Multi-Functional Programmable Active RC-Filters with Digital Elements for Parameter Resetting

Two promising modifications of the multi-functional programmable active filters (PAF) are developed and investigated. The proposed PAF circuits of second order are implemented on the operational amplifiers and have an increased stability of the Q-factor. The basic equations and the results of computer simulation are presented, showing that the developed circuits implement band-pass filters (BPF), low-pass filters (LPF) and high-pass filters (HPF). New modifications of the PAFs allow resetting of the pole frequency using resistor arrays R-2R or digital potentiometer microcircuits. A comparison of the main characteristics of the proposed PAF and the PAF based on famous KHN filters is given.