| 摘要 |
PURPOSE: A self-noise removal voltage controlling oscillator is provided to reduce the noises of a ring oscillator by forming a negative feedback loop with the ring oscillator, a divider, and a frequency to voltage transformer. CONSTITUTION: A phase frequency detector(100) outputs an up-signal or a down-signal according to the phase difference of an input clock and a feedback clock. A charge pump(200) outputs a current which is proportional to the up-signal and the down-signal which are outputted in the phase frequency detector. A loop filter(300) outputs a voltage by smoothing the current which is outputted in the charge pump. A voltage controlling oscillator(400) outputs a frequency based on the voltage outputted in the loop filter. A divider(500) divides the output frequency of a voltage control phase delay part. A frequency to voltage transformer(600) eliminates the noises of the voltage controlling oscillator by feeding back the voltage corresponding to the frequency, which is divided in the divider, to the voltage controlled oscillator . |
