FREQUENCY SYNTHESIZER AND FAST AUTOMATIC CALIBRATION DEVICE THEREFOR

摘要

PURPOSE: A frequency combiner and a fast automatic correcting device therefor are provided to calculate the difference between an output frequency and a target frequency, thereby increasing frequency correction speed. CONSTITUTION: A frequency-digital converting unit(320) converts the frequency of a signal which is outputted from a voltage controlled oscillator into a first digital value. A frequency difference detecting unit(402) calculates the difference between the first digital value and a second digital value corresponding to a target frequency. An automatic frequency correcting unit(404) selects the optimum control code of a cap bank to make the output frequency of the voltage controlled oscillator close to the target frequency. A loop bandwidth correcting unit(406) adjusts a charge pump gain to uniformly maintain the loop bandwidth in the optimum control code.