ACTIVE NOISE CONTROL SYSTEM FOR AUTOMOTIVE VEHICLE

摘要

An active noise control system includes a plurality of vibration pickups for detecting of physical quantities of noise sources, such as vibrations of suspension members of a vehicle, and a plurality of microphones for detecting residual noises transmitted to observing positions. The output signals of the vibration pickups are added up by means of an adder to be input to a controller. The active noise control system also includes a plurality of delay circuits for applying delay times to the respective output signals of the vibration pickups so as to essentially equalize transmitting time of one of the output signals with that of the other output signals. The output signals of the microphones are input to the controller independently of each other. The controller outputs drive signals to a plurality of loudspeakers independent of each other to cause the loudspeakers to produce control sounds so that the control sounds interfere with the noises transmitted from the noise sources to decrease the noises transmitted to the observing positions.