JP2655064B2 - Magneto-optical disk signal detection method - Google Patents
Magneto-optical disk signal detection methodInfo
- Publication number
- JP2655064B2 JP2655064B2 JP33055793A JP33055793A JP2655064B2 JP 2655064 B2 JP2655064 B2 JP 2655064B2 JP 33055793 A JP33055793 A JP 33055793A JP 33055793 A JP33055793 A JP 33055793A JP 2655064 B2 JP2655064 B2 JP 2655064B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- detected
- recording
- magneto
- signal detection
- 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 - Lifetime
Links
Description
【0001】[0001]
【産業上の利用分野】多値記録の可能な光磁気記録再生
方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording / reproducing method capable of multi-value recording.
【0002】[0002]
【従来の技術】磁性膜からなる記録媒体上にレーザ光を
用いて記録再生消去する光磁気記録方法において記録時
のレーザ光パワーを3段階以上に切り替えることによ
り、3値以上の情報を記録媒体上に書き込むことを特徴
とする光磁気記録方法としては特開平1−290143
号公報,特開平2−267756号公報,特開平4−0
10256号公報、特開平5−169372号公報等が
知られている。これらでは再生時に未処理信号に対して
のみスライスレベルを設定しマークを検出していた。2. Description of the Related Art In a magneto-optical recording method of recording / reproducing and erasing a recording medium comprising a magnetic film by using a laser beam, information of three or more values is recorded by switching the laser light power at the time of recording to three or more stages. A magneto-optical recording method characterized by writing on the top is described in JP-A-1-290143.
JP, JP-A-2-267756, JP-A-4-0
No. 10256, Japanese Patent Application Laid-Open No. 5-169372 and the like are known. In these, a mark is detected by setting a slice level only for an unprocessed signal during reproduction.
【0003】[0003]
【発明が解決しようとする課題】従来の方式では未処理
再生信号に対してのみスライスレベルを設定しマークの
有無を検出していたが、3値記録では再生信号における
ゼロレベルと1レベル、1レベルと2レベルの差が小さ
いので、再生時の誤り率が高いという問題があった。In the conventional method, a slice level is set only for an unprocessed reproduced signal to detect the presence or absence of a mark. Since the difference between the level and the two levels is small, there is a problem that the error rate during reproduction is high.
【0004】本発明の目的は、再生時の誤り率の低い3
値記録における再生信号の検出方法を提供することにあ
る。It is an object of the present invention to provide a low error rate 3 at the time of reproduction.
An object of the present invention is to provide a method of detecting a reproduced signal in value recording.
【0005】[0005]
【課題を解決するための手段】未処理の再生信号と再生
信号を2回微分した信号の双方にスライスレベルを設
け、双方の信号検出結果を比較し、共にマークが検出さ
れなかった場合をゼロ、未処理再生信号ではマークが検
出されなかったが2回微分信号では検出された場合を
1,共に信号が検出された場合を2に対応付けることに
よる。A slice level is provided for both an unprocessed reproduced signal and a signal obtained by differentiating the reproduced signal twice, and the signal detection results of both are compared. The case where no mark is detected in the unprocessed reproduced signal but the case where the mark is detected in the twice differential signal is associated with 1, and the case where both signals are detected is associated with 2.
【0006】[0006]
【作用】未処理信号では、大きな記録レベルに対応する
信号は十分に大きいのでスライスレベルにより検出され
るが、小さな記録レベルに対応する信号は小さすぎるた
めスライスレベルにより検出されない。それに対し2回
微分信号では小さな信号レベルも強調されるのでいずれ
の信号もスライスレベルにより検出されるようになる
(図1)。従って未処理再生信号及び2回微分再生信号
の両方に対しスライスレベルを設定し双方の信号検出結
果を比較し、共にマークが検出されなかった場合をゼ
ロ、未処理再生信号ではマークが検出されなかったが2
回微分信号では検出された場合を1,共に信号が検出さ
れた場合を2に対応付けることにより、容易かつ確実に
3段階の信号レベルを検出することができる。In the unprocessed signal, a signal corresponding to a large recording level is sufficiently large to be detected by a slice level, but a signal corresponding to a small recording level is too small to be detected by a slice level. On the other hand, a small signal level is emphasized in the twice differential signal, so that any signal is detected by the slice level (FIG. 1). Therefore, the slice level is set for both the unprocessed reproduced signal and the twice-differentiated reproduced signal, and the signal detection results of both signals are compared. If no mark is detected, no mark is detected. If no unprocessed reproduced signal, no mark is detected. TAGA2
By associating the case where the signal is detected with the time differential signal with 1 and the case where both signals are detected with 2 with each other, it is possible to easily and surely detect three levels of signal levels.
