Motorola Corporation

Continental Automotive Systems Corporation

Kyle K Iwai

James Brian Piket

Daniel S Rokusek

David L Barron

Received data is filtered to produce pre-noise suppression data. Noise is removed from the pre-noise suppression data to provide noise-suppressed data. At least one weighted filter coefficient is dynamically determined using at least the pre-noise suppression data and not the noise suppressed data. The determination occurs independently from and is not affected by removing the noise from the pre-noise suppression data. Removing the noise from the pre-noise suppression data occurs independently from and is not affected by dynamically determining the at least one weighted coefficient.

Echo canceler circuit and method

A method for reducing a computational complexity of an m-stage adaptive filter is provided by updating recursively forward and backward error prediction square terms for a first portion of a length of the adaptive filter, and keeping the updated forward and backward error prediction square terms constant for a second portion of the length of the adaptive filter.

Reduced complexity recursive least square lattice structure adaptive filter by means of limited recursion of the backward and forward error prediction squares

An echo canceller circuit () and method performs cascaded echo cancellation and noise suppression in a non-interfering manner. The echo canceller circuit () includes pre-noise suppression logic (), echo canceller coefficient logic (), noise suppression logic () and an echo canceller filter (). The pre-noise suppression logic () receives pre-echo canceller uplink data () and downlink data (), and in response produces pre-noise suppression uplink data (). The echo canceller coefficient logic () receives the pre-noise suppression uplink data () and the pre-echo canceller uplink data (), and in response produces filter coefficient data (). The noise suppression logic () receives the pre-noise suppression uplink data (), and in response produces noise suppressed uplink data (). The echo canceller filter () receives the noise suppressed uplink data () and the filter coefficient data () and in response produces final uplink data ().

A downlink activity and double talk probability detector and method for an echo canceler circuit () improves the stability of an echo canceler adaptive filter () and improves the attenuation of post-echo canceler uplink data (). The echo canceler circuit () includes a downlink activity and double talk probability data generator () and an echo canceler stage (). The downlink activity and double talk probability data generator () receives pre-echo canceler uplink data () and downlink data () and in response produces double talk probability data () and downlink activity data (). The echo canceler stage () receives the downlink data (), the pre-echo canceler uplink data (), the double talk probability data () and the downlink activity data (), and in response produces uplink data ().

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Chandler, AZ, United States of America

Kyle K Iwai