Method and apparatus for adjusting modulation accuracy of an orthogonal modulation

摘要

A method of adjusting modulation accuracy corrects an I modulation signal and a Q modulation signal without using special hardware when an accurate 90 DEG phase difference between the I modulation signal and the Q modulation signal is not present. The method comprises setting I component correction DELTA i for a plurality of phase differences in advance to an I component corrector in accordance with an I signal, which is converted from digital modulation data in a digital data train by a modulator and an IQ converter of a phase error corrector. The method also comprises setting a Q component correction DELTA q for a plurality of phase differences in advance to a Q component corrector in accordance with a Q signal, controlling the I component corrector and the Q component corrector by a phase error correction controller, thereby adding the I component correction DELTA i and the Q component correction DELTA q to the I signal and the Q signal so as to generate a corrected I signal and a corrected Q signal. Thus the phase difference between an I modulation signal and a Q modulation signal is accurately adjusted to 90 DEG .