Sallen-Key Family Passband Filter with Independent Control of the Basic Parameters

A new passband filter (PBF) circuit of the Sallen-Key family is considered, in which independent control of the basic parameters (pole frequency, quality factor and transmission coefficient) by digital potentiometers is implemented. The basic mathematical expressions for the transfer function of active RC filters and the parameters of its frequency response are obtained. The results of PBF modeling in the Micro-Cap are discussed, which confirm these properties of active RC filter. The proposed Sallen-Key PBF circuitry is recommended for filtering signals in automation, radio engineering and communication devices. Due to the appropriate choice of parameters of active and passive elements, it is possible to ensure the operation of the Sallen-Key PBF under consideration both at low and high frequencies.