Noise reduction by a loud speaker based on self-sensing actuation

摘要

A study on noise reduction or noise cancellation has been concerned widely from the environmental point of view. Active noise control is very effective in such problem where noise reduction is attained by a canceling speaker driven by the feedback signal from a pick up microphone in the noise field. In this paper, a quite new technique for active noise reduction control is proposed taking notice of electromechanical duality of a loud speaker, that is, selfsensing actuation of a loud speaker. A single loud speaker unit is capable concurrently to sense sound radiation and to actuate sound vibration in the control lop with use of a bridge circuit that can distinguish the sensor voltage from the actuation voltage.