Power amplifier time-delay invariant predistortion methods and apparatus
First Claim
1. A predistortion system for linearizing the output of a power amplifier comprising:
- a first receiver configured to receive a first signal representative of a radio frequency (RF) modulated signal;
a second receiver configured to receive a feedback signal representative of at least one nonlinear characteristic of a power amplifier;
a predistortion controller communicatively coupled with both the first receiver and the second receiver, the predistortion controller comprising at least one lookup table of a predetermined size; and
wherein the at least one lookup table is configured to respond to;
a first input derived from a difference between the square of a quadrature component of the first signal and the square of a quadrature component of the feedback signal, anda second input derived from a difference between the square of an in-phase component of the first signal and the square of an in-phase component of the feedback signal.
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Abstract
An embodiment of the invention is a time-delay invariant predistortion approach to linearize power amplifiers in wireless RF transmitters. The predistortion architecture is based on the stored-compensation or memory-compensation principle by using a combined time-delay addressing method, and therefore, the architecture has an intrinsic, self-calibrating time-delay compensation function. The predistortion architecture only uses a lookup table to conduct both the correction of non-linear responses of a power amplifier and the compensation of any time-delay effects presented in the same system. Due to the time-delay invariant characteristic, the predistortion design has a wider dynamic range processing advantage for wireless RF signals, and therefore can be implemented in multi-carrier and multi-channel wireless systems.
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Citations
8 Claims
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1. A predistortion system for linearizing the output of a power amplifier comprising:
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a first receiver configured to receive a first signal representative of a radio frequency (RF) modulated signal; a second receiver configured to receive a feedback signal representative of at least one nonlinear characteristic of a power amplifier; a predistortion controller communicatively coupled with both the first receiver and the second receiver, the predistortion controller comprising at least one lookup table of a predetermined size; and wherein the at least one lookup table is configured to respond to; a first input derived from a difference between the square of a quadrature component of the first signal and the square of a quadrature component of the feedback signal, and a second input derived from a difference between the square of an in-phase component of the first signal and the square of an in-phase component of the feedback signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification