FREQUENCY CALIBRATION FOR A MONOLITHIC CLOCK GENERATOR AND TIMING/FREQUENCY REFERENCE

摘要

The invention provides a system method for frequency calibration of a free-running, harmonic oscillator. A reference oscillator (920) provides a reference frequency. An exemplary system system comprises a harmonic oscillator (3100), a frequency divider (3150), a comparator (3110), and a reactance modulator (3130) . The oscillator comprises a plurality of switchable reactance modules and a coefficient register, and provides an oscillation signal having an oscillation frequency. The frequency divider provides an output frequency as a fraction of the oscillation frequency. The comparator compares the output and reference frequencies and provides a comparison signal when the output frequency is not substantially equal to the reference frequency. The reactance modulator determines and provides to the coefficient register a first plurality of coefficients to control switching of a first subset of the reactance modules to increase the reactance of the oscillator when the output frequency is greater than the reference frequency, and a second plurality of coefficients to control switching of a second subset of the reactance modules to decrease the reactance of the oscillator when the output frequency is less than the reference frequency.