Linearly tunable Wien bridge oscillator realised with operational transconductance amplifiers

Starting from the classic Wien bridge oscillator (WBO), a new operational transconductance amplifier (OTA)-based sinusoidal oscillator configuration is evolved which provides linear control of oscillation frequency through an external current signal: a major advantage over op-amp-based WBOs. In contrast to a recent oscillator by Abuelma´atti and Humood which employs five OTAs, the present circuit employs only three OTAs (along with two capacitors and one resistor), yet still provides the essential properties available in Abuelma´atti and Humood´s proposition.