Noise reducing receiver device

Abstract

The present invention is concerned with a receiver device for converting electrical signal from a headphone, a telephone receiver or the like into acoustic signals. More particularly, it relates to a noise reducing receiver device in which acoustic signals in the vicinity of an electro-acoustic transducer element are converted by a microphone into electrical signals and negatively fed back to an amplifier circuit which is adapted for amplifying input electrical signals and supplying the amplified signals to the electro-acoustic transducer element. In the noise reducing receiver device, the input electrical signals are amplified by the amplifier circuit and converted by the electro-acoustic transducer element into output acoustic signals. A microphone is arranged in the vicinity of the electro-acoustic transducer element and adapted for converting the output acoustic signals and external noise into electrical signals, which are negatively fed back to the amplifier circuit via a feedback circuit. The output acoustic signals may be heard at a desired noise reduction level by adjusting the transfer function H of the electro-acoustic transducer element, the transfer function A of the amplifier circuit, the transfer function M of the microphone and the transfer function .beta. of the feedback circuit within a range determined by .vertline.AHM.beta..vertline.>>1.