| 摘要 |
PURPOSE:To eliminate noise (reference leakage) caused by on/off of a sampling analog switch in the sample-and-hold type phase comparator. CONSTITUTION:The two sample-and-hold type phase comparators of the entirely same configuration and unified performance are provided. On one hand, a voltage VA corresponding to a phase difference between a reference signal REF and a phase-compared signal SIG is outputted. On the other hand, a voltage VB corresponding to a phase difference between the reference signal REF and a signal REF' delayed by a prescribed value is outputted. A voltage difference V0 between the voltages VA and VB is obtained by a subtractor 2 and used as the circuit output. Through the subtraction, a reference signal leakage due to field-through of an analog switch 10 is eliminated. |
