| 摘要 |
PURPOSE:To obtain a phase locked loop in which quick lock-in is attained and whose jitter is reduced by applying a voltage to a voltage controlled oscillator as its center voltage after application of power to one terminal of a capacitive element and supplying the output of the other terminal with respect to the center voltage so as to detect the phase difference. CONSTITUTION:An output amplitude is supplied around the divided voltage of resistive elements 101, 102 at the first phase comparison after application of power and a loop filter output voltage change at the phase detection is set optionally by selecting resistive elements 103, 104 and a capacitive element 107 or the like and the current of current sources 108, 111. Thus, the divided voltage by the elements 101, 102 is set to the center voltage of the voltage controlled oscillator to approach the voltage controlled oscillator to a lock-in state immediately by using a first phase difference signal after application of power. Further, the tracking characteristic of the phase locked loop is set optionally by adjusting the change in the loop filter output voltage at the detection of phase difference. |
