| 摘要 |
PROBLEM TO BE SOLVED: To provide a high frequency variable gain amplifier capable of extending a dynamic range of received power by switching the gain in multi-stages. SOLUTION: The high frequency variable gain amplifier can switch the gain in three stages: differential amplifiers 50, 51 are set to an operating state and gain changeover switches 30a, 30b are set to a nonconductive state; while the differential amplifier 50 is set to an operation stop state and the differential amplifier 51 is set to the operating state respectively and the gain changeover switches 30a, 30b are set to a conductive state, path switches 31a, 31b of gain switching paths 310a, 310b are set to the conductive state and path switches 32a, 32b of gain switching paths 311a, 311b are set to the nonconductive state; and conversely, the path switches 31a, 31b of the gain switching paths 310a, 310b are set to the nonconductive state and the path switches 32a, 32b of the gain switching paths 311a, 311b are set to the conductive state. COPYRIGHT: (C)2007,JPO&INPIT
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