JPH0969740A - Automatic gain control circuit - Google Patents
Automatic gain control circuitInfo
- Publication number
- JPH0969740A JPH0969740A JP22350495A JP22350495A JPH0969740A JP H0969740 A JPH0969740 A JP H0969740A JP 22350495 A JP22350495 A JP 22350495A JP 22350495 A JP22350495 A JP 22350495A JP H0969740 A JPH0969740 A JP H0969740A
- Authority
- JP
- Japan
- Prior art keywords
- output
- gain control
- transient response
- level
- 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.)
- Withdrawn
Links
Landscapes
- Control Of Amplification And Gain Control (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Noise Elimination (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】一般の無線通信機の復調処理
に用いる信号パワーは、受信精度などの観点から極力一
定(所望の値)であることが望ましい。一方、通信相手
局が複数ある場合、相手局により通信距離や伝搬経路が
異なり、従って受信信号レベル(パワー)も自ずと異な
る。BACKGROUND OF THE INVENTION It is desirable that the signal power used for demodulation processing of a general wireless communication device is as constant as possible (desired value) from the viewpoint of reception accuracy and the like. On the other hand, when there are a plurality of communication partner stations, the communication distance and the propagation path differ depending on the partner stations, and therefore the received signal level (power) also naturally differs.
【0002】この発明は受信信号レベルに応じて増幅利
得を制御し、安定した復調処理を実現するための自動利
得制御回路に関する。The present invention relates to an automatic gain control circuit for controlling an amplification gain according to a received signal level and realizing stable demodulation processing.
【0003】[0003]
【従来の技術】図3に従来の自動利得制御回路の例を簡
略に示す。入力端子11からの入力信号は可変利得増幅
器12により、利得制御信号に比例した利得で増幅され
て出力端子13に出力されると共に、レベル検出器14
へ供給される。レベル検出器14で検出された出力信号
レベルPO と端子15より目標値(レベル)PS との差
が差分検出器16で検出され、この差分(制御偏差量)
がループフィルタ17に入力される。このループフィル
タ17の出力は、利得制御信号として可変利得増幅器1
2に入力され、その出力レベルが一定(=目標レベル)
となるように閉ループが形成している。入力端子11の
入力信号の有無がキャリアセンス18で検出され、その
検出出力で入力信号を検出している状態で可変利得増幅
器12の利得を制御する動作状態に入力信号を検出しな
い状態で初期化状態にループフィルタ17が制御され
る。2. Description of the Related Art FIG. 3 schematically shows an example of a conventional automatic gain control circuit. The input signal from the input terminal 11 is amplified by the variable gain amplifier 12 with a gain proportional to the gain control signal and output to the output terminal 13, and the level detector 14
Supplied to The difference between the output signal level P O detected by the level detector 14 and the target value (level) P S from the terminal 15 is detected by the difference detector 16, and this difference (control deviation amount) is detected.
Is input to the loop filter 17. The output of the loop filter 17 is used as a gain control signal for the variable gain amplifier 1
Input to 2 and its output level is constant (= target level)
A closed loop is formed so that The presence / absence of an input signal at the input terminal 11 is detected by the carrier sense 18, and the input signal is detected by the detection output and initialized to an operating state in which the gain of the variable gain amplifier 12 is controlled while the input signal is not detected. The loop filter 17 is controlled to the state.
