The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 28, 1999
Filed:
Mar. 25, 1997
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A counter increments a count value every given time period. An adaptive operation control unit selects channels in which adaptive operations are done from all the channels in obedience to the count value to output produced selection signals to AND circuits. Double-talk detection circuits judge the presence/absence of a double-talk state and output detection signals to the AND circuits. The AND circuits operate logical AND of the selection signals and the detection signals and output the logical AND results as control signals to filter coefficient updating circuits. The filter coefficient updating circuits update or do not update filter coefficients stored in FIR filter units according to the control signals. The FIR filter units produce echo replicas by calculating convolutions of the filter coefficients and the receive signals. Subtractors subtract the echo replicas from transmission signals to output residual signals.