СЕМЕЙСТВО АКТИВНЫХ RC-ФИЛЬТРОВ ВТОРОГО ПОРЯДКА (ФНЧ, ФВЧ, ПФ) С НЕЗАВИСИМОЙ ПОДСТРОЙКОЙ ОСНОВНЫХ ПАРАМЕТРОВ

Abstract

A bank of circuit design solutions for active RC filters of the second order is considered - alow-pass filter, a high-pass filter and band-pass filters, in which independent tuning of the mainparameters - the pole frequency, the quality factor of the pole and the transmission coefficient isprovided. From these positions, the requirements for three special transfer functions of a multipolefrequency-setting RC circuit, which contains two resistors and two capacitors, are formulated.By choosing the coefficients of the numerator of the first transfer function, the type of the requiredfilter (LPF, HPF, BPF) is implemented. The coefficients of the second transfer function are chosenso that they affect only the frequency of the pole. It should be noted that, depending on the set ofcoefficients of the transfer function numerator polynomial, the developed circuits have the propertyof lowering the pole frequency or increasing the pole frequency. In this case, the choice of parametersof the third transfer function provides the necessary attenuation of the pole. Using theThe introduction describes a generalized architecture of second-order active RC filters, whichallows implementing an algorithm for step-by-step tuning of the main parameters and can be usedas the basis for the synthesis of many other modifications of active RC filters. For correct independentadjustment, the following sequence must be observed: the frequency of the pole, the secondstage is the adjustment of the quality factor of the pole, and the third stage is the scalingfactor. The stages of synthesis of this class of active RC filters are considered, the coefficients ofthe transfer functions of the presented circuits of 12 band-pass filters, a high-pass filter and a lowpassfilter, confirmed by 14 patents of the Russian Federation, are given.