The radio frequency module (2) comprises a PLL oscillator and a microprocessor (8) to recognise a definite value of a frequency set on the rotating switch (9) by user of transmitting device and on the basis of the frequency data in ROM (8-1) These data are passed to a PLL circuit (3) in the module for setting a frequency divider, dividing the frequencies from the voltage-controlled oscillator (5). The frequency produced is sent to a frequency comparator and compared with a reference frequency, passing then to low-pass filters (7) and used as an error-voltage signal for the oscillator.
