Frequency Responses Resistance to Variations of Electric Filter Parameters

When electric filter designs "on the whole" circuit's parameters are determined as a result of solving the system of equa-tions formed by equating of coefficients at equal powers of the variable in terms of desirable transfer function (TF) and TF filter. The solution of the system of nonlinear equations is the set (or sets) of filter parameters. The transition to practical realization requires bringing the filter parameters to the standard range of nominal values. The frequency responses of the filter are distorted, when the calculated values are replace on the nominal values. Moreover, the nominal value scales themselves have different range of values depending on the selected range. The purpose of the article is to develop evalu-ation methods of amplitude- and phase-frequency responses resistance of low–pass and high–pass filters to parameter variations during the filters realization. The integral square function of a variable is taken as a measure of deviation of the real frequency response from cal-culated characteristic. The specific parameter response resistance is defined as the inverse average value of the integral function at the giv-en range of the parameter variations. The inverse sum of average values of the integral function for the specific set of el-ements serves as integrated evaluation of response resistance to the filters parameter variations. In case there are sever-al solutions of the system of equations, providing filter synthesis, the one should be used that gives closest to the maxi-mum value of integrated evaluation of resistance. The introduced definitions allow to fulfill the successive selection of fil-ter elements in the light of the impact of each element in the total evaluation of the frequency response stability.

Authors: E. N. Chervinskiy

Direction: Радиотехнические средства передачи, приема и обработки сигналов

Keywords: Transfer function, synthesis of the filter "on the whole", inverse low-pass filter, quasi-elliptic low-pass filter, high-pass filter, response resistance by parameter, complex valuation of resistance

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