| 摘要 |
A gm-C VCO oscillates at a frequency that corresponds to an input control voltage. A divider divides the frequency of an oscillation signal output from the gm-C VCO. A phase comparison signal generating unit generates a phase difference signal that corresponds to the phase difference between the oscillation signal thus frequency-divided by the divider and a reference clock signal. A loop filter performs filtering of the phase difference signal so as to generate the control voltage. A startup circuit injects a seed pulse into the gm-C VCO at a timing determined based upon the level of a detection signal that corresponds to the control voltage. |
