Phase-locked loop with analog phase rotator
First Claim
1. A phase-locked loop, comprising:
- a phase detector receiving an input signal and a first internal periodic signal and providing a phase signal indicative of a phase difference between said input signal and said first internal periodic signal;
a rotator receiving said phase signal and providing a first periodic signal and a second periodic signal each having a period being a function of said phase difference, said first and said second periodic signals being 90 degrees out of phase relative to each other said rotator further comprising an enforcer which adjusts the amplitudes of the first periodic signal and the second periodic signal to within predetermined limits; and
an interpolator circuit linearly combining said first and second periodic signals with a third periodic signal and a fourth periodic signal to provide said first internal periodic signal.
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Abstract
A phase-locked loop includes a phase detector which receives an input signal and a first internal periodic signal and provides a phase signal indicative of a phase difference between the input signal and the internal signal. A rotator then receives the phase signal and provides first and second periodic signals each having a frequency that is a function of the phase difference, the first and second periodic signals being 90 degrees out of phase with each other. An interpolator circuit then linearly combines the first and second periodic signals with third and fourth periodic signals to provide the first internal periodic signal. The interpolator circuit may provide a second internal periodic signal that is 90 degrees out of phase relative to the first internal periodic signal. The phase-locked loop may further include a low-pass filter provided between the phase detector and the rotator.
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Citations
24 Claims
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1. A phase-locked loop, comprising:
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a phase detector receiving an input signal and a first internal periodic signal and providing a phase signal indicative of a phase difference between said input signal and said first internal periodic signal;
a rotator receiving said phase signal and providing a first periodic signal and a second periodic signal each having a period being a function of said phase difference, said first and said second periodic signals being 90 degrees out of phase relative to each other said rotator further comprising an enforcer which adjusts the amplitudes of the first periodic signal and the second periodic signal to within predetermined limits; and
an interpolator circuit linearly combining said first and second periodic signals with a third periodic signal and a fourth periodic signal to provide said first internal periodic signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for providing a phase-locked loop, comprising:
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receiving an input signal and a first internal periodic signal and providing a phase signal indicative of a phase difference between said input signal and said first internal periodic signal;
receiving said phase signal and providing a first periodic signal and a second periodic signal each having a period being a function of said phase difference, said first and said second periodic signals being 90 degrees out of phase relative to each other;
adjusting the amplitudes of the first periodic signal and the second periodic signal to within predetermined limits; and
linearly combining said first and second periodic signals with a third periodic signal and a fourth periodic signal to provide said first internal periodic signal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification