E.I. Algazin, A.P. Kovalevski, V.B. Malinkin

The method of estimation of the noise immunity of the invariant system based on the synchronous detector is offered. Such method is based on using a special code of transmitted signals and their further processing on receiving side. The coding of the signals of transmission consists in forming of consecutively transmitted blocks, each comprising of informative and training parts. Demodulation of the received signals consist in calculation of the ratio of the energy of the signals of the informative part to the energy of the signals of the training part. The channel of connection with the multiplicative noise minimally influences the ratio. Analogous expressions on calculation of density of the probability of the invariant estimation are listed in the paper. The calculation of the probability of the parwise transmission of one invariant into another is made on their basis. The quantitative indices of the propose system are calculated by different conditions such us: the quantity of accumulation with the averaging of the training signal, the coefficient of the channel transmission on the interval of stationarity. The curves of the noise immunity proving the effectiveness of the given method are calculated. The curves of the noise immunity are calculated on the basis of machine modulation.