Systems and methods for locking an oscillator to an incoming data signal
First Claim
1. A system comprising:
- an oscillator adapted to provide an oscillator signal;
a frequency divider adapted to divide the oscillator signal to provide a divided oscillator signal;
a phase-frequency detector adapted to provide phase-frequency detection signals in response to a reference clock signal and to the divided oscillator signal;
a charge pump adapted to provide first output signals in response to the phase-frequency detection signals;
a phase detector adapted to provide phase detection signals in response to an incoming data signal and to the oscillator signal;
adjustable resistors adapted to provide second output signals in response to the phase detection signals;
one or more switches adapted to pass the first output signals during a frequency acquisition mode and pass the second output signals during a phase lock mode wherein no charge pump is used in providing the second output signals during the phase lock mode; and
an active filter adapted to filter the passed first or the passed second output signals, wherein the oscillator is adapted to adjust a frequency of the oscillator signal in response to the filtered first or the filtered second output signals.
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Abstract
In one example, a system includes an oscillator adapted to provide an oscillator signal, a frequency divider adapted to divide the oscillator signal to provide a divided oscillator signal, and a phase-frequency detector adapted to provide phase-frequency detection signals in response to a reference clock signal and the divided oscillator signal. The system also includes a charge pump adapted to provide first output signals in response to the phase-frequency detection signals, a phase detector adapted provide second output signals in response to an incoming data signal and the oscillator signal, and one or more switches adapted to pass the first output signals during a frequency acquisition mode and pass the second output signals during a phase lock mode. The system also includes an active filter adapted to filter the passed first or second output signals. The oscillator is adapted to adjust a frequency of the oscillator signal in response to the filtered first or second output signals.
32 Citations
19 Claims
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1. A system comprising:
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an oscillator adapted to provide an oscillator signal; a frequency divider adapted to divide the oscillator signal to provide a divided oscillator signal; a phase-frequency detector adapted to provide phase-frequency detection signals in response to a reference clock signal and to the divided oscillator signal; a charge pump adapted to provide first output signals in response to the phase-frequency detection signals; a phase detector adapted to provide phase detection signals in response to an incoming data signal and to the oscillator signal; adjustable resistors adapted to provide second output signals in response to the phase detection signals; one or more switches adapted to pass the first output signals during a frequency acquisition mode and pass the second output signals during a phase lock mode wherein no charge pump is used in providing the second output signals during the phase lock mode; and an active filter adapted to filter the passed first or the passed second output signals, wherein the oscillator is adapted to adjust a frequency of the oscillator signal in response to the filtered first or the filtered second output signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method comprising:
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providing an oscillator signal using an oscillator; dividing the oscillator signal using a frequency divider to provide a divided oscillator signal; providing phase-frequency detection signals from a phase-frequency detector in response to a reference clock signal and to the divided oscillator signal; providing first output signals from a charge pump in response to the phase-frequency detection signals; providing phase detection signals from a phase detector in response to an incoming data signal and to the oscillator signal; providing second output signals from one or more adjustable resistors in response to the phase detection signals; switching between passing the first output signals during a frequency acquisition mode and passing the second output signals during a phase lock mode wherein no charge pump is used in providing the second output signals the during phase lock mode; and filtering the passed first or the passed second output signals using an active filter, wherein the oscillator is adapted to adjust a frequency of the oscillator signal in response to the filtered first or the filtered second output signals. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A system comprising:
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means for providing an oscillator signal; means for dividing the oscillator signal to provide a divided oscillator signal; means for providing phase-frequency detection signals in response to a reference clock signal and to the divided oscillator signal; means for providing first output signals from a charge pump in response to the phase-frequency detection signals; means for providing phase detection signals in response to an incoming data signal and to the oscillator signal; means for providing second output signals from one or more adjustable resistors in response to the phase detection signals; means for switching between passing the first output signals during a frequency acquisition mode and passing the second output signals during a phase lock mode wherein no charge pump is used in providing the second output signals during the phase lock mode; means for filtering the passed first or the passed second output signals; and means for adjusting a frequency of the oscillator signal in response to the filtered first or the filtered second output signals.
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Specification