Digital control of a linc linear power amplifier
First Claim
1. In a LINC power amplifier, an adaptive method for compensating for an unwanted difference between analog signal paths, comprising:
- (a) separating an input transmission signal into at least first and second component signals having envelopes of varying phase and substantially constant amplitude;
(b) amplifying the component signals along respective first and second analog signal paths;
(c) combining the component signals following amplification to produce an output signal;
(d) monitoring and digitally processing at least (i) the component signals prior to amplification, and (ii) the output signal, to generate compensation parameters; and
(e) modifying the first and second component signals prior to amplification thereof, based on the compensation parameters, to reduce distortion caused by said unwanted difference.
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Accused Products
Abstract
The inventive LINC amplifier provides substantially linear amplification from two nonlinear amplifiers by decomposing the original signal into two constant amplitude envelope, phase varying signals, which, when combined, constructively and destructively interfere to re-form the original signal. The output of the LINC amplifier, which is to be transmitted via an antenna, is an amplified form of the original signal. The inventive LINC amplifier utilizes a digital control mechanism to control and adapt a digital compensation network that directly compensates for the imperfections of the analog RF environment, including the amplifiers. The mechanism monitors the combined amplifier output and adjusts the signal components in order to precisely compensate for any differences in the characteristics of the separate signal paths which would cause the combination not to accurately represent the original signal. The mechanism also corrects the component signals using information which can be applied to the amplifiers independent of the signal to be transmitted.
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Citations
41 Claims
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1. In a LINC power amplifier, an adaptive method for compensating for an unwanted difference between analog signal paths, comprising:
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(a) separating an input transmission signal into at least first and second component signals having envelopes of varying phase and substantially constant amplitude; (b) amplifying the component signals along respective first and second analog signal paths; (c) combining the component signals following amplification to produce an output signal; (d) monitoring and digitally processing at least (i) the component signals prior to amplification, and (ii) the output signal, to generate compensation parameters; and (e) modifying the first and second component signals prior to amplification thereof, based on the compensation parameters, to reduce distortion caused by said unwanted difference. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A power amplifier which receives a bandlimited input transmission signal and provides an output transmission signal, wherein the output transmission signal is a substantially linear amplified representation of the input transmission signal, the amplifier comprising:
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a signal component separator that decomposes the input transmission signal into at least a first component signal and a second component signal, wherein each component signal has a substantially constant amplitude and a varying phase; first and second analog signal paths along which the first and second component signals are respectively amplified; a combiner that receives and combines the first and second component signals following amplification thereof to compose the output transmission signal; a compensation signal processor that digitally modifies at least one of the first component signal and the second component signal prior to amplification to compensate for unwanted differences between the first and second analog signal paths, the compensation signal processor modifying the at least one component signal based on compensation parameters; and a compensation estimator which adaptively generates the compensation parameters based on an observation of signals within the amplifier. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A power amplifier which receives an input transmission signal and provides an output transmission signal, wherein the output transmission signal is a substantially linear amplified representation of the input transmission signal, the amplifier comprising:
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means for separating the input transmission signal into a plurality of components signals, wherein each component signal has an amplitude envelope which varies in phase and is substantially constant in amplitude; means for adaptively modifying the component signals to generate compensated component signals, the means for adaptively modifying compensating for unwanted differences in analog signal paths along which the compensated component signals are amplified; means for amplifying the compensated component signals to generate amplified, compensated component signals; and means for combining the amplified, compensated component signals to generate the output transmission signal. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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Specification