| 摘要 |
PROBLEM TO BE SOLVED: To reduce the power consumption of a radio communication apparatus using a frequency signal by a frequency synthesizer.SOLUTION: In the radio communication apparatus, a receiving section includes a first mixer for mixing a signal based on a received radio signal with a frequency signal, a second mixer for mixing an output of the first mixer with a local signal, and a demodulation stage for demodulating an output of the second mixer to generate a demodulation signal, a frequency synthesizer comprises a VCO for generating the frequency signal of a frequency responsive to a fluctuation in a control input voltage, and a feedback circuit for producing as the control input voltage a voltage depending on a phase difference between a signal obtained by frequency dividing an output frequency signal of the VCO and a reference clock signal, and the VCO is a variable frequency oscillator operable at a higher frequency with increasing bias current and the bias current is controlled in accordance with a mode designation. |
