ACTIVE SOUND AND/OR VIBRATION CONTROL

摘要

An active sound or vibration control system for compensating noise or vibration arising from a periodic source of changing periodicity, wherein sensors (6) sense the existing noise and vibration, the sensor signals are sampled several times per cycle by an ADC (8) triggered by a signal output from a sensor (3) detecting the position of the source in its cycle, the sampled signals are transformed into compensation actuator drive signal values by a series of transform and adaptation modules (11 to 13, 15) based on algorithms dependent on the frequency of the source, and the drive signal values are stored in a memory means (1) continually updated by the values derived from the sampled sensor signals.