摘要 |
<p>An oscillating signal of a VCO (7), after being divided by a divider (2), is input by a phase comparator (3). The phase difference between the divider (2) and a reference signal is detected by the phase comparator (3), and phase error is smoothed by a loop filter (4) to yield a phase error signal. The oscillating signal of the VCO 7 is also input by a frequency detector (9) and is detected to determine whether it is equal to a predetermined value or in a predetermined range. On the basis of this detection result, a frequency error signal is output. The frequency error signal and the phase error signal, after being added together, are input by the VCO (7) as a control signal so that the oscillation frequency is controlled. <IMAGE></p> |