M.Yu. Aliev - Head of Department, JSC «Typhoon» (Kaluga). E-mail: arls@mail.ru A.V. Maksimov - Ph. D. (Eng.), Associate Professor, Department «Compute systems and networks», Kaluga branch of the Bauman MSTU. E-mail: av_maximov@bk.ru N.V. Tatyanich - Ph. D. (Eng.), Associate Professor, Department «Compute systems and networks», Kaluga branch of the Bauman MSTU.

When designing digital filters to the developers it is very difficult to provide a straight front amplitude-frequency characteristics. The need to limit the number of links of the digital filter, and the resulting time constraint of action impulse response filters, will inevitably lead to blockage of the fronts and the emergence of emissions and pulsations in the frequency characteristic of the filter, leading to distortion of the processed signals. The real digital filters amplitude-frequency characteristics substantial differ from the ideal. The fronts of the real filters have the Insta-vulnerable blockages and bandwidth and have the retention of emissions and pulsations, causing linear distortion to the signal. The practice of designing digital filters has shown that the requirement of Squareness fronts their amplitude-frequency characteristics leads to significant complication of the hardware of the filters. And this, in turn, stimulates the parasitic excitation in the apparatus. One solution to this problem can be the development of methods of synthesis of digital filters based on the specified parameters of the transition zone. The development of such techniques is possible if the dependence between the width of the transition zone cha-racteristics of the digital filter and the number of samples of the digital filter. In this paper, the method of assessing the number of required samples transversal digital low-pass filter in the amplitude-frequency characteristic with a predetermined transition area. The work was carried out in the following sequence. Geometrical model of the re-quired characteristics of the designed filter, convenient to use Fourier transform. Built auxiliary impulse response of the filter of the future and then she discretizethe team is being built. Auxiliary impulse response is shifted in the time domain is built and the frequency response of the digital filter based on a specific number of samples. The results are summarized in graphs. This method allows for the same specifying the width of the transition zone to reduce the number of samples of impulse characteristic in comparison with known design methods. Research carried out by the method of mathematical modeling on a universal PC. Graphs of the influence of the number of counts of the filter on the real width of the transition zone the amplitude-frequency characteristics. In the work of nine figures, the bibliography includes eleven works.

 

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