Patent ID: 8593227

Claim:
A circuit, comprising: a controllable oscillator; and a controller coupled to the controllable oscillator, wherein the controller is configured to provide a current control and a gain control to the controllable oscillator, wherein during a calibration process, the controller is configured to: adjust a current applied to the controllable oscillator so that a tuning signal applied to the controllable oscillator is within a tuning range; while applying the current to the controllable oscillator, apply at least two different reference signals to the controllable oscillator to determine a frequency difference of an output frequency of the controllable oscillator; further adjust the current applied to the controllable oscillator in response to the frequency difference; determine a gain of the controllable oscillator based on the frequency difference and a corresponding difference in the at least two different reference signals; adjust the gain of the controllable oscillator to a target gain; and further adjust the current while substantially maintaining the gain of the controllable oscillator at the target gain to calibrate the controllable oscillator to a particular frequency-voltage tuning range.