SU1764081A1 - Non-mechanical scanned magnetic head - Google Patents

Description

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(21) 4850715/10 (22) 07/18/92 (46) 09/23/9.Byul. No. 35

(71) Research Institute for Measuring Engineering

(72) B.P.Turchenev, M.V. Koscheev and M.A.Apartsev

(56) Efimov E.G. Magnetic heads, M, Energie, 1976, p.

Efimov E.G. Magnetic heads, M., Energie, 1976, p.55, fig.40 a. (54) MAGNETIC HEAD WITH NON-MECHANICAL SCANNING

(57) Use: The invention relates to magnetic recording means, in particular to magnetic heads for horizontal recording-reproduction of television signals. Summary of Invention: Magnetic Head

contains a case of two semi-blocks, 2p working half-cores with 2p working windings, a contact board, four additional half-cores, 2xp + 1 front, 2xp + 1 rear half-liner of the same material as the half-cores, 2p of additional windings and two pads of material with a small induction saturation. The workers and additional half-hearts, the back and front half-shells of one semi-block together form one detail. The pairs of working windings are connected in parallel through the board to the recording signal source. Additional windings are connected in pairs and counter to the MDS action and connected to the phases of the P-phase control signal source. 3 silt

The present invention relates to magnetic recording means, namely, magnetic heads for lower-level recording-reproduction of television signals and can be used to create video recorders.

The known magnetic head for horizontal recording-reproduction of television signals with electromagnetic scanning (Efimov EG Magnetic heads, M., Energie, 1976, p. 96). It contains three magnetic circuits with windings, the poles of the second magnetic conductor being introduced into the working gap of the first working magnetic conductor used for recording-reproduction, and the third magnetic conductor connected to the second through non-magnetic wedges. Periodic movement of the recording area along the working gap is made by changing the position of the compensation zone in the poles of the second magnetic circuit.

WITH

flown by oppositely directed flows of the second and third magnetic conductors.

This head allows for a high recording speed at normal carrier speed and low wear on the head-to-head pair. The head is fixed and, thereby, eliminating the need to synchronize the movement of the head and the carrier.

The disadvantage of this head is low surface recording density, established by a constructively wide working gap, as well as structural complexity, low workability associated with the need for precise joining of several different types of magnetic cores. In addition, the head is characterized by low noise immunity, which is caused, on the one hand, by the so-called the effect of recording (erasing) a wide slit into which

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the gap turns together with the poles in a state of low permeability, and on the other hand, a small output signal during reproduction due to large scatter streams caused by the discrepancy between the dimensions of the print and the working head.

The closest to the technical nature of the present invention is a magnetic head with non-mechanical scanning described in the book Efimova E.G. Magnetic heads, M., Energii, 1976, p.55, fig.40a. It contains a case consisting of two semi-blocks interconnected by clamping screws, 2p working half-cores with 2p working windings connected in pairs and in coordination according to the action of a magnetomotive force (MDS) and a contact board. Each half-block has grooves for installing half-cores with windings. The terminals of the windings are soldered to the board contacts. The working clearances of all heads are located on the same line. The windings of the corresponding half-cores in the semi-blocks are connected in pairs and consistently according to the action of the MDS, so that when a recording signal is applied to them in the core consisting of two half-cores, a circular magnetic flux is formed. Accordingly, during reproduction, the circular magnetic flux from the print on the tape causes a consistent direction of the EMF in the windings, which increases the reproduced signal. Two half-cores with two windings form one channel of recording-reproducing head. In total, the head contains n independent magnetic recording-reproducing channels.

For the line recording of this head, the television signal is subjected to time sampling, as a result of which it is divided into n elements, separately recorded by the 5 channels of the magnetic head. During playback, the signals from each of the n channels are distributed in time, taking into account the previously performed sampling, and added together, as a result of which a total television signal, similar to the recorded one, is formed. The physical processes of recording and reproducing in magnetic heads and tape are usual for magnetic recording here.

The advantage of this design is constructive simplicity, manufacturability, it is not necessary to choose the material of three different magnetic circuits and their exact placement relative to each other. Formed narrow working gap channels

allows to increase the noise immunity of the head.

However, the disadvantage of this magnetic head remains low surface.

5, the recording density is explained by the fact that on the carrier the elementary prints are arranged in the form of longitudinal lines (tracks), the distance between which is determined by the location of the channels in

10 magnetic head. The number of longitudinal lines is equal to the number of channels n in the head and usually does not exceed 2 to 3 per 1 mm in the transverse direction of the carrier. The width of the track is equal to the width of the core of the canal of the head. Considering that the achieved longitudinal recording density is several thousand prints per 1 mm, it can be seen that the magnetic recording capabilities here are used inefficiently.

0 Directly addressing this issue by increasing the number of channels in the head is prevented by design and technological difficulties associated with the need to reduce the size of the windings, ensuring

5 high-quality narrow working gap in the thin core, etc., not yet overcome.

