Phase-locked loop for stably adjusting frequency-band of voltage-controlled oscillator and phase locking method
First Claim
1. A phase-locked loop comprising:
- a basic phase-locked loop circuit comprising a voltage-controlled oscillator (VCO), the basic phase-locked loop circuit generating an output clock signal which is phase-locked with an input clock signal using the VCO which oscillates in response to an oscillation control signal and changes an oscillation frequency band depending on a frequency band selection digital value; and
a frequency band controller which generates the frequency band selection digital value in response to the input clock signal and the oscillation control signal.
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Abstract
A phase-locked loop (PLL) for stably adjusting a frequency band of a voltage-controlled oscillator and a phase locking method. In the PLL, a frequency band controller alters the frequency band selection digital value in response to an input clock signal and an oscillation control signal generated from an LPF of a basic PLL circuit, and thus a voltage-controlled oscillator of the basic PLL circuit alters the frequency of an output clock signal in response to the oscillation control signal and the frequency band selection digital value. The output clock signal is rapidly and stably phase-locked at a target frequency depending on the frequency band selection digital value.
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Citations
18 Claims
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1. A phase-locked loop comprising:
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a basic phase-locked loop circuit comprising a voltage-controlled oscillator (VCO), the basic phase-locked loop circuit generating an output clock signal which is phase-locked with an input clock signal using the VCO which oscillates in response to an oscillation control signal and changes an oscillation frequency band depending on a frequency band selection digital value; and
a frequency band controller which generates the frequency band selection digital value in response to the input clock signal and the oscillation control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of phase-locking an input clock signal using a voltage-controlled oscillator (VCO) which is operated in response to an oscillation control signal and a frequency band selection digital value, the method comprising:
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receiving the input clock signal;
processing, using the VCO, the input clock signal and an output clock signal which is fed back from the VCO to generate the oscillation control signal;
deciding the frequency band selection digital value in response to the input clock signal and the oscillation control signal; and
changing an oscillation frequency band of the VCO depending on the decided frequency band selection digital value to thereby generate the output clock signal having a frequency which is phase-locked at a certain target frequency. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A computer readable recording medium storing a program for implementing a method of phase-locking an input clock signal using a voltage-controlled oscillator (VCO) which is operated in response to an oscillation control signal and a frequency band selection digital value, the method comprising:
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receiving the input clock signal;
processing, using the VCO, the input clock signal and an output clock signal which is fed back from the VCO to generate the oscillation control signal;
deciding the frequency band selection digital value in response to the input clock signal and the oscillation control signal; and
changing an oscillation frequency band of the VCO depending on the decided frequency band selection digital value to thereby generate the output clock signal having a frequency which is phase-locked at a certain target frequency.
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Specification