| 摘要 |
PROBLEM TO BE SOLVED: To provide a modulation circuit for reducing manufacturing cost corresponding to a modulation system utilizing phase inversion of the RF signal. SOLUTION: The modulation circuit includes: a full-wave rectifier 3 for providing an output after full-wave rectification of a modulation input signal; a comparator 6 for receiving and polarity determining the modulation input signal and providing a determination result after determination of polarity; a polarity switch 7 for receiving a local signal and the determination result and outputting a switched polarity of the local signal on the basis of the determination result; a control current source 5 for generating the current based on an output level of the full-wave rectifier 3; and transistors 4a, 4b constituting a differential pair wherein the emitters are connected to the control current source 5 respectively, and the local signal outputted after switching of the polarity from the polarity switch 7 is applied to the base, and the collector outputs the RF modulation output. COPYRIGHT: (C)2009,JPO&INPIT
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