FIELD: radio engineering and communication.
SUBSTANCE: invention relates to radio engineering and can be used in communication systems. Prior to setting values of frequency shifts between adjacent signals so that value of difference of any pair of frequencies does not exceed value of frequency, for which the difference between the amplitude-frequency characteristic (AFC) of the low-pass filter (LPF) and the band-pass filter becomes less than a certain predetermined value; after multiplication by corresponding reference signals in multipliers, results of signal and interference conversion are formed, each of which is branched into two identical components: a first component, LPF is filtered, whose band is matched with a signal band; simultaneously second component is filtered by band-pass filter, which pass band is selected so that upper frequency of band-pass filter corresponds to upper frequency of signal, lower frequency of band-pass filter is set as close as possible to zero value, signals passed LPF and band-pass filter are subtracted from each other in each line, obtained signals are converted to digital form in corresponding ADC; obtained values are summed up and stored; sum with the maximum value is found from the obtained sums; determining the threshold value by multiplying the found maximum value by a coefficient, value of which is set in advance; obtained sum values are compared with a threshold; based on the comparison results, the presence or absence of a signal with the corresponding frequency is stated.
EFFECT: technical result consists in improvement of noise immunity of communication equipment.
1 cl, 2 dwg
