JPS5868204A - Magnetic storage device - Google Patents

Abstract

PURPOSE:To obtain an improved S/N ratio, by finding the extent of a magnetic field for minimizing unerased signal components of information recorded on a recording medium previously, and then generating the magnetic field through a recording magnetic head. CONSTITUTION:A recording circuit 31 generates a current I frequency-modulated in accordance with information to be recorded, and then supplies it to a coil 22 wound around a recording head 21 to magnetize a magnetic material on a tapelike recording medium 11, thus recording the information. The recorded information is reproduced through a playback head 23 and a reproducing circuit 32. Said current I is varied to vary a recording magnetic field AT from the recording head 21, and then the minimum point of an unerased noise remains. Information is recorded while superposed upon said information by using the recording magnetic field AT to greatly reduce the unerased noise, thereby greatly improving the resolution of the playback output of the superposed information.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic storage device in which, when rewriting information, new information is recorded overlappingly (hereinafter referred to as overwriting) without erasing previously recorded information. In a storage device, the value of the recording magnetic field (generally expressed as the product of the number of windings wound around the core of the magnetic head and the value of the current flowing through the windings) when recording information is the value used in the device. The reproduction output of the highest frequency signal is determined to be maximum. However, in a magnetic storage device that performs overwriting as in the present invention, unerased signal components of previously recorded information act as noise when reproducing the overwritten information. Noise caused by this unerased signal reduces the resolution of the reproduced output of the overwritten information, making data discrimination difficult and reducing the reliability of the device.

However, since this unerased noise has a larger change with respect to the recording magnetic field than the reproduction output, it is necessary to make the unerased noise as small as possible even if the reproduction output is reduced to some extent.

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly reliable magnetic storage device that reduces such unerased noise as much as possible, improves the resolution of reproduction output of overwritten information, and facilitates data discrimination.

The present invention was made based on the result of deep research into the overwriting phenomenon, and it was discovered that there is a recording magnetic field that minimizes the residual noise. In a magnetic storage device that records information on the recording medium, the magnetic head generates a magnetic field that minimizes an unerased signal component of information previously recorded on the recording medium, and overwrites information using this magnetic field. The gist is a magnetic storage device characterized by:

Hereinafter, the present invention will be explained in detail using examples.

FIG. 1 is a diagram showing the configuration of an embodiment of a magnetic storage device according to the present invention. In the figure, a recording circuit 31 generates a frequency-modulated current according to the information to be recorded, supplies this current to a coil 22 wound around a recording conductor 21, and
A magnetic field corresponding to this current I is generated from the recording direction, and this magnetic field magnetizes the magnetic material on the moving tape-shaped recording medium 11 to record information. The information recorded in this way is reproduced by the reproduction head 23 and reproduction circuit 32.

In the present invention, information to be overwritten is erased and recorded using a recording magnetic field that minimizes residual noise. FIG. 2 is a diagram showing an example of the relationship between the recording magnetic field and the unerased noise.
By changing the current I in step 1, the recording magnetic field from the dome 21 is changed, and the unerased noise in each recording magnetic field is determined. Note that the unerased noise was measured when the number of turns of the coil 22 of the recording head 21 was 7.
Turn, the coercive force of the recording medium 11 is 265 oersted,
The thickness of magnetic 1fi is 2.5βm1 magnetic head 21.23
, and the recording medium 11 at a relative speed of 25 m/s, first recorded at 1.6 MHz, then overwritten at 3.5 MHz, and the thus recorded signal is transferred to the playback head 23.
, by the reproducing circuit 32, supplying the output signal of this reproducing circuit to a spectrum analyzer, and measuring the signal components of each frequency with this spectrum analyzer. As is clear from the figure, the recording magnetic field is 1
．． At 4AT (recording current I=200 mA), the unerased noise becomes minimum. Therefore, in this example 1.4 A T
By recording the overwritten information with a recording magnetic field of 1, the unerased noise can be significantly reduced, and the resolution of the reproduced output of the overwritten information can be greatly improved.

FIG. 3 is a diagram showing another example of the relationship between the recording magnetic field and unerased noise. The thickness is 2.5 Am.

Indicates the case where In this case, the recording magnetic field is 1.55 AT.
The unerased noise becomes minimum, and by performing overwriting with a recording magnetic field of this value, it is possible to improve the resolution of the reproduced output of the overwritten information.

As described above, according to the present invention, unerased noise caused by overwriting can be significantly reduced, and the resolution of the reproduced signal can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a magnetic storage device according to the present invention, and FIGS. 2 and 3 are diagrams each showing an example of the relationship between noise remaining after the recording magnetic field is erased. /1 car 2 diagram

Claims (1)

[Claims] 1. In a magnetic storage device in which desired information is recorded on a recording medium by a magnetic field from a magnetic head, the magnetic field is applied to the magnetic head so that the signal component remaining unerased from the information previously recorded on the recording medium is minimized. A magnetic storage device characterized in that it generates a lot of data.