Abstract: A device comprising a demodulator, equipped with a frequency synthesizer for synthesizing different tuning frequencies, for use in radio receivers. The device further comprises a counter for counting the number of "clicks" at the demodulator output, for each tuning frequency. A microprocessor is provided for identifying the tuning frequency for which there is a minimum of "clicks," this being the correct tuning frequency. The microprocessor acts on the synthesizer for tuning the frequency of the synthesizer at the correct tuning frequency.

Abstract: A channel board which simplifies wiring.Each channel board 30-31 comprises its own controlled carrier current generator for the formation of primary groups, and preferably also for the direct formation of the secondary groups from pre-modulated channels. The requisite carrier current is obtained by controlling the value of the divisor N in the frequency divider contained in the feedback loop. The control of N is effected for example simply by inserting the channel board into its location or by providing in addition with a selector plug, or by means of loaded shift registers.