【0007】[0007]
【実施例】TbFeCoからなる光磁気ディスクに対し
5mWおよび10mWのパワーで記録を行いその再生信
号を読み取ったところ、それぞれの信号の振幅は30m
Vおよび100mVであった。未記録時の再生信号は1
0mVである。これに対し50mVのスライスレベルを
設定すると10mWのパワーで記録した場合のみ再生信
号が検出された。次に5mWおよび10mWのパワーで
記録した場合の再生信号に対し2回微分を施しその信号
を検出したところ、それぞれの記録パワーに対応する信
号は100mWおよび150mWであった。この信号に
対し70mWのスライスレベルを設定すると双方の信号
レベルとも検出された。次に未処理信号に対する信号検
出と2回微分信号に対する信号検出を同時に行い、双方
の信号かマークが検出された場合を2,2回微分信号の
みから検出された場合を1,何れからも信号が検出され
なかった場合を0と対応付け、ビットエラーレートを測
定したところ1×10-6という値が得られた。EXAMPLE When recording was performed on a magneto-optical disk made of TbFeCo at a power of 5 mW and 10 mW and a read signal was read, the amplitude of each signal was 30 m.
V and 100 mV. The playback signal when not recorded is 1
0 mV. On the other hand, when a slice level of 50 mV was set, a reproduced signal was detected only when recording was performed with a power of 10 mW. Next, when a reproduced signal recorded at a power of 5 mW and 10 mW was differentiated twice and the signal was detected, the signals corresponding to the respective recording powers were 100 mW and 150 mW. When a slice level of 70 mW was set for this signal, both signal levels were detected. Next, the signal detection for the unprocessed signal and the signal detection for the second derivative signal are performed at the same time. Was not detected, the bit error rate was measured, and a value of 1 × 10 −6 was obtained.
【0008】2回微分信号に対する信号検出について
は、特開平4−162237号等公知の方法を用いるこ
とができる。For signal detection for the twice differentiated signal, a known method such as Japanese Patent Application Laid-Open No. 4-162237 can be used.
【0009】NdDyFeCoからなる光磁気ディスク
に対し10mWおよび15mWのパワーで記録を行いそ
の再生信号を読み取ったところ、それぞれの信号の振幅
は60mVおよび40mVであった。未記録時の再生信
号は20mVである。これに対し50mVのスライスレ
ベルを設定すると10mWのパワーで記録した場合のみ
再生信号が検出された。次に10mWおよび15mWの
パワーで記録した場合の再生信号に対し2回微分を施し
その信号を検出したところ、それぞれの記録パワーに対
応する信号は100mWおよび80mWであった。この
信号に対し60mWのスライスレベルを設定すると双方
の信号レベルとも検出された。次に未処理信号に対する
信号検出と2回微分信号に対する信号検出を同時に行
い、双方の信号からマークが検出された場合を2,2回
微分信号のみから検出された場合を1,何れからも信号
が検出されなかった場合を0と対応付け、ビットエラー
レートを測定したところ5×10-6という値が得られ
た。Recording was performed on a magneto-optical disk made of NdDyFeCo at a power of 10 mW and 15 mW, and the reproduced signals were read. The amplitudes of the signals were 60 mV and 40 mV, respectively. The reproduction signal at the time of unrecording is 20 mV. On the other hand, when a slice level of 50 mV was set, a reproduced signal was detected only when recording was performed with a power of 10 mW. Next, when a reproduced signal recorded at a power of 10 mW and 15 mW was differentiated twice and the signal was detected, the signals corresponding to the respective recording powers were 100 mW and 80 mW. When a slice level of 60 mW was set for this signal, both signal levels were detected. Next, the signal detection for the unprocessed signal and the signal detection for the second derivative signal are performed simultaneously, and when the mark is detected from both signals, the signal is detected when the mark is detected only from the twice differential signal. Was detected and the bit error rate was measured, and a value of 5 × 10 −6 was obtained.
