A Method of Analytical Calculation of Dynamic Characteristics of Digital Adaptive Filters with Parallel-Sequential Weight Summation

Abstract

AbstractIn this article, we present the result of the research concerning the development of a method for analytical calculation of the dynamic characteristics of digital adaptive filters with parallel-serial weight summation of signals for one of the variants of a multi-stage adaptive interference compensator with block orthogonalization of compensation channel signals. The article also presents the results of a research of the degree of coincidence of the results of theoretical calculation and statistical modeling of the adaptive compensator (filter) for interference suppression. Each stage of the adaptive filter with parallel-sequential weight summation consists of modules, which are a scheme of a single-channel adaptive compensator. The complex envelope of the signal from the output of the digital antenna array (DAA) is goes to the main channel of the adaptive filter. Compensation channels are formed on the basis of the antenna elements of the main channel. Equidistant antenna array with a distance between the array elements equal to 0.5 wavelength is selected as the DAA. The method consists in obtaining recurrent relations, according to which the transmission coefficients of the modules placed in the first stage (row) of the structural scheme of the adaptive filter with parallel-sequential weight summation of signals are first calculated. Then, the transmission coefficients of the modules placed in the second stage (row) of the structural scheme are calculated, etc. The calculated values of the transmission coefficients of all modules of the structural scheme of the adaptive filter with parallel-sequential weight summation are used to calculate the interference power at the output of the filter, depending on the parameters of the interference correlation matrix. Also, statistical simulation modeling and theoretical calculation of dynamic characteristics of an adaptive filter with parallel-sequential weight summation of signals was performed. The results of modeling and analytical calculation of interference power at the output of the adaptive filter with parallel-sequential weight summation show a satisfactory coincidence of dynamic characteristics under the action of two, three and four sources of interference on a 5-channel adaptive filter. The modeling can be reproduced many times for different interference situations. The drawback of this method is that it is developed for a single variant of the known scheme of a multistage adaptive noise compensator with block orthogonalization of signals. The use of the method will allow at the design stage of the structure and characteristics of adaptive filters with parallel-sequential weight summation to choose its parameters without the use of statistical modeling. KeywordsRadio-electronic meansDigital antenna arraySpatial signal compensationDigital adaptive filter with parallel-sequential weight summation