A realization of biquadratic circuit transfer functions using OTA-C integrator loop structure

This paper introduces a way to realize biquadratic circuit transfer functions using operational transconductance amplifiers (OTAs) and grounded capacitors. The basic circuit configuration is constructed with five OTAs and two grounded capacitors. It is shown that the circuit can realize low-pass, band-pass, high-pass, band-stop and all-pass transfer functions by suitably choosing input terminals, and that the circuit parameters can also be set orthogonally by tuning the bias currents of the OTAs with the proportional block. Although the circuit configuration has been known, it seems that the feature for realizing their transfer functions makes the structure more attractive and useful. An example is given together with simulated results by PSPICE.