Sinusoidal Oscillators

Abstract

Communication transceivers require oscillators that generate pure electrical sinusoidal signals (“tones”) for further use in modulators, mixers, and other circuits. Although oscillators may be designed to deliver other waveforms as well, e.g. square, triangle, and sawtooth waveforms, if intended for applications in wireless radio communications, the sinusoidal waveform is probably the most important one. A good sinusoidal oscillator is expected to deliver either a voltage or a current signal that is stable both in amplitude and frequency. Because a variety of oscillator structures are available that are suitable for generation of sinusoidal waveforms, circuit designers make the choice mostly based on their personal preference for one particular type of oscillator. In this chapter, we study several oscillator circuits, with emphasis on understanding the underlying principles, rather than very detailed analysis of any special oscillator type.