JPH0817004A - Vertical magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To prevent reduction of the outward magnetic flux leakage to be used for reproduction by inversing the recording current in a specified section of a recording pattern at a time interval shorten than a bit length and thereby forming reversed polarity magnetization. CONSTITUTION:The recording current control device 34 determines the recording current flowing from the recording pattern 1 to the recording head 38 and controls the recording amplifier 36 to make the recording current 21 flow to the recording head 38, which vertically magnetizes the mono-layer vertical magnetizing body 39 for recording the recording current 21. At the time of reproduction, the MR head 40 reproduces the recording pattern, which is amplified using the reproducing amplifier 41 to obtain a reproduced waveform 24. In the recording pattern 1, pulsive current inversion is applied in the region where no inversion of the recording pattern occurs over two-bit lengths. Hence, pulsive reversed polarity magnetization is formed by inversing the recording current of the region where the same recording current continues over two-bit lengths at a time interval shorter than one-bit length.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perpendicular magnetic recording / reproducing apparatus of a perpendicular magnetic recording system, and more particularly to a perpendicular magnetic recording / reproducing apparatus in which deterioration of reproduced waveform is reduced.

[0002]

2. Description of the Related Art Conventionally, in a magnetic recording / reproducing apparatus, a longitudinal magnetic recording system has been used in which a recording pattern is recorded by magnetizing the film surface of a magnetic recording medium in the longitudinal direction.

In a magnetic recording medium in which a recording pattern is recorded by the longitudinal magnetic recording method, if the linear recording density becomes high and the interval between the magnetic transition points becomes small, the medium becomes unstable due to the demagnetizing field in the medium, and the magnetization becomes difficult to record. There is a drawback that.

Further, when the distance between the magnetic transition points becomes small, the magnetic transition point shift becomes conspicuous because the recorded position and the position where the magnetic transition point is actually formed are changed.

In order to compensate for this, the magnetic recording / reproducing apparatus uses recording equalization in which the timing of recording current reversal is changed in advance to reduce this effect.

On the other hand, in the perpendicular magnetic recording system, a recording pattern is recorded by magnetizing the film surface of the magnetic recording medium in the perpendicular direction.

In the magnetic recording medium in which the recording pattern is recorded by the perpendicular magnetic recording system, unlike the magnetic recording medium in which the recording pattern is recorded by the longitudinal magnetic recording system, the higher the linear recording density, the more stable and the easier the recording becomes. And the shift of the magnetic transition point as described above is small.

Therefore, the perpendicular magnetic recording system is the most suitable system for constructing a magnetic recording / reproducing apparatus with an ultrahigh density.

A magnetic recording medium used in the perpendicular magnetic recording system is a double-layer film medium having a soft magnetic backing layer (hereinafter,
There is a double-layered perpendicular magnetization medium) and a single-layered film medium without a soft magnetic backing layer (hereinafter referred to as a single-layer perpendicular magnetization medium).

The double-layered perpendicular magnetization medium requires a recording head having a structure different from the conventional one, whereas the single-layered perpendicular magnetization medium can use a conventional head for recording and reproduction, and has a double-layered film. It has an advantage that the manufacturing cost is lower than that of the perpendicular magnetization medium.

A number of papers on the perpendicular magnetic recording system have been published so far, and floppy disks coated with a barium-ferrite medium are already on the market as products using perpendicular magnetic recording.

Further, the sensitivity of the reproducing head has been increased for higher density, and a reproducing head (hereinafter referred to as MR head) using a magnetoresistive effect has been developed in place of the conventional inductive head. .

By using the MR head, the recording density has been greatly improved even in the conventional longitudinal magnetic recording medium.

Further, the partial response method is used as a high density signal processing method.

The partial response method is a method that has been used for a long time in the field of communication and can be applied to a system in which linear superposition (linearity) is established.

At present, a magnetic disk device combining a longitudinal magnetic recording system, an MR head, and a partial response system is being commercialized.

