| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a phase synchronous circuit which satisfies both a high- speed locking (synchronization) and a stable normal state. <P>SOLUTION: The phase synchronous circuit, equipped with a branch circuit provided at a first filter of a loop filter for speeding a lock speed and an analog switch circuit for conducting connection or disconnection operation for this branch circuit, is configured so that a control signal is supplied via a D/A converter to conduct switching operation for the analog switch circuit. The analog switch circuit composed of a semiconductor element is configured so that a control signal, which varies continuously and intermittently with any number of variance and with any interval within the offset voltage range up to off state, is supplied via a D/A converter to conduct connection or disconnection operation for the branch circuit continuously and intermittently. <P>COPYRIGHT: (C)2003,JPO |
