Abstract: A communications apparatus and a frequency control method thereof, in that control of a reference frequency (local oscillator frequency) is made by feeding back a frequency offset estimate FOS to the voltage-controlled oscillator 103, and the frequency offset between sending and receiving frequencies is corrected by feeding back a frequency offset control value FOC which is based on a sending reference frequency command on downstream control data DCD to sending frequency offset control means 118, to control a sending reference frequency by using both a voltage-controlled oscillator 108 (a frequency control step) and sending frequency offset control means 118 (a sending frequency offset control step).

Abstract: In a broadcasting channel receiving system of cellular radio telephone system, a signal received through an antenna 5 is demodulated with a carrier frequency formed by a frequency synthesizer 2 in a demodulator 4, and the output of the latter 4 is applied to a signal receiver 3. In response to a request from a CPU 1, the signal receiver 3 applies the measurement result to the CPU 1. The CPU 1 performs the timing control of the receiving system. The CPU controls the timing of the signal receiver so that the measurement of receiving electric fields of a plurality of frequencies is repeated for every predetermined period of time which is shorter than the period of time of the burst transmission which the base station carries out every predetermined period of time.

Abstract: A communications apparatus and a frequency control method thereof, in that control of a reference frequency (local oscillator frequency) is made by feeding back a frequency offset estimate FOS to the voltage-controlled oscillator 103, and the frequency offset between sending and receiving frequencies is corrected by feeding back a frequency offset control value FOC which is based on a sending reference frequency command on downstream control data DCD to sending frequency offset control means 118, to control a sending reference frequency by using both a voltage-controlled oscillator 108 (a frequency control step) and sending frequency offset control means 118 (a sending frequency offset control step).