Radio apparatus
First Claim
1. A radio apparatus for subjecting a modulating signal to pre-distortion processing using distortion compensation coefficients which correct distortion of a transmission power amplifier, amplifying, by the transmission power amplifier, a carrier wave obtained by being digitally modulated by the modulating signal that has been subjected to the pre-distortion processing, transmitting the amplified carrier wave, comparing the modulating signal with a demodulated signal, which is obtained by branching and demodulating the transmitted carrier, and updating the distortion compensation coefficients, said apparatus comprising:
- phase-difference measuring means for measuring, prior to pre-distortion processing, a phase difference between a demodulated signal and a modulating signal, wherein the demodulated signal is obtained by detecting a carrier wave that is the result of digital modulation by the modulating signal having a fixed phase and amplitude; and
phase-difference correcting means for executing phase-difference correction processing in such a manner that the phase difference becomes zero.
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Accused Products
Abstract
Disclosed is a radio apparatus in which modulating signals (I, Q signals) from an arithmetic/control unit are converted to analog signals, which are then applied to an orthogonal modulator. A modulated wave for transmission, which has been produced by orthogonally modulating a reference carrier wave by the modulating signals, is demodulated by the orthogonal detector. The arithmetic/control unit compares the modulating signals and the demodulated signals and, based upon the comparison, updates distortion compensation coefficients and applies pre-distortion processing to the modulating signal using the distortion compensation coefficients. Leakage carrier produced due to offset of the orthogonal modulator is detected and the arithmetic/control unit adjusts the level of the modulating signals or shifts the phase of the reference carrier wave in such a manner that the leakage carrier (offset) becomes zero.
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Citations
7 Claims
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1. A radio apparatus for subjecting a modulating signal to pre-distortion processing using distortion compensation coefficients which correct distortion of a transmission power amplifier, amplifying, by the transmission power amplifier, a carrier wave obtained by being digitally modulated by the modulating signal that has been subjected to the pre-distortion processing, transmitting the amplified carrier wave, comparing the modulating signal with a demodulated signal, which is obtained by branching and demodulating the transmitted carrier, and updating the distortion compensation coefficients, said apparatus comprising:
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phase-difference measuring means for measuring, prior to pre-distortion processing, a phase difference between a demodulated signal and a modulating signal, wherein the demodulated signal is obtained by detecting a carrier wave that is the result of digital modulation by the modulating signal having a fixed phase and amplitude; and phase-difference correcting means for executing phase-difference correction processing in such a manner that the phase difference becomes zero. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification