Patent ID: 6442272
Filing Date: 2002-08-27
Classification: H04M

Abstract:
A teleconferencing apparatus, comprising:a receive-input terminal connected to receive telecommunication signals from a far-end source; a first loudspeaker connected with the receive-input terminal for producing a near-end acoustic signal in response to the telecommunication signals from the far-end; a send-output terminal connected to transmit telecommunication signals to the far-end; an echo canceller connected between the receive-input terminal and the receive output terminal, the echo canceller having a send-input terminal and a characteristic tail length; a first microphone positioned relative to the first loudspeaker such that the acoustic delay time between the first loudspeaker and the first microphone is less than or equal to the tail length of the echo canceller; a second microphone positioned relative to the first loudspeaker such that the acoustic delay time between the first loudspeaker and the second microphone is greater than the tail length of the echo canceller; a mixer connected with the first microphone and with the second microphone for mixing respective microphone signals generated by the first and second microphones, and connected to provide a mixed signal to the send-input terminal of the echo canceller; a gate connected between the second microphone and the mixer for selectively providing signals from the second microphone to the mixer during periods of near-end speech.