| 摘要 |
<P>PROBLEM TO BE SOLVED: To shorten a lockup time when operation conditions of a PLL circuit are changed. <P>SOLUTION: When a channel frequency is changed or when an operation is returned from an intermittent operation, a voltage and temperature detecting circuit 5 supplies a control voltage signal corresponding to a source voltage and an ambient temperature to an LPF 4 and a VCO 2 by switches 12 and 13 under the control of a control circuit 3. Then the control circuit 3 resets frequency-dividing operations of a reference frequency-dividing circuit 8 and a variable frequency-dividing circuit 6 so that phases match each other at a phase comparator 9. Consequently, the lockup time can be shortened by previously matching the frequency of the VCO 2 and phases of input signals of the phase comparator 9. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
