| 摘要 |
A voltage controlled oscillator (8) comprises an LPF charging circuit (11) constituted by connecting a plurality of variable delay circuits (30) in a ring shape and fixing the input voltage to the voltage controlled oscillator (8) at a predetermined high level when operation of the voltage controlled oscillator (8) is stopped, and an output fixing section (31) for fixing the output from the variable delay circuits (30). Since the output from the variable delay circuits (30) is fixed by the output fixing section (31) even if operation of the voltage controlled oscillator following up the frequency of an input clock is stopped, the output from the voltage controlled oscillator (8) does not enter an unstable stable. Accordingly, the voltage controlled oscillator (8) can be oscillated normally when operation thereof is restarted or started.
|
