Differential Difference Amplifiers in the Second Order Low-Sensitive All-Pass Active RC-Filters

We have developed the second order all-pass active RC-filter`s (ARCF) architecture based on two differential difference amplifiers. The suggested low-sensitive ARCF provides an amplitude-frequency responses' (AFR) complete set (low pass filter LPF, high pass filter HPF, band pass filter BPF, rejection filter RF) for signal frequency selection's typical tasks in instrument engineering, communication, automatics. The said ARCF is differentiated by the following: its transfer ratio and pole frequency are not changed, when the pole Q-factor is adjusted. Here a concrete type filter's implementation is provided by using ARCF's different inputs and different outputs. We have given analytical expressions, which allow ARCF's parametric synthesis. We have discussed the computer simulation results for amplitude-frequency responses of LPF, HPF, BPF and RF. We recommend applying ARCF in specialized structured arrays, which are advanced in frequency selection devices' small volume production conditions and special operation condition requirements (neutron flux, low temperatures etc.).