JPS6258168B2 - - Google Patents
Info
- Publication number
- JPS6258168B2 JPS6258168B2 JP8459279A JP8459279A JPS6258168B2 JP S6258168 B2 JPS6258168 B2 JP S6258168B2 JP 8459279 A JP8459279 A JP 8459279A JP 8459279 A JP8459279 A JP 8459279A JP S6258168 B2 JPS6258168 B2 JP S6258168B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- amplitude
- amplifier
- output
- input
- 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.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/3005—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Control Of Amplification And Gain Control (AREA)
Description
【発明の詳細な説明】
この発明は、入力信号を一定振幅の信号とする
ように増幅する受信機等の自動利得制御回路に関
する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic gain control circuit for a receiver or the like that amplifies an input signal so as to have a constant amplitude.
従来、この種の自動利得制御回路は、入力信号
を増幅した後、検波等によりその振幅の平均的な
値の直流信号をフイード・バツクさせることによ
り、入力信号を一定振幅とするように制御してい
た。しかし、従来の回路は、その回路を構成する
要素の温度特性により、回路の利得特性も変化し
てしまい、入力信号を一定振幅とする制御が十分
に得られない欠点があつた。 Conventionally, this type of automatic gain control circuit controls the input signal to have a constant amplitude by amplifying the input signal and then feeding back a DC signal with an average amplitude value using detection or the like. was. However, conventional circuits have the disadvantage that the gain characteristics of the circuit change depending on the temperature characteristics of the elements constituting the circuit, making it difficult to control the input signal to a constant amplitude.
この発明は、上記のような従来のものの欠点を
除去するためになされたもので、入力信号の振幅
を一定となるように増幅することができる自動利
得制御回路を提供することを目的とする。 The present invention was made in order to eliminate the drawbacks of the conventional ones as described above, and an object of the present invention is to provide an automatic gain control circuit that can amplify the amplitude of an input signal to a constant value.
以下、本発明の一実施例を図について説明す
る。図において、入力信号Ａは、振幅信号ａを有
し、asinωｔで表わされる交流信号で、減算器１
及び振幅検出回路２に入力される。減算器１に
は、次に述べるようにフイード・バツク信号KaB
も入力されており、これより入力信号Ａからフイ
ード・バツク信号KaBを減算した信号（Ａ−
KaB）が出力される。信号（Ａ−KaB）は、十分
に大きな値の利得Ｇを有する増幅器３に入力さ
れ、これより信号Ｂが出力される。信号Ｂは、振
幅検出回路２より出力される信号ａと共に掛算器
４に入力される。掛算器４は、信号ａと信号Ｂと
を掛算した信号aBを出力し、これを利得Ｋの増
幅器５に入力する。これにより、増幅器５は信号
KaBを減算器１に入力する。 Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In the figure, the input signal A is an alternating current signal having an amplitude signal a and represented by asinωt.
and is input to the amplitude detection circuit 2. Subtractor 1 receives a feed back signal KaB as described below.
is also input, and the signal obtained by subtracting the feed back signal KaB from input signal A (A-
KaB) is output. The signal (A-KaB) is input to an amplifier 3 having a sufficiently large gain G, from which signal B is output. Signal B is input to multiplier 4 together with signal a output from amplitude detection circuit 2 . The multiplier 4 multiplies the signal a and the signal B to output a signal aB, which is input to the amplifier 5 with a gain of K. This causes the amplifier 5 to
Input KaB to subtractor 1.
いま、増幅器３の信号Ｂに着目すると、次式が
成立する。 Now, focusing on the signal B of the amplifier 3, the following equation holds true.
（Ａ−KaB）Ｇ＝Ｂ …(1)
(1)式を変形すると、
Ａ−KaB＝Ｂ／Ｇ …(2)
利得Ｇは十分に大きな値であるから、(2)式から
Ａ＝KaB …(3)
を得る。従つて、(3)式は、
Ｂ＝１／Ｋ Ａ／ａ …(4)
となる。そして、Ａ＝ａ sin ωｔであるか
ら、これを(4)式に代入すると、
Ｂ＝１／Ｋsin ωｔ …(5)
となる。(5)式から明らかなように、信号Ｂは、入
力信号Ａの振幅ａに無関係な値を有するものとな
り、その振幅が１／Ｋで一定の値となる。つまり、図
示の回路は、入力信号Ａの振幅ａが変化しても一
定の振幅１／Ｋを有する信号Ｂを出力するように動作
する。 (A-KaB)G=B...(1) Transforming equation (1), A-KaB=B/G...(2) Since the gain G is a sufficiently large value, from equation (2), A=KaB …(3) is obtained. Therefore, equation (3) becomes: B=1/K A/a (4). Since A=a sin ωt, substituting this into equation (4) yields B=1/Ksin ωt (5). As is clear from equation (5), signal B has a value that is independent of the amplitude a of input signal A, and its amplitude is a constant value of 1/K. That is, the illustrated circuit operates so as to output a signal B having a constant amplitude 1/K even if the amplitude a of the input signal A changes.
以上のように、本発明によれば、出力される信
号と入力信号の振幅値の信号を掛け合せ、一定の
利得で増幅し、十分大きな利得を有する増幅器に
ネガテイブ・フイードバツクすることにより、入
力信号を高い安定度をもつて一定振幅の信号に増
幅することができる。 As described above, according to the present invention, the input signal is multiplied by the amplitude value of the output signal and the input signal, amplified with a constant gain, and negatively fed back to an amplifier having a sufficiently large gain. It is possible to amplify the signal to a constant amplitude signal with high stability.
図は本発明の一実施例を示すブロツク図であ
る。
２……振幅検出器、３，５……増幅器、４……
掛算器。
The figure is a block diagram showing one embodiment of the present invention. 2...Amplitude detector, 3, 5...Amplifier, 4...
Multiplier.
Claims (1)
振幅信号を出力する振幅検出回路と、前記振幅信
号と最終的に出力される出力信号とを掛け合せる
掛算器と、前記掛算器の信号を一定の利得で増幅
する第１の増幅器と、入力信号を前記第１の増幅
器から出力される信号で減算する減算器と、前記
減算器から出力される信号を実質的に無限大の利
得で増幅する第２の増幅器とを有する自動利得制
御回路。1. An amplitude detection circuit that detects the amplitude of an input signal and outputs an amplitude signal proportional to the amplitude, a multiplier that multiplies the amplitude signal by an output signal that is finally output, and a multiplier that keeps the signal of the multiplier constant. a first amplifier that amplifies with a gain of , a subtracter that subtracts an input signal by a signal output from the first amplifier, and amplifies the signal output from the subtracter with a gain of substantially infinity. an automatic gain control circuit having a second amplifier;
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8459279A JPS567507A (en) | 1979-07-02 | 1979-07-02 | Automatic gain control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8459279A JPS567507A (en) | 1979-07-02 | 1979-07-02 | Automatic gain control circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS567507A JPS567507A (en) | 1981-01-26 |
| JPS6258168B2 true JPS6258168B2 (en) | 1987-12-04 |
Family
ID=13834941
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8459279A Granted JPS567507A (en) | 1979-07-02 | 1979-07-02 | Automatic gain control circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS567507A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5977747U (en) * | 1982-11-17 | 1984-05-25 | 株式会社東海理化電機製作所 | pressure switch |
-
1979
- 1979-07-02 JP JP8459279A patent/JPS567507A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS567507A (en) | 1981-01-26 |
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