Invention Grant
- Patent Title: Variable gain amplifier circuit and filter circuit
- Patent Title (中): 可变增益放大器电路和滤波电路
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Application No.: US12691480Application Date: 2010-01-21
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Publication No.: US08111096B2Publication Date: 2012-02-07
- Inventor: Kazuaki Oishi
- Applicant: Kazuaki Oishi
- Applicant Address: JP Kawasaki
- Assignee: Fujitsu Limited
- Current Assignee: Fujitsu Limited
- Current Assignee Address: JP Kawasaki
- Agency: Murphy & King P.C.
- Priority: JP2007-036165 20070216
- Main IPC: H03K5/00
- IPC: H03K5/00
Abstract:
This variable gain amplifier is provided with an operational amplifier. The non-inversion input terminal of the operational amplifier is connected to a reference potential. A feedback resistor is connected between the output terminal and inversion input terminal of the operational amplifier. An input resistor is inserted between the inversion input terminal of the operational amplifier and the input terminal of the variable gain amplifier circuit. An adjustment resistor is connected between the inversion input terminal of the operational amplifier and the reference potential. The resistance value of the adjustment resistor is controlled in such a way as to maintain constant against the resistance value change a combined resistance value in its parallel connection with the input resistor when changing the resistance value of the input resistor.
Public/Granted literature
- US20100171549A1 Variable Gain Amplifier Circuit and Filter Circuit Public/Granted day:2010-07-08
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