Echo suppressor with switches for telephone systems - has amplifier delivering constant output signal and controlling threshold detector

摘要

The suppressor has a receiver responding to a control tone. The receiver has at its input a preamplifier stage followed by a wideband control amplifier without limiter effect. It delivers a constant output signal and controls a selective threshold detector with automatic band width switching. Its response threshold is only a little below the level of the constant output signal. The threshold value detector is connected through a double branch line unit (V4, V5) and uses an inverter unit (TS4) to control the echo trigger transistor. The method enables an enhancement to be obtained of the signal strength from marine cables and satellite communication signals.