Circuit and method for compensating for non-linear distortion
First Claim
1. A method for compensating for non-linear distortion generated during non-linear high-power amplification in a transmitter after quadrature modulation, the transmitter having a distortion extractor for extracting a non-linear distortion component from a non-linearly high-power amplified modulated signal, a quadrature modulator for quadrature modulating the non-linear distortion component into a baseband distortion component after phase adjustment, and a distortion overlapping section for overlapping the baseband signal with a phase-inverted distortion component of the baseband distortion component, the method comprising the steps of:
- attenuating an output signal of the high-power amplifier by a gain of the high-power amplifier when the high-power amplifier generates an amplified signal, and extracting a non-linear distortion component by subtracting a phase-adjusted input signal of the high-power amplifier from the attenuated output signal; and
converting the non-linear distortion component into a DC (Direct Current) component, and automatically controlling an attenuation of the output signal of the high-power amplifier to minimize the DC component.
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Accused Products
Abstract
An apparatus for compensating for non-linear distortion generated during non-linear high-power amplification in a transmitter for non-linearly high-power amplifying a baseband signal by a high-power amplifier after quadrature modulation having a distortion extractor for extracting a non-linear distortion component from the non-linearly high-power amplified modulated signal. A quadrature modulator quadrature-modulates the non-linear distortion component into a baseband distortion component after phase adjustment. A distortion overlapping section overlaps the baseband signal with a phase-inverted distortion component of the baseband distortion component. A converter converts the non-linear distortion component output from the distortion extractor into a DC component. A controller automatically controls an attenuation of the output signal of the high-power amplifier to minimize the DC component output from the converter.
25 Citations
6 Claims
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1. A method for compensating for non-linear distortion generated during non-linear high-power amplification in a transmitter after quadrature modulation, the transmitter having a distortion extractor for extracting a non-linear distortion component from a non-linearly high-power amplified modulated signal, a quadrature modulator for quadrature modulating the non-linear distortion component into a baseband distortion component after phase adjustment, and a distortion overlapping section for overlapping the baseband signal with a phase-inverted distortion component of the baseband distortion component, the method comprising the steps of:
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attenuating an output signal of the high-power amplifier by a gain of the high-power amplifier when the high-power amplifier generates an amplified signal, and extracting a non-linear distortion component by subtracting a phase-adjusted input signal of the high-power amplifier from the attenuated output signal; and
converting the non-linear distortion component into a DC (Direct Current) component, and automatically controlling an attenuation of the output signal of the high-power amplifier to minimize the DC component.
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2. An apparatus for compensating for non-linear distortion generated during non-linear high-power amplification in a transmitter after quadrature modulation, the transmitter having a distortion extractor for extracting a non-linear distortion component from a non-linearly high-power amplified modulated signal, a quadrature modulator for quadrature modulating the non-linear distortion component into a baseband distortion component after phase adjustment, and a distortion overlapping section for overlapping the baseband signal with a phase-inverted distortion component of the baseband distortion component, the apparatus comprising:
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a converter for converting the non-linear distortion component output from the distortion extractor into a DC component; and
a controller for automatically controlling an attenuation of the output signal of the high-power amplifier to minimize the DC component output from the converter. - View Dependent Claims (3)
an attenuator for attenuating the output signal of the high-power amplifier by a gain equal to the gain of the high-power amplifier, when the high-power amplifier outputs an amplified signal;
a phase shifter for shifting a phase of an input signal of the high-power amplifier; and
a subtracter for subtracting an output signal of the phase shifter from an output signal of the attenuator;
wherein the attenuator, under the control of the controller, automatically controls an attenuation of the output signal of the high-power amplifier to minimize the DC component output from the converter.
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4. A method for compensating for non-linear distortion generated during non-linear high-power amplification in a transmitter after quadrature modulation, the transmitter having a distortion extractor for extracting a non-linear distortion component from a non-linearly high-power amplified modulated signal, a quadrature modulator for quadrature modulating the non-linear distortion component into a baseband distortion component after phase adjustment, and a distortion overlapping section for overlapping the baseband signal with a phase-inverted distortion component of the baseband distortion component, the method comprising the step of:
suspending an operation of overlapping the baseband signal with a phase-inverted distortion component of the baseband distortion component, when an input power level of the high-power amplifier drops below a power level at a point where an input power-to-ACPR characteristic of the high-power amplifier becomes worse during non-linear distortion compensation control than during suspension of the non-linear distortion compensation control.
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5. An apparatus for compensating for non-linear distortion generated during non-linear high-power amplification in a transmitter after quadrature modulation, the transmitter having a distortion extractor for extracting a non-linear distortion component from a non-linearly high-power amplified modulated signal, a quadrature modulator for quadrature modulating the non-linear distortion component into a baseband distortion component after phase adjustment, and a distortion overlapping section for overlapping the baseband signal with a phase-inverted distortion component of the baseband distortion component, the apparatus comprising:
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a switch for switching a signal input into said distortion overlapping section, said signal included in a feedback loop formed between the distortion extractor and the distortion overlapping section;
a power detector for detecting an input power level of the high-power amplifier;
a controller for receiving the signal detected by the power detector and turning OFF the switch when the input power level of the high-power amplifier drops below a power level at a point where an input power-to-ACPR characteristic of the high-power amplifier becomes worse during non-linear distortion compensation control than during suspension of the non-linear distortion compensation control.
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6. An apparatus for compensating for non-linear distortion generated during non-linear high-power amplification in a transmitter after quadrature modulation, the transmitter having a distortion extractor for extracting a non-linear distortion component from a non-linearly high-power amplified modulated signal, a quadrature modulator for quadrature modulating the non-linear distortion component into a baseband distortion component after phase adjustment, and a distortion overlapping section for overlapping the baseband signal with a phase-inverted distortion component of the baseband distortion component, the apparatus comprising:
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a power detector for detecting an input power level of the high-power amplifier; and
a controller for receiving the signal detected by the power detector and disabling one of a plurality of function elements included in a feedback loop formed between the distortion extractor and the distortion overlapping section, when the input power level of the high-power amplifier drops below a power level at a point where an input power-to-ACPR characteristic of the high-power amplifier becomes worse during non-linear distortion compensation control than during suspension of the non-linear distortion compensation control.
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Specification