JPS583117A - Magnetic recorder and reproducer - Google Patents

Magnetic recorder and reproducer

Info

Publication number
JPS583117A
JPS583117A JP56100821A JP10082181A JPS583117A JP S583117 A JPS583117 A JP S583117A JP 56100821 A JP56100821 A JP 56100821A JP 10082181 A JP10082181 A JP 10082181A JP S583117 A JPS583117 A JP S583117A
Authority
JP
Japan
Prior art keywords
waveform
signal
recording
waveforms
input terminal
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
Application number
JP56100821A
Other languages
Japanese (ja)
Inventor
Hideaki Uchikura
内「ぞう」 英明
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP56100821A priority Critical patent/JPS583117A/en
Publication of JPS583117A publication Critical patent/JPS583117A/en
Pending legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10Digital recording or reproducing
    • G11B20/10009Improvement or modification of read or write signals
    • G11B20/10046Improvement or modification of read or write signals filtering or equalising, e.g. setting the tap weights of an FIR filter
    • G11B20/10212Improvement or modification of read or write signals filtering or equalising, e.g. setting the tap weights of an FIR filter compensation for data shift, e.g. pulse-crowding effects

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Digital Magnetic Recording (AREA)
  • Manipulation Of Pulses (AREA)
  • Dc Digital Transmission (AREA)

Abstract

PURPOSE:To decrease the peak shift without deteriorating the signal-to-noise ratio like timing correction at recording, by compensating the effect of a demagnetizing field produced at recording, in the stage of reproduction. CONSTITUTION:An input from an input terminal 61 is given to one input terminal 66 of a differential amplifier 64 via a delay circuit 62. The input signal is divided into a specified voltage dividing ratio at a voltage-divider 65 and given to another input terminal 67 of the differential amplifier 64. Waveforms 71-74 show waveforms which appear at the input terminal 66 of the amplifier 64 after a delay at the delay circuit 62. Waveforms 72-74 adding a waveform 75 to the waveforms 71-74 are outputted from the output of the differential amplifier 64. Through the operation stated above, the waveform having widened front edge as shown in the 71 subject to the demagnetizing field of the front bit of a magnetized medium is made thin, and the peak shift of the reproduced waveform shown in the overlapping can be reduced.

Description

【発明の詳細な説明】 本発明は、磁気記録再生装置、特にその再生回路に関す
る。
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording/reproducing device, and particularly to a reproducing circuit thereof.

磁気記録再生装置の一般的な記録再生回路は、第1図に
示すように、書込みデータが哲込みデータ入力端子3に
入力されると 変開器4によって所定のコード変換が成
され、書込み回路5によって磁気ヘッド1のコイル6に
書込み電流が供給され、磁気記録媒体2に磁化情報とし
て、書込みデータが記録される。書込み電流の一例を第
2図の21に示す。
As shown in FIG. 1, in a general recording and reproducing circuit of a magnetic recording and reproducing device, when write data is input to a written data input terminal 3, a predetermined code conversion is performed by a transformer 4, and the write data is input to the write circuit. 5 supplies a write current to the coil 6 of the magnetic head 1, and write data is recorded on the magnetic recording medium 2 as magnetization information. An example of the write current is shown at 21 in FIG.

再生時は記録媒体2の磁化情報が、磁気ヘッド1によっ
て検出され、コイル6に信号電圧全誘起する。この波形
の一例全第2図の22に示す。
During reproduction, magnetization information of the recording medium 2 is detected by the magnetic head 1, and a full signal voltage is induced in the coil 6. An example of this waveform is shown at 22 in FIG.

