| 摘要 |
Existing modems of time division duplex (TDD) type can be utilized without modification to perform a high speed wireless communication with stable communication quality in other frequency bands such as quasi-millimeter to millimeter wave bands. There are included a circulator ( 11 ) connected to TDD modems ( 1, 2 ) and receives signals transmitted thereby to output those signals from a first connection terminal (p 1 ) and outputs signals received at a second connection terminal (p 2 ) to the TDD modems ( 1, 2 ), and a frequency converter ( 2 a) that raise the frequency of the signals from the circulator ( 11 ) by a predetermined frequency width and lowers the frequency of signals from a receive antenna ( 32 ) by a predetermined frequency width. It may be arranged that the frequency conversion width be made different between the uplink and downlink and that a filter, which blocks the transmitting wireless frequency and passes the receiving wireless frequency, is provided between the receive antenna ( 32 ) and a frequency converter ( 22 a).
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