JPH0762883B2 - Signal regenerator for magnetoresistive heads - Google Patents
Signal regenerator for magnetoresistive headsInfo
- Publication number
- JPH0762883B2 JPH0762883B2 JP60148262A JP14826285A JPH0762883B2 JP H0762883 B2 JPH0762883 B2 JP H0762883B2 JP 60148262 A JP60148262 A JP 60148262A JP 14826285 A JP14826285 A JP 14826285A JP H0762883 B2 JPH0762883 B2 JP H0762883B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- magnetoresistive
- reproduction
- signal
- head
- 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
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/02—Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
- G11B5/09—Digital recording
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/02—Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
- G11B5/027—Analogue recording
- G11B5/035—Equalising
Landscapes
- Magnetic Heads (AREA)
- Recording Or Reproducing By Magnetic Means (AREA)
Description
【発明の詳細な説明】 ［発明の技術分野］ 本発明は、磁性媒体上に記録された信号、特にディジタ
ル記録された信号をカップル型磁気抵抗（MR）ヘッドを
用いて再生するのに有効な磁気抵抗ヘッド用の信号再生
装置に関する。Description: TECHNICAL FIELD OF THE INVENTION The present invention is effective for reproducing a signal recorded on a magnetic medium, particularly a digitally recorded signal using a coupled magnetoresistive (MR) head. The present invention relates to a signal reproducing device for a magnetoresistive head.
［発明の技術的背景とその問題点］ 周知のように、MRヘッドは寸法精度が高くかつ再生感度
が再生速度に依存しないという利点を有するので、今後
の再生ヘッドとして有望視されている。[Technical Background of the Invention and Problems Thereof] As is well known, the MR head has the advantages of high dimensional accuracy and reproduction sensitivity not depending on the reproduction speed, and is therefore regarded as a promising reproduction head in the future.
MRヘッドには種々の構成があるが、カップル型MRヘッド
にはさらに、再生感度が高い、熱誘発パルス雑音を相殺
できる。フィードスルー雑音を相殺できる等の利点があ
る。また、MR膜の両側に磁気的なシールドを施すことに
より、再生分解能を高くすることができる。Although MR heads have various configurations, the coupled MR head can further cancel the heat-induced pulse noise, which has high reproduction sensitivity. There are advantages such as cancellation of feedthrough noise. Also, by providing magnetic shields on both sides of the MR film, the reproduction resolution can be increased.
このようなカップル型MRヘッドを磁気テープ装置に適用
する場合にあっては、製造の容易さとMRヘッドの耐摩耗
性とを考慮して、一方のシールドを磁性基板、他方のシ
ールドを磁性薄膜とした非対称シールド付きカップル型
ヘッドとするのが現時点では最適であるとされている。When such a couple type MR head is applied to a magnetic tape device, one shield is a magnetic substrate and the other shield is a magnetic thin film in consideration of the ease of manufacturing and the wear resistance of the MR head. At present, it is said that a couple head with an asymmetric shield is optimal.
第２図は非対称シールド付きカップル型MRヘッド用の従
来の信号再生装置の構成説明図である。図中、１は基板
シールド、２は第1MR膜、３は第2MR膜、４は薄膜シール
ド、５は共通端子、６は第１出力端子、７は第２出力端
子・８は差動増幅器、９および10は定電流源、11は磁性
媒体上に記録された信号の移動方向である。FIG. 2 is a diagram showing the configuration of a conventional signal reproducing apparatus for a couple type MR head with an asymmetric shield. In the figure, 1 is a substrate shield, 2 is a first MR film, 3 is a second MR film, 4 is a thin film shield, 5 is a common terminal, 6 is a first output terminal, 7 is a second output terminal, 8 is a differential amplifier, 9 and 10 are constant current sources, and 11 is a moving direction of a signal recorded on the magnetic medium.