However, an example in which the perpendicular magnetic recording system, the MR head, and the partial response system are combined has not yet been known.

[0018]

FIG. 11 is a diagram showing the relationship between the recording pattern, the recording current, and the remanent magnetization perpendicular component on the magnetic recording medium in the perpendicular magnetic recording system.
FIG. 12 is a diagram for explaining the demagnetizing field in the medium in the perpendicular magnetic recording system.

Now, it is assumed that the recording pattern 1 shown in FIG. 11 is magnetized in the direction perpendicular to the film surface of the magnetic recording medium medium by using the recording current 2 shown in FIG. 11 to record the recording pattern 1.

However, as shown in FIG. 12, in the perpendicular magnetic recording medium in which the recording pattern is recorded by the perpendicular magnetic recording method, the medium demagnetizing field 113 is generated, and the medium magnetization 111 is weakened. Magnetic field 112 from magnetization 115
Serves to strengthen the medium magnetization 111.

Therefore, in the vicinity of the magnetic transition 114, the magnetic field 114 from the adjacent magnetization cancels the medium demagnetizing field 113, and the medium magnetization 111 can remain stably.
At the portion away from the magnetization transition, the perpendicular component 3 of the remanent magnetization has a characteristic of decreasing due to the demagnetizing field 113 in the medium, as shown in FIG.

FIG. 13 is a diagram for explaining a magnetic field leaking to the outside of the magnetic recording medium in the perpendicular magnetic recording system.

As shown in FIG. 13, the magnetic field leaking to the outside of the magnetic recording medium can be considered to be a magnetic field produced by a magnetic charge in which the magnetization in the medium is virtually concentrated on the front and back surfaces of the medium.

In the figure, the magnetic charges on the front surface and the back surface of the magnetic recording medium have opposite polarities.
It acts to weaken the magnetic field generated by the medium surface magnetic charge 121.

When an ideal rectangular magnetization is recorded,
The combined magnetic field of the vertical component 124 of the magnetic field from the medium surface magnetic charge 121 and the vertical component 125 of the magnetic field from the medium back surface 122 becomes an external magnetic field that leaks to the medium surface, and leaks to the outside of the magnetic recording medium that directly contributes to reproduction. The vertical component 126 of the magnetic flux is reduced in the portion away from the magnetic transition.

As described above with reference to FIGS. 11 to 13, in the magnetic recording medium in which the recording pattern 1 is recorded by the perpendicular magnetic recording method, the demagnetizing field 113 inside the medium.
Therefore, the vertical component 3 of the residual magnetization in the portion away from the magnetic transition is reduced, and the perpendicular component 12 of the leakage flux in the portion away from the magnetic transition due to the front and back surface magnetic charge in the medium.
In particular, such a phenomenon is remarkable in the single-layer perpendicular magnetization medium.

Therefore, when the recording pattern 1 recorded by the perpendicular magnetic recording system is reproduced by the MR head, the reproduction waveform of the recording pattern 1 is that portion at a portion distant from the magnetic charge transfer as shown in FIG. Amplitude decreases.

That is, in the magnetic recording medium in which the recording pattern 1 is recorded by the perpendicular magnetic recording method, there is a problem that the amplitude of the reproduced waveform is lowered at the portion away from the magnetic transition, and the linearity is impaired.

Further, noise may be superimposed on the reproduced waveform of the recording pattern 1 during the signal processing, and in that case, since the amplitude of the reproduced waveform is reduced at the portion away from the magnetic transition, noise is generated. However, there is a problem in that it is easily affected by and causes a malfunction.

Since the above-mentioned phenomenon occurs in a complicated and non-linear manner depending on the magnetic characteristics of the medium, the pattern to be recorded, and the recording density, it is difficult to make compensation on the reproducing side, and it is necessary to make some compensation at the time of recording.

