Digitally implemented predistorter control mechanism for linearizing high efficiency RF power amplifiers
First Claim
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1. An RF power amplifier apparatus comprising:
- an RF input port to which an RF input signal is applied;
an RF output port from which an amplified RF output signal is derived;
an RF power amplifier coupled between said RF input port and said RF output port and being operative to amplify an RF signal applied thereto so as to produce said amplified RF output signal;
an RF predistortion unit coupled to a signal path for said RF input signal and being controllably operative to adjust the RF input signal applied to said RF power amplifier; and
a digital signal processor (DSP), which is operative to execute a first signal processing operator in terms of a digital polynomial-based predistortion function that approximates an inverse of the dynamic memory effects in the nonlinear transfer characteristic of said RF power amplifier, said digital polynomial-based predistortion function being used to control said RF predistortion unit in a manner that predistorts said RF input signal to compensate for said dynamic memory effects of the nonlinear transfer characteristic of said RF power amplifier.
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Abstract
A digitally-based high distortion rejection scheme for linearizing an RF power amplifier employs a digital signal processor, which executes a first signal processing operator in terms of a digital polynomial-based predistortion function that approximates an inverse of the dynamic memory effects in the nonlinear transfer characteristic of the amplifier, and a second signal processing operator that represents an inverse of static non-linearities in the transfer characteristic of the amplifier. The output of this cascaded filter operation is used to control parameters of a vector modulator in the signal input path to the RF power amplifier. The vector modulator thus predistorts the RF input signal, so as to compensate for dynamic memory effects and static non-linearities in the power amplifier.
118 Citations
20 Claims
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1. An RF power amplifier apparatus comprising:
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an RF input port to which an RF input signal is applied;
an RF output port from which an amplified RF output signal is derived;
an RF power amplifier coupled between said RF input port and said RF output port and being operative to amplify an RF signal applied thereto so as to produce said amplified RF output signal;
an RF predistortion unit coupled to a signal path for said RF input signal and being controllably operative to adjust the RF input signal applied to said RF power amplifier; and
a digital signal processor (DSP), which is operative to execute a first signal processing operator in terms of a digital polynomial-based predistortion function that approximates an inverse of the dynamic memory effects in the nonlinear transfer characteristic of said RF power amplifier, said digital polynomial-based predistortion function being used to control said RF predistortion unit in a manner that predistorts said RF input signal to compensate for said dynamic memory effects of the nonlinear transfer characteristic of said RF power amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of reducing the effects of intermodulation distortion of an RF power amplifier comprising the steps of:
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(a) coupling an RF input signal to be amplified by said RF power amplifier to an RF predistortion unit that is controllably operative to adjust the RF input signal applied to said RF power amplifier;
(b) generating predistortion model that approximates an inverse of the transfer characteristic of said RF power amplifier, including a first signal processing operator that compensates for static non-linearities, and a second polynomial-based signal processing operator that compensates for dynamic memory effects in the amplifier'"'"'s non-linear transfer characteristic; and
(c) controlling said RF predistortion unit in accordance with said first and second signal processing operators so as to predistort said RF input signal and compensate for distortion effects of said RF power amplifier. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 19, 20)
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18. An RF power amplifier apparatus comprising:
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an RF power amplifier coupled between an RF input port and an RF output port and being operative to amplify an RF signal applied thereto so as to produce an amplified RF output signal;
a vector modulator coupled to receive said RF input signal and being controllably operative to adjust the RF input signal applied to said RF power amplifier; and
a digital signal processor (DSP), which is programmed to execute a first signal processing operator in terms of a digital polynomial-based predistortion function that approximates an inverse of dynamic memory effects in the nonlinear transfer characteristic of said RF power amplifier, said digital polynomial-based predistortion function being used to control said vector modulator in a manner that predistorts said RF input signal to compensate for said dynamic memory effects of the nonlinear transfer characteristic of said RF power amplifier.
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Specification
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Current AssigneeREMEC, Inc.
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Original AssigneeSpectrian Corp. (REMEC, Inc.)
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InventorsCova, Armando C.
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Application NumberUS09/954,088Publication NumberTime in Patent OfficeDaysField of SearchUS Class Current330/149CPC Class CodesH03F 1/3247 using feedback acting on pr...H03F 1/3258 based on polynomial termsH03F 1/3282 Acting on the phase and the...
