| 摘要 |
PURPOSE:To reduce the time required for the initial training by detecting a connected microphone so as to apply the initial training only to the connected microphone. CONSTITUTION:A connected microphone detection circuit 15 prior to the talking measures a noise level in a room so as to discriminate the presence of connection of a microphone depending on the presence of the noise in the room. The connection microphone detection circuit 15 sends the result of detection to a training control circuit 16. The training control circuit 16 turns on a switch A to operate a training signal source 5, selects sequentially the connected microphones, an estimate circuit 6 obtains a sample string of the estimated impulse response of the echo path from the speaker 2 till the microphone and stores it in a storage circuit 12. Since the training of all paths is not applied in this way, the time required for the training is reduced. |
