| 摘要 |
<P>PROBLEM TO BE SOLVED: To always realize a normal adaptive operation. <P>SOLUTION: In order to negate noise transmitting through an exhaust duct 1 with an acoustic wave emitted from a secondary sound source loudspeaker, a Filtered-x LMS algorithm executing part 8 controls the transfer function W of a filter 3 so that the composite transfer function of the transfer function W of an FIR adaptive digital filter 3 and a transfer function C occurring between the filter 3 and an error microphone 6 becomes equal to the transfer function P of the exhaust duct 1. In order to constitute its control system from a Filtered-x LMS algorithm, the amplitude or the phase of the transfer function CI of an FIR digital filter 7 with an identified transfer function C is changed until it becomes equal to the transfer function C when the transfer function C is changed. <P>COPYRIGHT: (C)2003,JPO |