【0010】TbFeCo/GdTbFeCp2層膜か
らなる光磁気ディスクに対し7mWおよび11mWのパ
ワーで記録を行いその再生信号を読み取ったところ、そ
れぞれの信号の振幅は100mVおよび30mVであっ
た。未記録時の再生信号は20mVである。これに対し
50mVのスライスレベルを設定すると7mWのパワー
で記録した場合のみ再生信号が検出された。次に7mW
および11mWのパワーで記録した場合の再生信号に対
し2回微分を施しその信号を検出したところ、それぞれ
の記録パワーに対応する信号は130mWおよび90m
Wであった。この信号に対し50mWのスライスレベル
を設定すると双方の信号レベルとも検出された。次に未
処理信号に対する信号検出と2回微分信号に対する信号
検出を同時に行い、双方の信号からマークが検出された
場合を2,2回微分信号のみから検出された場合を1,
何れからも信号が検出されなかった場合を0と対応付
け、ビットエラーレートを測定したところ2×10-6と
いう値が得られた。When recording was performed on a magneto-optical disk composed of a TbFeCo / GdTbFeCp two-layer film at a power of 7 mW and 11 mW and a read signal was read, the amplitude of each signal was 100 mV and 30 mV. The reproduction signal at the time of unrecording is 20 mV. On the other hand, when a slice level of 50 mV was set, a reproduced signal was detected only when recording was performed with a power of 7 mW. Next, 7mW
And a reproduction signal recorded at a power of 11 mW were subjected to a second differentiation, and the signals were detected. The signals corresponding to the respective recording powers were 130 mW and 90 mW.
W. When a slice level of 50 mW was set for this signal, both signal levels were detected. Next, signal detection for the unprocessed signal and signal detection for the twice-differentiated signal are performed simultaneously, and the case where the mark is detected from both signals is 2, and the case where the mark is detected only from the twice-differential signal is 1,
The case where no signal was detected from any of them was associated with 0, and the bit error rate was measured. As a result, a value of 2 × 10 −6 was obtained.
【0011】[0011]
【発明の効果】以上説明したように、本発明によれば容
易かつ確実に3段階の再生信号レベルを検出することが
でき、良好なビットエラーレートが得られる。As described above, according to the present invention, three levels of reproduced signal can be easily and reliably detected, and a good bit error rate can be obtained.
【図1】本発明の原理を示す概念図である。FIG. 1 is a conceptual diagram illustrating the principle of the present invention.
1 未処理再生信号における低レベル信号 2 未処理再生信号における高レベル信号 3 未処理信号に対するスライスレベル 4 2回微分再生信号における低レベル信号 5 2回微分再生信号における高レベル信号 6 2回微分信号に対するスライスレベル 7 スライス後の未処理再生信号 8 スライス後の2回微分再生信号 9 スライス後の信号の合成結果 Reference Signs List 1 Low-level signal in raw reproduction signal 2 High-level signal in raw reproduction signal 3 Slice level for raw signal 4 Low-level signal in twice differential reproduction signal 5 High-level signal in twice differential reproduction signal 6 Double differential signal Slice level for 7 Unprocessed reproduction signal after slice 8 Second derivative reproduction signal after slice 9 Synthesis result of signal after slice
Claims (1)
切り替えることにより、3値以上の情報を記録した記録
媒体から信号を検出する光磁気ディスクの信号検出方法
において、未処理の再生信号と再生信号を2回微分した
信号の双方にスライスレベルを設け、双方の信号検出結
果を比較し、共にマークが検出されなかった場合をゼ
ロ,未処理再生信号ではマークが検出されなかった2回
微分信号では検出された場合を1,共に信号が検出され
た場合を2に対応付けることを特徴とする、光磁気ディ
スクの信号検出方法。1. A method for detecting a signal from a recording medium on which information having three or more values is recorded by switching a laser beam power at the time of recording to three or more steps. A slice level is provided for both of the signals obtained by differentiating the reproduced signal twice, and the signal detection results of the two signals are compared. When no mark is detected, zero is obtained when no mark is detected. A signal detection method for a magneto-optical disk, wherein a case where a signal is detected is associated with 1 and a case where both signals are detected is associated with 2.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP33055793A JP2655064B2 (en) | 1993-12-27 | 1993-12-27 | Magneto-optical disk signal detection method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP33055793A JP2655064B2 (en) | 1993-12-27 | 1993-12-27 | Magneto-optical disk signal detection method |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH07192345A JPH07192345A (en) | 1995-07-28 |
JP2655064B2 true JP2655064B2 (en) | 1997-09-17 |
Family
ID=18233986
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP33055793A Expired - Lifetime JP2655064B2 (en) | 1993-12-27 | 1993-12-27 | Magneto-optical disk signal detection method |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2655064B2 (en) |
-
1993
- 1993-12-27 JP JP33055793A patent/JP2655064B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPH07192345A (en) | 1995-07-28 |
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Legal Events
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A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 19970415 |