| 摘要 |
PROBLEM TO BE SOLVED: To reduce the leakage of locally oscillated signals into modulated output signals at digital radio communication equipment for which the phase modulating system ofπ/4 shift QPSK is mainly utilized. SOLUTION: Concerning this equipment, a digital signal processing part 2 is equipped with a signal generating part 2a for detection with which I and Q signals are generated out during the period of an idle time slot for detecting the level of locally oscillated signals to be leaked into the output of a quadrature modulation part 7, and the equipment is provided with a detection part 12 and an A/D converting part 14 for feeding detection data indicating the leakage level of locally oscillated signals back to the digital signal processing part 2 based on an output signal S1 from the quadrature modulation part. Then, based on the fed-back detection data, the digital signal processing part 2 outputs origin voltage correction data while including them in the I and Q signals and by correcting an origin voltage related to the outputs of respective amplifiers for these I and Q signals with these origin voltage correction data, the level of locally oscillated signals to be leaked into the outputs of the quadrature modulation part 7 is minimized.
|
