I.M. Jasinskiy - Ph.D. (Eng.), leading researcher, JSC «Omsk research institute of instrument engineering». E-mail: info@oniip.ru
A.I. Tyumentsev - Design Engineer, JSC «Omsk research institute of instrument engineering». E-mail: freemaster@inbox.ru

Frequency-selective LC-filters of various types find a wide application in engineering radio communication. Except requirements to their amplitude- and phase-frequency characteristics in the last time it is required to provide factor of a standing wave (FSV), which doesn't exceed a certain value in the set frequency band. For FSV improvement the additional four-terminal network, which are connected sequentially or in parallel entrance clips of filters or in parallel by input terminal of filters or in parallel on input RL, RC filter or RLC two-terminal networks, are entered. These methods of input resistance alignment are labour-consuming enough at the choice of the most comprehensible values of correcting additional circuits elements, are developed insufficiently for the applied problems decision, and their application in tunable circuits is almost inapplicable. The article offers the filters various type realization model with constant input resistance. This model is executed in the form of two phase contours, connections on input in parallel, and the algebraic adder. The factor of such structure standing wave can be obtained closer to one, as in pass band, and in attenuation band.