Linear power amplification method and linear power amplifier
First Claim
1. A linear power amplifier comprising:
- a digital predistorter supplied with a digital transmission signal, for predistorting said digital transmission signal by use of a power series model to generate a predistorted signal;
a DA converter for converting said predistorted signal from said digital predistorter into an analog predistorted signal;
a frequency upconverting part for upconverting said analog predistorted signal to a transmit frequency band;
a power amplifier for power-amplifying said upconverted signal;
a frequency downconverting part for downconverting a portion of the output from said power amplifier to output a downconverted signal; and
a digital predistorter control part for extracting distortion components of the same odd orders as those of said power series model and for controlling coefficients of said predistorter in a manner to lower the levels of said odd-order distortion components.
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Accused Products
Abstract
A combined signal of a digital pilot signal and a digital transmission signal is applied to a digital predistorter (20), wherein it is added with odd-order distortions based on a power series model to generate a predistorted signal, then the predistorted signal is converted by a DA converter (31) to an analog signal, then the analog signal is upconverted by a frequency upconverting part (33) to a send frequency band, and the upconverted signal is output after being amplified by a power amplifier (37). A pilot signal component is extracted from the power amplifier output, then odd-order distortion components of the power series model are extracted by a digital predistorter control part (50) from the pilot signal component, and the odd-order distortions in the digital predistorter (20) are controlled to decrease the levels of the distortion components.
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Citations
36 Claims
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1. A linear power amplifier comprising:
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a digital predistorter supplied with a digital transmission signal, for predistorting said digital transmission signal by use of a power series model to generate a predistorted signal;
a DA converter for converting said predistorted signal from said digital predistorter into an analog predistorted signal;
a frequency upconverting part for upconverting said analog predistorted signal to a transmit frequency band;
a power amplifier for power-amplifying said upconverted signal;
a frequency downconverting part for downconverting a portion of the output from said power amplifier to output a downconverted signal; and
a digital predistorter control part for extracting distortion components of the same odd orders as those of said power series model and for controlling coefficients of said predistorter in a manner to lower the levels of said odd-order distortion components. - 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)
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32. A linear power amplification method comprising the steps of:
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(a) inputting a digital signal to a digital predistorter, and adding said digital signal with a predetermined number of odd-order distortion components based on a power series model to generate a predistorted signal;
(b) converting said predistorted signal to an analog predistorted signal;
(c) upconverting said analog predistorted signal to a send frequency band by use of a predetermined carrier frequency;
(d) power amplifying said upconverted signal;
(e) downconverting a portion of said power-amplified output signal to extract odd-order distortion components; and
(f) controlling coefficients of said digital predistorter so that the level ratios of said odd-order distortion components to a transmission signal each become smaller than a predetermined value. - View Dependent Claims (33, 34, 35, 36)
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Specification