There is provided a clock-recovering filter circuit for use in a clock
recovery circuit that generates a recovery clock signal from input data
from an external device and a reference clock signal. The filter circuit
includes: a pulse-inserting circuit which inserts pulses in a first
phase-advancing signal or a first phase-delaying signal, thereby
generating a second phase-advancing signal or a second phase-delaying
signal; and a frequency-offset detecting circuit which detects
frequency-offset data from the second phase-advancing signal and the
second phase-delaying signal, the frequency-offset data representing a
frequency difference between the recovery clock signal and the reference
clock signal. The pulse-inserting circuit inserts pulses in accordance
with the frequency-offset data when the first phase-advancing signal or
the first phase-delaying signal is not input.