非対称シールド付きカップル型MRヘッドは、基板シール
ド１の上に第1MR膜２、第2MR膜３、薄膜シールド４がそ
れぞれ絶縁層（図示せず）を介して一定の間隔だけ離れ
て平行に配置されている。第1MR膜２および第2MR膜３の
一方の端部は、共通端子５に接続され、その他方の端部
はそれぞれ第１出力端子６および第２出力端子７に接続
されている。In the couple type MR head with asymmetric shield, the first MR film 2, the second MR film 3 and the thin film shield 4 are arranged in parallel on the substrate shield 1 with an insulating layer (not shown) at regular intervals. ing. One ends of the first MR film 2 and the second MR film 3 are connected to the common terminal 5, and the other ends are connected to the first output terminal 6 and the second output terminal 7, respectively.
そして、第１出力端子６および第２出力端子７がそれぞ
れ差動増幅器８の異なる入力端子に接続される一方、共
通端子５が接地されている。The first output terminal 6 and the second output terminal 7 are connected to different input terminals of the differential amplifier 8, respectively, while the common terminal 5 is grounded.
この状態で、第１出力端子６と接地点との間には定電流
源９が接続され、また第２出力端子７と接地点との間に
は定電流源10が接続されて、それぞれ共通端子５に向け
て第1MR膜２および第2MR膜に一定の電流が供給される。In this state, the constant current source 9 is connected between the first output terminal 6 and the ground point, and the constant current source 10 is connected between the second output terminal 7 and the ground point. A constant current is supplied to the first MR film 2 and the second MR film toward the terminal 5.
この為、第1MR膜２および第2MR膜３は磁気的に互いに逆
バイアスされる。従って、磁性媒体上に記録された信号
が矢印11方向に移動すると、第１出力端子６および第２
出力端子７にはそれぞれ微小なずれを伴った逆極性の再
生信号が発生する。Therefore, the first MR film 2 and the second MR film 3 are magnetically reverse biased to each other. Therefore, when the signal recorded on the magnetic medium moves in the direction of arrow 11, the first output terminal 6 and the second
Reproduced signals of opposite polarities with slight deviations are generated at the output terminals 7.
これらを差動増幅器８で受けて差動増幅することによっ
て、磁性媒体上に記録されている情報を再生するものと
していた。The information recorded on the magnetic medium is reproduced by receiving these by the differential amplifier 8 and differentially amplifying them.
しかしながら、カップル型MRヘッドでは、第1MR膜２と
第2MR膜３の抵抗値、抵抗変化率等の特性を同一に製造
することが極めて困難である。両MR膜の特性差は、再生
感度の差すなわち再生振幅の差となって現われる。そし
て、第１出力端子６および第２出力端子７に現われる再
生信号（孤立波）には時間のずれがあるので、従来のよ
うに再生上の対策がなんら施されない場合には、その振
幅が異なると差動増幅器８の出力側で得られる再生パル
スの前縁・後縁が非対称となる。その一例を第３図に示
す。However, in the couple type MR head, it is extremely difficult to manufacture the first MR film 2 and the second MR film 3 with the same characteristics such as resistance value and resistance change rate. The characteristic difference between the two MR films appears as a difference in reproduction sensitivity, that is, a difference in reproduction amplitude. Since the reproduced signals (isolated waves) appearing at the first output terminal 6 and the second output terminal 7 have a time lag, their amplitudes are different when no measures are taken for reproduction as in the conventional case. And the leading and trailing edges of the reproduced pulse obtained at the output side of the differential amplifier 8 are asymmetric. One example is shown in FIG.
第３図において、縦軸は、再生パルスの半値幅の前縁部
と後縁部との比で、前縁・後縁非対称を表わすものであ
る。横軸は、第1MR膜２および第2MR膜３の感度をそれぞ
れK1、K2としてK1/（K1＋K2）で両MR膜の特性差を表わ
している。In FIG. 3, the vertical axis represents the ratio of the leading edge portion and the trailing edge portion of the full width at half maximum of the reproduction pulse, and represents the leading edge / trailing edge asymmetry. The abscissa represents the characteristic difference between the first MR film 2 and the second MR film 3 with K 1 / (K 1 + K 2 ) where the sensitivity is K 1 and K 2 , respectively.
このように、前縁・後縁が非対称となると、差動増幅器
の出力信号にピークシフトが発生するので、従来の信号
再生装置の場合には再生誤りが極めて大きくなるという
欠点があった。このことは、両シールドの厚さが等しい
ヘッド構成の場合や両シールドが無いヘッド構成の場合
も同様である。As described above, when the leading edge and the trailing edge are asymmetrical, a peak shift occurs in the output signal of the differential amplifier, so that the conventional signal reproducing apparatus has a drawback that a reproduction error becomes extremely large. This is the same for a head configuration in which both shields have the same thickness and a head configuration without both shields.