読出し電圧22を読出し増幅器7で増幅し、ピーク検出
器9で、読出し波形のピークタイミングに対応したピー
クパルスを検出する。−例を第2図の23に示す。この
際、記録されたタイミングに対し、検出されたピークパ
ルスのタイミングは第2図の24.25のごとくずれて
検出される。これは、前後に記録された磁化情報の干渉
によるものである。ピークパルスは同期発振器11およ
び、復調回路13に供給され、同期発振器11では、ピ
ークパルスの平均クロック周波数に同期したクロック信
号全発生し、そのクロックによってデータ弁別ウィンド
パルスを発生しく第2図の26)復調回路で、弁別ウィ
ンド内にピークパルスが有るか無いかで読出し信号を論
理弁別し、読出しデータパルスとして出力端子14に出
力する。
The read voltage 22 is amplified by the read amplifier 7, and the peak detector 9 detects a peak pulse corresponding to the peak timing of the read waveform. - An example is shown at 23 in FIG. At this time, the timing of the detected peak pulse is shifted from the recorded timing as shown at 24.25 in FIG. 2. This is due to interference between magnetization information recorded before and after. The peak pulse is supplied to a synchronous oscillator 11 and a demodulation circuit 13, and the synchronous oscillator 11 generates a clock signal synchronized with the average clock frequency of the peak pulse, and uses the clock to generate a data discrimination wind pulse. ) A demodulation circuit logically discriminates the read signal depending on whether or not there is a peak pulse within the discrimination window, and outputs it to the output terminal 14 as a read data pulse.

この一連の復調動作の時、記録された磁化情報の干渉の
ため、検出されたピークパルスは、記録タイミングに対
し、相対的にずれて検出される場合がある。このことを
一般的にピークシフトと呼んでいるが、このピークシフ
トが大きくなると、所定の弁別ウィンドから飛び出した
り、余分に混入したシして、データエラーを引き起す。
During this series of demodulation operations, the detected peak pulse may be detected with a relative shift from the recording timing due to interference of recorded magnetization information. This is generally called a peak shift, and if this peak shift becomes large, the signal may jump out of a predetermined discrimination window or may be mixed in excessively, causing data errors.

第3図に記録電流の一例と、それに対応するピークシフ
トの一例を示す。一般にピークシフトは、磁化反転間隔
が、前後で非対称の場合、その磁化情報の干渉が非対称
になるため発生するが、第3図の区間32および区間3
3のそれぞれの中心磁化反転部は前後の磁化反転間隔が
対称であっても、そのピークシフトは37.38のよう
に違りた値全持ってしまう。これは記録時に、既に記録
された前の磁化パターンから発生する減磁界が重畳して
記録されるためで、全て記録したいタイミングよシも前
にシフトして記録されてしまう。このシフトは減磁界が
大きい程大きくなるので、磁化反転間隔の小さい区間3
3の方が磁化反転間隔の大きい区間32より大きくなっ
てしまう。ピークシフト39および40は、減磁界によ
る効果と既に説明した磁化反転間隔の非対称による効果
の重畳して発生したものである。
FIG. 3 shows an example of a recording current and an example of a corresponding peak shift. In general, a peak shift occurs when the magnetization reversal interval is asymmetric between the front and back, and the interference of the magnetization information becomes asymmetric.
Even if the magnetization reversal intervals before and after the central magnetization reversal portions of 3 are symmetrical, their peak shifts will have different values such as 37.38. This is because during recording, the demagnetizing field generated from the previous magnetization pattern that has already been recorded is superimposed on the recording, and the timing at which all recording is desired is also shifted before the recording. This shift increases as the demagnetizing field increases, so the section 3 where the magnetization reversal interval is small
3 is larger than the section 32 where the magnetization reversal interval is large. The peak shifts 39 and 40 are caused by the superposition of the effect due to the demagnetizing field and the effect due to the asymmetry of the magnetization reversal interval described above.

これらのピークシフト全補償するために従来実施されて
いた方法は、第4図のように、記録電流の反転タイミン
グ全予想されるピークシフトの方向と逆方向にあらかじ
めシフトして記録する方法である。記録点45では前後
の磁化反転間隔が非対称のため後側にピークシフトが発
生するので、時間47だけ前にシフトして記録される。
The conventional method for fully compensating for these peak shifts is to record by shifting the recording current reversal timing in advance in the opposite direction to the expected peak shift direction, as shown in Figure 4. . At the recording point 45, since the magnetization reversal interval before and after is asymmetrical, a peak shift occurs on the rear side, so the recording is performed with a shift forward by a time 47.

その結果磁化反転48および49は通常の磁化反転間隔
よりも時間(46+47)だけ小さくなシ、磁化干渉が
大きくなるので再生信号電圧が小さくなり、信号対雑音
比が悪化する原因となっていた。
As a result, the magnetization reversals 48 and 49 are shorter than the normal magnetization reversal interval by time (46+47), and the magnetization interference increases, resulting in a reduction in the reproduced signal voltage and a deterioration of the signal-to-noise ratio.

