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Method and apparatus for combating impulse noise in digital communications channels

  • US 6,647,070 B1
  • Filed: 09/09/1999
  • Issued: 11/11/2003
  • Est. Priority Date: 09/10/1998
  • Status: Expired due to Term
First Claim
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1. A digital receiver, comprising:

  • a demodulator for receiving an input data signal, down converting said signal, and sampling said signal to provide an input data stream, a smoother for receiving said input data stream, identifying data samples that are likely contaminated by impulse noise, and attenuating data samples likely contaminated by impulse noise, a filter and timing recovery portion for applying a square-root raised cosine filter to data samples output by said smoother and for determining the sample rate and sample clock phase, a filter for filtering the output from said filter and timing recovery portion having an impulse response sequence with a small peak to average ratio that attenuates the effect of impulse noise with a duration less than the duration of a symbol, an adaptive equalizer for receiving the output of said filter and compensating for carrier phase, undesired inter-symbol interference, and stationary noise components, a modified maximum likelihood sequence estimation (MLSE) decoder for applying a viterbi MLSE using a plurality of non-zero taps to determine a sequence of symbols in a data stream received from said adaptive equalizer, and a forward error correction (FEC) decoder that utilizes indications of samples contaminated with noise from said smoother to perform error correction on said data stream.

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