| 摘要 |
PROBLEM TO BE SOLVED: To reduce the possibility that controlled sound or controlled vibration gets into a periodically varying state. SOLUTION: A divergence suppressing coefficientβk for a rotational frequency band which includes the rotational frequency of an engine is increased in a step 203, while when a drive signal (y) is decided to be in a periodically varying state and if decision by a step 204 is 'yes', or if the rotational frequency of the engine has passed through a plurality of rotational frequency bands while detection is being performed for periodical variation, not only the divergence suppressing coefficientβk for the rotational frequency band including the rotational frequency of the engine but also divergence suppressing coefficients for other rotational frequency bands neighboring this rotational frequency band are changed. Specifically, each of divergence suppressing coefficients for the plurality of rotational frequency bands is made to conform to the largest value of them.
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