| 摘要 |
PROBLEM TO BE SOLVED: To provide a duplexer, using no filter, which is essential to realize mixed type frequency allocation by eliminating band division and a communication system whose speed is increased by short-time frames although a conventional duplexer uses a filter and is adaptive to a communication system wherein "up" and "down" bands are sectioned. SOLUTION: Disclosed is the duplexer characterized in that two transformers are used, coils driven by amplifiers of the respective transformers are connected in serial, and current negative feedback is provided from the connection point. Further, the duplexer is characterized in that a communication line is connected to another coil of an amplifier direct-connection side transformer, a voltage comparators compares voltages of detection coils of the two transformers, and a signal of their difference is regarded as a receive signal. COPYRIGHT: (C)2005,JPO&NCIPI
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