Patent ID: 8369901

Claim:
A signal processing system, comprising a plurality of microphones and loudspeakers; a hands-free set configured to receive a telephone signal from a remote party and to transmit a microphone signal supplied by at least one of the microphones to the remote party; an in-vehicle communication system configured to: receive the microphone signal supplied by at least one of the microphones; receive the telephone signal; amplify the microphone signal to obtain at least one first output signal; output the at least one first output signal and/or a second output signal corresponding to the telephone signal to at least one of the loudspeakers; wherein the signal processing system is configured to detect speech activity in the telephone signal and to control the in-vehicle communication system to reduce amplification of the microphone signal, if it is detected that speech activity is present in the telephone signal, wherein the hands-free set comprises an adaptive echo compensation filtering system and is configured to adapt the filter coefficients of the echo compensation filtering system only when the at least one first output signal output by the in-vehicle communication system is reduced to a predetermined level and wherein the in-vehicle communication system is configured to receive multiple microphone signals in multiple channels and to amplify the multiple microphone signals to obtain multiple first output signals and further comprising: a power estimating module configured to estimate the short-time power density of the multiple first output signals and to supply the maximum of the short-time power densities of the multiple first output signals to the hands-free set; and wherein the hands-free set is configured to determine whether the at least one first output signal output by the in-vehicle communication system is reduced to the predetermined level based on the maximum of the short-time power densities of the multiple first output signals.