JPH0554309A - Magnetic recorder - Google Patents

Abstract

PURPOSE:To prevent the generation of a zero-cross error at the reproduction even when a head which records the resolution too high is used in the magnetic recorder. CONSTITUTION:Writing data WD becomes a delay signal 22b in an AND gate 21 and in a delay circuit 22, and a transistor 24 is turned on and off by a signal converted by an inverter 23, turning on and off the current flowing through resistance 25 and controlling current 27 in a writing current setting terminal 4. By the operation of this and a delay circuit 28, a current deterioration area 3a, is generated at the change of the writing current 3a. Thus, the recording is performed by reducing not the reproduction output but the resolution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for recording information by magnetizing a recording medium.

[0002]

2. Description of the Related Art FIGS. 5 and 6 are views showing a conventional magnetic recording apparatus. FIG. 5A is a block diagram of a recording / reproducing system, and FIGS. It is a signal waveform diagram.

In the figure, 1 is a recording / reproducing head, 2 is a writing / reading integrated circuit in which a recording / reproducing system is housed in a package, 3 is connected to the recording / reproducing head 1, and a write current 3a is passed, and a reproducing signal is supplied. A recording / reproducing amplifier that amplifies and outputs a read voltage 3b, 4 is a write current 3a
A write current setting terminal for setting the value of 5 and a write data input terminal for inputting write data WD, and an output 6a for inputting write data WD and forming a waveform of write current 3a.
Is a frequency dividing circuit for sending to the recording / reproducing amplifier 3.

7 removes noise from the read voltage 3b,
Further, a filter differentiator which outputs a signal 7a obtained by differentiating this, 8 is a zero-cross comparator which outputs an output 8a in which a zero-cross point is clarified from the differentiated signal 7a, and 9 is read data RD from rising and falling edges of the comparator output 8a. Pulse shaping circuit 10, read data RD
And a read data output terminal 11 for outputting the disk residual magnetism recorded on the medium.

The conventional magnetic recording device is constructed as described above and operates as follows. First, the write data WD input from the interface (not shown) is frequency-divided by the frequency dividing circuit 6 and becomes the output 6a. Based on this, the write current 3a is applied to the recording / reproducing head 1 at the current value set in the write current setting terminal 4. This write current 3a
Recording is performed by the method described above, and the state of being magnetized on the medium becomes the residual magnetic field 11 of the disk.

A read voltage 3b is obtained by reading the disk residual magnetism 11 by the recording / reproducing head 1 and amplifying it by the recording / reproducing amplifier 3. A differentiator 7 differentiates this to become a differentiator output 7a. The output 7a is detected by the zero-cross comparator 8 to detect the peak of the read voltage 3b and becomes the output 8a. The edge of the output 8a is pulsed by the pulse shaping circuit 9 and output to the interface as read data RD.

FIG. 6 shows the signals of the respective write / read sections when recorded by a magnetic recording apparatus having a high resolution.
The waveform of the read voltage 3b becomes steep and the differential signal 7a
A deep saddle portion 7a1 appears in the waveform of. This phenomenon is called the shouldering effect.

[0008]

In the conventional magnetic recording apparatus as described above, since the zero cross point is determined by the differential signal 7a of the read voltage 3b read by the recording / reproducing head 1, high resolution is recorded. Then, Fig. 6 (D)
As shown in FIG. 5, when a deep saddle portion 7a1 is generated in the differential signal 7a and noise is added to this, the zero cross easily occurs. When the differential signal 7a crosses zero, there is a problem that a zero cross error occurs in which an erroneous pulse is formed.

In a magnetic recording device, a recording device and a reproducing device may be different. Therefore, when the frequency band which is recorded with high resolution by the writing device and shows the differential characteristic of the differentiator 7 of the reproducing device is wide in the high range, the saddle portion 7a _{1 of the} differential signal 7a becomes wide and deep, and the read voltage 3b It is easy to make a zero cross at the shoulder position. In addition, due to the influence of medium noise, device noise, etc., zero crossing occurs and an erroneous pulse is formed, which significantly deteriorates the reliability of the magnetic recording device.

