A New Electronically Tunable Transimpedance-Mode OTA-Based First-Order Universal Filter and its Quadrature Oscillator Application

This paper suggests a new operational transconductance amplifier (OTA) based electronically tunable transimpedance-mode first-order universal filter (FOUF). The suggested FOUF produces all-pass (AP), high-pass (HP) and low-pass (LP) filter responses simultaneously. It employs three OTAs, two grounded resistors and only one grounded capacitor. Owing to use of grounded passive elements, the suggested FOUF is suitable for integrated circuit implementation. It operates at low power supply voltages. Additionally, the resonance frequency of the suggested AP filter can be adjusted in a wide frequency range. However, the suggested FOUF consists of only one matching condition. Moreover, a sinusoidal quadrature oscillator (QO) application that is derived from the suggested FOUF topology is given. The suggested FOUF and its QO application are simulated by using 0.18-mu m TSMC technology parameters in the SPICE program to validate the presented theory. Finally, an experimental test is performed to demonstrate workability of the suggested AP filter.