As a method for performing recording equalization on a perpendicular magnetic recording medium, a technical report of the Television Society of Japan Vol. 13,
No. 60. PP. 7-12, VTR'89-25 (N
ov. 1989), when phase detection is used in a combination of recording / reproducing with a double-layered perpendicular magnetization medium and a ring head, recording is performed using a pulsed recording current, and the symmetry of the waveform that changes depending on the magnetic characteristics of the medium is improved. And a method of limiting the maximum magnetization reversal interval has been reported.

However, in this method, the information itself is recorded by the pulse-shaped recording current, and there is a problem that overwrite cannot be performed. Further, a dedicated decoder is required to limit the maximum magnetization reversal interval. It is a thing.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to reduce the demagnetizing field in the medium or the magnetic charge on the front and back surfaces of the medium in the perpendicular magnetic recording / reproducing apparatus. It is an object of the present invention to provide a technique capable of reducing the deterioration of the reproduced waveform caused by the improvement and improving the linearity.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0035]

Of the inventions disclosed in the present application, a representative one will be briefly described below.
It is as follows.

(1) The magnetic recording medium is vertically moved by a recording current generating means for generating a recording current of opposite polarity corresponding to a binarized recording pattern and a recording current output from the recording current generating means. In a perpendicular magnetic recording / reproducing apparatus comprising at least a recording head which is magnetized to record the recording pattern and a reproducing head which reproduces the recording pattern recorded on the magnetic recording medium, the recording current generating means comprises: In the binarized recording pattern, there is provided means for detecting a portion having the same value continuously for 2 bits or more and inverting the recording current of the portion at least once at a time interval shorter than the bit length. It is characterized by

(2) In the above-mentioned means (1), the recording current generating means comprises a recording current control device and a recording amplifier, and the recording current control device has a narrow pulse width in synchronization with a clock signal. An edge trigger circuit that generates a clock pulse, and 2 out of the binarized recording patterns
The clock pulse and the equalizing pulse are added to a first means for detecting a portion having the same value continuously for more than one bit and generating an equalizing pulse with a narrow pulse width delayed from the clock pulse for a predetermined time. And a means for generating an output pulse, and the recording amplifier generates a recording current which is inverted for each output pulse output from the recording current control device.

(3) In the above-mentioned means (2), the first means of the recording current control device has a first delay circuit for delaying the clock pulse for a predetermined time and a binarized recording pattern. A second delay circuit for bit-delaying, a matching circuit for matching the binarized recording pattern with the 1-bit delayed recording pattern output from the second delay circuit, and the output of the matching circuit And a logical product circuit for generating an equalized pulse having a narrow pulse width by performing a logical product with the clock pulse output from the first delay circuit and delayed for a predetermined time.

(4) In the above means (1) to (3), the reproducing head is a reproducing head using a magnetoresistive effect.

(5) In the above means (1) to (4), the magnetic recording medium is a magnetic recording medium having no soft magnetic backing layer.

(6) In the above means (1) to (5), a recording encoder for encoding input data in the front stage of the recording current control device and a demodulator for outputting demodulated data in the rear stage of the reproducing head. And is provided.

(7) In the means of (6), a precoder is provided between the recording encoder and the recording current control device, and a reproduction equalizer is provided between the demodulation device and the reproduction head. To do.

[0043]

According to the above-mentioned means, in the perpendicular magnetic recording / reproducing apparatus for recording the recording pattern by magnetizing the magnetic recording medium in the vertical direction by the recording current of the opposite polarity corresponding to the binarized recording pattern, When there is a portion having the same value continuously for 2 bits or more in the binarized recording pattern, the recording current of that portion is inverted at a time interval shorter than the bit length to generate a pulse-like signal. Since the reverse polarity magnetization is formed, it is possible to limit the maximum magnetization transition interval of the perpendicular magnetization on the magnetic recording medium and prevent the decrease of the leakage flux to the outside used for reproduction.

