JPS58197906A - Amplifier circuit for switching gain - Google Patents
Amplifier circuit for switching gainInfo
- Publication number
- JPS58197906A JPS58197906A JP8188582A JP8188582A JPS58197906A JP S58197906 A JPS58197906 A JP S58197906A JP 8188582 A JP8188582 A JP 8188582A JP 8188582 A JP8188582 A JP 8188582A JP S58197906 A JPS58197906 A JP S58197906A
- Authority
- JP
- Japan
- Prior art keywords
- differential amplifier
- switching
- amplifier
- gain
- 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.)
- 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
- H03G1/0088—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal using discontinuously variable devices, e.g. switch-operated
Landscapes
- Control Of Amplification And Gain Control (AREA)
Abstract
Description
【発明の詳細な説明】
この発明は利得切換え増幅回路に関し、特に、磁気記録
再生装置において、記録、＃１１１００利得切換えおよ
び色信号、バースト信号に対する利得切換えに適した増
幅器に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gain switching amplifier circuit, and more particularly to an amplifier suitable for recording, #11100 gain switching, and gain switching for color signals and burst signals in a magnetic recording/reproducing device.
ＮＴＳＣ方式におけるＶＨ８方式の磁気記録再生装置で
は、記録時にカラーバースト信号を２倍にして記録し、
逆に再生時にそのバースト信号を１、−’ ２倍にして
再生している。このため従来の記録、再生共用可能な色
信号処理回路の入力端では、記録時と再生時および色信
号時とバースト信号時の信号レベルの違いを一致させる
ため、種々の利得の興なる増幅回路が必要であった。し
かし、この場合種々の利得の興なる各増幅回路は、たと
えば個別の定電流源が接続されており、その出力１流電
圧レベルが変動するという問題があった。In the VH8 format magnetic recording and reproducing device in the NTSC format, the color burst signal is doubled and recorded.
Conversely, during reproduction, the burst signal is multiplied by 1, -'2 and reproduced. For this reason, at the input end of a conventional color signal processing circuit that can be used for both recording and reproduction, amplification circuits with various gains are used to match the differences in signal levels during recording and reproduction, and between color signals and burst signals. was necessary. However, in this case, each amplifier circuit with various gains is connected to, for example, an individual constant current source, and there is a problem in that the output voltage level of the single current source fluctuates.
それゆえに、この発明の主たる目的は前記欠点を解消し
た利得切換え増幅回路を提供することである。Therefore, the main object of the present invention is to provide a gain switching amplifier circuit which eliminates the above-mentioned drawbacks.
この発明は、簡単に言うならば、入力信号に応じて、電
源により付勢される共通の負荷から共通の定電流源へ電
流を流して、負荷電圧を出力として取出す増幅器ｔあっ
て、共通の負荷と共通の定電流源の圀に、共通の負荷に
共通的に接続される３つの差動増幅器と、信号に応じて
その３つの増幅器のうち１つを選択してオンするスイッ
チング［ｉ、１．、□え、い、□。え□□、あ７７、
！さらに詳しく言えば、スイッチング回路を構成する
切換えスイッチング素子の入力電極を予め異なった直流
電圧でプルアップしておき、高い電圧にプルアップされ
た１〜ランジスタから順にオンしていく切換え方式の利
得切換え増幅回路である。To put it simply, this invention includes an amplifier t which flows a current from a common load energized by a power supply to a common constant current source in response to an input signal and extracts the load voltage as an output. Three differential amplifiers commonly connected to the common load are connected to a constant current source common to the load, and a switching device [i, 1. , □Eh, I, □. E□□、A77、
! More specifically, gain switching is a switching method in which the input electrodes of the switching elements that make up the switching circuit are pulled up in advance with different DC voltages, and the transistors 1 to 1 are turned on in order, starting with the transistors that have been pulled up to a higher voltage. It is an amplifier circuit.
この発明のその他の目的と特徴は以下の図面を参照して
行なう詳細な説明から一層明らかとなろう。Other objects and features of the invention will become more apparent from the detailed description given below with reference to the drawings.
