JPH03269804A - magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To effectively suppress cross talk by interposing a magnetic shielding material between each head chip of a multitrack magnetic head and providing a correcting circuit for correcting a phase shift of a regenerative waveform due to cross talk to be generated between adjacent channels and a compensating circuit for canceling the cross talk after correcting the phase shift. CONSTITUTION:One multitrack magnetic head is composed of an assemblage of four head chips. Each head chip 1 is made by layering a magnetic thin film 6 consisting of an amorphous alloy of, for instance, Co-Nb-Zr on a ferrite core 8, and the chips 1 are connected via magnetic gaps 7 with low fusion glass 9. After winding a coil 5 around the head chip 1, a magnetic shielding material 2 consisting of a copper foil, etc., is disposed via a coil protecting material 3 such as barium titanate, etc. A signal read out by the multitrack magnetic head 20 constituted in such a way is corrected in its phase shift in the regenerative waveform due to cross talk to be generated between the adjacent channels by the phase correcting circuit 30, and is inputted to the compensating circuit 40 for canceling the cross talk between each channel after correcting the phase to carry out the signal processing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording/reproducing device, and particularly to a magnetic recording/reproducing device equipped with a multi-track magnetic head for simultaneously reproducing signals on a plurality of recording tracks on a magnetic recording medium. The present invention relates to a magnetic recording/reproducing device.

[Prior Art] Conventionally, in this type of magnetic recording/reproducing device, as a method of suppressing crosstalk occurring between adjacent channels, for example, a method of positionally shifting the windings of the magnetic head (see Utility Model Application No. 61-40709) has been proposed. ), a method of interposing a magnetic shielding material between each head chip of a multi-track magnetic head (JP-A-56-6019), and a method of providing a correction circuit to cancel crosstalk between channels (JP-A-56-111116). Publication No. 62-54871
Publication No.) etc.

[2] Problems to be Solved by the Invention] However, when attempting to fit, for example, four recording tracks into a predetermined track pitch in a magnetic recording medium, the method of positionally shifting the windings of the magnetic head, or the multi-track magnetic The method of interposing a magnetic shielding material between each head chip of the head is difficult to apply because there is actually not enough space.

Further, simply providing a correction circuit for canceling crosstalk between channels is not an effective method because the phase shift of the reproduced waveform has a large effect.

The purpose of the present invention is to eliminate such drawbacks of the prior art,
It is an object of the present invention to provide a magnetic recording and reproducing device that effectively suppresses crosstalk during signal reproduction and has excellent recording and reproducing characteristics.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a magnetic recording and reproducing device equipped with a multi-track magnetic head for simultaneously reproducing signals on a plurality of recording tracks on a magnetic recording medium. The target is

A magnetic shielding material is interposed between each head chip of the multi-track magnetic head, and a phase correction circuit corrects the phase shift of the reproduced waveform due to crosstalk occurring between adjacent channels. The present invention is characterized in that it includes a correction circuit that cancels crosstalk between each channel after correcting the phase shift.

[Function] As described above, the present invention includes a magnetic shielding material interposed between each head chip of a magnetic head, a phase correction circuit that corrects a phase shift of a reproduced waveform due to crosstalk, and a phase correction circuit that cancels crosstalk between each channel. By providing such a correction circuit, it is possible to effectively suppress crosstalk during signal reproduction through these organic interactions, thereby providing a highly reliable recording/reproducing device.

[Example] Next, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a perspective view of a multi-track magnetic head according to an embodiment, Fig. 2 is an enlarged plan view of the magnetic head, Fig. 3 is a schematic configuration diagram of a recording/reproducing device, and Fig. 4 is a crosstalk between each channel. FIG. 3 is a block diagram of a correction circuit that cancels the .

In FIGS. 1 and 2, 1 is a head chip, 2
3 is a magnetic shielding material, 3 is a winding protection material that also serves as a spacer, 4
is a slider, 5 is a winding, 6 is a magnetic thin film, 7 is a magnetic gap, and 8 is a ferrite core.

9 is a low melting point glass, 10 is a winding @g, and 11 is a contact surface with a magnetic recording medium.

