초록 ▼

A double talk detector for echo cancellers monitors the ratio of four wire transmit in energy to transmit out energy (ERLE), along with the change and direction of change of an estimated impulse response, to control updating of the estimated inpulse response. When the ERLE is low and the directional

A double talk detector for echo cancellers monitors the ratio of four wire transmit in energy to transmit out energy (ERLE), along with the change and direction of change of an estimated impulse response, to control updating of the estimated inpulse response. When the ERLE is low and the directional change of the impulse response is high, indicating an end path switch, the double talk detector enables the estimated impulse response to be updated. If the directional change of the impulse response and the ERLE are both low, indicating the occurrence of double talk, the detector inhibits updating of the impulse response until either the ERLE becomes sufficiently high, indicating single talk, or the directional change of the impulse response becomes sufficiently large, indicating an inconverged state of the canceller. The arrangement allows convergence of the echo canceller to be properly controlled both in response to double talk and to changes in the impulse response of the end path.

대표청구항 ▼

A double talk detector for controlling convergence of an adaptive filter, wherein the adaptive filter is for being coupled to transmit and receive paths for separating the transmit path into transmit in and transmit out paths, for developing and periodically updating an adjustable estimated impulse

A double talk detector for controlling convergence of an adaptive filter, wherein the adaptive filter is for being coupled to transmit and receive paths for separating the transmit path into transmit in and transmit out paths, for developing and periodically updating an adjustable estimated impulse response h[n]of an end path and for generating, in accordance with the estimated impulse response and a receive path signal, an estimate of an echo signal occurring on the transmit in path in response to the receive path signal, which echo estimate signal is algebraically combined with a transmit in path signal to yield a transmit out path signal, said double talk detector comprising an echo return loss enhancement (ERLE) detector for generating an ERLE signal having a value in accordance with the ratio of transmit in signal energy to transmit out signal energy; an end path switch detector for developing a DD