FIELD: radio engineering, as one of devices used to enhance noise immunity of nation-wide communication services at moment of retuning of discretely tuned attenuator under conditions of high-power out-of-band interference. SUBSTANCE: facility includes discretely tuned attenuator, clock pulse generator, reversible counter and decoder connected in series, output of the latter being connected to control input of attenuator, connected in series detector which input is connected to output of path of preliminary selectivity of radio receiver and threshold unit controlling clearance to count and condition of reversible counter. Signals of threshold unit and clock pulse generator form with the aid of AND gate signal to activate generator of pulses which control key disconnects narrow-band path of radio receiver in case of commutation interference. Duration of commutation interference depends on value of Q-factor of path of preliminary selectivity which it assumes in process of frequency tuning. Technical result lies in ensured serviceability of facility with various values of Q-factor of path of preliminary selectivity which is achieved by insertion of facility with generator of pulses with controlled duration which adjustment input is connected to unit of retuning of path of preliminary selectivity. EFFECT: ensured serviceability of facility with various values of Q-factor. 1 dwg
