Sinusoidal and Relaxation Wide Range Voltage Controlled Oscillators

Abstract

This paper presents a sinusoidal Wien-bridge and square wave wide range voltage controlled oscillators. The square wave oscillator is based on relaxation (Schmitt trigger) topology. All described oscillators have potential use in different applications, e.g. phase locked loops, modulation and detection. The frequency changing is based on optically coupled resistor with 100 dB dynamic range. The oscillators were constructed and measured. The new method for amplitude control for quadrature oscillator is also described.

Keywords

• wien-bridge oscillator
• relaxation oscillator
• phase locked loop
• voltage controlled oscillator
• photoresistor
• quadrature oscillator