JPS55133115A - Variable gain amplifying circuit - Google Patents
Variable gain amplifying circuitInfo
- Publication number
- JPS55133115A JPS55133115A JP4043679A JP4043679A JPS55133115A JP S55133115 A JPS55133115 A JP S55133115A JP 4043679 A JP4043679 A JP 4043679A JP 4043679 A JP4043679 A JP 4043679A JP S55133115 A JPS55133115 A JP S55133115A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- output
- transistors
- gain
- changed
- 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
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G1/00—Details of arrangements for controlling amplification
- H03G1/0005—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal
- H03G1/0017—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal the device being at least one of the amplifying solid state elements of the amplifier
- H03G1/0023—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal the device being at least one of the amplifying solid state elements of the amplifier in emitter-coupled or cascode amplifiers
Landscapes
- Control Of Amplification And Gain Control (AREA)
Abstract
PURPOSE:To obtain the gain according to the exponential function of control voltage applied externally, by providing the driver circuit changing the common emitter current of two differential amplifiers in opposite phase each other and operating the difference of each output of the differential amplifiers. CONSTITUTION:The common emitter of the differential amplifiers 22, 23 is connected to the collectors of the transistors 29, 35 of the driver circuit 25, the input signal in voltage Vi of the input terminal 24 is fed to the emitters of the transistors 29, 35 in opposite phase, accordingly the collector voltages V1, V2 of the transistors 28, 33 are changed in opposite phase, and the difference of the both voltages V1, V2 is operated with the subtractor 26 and output. The collector current of the transistors 28, 33 is changed with the voltage Vc fed to the control input terminal 37 and the collector voltage is changed in phase, but it gives no effect to the output. The relation between the output voltage Vo and the gain A of the variable gain amplifying circuit 21 is obtained with equation 22, the gain A is determined with the exponential function of the control voltage Vc, and the circuit 21 can obtain greater S/N at small signal output.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4043679A JPS55133115A (en) | 1979-04-04 | 1979-04-04 | Variable gain amplifying circuit |
| US06/133,990 US4331929A (en) | 1979-04-04 | 1980-03-26 | Gain-controlled amplifier |
| DE19803012965 DE3012965A1 (en) | 1979-04-04 | 1980-04-02 | GAIN-CONTROLLED AMPLIFIER |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4043679A JPS55133115A (en) | 1979-04-04 | 1979-04-04 | Variable gain amplifying circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS55133115A true JPS55133115A (en) | 1980-10-16 |
Family
ID=12580581
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4043679A Pending JPS55133115A (en) | 1979-04-04 | 1979-04-04 | Variable gain amplifying circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS55133115A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5819012A (en) * | 1981-07-25 | 1983-02-03 | Nippon Gakki Seizo Kk | Gain control amplifier |
| JPS5829208A (en) * | 1981-08-14 | 1983-02-21 | Nippon Gakki Seizo Kk | Gain control amplifier |
-
1979
- 1979-04-04 JP JP4043679A patent/JPS55133115A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5819012A (en) * | 1981-07-25 | 1983-02-03 | Nippon Gakki Seizo Kk | Gain control amplifier |
| JPS5829208A (en) * | 1981-08-14 | 1983-02-21 | Nippon Gakki Seizo Kk | Gain control amplifier |
| JPH037161B2 (en) * | 1981-08-14 | 1991-01-31 | Yamaha Corp |
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