Abstract
Analog signal processing is very important technology for many reasons. Voltage followers are suitable active elements for a realization of high-frequency active RC circuits. A synthesis of chain active RC filters is proposed by which the lowpass function can be realized with voltage followers.
This paper describes compensation method of the cutoff frequency shift for the active RC filter due to the low absolute accuracy of passive elements on a monolithic chip. The proposed filter is connected to a voltage controlled variable resistance, which determines resistance with a DC voltage Vc externally connected.
As an example, a fifth-order Butterworth chain active RC filter is designed for frequency of 100kHz. SPICE simulation results are shown to demonstrate the effectiveness of the proposed method.
