JPS6254859A - Reverse-signal detecter circuit for reverse cassette taperecorder - Google Patents
Reverse-signal detecter circuit for reverse cassette taperecorderInfo
- Publication number
- JPS6254859A JPS6254859A JP60082364A JP8236485A JPS6254859A JP S6254859 A JPS6254859 A JP S6254859A JP 60082364 A JP60082364 A JP 60082364A JP 8236485 A JP8236485 A JP 8236485A JP S6254859 A JPS6254859 A JP S6254859A
- Authority
- JP
- Japan
- Prior art keywords
- amplifier
- light emitting
- light
- output
- magnetic tape
- 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.)
- Granted
Links
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明はリバーステープレコーダー例としてリバースカ
セットテープデク−＃に係り、特に反転信号検出回路の
発光素子、受光素子の発光を感度のバラツキに対し好適
な反転信号検出回路に関する。[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a reverse cassette tape recorder as an example of a reverse tape recorder, and is particularly suitable for controlling the light emission of a light emitting element and a light receiving element of an inverted signal detection circuit against variations in sensitivity. The present invention relates to an inverted signal detection circuit.
従来の装置は、”特公昭５５−３９０５６号に記載のよ
うであり、ランプと光電変換素子、磁気テープ、リーダ
ーテープのバラツキに対しては配慮されていなかった。The conventional device is as described in Japanese Patent Publication No. 55-39056, and no consideration was given to variations in the lamp, photoelectric conversion element, magnetic tape, and leader tape.
本発明の目的は該検出回路の発光素子及び受−光素子の
バラツキ及び反射率又は透過率の低い磁気テープ部でも
安定に動作する調整の不要なリバーステープレコーダの
反転信号反転検出回路を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide an inversion signal reversal detection circuit for a reverse tape recorder that does not require adjustment and operates stably even in the case of variations in the light emitting elements and light receiving elements of the detection circuit and in magnetic tape sections with low reflectance or transmittance. There is a particular thing.
従来発光素子、受光素子のバラツキに対し受光素子の感
度良好な点になる様に発光素子の電流を調整していたが
、本発明は受光素子の直流出力電圧が基準電圧となる様
発光素子の電流を発光素子から出力される元を通して負
帰還をかけることにより最適発光素子の電流を制御する
。Conventionally, the current of the light-emitting element was adjusted so that the sensitivity of the light-receiving element was good with respect to variations in the light-emitting element and the light-receiving element. The current of the light emitting element is optimally controlled by applying negative feedback through the source of the current output from the light emitting element.
又基準電圧を固定にした場合反射又は、透過率の低い磁
気テープの場合増幅器がカットオフとなることを防止す
るため基準電圧を可変させることにある。Further, in order to prevent the amplifier from being cut off in the case of reflection or a magnetic tape with low transmittance when the reference voltage is fixed, the reference voltage is made variable.
以下、本発明の一実施例を図により説明する。 Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
発光ダイオード１０光を磁気テープの表面に照射し、そ
の反射光を７オトトランジ・スタ２により受光し、磁気
テープ部とリーダーテープ部の一反射率の違いによる変
化分のみを淑り出す回路であるが、フォトトランジスタ
２の出力は増幅器６の逆相入力に入力され同相入力は抵
抗１１〜１３で決定され、コンデンサ６により基準電圧
としである時定数の間保持されている。増幅器３の出力
は直流動作では、発光ダイオード駆動トランジスタ７０
ペースを通して負帰還がかけられフォトトランジスタ２
の増幅器３の同相入力の基準電圧となる様に発光ダイオ
ードの電流がコントロールされる。又基準電圧は発光ダ
イオード１からのフォトトランジスタ２の間の伝達が悪
い（磁気テープの反射率が悪いため）場合トランジスタ
７のコレクタ賦圧により抵抗１１を介・して基準電圧を
下げ増幅器３がカットオフにならない様にしている。し
かし交流動作ではコンデンサ８抵抗９により負帰還量が
少なくなり、磁気テープとリーダーテープの境で発生す
る変化分についてはコンデンサ１０を通して次段へ出力
される。増幅器４は増幅器２の出力が千両方向成分の変
化に対して出力５を十出力から一出力に変えるための回
路である。This is a circuit that irradiates the surface of a magnetic tape with light emitted from a light emitting diode, receives the reflected light by a 7-channel transistor 2, and extracts only the change due to the difference in reflectance between the magnetic tape section and the leader tape section. However, the output of the phototransistor 2 is input to the anti-phase input of the amplifier 6, the in-phase input is determined by the resistors 11 to 13, and is held as a reference voltage by the capacitor 6 for a certain time constant. In DC operation, the output of the amplifier 3 is a light emitting diode driving transistor 70.
