Spread spectrum clock and reference signal generator
First Claim
1. An apparatus, comprising:
- a reference oscillator to provide a reference signal having a reference frequency;
a coefficient register to store a plurality of coefficients;
a plurality of controlled reactance modules coupled to the coefficient register, each controlled reactance module responsive to a corresponding coefficient of the plurality of coefficients to modify an effective reactance of the reference oscillator; and
a spread spectrum controller comprising a counter and a state machine, the counter to provide a plurality of time interval counts and the state machine, in response to a predetermined time interval count of the plurality of time interval counts, to select or modify a plurality of coefficients from the coefficient register to generate a spread spectrum reference signal at a plurality of different reference frequencies over a predetermined time period.
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Abstract
Exemplary embodiments of the invention provide a system, method and apparatus for spread spectrum functionality for a free-running, reference harmonic oscillator. In an exemplary embodiment, an apparatus comprises a reference oscillator adapted to provide a reference signal having a reference frequency; and a spread spectrum controller adapted to control the reference oscillator to generate a spread-spectrum reference signal at a plurality of different reference frequencies during a predetermined or selected time period. An exemplary apparatus may also include a coefficient register adapted to store a plurality of coefficients and a plurality of controlled reactance modules responsive to a corresponding coefficient of the plurality of coefficients to modify an amount of reactance effectively coupled to the reference oscillator. An exemplary spread spectrum controller is further adapted to sequentially modify the plurality of coefficients during the predetermined time period to provide the spread spectrum reference signal.
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Citations
88 Claims
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1. An apparatus, comprising:
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a reference oscillator to provide a reference signal having a reference frequency; a coefficient register to store a plurality of coefficients; a plurality of controlled reactance modules coupled to the coefficient register, each controlled reactance module responsive to a corresponding coefficient of the plurality of coefficients to modify an effective reactance of the reference oscillator; and a spread spectrum controller comprising a counter and a state machine, the counter to provide a plurality of time interval counts and the state machine, in response to a predetermined time interval count of the plurality of time interval counts, to select or modify a plurality of coefficients from the coefficient register to generate a spread spectrum reference signal at a plurality of different reference frequencies over a predetermined time period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. An apparatus, comprising:
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a reference resonator to provide a reference signal having a resonant frequency; a coefficient register to store a plurality of coefficients; a plurality of controlled reactance modules coupled to the reference resonator and to the coefficient register; and a spread spectrum controller coupled to the coefficient register, the spread spectrum controller comprising a counter and a state machine, the counter to provide a plurality of time interval counts; and
the state machine, in response to a predetermined time interval count of the plurality of time interval counts, to select or modify a plurality of coefficients from the coefficient register to provide the reference signal at a plurality of different resonant frequencies during a selected or predetermined time period. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 74)
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65. A spread spectrum clock generator comprising:
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a reference oscillator to provide a reference signal having a reference frequency; a coefficient register to store a plurality of coefficients; a plurality of controlled reactance modules coupled to the reference oscillator and to the coefficient register, each controlled reactance module responsive to a corresponding coefficient of the plurality of coefficients to modify an amount of effective reactance coupled to the reference oscillator; and a spread spectrum controller comprising a counter, an adder and a state machine, the counter to provide a plurality of time interval counts and the state machine, in response to a predetermined time interval count of the plurality of time interval counts, to select or modify a plurality of coefficients from the coefficient register to control the reference oscillator to generate a reference signal at a plurality of different reference frequencies. - View Dependent Claims (66, 67, 68, 69, 70, 71, 72)
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73. A method of spread-spectrum clock generation, comprising:
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generating a reference signal from a reference oscillator; counting the reference signal to provide a plurality of time interval counts; and modifying a plurality of coefficients to modify an amount of reactance effectively coupled to the reference oscillator at a plurality of predetermined time interval counts of the plurality of time interval counts to generate a spread-spectrum reference signal at a plurality of different reference frequencies during a predetermined time period. - View Dependent Claims (75, 76, 77, 78, 79, 80, 81, 82, 83, 84)
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85. A spread spectrum controller couplable to a reference oscillator, the reference oscillator to provide a reference signal having a reference frequency, the spread spectrum controller comprising:
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a memory to store a plurality of coefficients and a plurality of increment values; and a controller comprising a counter, an adder and a state machine, the counter to provide a plurality of time interval counts, and the state machine, in response to a predetermined time interval count of the plurality of time interval counts, to signal the adder to add a corresponding increment value, of the plurality of increment values, to the plurality of coefficients to provide a next plurality of coefficients to the coefficient register to control the reference oscillator to generate a spread-spectrum reference signal at a plurality of different reference frequencies during a predetermined time period. - View Dependent Claims (86, 87, 88)
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Specification