Patent ID: 7590400

Claim:
A radio apparatus for repeatedly transmitting and receiving a predetermined number of slots with a plurality of radio frequency signals available in a radio system band and data communication using a blank slot, comprising: a phase synchronizing circuit having: a phase comparator for generating a voltage corresponding to the phase difference between the phase of a reference signal and the phase of a comparing frequency divided signal, and a voltage controlling oscillator for generating a frequency corresponding to a control voltage; a first loop filter for causing said phase synchronizing circuit to perform a phase synchronizing operation at a predetermined speed; a second loop filter for causing said phase synchronizing circuit to perform the phase synchronizing operation at a higher speed than the predetermined speed; and a loop filter selecting means for connecting said first loop filter to said voltage controlling oscillator in the period of one of the slots that is used for a communication and for connecting said second loop filter to said voltage controlling oscillator when the period of the slot is over.