| 摘要 |
A radio telephone apparatus of the TDMA/TDD system includes a frequency division orthogonal modulator (111) including a frequency divider (210) for dividing by four a local signal having a frequency which is four times that of the intermediate frequency to obtain a carrier having a frequency shifted from that of the local signal by 90 DEG . The signal to be modulated is subjected to an orthogonal modulation in mixers (203A, 203B) according to the carrier wave to produce an intermediate frequency carrier. The operation of the modulator is stopped in a signal reception state by a signal at a power down terminal (209) to prevent the intermediate frequency carrier from being produced. Signal transmission and reception are conducted using carriers having different frequencies. By these measures cochannel interference from the transmitter entering the receiver in the same housing is reduced. <IMAGE> |