As a result, it is possible to prevent the deterioration of the reproduction waveform caused by the demagnetizing field in the medium of the magnetic recording medium magnetized in the perpendicular direction or the magnetic charge on the front and back surfaces of the medium and improve the linearity.

[0045]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In all the drawings for explaining the embodiments, parts having the same functions are denoted by the same reference numerals, and their repeated description will be omitted.

(Embodiment 1) FIG. 1 is a block diagram showing a schematic configuration of a magnetic recording / reproducing apparatus according to an embodiment (embodiment 1) of the present invention.

In FIG. 1, 34 is a recording current control device,
36 is a recording amplifier, 38 is a recording head, 39 is a single-layer perpendicular magnetization medium, 40 is an MR head, and 41 is a reproducing amplifier.

As shown in FIG. 1, in the first embodiment, the recording current control device 34 determines the recording current 21 to be applied to the recording head 38 from the recording pattern 1, and the recording current control device 34 controls the recording amplifier 36. Then, the recording current 21 is applied to the recording head 38 to magnetize the single-layer perpendicular magnetization medium 39 in the perpendicular direction to record a recording pattern.

At the time of reproduction, the recording pattern is reproduced by the MR head 40 and further amplified by the reproduction amplifier 41 to obtain the reproduction waveform 24.

FIG. 2 is a diagram for explaining the recording method of the recording pattern 1 in the first embodiment.

In FIG. 2, 1 is a recording pattern,
It has a portion 20 where there is no inversion in the recording pattern of 2 bits or more.

Reference numeral 21 denotes a recording current for the recording pattern 1. In the first embodiment, in the recording pattern 1, a portion 2 in which the recording pattern has no inversion of 2 bits or more,
A pulsed current reversal 25 is added.

The recording current 21 is used to magnetize the single-layer perpendicular magnetization medium 39 in the perpendicular direction to record the remanent magnetization perpendicular component 22 including the pulsed reverse polarity magnetization 26.

As a result, the maximum magnetization reversal interval is limited to the clock interval 27.

When the size of the inversion region for limiting the magnetic transition interval is sufficiently small and regular, the effect of the inversion magnetization formed by the current inversion pulse on the reproduction waveform is small and regular. .

At this time, the vertical component of the leakage flux from the single-layer perpendicular magnetization medium 39 to the outside is as shown by 23 in FIG.
This is reproduced by using the MR head 40 and reproduced waveform 2
4 can be obtained.

In the reproduced waveform 24, the amplitude is not lowered even in the portion 20 where the recording pattern 1 is not inverted, and the linearity is improved.

As a result, the perpendicular magnetic recording / reproducing apparatus of the first embodiment can be regarded as a linear system, and the signal processing method based on the linearity can be applied.

FIG. 3 shows a recording current control device 34 in FIG.
FIG. 4 is a diagram showing an example, and FIG. 4 is a waveform diagram showing operation waveforms of respective parts for explaining the operation.

The recording current control device 34 shown in FIG. 3 has a function of detecting the portion 20 in which the recording pattern has no inversion of 2 bits or more, and the pulse-shaped current inversion in the portion 20 in which the recording pattern has no inversion when this is detected. It has a function of adding 25.

As shown in FIG. 3, the recording current control device 34
Is an etch trigger circuit 73 that detects a rising edge of the clock signal 71 and generates a clock pulse 74, a latch 76 that latches the recording pattern 72, a delay circuit 77 that delays the recording pattern 72 at 1-bit intervals, and an equalizer. A logical adder 78 for generating a pulse enable 79,
A delay circuit 81 that delays the clock pulse 74 by the width τ of the current inversion pulse to generate the equalizing pulse 82, and a matching circuit 80 that creates the equalizing pulse 83 from the equalizing pulse 82 and the equalizing pulse enable 79. , And an adder 75 for producing the recording amplifier input pulse 84.

Next, the operation of the recording current control device 34 shown in FIG. 3 will be described with reference to FIG.

