JPS62192013A - Digital magnetic recording device - Google Patents

Abstract

PURPOSE:To improve record density by performing a write correction in a recording time so as to reduce a pattern peak shift. CONSTITUTION:Prior to a recording, a DC erasing is performed with a switching circuit 4 controlled with an appropriate timing, using an erasing head 1 and a DC power source 3. In the recording time, the direction of the DC erasing and a magnetized direction of a record pattern are compared, and in a pattern easy to generate the pattern peak shift, a relatively large correction is applied with a write correction circuit 6 when shifting from the same direction as that of the DC magnetization to the reverse direction, then the recording being performed with a recording circuit 7.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a digital magnetic recording device.

[Technical background of the invention and its problems]

In recent years, the recording density of digital magnetic recording devices has rapidly improved. High HC of media plays a role in improving recording density
The magnetic head that records on it also has a plane '11.
] There is a tendency for RZ products with a large magnetic flux density to be used. However, there are various requirements and restrictions on the heads and media that are conveniently used in actual digital magnetic recording devices due to ease of manufacturing, durability, economic efficiency, etc.
-f Mi Often cannot be used in meetings. In particular, although the other characteristics are very good, there is a pattern peak shift caused by the overlap with residual No. 1 caused by overwriting (hereinafter referred to as override modulation, QWM). There were many lfl+ combinations of heads and media that could not be used in practical equipment.

[Purpose of the invention]

This invention improves the drawbacks of the conventional S slimming mentioned above and improves it.
It is an object of the present invention to provide a digital magnetic recorder 49 VCA that can sufficiently enhance its good recording characteristics even when used in combination with a recording head medium with insufficient QWM.

[Summary of the invention]

The present invention performs DC erasing in a predetermined direction t before recording, and performs QW correction at the time of recording to reduce the pattern peak shift caused by this.
The effect of the pattern peak shift caused by M can be reduced.

〔Effect of the invention〕

According to the present invention, although the conventional recording characteristics are excellent, it is not possible to use QWM easily, and the combination of nine head media can change the phase. Therefore, it is possible to improve the recording density. Since the range of selection of head media is widened, head media that are easy to manufacture and can be manufactured at low cost can be used for summer use.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 shows an embodiment of the magnetic head used in the present invention. Direct current erasing is performed by the erasing head l before recording. As a result, the initial state of recording is uniform and P
Ru.

FIG. 3j is a schematic diagram illustrating the magnetization state when DC erasure is performed. When the digital number shown in the upper part of FIG. 3 is magnetically recorded, in an ideal state without pattern peak shift, the magnetization pattern rl is shown in Ia). However, in the actual magnetic recording process, the T
In the (110) pattern, as shown in (b), a so-called pattern peak shift occurs due to mutual interference between bits, and the bit spacing is equal to the ideal state. It spreads from to Dl. In conventional technology, QWM performs recording by passing current to a level that does not pose a practical problem, and the pattern peak shift of the e2 pattern becomes a bottleneck, making it impossible to increase the recording density.

FIGS. 4 and 5 are diagrams explaining the relationship between recording current, QWM, and recording density characteristics. Generally, if the recording area current is increased (recording current i), the QWM characteristics are improved, but the recording density characteristics tend to deteriorate and the pattern peak shift tends to increase. On the other hand, when adding a small amount of the QL flow (recording current it), the pattern peak shift becomes small, but the Q
The WM characteristics deteriorate, random peak shifts occur due to the previous history, and the overall peak shift increases.

The present invention is based on the relationship between the above-mentioned recording current, OWM, and recording density characteristics. That is, the first point of the present invention is to uniformize the initial conditions by performing direct current erasure in a predetermined direction prior to recording. FIG. 3 shows the magnetization state in this case. DC cancellation is performed on the whole in one direction (indicated by arrow B in the figure) and 7'j t&, (
(110) with less recording current than the case shown in b).
When a pattern is recorded, the shadow caused by DC magnetization, due to the error, is shifted to the side of A in the figure (if the direction of magnetization between the bits is opposite to the direction of DC erasing, it will be in the opposite direction). (shift) bit spacing becomes . Comparing (b) and (C) here, state fc) has better recording density characteristics < DI
〉D It is a goose.

FIG. 1 illustrates one embodiment of the invention. Prior to recording, DC erasing is performed using the erasing head 1 and the DC power source 3 by a switching circuit 4 controlled at an appropriate timing. During recording, the direction of DC erasure and the magnetization direction of the recording pattern are compared with respect to the recording signal 5,
In a pattern where a NO turn peak shift is likely to occur, the inset correction circuit 6 applies a relatively larger correction to the mouth for the lift in the same direction than for the a, as shown in FIG. 3 fc).

(If the direction of Mi is reversed, the opposite is true.) That is, when moving from the same direction as the direct current magnetization to the opposite direction, a relatively large correction is applied and recording is performed by the recording circuit 7. Actually, if the recording device according to the present invention is used, the recording density characteristics are good and the pattern peak shift amount is quite small. If the writing correction is performed in advance to the left in the figure, or vice versa, to the right of the alignment, which is reversed from the opposite direction to the first direction, sufficient resonance can be achieved, and in this case, the writing correction circuit can be an hour wheel.

[Example of invention song]

Furthermore, although the embodiment of the present invention shows the case where writing correction is performed, it is also possible to correct the peak shift caused by the direction of DC erasure during reproduction as well. Therefore, correction is performed only during playback. It is also possible to perform write correction of pattern peak shifts during recording and to correct peak shifts caused by DC magnetization during reproduction.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an embodiment of the present invention, Fig. 2 is a schematic diagram showing a row of magnetic heads used in the present invention, Fig. 3 is a diagram showing a state of sensitization, and Fig. 4 is a diagram showing a recording state. FIG. 5 is a diagram showing the relationship between current and QWM, and FIG. 5 is a diagram showing the relationship between recording current and recording density characteristics. l...Erasing head, 2...Record/mine (reproduction) head,
6...Writing correction circuit. Agent Patent Attorney Ken Nori Chika Kikuo Takehana Figure 1 Figure 2

Claims (1)

[Claims] It has a head that performs recording and reproduction, and an erasing head that performs direct current erasing on the entire surface of the track in a predetermined direction prior to recording. A digital magnetic recording device comprising a circuit that performs write correction during recording so as to reduce pattern peak shifts caused by DC erasing.