SYNCHRONOUS FOLLOW-UP APPARATUS AND SYNCHRONOUS FOLLOW-UP METHOD

摘要

A synchronous follow-up apparatus includes a PLL portion that outputs a first clock signal, and a control loop portion. The control loop portion includes a reference frequency signal generating portion that outputs a reference frequency signal, a clock signal generating portion that generates a second clock signal having the same frequency as a frequency of the first clock signal based on the reference frequency signal generated by the reference frequency signal generating portion, and a frequency control signal generating portion that generates a frequency control signal to change the frequency of the second clock signal based on a frequency difference between the first clock signal and the second clock signal that occurs after a predetermined time and outputs the frequency control signal to the clock signal generating portion.