Voltage controlled oscillator with dual loop resonant tank circuit

摘要

A voltage controlled oscillator (VCO) has an LC tank circuit which is pumped by two out-of-phase feedback components. The combined effect of the two out-of-phase feedback components results in an effective feedback signal that is a function of the ratio of the magnitude of the two out-of-phase coponents. The magnitude of one of these feedback components is controlled by a CMOS subthreshold Gilbert multiplier. The frequency of oscillation of an oscillating signal within the LC tank circuit changes according to a control voltage applied to the Gilbert multiplier.