図はこの発明の一実施例である磁気記録再生装置の色信
号処理回路における利得切換え増幅回路の回路図である
。図を参照してまずこの回路の構成を説明する。The figure is a circuit diagram of a gain switching amplification circuit in a color signal processing circuit of a magnetic recording/reproducing apparatus which is an embodiment of the present invention. First, the configuration of this circuit will be explained with reference to the drawing.
差動増幅器１１，１２．１３は同一定格の１対のトラン
ジスタと抵抗１４．１５または１６で構成されている。The differential amplifiers 11, 12, 13 are composed of a pair of transistors of the same rating and a resistor 14, 15 or 16.
そして、差動増幅器の出力端子である１対のトランジス
タのコレクタ端子はそれぞれ共通的に共通の負荷抵抗１
０または共通のり一層２５を介して電源１により付勢さ
れている。この共通の負荷抵抗１０．共通のリード２５
が共通負荷を構成しており、出力端子７にこの負荷抵抗
１０とリード２５の差の電圧が出力される。The collector terminals of the pair of transistors, which are the output terminals of the differential amplifier, are connected to a common load resistance 1.
0 or energized by the power supply 1 via the common glue layer 25. This common load resistance 10. common lead 25
constitutes a common load, and the voltage difference between this load resistor 10 and the lead 25 is output to the output terminal 7.
差動増幅器１１．１２のトランジスタベースには記録信
号入力端子２から記録信号が入力し、差動増幅器１３の
トランジスタベース端子には再生信号入力端子ｉから再
生信号が入力する。そしてこれらの出力は、当然のこと
ながら、出力端子７に出力される。A recording signal is input from the recording signal input terminal 2 to the transistor bases of the differential amplifiers 11 and 12, and a reproduction signal is input from the reproduction signal input terminal i to the transistor base terminal of the differential amplifier 13. These outputs are naturally output to the output terminal 7.
差動増幅回路１１．１２．１３Ｌｔスイッチング回路に
接続されるが、それは次のような構成になっている。ま
ず、差動増幅器１１．１２．１３はＮＰＮトランジスタ
１８，１９．２０のそれぞれのコレクタに接続され、そ
れら各トランジスタのエミッタは共通の定電流１１２４
に接続されている。Differential amplifier circuits 11, 12, and 13 are connected to the Lt switching circuit, which has the following configuration. First, the differential amplifiers 11, 12, 13 are connected to the respective collectors of NPN transistors 18, 19, 20, and the emitters of each of these transistors are connected to a common constant current 1124.
It is connected to the.
前記各トランジスタ１Ｂ、１９．２０のそれぞれのベー
ス端子は、端子４，５．３からそれぞれ異なる直流電圧
によってプルアップされている。この場合の直流電圧は
、端子４〉端子５〉端子３、の順に印加電圧の大きさが
定められている。そしてさらに、トランジスタ１８のベ
ース端子は色信号、バースト信号利得切換え制御信号に
よってオンまたはオフするエミッタ接地ＮＰＮトランジ
スタ２２に接続されており、トランジスタ２０のベース
端子は記録、再生切換え制御信号によってオンまたはオ
フするエミッタ接地Ｎ Ｐ Ｎ ＋・ランジスタ２３に
接続され＝（いる。The respective base terminals of the transistors 1B, 19.20 are pulled up by different DC voltages from the terminals 4, 5.3. In this case, the magnitude of the DC voltage applied is determined in the order of terminal 4>terminal 5>terminal 3. Further, the base terminal of the transistor 18 is connected to a common emitter NPN transistor 22 which is turned on or off by a color signal or burst signal gain switching control signal, and the base terminal of the transistor 20 is turned on or off by a recording or reproduction switching control signal. The emitter is connected to the grounded N P N + transistor 23.
