Adaptive line enhancer

US4238746A · kind A · utility

Assignee

• United States of America as represented by the Secretary of the Air Force · US

Inventors

• John M. McCool · El Cajon, US
• Bernard Widrow · Stanford, US
• James R. Zeidler · San Diego, US
• Robert H. Hearn · Burns Lake, CA
• Douglas M. Chabries · Salem, US

Key dates

• Filing date: Mar 20, 1978
• Grant date: Dec 9, 1980
• Expiry date: Mar 20, 1998

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03H21/00
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An input signal X(j) is fed directly to the positive port of a summing function and is simultaneously fed through a parallel channel in which it is delayed, and passed through an adaptive linear transversal filter, the output being then subtracted from the instantaneous input signal X(j). The difference, X(j)-Y(j), between these two signals is the error signal .epsilon.(j). .epsilon.(j) is multiplied by a gain .mu. and fed back to the adaptive filter to readjust the weights of the filter. The weights of the filter are readjusted until .epsilon.(j) is minimized according to the recursive algorithm: ##EQU1## where the arrow above a term indicates that the term is a signal vector. Thus, when the means square error is minimized, W.sub.(j+1) =W.sub.(j), and the filter is stabilized.