Digital predistortion of signals
AssigneeApple Inc.
InventorsAndreas Langer, Christoph Hepp, Andreas Menkhoff, Gunther Kraut
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Abstract
Systems, circuitries, and methods for predistorting a digital signal in a transmit chain based on a predistortion function are provided. A method includes shifting a center frequency of an input signal by an offset to generate an adapted signal; predistorting the adapted signal based on a predistortion function to generate a predistorted adapted signal; reverting the shifting of the center frequency of the predistorted adapted signal by the offset to generate a predistorted signal; and causing transmission of the predistorted signal by a transmit chain.
Claims20
A method, comprising:
- shifting a center frequency of a first input signal by an offset to generate an adapted signal;
- predistorting the adapted signal based on a predistortion function to generate a predistorted adapted signal;
- reverting the shifting of the center frequency of the predistorted adapted signal by the offset to generate a predistorted signal,
- wherein the offset is based on a difference between a center frequency of a calibration signal used to derive the predistortion function and a center frequency of the first input signal;
- and
- causing transmission of the predistorted signal by a transmit chain.
A baseband processor, configured to:
- shift a center frequency of a first input signal by an offset to generate an adapted signal;
- predistort the adapted signal based on a predistortion function to generate a predistorted adapted signal;
- revert the shifting of the center frequency of the predistorted adapted signal by the offset to generate a predistorted signal,
- wherein the offset is based on a difference between a center frequency of a calibration signal used to derive the predistortion function and a center frequency of the first input signal;
- and
- cause transmission of the predistorted signal by a transmit chain.
A non-transitory computer-readable medium having executable instructions stored thereon that, when executed by a processor, cause the processor to perform corresponding functions comprising:
- shifting a center frequency of a first input signal by an offset to generate an adapted signal;
- predistorting the adapted signal based on a predistortion function to generate a predistorted adapted signal;
- reverting the shifting of the center frequency of the predistorted adapted signal by the offset to generate a predistorted signal,
- wherein the offset is based on a difference between a center frequency of a calibration signal used to derive the predistortion function and a center frequency of the first input signal;
- and
- causing transmission of the predistorted signal by a transmit chain.
Dependencies are inferred from the claim text.