JPS5496345A - Variable gain amplifier - Google Patents
Variable gain amplifierInfo
- Publication number
- JPS5496345A JPS5496345A JP274178A JP274178A JPS5496345A JP S5496345 A JPS5496345 A JP S5496345A JP 274178 A JP274178 A JP 274178A JP 274178 A JP274178 A JP 274178A JP S5496345 A JPS5496345 A JP S5496345A
- Authority
- JP
- Japan
- Prior art keywords
- input
- circuit
- signal
- constant current
- gain control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
PURPOSE: To avoid the output fluctuation and occurrence of distortion even to the excessive input by constituting the emitter current source of the emitter-earthed amplifier circuit with the constant current circuit and then varying the current of the constant current circuit with the gain control signal.
CONSTITUTION: The points of difference are as follws. Constant current circuit 14 comprising transistor Tr15 and bias resistance R16 is provided, along with R17 and 18 (the other side of R17 earthed directly) to give a constant bias. Gain control input terminal 11 is connected to the base of Tr15 in circuit 14 to control the constant current level of circuit 14 with the gain control signal. Accordingly, capacitor 19 is charged with the current which flows forward through the base-emitter junction of Tr1 at the positive peak level of the signal of input 4 even in case the input signal of input terminal 4 increases in the strong electric field, and thus kept at the positive peak level of the signal of input 4. Thus, Tr1 always holds the breaking state to the input signal of over a certain level, causing no fluctuation of the modulation degree nor the distortion.
COPYRIGHT: (C)1979,JPO&Japio
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP274178A JPS5496345A (en) | 1978-01-17 | 1978-01-17 | Variable gain amplifier |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP274178A JPS5496345A (en) | 1978-01-17 | 1978-01-17 | Variable gain amplifier |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS5496345A true JPS5496345A (en) | 1979-07-30 |
Family
ID=11537763
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP274178A Pending JPS5496345A (en) | 1978-01-17 | 1978-01-17 | Variable gain amplifier |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5496345A (en) |
-
1978
- 1978-01-17 JP JP274178A patent/JPS5496345A/en active Pending
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