| 摘要 |
PROBLEM TO BE SOLVED: To reduce a gain at a ferromagnetic field and suppress distortion generated in an amplifying transistor. SOLUTION: The variable gain amplifier comprises an amplifying transistor 21 for inputting a signal to a base and outputting the amplified signal from a collector and a pin diode 27 for negative feedback inserted between the base and collector of the amplifying transistor 21. A base bias voltage of the amplifying transistor 21 and a current of the pin-diode 27 for negative feedback are changed by an AGC voltage, and the current of the pin-diode 27 is increased and the base bias voltage is increased accompanied by the increment of the input signal. COPYRIGHT: (C)2007,JPO&INPIT
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