schaltungsanordnung for a digital transmission techniques in telecommunications, in particular fernsprechvermittlungsanlagen used phasenregelschleife

摘要

In the circuit arrangement according to the invention, a bit and noise detection device is provided which responds to frequency changes in the input signal caused by interference and/or data transmission and which controls a changeover device. The transmission clock originating in the oscillator of the phase-locked loop is thus offered to the phase-locked loop instead of the receive transmission clock as a phase comparison signal. The bit and noise detector is de-activated once more after a predefined time so that the changeover device again though-connects the receive transmission clock to the phase-locked loop.