本発明は、信号対雑音比全悪化させること無しに、記録
された前ビットの減磁界による記録時のピークシフトを
補償し、読出しデータの信頼度を向上させた磁気記録再
生装置を提供するものである。
The present invention provides a magnetic recording/reproducing device which compensates for the peak shift during recording due to the demagnetizing field of the previous recorded bit without deteriorating the overall signal-to-noise ratio, and improves the reliability of read data. It is.

本発明は、磁気記録再生装置の再生回路において、磁気
ヘッドからの再生信号全遅延させて第1の信号全発生さ
せる遅延回路と、前記再生信号電圧1の信号振幅より小
さくなるように減衰させた第2の信号を発生させる減衰
器と、前記第1の信号と前叫第2の信号の差金発生させ
る減算回路とによって構成されることを特徴とする。
The present invention provides a reproducing circuit for a magnetic recording/reproducing device including: a delay circuit that delays the entire reproduction signal from a magnetic head to generate a first signal; The present invention is characterized in that it is comprised of an attenuator that generates a second signal, and a subtraction circuit that generates a difference between the first signal and the second signal.

記録時に既に記録されている直前の磁化パターンの減磁
界が重畳して記録されるため、記録された磁化パターン
が歪んでしまう。この歪は記録された磁化パターン列を
孤立磁化反転再生信号の重ね合さったものとして個々の
孤立磁化反転再生信号に分離してみると、ちょうど孤立
磁化反転再生信号の前線の立上り時間が大きく、幅の広
がった波形となるので、再生時にその前縁の幅を小さく
して、減磁界の影響全補償するものである。
During recording, the demagnetizing field of the immediately previous magnetization pattern that has already been recorded is superimposed and recorded, so the recorded magnetization pattern is distorted. This distortion occurs when the recorded magnetization pattern sequence is separated into individual isolated magnetization reversal reproduction signals as a superposition of isolated magnetization reversal reproduction signals. Since the waveform becomes wide, the width of its leading edge is made small during reproduction to fully compensate for the effects of the demagnetizing field.

次に本発明の笑施例について図面全参照して説明する。Next, embodiments of the present invention will be described with reference to all the drawings.

5− 第5図は孤立磁化反転再生波形の例を示す。5- FIG. 5 shows an example of an isolated magnetization reversal reproduction waveform.

52−53は波形のピークから降ろした中心線51にほ
ぼ対称な波形であり、実際に孤立磁化反転再生波彫金は
ぼ対称にすることは容易である。
52-53 are waveforms that are approximately symmetrical to the center line 51 drawn from the peak of the waveform, and in fact, it is easy to make isolated magnetization reversal reproducing wave engraving almost symmetrical.

第3図の36に、31のような記録電流の場合に発生す
るピークシフトの例を示したが、このピークシフト全発
生させるような孤立磁化反転再生波形全演算によシ求め
てみると、第5図54のように前縁が広がった形となる
。とれは既に説明したように記録時に既(記録された前
ビットから発生する減磁界が重畳することによる影響で
ある。
36 in FIG. 3 shows an example of the peak shift that occurs in the case of a recording current like 31, but when we calculate the isolated magnetization reversal reproduction waveform to cause all of this peak shift, we obtain the following: The leading edge becomes wider as shown in Fig. 54. As already explained, the warpage is caused by the superimposition of the demagnetizing field generated from the previous recorded bit during recording.

第6図に本発明の一実施例を示す。本発明の回路は、第
1図の従来の回路の読出し増幅器7と、ピーク検出器9
の間に挿入されるのが現実的である。61は本回路の入
力端子で入力信号は遅延回路62を経て差動増幅器64
の一方の入力端子66に接続され、また入力信号は分圧
器65によって所定の分圧比に分圧され差動増幅器64
の他方の入力端子67Vc接続されている。抵抗63は
遅延回路62の終端抵抗である。差動増幅器64−6 
= で入力端子66と67のそれぞれに現われた信号電圧の
差が増幅され、出力端子68に出力する。
FIG. 6 shows an embodiment of the present invention. The circuit of the present invention replaces the readout amplifier 7 and peak detector 9 of the conventional circuit of FIG.
It is realistic to insert it between 61 is an input terminal of this circuit, and the input signal is passed through a delay circuit 62 to a differential amplifier 64.
The input signal is divided into a predetermined voltage division ratio by a voltage divider 65 and then passed through a differential amplifier 64.
is connected to the other input terminal 67Vc. A resistor 63 is a terminating resistor of the delay circuit 62. Differential amplifier 64-6
The difference between the signal voltages appearing at the input terminals 66 and 67 is amplified and output to the output terminal 68.

