FIELD: radio engineering, technical cybernetics. SUBSTANCE: invention can be used to detect weak signals and to evaluate noises. Proposed process lies in time discretization of input action, in discretization of amplitudes of received signals, in formation of sequence N of signal selects, in formation of threshold level A proportional to dispersion of noise, in comparison of signals with threshold level A. Selects Bk of signals within limits of observation interval are formed as number of signals with identical amplitudes k, k = 1...N. At end of observation interval with formation of threshold level dispersion of noise σ2 is determined as 
with 
. Device for realization of process has signal time sampler and level quantizer, adder, first and second squarers, first and second subtracters, threshold element, unit forming threshold level, former of select number, second adder, first and second commutators, first division circuit, first multiplier, third adder, second multiplier, fourth adder, third multiplier and second division circuit. EFFECT: enhanced probability of detection of signal. 2 cl, 1 dwg