A clock signal 71 having a cycle of a clock interval 27 shown in FIG. 2 and a recording coded recording pattern 72 are input to the recording current control device 34.

As shown in FIG. 4, the recording current control device 34
The etch trigger circuit 73 detects the rising edge of the clock signal 71 and generates a clock pulse 74.

In addition, the delay circuit 73 uses the clock pulse 7
4 is delayed by the width τ of the pulsed current inversion 27, and the equalizing pulse 82 is output.

Further, the logical adder 78 matches the present time with the recording pattern 72 of 1 bit before, and, for example, as shown in FIG.
In the recording pattern 72 shown in FIG. 6, the equalization pulse e is detected by detecting the portion 20 in which the recording pattern is not inverted by 2 bits or more.
The enable signal 79 is output.

Further, the logical product circuit 80 uses the equalizing pulse 8
2 and the equalization pulse enable signal 79 are ANDed to generate an equalization pulse 83 delayed from the clock pulse 74 by a width τ.

Further, the adder 75 has a clock pulse 74
And the equalization pulse 83 are added and the recording amplifier input pulse 84 is added.
Is output.

The recording amplifier 36 detects the rising edge of the recording amplifier input pulse 84 output from the recording current controller 34, inverts the current, and outputs the recording current 91.

The position of the pulsed current reversal 25 can be set to a position other than that of the first embodiment, but if it is set as in the first embodiment, the configuration becomes simple.

The pulsed current reversal 25 is added to form pulsed magnetization of opposite polarity, and the amplitude of this pulse is within the range in which magnetization of opposite polarity is sufficiently recorded. Pulsed current reversal 53 shown in 5 and 5
4, the recording currents 51 and 52 to which pulsed current reversals having different magnitudes are added may be used.

FIG. 6 shows the relationship between the magnitude of the magnetization of the pulsed magnetization reversal region and the width of the pulsed current reversal when the amplitude of the pulsed current reversal is set to be the same as the amplitude of the recording current. It is a figure which shows the relationship between reproduction | regeneration output and pulsed current inversion.

Next, the determination of the width of the pulsed current reversal will be described with reference to FIG.

If the width of the pulsed current reversal is small due to the recording capacity of the recording head 38, the recording head 38 is actually used.
The magnitude 101 of the pulsed magnetization recorded in the perpendicular magnetic recording medium 39 due to the current flowing in the magnetic recording medium 39 becomes small, and if the width is further reduced, the magnetization is not inverted and becomes the same polarity as the magnetization before and after.

Further, when the pulsed reverse polarity magnetization is ideally recorded, if the width is increased, the reproduction output 102 is lowered.

Therefore, the width of the pulsed current inversion needs to be sufficiently small within the range in which the magnetization of the opposite polarity is sufficiently recorded, and in FIG. 6, it is necessary to set the width between w1 and w2. .

In the first embodiment, the single-layer perpendicular magnetization medium 39 is used as the magnetic recording medium for recording the recording pattern 1. However, it is also possible to use the double-layer perpendicular magnetization medium. It is also possible to use a reproducing head other than the MR head 40.

(Embodiment 2) FIG. 7 is a block diagram showing a schematic configuration of a recording / reproducing apparatus which is another embodiment (Embodiment 2) of the present invention.

The second embodiment is an embodiment in which the magnetic recording / reproducing apparatus of the first embodiment is applied to a recording / reproducing system of a class I partial response system.

As shown in FIG. 7, in the second embodiment, in addition to the structure of the first embodiment, a recording encoder 32 for encoding the input data 31 and a class I partial response system precoder A46. And a reproduction equalizer A43 and a demodulator A45 that outputs demodulated data 47 using the equalized signal 44.

The perpendicular magnetic recording / reproducing apparatus of the first embodiment is
A linear system can be configured, and the perpendicular magnetic recording / reproducing apparatus of the first embodiment can be applied to a partial response recording / reproducing system.