また、前述のように、記録信号入力端一７２に記録信号
が加えられ、再１信号入力端子８に再生信号が加えられ
、出力端子７から回路出力が得られる。Ｄｉｎ抵抗１０
の共通な差動ｌＮ６１１！１１．１２゜１３はそれぞれ
相対的に利得が興なり、差動！１幅器］２は差動増幅Ｗ
ＩＴより６ｄＢ利得が高い関係にある。また差動増幅Ｂ
１３の利得は再生に最も適する利得に選ばれる。Further, as described above, a recording signal is applied to the recording signal input terminal 72, a reproduction signal is applied to the second signal input terminal 8, and a circuit output is obtained from the output terminal 7. Din resistance 10
The common differential lN611!11.12°13 has a relative gain, and the differential! 1 width amplifier] 2 is differential amplification W
The relationship is that the gain is 6 dB higher than that of IT. Also, differential amplification B
A gain of 13 is selected as the gain most suitable for reproduction.
次に、この回路の動作を説明する。再生時には、記録、
再生切換え制御端子９がローレベル（０゜７〜′以下）
となり、この場合色信号、バースト信号利得切換え制御
−子６の状態の如何にかかわらず、トランジスタ２０が
オンし、トランジスタ１８．１９はオフして定電流源２
４は差動増幅器１３に接続され、差動増幅器１３が動作
する。Next, the operation of this circuit will be explained. During playback, recording,
Regeneration switching control terminal 9 is at low level (below 0°7~')
In this case, regardless of the state of the color signal and burst signal gain switching control element 6, the transistor 20 is turned on, and the transistors 18 and 19 are turned off, so that the constant current source 2
4 is connected to the differential amplifier 13, and the differential amplifier 13 operates.
次に、記録時には、記録、再生切換え制御信号入力端子
９に接続されている記録中であることを示す信号がハイ
レベル（０，７Ｖ以上）となるため、トランジスタ２３
がオンしトランジスタ２゜のベース電圧がほぼＯｖにな
る。そうすると、トランジスタ２０はオフし、ついで＾
い直流電圧のかかつているトランジスタ１８がオンする
。そして、定電流源２４は差動増幅器１１に接続されこ
れが動作する。このとき、色信号、バースト信号利得切
換え制御信号入力端子６に入力される色信号、バースト
信号利得切換え制御信号は、バースト信号区間以外の区
間を表わすローレベルである。Next, during recording, the signal connected to the recording/playback switching control signal input terminal 9 indicating that recording is in progress becomes high level (0.7 V or more), so the transistor 23
turns on, and the base voltage of transistor 2° becomes approximately Ov. Then, the transistor 20 turns off, and then ^
The transistor 18 to which a high DC voltage is applied is turned on. The constant current source 24 is connected to the differential amplifier 11 and operates. At this time, the chrominance signal and the burst signal gain switching control signal input to the chrominance signal and burst signal gain switching control signal input terminal 6 are at a low level representing a section other than the burst signal section.
そして、バースト信号区間にはこの端子６に入力される
色信号、バースト信号利得切換え制御信号はバースト区
間を表わすハイレベルになるためトランジスタ２２がオ
ン、トランジスタ１８のベース電位がほぼＯｖになって
、トランジスタ１８はオフする。よって最後のトランジ
スタ１９がオンすることとなる。すなわちこれは、定電
流Ｉ［２４が差動増幅器１１よりも６ｄＢ利得の高い差
動増幅器１２に接続されたことを意味する。During the burst signal period, the color signal input to this terminal 6 and the burst signal gain switching control signal are at a high level representing the burst period, so the transistor 22 is turned on and the base potential of the transistor 18 becomes approximately Ov. Transistor 18 is turned off. Therefore, the last transistor 19 is turned on. That is, this means that the constant current I[24 is connected to the differential amplifier 12 whose gain is 6 dB higher than that of the differential amplifier 11.
以上のように、この発明によれば、３つの差動増幅器の
出力端子にｈＩ統する負荷を共通にし、共通端子に接Ｌ
ｌｌる定電流源を単一定′４流澱としてこれを切換えて
、ｆｋｌ！録、再生の切換えおよｔＪ’ｆｆｉ信号とパ
ース！−信号の利得切換えを行なっているため、信号切
換え時、１なわち各差動増幅器の切換え時ににおいで、
出力は号の直流動作点が変動しないという効ｉｔ有（る
。これはプなわら、この回路の次に接＠する増幅器の動
作点を常に一定にすることができ動作点変動による波形
歪、出力変動をも防ぐことができることを意味する。As described above, according to the present invention, the output terminals of the three differential amplifiers have a common load connected to the hI, and the common terminal is connected to the load L.