The aim of the invention is to increase the surface density

0 records by placing elementary prints on the carrier in the form of inclined lines (tracks), reducing the gaps between them, and also by reducing the width of the track.

5 The goal is achieved by the fact that, in a magnetic head, comprising a case consisting of two half blocks, interconnected by fastening screws, 2p working half-cores with 2p working windings connected in pairs and coordinated by the action of MDS and a contact board. Four additional half-hearts are located, located on both sides of the complex of 2p working half-core5 dechnikov and parallel (2p + 1) front and (2p + 1) rear half-inserts of the same material as the half-cores located between the half-hearts and forming together with them the same and

0 additional gaps, 2p additional windings located on half-cores, and two plates of material with low saturation induction, located on both sides of the working gap parallel to the plane of the magnetic tape, while workers and additional half-cores and front half-blocks of one half block together form one part. A pair of working windings through the contact board are connected in parallel to the source

the recording signal or to the summing playback amplifier; the additional windings are connected in pairs and counter to the MDS action; and the pair of additional windings are connected to the phases of the P-phase control signal source, for 1 chr, to 1, 2, 3 ... and p 2.

The following is an example of the implementation of the proposed head for case p 3, which is illustrated in the drawings, which shows: in Fig. 1: a) the structure of the inventive magnetic head;

b) magnetic head assembly;

b) a semi-block of the magnetic head with working and additional half-hearts, working and additional windings, front and rear half-shells;

Fig. 2 illustrates the principle of operation of the claimed magnetic head;

Fig. 3: a, b, c) control signal plots supplied to the additional windings;

d) recording signal plot;

e) plot of movement of the running section 16 in the direction of L;

e) a plot of the distribution of the intensity of the floor on the working surface of the head;

g) plot of the distribution of magnetization on the working surface of the head.

The inventive magnetic head contains (see Fig. 1): a housing consisting of two semi-blocks 1 and 2 interconnected by fastening screws 3, six working half-cores 4, forming in pairs three working cores, six working windings 5, working on half-hearts. The working windings 5 are connected in pairs and consistently according to the effect of the MAC, so that when a signal is applied to them in the working cores, a circular magnetic flux occurs. The lead wires of the windings are brought to the contacts of the contact board 6. Above and below the complex of working cores there are four additional half-cores 7, which in pairs form the top and bottom additional cores parallel to the worker. Eight front and eight bit half-inserts 8 and 13 are located between the cores. Workers 4 and additional 7 half-cores, as well as half-inserts 8 and 13 are made of the same magnetic material. In front of the magnetic head unit, they together form a single front (working) gap 9, and in the rear part - a single additional (technological) gap 10. Two pads 11 of a material with low saturation induction, for example, ferrite

located outside the front of the head, on both sides of the working gap 9 and parallel to the plane of the magnetic tape 12. On the working half-cores 4 there are six additional windings 14 connected in pairs and opposite in the action of the MDS, so that when a signal is applied to a pair of additional windings 14 the core forms opposing flows leaving

0 out cores. The pair of working windings through the contact board 6 are connected in parallel to the source of the recording signal or to the summing playback amplifier (such as an operational amplifier 5 of the adder). A pair of additional windings 14 through the contact board 6 is connected to the phases of the three-phase control signal source.

0Working and additional half-hearts 4 and 7, front and rear half-inserts 8 and 13, i.e. the entire magnetic core, except for the overlays, is a single design of a semi-block of the same

5 material, for example, ferrite or amorphous magnetic alloy. They are parts of one complex nonseparable part, but hereinafter are considered separately for convenience of presentation.

0 The arrival of the magnetic head when recording a TV signal works as follows (see fig, 2 and 3),

The pairs of additional windings 14 are supplied with phase-shifted currents (see Fig. 3,

5 a, b, c) from a three-phase (generally P-phase) source synchronized by a video signal. Under the action of these currents through the half-hearts 4 and 7, the half-liners 8 and 13 and the pads 11, i.e. the magnetic fluxes shifted in phase pass through the whole of magnesium, which, as a result of joint action, form the resultant stream consisting of the half-flows F1 and F2. Location and configuration

5 half-flows F1 and F2 at any given moment are determined by the ratio of the amplitudes and phases of the primary flows. As a result, the half-streams F1 and F2 and the separation zone between them continuously changes its

0 position, moving in the direction L along the working gap 9. In this case, the initial flows in pairs of half cores, directed in one direction, go beyond the limits of half cores and propagate 5 across the magnetic circuit. In the area of the magnetic circuit adjacent to the working surface of the magnetic head, the half-flows F1 and F2 are directed in opposite directions, as shown by the arrows in FIG. 2. They slide along the gap and do not extend beyond the magnetic core. In the zone

