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Multiplexer-related

Low-complexity-frequency-estimator-and-interference-cancellation-method-and-device

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Details

Inventors: Thomson, Larry S.; Alelyunas, Carl H.;
Assignee: 3Com Corporation (Santa Clara, CA)
Primary Examiner: Chin; Stephen
Assistant Examiner: Fan; Chieh M.
Attorney, Agent or Firm: McDonnell Boehnen Hulbert & Berghoff

A method and apparatus for estimating the frequency of a periodic signal and for canceling the interference in a modem signal. Power line noise may interfere with electronic signals. Since power lines may be either 50 Hz or 60 Hz, depending on the country, frequency estimation of the periodic power line noise is necessary. Modem signals are received and autocorrelated in order to identify the periodic characteristics of the signal over time. Once the frequency is identified, the power line noise is modeled based on creating a circular buffer. Initially, the circular buffer is composed of scaled samples of one cycle of the fundamental frequency of the power line noise. Thereafter, samples are received, scaled, and combined with previous buffer values in order to update the buffer. In this manner, the buffer models the power line noise, so that the power line noise may be removed from the system.

DETAILED DESCRIPTION In a first aspect of the invention, a method and apparatus is provided for identifying the frequency of a periodic signal within an electronic signal by treating the periodic signal as the primary signal and by treating the remaining portion of the electronic signal as background noise, uncorrelated with the periodic signal.
In a second aspect of the invention, a method and apparatus is provided for modeling and reducing periodic noise from an electronic signal.
The periodic noise is treated as the primary signal and the remaining portion of the electronic signal is treated as background noise, uncorrelated with the periodic signal.
It is an object of the present invention to provide a method and apparatus for determining the frequency of a periodic signal.
It is a further object of the present invention to provide a method and apparatus for removing periodic interference, such as power line noise, from an electronic signal.

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