Circuit for the suppression of the Larsen effect in the false call zone for a subscriber telephone set.

摘要

1. A circuit for suppression of the Larsen effect in the false call zone "B" for a subscriber's telephone set of the kind comprising in particular a line interface (5), a receiver for listening (3) and a microphone (2) connected to this interface by appropriate amplifiers (7, 9), and an anti local (6) which receives a line signal (15) and an amplified signal (12) for the receiver, characterized in that it also comprises upstream from the anti local a comparator (11) which emits a signal for activating an element (10) for isolating the microphone (2) when a signal (14) proportional to the line current becomes smaller than a signal (13) representing a threshold current, in order to avoid a Larsen effect.