Therefore, for example, Japanese Patent Application Laid-Open No. 56-3420 discloses that a circuit for preventing zero-cross at the time of reading is provided as a measure against the above-mentioned problem. However, the purpose of this is to read the written medium without zero cross error, and generally, there are many reproducing apparatuses on the market which do not have such a function. Therefore, no error occurs when read with a playback device with the above functions,
As mentioned above, the error when reading with a different playback device,
After all it cannot be compensated.

The present invention has been made to solve the above-mentioned problems, and even if a recording / reproducing head having a narrow head gap for recording with high resolution is used, it is possible to prevent the occurrence of a zero-cross error during reproduction. It is an object of the present invention to provide a magnetic recording device of this kind.

[0012]

According to a first aspect of the present invention, there is provided a magnetic recording apparatus, wherein when a write current changes, a current value input to a write current setting terminal is lowered for a first predetermined time. It was done.

Further, the magnetic recording apparatus according to the second aspect of the present invention is such that, when the write current changes, the current value input to the write current setting terminal is set to zero for the second predetermined time.

[0014]

In the first aspect of the present invention, the current value is lowered for the first predetermined time when the write current changes, and in the second aspect, the current value is set to zero for the second predetermined time. Alternatively, there is a non-magnetized region, and there are three or two places where the magnetization changes (one place in the conventional device), and solitary waves are generated three or two times during reproduction. Therefore, the full width at half maximum of the solitary waves synthesized by overlapping these solitary waves is equivalently widened.

[0015]

【Example】

Example 1. 1 and 2 are views showing an embodiment of the first invention of the present invention, FIG. 1 (A) is a write current compensation circuit diagram,
FIG. 1 (B) is a signal waveform diagram of each part of writing, and FIG.
It is a signal waveform diagram of each part for reading, and the same parts as those of the conventional device are denoted by the same reference numerals. Note that FIG. 5A is also used in this embodiment.

In the figure, 21 is an AND gate, 22 is a delay circuit comprising a capacitor C and a resistor R for setting a second predetermined time, 22a is a charge / discharge signal, 22b is a delay signal, 23 is an inverter, and 23a is 23a. Its output signal, 24
Is a write current setting transistor, 25 is a write current setting resistor, 26 is a write compensation current setting resistor, 27 is a current flowing into the write current setting terminal 4, 28 is a first predetermined timing of the pulse of the write data WD. It is a delay circuit for shifting the time.

Next, the operation of this embodiment will be described. First,
The write data WD input from the interface is delayed by the delay circuit 28 and then frequency-divided by the frequency dividing circuit 6 in order to match the compensation timing, and becomes the output 6a. Based on this, the write current 3a is applied to the recording / reproducing head 1 at the current value set in the current setting terminal 4.

At this time, the write data WD is input to the AND gate 21, converted into the delay signal 22b which becomes "L" for the second predetermined time set by the charge / discharge signal 22a of the delay circuit 22, and the inverter 23. Entered in.
The output signal 23a of the inverter 23 is input to the write current setting transistor 24. The collector of the transistor 24 is connected to the write current setting terminal 4. A current proportional to the current 27 flowing into the setting terminal 4 is supplied to the recording / reproducing head 1 as the write current 3a.

Therefore, the transistor 24 is turned off for the second predetermined time set by the delay circuit 22 after the write data WD is input to the AND gate 21,
A current set by the write compensation current setting resistor 26 flows as the write current 3a. In other states, the transistor 24 is turned on and the write current 3a set by the resistors 25 and 26 flows. Therefore, the write current 3
When the value of a changes, the region 3a _{1 in} which the current decreases for the first predetermined time occurs.

Recording is performed by the write current 3a shown in FIG. 2 (A), and the disk residual magnetism 11 shown in FIG. 2 (B) is obtained from the state magnetized on the medium. This is read by the recording / reproducing head 1 and amplified by the recording / reproducing amplifier 3 to obtain the read voltage 3b shown in FIG. 2 (C). When the magnetization information recorded on the medium changes, there is a region 11a where the magnetization is lowered, so that there are three places where the magnetization changes (one where there is no region 11a), and during reproduction, FIG. As shown in, the solitary wave is generated three times.
Therefore, when these three solitary waves are overlapped, the half-value width of the synthesized solitary waves is equivalently widened to a shape,
The resolution is reduced.

