Patent ID: 7421052

Claim:
An apparatus, comprising: a frequency adjustor to adjust a frequency of a quadrature voltage controlled oscillator, wherein the frequency adjustor comprises (i) at least one variable bias current source to provide a fine frequency adjustment and (ii) a plurality of capacitors, selectable based on a multi-bit digital control signal, to provide a course frequency adjustment; and selection logic to adjust the multi-bit digital control signal based on a received indication of the oscillator's frequency, wherein the selection logic comprises: a first counter to count pulses in a reference signal and to generate a first overflow signal when a first pre-determined number of pulses are counted, a second counter to count pulses in the received indication of the oscillator's frequency and to generate a second overflow signal when a second pre-determined number of pulses are counted, a skew detector coupled to the first and second counters to determine, based on the first and second overflow signals, if the frequency of the received indication differs from the frequency of the reference signal by more than a threshold amount, a direction detector coupled to the first and second counters to determine, based on the overflow signals, if the frequency of the received indication is greater than or less than the frequency of the reference signal, and a state machine to receive a skew bit from the skew detector and a direction bit from the direction detector and to adjust the digital control signal based on the two received bits.