ADAPTIVE SIGNAL EQUALIZER WITH ADAPTIVE ERROR TIMING AND PRECURSOR/POSTCURSOR CONFIGURATION CONTROL

• US 20070230557A1
• Filed: 06/07/2007
• Published: 10/04/2007
• Est. Priority Date: 11/08/2002
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Scintera Networks LLC (Analog Devices, Inc.)
• Inventors: Shanbhag, Abhijit, Yu, Qian, Phanse, Abhijit, Balasubramonian, Venugopal, Ibragimov, Edem, Mukherjee, Debanjan, Bhattacharjee, Jishnu
• Granted Patent: US 7,421,021 B2
• Time in Patent Office: Days
• US Class Current: 375/234
• CPC Class Codes: H03H 2021/0096 with input-sampling frequency and output-delivery frequency which differ, e.g. extrapolation; anti-aliasing
• CPC Class Codes: H03H 21/0012 Digital adaptive filters
• CPC Class Codes: H04L 2025/0349 as a feedback filter
• CPC Class Codes: H04L 2025/03611 Iterative algorithms
• CPC Class Codes: H04L 25/03057 with a recursive structure H04L25/03031 takes precedence
• CPC Class Codes: H04L 7/0029 interpolation of received data signal
• CPC Class Codes: H04L 7/0062 detection of error based on data decision error, e.g. Mueller type detection
• CPC Class Codes: H04L 7/0079 Receiver details

Abstract

An adaptive signal equalizer with a feedforward filter in which the feedback error signal and corresponding incoming data signal are dynamically aligned in time using signal interpolation, and further, to control the precursor/postcursor filter taps configuration, thereby producing more adaptive filter tap coefficient signals for significantly improved and robust signal equalization.

Claims

1. An apparatus including an adaptive signal equalizer, comprising:

adaptive equalization circuitry that receives at least a plurality of adaptive coefficient signals and in response thereto receives and equalizes an input data signal to provide an equalized signal;

signal slicer circuitry, coupled to said adaptive equalization circuitry, that receives and slices said equalized signal to provide a sliced signal and a difference signal corresponding to a difference between said equalized signal and said sliced signal; and

adaptive coefficient signal generator circuitry, coupled to said signal slicer circuitry and said adaptive equalization circuitry, that

receives said plurality of adaptive coefficient signals,

receives said input data signal and said difference signal and processes said plurality of adaptive coefficient signals and one of said input data signal and said difference signal to provide first and second aligned signals which are substantially temporally aligned, and

processes said first and second aligned signals together to provide said plurality of adaptive coefficient signals.

2. The apparatus of claim 1, wherein said adaptive equalization circuitry comprises fractionally spaced linear transversal equalizer circuitry.

3. The apparatus of claim 1, wherein said signal slicer circuitry comprises:

signal comparison circuitry that receives and compares said equalized signal against a reference signal to provide said sliced signal; and

signal combining circuitry, coupled to said signal comparison circuitry, that receives and combines said equalized signal and said sliced signal to provide said difference signal.

16. The apparatus of claim 1, wherein said adaptive equalization circuitry comprises:

feedforward filter circuitry that receives said plurality of adaptive coefficient signals and in response thereto receives and processes said input data signal to provide a feedforward processed signal;

feedback filter circuitry, coupled to said signal slicer circuitry, that receives and processes said sliced signal to provide a feedback processed signal; and

signal combining circuitry, coupled to said feedforward filter circuitry, said feedback filter circuitry and said signal slicer circuitry, that receives and combines said feedforward and feedback processed signals to provide said equalized signal.

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17. An apparatus including an adaptive signal equalizer, comprising:

adaptive equalizer means for receiving at least a plurality of adaptive coefficient signals and in response thereto receiving and equalizing an input data signal and providing an equalized signal;

signal slicer means for slicing said equalized signal and providing a sliced signal and a difference signal corresponding to a difference between said equalized signal and said sliced signal; and

adaptive coefficient signal generator means for

processing said plurality of adaptive coefficient signals and one of said input data signal and said difference signal and providing first and second aligned signals which are substantially temporally aligned, and

processing said first and second aligned signals together and providing said plurality of adaptive coefficient signals.

26. The apparatus of claim 17, wherein said adaptive equalizer means comprises:

feedforward filter means for processing said input data signal in response to said plurality of adaptive coefficient signals and providing a feedforward processed signal;

feedback filter means for processing said sliced signal and providing a feedback processed signal; and

signal combiner means for combining said feedforward and feedback processed signals and providing said equalized signal.

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27. A method for adaptive signal equalizing, comprising:

receiving at least a plurality of adaptive coefficient signals and in response thereto receiving and equalizing an input data signal to generate an equalized signal;

slicing said equalized signal to generate a sliced signal and a difference signal corresponding to a difference between said equalized signal and said sliced signal;

processing said plurality of adaptive coefficient signals and one of said input data signal and said difference signal to generate first and second aligned signals which are substantially temporally aligned; and

processing said first and second aligned signals together to generate said plurality of adaptive coefficient signals.

28. The method of claim 27, wherein said receiving at least a plurality of adaptive coefficient signals and in response thereto receiving and equalizing an input data signal to generate an equalized signal comprises linearly equalizing said input data signal using a plurality of fractionally spaced signal delays.

29. The method of claim 27, wherein said slicing said equalized signal to generate a sliced signal and a difference signal corresponding to a difference between said equalized signal and said sliced signal comprises:

comparing said equalized signal against a reference signal to generate said sliced signal; and

combining said equalized signal and said sliced signal to generate said difference signal.

30. The method of claim 27, wherein:

said processing one of said input data signal and said difference signal to generate first and second aligned signals which are substantially temporally aligned comprises interpolating said one of said input data signal and said difference signal to generate an interpolated delayed signal; and

said processing said first and second aligned signals together to generate said plurality of adaptive coefficient signals comprises combining said interpolated delayed signal and another of said input data signal and said difference signal to generate said plurality of adaptive coefficient signals.

40. The method of claim 30, wherein said combining said interpolated delayed signal and another of said input data signal and said difference signal to generate said plurality of adaptive coefficient signals comprises:

delaying said first aligned signal to generate a plurality of delayed signals;

multiplying said first aligned signal, said plurality of delayed signals and said second aligned signal to generate a plurality of product signals; and

integrating said plurality of product signals to generate a plurality of integrated signals as said plurality of adaptive coefficient signals.

41. The method of claim 30, wherein said combining said interpolated delayed signal and another of said input data signal and said difference signal to generate said plurality of adaptive coefficient signals comprises:

delaying said one of said input data signal and said difference signal to generate a plurality of delayed signals;

multiplying said one of said input data signal and said difference signal, said plurality of delayed signals and said another of said input data signal and said difference signal to generate a plurality of product signals; and

integrating said plurality of product signals to generate a plurality of integrated signals as said plurality of adaptive coefficient signals.

42. The method of claim 27, wherein said receiving at least a plurality of adaptive coefficient signals and in response thereto receiving and equalizing an input data signal to generate an equalized signal comprises:

processing said input data signal in response to said plurality of adaptive coefficient signals to generate a feedforward processed signal;

processing said sliced signal to generate a feedback processed signal; and

combining said feedforward and feedback processed signals to generate said equalized signal.

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