HOWLING-PROOF CIRCUIT FOR EAR SET

摘要

PURPOSE:To prevent howling from being generated by connecting an ear set type transmitter/receiver to the various kinds of telephone sets or radio communication equipments with high acoustic coupling and to also prevent howling from being generated corresponding to the using state of the ear set type transmitter/receiver. CONSTITUTION:Concerning the ear set type transmitter/receiver, a transmitter 2 and a receiver 3 are integrated and mounted on the ear so as to enable two- way simultaneous speaking. This circuit is provided with a reception rectifier circuit 5 for converting an AC voice signal inputted to the receiver 3 to a DC signal, level setter 6 for transmitting an output when an output from this reception rectifier circuit exceeds a fixed level decided in advance, and gain switcher 4 to lower a voice output from the transmitter just for a suitable amount corresponding to the output from this level decider.