また、MRヘッドの耐摩耗性を向上するために薄膜シール
ド４を薄くした場合、シールド効果の非対称によって差
動増幅器８で得られる再パルスが前縁・後縁非対称とな
り、上記と同様の欠点があった。このことは、片側のシ
ールドが無いヘッド構成の場合も同様である。Further, when the thin film shield 4 is thinned in order to improve the wear resistance of the MR head, the repulse obtained by the differential amplifier 8 becomes asymmetric between the leading edge and the trailing edge due to the asymmetry of the shield effect, and the same drawbacks as described above occur. there were. This is the same in the case of a head configuration without a shield on one side.
［発明の目的］ 本発明の目的は、両MR膜の特性差あるいはシールドの非
対称性によって生じる差動増幅器の出力側での再生パル
スの前縁・後縁非対称を整形できる信号再生装置を提供
することにある。[Object of the Invention] An object of the present invention is to provide a signal reproducing device capable of shaping the leading edge / trailing edge asymmetry of a reproducing pulse on the output side of a differential amplifier caused by a characteristic difference between both MR films or asymmetry of a shield. Especially.
［発明の概要］ 上記の目的を達成するため、本発明の磁気抵抗ヘッド用
の信号再生装置は、磁気抵抗ヘッドを構成する絶縁層で
分離され、電気的に直列接続された第１および第２の磁
気抵抗膜の両端から直列接続点へ所与の電流を供給する
ことによって磁気的に互いに逆極性にバイアスされた前
記第１および第２の磁性抵抗膜からそれぞれ出力される
磁性媒体に記録されている情報の再生信号を差動増幅す
ることで当該情報を再生する装置において、 前記第１および第２の磁気抵抗膜の特性差を無くすよう
にいずれか一方の磁気抵抗膜からの再生信号を増幅する
手段を設けたことを特徴とする。[Summary of the Invention] In order to achieve the above object, a signal reproducing device for a magnetoresistive head according to the present invention is separated by an insulating layer constituting the magnetoresistive head and electrically connected in series. Is recorded on the magnetic medium output from each of the first and second magnetoresistive films magnetically biased in opposite polarities by supplying a given current from both ends of the magnetoresistive film to the series connection point. In a device for reproducing the information by differentially amplifying the reproduction signal of the information, the reproduction signal from one of the magnetoresistive films is removed so as to eliminate the characteristic difference between the first and second magnetoresistive films. It is characterized in that means for amplifying is provided.
［発明の実施例］ 以下、本発明を実施例について詳細に説明する。Examples of the Invention Hereinafter, the present invention will be described in detail with reference to Examples.
第１図は、本発明が適用された信号再生装置の構成説明
図であって、１は基板シールド、２は第1MR膜、３は第2
MR膜、４は薄膜シールド、５は共通端子、６は第１出力
端子、７は第２出力端子、８は差動増幅器、９および10
は定電流源、12は減衰器である。従来の信号再生装置を
説明した。第２図と異なる点は、一方の出力端子例えば
第１出力端子６の再生信号を所定の割合に減衰させるた
めに、第１出力端子６と差動増幅器８との間に減衰器12
が挿入されている点にある。FIG. 1 is a configuration explanatory view of a signal reproducing apparatus to which the present invention is applied, in which 1 is a substrate shield, 2 is a first MR film, and 3 is a second MR film.
MR film, 4 thin film shield, 5 common terminal, 6 first output terminal, 7 second output terminal, 8 differential amplifier, 9 and 10
Is a constant current source and 12 is an attenuator. The conventional signal reproducing apparatus has been described. The difference from FIG. 2 is that an attenuator 12 is provided between the first output terminal 6 and the differential amplifier 8 in order to attenuate the reproduction signal at one output terminal, for example, the first output terminal 6, to a predetermined ratio.
Is at the point where is inserted.
