JPS647798A - Noise-exclusion telephone set with microphone supporter - Google Patents

Abstract

PURPOSE:To output only a voice desired to be transmitted to the opposite party by providing a microphone to collect sound from a telephone set in the vicinity of the telephone set and providing another microphone to collect noise from a noise source distant from the telephone set, and outputting the outputs from said microphones via a noise eliminating circuit and a telephone circuit. CONSTITUTION:The telephone set is disposed in a position B, and the microphone to collect the voice of a speaker is disposed in a position C, 4cm distant from the position B, and the other microphone to collect sound from the noise source existing in a position A about 10m distant is disposed in a position D in the vicinity of the former microphone. Respective outputs from the microphones are inputted to a sound-electric transducer 114, whose output is amplified by amplifiers 1, 2, then transmitted to a noise elimination circuit 3. Thereafter, an output from the circuit 3 is outputted from a terminal G through the telephone circuit 4. By such a constitution, in the circuit 3 which is the major circuit, the polarity of an electrical signal inputted to its plus terminal is made the same polarity as an electrical signal outputted from its output terminal, but a signal inputted to the minus terminal is made the opposite polarity, so that noise component is offset.