Radio with a distortion compensation capability
First Claim
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1. A radio comprising:
- a power amplifier for amplifying a signal to be transmitted;
a distortion compensator for compensating a distortion of the power amplifier, said distortion compensator havinga distortion compensation coefficient update part for updating distortion compensation coefficients based on a difference between a transmission input signal input to the power amplifier and a feedback signal of a transmission output signal output from the power amplifier,a memory part for storing said distortion compensation coefficients, anda distortion compensation coefficient multiplier for reading out the distortion compensation coefficient from said memory part according to a level of a transmission input signal and multiplying said transmission input signal by said distortion compensation coefficient; and
a bias voltage controller for determining a bias voltage of the power amplifier based on the level of the transmission input signal or a transmit power control signal so as to substantially maximize power efficiency of the power amplifier over a whole operational area thereof while meeting a specification as to an Adjacent Channel Leakage power Ratio (ACLR).
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Abstract
A radio comprises a power amplifier for amplifying a signal to be transmitted; a distortion compensation table storing distortion compensation coefficients for compensating a distortion of the power amplifier; a computing unit for updating the distortion compensation coefficient based on a difference between a transmission input signal and a transmission output signal; a bias voltage controller for applying a bias voltage to the power amplifier, said bias voltage determined based on a transmit control signal so as to maximize a power efficiency of the power amplifier.
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Citations
14 Claims
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1. A radio comprising:
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a power amplifier for amplifying a signal to be transmitted; a distortion compensator for compensating a distortion of the power amplifier, said distortion compensator having a distortion compensation coefficient update part for updating distortion compensation coefficients based on a difference between a transmission input signal input to the power amplifier and a feedback signal of a transmission output signal output from the power amplifier, a memory part for storing said distortion compensation coefficients, and a distortion compensation coefficient multiplier for reading out the distortion compensation coefficient from said memory part according to a level of a transmission input signal and multiplying said transmission input signal by said distortion compensation coefficient; and a bias voltage controller for determining a bias voltage of the power amplifier based on the level of the transmission input signal or a transmit power control signal so as to substantially maximize power efficiency of the power amplifier over a whole operational area thereof while meeting a specification as to an Adjacent Channel Leakage power Ratio (ACLR). - View Dependent Claims (2, 3, 4, 5)
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6. A radio comprising:
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a power amplifier for amplifying a signal to be transmitted; a distortion compensator for compensating a distortion of the power amplifier, said distortion compensator having a distortion compensation coefficient update part for updating distortion compensation coefficients based on a difference between a transmission input signal input to the power amplifier and a feedback signal of a transmission output signal output from the power amplifier, a memory part for storing said distortion compensation coefficients, and a distortion compensation coefficient multiplier for reading out the distortion compensation coefficient from said memory part according to a level of a transmission input signal and multiplying said transmission input signal by said distortion compensation coefficient; a bias voltage controller for determining a bias voltage of the power amplifier based on the level of the transmission input signal or a transmit power control signal so as to improve power efficiency of the power amplifier; a signal divider for dividing a distortion compensated transmission input signal into a transmission input signal and a distortion compensation signal by subtracting the transmission input signal from the distortion compensated transmission input signal; digital-to-analog converters for digital-to-analog converting the transmission input signal and distortion compensation signal separately; and a signal combiner for combining the transmission input signal and the distortion compensation signal to generate the transmission input signal to be input to the power amplifier. - View Dependent Claims (7, 8, 9)
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10. A radio comprising:
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a power amplifier for amplifying a signal to be transmitted; a distortion compensator for compensating a distortion of the power amplifier, said distortion compensator having a distortion compensation coefficient update part for updating distortion compensation coefficients based on a difference between a transmission input signal input to the power amplifier and a feedback signal of a transmission output signal output from the power amplifier, a memory part for storing said distortion compensation coefficients, and a distortion compensation coefficient multiplier for reading out the distortion compensation coefficient from said memory part according to a level of a transmission input signal and multiplying said transmission input signal by said distortion compensation coefficient; and a bias voltage controller for determining a bias voltage of the power amplifier based on the level of the transmission input signal or a transmit power control signal so as to improve power efficiency of the power amplifier, wherein, the distortion compensated transmission input signal is input to the power amplifier via a delay element so that the input of the distortion compensated transmission input signal is timed to the setting of the bias voltage. - View Dependent Claims (11, 12, 13, 14)
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Specification