Abstract: In a radio telephone system with mobile and stationary transmitting receiving stations and, connected to the stationary stations, a common switching station through which the mobile stations can be interconnected and connected to the subscribers of a line-wire telephone network, a faster connection set-up and a likewise faster switch-over of existing connections is possible because the stationary stations repeatedly transmit through their cell channel a channel number of a free duplex speech channel which is stored in a storage device in the mobile stations receiving the call channel. In response to a connection set-up command the stored channel number is used for automatically selecting the free duplex speech channel.

Abstract: FM-radio receiver having an audio amplifier stage, provided with switching means, and a squelch circuit which is coupled to the output of the receiver demodulator, this squelch circuit comprising two circuits which are constructed in such a manner that one circuit produces at an early stage an output signal when co-channel interference occurs whereas the other circuit produces an output signal which controls said switching means and which occurs only at an impermissible signal/noise ratio and/or an impermissible degree of co-channel interference.

Abstract: Multichannel generator for at will generating any one of a plurality of channel frequencies in the GHz band which are spaced from one another by equal channel distances. The multichannel generator is constituted by a frequency synthesis device which comprises two phase-locked loops which each comprise an oscillator, a divider adjustable in discrete steps and a phase detector to which a reference frequency is applied. The adjustable dividers keep in step. One of the oscillators is coupled via a fixed divider and a mixer stage to the adjustable frequency divider included in the relevant loop. The signal injected into the mixer stage is derived from the other oscillator. The influence of the fixed divider on the value of the channel spacing is avoided by a particular relationship between the reference frequencies supplied to the phase detectors.