Dual mode QAM/VSB receiver
First Claim
1. A carrier recovery apparatus, comprising:
- a first demultiplexer to generate a sampled first phase symbol and a first phase mid-symbol based on an input signal, wherein the sampled first phase symbol is sampled at a first sampling time and the first phase mid-symbol is sampled at a second sampling time;
a first decision device block to generate a first phase symbol decision based upon the sampled first phase symbol;
a first adder to combine the first phase symbol decision and the sampled first phase symbol to produce a first error term;
a first multiplier to multiply the first error term and a second phase mid-symbol to produce a first phase error term, wherein the second phase mid-symbol is sampled at the first sampling time; and
means for generating a timing reference signal based on the first phase error term.
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Accused Products
Abstract
A television receiver system capable of receiving and demodulating television signal information content that has been modulated and transmitted in accordance with a variety of modulation formats is disclosed. In particular, the system is able to accommodate receipt and demodulation of at least 8 and 16-VSB modulated signals in order to support US HDTV applications, as well as 64 and 256-QAM modulated signals, for European and potential US CATV implementations. The system includes carrier and timing recovery loops adapted to operate on an enhanced pilot signal as well as decision directed carrier phase recovery loops. Phase detectors operate on I and Q rail signals, or generate a Q rail from a Hilbert transform of the I rail. Decision directed loops incorporate a trellis decoder in order to operate on sequence estimated decisions for improved reliability in poor SNR environments.
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Citations
9 Claims
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1. A carrier recovery apparatus, comprising:
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a first demultiplexer to generate a sampled first phase symbol and a first phase mid-symbol based on an input signal, wherein the sampled first phase symbol is sampled at a first sampling time and the first phase mid-symbol is sampled at a second sampling time; a first decision device block to generate a first phase symbol decision based upon the sampled first phase symbol; a first adder to combine the first phase symbol decision and the sampled first phase symbol to produce a first error term; a first multiplier to multiply the first error term and a second phase mid-symbol to produce a first phase error term, wherein the second phase mid-symbol is sampled at the first sampling time; and means for generating a timing reference signal based on the first phase error term. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification