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APPARATUS OF PHASE-FREQUENCY DETECTOR

  • US 20050025275A1
  • Filed: 04/07/2004
  • Published: 02/03/2005
  • Est. Priority Date: 04/10/2003
  • Status: Active Grant
First Claim
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1. A phase-frequency detector for adjusting a target clock signal and an input signal to the same phase comprising:

  • a first logic gate for receiving a first protection signal and a second protection signal, and for outputting a third protection signal according to a result of a corresponding logic arithmetic;

    a first flip-flop electrically connected to the first logic gate, the first flip-flop for receiving the third protection signal, and for outputting the third protection signal as a first output signal when triggered by the target clock signal;

    a second flip-flop electrically connected to the first logic gate, the second flip-flop for receiving the third protection signal, and for outputting the third protection signal as a second output signal when triggered by the input signal;

    a second logic gate electrically connected to the first flip-flop and the second flip-flop, the second logic gate for receiving the first output signal and the second output signal, and for outputting a fourth protection signal according to a result of a corresponding logic arithmetic; and

    a third logic gate electrically connected to the second logic gate, the third logic gate for receiving the third protection signal and the fourth protection signal, and for outputting a fifth protection signal according to a result of a corresponding logic arithmetic;

    wherein a logic level of the fifth protection signal is used to determine whether to compare the phase of the input signal and the phase of the target clock signal.

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