The Method of Adjusting the Amplitude–Frequency Characteristics of Filters

Abstract

Background. The relevance of the topic of this work is due to the need to reduce the level of penetrating interference and improve the quality of the useful signal received by the on-board active interference station. Goal. Improving the quality and functional parameters of on-board frequency-selective systems and structures by adjusting the amplitude–frequency characteristics (AFCs) of filters. Methods. The system analysis of the main parameters, modeling of the frequency characteristics of attenuation and the standing wave voltage coefficient, expert assessments, and research tests have been used. Materials. To improve the characteristics of the filters, it is proposed to adjust (control) the AFCs of the filters. The schemes and topologies of correctors are given. It is shown that with the help of thin-film and thick-film correctors, various frequency response distortions can be eliminated, the slope of the characteristic can be adjusted, and the depth of the AFC dip can be changed. Results. The proposed schemes, designs, and topologies of correctors make it possible to adjust the slope of the characteristics up to 16 dB, change the depth of their dip, maintain the voltage standing wave ratio within 1.35–2.5 in the operating frequency range, reduce the frequency response nonuniformity to 0.2 dB, and the noise factor to 2.3–2.4 dB. To ensure such a level of performance during the adjustment process, it is required to carry out an individual combined adjustment of the resistors in the range from –10% to +30% or functional adjustment according to a template. At the same time, the flare discharge method provides a higher time stability of the frequency response adjustment indicators and a higher yield of suitable products as compared to the laser method. Conclusions. The proposed method of adjusting the AFCs of the filters in a frequency-selective system makes it possible to improve the quality of the useful signal received by the active interference station. Adjusting the frequency response by adjusting the resistances of the corrector resistors by the flare discharge method provides a higher temporal stability of the parameters than the laser adjustment.