Automatically controlled amplifier arrangement.

摘要

An automatically controlled amplifier arrange­ment comprises a controlled amplifier unit (35), a detection unit (2) for detecting oscillations of the arrangement in the case of acoustic feedback during operation, and a control unit (3) which in response to the detection unit (2) controls the gain of the amplifier unit (35). The controlled amplifier unit comprises separate control means for separately controlling the gain for different frequency bands (1′, 1′′, 1′′′) below the howling limit. Prior to this an pre-adjustment is effected. Further, a circuit is proposed which increases the gain during preadjustment until oscillation occurs and which sub­sequently reduces the gain (if desired for each frequency band) until an adjustable margin below the howling limit is obtained (if desired for each frequency band).