Patent ID: 7013119

Claim:
A radio communication apparatus for carrying out reception processing of a radio signal which is transmitted intermittently at specified time intervals, said radio communication apparatus comprising: a first oscillator for generating an operation clock signal used for the reception processing of the radio signal; a second oscillator for generating a timing clock signal with a predetermined frequency lower than the frequency of the operation clock signal; a frequency deviation measuring duration controller for determining a deviation measuring duration of measuring a frequency deviation of the timing clock signal in accordance with an intermittent time interval of the radio signal; a frequency deviation measuring section for measuring the frequency deviation of the timing clock signal in response to the operation clock signal over the deviation measuring duration; and a timing counter for correcting the frequency deviation of the timing clock signal, for measuring an intermittent span of the received signal in response to the timing clock signal after the correction, and for starting said first oscillator in synchronization with an estimated reception timing of the radio signal.