この実施例にあっては、上記のように減衰器12を用いて
いないと、MR膜の特性差による再生パルスの前縁・後縁
非対称が第1MR膜２の再生感度が第2MR膜３のそれぞれよ
りも高いことに基づいて発生する場合である。In this embodiment, if the attenuator 12 is not used as described above, the leading edge / trailing edge asymmetry of the reproducing pulse due to the characteristic difference of the MR film is the reproducing sensitivity of the first MR film 2 and that of the second MR film 3. It is the case that occurs based on the higher than each.
これに対して、この実施例のように減衰器12を用い、そ
して、第2MR膜３の再生感度と第1MR膜２の再生感度との
比を減衰器12の利得とすることにより、減衰器12の出力
信号は第２出力端子７の出力信号と同等の振幅となるの
で、再生パルスに前縁・後縁非対称を生じない。On the other hand, the attenuator 12 is used as in this embodiment, and the ratio of the reproduction sensitivity of the second MR film 3 and the reproduction sensitivity of the first MR film 2 is used as the gain of the attenuator 12, whereby Since the output signal of 12 has the same amplitude as the output signal of the second output terminal 7, the reproduced pulse does not have a leading edge / trailing edge asymmetry.
他方、第2MR膜３の再生感度が第1MR膜２のそれぞれより
も高い場合には、減衰器12を第２出力端子７側だけに入
れて、上記のように利得調整し、再生パルスに前縁・後
縁非対称を生じないものにする。On the other hand, when the reproduction sensitivity of the second MR film 3 is higher than that of each of the first MR film 2, the attenuator 12 is placed only on the side of the second output terminal 7 and the gain adjustment is performed as described above before the reproduction pulse. Edge / rear edge asymmetry should not occur.
薄膜シールドが薄いことに起因する再生パルスの前縁・
後縁非対称を整形する場合にあっても、第１図に基づい
て説明した実施例同様に減衰器を用いればよい。Leading edge of read pulse due to thin film shield
Even when shaping the trailing edge asymmetry, an attenuator may be used as in the embodiment described with reference to FIG.
上述において、減衰器12の利得調整を行う場合には、そ
の利得を１から小さくするに従って、再生パルスの前縁
・後縁非対称を次第に対称に近付けることができる。こ
れは、第３図に示したように、MR膜の再生感度すなわち
出力振幅が変化することによって、再生パルスの前縁・
後縁非対称が変化するという現象を利用したものであ
る。In the above description, when the gain of the attenuator 12 is adjusted, the leading edge / trailing edge asymmetry of the reproduction pulse can be gradually brought closer to symmetry as the gain is reduced from 1. This is because, as shown in FIG. 3, the reproduction sensitivity of the MR film, that is, the output amplitude changes, and
It utilizes the phenomenon that the trailing edge asymmetry changes.
以上、ヘッドに起因する再生パルスの前縁・後縁非対称
の整形について説明したが、磁性媒体上の記録磁化に起
因するその前縁・後縁非対称も上記と同様に本発明によ
って整形可能である。As described above, the shaping of the leading edge / trailing edge asymmetry of the reproduction pulse caused by the head has been described, but the leading edge / trailing edge asymmetry caused by the recording magnetization on the magnetic medium can be shaped by the present invention as in the above. .
また、第１及び第２の磁気抵抗膜の特性差を無くすこと
ができればよいから、例えば一方の磁気抵抗膜からの再
生信号を減衰器に加え、他方の磁気抵抗膜からの再生信
号を１以上のｎ倍に増幅する増幅に加え、それら増幅手
段の各出力を差動増幅するようにしてもよい。Further, since it suffices to eliminate the characteristic difference between the first and second magnetoresistive films, for example, a reproduced signal from one magnetoresistive film is added to the attenuator and one or more reproduced signals from the other magnetoresistive film are added. In addition to the amplification for amplifying n times, each output of the amplification means may be differentially amplified.