【0004】入力信号を検出している動作状態で可変利
得増幅器12の利得Aは、 A=KA ・GC (1) KA :利得定数〔1/パワー〕 GC :利得制御信号レベル〔パワー〕 で表される。従って入力信号のレベルPI に対する出力
レベルPO は、 PO =KA ・GC ・PI (2) となる。一方、前述した通り、受信(入力)信号レベル
PI は相手局(送信元)により異なるが、個々の通信に
おいては、受信信号レベルPI は一定値として扱うこと
ができる。従って、利得制御信号レベルGC を入力信号
(変数)としたときの可変利得増幅器12の開ループ伝
達関数は、 KA ・PI (3) となる。(KA ,PI は共に定数) 図4は以上の点に鑑み、従来の自動利得制御回路により
形成される閉ループについて、扱う物理量(信号)を信
号のレベル(パワー)で統一し、目標値(PS)から制
御量(PI )までを伝達関数ブロックでモデル化したも
のである。即ち出力レベルPO と目標値PS との差が差
回路16でとられ、その差出力が伝達関数F(s) のルー
プフィルタ17に供給され、その出力が入力信号PI を
利得KA倍する回路12を通じて出力信号を得る。従っ
て、この閉ループの伝達関数は、 (KA ・PI ・F(s))/(1+KA ・PI ・F(s)) (4) となる。In the operating state in which the input signal is detected, the gain A of the variable gain amplifier 12 is A = K A · G C (1) K A : gain constant [1 / power] G C : gain control signal level [ Power]. Therefore, the output level P O with respect to the level P I of the input signal is P O = K A · G C · P I (2) On the other hand, as described above, the reception (input) signal level P I differs depending on the partner station (transmission source), but the reception signal level P I can be treated as a constant value in each communication. Therefore, the open loop transfer function of the variable gain amplifier 12 when the gain control signal level G C is the input signal (variable) is K A · P I (3). (K A and P I are both constants) In view of the above points, FIG. 4 shows that the closed loop formed by the conventional automatic gain control circuit unifies the physical quantity (signal) to be handled with the signal level (power), and sets the target value. (P S ) to the controlled variable (P I ) are modeled by a transfer function block. That is, the difference between the output level P O and the target value P S is taken in the difference circuit 16, the difference output is supplied to the loop filter 17 of the transfer function F (s), and the output thereof is obtained by inputting the input signal P I to the gain K A. The output signal is obtained through the multiplying circuit 12. Therefore, the transfer function of this closed loop is (K A · P I · F (s)) / (1 + K A · P I · F (s)) (4).
【0005】受信信号の無い状態から信号受信状態へ移
ったとき(フィルタが初期化状態から動作状態に移った
とき)の閉ループ系の過渡応答は、仮想的に、目標値に
単位ステップを入力することで知ることができる。この
閉ループのステップ応答は式(4)より、 P0(s)=KA ・PI ・F(s) /((1+KA ・PI ・F(s) )・S) P0(t)=L-1{KA ・PI ・F(s) /((1+KA ・PI ・F(s))・S)} となる。For the transient response of the closed loop system when the state where there is no received signal is changed to the state where the signal is received (when the filter is changed from the initializing state to the operating state), the unit step is virtually input to the target value. You can know it. From the equation (4), the step response of this closed loop is P 0 (s) = K A · P I · F (s) / ((1 + K A · P I · F (s)) · S) P 0 (t) = L −1 {K A · P I · F (s) / ((1 + K A · P I · F (s)) · S)}.
【0006】一定以上の受信精度を得るためには、式
(5)から導かれる過渡応答が、ある一定の誤差範囲内
に収束していなければならない。従って、過渡応答が収
束するまでの間は所望の受信精度が得られないので、送
信機はダミーデータを送出する必要がある。式(5)よ
り、P0(t)はPI の関数となり、一般に、PI が小さい
ほど一定の誤差範囲内に収束するのに要する時間は長
く、また、PI が大きいほど閉ループ系は不安定とな
る。In order to obtain a reception accuracy above a certain level, the transient response derived from the equation (5) must converge within a certain error range. Therefore, the desired reception accuracy cannot be obtained until the transient response converges, and the transmitter must send dummy data. From Equation (5), P 0 (t) is a function of P I , and generally, the smaller P I is, the longer it takes to converge within a certain error range, and the larger P I is, the closed loop system becomes. Becomes unstable.
【0007】従来は、設計上の最大受信入力があった場
合でも閉ループ系が安定するようにF(s) を決定し、次
に設計上の最小受信入力があった場合の過渡応答を評価
し、ダミーデータの長さ(送出時間)を決定していた。Conventionally, F (s) is determined so that the closed loop system is stable even if there is the maximum designed input, and then the transient response when the designed minimum received input is present is evaluated. , The length of dummy data (transmission time) was determined.