As shown in the figure, in this embodiment, four head chips 1 are assembled to form one multi-track magnetic head. The second head chip 1 has a ferrite core 8
A magnetic thin film 6 made of, for example, an amorphous alloy of Co--Nb--Zr is laminated thereon and bonded with a low melting point glass 9 via a magnetic gap 7. By using this head chip 1, it is possible to record and reproduce information on a magnetic disk capable of high coercive force and high recording density.

After winding 5 is applied to this head chip 1, a magnetic shielding material 2 made of, for example, copper foil with a thickness of 50 μm is placed through a winding protection material 3 made of non-magnetic ceramic such as barium titanate. and combine the four head chips 1.

Sliders 4 are then bonded to both ends of these to form a multi-track magnetic head.

As shown in FIG. 3, the signal read by the multi-track magnetic head 20 is input to a phase correction circuit 30 that corrects the phase shift of the reproduced waveform due to crosstalk occurring between adjacent channels. After the phase shift of the reproduced waveform is corrected by 30, the signal is input to a correction circuit 40 that cancels crosstalk between each channel and undergoes signal processing. A phase adjustment circuit is used.

FIG. 4 is a block diagram of the correction circuit 40. In the figure, la, 1b + lc, ld are four head chips arranged in parallel as described above, 12 is a magnetic disk having a large number of recording tracks in the recording band, 13a, 13b, 13
c and 13d are amplifiers connected to the head chips la, lb, lc, and ld, respectively; 14a, 14b, 14c, and 1
4d is a coefficient unit, and 15a, 15b, 15c, and 15d are adders.

16a, 16b, 16c, L6d are equivalent groups, 17a, 1
7b, 17c, and 17d are output terminals.

Signals recorded on each recording track of the magnetic disk 12 are read out through head chips la, lb, 1e, and ld, and are read out by an amplifier 13a.

The outputs of the respective amplifiers 13a, 13b, 13c, and 13d, which are amplified by the amplifiers 13b, 13c, and 13d, are amplified by the coefficient multipliers 14a and 14b, respectively, as shown in the figure.

14c, 14d and adder 15a + 15b
It is input to +15c and 15d. For example, adder 15a
When we take
Four signals from head chips la, lb, and 1c+1d are added. Another adder 15b,
15c and 15d, similarly, four signals from the respective head chips 1 a g 1 b +lc, )d are added.

The outputs of the adders 15a, 15b, 15c, and 15d are equivalent bases 16a, 16b, and 16c.

16d, and output terminals 17a and 17b.

1.7c and 17d output signals in which crosstalk between each channel has been canceled.

Next, the operation of canceling crosstalk between each channel will be explained.

In the magnetic disk 12, the head chips 1a, lb
, lc, ld corresponding to channel 4 e.g. A, B, C
, D, 1, for example, the coefficient set in the coefficient unit 44a-1 is a value obtained by inverting the sign of the amount of crosstalk from channel B to channel A. For example, when the amount of crosstalk from channel B to channel A corresponds to 7% of channel A, the coefficient set in coefficient unit 14a-1 is -(7/100). Similarly, the coefficients set in the coefficient multiplier 14a-2 and the coefficient multiplier 14a-3 are values obtained by inverting the sign of the amount of crosstalk from channel C and channel D to channel A. In this way, the coefficients of the coefficient multipliers 14b-1 to -3, the coefficient multipliers 14cm1 to -3, and the coefficient multipliers 14d-1 to -3 are set in advance. By setting a value in which the sign of the amount of crosstalk is inverted in each coefficient unit 14 in this way, each adder 15a, 15b, 15c, and 15d outputs a value in which crosstalk between channels is canceled. .

FIG. 5 is an enlarged plan view showing a comparative example of a multi-track magnetic head, in which the magnetic shielding material 2 is not interposed between the head chips 1 in the conventional type 2 magnetic head.

Figure 6 is a crosstalk characteristic diagram, and the song AI (
Curve 1) is when the magnetic shielding material, correction circuit, and phase correction circuit are not provided, Curve 1 (2) is when the correction circuit is connected and the magnetic shielding material and phase correction circuit are not provided, Curve (3) is the case when the magnetic shielding material, correction circuit, and phase correction circuit are not provided. Curve (4) is a characteristic curve in the case of the present invention in which a correction circuit and a phase correction circuit are provided with a magnetic shielding material in the case where a correction circuit and a phase correction circuit are not provided with a shielding material in between.

