Acoustic feedback susceptible electroacoustic system regulation - setting selected amplifier stage with feedback control off whenever system is put into operation.

摘要

The method involves reducing whistles due to acoustic coupling between a loudspeaker (LSP) and microphone (MIF) by a squelch circuit (SQE) operating on a transmission amplifier (SV) and loudspeaker amplifier (LHV) sharing the output of a reception amplifier (EV) with an earphone (HK). The 'on' and 'off' states of the feedback control are associated with individually adjustable amplification stages, esp. by a microprocessor programmed so that, at each operation, the stage is automatically adjusted for which at the max. gain no feedback control is necessary. ADVANTAGE - "Pump noise" arising from squelch control in telephone terminal equipment is overcome.