【0008】[0008]
【発明が解決しようとする課題】以上述べたように、従
来の自動利得制御回路では、閉ループ系の過渡応答は受
信信号レベルPI の関数となるため、系の過渡応答特性
や安定性からF(s) を一元に決定できない。つまり、受
信信号レベルによって最適なF(s) が異なる。この発明
は、過渡応答が受信信号レベルPI により左右されない
閉ループ系を構成し、過渡応答特性や安定性の優れた自
動利得制御回路を提供することを目的とする。As described above, in the conventional automatic gain control circuit, since the transient response of the closed loop system is a function of the received signal level P I , the transient response characteristic and stability of the system cause F Unable to determine (s) in a unified way. That is, the optimum F (s) differs depending on the received signal level. An object of the present invention is to provide an automatic gain control circuit which forms a closed loop system in which a transient response is not influenced by the received signal level P I and which is excellent in transient response characteristics and stability.
【0009】[0009]
【課題を解決するための手段】この発明は、従来の自動
利得制御回路の構成に加え、入力信号の実効値を知るた
めの第2のレベル検出器を設け、その第2のレベル検出
器の出力でループフィルタの出力を除算する除算器を設
け、この除算器の出力で可変利得増幅器の利得を制御す
る。According to the present invention, in addition to the structure of a conventional automatic gain control circuit, a second level detector for knowing the effective value of an input signal is provided. A divider that divides the output of the loop filter by the output is provided, and the output of the divider controls the gain of the variable gain amplifier.
【0010】この構成により過渡応答が受信信号レベル
PI により左右されない自動利得制御回路が実現され
る。With this configuration, an automatic gain control circuit whose transient response is not influenced by the received signal level P I is realized.
【0011】[0011]
【発明の実施の形態】図1にこの発明の実施例を示し、
図3と対応する部分に同一符号を付けてある。この発明
においては、入力端子11よりの入力受信信号はレベル
検出器21にも分岐供給され、受信信号の実効値が検出
される。また、ループフィルタ17の出力側と可変利得
増幅器12の制御入力側との間に除算器22が挿入さ
れ、除算器22でループフィルタ17の出力がレベル検
出器21の検出出力で除算され、その除算結果が利得制
御信号として可変利得増幅器12へ供給される。FIG. 1 shows an embodiment of the present invention.
Parts corresponding to those in FIG. 3 are denoted by the same reference numerals. In the present invention, the input reception signal from the input terminal 11 is also branched and supplied to the level detector 21, and the effective value of the reception signal is detected. Further, a divider 22 is inserted between the output side of the loop filter 17 and the control input side of the variable gain amplifier 12, and the output of the loop filter 17 is divided by the detected output of the level detector 21 in the divider 22. The division result is supplied to the variable gain amplifier 12 as a gain control signal.
【0012】この場合の制御閉ループを伝達関数ブロッ
クでモデル化すると図2に示すように、図3に対し、目
標値PS と出力レベルPO との差に対して、F(s)o, K
A ,PI をそれぞれ乗算した値を入力レベルPI で除算
し、その除算結果を出力POとする構成となる。この閉
ループのステップ応答は以下のようになる。When the control closed loop in this case is modeled by a transfer function block, as shown in FIG. 2, the difference between the target value P S and the output level P O is F (s) o, K
A value obtained by multiplying A and P I is divided by the input level P I , and the result of the division is used as the output P O. The step response of this closed loop is as follows.
【0013】 PO (s) =(KA ・PI ・(1/PI )・F(s))/{(1+KA ・PI ・ (1/PI )・F(s))・S} =(KA ・F(s))/((1+KA ・F(s))・S) PO (t) =L-1{KA ・F(s) /((1+KA ・F(s) ・S))} 以上より、この発明の自動利得制御回路の場合、閉ルー
プ系の過渡応答は、受信信号レベルPI とは無関係とな
る。従って、過渡応答特性や安定性の立場から最適なF
(s) を決定でき、その結果、従来と比べ安定性が高く、
過渡応答も良好な利得制御を行うことができ、従って必
要なダミーデータが短くて済むため、効率の良い通信が
行える。P O (s) = (K A · P I · (1 / P I ) · F (s)) / {(1 + K A · P I · (1 / P I ) · F (s)) · S} = (K A · F (s)) / ((1 + K A · F (s)) · S) P O (t) = L −1 {K A · F (s) / ((1 + K A · F (s) .S))} From the above, in the case of the automatic gain control circuit of the present invention, the transient response of the closed loop system becomes independent of the received signal level P I. Therefore, from the standpoint of transient response characteristics and stability, the optimum F
(s) can be determined, and as a result, stability is higher than before,
Gain control can also be performed well in the transient response, and therefore the required dummy data can be short, so efficient communication can be performed.
