Generation of Sinusoidal Voltage (Current)-Controlled Oscillators for Integrated Circuits

Sinusoidal oscillators with large tuning range and small harmonic distortion offer various applications in integrated electronics. In this paper a method of generating sinusoidal voltage-controlled oscillators (VCO) and/or current-controlled oscillators suitable for integrated circuits is presented. Each oscillator circuit contains two fixed resistances, two fixed capacitances, and amplifiers. It is shown that one amplifier can be used to confine the natural frequencies of the circuit on the axis of the complex frequency plane, and the other amplifier (or amplifiers) can be used to effectively increase or decrease the time constant and hence change the oscillation frequencies.