Switching the constant current source to a single constant current source, fkl! Recording/playback switching and tJ'ffi signal and parsing! -Since the signal gain is switched, there is an odor when switching the signal, that is, when switching each differential amplifier.
It has the advantage that the DC operating point of the output signal does not fluctuate.This also means that the operating point of the amplifier connected next to this circuit can always be kept constant, which eliminates waveform distortion due to operating point fluctuations. This means that output fluctuations can also be prevented.
図はこの発明の一実施例である磁気記録再生装習の色信
号処理回路における利得切換え増幅ｎ路の回路図である
、
図において、２は記録信号人カニ４？！、３，４゜５は
直流電圧入力端子、６は色信号、バースト４８号利得切
換え制御１１ｆｉ号入力端子、７ ｉｔ出出端端子８は
再生信号人力瑞子、９は配録、再生切換え制御信り入力
端子、１１．１２．１３は利得の異なる差動増幅器、１
８．１９．２０．２２．２３はＮＰＮトランジスタ、２
４は定電流源、１０は共通の負荷抵抗、２５は共通のリ
ードを示す。The figure is a circuit diagram of an n-path gain switching amplification circuit in a color signal processing circuit for magnetic recording and reproducing equipment, which is an embodiment of the present invention. ! , 3,4゜5 is a DC voltage input terminal, 6 is a color signal, burst No. 48 gain switching control 11fi No. input terminal, 7 it output terminal 8 is a reproduction signal human power Zuiko, 9 is a distribution, reproduction switching control signal 11.12.13 are differential amplifiers with different gains, 1
8.19.20.22.23 is NPN transistor, 2
4 is a constant current source, 10 is a common load resistance, and 25 is a common lead.
Claims (6)
の負荷から共通の定電流源へ電流を流して、負荷電圧を
出力として取出す増幅器であって、共通の負荷と、 その共通の負荷に共通的に接続される相対的に利得の興
なる第１．第２および第３の差動増幅器と、 前記差動増′幅器に接続されその差動増幅器の中から入
力信号に応答して１つを選択的に有効化するスイッチン
グ回路と、そのスイッチング回路に接続される共通の単
一定電ｓｍｍとを備えていることを特徴とする利得切換
え増幅回路。(1) An amplifier that flows current from a common load energized by a power supply to a common constant current source in response to an input signal and extracts the load voltage as an output, and includes a common load and the common load. The first . second and third differential amplifiers; a switching circuit connected to the differential amplifier and selectively enabling one of the differential amplifiers in response to an input signal; and the switching circuit. and a common single constant current SMM connected to the gain switching amplifier circuit.
異なった直流電圧でプルアップされた差動増幅器用スイ
ッチング素子と、 前記スイッチング素子を入力信号に応じて切換える信号
選択用スイッチング素子とを備えたことを特徴とする特
許請求の範囲第１項記載の利得切換え増幅回路。(2) The switching circuit includes: a differential amplifier switching element connected in series to each of the differential amplifiers, and whose input electrodes are pulled up with different DC voltages in advance; 2. The gain switching amplifier circuit according to claim 1, further comprising a switching element for selecting a signal to be switched.
的に有効化する第１．第２の差動増幅器選択用スイッチ
ング手段と、 再生信号に応答して前記第３の差動増幅器を選択的に有
効化する第３の差動増幅゛器選択用スイッチング県子と
を備えたことを特徴とする特許請求の範囲ｗｉ項記載の
利得切換え増幅回路。(3) The switching circuit is configured to switch the first switching circuit in response to the recording signal. The first differential amplifier selectively enables the second differential amplifier. A switching device for selecting a second differential amplifier; and a switching predetermined switch for selecting a third differential amplifier that selectively enables the third differential amplifier in response to a reproduction signal. A gain switching amplifier circuit according to claim wi, characterized in that:
チング手段は、 色信号に応答して前記第１の差動増幅器を選択的に有効
化する第１の差動増幅器選択用スイッチング素子と、 バースト信号に応答して前記第２の差動増幅器を選択的
に有効化するＭ２の差動増幅器選択用スイッチング素子
とを備えたことを特徴とする特許請求の範囲第３項記載
の利得切換え増幅回路。(4) 1111 above. The second differential amplifier selection switching means includes: a first differential amplifier selection switching element that selectively enables the first differential amplifier in response to a color signal; and a first differential amplifier selection switching element that selectively enables the first differential amplifier in response to a chrominance signal; 4. The gain switching amplifier circuit according to claim 3, further comprising an M2 differential amplifier selection switching element that selectively enables the second differential amplifier.
