| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a wide-band modulation PLL with proper modulation accuracy, at a low cost. <P>SOLUTION: To a PLL part provided with a VCO 21, a frequency divider 22, a phase comparator 23 and a loop filter 24, modulation is applied, by controlling the frequency division ratio of the frequency divider 22 with a frequency division ratio generation part 29, and the control voltage of the VCO 21 by a control signal generating part 30. The VCO 21 is provided with two control terminals, and the control signal generation part 30 inputs control signals to one of the control terminals. When a modulation degree is adjusted, data f<SB>c1</SB>for calibration are inputted to the frequency division ratio generating part 29 and data f<SB>c2</SB>for the calibration are inputted to the control signal generating part 30. A demodulator 31 demodulates the output signals of the VCO 21, when each of the data for the calibration is inputted, and a modulation degree adjusting means 32 outputs modulation degree adjusting signals to the control signal generation part 30, on the basis of demodulation signals. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
