Electronically Tunable First Order All-Pass Filter using Synthetic Inductor


Mousiki Kar

Author affiliation

Department of Electronics and Communication Engineering, Heritage Institute of Technology, Kolkata-700107, India


An electronically tunable first order all-pass filter structure using a Multiplication Mode Current Conveyor (MMCC) building block is presented. The control voltage (V) of the MMCC tunes the desired phase (θ) while the time constant can be adjusted by the CFA-based synthetic lossless grounded inductor (L). When the circuit is analyzed taking into account the device non-idealities, low active sensitivity of the design is observed. The effects of port transfer error (ε) have also been studied. The circuit is implemented using readily available AD-844 type Current Feedback Amplifier (CFA) elements. The circuit has been successfully tested for electronic θ-tunability, upto about 250 KHz by PSPICE simulation and with hardware experimentation.


MMCC; All pass filter; Synthetic inductor; CFA