Estimation of the Influence of Additive and Multiplicative Noise with Low Level on the Accuracy of Measurement of Signal Information Parameter

The analysis of the influence of fluctuation stationary multiplicative (modulating) noise acting simultaneously with additive noise on the measurement accuracy of non-energy parameters of information signals is carried out. The term “low” level of noise with the combined effects of multiplicative and additive noise is clarified. It is shown that mathematical characteristics, bias, measurement errors and error dispersion can be used as characteristics of the accuracy of measuring signal parameters at a low level of noise. The structure of the optimal receiving device for measuring one information parameter with a random initial phase against the background of additive noise is obtained. An expression is obtained for the envelope of the signal at the output of the linear part of the optimal meter according to the desired information parameter. It is shown that at a low level of multiplicative and additive noise, the estimate of one parameter of the useful signal is unbiased, and its dispersion is the sum of two terms, the first takes into account the influence of additive noise, the second is multiplicative noise. Expressions are obtained for the variance of the estimation of the information parameter under the simultaneous effect of additive and multiplicative noise. The above expressions show that the variance of errors due to the presence of multiplicative noise significantly depends on the spectral characteristics of the noise modulation function. It is noted that slow multiplicative noise is the most dangerous.