Lineariser for a signal handling apparatus
First Claim
1. Apparatus for generating a predistorted signal from an input signal to reduce distortion in an output signal generated by signal handling equipment based on the predistorted signal, the apparatus comprising:
- an extractor adapted to generate an extracted signal from the input signal;
a generator adapted to generate a distortion signal based on the extracted signal, wherein the distortion signal comprises;
a second-order distortion component based on a second-order signal generated from the extracted signal; and
a fourth-order distortion component based on a fourth-order signal generated from the extracted signal; and
a modulator adapted to modulate the input signal based on the distortion signal to generate the predistorted signal.
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Accused Products
Abstract
A lineariser (100) for reproducing distortion present in the output of an amplifier (110) (or other signal handling device) generates a predistortion signal from the amplifier input. The predistortion signal is mixed into the amplifier input signal using, for example, a vector modulator (112). The predistortion signal may be derived in a quadrature format, the orthogonal components of the predistortion signal being mixed into separate mixers of the vector modulator. The predistortion signal is generated by multiplying the input signal with itself repeatedly to generate components of distortion which are susceptible of independent control. The predistortion signal is generated digitally using DSP (116). A multiplier or mixer may be used to square the sampled input signal to produce a reduced frequency signal which the DSP can use to gennerate the predistortion signal. Another lineariser mixes the predistortion signal into the input signal during up conversion.
114 Citations
52 Claims
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1. Apparatus for generating a predistorted signal from an input signal to reduce distortion in an output signal generated by signal handling equipment based on the predistorted signal, the apparatus comprising:
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an extractor adapted to generate an extracted signal from the input signal; a generator adapted to generate a distortion signal based on the extracted signal, wherein the distortion signal comprises; a second-order distortion component based on a second-order signal generated from the extracted signal; and a fourth-order distortion component based on a fourth-order signal generated from the extracted signal; and a modulator adapted to modulate the input signal based on the distortion signal to generate the predistorted signal. - 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)
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25. A method for generating a predistorted signal from an input signal to reduce distortion in an output signal generated by signal handling equipment based on the predistorted signal, the method comprising:
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generating an extracted signal from the input signal; generating a distortion signal based on the extracted signal, wherein the distortion signal comprises; a second-order distortion component based on a second-order signal generated from the extracted signal; and a fourth-order distortion component based on a fourth-order signal generated from the extracted signal; and modulating the input signal based on the distortion signal to generate the predistorted signal. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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49. Apparatus for generating a predistorted signal from an input signal to reduce distortion in an output signal generated by signal handling equipment based on the predistorted signal, the apparatus comprising:
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means for generating an extracted signal from the input signal; means for generating a distortion signal based on the extracted signal, wherein the distortion signal comprises; a second-order distortion component based on a second-order signal generated from the extracted signal; and a fourth-order distortion component based on a fourth-order signal generated from the extracted signal; and means for modulating the input signal based on the distortion signal to generate the predistorted signal.
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50. Apparatus for generating a predistorted signal from an input signal to reduce distortion in an output signal generated by signal handling equipment based on the predistorted signal, the apparatus comprising:
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an extractor adapted to generate an extracted signal from the input signal; automatic gain control (AGC) circuitry adapted to condition the extracted signal so that the conditioned signal envelope maintains a substantially constant amplitude; a generator adapted to generate a distortion signal based on the conditioned signal; and a modulator adapted to modulate the input signal based on the distortion signal to generate the predistorted signal.
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51. A method for generating a predistorted signal from an input signal to reduce distortion in an output signal generated by signal handling equipment based on the predistorted signal, the method comprising:
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generating an extracted signal from the input signal; conditioning the extracted signal so that the conditioned signal envelope maintains a substantially constant amplitude; generating a distortion signal based on the conditioned signal; and modulating the input signal based on the distortion signal to generate the predistorted signal.
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52. Apparatus for generating a predistorted signal from an input signal to reduce distortion in an output signal generated by signal handling equipment based on the predistorted signal, the apparatus comprising:
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means for generating an extracted signal from the input signal; means for conditioning the extracted signal so that the conditioned signal envelope maintains a substantially constant amplitude; means for generating a distortion signal based on the conditioned signal; and means for modulating the input signal based on the distortion signal to generate the predistorted signal.
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Specification