A First-order All-pass Filter Based on LT1228 and Its Application

This paper proposes a first-order all-pass filter (APF) that employs two LT1228s, a resistor, and a grounded capacitor to be implemented via commercially available integrated circuits. The phase response of the proposed filter is electronically controllable by modifying the transconductance value via the biasing current of the OTA (IB1). The oscillator quadrature sinusoidal signal circuit is generated by the proposed APF, which includes an integrator. The efficacy of the sinusoidal oscillator circuit and the proposed APF is validated through the use of experimental results and simulations. The results that were obtained are in strong agreement with the theoretical predictions.