All-Pass Second-Order Active RC-Filter with Pole Q-Factor's Independent Adjustment on Differential Difference Amplifiers

The article presents a scheme of active RC-filter of the second order (ARCF), which is realized on multidifferential operational amplifiers (DDA). Based on this filter, we can obtain a various amplitude-frequency characteristic (AFC) (low-pass filters (LPF) and high-pass (HPF) filters, band-pass (BPF) and rejection (RF)filters). The main difference between the developed ARCF and the known ones is that when adjusting the quality factor of the pole, their pole frequency and transmission coefficient do not change.