Fast adaptive wideband power amplifier feed forward linearizer using a RLS parameter tracking algorithm
First Claim
1. A feedforward linearizer for amplifying an input signal comprises:
- a signal cancellation circuit having a first signal cancellation branch and a second signal cancellation branch;
a first amplifier provided in said first signal cancellation branch, said amplifier configured to receive said input signal intended to be amplified;
a signal cancellation vector modulator coupled to said first amplifier, and configured to receive an output signal provided by said first amplifier;
a signal cancellation adder coupled to said signal cancellation vector modulator and configured to receive the signal generated by said signal cancellation vector modulator, said signal cancellation adder configured to receive said input signal via said second signal cancellation branch and to provide an error signal;
an error cancellation circuit having a first error cancellation branch and a second error cancellation branch;
an error cancellation adder in said first error cancellation branch, said error cancellation adder configured to receive the output signal provided by said first amplifier, the output of said error cancellation adder provide the output signal of said linearizer;
an error cancellation vector modulator in said second error cancellation branch, configured to receive said error signal provided by said signal cancellation adder and provide an error adjusted signal;
a second auxiliary amplifier coupled to said error cancellation vector modulator configured to provide an input signal to said error cancellation adder; and
a digital signal processor configured to provide a signal cancellation adjustment signal, α
, to said signal cancellation vector modulator and an error cancellation adjustment signal, β
, to said error cancellation vector modulator respectively, such that the output signal of said signal cancellation adder is a signal that substantially represents the error components provided by said first amplifier, and the output signal of the error cancellation adder is an amplified version of the input signal, with substantially no intermodulation components.
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Accused Products
Abstract
A feedforward linearizer for amplifying an input signal comprises a signal cancellation circuit which has a first branch and a second branch. A first amplifier provided in the first branch receives the input signal intended to be amplified and generates an output signal received by a signal cancellation vector modulator. A signal cancellation adder receives the signal generated by the signal cancellation vector modulator and the input signal via the second branch and provides an error signal. The feedforward linearizer also comprises an error cancellation circuit that has a first branch and a second branch. An error cancellation adder in the first branch receives the output signal provided by the first amplifier and generates the output signal of the linearizer. An error cancellation vector modulator in the second branch receives an error signal provided by the signal cancellation adder and provides an error adjusted signal to a second auxiliary amplifier. The second auxiliary amplifier provides an input signal to the error cancellation adder. A digital signal processor provides a signal cancellation adjustment signal, α, to the signal cancellation vector modulator and an error cancellation adjustment signal, β, to the error cancellation vector modulator respectively, such that the output signal of the signal cancellation adder is a signal that substantially represents the error components provided by the first amplifier, and the output signal of the error cancellation adder is an amplified version of the input signal, with substantially no internmodulation components.
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Citations
17 Claims
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1. A feedforward linearizer for amplifying an input signal comprises:
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a signal cancellation circuit having a first signal cancellation branch and a second signal cancellation branch; a first amplifier provided in said first signal cancellation branch, said amplifier configured to receive said input signal intended to be amplified; a signal cancellation vector modulator coupled to said first amplifier, and configured to receive an output signal provided by said first amplifier; a signal cancellation adder coupled to said signal cancellation vector modulator and configured to receive the signal generated by said signal cancellation vector modulator, said signal cancellation adder configured to receive said input signal via said second signal cancellation branch and to provide an error signal; an error cancellation circuit having a first error cancellation branch and a second error cancellation branch; an error cancellation adder in said first error cancellation branch, said error cancellation adder configured to receive the output signal provided by said first amplifier, the output of said error cancellation adder provide the output signal of said linearizer; an error cancellation vector modulator in said second error cancellation branch, configured to receive said error signal provided by said signal cancellation adder and provide an error adjusted signal; a second auxiliary amplifier coupled to said error cancellation vector modulator configured to provide an input signal to said error cancellation adder; and a digital signal processor configured to provide a signal cancellation adjustment signal, α
, to said signal cancellation vector modulator and an error cancellation adjustment signal, β
, to said error cancellation vector modulator respectively, such that the output signal of said signal cancellation adder is a signal that substantially represents the error components provided by said first amplifier, and the output signal of the error cancellation adder is an amplified version of the input signal, with substantially no intermodulation components. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. In a feedforward linearizer a method for linearizing an amplifier by deriving an error signal corresponding to distortions deemed generated by said amplifier, and applying an adjusted version of said error signal to the output signal of said amplifier so as to provide a substantially error free amplified version of said output signal, said method comprising the steps of:
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(a) calculating a set of coefficients corresponding to a mathematical model of said amplifier; (b) calculating a set of correlation values, ρ
ij, between the input signal and said output signal of said amplifier;(c) calculating a signal cancellation adjustment signal based on said calculated coefficients and said calculated correlation values; (d) applying said calculated signal cancellation adjustment signal to said output signal of said amplifier so as to derive an adjusted output signal of said amplifier; and (e) calculating a difference between said adjusted output signal and said input signal so as to derive said error signal. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification