| 摘要 |
PROBLEM TO BE SOLVED: To provide the radio transmitter-receiver in which the effect of operation of a transmitter is reduced during the reception operation. SOLUTION: An oscillated frequency fLO of an oscillation circuit 5 is frequency-divided by frequency dividers 12, 13 and fed to mixers 2, 10. A frequency division ratio of the frequency divider 13 of a receiver is selected to be N1 . Furthermore, the frequency divider 12 of a transmitter has a frequency division ratio of N1 or N2 (N1≠N2 ) that is selected by a frequency divider switching signal. In the case of the operation of the receiver, the frequency division ratio N2 of the frequency divider 12 is selected and a frequency fLO/N2 is given to the mixer 2 of the transmitter and a frequency fLO/N1 is given to the mixer 10 of the receiver. In the case of the operation of the transmitter, the frequency division ratio of the frequency divider 12 is selected to be N1 and a frequency fLO/N1 is given to the mixer 2.
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