Rybka S. "The method of cancellation of interference with variable parameter in multichannel modems

There is on the defense the method of design of the digital filter systems for tele-communication modems with enhanced interference tolerance. The state and prospects of development of equipment of telecommunication net-works, including modern modems is analyzed. Research of common properties of construction of modems, descriptions of hin-drances, which it is necessary to take into account at the choice of parameters and structure of modem, is conducted. The comparative analysis of efficiency of the reconstructed digi-tal filter systems is conducted. The methods of digital filtration of hindrances of type of electric echo are offered and digital adaptive equalizing in multi-channel modems for tele-communication networks. The method of approximation of combs of bandpass digital filters is developed. The original method of receipt of transmission function of digital filter with the use of ideal analog prototype which satisfies the maximum condition of linear of phase response, is of-fered. In subsequent, using the direct method of synthesis, it is suggested to conduct the decision of task of approximation in two stages, on the first, for the receipt of the initial approaching, to apply the method of interpolation, on the second is optimization. It is shown that the task of global nonlinear optimization of frequency descriptions of digital filter can be taken to the sequence of linear tasks of optimization. The algorithm of succes-sive decision of tasks of interpolation of approximating function and optimization of fre-quency descriptions of digital filter is developed with the set assured fading in the bar of detention and possible unevenness in the bar of admission, which takes into account li mi-tations of bit scale of element base. Principles of construction are grounded; descriptions of sensitiveness to the errors of task of coefficients of digital filters with a frequency selection are explored. The statistical analysis of influencing of external noises and noises, quantization errors of coefficients of digital filters and rounding off results of arithmetic operations internal and is conducted. Descriptions of correct discovery of signals on background hindrances at the use of the digital filter systems are expected. Comparative estimates of apparatus charges at construction of band pass digital filters on the base of processors of the fast Fourier transform and digital filters with a frequency sample are given. The necessary volume of memory and number of the specialized processors for apparatus realization of the digital system of treatment of signals in real time is appraised.