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World Academy of Science, Engineering and Technology 55 2009 A Capacitive Sensor Interface Circuit Based on Phase Differential Method H. Phase Detector Circuit A phase detector circuit is a frequency mixer or analog multiplier circuit. Charge Pump Circuits Charge pump circuit is a circuit consists of current source component and current sink component. In this design, type IV of phase frequency detector circuit is used together with charge pump and low pass filter to produce DC voltage proportional to phase difference.
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