When the MR head 40 for detecting the perpendicular component of the medium magnetization is used for reproduction with respect to the single-layer perpendicular magnetization medium 39, it exhibits a low-pass type characteristic, and when the reproduction resolution is sufficiently high, reproduction is performed. The waveform has almost the same shape as the distribution of the vertical component of the leakage magnetic flux to the outside.

Next, the reproduction waveform equalization in the second embodiment will be described with reference to FIG.

A binary rectangular wave current of ± 1 is used as the recording current. When the recording data is 0, the recording current level is -1, and when the recording data is 1, the recording current level is 1.

In this case, the amplitude value of the detection point 65 of the reproduced waveform 62 corresponding to the input data "... 010" shown in the recording pattern 61 is changed to "...
The reproduction equalizer A43 performs equalization so as to obtain 0110 ... ", and the class I partial response method is applied.

The response of the magnetic recording / reproducing system of the second embodiment is close to the class I partial response channel at a certain reproducing resolution, and it is effective to apply this.

FIG. 9 is a diagram for explaining the effect when the perpendicular magnetic recording / reproducing apparatus of the first embodiment is applied to the class I partial response system.

When the recording pattern 130 shown in FIG. 9 is recorded / reproduced, in the conventional perpendicular magnetic recording / reproducing apparatus, the reproduction waveform is as shown in FIG. 131, and the reproduction equalization output from the reproduction equalizer A43. The detection point amplitude value of the output waveform 133 deviates from the target value.

According to the perpendicular magnetic recording / reproducing apparatus described in the first embodiment, as shown in FIG. 9, a reproduction waveform 132 and a reproduction equalization output waveform 134 outputted from the reproduction equalizer A43.
And the class I partial response method can be applied.

The class I partial response method is used in optical disk devices and the like, and details are described in Japanese Patent Laid-Open No. 2-2.
It is described in Japanese Patent No. 36823.

According to the second embodiment, since the recording equalization is performed immediately before the recording amplifier 36 without changing the recording pattern 33 itself, it is possible to freely select the encoding method and the recording current. It is possible to perform recording equalization without changing the other parts only by adding the control device 34, and it is easy to add to the conventional system.

Further, by using the perpendicular magnetic recording method described in the first embodiment, it is possible to apply the partial response method using the single layer perpendicular magnetization medium.

The single-layer perpendicular magnetic recording medium has a simpler manufacturing process than the double-layer film medium and is effective for cost reduction.

(Third Embodiment) FIG. 10 is a block diagram showing a schematic structure of a recording / reproducing apparatus which is another embodiment (third embodiment) of the present invention.

The third embodiment is an embodiment in which the magnetic recording / reproducing apparatus of the first embodiment is applied to a recording / reproducing system of a class IV partial response system.

As shown in FIG. 10, the third embodiment has the same basic configuration as that of the second embodiment, but a class IV partial response system precoder B48, a reproduction equalizer B49, and an equalizer. Demodulated data 43 using the latter signal 42
The second embodiment is different from the second embodiment in that it uses a demodulator A49 that outputs

Waveform equalization in the third embodiment will be described with reference to FIG.

As in the second embodiment, a binary rectangular wave current of ± 1 is used as the recording current, the recording current level is −1 when the recording data is 0, and the recording current level is 1 when the recording data is 1. Is set to 1.

In this case, the amplitude value of the detection point 65 of the reproduced waveform 62 corresponding to the recording data "... 101." Shown in the recording pattern 61 is changed to "...
The reproduction equalizer B49 performs equalization so as to obtain 10-1.

In the conventional magnetic recording / reproducing apparatus using the longitudinal magnetic recording method and the partial response method, the class IV partial response method is generally used, and it is very costly to use this reproducing system apparatus. It is valid.

The perpendicular magnetic recording / reproducing apparatus described in the first embodiment can form a linear system, and as in the third embodiment, by the conventional reproduction waveform equalization, the class IV partial response system is used. Can be applied.

