| 摘要 |
PROBLEM TO BE SOLVED: To shorten phase pull-in time when a frequency is almost matched but a phase is deviated almost >=90 deg. in a PLL circuit. SOLUTION: A >=90 deg. phase deviation detector 7 is provided for judging whether the phase is deviated almost >=90 deg. or not and when it is detected that the phase is deviated almost >=90 deg., by charging a current to a loop filter 5, a gain is equivalently increased rather than ordinary. Thus, pull-in time can be shortened. |