Negative feedback is applied through the pace and phototransistor 2
The current of the light emitting diode is controlled so as to become the reference voltage of the common mode input of the amplifier 3. Also, if the reference voltage is poor in transmission between the light emitting diode 1 and the phototransistor 2 (due to poor reflectivity of the magnetic tape), the reference voltage is lowered through the resistor 11 by applying pressure to the collector of the transistor 7, and the amplifier 3 I try not to get cut off. However, in AC operation, the amount of negative feedback is reduced by the capacitor 8 and the resistor 9, and the change occurring at the boundary between the magnetic tape and the leader tape is outputted to the next stage through the capacitor 10. The amplifier 4 is a circuit for changing the output 5 from 10 outputs to 1 output when the output of the amplifier 2 changes in 1,000 bidirectional components.
本発明によれば、フォトトランジスタの最適感度になる
様発光ダイオードの電流を調整しなくとも常に最適値に
保持されると同時に反射率の低い磁気テープを使用して
も安定に動作する。According to the present invention, the current of the light emitting diode is always maintained at the optimum value without adjusting the current of the light emitting diode so as to obtain the optimum sensitivity of the phototransistor, and at the same time, it operates stably even when a magnetic tape with low reflectivity is used.
図は本発明の一実施例を示す回路図である。
１・・・発光ダイオード、２・−フォトトランジスタ、
５．４・・・増幅器、５・・・出力、６，８．１０−・
・コンデンサ、７・・・発光ダイオード駆動トランジス
タ、９ 、 １１． １２． １５ ・・・抵抗。The figure is a circuit diagram showing one embodiment of the present invention. 1... Light emitting diode, 2... Phototransistor,
5.4...Amplifier, 5...Output, 6,8.10--
- Capacitor, 7... Light emitting diode drive transistor, 9, 11. 12. 15...Resistance.
Claims (1)
磁気テープの磁気テンプ部とリーダーテープ部の反射率
又は透過率の相異を検出し、磁気テープ部からリーダー
テープ部に送行が移る時、磁気録音再生ヘッドを回転又
は切換え磁気テープの送行を反転し反対側トラックの録
音又は再生を行うリバーステープレコーダに於て、受光
素子の直流出力を増幅器に入力し該増幅器の出力により
発光素子の直流電流を制御し発光素子から受光素子を通
し該増幅器へ負帰還がかけられ増幅器の別の入力に入力
された基準電圧に受光素子の直流出力電圧を保持すると
同時に該基準電圧を該発光素子の直流電流が増加した場
合小さくする様に制御することにより該磁気テープの反
射率又は透過率が低い場合、該増幅器の負帰還ループが
遮断されることを防止し、発光素子と受光素子間の伝達
量が変化した場合の変化量のみを該増幅器の出力より取
出すことにより磁気テープの磁気テープ部とリーダーテ
ープ部の境界部を探知し送行を反転させることを特徴と
するリバースカセットテープレコーダの反転信号検出回
路。Equipped with an infrared or visible light emitting element and a light receiving element,
Detects the difference in reflectance or transmittance between the magnetic balance section and the leader tape section of the magnetic tape, and when feeding moves from the magnetic tape section to the leader tape section, rotates or switches the magnetic recording/playback head to reverse the feeding of the magnetic tape. In a reverse tape recorder that records or plays back tracks on the opposite side, the DC output of the light receiving element is input to an amplifier, and the output of the amplifier controls the DC current of the light emitting element, which passes from the light emitting element to the light receiving element to the amplifier. Negative feedback is applied to the reference voltage input to another input of the amplifier to maintain the DC output voltage of the light-receiving element, and at the same time control the reference voltage to decrease when the DC current of the light-emitting element increases. When the reflectance or transmittance of the magnetic tape is low, this prevents the negative feedback loop of the amplifier from being cut off, and only changes in the amount of transmission between the light emitting element and the light receiving element are detected from the output of the amplifier. 1. A reversal signal detection circuit for a reverse cassette tape recorder, which detects a boundary between a magnetic tape section and a leader tape section of a magnetic tape by removing the magnetic tape, and reverses feeding.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60082364A JPH0727668B2 (en) | 1985-04-19 | 1985-04-19 | Reversed signal detection circuit for reverser cassette recorder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60082364A JPH0727668B2 (en) | 1985-04-19 | 1985-04-19 | Reversed signal detection circuit for reverser cassette recorder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6254859A true JPS6254859A (en) | 1987-03-10 |
| JPH0727668B2 JPH0727668B2 (en) | 1995-03-29 |
Family
ID=13772525
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60082364A Expired - Lifetime JPH0727668B2 (en) | 1985-04-19 | 1985-04-19 | Reversed signal detection circuit for reverser cassette recorder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0727668B2 (en) |
-
1985
- 1985-04-19 JP JP60082364A patent/JPH0727668B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0727668B2 (en) | 1995-03-29 |
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