幅器が相対的に低利得であり、第２の差動増幅器が相対
的に＾利得であることを特徴とする特許請求の範囲Ｍ’
ｌ記載の利得切換え増幅回路。(5) Item 1 above. Claim M' wherein the second differential amplifier is characterized in that the first differential amplifier has a relatively low gain and the second differential amplifier has a relatively high gain.
The gain switching amplifier circuit described in l.
号、バースト信号に応答して、前記第１゜第２の差動増
幅器用スイッチング素子をスイッチングする信号選択用
スイッチング素子を備えたことを特徴とする特許請求の
範囲路４項記載の利得切換え増幅回路。(6) Item 1 above. The second differential amplifier further includes a signal selection switching element that switches the first and second differential amplifier switching elements in response to a color signal and a burst signal. A gain switching amplifier circuit according to claim 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8188582A JPS58197906A (en) | 1982-05-13 | 1982-05-13 | Amplifier circuit for switching gain |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8188582A JPS58197906A (en) | 1982-05-13 | 1982-05-13 | Amplifier circuit for switching gain |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS58197906A true JPS58197906A (en) | 1983-11-17 |
Family
ID=13758899
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8188582A Pending JPS58197906A (en) | 1982-05-13 | 1982-05-13 | Amplifier circuit for switching gain |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58197906A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4950040A (en) * | 1988-04-22 | 1990-08-21 | Asea Brown Boveri Aktiengesellschaft | Measuring range selection switch |
| EP1049249A1 (en) * | 1999-04-30 | 2000-11-02 | Lucent Technologies Inc. | Variable gain amplifiers |
-
1982
- 1982-05-13 JP JP8188582A patent/JPS58197906A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4950040A (en) * | 1988-04-22 | 1990-08-21 | Asea Brown Boveri Aktiengesellschaft | Measuring range selection switch |
| EP1049249A1 (en) * | 1999-04-30 | 2000-11-02 | Lucent Technologies Inc. | Variable gain amplifiers |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4256980A (en) | Electronic switchover circuit | |
| US4249136A (en) | PWM Signal power amplifier | |
| JPS58197906A (en) | Amplifier circuit for switching gain | |
| JPS6032367B2 (en) | switch circuit | |
| JPH0223089B2 (en) | ||
| US4001731A (en) | Device for optionally realizing two mutually complementary functions | |
| US4056783A (en) | Linear sound amplifier circuit | |
| JPH0129889Y2 (en) | ||
| JPS58197905A (en) | Amplifier circuit for switching gain | |
| JP3051553B2 (en) | Magnetic recording / reproducing device | |
| JPH02226912A (en) | Switching circuit | |
| JPH0528825Y2 (en) | ||
| JP2547732B2 (en) | Limiter circuit | |
| JPH0743807Y2 (en) | Tape player | |
| JPS5864605A (en) | Magnetic recording and reproducing device | |
| JP2577728B2 (en) | Magnetic recording / reproducing circuit | |
| JPS6338122B2 (en) | ||
| JPH0115024Y2 (en) | ||
| KR910005774Y1 (en) | Amplification circuit for control signal | |
| JP2512037B2 (en) | Output signal switching device | |
| JPH0629764Y2 (en) | High frequency compensation circuit | |
| JP3361911B2 (en) | VTR device and mute circuit used therefor | |
| JPH0326687Y2 (en) | ||
| JPH0633700Y2 (en) | Signal addition on / off circuit | |
| JPH0528596Y2 (en) |