CIRCUIT ELIMINATING NOISE GIVING DISTURBANCE ONTO AUDIO FREQUENCY OF AUDIBLE FREQUENCY AMPLIFIER DUE TO EXTERNAL HIGH FREQUENCY AND/OR INTERNAL HIGH FREQUENCY SIGNAL

摘要

PROBLEM TO BE SOLVED: To ensure reproduction of a clear sound by connecting a simple filter to an externally connected part including audio frequency amplifier input output terminals and AC power supply directly or externally. ;SOLUTION: A filter 3 to eliminate the entire frequency band of a disturbing high frequency signal RF is connected electrically to a radio transmitter-receiver or an electronic device 1 such as an audio equipment represented only by an audible frequency amplifier 2 for audio signal conversion. For example, the filter 3 consisting of a capacitor C and a choke coil L is directly connected to an amplifier 2 on a common chassis of the small sized electronic device 1. Thus, external or internally generated disturbing high frequency RF masking an audible audio frequency is excluded, that is, filtered over the entire audio frequency to secure the clearness of the audible tone AF to the utmost. Furthermore, a distortion component included in the audible tone that cannot measure by an audible frequency measurement device is also eliminated and a balanced tone with high clearness is obtained without a complicated operation required for a negative feedback amplifier.;COPYRIGHT: (C)1997,JPO