The magnetic disk used for this characteristic measurement was a 3° 5 inch metal floppy disk having a coercive force of 1500 oersted, and the test was conducted at room temperature at a rotation speed of 360 r/pm.

That is, first, one recording track is created on the metal floppy using a single head (2 F:
L25MHz).

Next, one head chip (the head chip with head chip number 1 in FIG. 6) of the multi-track magnetic head (which has four head chips as described above) is brought into contact with this recording track. to read the signal. At this time, the head output, which is observed as a glow stroke on the adjacent head tip, is measured using an oscilloscope and a spectrum analyzer. Then, the phase correction circuit 30 corrects the deviation of the reproduced waveform appearing on the oscilloscope, and after that, the correction circuit 40 cancels the crosstalk between channels.

In addition, the output measured by the spectrum analyzer is expressed as a crosstalk by using the output when the recorded trunk is played back as a reference value (0 dB), and the difference with the output on other channels.

Note that, as shown by the dashed line in FIG. 6, crosstalk during reproduction is required to be -35 dB or less.

[Effects of the Invention] As is clear from the results in FIG. 6, the present invention shown in curve (4) can sufficiently reduce crosstalk to about -50 dB.

In other words, if the phase of the reproduced waveform is shifted, the effect of canceling crosstalk between channels by the correction circuit is not sufficient.Therefore, the effect can be achieved by aligning the phase of the reproduced waveform and canceling the crosstalk. .

On the other hand, in a multi-track magnetic head, the frequencies of signals read by the head vary.

Therefore, even if only the frequencies with high peak values are canceled by the correction disconnect, the effect is still insufficient.

Therefore, as in the present invention, a magnetic shielding material is interposed between each head chip of a multi-track magnetic head, and a phase correction circuit that corrects the phase shift of the reproduced waveform due to crosstalk that occurs between adjacent channels, and the phase correction circuit. By being equipped with a correction circuit that cancels crosstalk between each channel after correcting the phase shift of the reproduced waveform using a circuit, crosstalk during signal reproduction can be effectively suppressed through the interaction of these two circuits. It is.

In addition, in the above embodiment, CO-Nb was formed on the ferrite core.
Although we have described a magnetic head in which magnetic thin films made of an amorphous alloy of -Z r are laminated, other soft magnetic materials having high saturation magnetic flux density and high magnetic permeability such as crystalline Fe-5i-All (Sendust) can also be used. It is also possible to use a ferrite head.

Further, in the above embodiments, a magnetic disk was used as the magnetic recording medium, but the present invention is not limited to this.
Other magnetic recording media, such as VTR magnetic tape, can also be used.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a multi-track magnetic head according to an embodiment of the present invention. FIG. 2 is an enlarged plan view of the magnetic head, FIG. 3 is a schematic diagram of a recording/reproducing apparatus according to an embodiment of the present invention, and FIG. 4 is a correction circuit for canceling crosstalk between channels. FIG. 5 is an enlarged plan view of a multi-track magnetic head in a comparative example, and FIG. 6 is a diagram of crosstalk characteristics in a recording/reproducing apparatus of each configuration. Fig. 1 1, la, lb, lc, 1d---head chip,
2... Magnetic shielding material, 12... Magnetic disk. 14a, 14b, 14c, 14d - coefficient multiplier. 15a, 15b, 15c, 15d
--Adder, 16a, 16b, 16c
, 16 d - equal deviation amount, 30... phase correction circuit, 40... correction circuit. Figure 2 Figure 5 Figure

Claims (1)

[Claims] In a magnetic recording and reproducing device equipped with a multi-track magnetic head for simultaneously reproducing signals from a plurality of recording tracks on a magnetic recording medium, a magnetic shielding material is interposed between each head chip of the multi-track magnetic head, and adjacent a phase correction circuit that corrects a phase shift in a reproduced waveform due to crosstalk occurring between channels, and a correction circuit that cancels crosstalk between each channel after the phase correction circuit corrects a phase shift in a reproduced waveform. A magnetic recording/reproducing device comprising: