JP2964516B2 - Automatic gain control amplifier - Google Patents
Automatic gain control amplifierInfo
- Publication number
- JP2964516B2 JP2964516B2 JP1690290A JP1690290A JP2964516B2 JP 2964516 B2 JP2964516 B2 JP 2964516B2 JP 1690290 A JP1690290 A JP 1690290A JP 1690290 A JP1690290 A JP 1690290A JP 2964516 B2 JP2964516 B2 JP 2964516B2
- Authority
- JP
- Japan
- Prior art keywords
- alarm
- circuit
- output
- gain control
- signal
- 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 - Fee Related
Links
Landscapes
- Control Of Amplification And Gain Control (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は自動利得制御増幅器に関し、特に入力信号断
を検知して警報を発する警報手段を有する自動利得制御
増幅器に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic gain control amplifier, and more particularly, to an automatic gain control amplifier having alarm means for detecting an input signal interruption and issuing an alarm.
従来、この種の自動利得制御増幅器は、第２図に一例
を示すように、帯域フィルタ12、可変利得増幅回路１、
検波回路２、利得制御回路３、バイアス電源９、スイッ
チ10を備え、また、入力信号断を検知して警報を発する
ために狭帯域フィルタ４、検波回路５、判定回路６、警
報保持回路７、警報回路８を備えている。Conventionally, this type of automatic gain control amplifier has a bandpass filter 12, a variable gain amplifier circuit 1,
A detection circuit 2, a gain control circuit 3, a bias power supply 9, and a switch 10 are provided. A narrow band filter 4, a detection circuit 5, a judgment circuit 6, an alarm holding circuit 7, An alarm circuit 8 is provided.
入力端子13から入力する入力信号は、隣接信号を除去
するための帯域フィルタ12を経て可変利得増幅回路１へ
入力する。通常は、第１のスイッチ10をＡ側に切替え
て、検波回路２および利得制御回路３からなるAGCルー
プによって可変利得増幅回路１の利得を制御し、一定振
幅の出力信号を出力端子14へ出力させる。また、可変利
得増幅回路１の出力信号の一部を狭帯域フィルタ４を介
して取出して検波回路５で検波し、判定回路６で検波回
路５の検波出力レベルを判定し、もし、所定の検波出力
レベルでないと判定したときは入力信号断を示す警報信
号を生成し、警報保持回路７を介して警報回路８へ送出
する。警報保持回路７は、警報信号が所定の時間継続し
たときに警報信号を警報回路８へ送出する。警報回路８
は警報信号を受けると警報を発する。An input signal input from the input terminal 13 is input to the variable gain amplifying circuit 1 through the bandpass filter 12 for removing an adjacent signal. Normally, the first switch 10 is switched to the A side to control the gain of the variable gain amplifying circuit 1 by an AGC loop composed of the detection circuit 2 and the gain control circuit 3, and to output an output signal having a constant amplitude to the output terminal 14. Let it. Further, a part of the output signal of the variable gain amplifier circuit 1 is extracted through the narrow band filter 4 and detected by the detection circuit 5, and the detection output level of the detection circuit 5 is determined by the determination circuit 6, and if the predetermined detection When it is determined that the input signal is not at the output level, an alarm signal indicating that the input signal has been disconnected is generated and sent to the alarm circuit 8 via the alarm holding circuit 7. The alarm holding circuit 7 sends an alarm signal to the alarm circuit 8 when the alarm signal continues for a predetermined time. Alarm circuit 8
Issues an alarm when it receives an alarm signal.
自動利得制御増幅器の周波数特性等を測定する場合
は、第１のスイッチ10をＢ側に切替えてバイアス電源９
で可変利得増幅回路１の利得を固定した後、入力端子13
に周波数掃引発振器等を接続して出力端子14での出力信
号を測定する。このとき、周波数掃引発振器等によって
信号の周波数が一定の周期で掃引される毎に、出力信号
が狭帯域フィルタ４を介して取出されるので、判定回路
６は断続して警報信号を出力し使用上支障となる。この
ため、警報保持回路７を設けて警報信号を所定の時間保
持する。この場合、警報信号の保持時間を警報信号の断
続する周期ようも長い時間に設定することによって、断
続して警報信号が警報回路８へ送出されないよにし、警
報発動の誤動作を防止している。When measuring the frequency characteristics and the like of the automatic gain control amplifier, the first switch 10 is switched to the B side and the bias power supply 9 is set.
After fixing the gain of the variable gain amplifying circuit 1 with
Is connected to a frequency sweep oscillator or the like, and an output signal at the output terminal 14 is measured. At this time, every time the frequency of the signal is swept by the frequency sweeping oscillator or the like at a fixed cycle, the output signal is taken out through the narrow band filter 4, so that the judgment circuit 6 outputs the alarm signal intermittently and uses it. It will be a hindrance. Therefore, an alarm holding circuit 7 is provided to hold an alarm signal for a predetermined time. In this case, by setting the holding time of the alarm signal to a long period such that the alarm signal is intermittent, the alarm signal is prevented from being intermittently transmitted to the alarm circuit 8, thereby preventing the alarm from malfunctioning.
上述した従来の自動利得制御増幅器では、自動利得制
御増幅器の周波数特性等を周波数掃引発振器等を使用し
て測定する場合に警報回路の誤動作を防止するため、周
波数掃引周期毎に判定回路が断続して出力する警報信号
を警報保持回路によって所定の時間保持させている。こ
のため、通常の使用状態において入力信号断となったと
きの警報回路の動作が遅れるという欠点がある。In the above-described conventional automatic gain control amplifier, when the frequency characteristics and the like of the automatic gain control amplifier are measured using a frequency sweeping oscillator or the like, the determination circuit is intermittently intermittently provided for each frequency sweep period in order to prevent malfunction of the alarm circuit. The alarm signal to be output is held for a predetermined time by an alarm holding circuit. For this reason, there is a disadvantage that the operation of the alarm circuit when the input signal is interrupted in a normal use state is delayed.
本発明の目的は、自動利得制御増幅器の周波数特性等
を測定する場合に警報発動の誤動作を防止すると共に、
通常の使用状態で入力信号断となったときに警報回路が
迅速に動作する自動利得制御増幅器を提供することにあ
る。An object of the present invention is to prevent a malfunction of alarm activation when measuring a frequency characteristic or the like of an automatic gain control amplifier,
An object of the present invention is to provide an automatic gain control amplifier in which an alarm circuit operates quickly when an input signal is interrupted in a normal use state.
〔課題を解決するための手段〕 本発明の自動利得制御増幅器は、利得制御信号に応じ
て利得を制御する可変利得増幅回路と、入力信号断を示
す警報信号を受けると警報を発する警報回路とを有する
自動利得制御増幅器において、前記可変利得増幅回路の
出力信号レベルを検知して前記利得制御信号を生成し出
力する利得制御手段と、前記可変利得増幅回路の利得を
固定するためのバイアス電流を供給するバイアス電源
と、前記可変利得増幅回路の出力側に接続される狭帯域
フィルタと、前記狭帯域フィルタの出力信号レベルを検
知し所定のレベル以下のときに前記警報信号を生成し出
力する警報信号生成手段と、前記警報信号生成手段が出
力する警報信号を所定の時間継続して受けたときに前記
警報信号を送出する警報信号保持手段と、連動して切替
え動作を行う第１および第２のスイッチとを備え、前記
第１のスイッチは、一方の接点に前記利得制御手段の出
力側を接続され、他方の接点に前記バイアス電源を接続
されて切替えに応じていずれかを前記可変利得増幅回路
へ接続し、また、前記第２のスイッチは、一方の接点に
前記警報信号生成手段の出力側を接続され、他方の接点
に前記警報信号保持手段の出力側を接続されて切替えに
応じていずれかを前記警報回路へ接続する構成である。
また、前記第１および第２のスイッチは半導体素子を使
用して構成し、電気的に連動して切替え動作を行うよう
にしてもよい。[Means for Solving the Problems] An automatic gain control amplifier of the present invention includes a variable gain amplifier circuit that controls the gain according to a gain control signal, and an alarm circuit that issues an alarm when receiving an alarm signal indicating that the input signal is disconnected. An automatic gain control amplifier having: a gain control means for detecting an output signal level of the variable gain amplifier circuit to generate and output the gain control signal; and a bias current for fixing a gain of the variable gain amplifier circuit. A bias power supply to be supplied, a narrow band filter connected to the output side of the variable gain amplifier circuit, and an alarm which detects an output signal level of the narrow band filter and generates and outputs the alarm signal when the output signal level is equal to or lower than a predetermined level. Signal generation means, and alarm signal holding means for transmitting the alarm signal when the alarm signal output by the alarm signal generation means is continuously received for a predetermined time; A first switch connected to the output side of the gain control means at one contact, and the bias power supply connected to the other contact. One of the switches is connected to the variable gain amplifier circuit according to the switching, and the second switch has one contact connected to the output side of the alarm signal generating means, and the other contact connected to the alarm signal holding means. Are connected to one another and connected to the alarm circuit in response to switching.
Further, the first and second switches may be configured using a semiconductor element, and may perform a switching operation in an electrically interlocked manner.
次に図面を参照して本発明を説明する。 Next, the present invention will be described with reference to the drawings.
