DIGITAL VCO AND PLL CIRCUIT USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a digital VCO capable of setting a frequency of its output signal to a desired frequency even against manufacturing dispersion of elements in use, variations in temperature characteristics of the components, and fluctuations in a power supply voltage.

SOLUTION: The digital VCO is configured to include an analog / digital converter 11 (conversion circuit) converting a given analog signal into a digital signal; a crystal oscillation circuit 12 (crystal vibrator) provided with the crystal vibrator and generating a signal with a prescribed frequency; and a variable frequency divider circuit 13 (frequency divider circuit) whose frequency division ratio is varied on the basis of the digital signal and frequency-dividing a signal generated by the crystal oscillation circuit 12 on the basis of the frequency division ratio.

COPYRIGHT: (C)2004,JPO