【0014】[0014]
【発明の効果】以上述べたように、この発明による自動
利得制御回路の過渡応答は、受信信号レベルPI とは無
関係であり、過渡応答特性や安定性の立場から最適なF
(s) を決定でき、従来の構成と比べ、相対的に安定性が
高く、必要なダミーデータの短い(効率の良い通信が行
える)自動利得制御回路が実現できる。As described above, the transient response of the automatic gain control circuit according to the present invention is irrelevant to the received signal level P I, and is optimum for the transient response characteristic and stability.
It is possible to determine (s), and it is possible to realize an automatic gain control circuit that has relatively high stability as compared with the conventional configuration and has a short required dummy data (allows efficient communication).
【図1】この発明による自動利得制御回路の一実施例を
示すブロック図。FIG. 1 is a block diagram showing an embodiment of an automatic gain control circuit according to the present invention.
【図2】図1に示した自動利得制御回路の伝達関数ブロ
ック。FIG. 2 is a transfer function block of the automatic gain control circuit shown in FIG.
【図3】従来の自動利得制御回路を示すブロック図。FIG. 3 is a block diagram showing a conventional automatic gain control circuit.
【図4】図3に示した自動利得制御回路の伝達関数ブロ
ック。4 is a transfer function block of the automatic gain control circuit shown in FIG.
Claims (1)
の増幅出力信号のレベルがレベル検出器で検出され、そ
の検出レベルと目標値との差が差検出手段で検出され、
その差検出出力がループフィルタに供給され、そのルー
プフィルタの出力である利得制御信号により、上記可変
利得増幅器の利得が、上記差検出手段の出力がゼロにな
るように制御され、入力信号の有無が入力検出手段で検
出され、その検出が得られないとその出力で上記ループ
フィルタが初期状態に制御される自動利得制御回路にお
いて、 上記入力信号の実効値を検出する第2レベル検出器と、 その第2レベル検出器の検出出力で上記ループフィルタ
の出力を除算して、上記可変利得増幅器へ利得制御信号
として供給する除算手段と、 を有することを特徴とする自動利得制御回路。1. An input signal is amplified by a variable gain amplifier, the level of the amplified output signal is detected by a level detector, and the difference between the detected level and a target value is detected by difference detection means,
The difference detection output is supplied to the loop filter, the gain control signal which is the output of the loop filter controls the gain of the variable gain amplifier so that the output of the difference detection means becomes zero, and the presence or absence of the input signal. Is detected by the input detection means, and when the detection is not obtained, the loop filter is controlled to the initial state by its output, in the automatic gain control circuit, a second level detector for detecting the effective value of the input signal, An automatic gain control circuit, comprising: a division unit that divides the output of the loop filter by the detection output of the second level detector and supplies the output to the variable gain amplifier as a gain control signal.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP22350495A JPH0969740A (en) | 1995-08-31 | 1995-08-31 | Automatic gain control circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP22350495A JPH0969740A (en) | 1995-08-31 | 1995-08-31 | Automatic gain control circuit |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0969740A true JPH0969740A (en) | 1997-03-11 |
Family
ID=16799188
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP22350495A Withdrawn JPH0969740A (en) | 1995-08-31 | 1995-08-31 | Automatic gain control circuit |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0969740A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100462727C (en) * | 2004-02-24 | 2009-02-18 | 博计电子股份有限公司 | Simulator of AC electronic load suitable to any waveform of AC signal |
-
1995
- 1995-08-31 JP JP22350495A patent/JPH0969740A/en not_active Withdrawn
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100462727C (en) * | 2004-02-24 | 2009-02-18 | 博计电子股份有限公司 | Simulator of AC electronic load suitable to any waveform of AC signal |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20021105 |