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US 2013/0076547 A1Published application
Sigma-Delta Modulation with Reduction of Spurs Using a Dither Signal
AssigneeSilicon Laboratories Inc.
InventorAdam B. Eldredge
Life of this patent
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Abstract
A method includes operating on a sigma-delta modulated signal to reduce a dither signal component in one of a first signal and a second signal, the first signal being an integer portion corresponding to a digital frequency ratio and the second signal corresponding to a fractional portion of the digital frequency ratio. In at least one embodiment of the method, the operation is performed digitally in a frequency synthesizer.
Claims20
A method comprising:
- sigma-delta modulating a combination of a dither signal and an input signal to generate a first signal;
- sigma-delta modulating a signal based on the dither signal to generate a second signal;
- and
- generating a first control signal based on a difference between the first signal and the second signal.
1 more element
An apparatus comprising:
- a first sigma-delta modulator coupled to generate a first signal in response to a dither signal and an input signal;
- a second sigma-delta modulator coupled to generate a second signal in response to the dither signal;
- and
- a first circuit coupled to generate a first control signal based on a difference between the first signal and the second signal.
1 more element
A method comprising:
- operating on a sigma-delta modulated signal to reduce a dither signal component in one of a first signal and a second signal, the first signal being an integer portion corresponding to a digital frequency ratio and the second signal corresponding to a fractional portion of the digital frequency ratio.
Dependencies are inferred from the claim text.