Apparatus for transmission and reception of frequency modulated digital communication signals

摘要

A system for the reception of digital communication signals which are modulated onto a carrier in the form of binary frequency modulation and in which the information losses occurring due to phase and amplitude distortions caused by multi-path propagation are automatically detected in two separate arrangements, one being a frequency discriminator and an amplitude demodulator. The outputs of the two demodulators are connected to a data analyst circuit DA which includes a switching means (13), a regenerator (15) which is connected to the switching arrangement and an AM decision unit (14) which analyzes and determines the switch-over criteria. Mounted before the change-over switch (U) is the switching arrangement (13) which includes a blockable phase follow-up device (PE) for compensating large phase differences between the AM and FM demodulation products which are to be analyzed. The AM decision device includes a time evaluation circuit (ZB) for deriving the switching signal for the change-over switch and for obtaining the control signal for the blockable phase follow-up device (PH).