| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a PLL circuit which shortens the lockup time and enhances the S/N ratio. <P>SOLUTION: After start of lockup action, switching means 25 and 26 are switched during the switching time by means of a switching control means 3; and based on the phase difference from a phase comparator 1, currents of different current values flow to a voltage controlled oscillator 5 via a low-pass filter 4, so the voltage controlled oscillator 5 can output the input signal of target frequency at a high speed, thus the PLL circuit can shorten the lockup time. <P>COPYRIGHT: (C)2004,JPO |