第7図は第6図の動作を説明する図で、波形’11−7
4は既に説明したように、磁化媒体の前ピットの減磁界
の影響を受けて記録された信号の再生波形を孤立波形に
分離した波形で、遅延回路62で遅延された後、差動増
幅器64の一方の入力端子66に現われた波形を示しで
ある。75は、入力波形を分圧器65で分圧して、差動
増幅器64の他方の端子67に現われた波形全労え易す
く極性を反転して示した波形で、差動増幅器64の出力
は、波形71−74と波形75を加算した波形72−7
4が出力される。以上の動作によって磁化媒体の前ピッ
トの減磁界の影響金堂けて71のように前縁が広がった
波形は細くな力、その重ね合せで示される再生波形のピ
ークシフトは軽減される。
Figure 7 is a diagram explaining the operation of Figure 6, with waveform '11-7
4 is a waveform obtained by separating the reproduced waveform of the signal recorded under the influence of the demagnetizing field of the front pit of the magnetized medium into isolated waveforms, which are delayed by the delay circuit 62 and then sent to the differential amplifier 64. 2 shows the waveform appearing at one input terminal 66 of . 75 is a waveform obtained by dividing the input waveform by the voltage divider 65 and inverting the polarity of the waveform appearing at the other terminal 67 of the differential amplifier 64; Waveform 72-7 which is the sum of 71-74 and waveform 75
4 is output. By the above operation, the influence of the demagnetizing field of the front pit of the magnetized medium, the waveform with a widened leading edge as shown in 71, is reduced, and the peak shift of the reproduced waveform represented by the superposition of these waves is reduced.

以上の説明は、前述したように再生波形全孤立波形に分
離した波形で示してメジ、実際には波形71−74およ
び72−74は観測することはできない。はぼ前後対称
な孤立波形の第6図の回路のm力波形は第7図の73−
74のように中心線に対する前縁の幅が小さくなって観
測される。これが連続パターンを記録した時、前ピット
の減磁界の影響によって前縁が広がる効果があるので結
果的に、前後対称の波形の重ね合せと同じことになり、
減磁界の影響で発生するピークシフトを減じることがで
きる。
In the above explanation, as mentioned above, the reproduced waveform is shown as a waveform separated into all isolated waveforms, and in reality, the waveforms 71-74 and 72-74 cannot be observed. The m force waveform of the circuit of FIG. 6, which has an isolated waveform that is approximately longitudinally symmetrical, is 73- in FIG. 7.
74, the width of the leading edge with respect to the center line is observed to be smaller. When a continuous pattern is recorded, the leading edge has the effect of spreading due to the demagnetizing field of the front pit, so the result is the same as a superposition of symmetrical waveforms.
It is possible to reduce the peak shift caused by the influence of the demagnetizing field.

本発明は以上説明したように、記録時に生じる減磁界の
影響全再生時に補償するもので、記録時のタイミング補
正のように信号対雑音比全悪化させることなくピークシ
フト全滅じる効果がある。
As explained above, the present invention compensates for the effects of the demagnetizing field generated during recording during reproduction, and has the effect of completely eliminating the peak shift without completely deteriorating the signal-to-noise ratio, unlike timing correction during recording.

