Techniques for Adaptive Predistortion Direct Current Offset Correction in a Transmitter
First Claim
1. An adaptive predistortion unit for a transmitter, comprising:
- an error signal unit having a first input configured to receive a delayed version of a baseband input signal, a second input configured to receive a power amplifier feedback signal from an output of a power amplifier, and an output configured to provide an input error signal that corresponds to a difference between the delayed version of the baseband input signal and the power amplifier feedback signal; and
a signal conditioner having an input configured to receive the input error signal and an output configured to provide an adjusted error signal that has a lower direct current offset than the input error signal.
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Abstract
A technique for performing adaptive predistortion in a transmitter includes receiving, at a first input of an error signal unit, a delayed version of a baseband input signal. The technique also includes receiving, at a second input of the error signal unit, a power amplifier feedback signal from an output of a power amplifier. An input error signal that corresponds to a difference between the delayed version of the baseband input signal and the power amplifier feedback signal is then provided at an output of the error signal unit. The input error signal is then received at an input of a signal conditioner. An adjusted error signal that has a lower direct current offset than the input error signal is provided at an output of the signal conditioner.
51 Citations
20 Claims
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1. An adaptive predistortion unit for a transmitter, comprising:
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an error signal unit having a first input configured to receive a delayed version of a baseband input signal, a second input configured to receive a power amplifier feedback signal from an output of a power amplifier, and an output configured to provide an input error signal that corresponds to a difference between the delayed version of the baseband input signal and the power amplifier feedback signal; and a signal conditioner having an input configured to receive the input error signal and an output configured to provide an adjusted error signal that has a lower direct current offset than the input error signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for performing adaptive predistortion in a transmitter, comprising:
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receiving, at a first input of an error signal unit, a delayed version of a baseband input signal; receiving, at a second input of the error signal unit, a power amplifier feedback signal from an output of a power amplifier; providing, at an output of the error signal unit, an input error signal that corresponds to a difference between the delayed version of the baseband input signal and the power amplifier feedback signal; receiving, at an input of a signal conditioner, the input error signal; and providing, at an output of the signal conditioner, an adjusted error signal that has a lower direct current offset than the input error signal. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A transmitter, comprising:
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a power amplifier; and an adaptive predistortion unit, comprising; an error signal unit having a first input configured to receive a delayed version of a baseband input signal, a second input configured to receive a power amplifier feedback signal from an output of the power amplifier, and an output configured to provide an input error signal that corresponds to a difference between the delayed version of the baseband input signal and the power amplifier feedback signal; and a signal conditioner having an input configured to receive the input error signal and an output configured to provide an adjusted error signal that has a lower direct current offset than the input error signal, wherein lowering the direct current offset associated with the input error signal reduces a transmitted signal distortion associated with the power amplifier. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification