Telecommunications – Transmitter – With feedback of modulated output signal
Patent
1996-03-18
1999-05-11
Mullen, Jr., Thomas J.
Telecommunications
Transmitter
With feedback of modulated output signal
330149, 375297, H01Q11/12
Patent
active
059038233
ABSTRACT:
Disclosed is a radio apparatus in which modulating signals (I and 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 of carrier produced due 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 of carrier (offset) becomes zero.
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Moriyama Yukihiro
Ohsaki Yoshiya
Fujitsu Limited
Mullen Jr. Thomas J.
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