| 摘要 |
PURPOSE:To form a phase locked loop circuit operated always stably by selected the time width of a 1st pulse signal to be a half of one period of the output signal of a voltage controlled oscillator in a phase locked loop circuit having the voltage controlled oscillator, a phase comparator and a filter. CONSTITUTION:An output signal Tc goes to an H level at the rise of an input pulse signal 100 and goes to an L level at the fall of an inverting output signal 300 coming succeedingly. Simultaneously a TS signal goes to H in this timing and the output signal Tc goes to an L level at the rise of an output signal 200 coming succeedingly. When a phase comparator 21 is operated in such a manner, the pulse width of signals TS, TD is a half the output signal period independently of the duty of the output signal 200 and the inverting output signal 300. Thus, the output current characteristic of a smooting filter 12 with respect to the phase difference between the input pulse signal 100 and the output signal 200 is stable independently of the duty of the output signal of the voltage controlled oscillator 14. |
