| 摘要 |
A phase synchronization system includes, in addition to a phase comparator (1) and a phase synchronization circuit (4) which includes a low-pass filter (2) and a voltage-controlled oscillation circuit (3), a clock detection circuit (5) for detecting the clock signal from the outside, a phase coincidence discrimination circuit (6) for discriminating a phase coincidence condition at the phase synchronization circuit (4), an AND gate (7), and a stop/start control circuit (10) including a pair of flip-flop circuits (8 and 9). When an input of the clock signal (101) from the outside stops, oscillation of the voltage-controlled oscillation circuit (3) is stopped with control information from the stop/start control circuit (10). When the input of the clock signal (101) is resumed, a phase synchronization signal by the oscillation of the voltage-controlled oscillation circuit (3) is outputted to the outside via the AND gate (7) in the stop/start control circuit (10) after phase coincidence is discriminated by the phase coincidence discrimination circuit (6). <IMAGE> |
