| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of switches to be switched in response to transmission reception. SOLUTION: A 90 deg. hybrid 9 distributes an output SIF of a modulator 6 to provide signals SIF1 , SIF2 (the latter is led more than the former byπ/2) to frequency converters 1, 2 respectively in the case of transmission and the signals are mixed with the output of a local oscillator 11 to obtain signals SRF1 , SRF2 and they are fed to a 90 deg. hybrid 8. Two signals at an upper side band f1 =fL+f1 corresponding to them are strengthened to each other in phase at a terminal 15 and the result is sent as a signal SRF. Two signals at the lower side band f2 =fL-f1 are cancelled in the opposite phases and not transmitted. In the case of reception, a hybrid 8 provides signals SRF1 , SIF2 . (the latter is led more than the former byπ/2) to the frequency converters 1, 2 respectively and the signals are mixed with the output of a local oscillator 11 to obtain signals SIF1 , SIF2 and they are fed to the 90 deg. hybrid 9. Two signals at an upper side band are strengthened to each other in phase at a terminal 13 and the result is given to a demodulator. Two signals at the lower side band are cancelled in the opposite phases.
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