QPSK TRANSMITTER, QPSK RECEIVER, QPSK TRANSMISSION SYSTEM AND FSK RECEIVER

摘要

PROBLEM TO BE SOLVED: To simplify the QPSK transmission system while coping with disturbance of a channel by reserving two channels for transmission signals. ;SOLUTION: A QPSK transmitter 10 applies DSB transmission to a QPSK modulation signal. A QPSK receiver 40 applies QPSK demodulation to an upper side band or a lower side band of the DSB transmission signal from the QPSK transmitter 10. An IQ changeover section 54 connects an I axis output terminal 44 and a Q axis output terminal 46 to an I input terminal 50 and a Q input terminal 52 of a PCM decoder 48 respectively while a QPSK demodulation section 42 applies QPSK demodulation to the upper side band, and connects the Q axis output terminal 46 and the I axis output terminal 44 to the I input terminal 50 and the Q input terminal 52 of the PCM decoder 48 respectively while the QPSK demodulation section 42 applies QPSK demodulation to the lower side band.;COPYRIGHT: (C)1998,JPO