［発明の効果］ 以上説明したように、本発明は、第１および第２の磁気
抵抗膜の特性差を無くすようにいずれか一方の磁気抵抗
膜からの再生信号を増幅する手段（実施例の減衰器を指
す）を設けて、磁性媒体に記録されている情報の再生信
号を差動増幅器に加え、当該情報を再生するので、従
来、差動増幅器の出力側での再生パルスの前縁・後縁が
非対称であったのを、本発明では対称に整形でき、した
がって再生誤りを激減できるという利点がある。EFFECTS OF THE INVENTION As described above, according to the present invention, means for amplifying a reproduction signal from one of the magnetoresistive films so as to eliminate the characteristic difference between the first and second magnetoresistive films (of the embodiment). An attenuator) to provide a reproduction signal of information recorded on the magnetic medium to the differential amplifier and reproduce the information. Therefore, conventionally, the leading edge of the reproduction pulse at the output side of the differential amplifier is Although the trailing edge is asymmetric, the present invention has an advantage that it can be shaped symmetrically, and thus reproduction errors can be drastically reduced.
第１図は本発明が適用された信号再生装置の構成説明
図、第２図は従来の信号再生装置の構成説明図、第３図
はMR膜特性差が再生パルスの前縁・後縁非対称に及ぼす
影響の一例を説明する図である。 ２……第1MR膜、３……第2MR膜 ５……共通端子、６……第１出力端子 ７……第２出力端子、８……差動増幅器 12……減衰器FIG. 1 is a structural explanatory view of a signal reproducing device to which the present invention is applied, FIG. 2 is a structural explanatory view of a conventional signal reproducing device, and FIG. 3 is an asymmetrical leading / trailing edge of a reproducing pulse due to a difference in MR film characteristics. It is a figure explaining an example of the influence which has on. 2 ... First MR film, 3 ... Second MR film 5 ... Common terminal, 6 ... First output terminal 7 ... Second output terminal, 8 ... Differential amplifier 12 ... Attenuator
Claims (1)
れ、電気的に直列接続された第１および第２の磁気抵抗
膜の両端から直列接続点へ所与の電流を供給することに
よって磁気的に互いに逆極性にバイアスされた前記第１
および第２の磁性抵抗膜からそれぞれ出力される磁性媒
体に記録されている情報の再生信号を差動増幅すること
で当該情報を再生する装置において、 前記第１および第２の磁気抵抗膜の特性差を無くすよう
にいずれか一方の磁気抵抗膜からの再生信号を増幅する
手段を設けたことを特徴とする磁気抵抗ヘッド用の信号
再生装置。1. A magnetic element is provided by supplying a given current from both ends of first and second magnetoresistive films which are separated by an insulating layer constituting a magnetoresistive head and electrically connected in series to a series connection point. First biased in opposite polarities to each other
And a device for reproducing the information by differentially amplifying the reproduction signal of the information recorded on the magnetic medium output from the second magnetoresistive film, the characteristics of the first and second magnetoresistive films. A signal reproducing device for a magnetoresistive head, characterized in that means for amplifying a reproduced signal from one of the magnetoresistive films is provided so as to eliminate the difference.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60148262A JPH0762883B2 (en) | 1985-07-08 | 1985-07-08 | Signal regenerator for magnetoresistive heads |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60148262A JPH0762883B2 (en) | 1985-07-08 | 1985-07-08 | Signal regenerator for magnetoresistive heads |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS629503A JPS629503A (en) | 1987-01-17 |
| JPH0762883B2 true JPH0762883B2 (en) | 1995-07-05 |
Family
ID=15448841
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60148262A Expired - Fee Related JPH0762883B2 (en) | 1985-07-08 | 1985-07-08 | Signal regenerator for magnetoresistive heads |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0762883B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5953173A (en) * | 1996-09-17 | 1999-09-14 | International Business Machines Corporation | High CMRR and sensor-disk short-circuit protection device for dual element magnetoresistive heads |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5843682B2 (en) * | 1975-07-04 | 1983-09-28 | 電気音響株式会社 | Whole head toy |
| JPS5843794B2 (en) * | 1975-12-16 | 1983-09-29 | 三洋電機株式会社 | Shiheitouno Jikikenshiyutsu Cairo |
| JPS55129910A (en) * | 1979-03-27 | 1980-10-08 | Sharp Corp | Magnetic signal reproducing device |
-
1985
- 1985-07-08 JP JP60148262A patent/JPH0762883B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS629503A (en) | 1987-01-17 |
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| LAPS | Cancellation because of no payment of annual fees |