A sinusoidal tuned VCO using linear OTA's

선형 OTA를 이용한 사인파 동조형 전압-제어 발전기

A sinusoidal tuned VCO based on linear OTA's has been designed for instrumentation and measurement applications. It consists of a noniverting amplifier, a hard limiter, and a current controlable LC-tuned circuit which is realized vy two linear OTA's and two grounded capacitors. A prototype circuit has been built with discrete components. The experimental results show that the proposed VCO has a linearity error of less than 6.5 percent and a temperature coefficient of less than 200ppm/$^{\circ}C$ over a bias current range form 5$\mu$A to 100 $\mu$A(or an oscillation frequency range form 775.5 Hz to 20.371 kHz). A total harmonic distortion of 0.6 percent was measured for a peak-to-peak amplitude of 5V.