Predistorter and distortion compensation method
AssigneeFujitsu Limited
InventorsHiroyoshi Ishikawa, Nobukazu Fudaba, Yuichi Utsunomiya, Kazuo Nagatani
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Abstract
A predistorter includes a distortion compensating unit which gives, in advance, a reverse characteristic of a characteristic of input to output of a power amplifier to a transmission signal which is to be input to the power amplifier; a distortion compensation signal generating unit which generates a distortion compensation signal indicating the reverse characteristic based on transmission data that is sample data of the transmission signal and the delayed transmission data; and a delay amount control unit which controls a delay amount of the transmission data according to an output signal of the power amplifier.
Claims13
A predistorter comprising:
- a distortion compensating unit which gives, in advance, a reverse characteristic of a characteristic of input to output of a power amplifier to a transmission signal which is to be input to the power amplifier;
- a measurement control unit that measures one or more adjacent channel leakage power ratios in an output signal of the power amplifier;
- a delay unit which generates delayed transmission data by delaying transmission data that is sample data of the transmission signal by a delay time determined according to the one or more adjacent channel leakage power ratios in the output signal of the power amplifier;
- and
- a distortion compensation signal generating unit which generates a distortion compensation signal indicating the reverse characteristic based on the transmission data and the delayed transmission data,
- wherein the delay unit controls the delay amount of the transmission data according to a difference between an adjacent channel leakage power ratio on a low frequency said and the adjacent channel leakage power ratio on a high frequency side in the output signal of the power amplifier.
A distortion compensation method comprising:
- compensating a distortion of a transmission signal by giving, in advance, a reverse characteristic of a characteristic of input to output of a power amplifier to the transmission signal which is to be input to the power amplifier;
- measuring one or more adjacent channel leakage power ratios in an output signal of the power amplifier;
- generating delayed transmission data by delaying transmission data that is sample data of the transmission signal by a delay time determined according to the one or more adjacent channel leakage power ratios in the output signal of the power amplifier;
- and
- generating a distortion compensation signal indicating the reverse characteristic based on the transmission data and the delayed transmission data,
- wherein the delayed transmission data generating includes controlling the delay amount of the transmission data according to a difference between an adjacent channel leakage power ratio on a low frequency side and the adjacent channel leakage power ratio on a high frequency in the output signal of the power amplifier.
Dependencies are inferred from the claim text.