SU1272354A1 - Method of visualizing of magnetic signal pattern - Google Patents

Abstract

The invention relates to magnetic recording of signals and can be used in information recording and storage systems. The purpose of the invention is to expand the dynamic range of magnetic sialogram visualization. The magneto-optical element 2 is affected by the polarized light of the microscope 4 and the magnetic fields scattered by the waveform records of the magnetic recording medium. At the same time, the element 2 is acted upon by the alternating magnetic field of the solenoid 5 alternating in time in the direction in which the spatial component of this field is parallel to the axis of magnetization of the element 2, more than 1 of the coercive force of the magneto-optical element 2. The alternating magnetic field provides the visibility of the magnetic trace of the magnetic carrier both sexes. The method is used both for direct visualization of signals and for inputting them into optical information processing systems. 3 il. (/

Description

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The invention relates to a technique of magnetic recording of signals, in particular to the visualization of magnetic waveforms, and can be used in information recording and storage systems in optical data processing devices.

The purpose of the invention is to expand the dynamic range of the visualization of magnetic waveforms.

FIG. 1 shows a dynamic rendering mode; in fig. 2 - the same, static; in fig. 3 is a block diagram of a device implementing the method.

A device that implements the method contains a substrate 1 with a magneto-optical element 2 (film B containing a ferro-garnet), a magnetic recording medium 3 with a waveform record, a polarization microscope 4 and a solenoid 5.

The essence of the method is as follows.

The dynamic range of visualization of the analyzed signal is limited by the coercivity of the magneto-optical material (He) and the field of total reversal (Hn), while the main limitation is the lack of visualization of the waveform, whose field is lower than Hc-D to extend the dynamic range of the visualization of the waveforms in the process of visualization, except for on the magneto-optical element of polarized light and magnetic fields scattered by the signal recordings of a magnetic recording medium, on a magneto-optical system The magnetic element of the recording medium is affected by a reference (HF) magnetic field alternating in time (for example, a sinusoidal meander): In this case, its direction is chosen such that the amplitude Nol of the Spatial component of the magnetic field parallel to the axis of the easy magnetization of the magneto-optical element is equal to . In the limiting case, the direction of the Hop coincides with the axis of easy magnetization. An alternating reference field is selected to provide a visualization of the waveform of a magnetic carrier of negative and positive polarity. During the positive half-period of the Hop reference field (Fig. 1), the magneto-optical element 2 is affected by the Hop- | -H field, which corresponds to point a on the hysteresis loop of the magneto-optical element, since Hop +, and when Hop is reduced, the magnetization of the magneto-optical element will change in accordance with a private hysteresis loop. The magnitude of the magnetic field Nod-bNz corresponds to the point

in on a private hysteresis loop. With a new increase in Hop, the magnetization increases along the private hysteresis loop and returns to point a. The center of the private hysteresis loop is shifted along the H axis by an amount Nz and EZ along the B axis. If this is the same

If the magneto-optical element is observed in polarized light, then a dynamic visualization of the signal occurs.

The frequency of the reference field {, „is selected in accordance with the desired imaging mode. For example, in the mode of visual observation Hz (higher than the inertia of the eye), and in the mode of real-time reproduction of reproduction. The maximum frequency of the reference field from above is limited by the speed of displacement of the domain wall.

Along with the dynamic rendering mode, static mode is also possible. In this case, the magneto-optical element is affected by the alternating reference field falling in time (Fig. 2).

Due to the presence of a hysteresis curve in the magneto-optical element, a cyclic reversal of its elements is carried out by a supporting falling field acting simultaneously with H: whose intensity at the initial moment is greater than He and varies according to the curve shown in FIG. 2. In this case, the final magnetization of the elements is established as a result of the gradual contraction of the individual hysteresis loops to the magnetization of Bc. Simultaneous exposure to polarized radiation allows visualization.

The device that implements the method works as follows.

The magneto-optic element 2, for example, a Bi film containing ferro-granate and grown by liquid-phase epitaxy on the substrate 1 and a magnetic recording medium 3 with a signalogram, is affected by polarized polarization microscope 4 and the alternating magnetic field of a solenoid 5 changing in time. the axis of the solenoid, and its magnetic field parallel to the axis.

Consequently, the system is affected by a time-varying magnetic field directed in space parallel to the axis of easy magnetization.

The method can be used both for the purpose of direct visualization of signals and for their input into optical information processing systems, where the problem of expanding the input dynamic range is particularly acute.

Claims (1)

Invention Formula A method of visualizing a magnetic waveform, in which an image of a visualized signal is formed by applying polarized light to a magneto-optical element, which is also affected by the magnetic fields of the recording track of the visualized signal of the magnetic recording carrier, characterized in that in order to expand the dynamic range of the magnetic waveform visualization, simultaneously with the influence of polarized light and the magnetic fields of the scattering track of the visualized signal recording, on the magnet an optical element an additional magnetic field alternating in time in the direction in which the spatial component of this field, parallel to the axis of magnetization of the magneto-optical element, is greater than the coercive force of the magneto-optical element.