Patent ID: 9621174
Date: 2017-04-11
CPC Classifications: H03B,H03L

Claim:
1. A frequency calibration method for calibrating an output frequency of a voltage-controlled oscillator, wherein the voltage-controlled oscillator comprises a first capacitor bank, a second capacitor bank, and a third capacitor bank, wherein a capacitance of one capacitor unit in the second capacitor bank is lower than a capacitance of one capacitor unit in the first capacitor bank and the capacitance of one capacitor unit in the second capacitor bank is greater than a capacitance of one capacitor unit in the third capacitor bank, the method comprising: turning off the first capacitor bank and the third capacitor bank; turning on the second capacitor bank; adjusting the output frequency of the voltage-controlled oscillator by controlling a number of enabled unit capacitors in the second capacitor bank; determining whether an output frequency is greater than a reference frequency; stopping adjustment of a number of enabled unit capacitors in the first capacitor bank when the output frequency is lower than the reference frequency; and adjusting the output frequency by controlling the number of enabled unit capacitors in the second capacitor bank until the output frequency is greater than the reference frequency.