第１図は本発明の一実施例を示す図であり、従来の一
例を示す第２図と比較すると、第２のスイッチ11が付加
されているのが相違している点である。FIG. 1 is a diagram showing an embodiment of the present invention, and is different from FIG. 2 showing an example of the prior art in that a second switch 11 is added.
第１のスイッチ10および第２のスイッチ11は互いに連
動して切替わるスイッチである。通常はＡ側に切替えて
おき、利得制御回路３が出力する利得制御信号を第１の
スイッチ10を介して可変利得増幅回路１へ供給して一定
振幅の出力信号を出力端子14へ送出している。また、可
変利得増幅回路１の出力信号の一部を狭帯域フィルタ４
を介して取出し、検波回路５で検波し、判定回路６は検
波出力レベルを検知し、所定の検波出力レベル以下と判
定したときには入力信号断を示す警報信号を生成し出力
する。この場合、警報信号は警報保持回路７を経由せず
に直接スイッチ11を介して警報回路８へ送出される。The first switch 10 and the second switch 11 are switches that switch in conjunction with each other. Normally, the signal is switched to the A side, the gain control signal output from the gain control circuit 3 is supplied to the variable gain amplifier circuit 1 through the first switch 10, and the output signal having a constant amplitude is sent to the output terminal 14. I have. Further, a part of the output signal of the variable gain amplifier circuit 1 is
The detection circuit 5 detects the detection output level, and when it determines that the detection output level is lower than a predetermined detection output level, generates and outputs an alarm signal indicating that the input signal is disconnected. In this case, the alarm signal is sent to the alarm circuit 8 via the switch 11 directly without passing through the alarm holding circuit 7.
自動利得制御増幅器の周波数特性等を測定する場合
は、第１のスイッチ10および第２のスイッチ11をそれぞ
れＢ側に切替える。この場合は、第１のスイッチ10を介
してバイアス電源９が可変利得増幅回路１へ供給され、
可変利得増幅回路１の利得は固定される。また、第２の
スイッチ11により判定回路６と警報回路８との間に警報
保持回路７が接続される。この状態で、入力端子13に周
波数掃引発振器等を接続して出力端子14での出力信号を
測定する。このとき、一定周期で周波数掃引された出力
信号は狭帯域フィルタ４を介して取出され、判定回路６
はこれを検知して断続して警報信号を出力する。しか
し、第２のスイッチ11によって、判定回路６が出力する
断続した警警報信号は警報保持回路７を介して警報回路
８へ送出されるようになるので、警報発動の誤動作を防
止できる。なお、前記第１および第２のスイッチは半導
体素子を使用して構成し、電気的に連動して切替え動作
を行うものであってもよい。When measuring the frequency characteristics and the like of the automatic gain control amplifier, the first switch 10 and the second switch 11 are each switched to the B side. In this case, the bias power supply 9 is supplied to the variable gain amplifier circuit 1 via the first switch 10,
The gain of the variable gain amplifier circuit 1 is fixed. Further, an alarm holding circuit 7 is connected between the determination circuit 6 and the alarm circuit 8 by the second switch 11. In this state, a frequency sweep oscillator or the like is connected to the input terminal 13 and the output signal at the output terminal 14 is measured. At this time, the output signal whose frequency has been swept at a constant cycle is taken out through the narrow band filter 4 and
Detects this and intermittently outputs an alarm signal. However, the intermittent alarm signal output from the determination circuit 6 is transmitted to the alarm circuit 8 via the alarm holding circuit 7 by the second switch 11, so that malfunction of the alarm can be prevented. Note that the first and second switches may be configured using semiconductor elements, and may perform a switching operation in electrical interlock.
以上説明したように本発明によれば、連動する２つの
スイッチを設け、通常の使用状態の場合は、第１のスイ
ッチでAGCループを形成して可変可変利得増幅回路を動
作させると共に、第２のスイッチで判定回路が出力する
警報信号を直接警報回路へ供給することによって、入力
信号断となったときに警報発動を迅速に行うようにする
ことができる。また、周波数特性等を測定する場合は、
第１のスイッチを切替えて可変利得増幅回路にバイアス
電源を印加して利得を固定すると共に、第２のスイッチ
を切替えて判定回路が出力する警報信号を警報保持回路
７を介して警報回路へ供給することによって、警報発動
の誤動作を防止することができる。As described above, according to the present invention, two interlocked switches are provided, and in a normal use state, the first switch forms an AGC loop to operate the variable variable gain amplifier circuit, and By directly supplying the alarm signal output from the determination circuit to the alarm circuit by the switch, the alarm can be quickly activated when the input signal is interrupted. Also, when measuring frequency characteristics, etc.,
The first switch is switched to apply a bias power to the variable gain amplifier circuit to fix the gain, and the second switch is switched to supply an alarm signal output from the determination circuit to the alarm circuit via the alarm holding circuit 7. By doing so, it is possible to prevent a malfunction in activating the alarm.
