Equalizers for layered modulated and other signals

• US 7,583,728 B2
• Filed: 01/22/2007
• Issued: 09/01/2009
• Est. Priority Date: 10/25/2002
• Status: Expired due to Term

• Current Assignee: DIRECTV, LLC (AT&T, Inc.)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Inventors: Chen, Ernest C., Lin, Tung-Sheng, Lindsey, William C., Wang, Weizheng
• Primary Examiner(s): Bayard; Emmanuel
• Application Number:
  US11/656,662
• Publication Number:
  US 20070116108A1
• Time in Patent Office: 953 Days
• Field of Search: 375229-234
• US Class Current: 375/229
• CPC Class Codes: H04L 2025/03401 PSK
• CPC Class Codes: H04L 2025/0342 QAM
• CPC Class Codes: H04L 2025/0349 as a feedback filter
• CPC Class Codes: H04L 25/03019 adaptive, i.e. capable of adjustment during data reception
• CPC Class Codes: H04L 27/3488 Multiresolution systems

Abstract

A method and apparatus for equalizing digital data signals is disclosed. The method comprises the steps of demodulating and decoding an input signal having input data to produce a data output, remodulating the data output to produce a training sequence including an idealized input signal, wherein the training sequence is comprised of adjacent symbols in the input data, and generating equalizer parameters from the training sequence. The apparatus comprises a demodulator (for demodulating an input signal to produce a data output), a modulator communicatively coupled to the demodulator (for remodulating the data output to produce a training sequence including an idealized input signal wherein the training sequence is comprised of adjacent symbols in the input data), and a parameter generation module communicatively coupled to the modulator (for generating equalizer parameters from the training sequence).

Claims

1. A blanket equalizer for equalizing digital data signals, comprising:

a distributed feedback equalizer for accepting an input signal, the distributed feedback equalizer comprising;

a feedforward transversal filter for filtering the input signal;

a first adder having a first input coupled to the feedforward transversal filter, a second input, and an output having the sum of the first input and the second input;

a symbol detector, having an input coupled to the output of the first adder and an output providing detected symbols;

a feedback transversal filter, having an input coupled to the symbol detector output, and an output coupled to the first adder second input;

a third transversal filter, coupled to the symbol detector for receiving the detected symbols and for filtering the detected symbols; and

a second adder for summing an input signal and the filtered detected symbols from the third transversal filter to create an estimated symbol sequence.

2. The blanket equalizer of claim 1, wherein the input signal is filtered by a matched filter having an output and the matched filter'"'"'s output is input to the second adder.