Circuit arrangement for recognizing zero transitions of signals

摘要

A circuit arrangement for recognizing zero transitions of signals includes a zero transition detector which receives the signals and an amplitude evaluator. The zero transition detector produces rectangular pulses which are assigned to the zero transition of the signals and the amplitude evaluator produces amplitude signals which, at least until the occurrence of the next zero transition, indicate that the amplitude of the signals was, prior to this particular zero transition, greater than the amount of a given threshold voltage. A switching stage is provided which is supplied with the rectangular signals and with the amplitude signals and which emits further signals at its output when the rectangular signals and the amplitude signals are present. A time filter is provided which is supplied with the further signals output by the switching stage, the time filter emitting pulses assigned to the further signals only when the interval of time between two changes in the further signals overshoots a given duration of time.