Sinusoidal and square wave voltage controlled oscillators

This paper presents a sinusoidal Wien-bridge and square wave wide range voltage controlled oscillators. The square wave oscillator's uses ring and relaxation (Schmitt trigger) topology. All described oscillators have potential using in different application, 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.