In this case, since the response in the low frequency region is cut off, the margin for low frequency noise such as crosstalk becomes large. Particularly, since the MR head has a response to low frequency, low frequency noise is generated. It is effective in systems that cause problems.

Since the magnetic recording / reproducing apparatus described in the first embodiment can improve the linearity in the perpendicular magnetic recording system, it can be applied to other partial response systems.

Although the present invention has been specifically described based on the embodiments, it is needless to say that the present invention is not limited to the above embodiments and various modifications can be made without departing from the scope of the invention.

[0106]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

(1) In the perpendicular magnetic recording / reproducing apparatus, 2
When there is a portion where the same value continues for 2 bits or more in the binarized recording pattern, the recording current of that portion is inverted at a time interval shorter than the bit length, and the pulse-shaped reverse is performed. Since the polar magnetization is formed, it is possible to limit the maximum magnetization transition interval of the perpendicular magnetization on the magnetic recording medium and prevent the decrease of the leakage flux to the outside used for reproduction.

As a result, it is possible to prevent the deterioration of the reproduced waveform caused by the demagnetizing field in the medium of the magnetic recording medium magnetized in the vertical direction or the magnetic charge on the front and back surfaces of the medium, and to improve the linearity.

(2) The perpendicular magnetic recording / reproducing apparatus of the present invention is
In combination with the MR head, it is possible to apply a signal processing method that is premised on linearity, and thus a high density magnetic disk device can be constructed.

(3) The perpendicular magnetic recording / reproducing apparatus of the present invention is
This is particularly effective for a perpendicular magnetic recording medium that does not have a soft magnetic backing layer, which makes it possible to simplify the manufacturing process and reduce the cost.

(4) The perpendicular magnetic recording / reproducing apparatus of the present invention is
Since the recording current of the recording amplifier is controlled, the encoding method can be freely selected, and the conventional decoder can be used as it is, and the magnetization reversal can be performed without changing the encoding efficiency. It is possible to limit the interval.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a magnetic recording / reproducing apparatus that is an embodiment (Embodiment 1) of the present invention.

FIG. 2 is a diagram for describing a recording pattern recording method in the first embodiment.

FIG. 3 is a diagram showing an example of a recording current control device in FIG.

FIG. 4 is a waveform diagram showing operation waveforms of respective parts of the recording current control device shown in FIG.

5 is a diagram showing another example of pulsed current reversal in FIG.

FIG. 6 shows the relationship between the magnitude of magnetization in the pulsed magnetization reversal region and the width of pulsed current reversal and the reproduction output when the amplitude of pulsed current reversal is set to be the same as the amplitude of the recording current. It is a figure which shows the relationship with pulsed current reversal.

FIG. 7 is a block diagram showing a schematic configuration of a recording / reproducing apparatus which is another embodiment (second embodiment) of the present invention.

FIG. 8 is a schematic diagram showing a waveform after reproduction equalization in the partial response system.

FIG. 9 is a diagram for explaining the effect when the perpendicular magnetic recording / reproducing apparatus in Example 1 is applied to the class I partial response system.

FIG. 10 is a block diagram showing a schematic configuration of a recording / reproducing apparatus which is another embodiment (third embodiment) of the present invention.

FIG. 11 is a diagram showing a relationship between a recording pattern, a recording current, and a remanent magnetization perpendicular component on a magnetic recording medium in the perpendicular magnetic recording system.

FIG. 12 is a diagram for explaining an in-medium demagnetizing field in the perpendicular magnetic recording system.

FIG. 13 is a diagram for explaining a magnetic field leaking to the outside of a magnetic recording medium in a perpendicular magnetic recording system.

FIG. 14 is a recording pattern in a perpendicular magnetic recording system,
It is a figure which shows the relationship of a reproduction | regeneration waveform.

