| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a local oscillation circuit the power consumption of which can be reduced. <P>SOLUTION: In the local oscillation circuit including: a phase comparator 1 for comparing a phase of a reference oscillation signal having a frequency fs with a phase of a frequency division signal having a frequency fout/(m×n); a charge pump 10 for outputting a current IOUT in response to a deviation of the phases of both the signals; a loop filter 3 for generating a control voltage VC in response to the output current IOUT; a voltage-controlled oscillator 4 for outputting the signal with the oscillated frequency fout in response to the control voltage VC; and a pre-stage frequency divider 5 and a variable counter 6 for frequency-dividing an output signal from the voltage-controlled oscillator 4 by a frequency division value (m×n) in response to the setting frequency and outputting the frequency division signal, wherein the oscillated frequency fout is locked to the setting frequency, the charge pump 10 switches the value of the output current IOUT depending on the setting frequency. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