第１図は本発明の一実施例を示すブロック図、第２図は
従来の自動利得制御増幅器の一例を示すブロック図であ
る。 １……可変利得増幅回路、２……検波回路、３……利得
制御回路、４……狭帯域フィルタ、５……検波回路、６
……判定回路、７……警報保持回路、８……警報回路、
９……バイアス電源、10……第１のスイッチ、11……第
２のスイッチ、12……帯域フィルタ、13……入力端子、
14……出力端子。FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a conventional automatic gain control amplifier. DESCRIPTION OF SYMBOLS 1 ... Variable gain amplifier circuit, 2 ... Detection circuit, 3 ... Gain control circuit, 4 ... Narrow bandpass filter, 5 ... Detection circuit, 6
... Judgment circuit, 7... Alarm holding circuit, 8.
9 ... bias power supply, 10 ... first switch, 11 ... second switch, 12 ... band-pass filter, 13 ... input terminal,
14 Output terminal.
Claims (2)
利得増幅回路と、入力信号断を示す警報信号を受けると
警報を発する警報回路とを有する自動利得制御増幅器に
おいて、前記可変利得増幅回路の出力信号レベルを検知
して前記利得制御信号を生成し出力する利得制御手段
と、前記可変利得増幅回路の利得を固定するためのバイ
アス電流を供給するバイアス電源と、前記可変利得増幅
回路の出力側に接続される狭帯域フィルタと、前記狭帯
域フィルタの出力信号レベルを検知し所定のレベル以下
のときに前記警報信号を生成し出力する警報信号生成手
段と、前記警報信号生成手段が出力する警報信号を所定
の時間継続して受けたときに前記警報信号を送出する警
報信号保持手段と、連動して切替え動作を行う第１およ
び第２のスイッチとを備え、前記第１のスイッチは、一
方の接点に前記利得制御手段の出力側を接続され、他方
の接点に前記バイアス電源を接続されて切替えに応じて
いずれかを前記可変利得増幅回路へ接続し、また、前記
第２のスイッチは、一方の接点に前記警報信号生成手段
の出力側を接続され、他方の接点に前記警報信号保持手
段の出力側を接続されて切替えに応じていずれかを前記
警報回路へ接続することを特徴とする自動利得制御増幅
器。1. An automatic gain control amplifier comprising: a variable gain amplifier circuit for controlling a gain according to a gain control signal; and an alarm circuit for issuing an alarm when an alarm signal indicating an input signal disconnection is received. Gain control means for detecting an output signal level of the variable gain amplifier to generate and output the gain control signal; a bias power supply for supplying a bias current for fixing the gain of the variable gain amplifier; and an output of the variable gain amplifier. A narrow-band filter connected to the side, an alarm signal generating means for detecting an output signal level of the narrow-band filter and generating and outputting the alarm signal when the output signal level is equal to or lower than a predetermined level, and output by the alarm signal generating means Alarm signal holding means for transmitting the alarm signal when the alarm signal is continuously received for a predetermined time; first and second switches for performing a switching operation in conjunction with the alarm signal holding means; The first switch has one contact connected to the output side of the gain control means, the other contact connected to the bias power supply, and connected to the variable gain amplifier circuit according to switching. The second switch has one contact connected to the output side of the alarm signal generating means, and the other contact connected to the output side of the alarm signal holding means, and switches one of the switches in response to switching. An automatic gain control amplifier connected to an alarm circuit.
子を使用して構成され電気的に連動して切替え動作を行
うことを特徴とする請求項１記載の自動利得制御増幅
器。2. The automatic gain control amplifier according to claim 1, wherein said first and second switches are constituted by using semiconductor elements and perform a switching operation in an electrically interlocked manner.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1690290A JP2964516B2 (en) | 1990-01-25 | 1990-01-25 | Automatic gain control amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1690290A JP2964516B2 (en) | 1990-01-25 | 1990-01-25 | Automatic gain control amplifier |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03220809A JPH03220809A (en) | 1991-09-30 |
| JP2964516B2 true JP2964516B2 (en) | 1999-10-18 |
Family
ID=11929076
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1690290A Expired - Fee Related JP2964516B2 (en) | 1990-01-25 | 1990-01-25 | Automatic gain control amplifier |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2964516B2 (en) |
-
1990
- 1990-01-25 JP JP1690290A patent/JP2964516B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03220809A (en) | 1991-09-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |