsive to said input VSB signal for producing a quantized VSB signal;
a symbol delay network (312,314) for delaying said input VSB signal and for delaying said quantized signal;
a first multiplier (316) responsive to said quantized VSB signal and to a symbol delayed signal from said delay network, for producing a first signal;
a second multiplier (314) responsive to said input VSB signal and to a symbol delayed quantized signal from said delay network, for producing a second signal;
and
a combiner for subtractively combining said first and second signals to produce a phase error representative signal.

7 more elements

Dependencies are inferred from the claim text.

Phase detector in a carrier recovery network for a vestigial sideband signal

Life of this patent

Phase detector in a carrier recovery network for a vestigial sideband signal

Life of this patent

Abstract

Claims7