A CMOS quadrature oscillator with deterministic output sequence

Quadrature oscillators usually suffer from output signal phase ambiguity. A modified quadrature oscillator is proposed, where the output sequence is deterministic. Simulation and measurements show that the modified QOSC has little degradation in phase noise or increase in power consumption, and has a unique output sequence. The circuit dissipates 6 mW and tunes from 1.37 to 1.85 GHz.