Device for avoiding sustained disturbing oscillations in a closed-loop system and loud-speaking telephone apparatus utilising this device

Abstract

Abstract 1. An arrangement for avoiding sustained, annoying oscillations in a closed-loop system, and comprising a variable-gain amplifier (11) incorporated in a first path (C1) which forms part of the loop of the said system, characterized in that between the input (A) and output (B) terminals of the first path there is formed a second path (C2) which has at least one part which is separate from the first path, means being provided to ensure that the gain in the second path remains higher than the gain in the first path in the overall frequency band where the oscillations are liable to be produced, a signal formed in the said part of the second path which is separate from the first path being applied to the input of a linear regulator (13) controlling at least one variable-gain amplifier (12) which forms part of the second path (C2) to ensure that the signal at the input of the said regulator remains constant from a given value of the said signal formed in the second path.

Inventors

• 👤 Gilbert Marie Marcel Ferrieu
• 👤 Yves Jean François Hetet
• 👤 Jacques Yves Balch

Bibliographic Details