| 摘要 |
PROBLEM TO BE SOLVED: To provide a loudspeaker system with a built-in adaptive howling canceller capable of detecting a change in an acoustic characteristic with high accuracy and effectively preventing howling. SOLUTION: A positional information control section 11 detects a distance between a microphone 1 and a speaker 7. A delay circuit 8 and an adaptive filter 9 receive the detected positional information. The delay circuit 8 estimates a time delay of a feedback sound signal from the speaker 7 to the microphone 1 on the basis of the positional information, attaches a delay to the signal from the microphone 1 and gives the resulting signal to the adaptive filer 9. The adaptive filter 9 outputs a simulated feedback sound signal from the received signal attached with the delay and subtracts the simulated signal from the signal received from the microphone 1. Moreover, an adaptive algorithm of the adaptive filter 9 is selected to update a filter coefficient in response to a change in the distance between the microphone 1 and the speaker 7. Thus, the adaptive howling canceller can effectively prevent howling. COPYRIGHT: (C)2006,JPO&NCIPI |
