this invention relates to signal transmitting engineering . the use of the inventive method demodulation of a signal of multiple position frequency manipulation with equidistant frequency spreading allows to reduce the threshold of demodulation and to ensure a quality of demodulation , which is at least identical to that of a quasi - optimal demodulator . to obtain such a result , a frequency grid is formed with a possibility of precise tuning of frequency spreading ; during the reception , values having a maximum module of reception signal are extracted at all frequencies switchable values at clock frequency , this clock frequency is extracted from maximum of the received signals and is used for a precise tuning of the frequency spreading ; a grid of tunable frequency is tuned with a precisely tuned frequency spreading for exact values of a frequency of received signal , and demodulation is effected by the way of coherent reception of the received signal , using only one from quadrature signals to decide whether a signal of a determined frequency is absent or present among the mentioned exact values of frequency .