| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic gain control circuit and an automatic gain control system capable of coping with received signals of various radio wave forms and signal forms. SOLUTION: The automatic gain control circuit is provided with a variable gain amplifier and ensures the dynamic range of a received signal capable of being processed by a unit such as an A/D converter connected to the post-stage of the amplifier by controlling its amplifier gain. Further, the automatic gain control circuit detects the peak level and the carrier level of the received signal, selects a level which is higher than the other level, and compares the selected level with a reference level that is based on an input full scale value or the like of the A/D converter. When the control of the amplifier gain is required, the automatic gain control circuit generates a gain control signal on the basis of the selected level from the peak level or the carrier level, and applies the control signal to the variable gain amplifier to cope with the received signals of the various radio wave forms and signal forms. COPYRIGHT: (C)2006,JPO&NCIPI
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