[Explanation of symbols]

1, 72 ... Recording pattern, 2, 51, 52, 91 ... Recording current, 3 ... Medium remanent magnetization vertical component, 4, 24 ... Reproduction waveform, 12 ... Leakage magnetic flux vertical component, 21 ... Recording current, 22 ...
Remanent magnetization vertical component, 23 ... Leakage magnetic flux vertical component, 25, 5
3, 54 ... Pulse current reversal, 26 ... Pulse reverse polarity magnetization, 27 ... Clock interval, 32 ... Recording encoder, 34 ...
Recording current controller, 36 ... Recording amplifier, 38 ... Recording head, 39 ... Single-layer perpendicular magnetization medium, 40 ... MR head, 41
... reproduction amplifier, 43, 49 ... reproduction equalizer, 44, 45 ...
Demodulator, 46, 48 ... Precoder, 71 ... Clock,
73 ... Edge trigger circuit, 77, 81 ... Delay circuit, 76
... Latch, 80 ... AND circuit, 75 ... Adder, 111 ...
Medium magnetization, 113 ... Medium demagnetizing field, 114 ... Magnetic transition,
115 ... Adjacent magnetization, 121 ... Medium surface magnetic charge, 122 ... Medium back surface magnetic charge.

Claims (7)

[Claims] 1. A magnetic recording medium is vertically moved by a recording current generating means for generating a recording current of opposite polarity corresponding to a binarized recording pattern, and a recording current output from the recording current generating means. In a perpendicular magnetic recording / reproducing apparatus comprising at least a recording head for magnetizing and recording the recording pattern, and a reproducing head for reproducing the recording pattern recorded on the magnetic recording medium, In the binarized recording pattern, there is provided means for detecting a portion having the same value continuously for 2 bits or more and inverting the recording current of the portion at least once at a time interval shorter than the bit length. Perpendicular magnetic recording / reproducing apparatus. 2. The perpendicular magnetic recording / reproducing apparatus according to claim 1, wherein the recording current generating means includes a recording current control device and a recording amplifier, and the recording current control device synchronizes with a clock signal. Edge trigger circuit for generating a clock pulse having a narrow pulse width, and a portion of the binarized recording pattern that continuously has the same value for two or more bits is detected and delayed for a predetermined time from the clock pulse. The recording amplifier includes first means for generating an equalized pulse having a narrow pulse width, and means for generating an output pulse by adding the clock pulse and the equalized pulse, A perpendicular magnetic recording / reproducing apparatus, which generates a recording current that is inverted for each output pulse that is output. 3. The perpendicular magnetic recording / reproducing apparatus according to claim 2, wherein the first means of the recording current control device is binarized with a first delay circuit that delays the clock pulse for a predetermined time. A second delay circuit for delaying the recorded pattern by 1 bit,
A matching circuit that matches the binarized recording pattern with the 1-bit delayed recording pattern output from the second delay circuit, the output of the matching circuit, and the output from the first delay circuit. A perpendicular magnetic recording / reproducing apparatus comprising: a logical product circuit that takes a logical product of a clock pulse delayed by a predetermined time to generate an equalized pulse having a narrow pulse width. 4. The perpendicular magnetic recording / reproducing apparatus according to claim 1, wherein the reproducing head is a reproducing head using a magnetoresistive effect. Playback device. 5. The perpendicular magnetic recording / reproducing apparatus according to claim 1, wherein a magnetic recording medium having no soft magnetic backing layer is used as the magnetic recording medium. Perpendicular magnetic recording / reproducing device. 6. The perpendicular magnetic recording / reproducing apparatus according to claim 1, wherein a recording encoder for encoding input data is provided in a stage preceding the recording current controller, and the reproducing head. A perpendicular magnetic recording / reproducing apparatus comprising: a demodulator that outputs demodulated data in a subsequent stage. 7. The perpendicular magnetic recording / reproducing apparatus according to claim 6, further comprising a precoder between the recording encoder and the recording current controller, and a reproducing equalizer between the demodulator and the reproducing head. A perpendicular magnetic recording / reproducing apparatus comprising: