A method for switching between a as well as transversely thereto or vormodulations - and a vorgruppenmodulationssystem

摘要

When changing from a first carrier frequency system to a second carrier frequency system of a different type, the switching through of single voice channels or groups of channels (10, 11, 12) presents a problem. In the invention, the basic group of the first carrier frequency system (GP1) is obtained in accordance with the premodulation principle whereas it is obtained in accordance with the pregroup modulation principle in the second carrier frequency system (GP2). The basic group of the first carrier frequency system (GP1) is converted with one of its channel carriers (KT1) in such a manner that the voice channel or the group of channels (10, 11, 12) to be switched through is placed at the frequency of a circuit switching filter (D). The frequency band filtered out by means of the circuit-switching filter (D) is directly converted into the desired frequency of the basic group of the pregroup system (GP2) by means of a carrier of the premodulation system (KT2). IMAGE