Architecture and implementation methods of digital predistortion circuitry
First Claim
1. A predistorter configured for use with an RF power amplifier, the predistorter comprising:
- a vector modulator configured to receive an RF input signal and apply a correction thereto using correction factors;
a data structure coupled to the vector modulator and storing the correction factors;
the correction factors of the data structure compensating for amplitude and phase non-linearities in the responses of both the RF power amplifier and the vector modulator.
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Accused Products
Abstract
A predistorter including a modulator configured for use with an RF power amplifier or in an amplifier system that combines in a data structure correction factors for amplitude and phase non-linearities in the responses of the amplifier and the modulator. Correction factors for memory effects in the response of the RF power amplifier may also be calculated within the data structure from scale factors transferred into the data structure. Such a calculation may be based on a scaled polynomial. A circuit for applying the difference equation to the correction factors may also be included.
168 Citations
53 Claims
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1. A predistorter configured for use with an RF power amplifier, the predistorter comprising:
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a vector modulator configured to receive an RF input signal and apply a correction thereto using correction factors;
a data structure coupled to the vector modulator and storing the correction factors;
the correction factors of the data structure compensating for amplitude and phase non-linearities in the responses of both the RF power amplifier and the vector modulator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An amplifier system, the system comprising:
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an RF power amplifier; and
a predistorter coupled to the RF power amplifier, the predistorter comprising;
a vector modulator configured to receive an RF input signal and apply a correction thereto using correction factors;
a data structure coupled to the vector modulator and storing the correction factors;
the correction factors of the data structure compensating for amplitude and phase non-linearities in the response of both the RF power amplifier and the modulator. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A circuit for use in a predistorter having first and second pairs of look-up tables, the circuit comprising:
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a subtracter coupled to the first and second pairs of look-up tables and configured to subtract a previous correction factor from the second pair of look-up tables from a current correction factor from the first pair of look-up tables;
a first delay circuit coupled intermediate the second pair of look-up tables and the subtracter and configured to delay correction factors from the second pair of look up tables;
a second delay circuit coupled to the subtracter and configured to delay the difference between the current and previous correction factors; and
a summer coupled to the second delay circuit and the second pair of look-up tables and configured to add the difference between the current and previous correction factors to a subsequent correction factor to arrive at a correction factor that is used to compensate for memory effects in an RF power amplifier.
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30. A data structure for use with an RF power amplifier comprising:
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look-up tables for storing correction factors that correct for memory effects in the RF power amplifier;
the data structure configured to use a polynomial to calculate the correction factors and populate the look-up tables. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A method of calibrating an amplifier system, the method comprising:
loading correction factors that correct for amplitude and phase non-linearities in the response of both an RF power amplifier and a modulator into a data structure. - View Dependent Claims (43, 44, 45, 46)
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47. A method of predistorting a signal applied to an RF power amplifier, the method comprising:
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storing correction factors that correct for non-linearities in the response of both an RF power amplifier and a vector modulator in a data structure;
receiving an RF input signal using the vector modulator;
sampling a portion of the RF input signal power;
selecting correction factors from the data structure based on a portion of the RF input signal; and
applying the correction factors to the RF input signal using the vector modulator. - View Dependent Claims (48, 49, 50, 51, 52, 53)
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Specification