【図面の簡単な説明】[Brief explanation of drawings]

第1図は一標的な磁気記録再生回路の実施例を示した図
、第2図は第1図の動作全説明するための各部の波形を
示した図、第3図は記録電流波形とそれによって生じる
ピークシフトの大きさの一例を示した図、第4図はピー
クシフトラ補償する従来回路の説明をするための記録電
流波形の図、第5図はピークシフトの発生ケ説明するた
めの波形の図、第6図は本発明の実施例を示す図、およ
び第7図は本実施例を説明するための波形を示した図で
ある。 1・・・・・・磁気ヘッド、2・・−・・・記録媒体、
3・・・・・・書込みデータ入力端子、4・・・・・・
変調器、5・−・・・・書込み回路、6・・・・・・磁
気ヘッドのコイル、7・・・・・・読出し増幅器、9・
・・・・・ピーク検出器、10・・・・・・ピーク検出
器出力線、11・・・・・・同期発振器、12・・・・
・・データ弁別ウィンド出力線、13・・・・・・復調
回路、14・・・・・・読出しデータ出力端子、21,
31゜41.42・・・・・・書込み電流波形、22・
・・・・・読出し波形、23・・・・・・ピーク検出パ
ルス、26・・・・・・弁別ウィンドパルス、27・・
−・・・読出しデータパルス、36・・・・・・ピーク
シフト量ヲ示すグラフ、61・・・・・・発明の実施例
の入力端子、62・・・・・・遅延回路、63・・・・
・・終端抵抗器、64・・・・・・差動増幅器、65・
・・・・・分圧器、66.67・・・・・・差動増幅器
入力端子、68・・・・・・発明の実施例の出力端子卒
Z又
Figure 1 is a diagram showing an example of a magnetic recording/reproducing circuit, Figure 2 is a diagram showing waveforms of each part to explain the entire operation of Figure 1, and Figure 3 is a recording current waveform and its corresponding waveform. Figure 4 is a diagram showing a recording current waveform to explain a conventional circuit that compensates for peak shift error, and Figure 5 is a diagram showing an example of the magnitude of peak shift caused by FIG. 6 is a diagram showing an embodiment of the present invention, and FIG. 7 is a diagram showing waveforms for explaining the present embodiment. 1... Magnetic head, 2... Recording medium,
3...Write data input terminal, 4...
Modulator, 5...Writing circuit, 6...Magnetic head coil, 7...Reading amplifier, 9...
... Peak detector, 10 ... Peak detector output line, 11 ... Synchronous oscillator, 12 ...
...Data discrimination window output line, 13...Demodulation circuit, 14...Read data output terminal, 21,
31゜41.42...Write current waveform, 22.
... Readout waveform, 23 ... Peak detection pulse, 26 ... Discrimination wind pulse, 27 ...
-... Read data pulse, 36... Graph showing peak shift amount, 61... Input terminal of embodiment of the invention, 62... Delay circuit, 63...・・・
... Termination resistor, 64... Differential amplifier, 65.
...Voltage divider, 66.67...Differential amplifier input terminal, 68...Output terminal of the embodiment of the invention Z or

Claims (1)

【特許請求の範囲】[Claims] 磁気ヘッドからの再生信号全弁用ヰ押計で遅延させて第
一の信号全発生する遅延回路と、前記再生信号振幅f、
嘱−の信号振幅に比較して小とした第二の信号全発生妊
せる減衰器と、前記第一および第二の信号の振幅差全発
生する減算回路とを具備する再生回路?有する磁気記録
再生装置。
a delay circuit that generates a first signal by delaying the reproduction signal from the magnetic head with a full-valve press meter; the reproduction signal amplitude f;
A regeneration circuit comprising an attenuator that generates a second signal whose amplitude is small compared to the original signal amplitude, and a subtraction circuit that generates the entire amplitude difference between the first and second signals. A magnetic recording and reproducing device having.
JP56100821A 1981-06-29 1981-06-29 Magnetic recorder and reproducer Pending JPS583117A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP56100821A JPS583117A (en) 1981-06-29 1981-06-29 Magnetic recorder and reproducer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP56100821A JPS583117A (en) 1981-06-29 1981-06-29 Magnetic recorder and reproducer

Publications (1)

Publication Number Publication Date
JPS583117A true JPS583117A (en) 1983-01-08

Family

ID=14283997

Family Applications (1)

Application Number Title Priority Date Filing Date
JP56100821A Pending JPS583117A (en) 1981-06-29 1981-06-29 Magnetic recorder and reproducer

Country Status (1)

Country Link
JP (1) JPS583117A (en)

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