Further, since the inclination of the change in magnetization is the same as the inclination during normal recording, the output of the reproduced wave does not decrease. The read voltage 3b differentiated by the differentiator 7 is shown in FIG.
The differential signal 7a shown in (D) is obtained. The differential signal 7a is less likely to be zero-crossed because the shoulder inclination becomes steeper because the half-value width of the read voltage 3b is increased and the resolution is lowered. In addition, since the half-value width is widened, the peak of the differential signal 7a shifts in the direction in which the width W of the saddle portion 7a ₁ is narrowed, so that almost no zero cross occurs.
The peak of the differential signal 7a is detected by the zero-cross comparator 8, the pulse is shaped by the pulse shaping circuit 9, and the read signal RD is output to the interface.

Example 2. 3 and 4 show a second embodiment of the present invention.
FIG. 3A is a write compensation circuit diagram, FIG. 3B is a signal waveform diagram of each writing portion, and FIG. 4 is a signal waveform diagram of each writing / reading portion.

FIG. 3 is obtained by removing the write compensation current setting resistor 26 and the delay circuit 28 from FIG. 1 (A).
Since the operation is almost the same as that of the first embodiment, detailed description will be omitted. In the write current 3a of this embodiment, the region 3a ₂ that changes to zero for the second predetermined time is generated. Therefore, as shown in FIG. 4, when the magnetization information recorded on the medium changes, there are two places where the magnetization changes, and a solitary wave is generated twice during reproduction. This is the same as the first embodiment.

[0024]

As described above, according to the first invention of the present invention, the current value is decreased for the first predetermined time when the write current is changed, and in the second invention, the second predetermined time is set to zero. By using a weakly magnetized area or a non-magnetized area in the medium, even if a recording / reproducing head that records with high resolution is used, the resolution is lowered without reducing the reproduction output and recording is performed, and the occurrence of a zero-cross error occurs. It is effective in preventing and improving reliability.

[Brief description of drawings]

1A and 1B are views showing a first embodiment of the present invention, in which FIG. 1A is a write compensation circuit diagram and FIG. 1B is a signal waveform diagram of write portions.

FIG. 2 is a signal waveform diagram of write / read units according to the first embodiment of the present invention.

3A and 3B are views showing a second embodiment of the present invention, in which FIG. 3A is a write compensation circuit diagram, and FIG. 3B is a signal waveform diagram of write portions.

FIG. 4 is a signal waveform diagram of write / read units according to a second embodiment of the present invention.

5A and 5B are diagrams showing a conventional magnetic recording device, in which FIG. 5A is a block diagram of a recording / reproducing system, and FIG. 5B is a signal waveform diagram of write / read portions.

FIG. 6 is a signal waveform diagram of write / read portions of a conventional magnetic recording device.

[Explanation of symbols]

1 recording / reproducing head 3 recording / reproducing amplifier 3a writing current 3a ₁ writing current lowering area 3a ₂ writing current zero area 4 writing current setting terminal 6 frequency dividing circuit 7 filter differentiator 8 zero cross comparator 9 pulse shaping circuit 11 disk remanence 21 AND gate 22 Second predetermined time setting delay circuit 23 Inverter 24 Write current setting transistor 25 Write current setting resistor 26 Write compensation current setting resistor 28 First predetermined time setting delay circuit

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 13, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (2)

[Claims] 1. A device for magnetizing a medium by causing a write current determined by a current value input to a write current setting terminal to flow through a head, wherein the current value input to the setting terminal is changed when the write current changes. A magnetic recording device comprising a current compensating circuit for lowering a predetermined time. 2. A device for magnetizing a medium by causing a write current, which is determined by a current value input to a write current setting terminal, to flow through a head, wherein the current value input to the setting terminal when the write current changes is a second value. 2. A magnetic recording device comprising a current compensation circuit for zeroing a predetermined time.