Fractional PLLs with low correlation
First Claim
1. A method of decorrelating quantization noise generated by a plurality of frequency programmable phase-locked loops (PLLs), the method comprising:
- generating a first modulated data stream based on a first frequency control word, the first frequency control word configured to control a first frequency output by at least some of the plurality of PLLs;
generating a first data stream based on the first modulated data stream;
shifting the first modulated data stream by a first time shift to generate a second data stream;
applying the first data stream to a first PLL of the plurality of PLL to produce, at an output of the first PLL, a first output signal at the first frequency and having a first quantization noise component; and
applying the second data stream to a second PLL of the plurality of PLLs to produce, at an output of the second PLL, a second output signal at the first frequency and having a second quantization noise component decorrelated from the first quantization noise component.
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Accused Products
Abstract
The programmable frequency control system presented herein provides frequency programmability and phase noise reduction for signals generated by a plurality of frequency programmable phase-locked loops (PLLs). In general, a modulated data stream input to each of the plurality of PLLs controls the frequency of the signal output by the PLLs. The solution presented herein reduces the phase noise by introducing a time shift to the modulated data stream applied to at least some of the PLLs so that at least some of the PLLs receive time-shifted versions of the modulated data stream relative to other PLLs. In so doing, the solution presented herein decorrelates the quantization noise generated by the plurality of frequency programmable PLLs.
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Citations
20 Claims
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1. A method of decorrelating quantization noise generated by a plurality of frequency programmable phase-locked loops (PLLs), the method comprising:
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generating a first modulated data stream based on a first frequency control word, the first frequency control word configured to control a first frequency output by at least some of the plurality of PLLs; generating a first data stream based on the first modulated data stream; shifting the first modulated data stream by a first time shift to generate a second data stream; applying the first data stream to a first PLL of the plurality of PLL to produce, at an output of the first PLL, a first output signal at the first frequency and having a first quantization noise component; and applying the second data stream to a second PLL of the plurality of PLLs to produce, at an output of the second PLL, a second output signal at the first frequency and having a second quantization noise component decorrelated from the first quantization noise component. - View Dependent Claims (2, 3, 4, 5)
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6. A programmable frequency control system for controlling a plurality of frequency programmable phase-locked loops (PLLs), the programmable frequency control system comprising:
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a modulator configured to generate a first modulated data stream based on a first frequency control word input to the modulator, the first frequency control word configured to control a first frequency output by at least some of the plurality of PLLs; and a delay circuit operatively coupled to an output of the modulator and configured to; generate a first data stream based on the first modulated data stream; shift the first modulated data stream by a first time shift to generate a second data stream; apply the first data stream to a first PLL of the plurality of PLLs to produce, at an output of the first PLL, a first output signal at the first frequency and having a first quantization noise component; and apply the second data stream to a second PLL of the plurality of PLLs to produce, at an output of the second PLL, a second output signal at the first frequency and having a second quantization noise component decorrelated from the first quantization noise component. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. A computer program product stored in a non-transitory computer readable medium for decorrelating quantization noise produced by a plurality of frequency programmable phase-locked loops (PLLs), the computer program product comprising software instructions which, when run in a wireless control circuit, causes the wireless control circuit to:
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generate a first modulated data stream based on a first frequency control word, the first frequency control word configured to control a first frequency output by at least some of the plurality of PLLs; generate a first data stream based on the first modulated data stream; shift the first modulated data stream by a first time shift to generate a second data stream; apply the first data stream to a first PLL of the plurality of PLLs to produce, at an output of the first PLL, a first output signal at the first frequency and having a first quantization noise component; and apply the second data stream to a second PLL of the plurality of PLLs to produce, at an output of the second PLL, a second output signal at the first frequency and having a second quantization noise component decorrelated from the first quantization noise component.
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16. A beamforming system comprising a programmable frequency control system for controlling a plurality of frequency programmable phase-locked loops (PLLs), the programmable frequency control system comprising:
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a modulator configured to generate a first modulated data stream based on a first frequency control word input to the modulator, the first frequency control word configured to control a first frequency output by at least some of the plurality of PLLs; and a delay circuit operatively coupled to an output of the modulator and configured to; generate a first data stream based on the first modulated data stream; shift the first modulated data stream by a first time shift to generate a second data stream; apply the first data stream to a first PLL of the plurality of PLLs to produce, at an output of the first PLL, a first output signal at the first frequency and having a first quantization noise component; and apply the second data stream to a second PLL of the plurality of PLLs to produce, at an output of the second PLL, a second output signal at the first frequency and having a second quantization noise component decorrelated from the first quantization noise component. - View Dependent Claims (17, 18, 19, 20)
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Specification