Frequency synthesizer

Frequency synthesizer

  • CN 102,369,665 B
  • Filed: 03/30/2010
  • Issued: 06/27/2017
  • Est. Priority Date: 04/03/2009
  • Status: Active Grant
First Claim
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1. a kind of low-power frequency synthesizer circuit for wireless set, the condensating synthesizering circuit includes:

  • - digital controlled oscillator, is configured to produce the output signal with frequency, and frequency is controlled by being input into digital control word;

    - the feedback loop being connected between the output of digital controlled oscillator and input, is configured to the defeated of digital controlled oscillatorEnter and digital control word is provided, digital control word comes since the error obtained in incoming frequency control word and output signal;

    And- the duty cycle module being connected with digital controlled oscillator and feedback loop, is configured to produce multiple control signal, with inputThe setting section clock cycle of reference clock signal, digital controlled oscillator is periodically enabled and disables,Wherein, feedback loop includes counter module and phase difference module, and counter module is configured to when the digital controlled oscillator of enableWhen, cycle count to the output signal from digital controlled oscillator and provide output phase signal to phase difference module;

    PhaseDifference module is configured to receive incoming frequency control word and output phase signal, and it is digital control to determine to provide error signal outputWord, andWherein, duty cycle module is configured to, when digital controlled oscillator is enabled using one of the multiple control signal, resetCounter;

    Wherein, feedback loop is configured to, in response to a signal in the multiple control signal, store digital control word;

    And withAfterwards when digital controlled oscillator is enabled, use stored digital control word to control digital controlled oscillator.

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