F1 half-stream. The floor is directed in one direction, and in the half-stream zone F - in the opposite direction. Between them there is a certain narrow border zone 15, perpendicular to the gap 9, in which the magnetic field changes direction and, therefore, passes through zero (see the dotted line in figure 2 - zone 15, as well as in fig. Ze) zone 15 moves in time with the half-flows F1 and F2 in the direction L along the gap 9, the flow in the additional windings 14 is selected so that the material of the half-cores 4 and 7 and the half-liners 8 and 13 is unsaturated, and the material of the overlays 11, on the contrary, is saturated everywhere except in narrow zone 15, where the intensity of l is close to zero (see fig. Ze, g). At the intersection of the boundary zone 15 and the working gap 9 of the rotor magnet assembly, a running recording-reproduction section 16 is formed. The recording signal supplied in parallel to all pairs of working windings 5 (see Fig. 3g) forms a circular working magnetic flux throughout the magnetic circuit. However, it is only on the running section 16 that it protrudes in the direction of the magnetic carrier 12, where it leaves on its working layer an imprint in the form of an elementary section magnetized in accordance with the instantaneous recording signal of Fig. 3. In other places, this is prevented by the low magnetic permeability of the plates 11, which are in saturation, and in other places of the boundary zone 15, besides by the absence of a gap. Moving in time along the working gap 9 in the direction L (see fig. 3 and figure 2), the running work section 16 scans the surface of the magnetic tape 12, leaving in its working layer elementary prints of an instant recording signal (FIG. 3g), which together form the recorded string. During the duration of this line, the magnetic tape 12 moves a certain distance in the V direction (Fig. 2), so that the next line is next to the previous one, and so on.

The width of the recording line on the carrier is equal to the width of the running section 16 and at a certain ratio of the values of the flows F1 and F2 and the induction of saturation of the material of the plates 11 can be reduced to several tens of micrometers. The choice of carrier speed and frequency of control signals in additional windings makes it possible to reduce the spacing between the lines to a few micrometers.

When playing, running section 16 also scans the surface.

magnetic tape 12, while only an elementary imprint at each given moment forms a working magnetic flux in the magnetic circuit and, accordingly, forms a reproduced signal at the output of one or another pair of working windings 5. In this case, the largest signal is formed in the windings closest to the running gap, and as it moves away from it

0 signal decreases. All signals from the pair of windings are added to the summing amplifier, which increases the overall return. At the same time, the circumstance that the main reproducible stream passes through

5, the closest working core allows to achieve a correspondence between the size of the print and the size of the acting head and to avoid excessive scattering flows and losses in the magnetic circuit. This is especially

0 important in the case of writing data lines.

Prints that do not currently coincide with running station 16 do not pass through the saturated material of the plates 11 and do not form a reproducible signal at the moment.

By alternately scanning the entire line, the elementary reproduced signals together form a multi-element horizontal signal corresponding to the recorded signal (see Fig. 3g). During playback, mutual synchronization of the control currents with the movement of the magnetic carrier is necessary, so that the scan falls exactly on the recorded lines. It can be realized with the help of a special impulse in the composition of the line signal (marker - see Fig. 3g). This, however, relates more to the common magnetic recording path than to the magnetic head.

0 The proposed solution has the following advantages.

Increase the surface density of the recording on the media. The gain in write density is determined by

5 that additional half-hearts, front and rear half-inserts of the same material as half-hearts, lining of material with low saturation induction, which together with working half-hearts form a single magnetic circuit, are introduced into the claimed magnetic head into the introduction of additional windings connected to the p-phase control signal, allows you to shift the zone

5 recordings of elementary prints in the transverse direction on the carrier by controlling the electromagnetic field. As a result, elementary prints on the carrier are arranged in the form of inclined lines, the intervals between which can

be reduced to several micrometers by choosing the speed of movement of the carrier and the frequencies of the control signals in the additional windings. In addition, the width of the line itself can be reduced to several tens of micrometers when choosing the ratio of the fluxes F1 and F2 for the induction of the saturation of the lining material 11.

Increasing the recording density reduces the consumption of magnetic tape.

An additional advantage of the proposed technical solution is that the continuous recording of the television signal by a stationary head without time sampling and summation during playback, as in the Bing-Crosby method, is carried out. This increases the accuracy of the recording - reproduction, the collision avoids the inherent distortions of this known method due to discretization.

In addition, the equipment is simplified, since together n recording amplifiers and n playback amplifiers, one recording amplifier and one summing playback amplifier are required.

b)

Claims (1)

Claims of the Invention Magnetic head with non-mechanical scanning comprising a body of two semi-blocks interconnected through the laying of the working gap and including 2p working half-cores with 2n working windings connected in series and in coordination, where n is the number of winding channels and the contact plate, about l and in order to increase the recording surface density by reducing the width of the track and interline spacing, the distance, four additional half-cores, 2n + 1, are introduced half-liner, 2p control windings, two linings for semi-blocks, with additional half-hearts located on both sides of the working half-hearts, 2p + 1 half-inserts located between the half-cores, 2p control windings are located on the working half-cores, the lining of each of the half blocks is associated with the working surface of the half-cores and half-inserts, which are made of the same material with saturation induction greater than the saturation induction of the lining material. Fig / Editor  - - h- - mi Fig.Z Compiled by B.Sychev Tehred M.MorgentalKorrektor N. Revska