JPH03280275A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To expand the detection range of an off-track and to attain accurate positioning control by constituting position data of burst patterns of two phases or more and recording respective burst and on the same periphery as track identification(ID) information. CONSTITUTION:A reading signal from a magnetic head 32 is inputted to a servo detecting circuit 34 through a read amplifier 33 and the circuit 34 detects the position data 22 of servo information from the inputted signal. The data 22 include the burst data of three phases A to C and each phase repeats burst data corresponding to two tracks from a track center and an erase data for one track. Thereby, the same pattern appears in every three tracks. A CPU 36 obtains the data 22 through an A/S converter 35 and executes the position control of the head 32 by setting up a point on which a difference between the burst signals of two phases is '0' as a center position. Namely, the CPU 36 applies a correction signal to a driving circuit 38 through a D/A converter 37 and drives a VCM 39 to position the head 32 on the center of an objective track.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a data surface servo type magnetic recording and reproducing device.

(Prior Art) Conventionally, data is recorded/recorded on a recording medium using a magnetic head.
In hard disk drives that perform playback, there is a data surface servo system that controls the positioning of a magnetic head without having a dedicated servo surface. This data surface servo method is also called an embedded servo method, and is roughly divided into a sector servo method and an index method. Normally, servo information consists of track identification information and position data, and is recorded in advance on a data surface. The track identification information is track-specific address information and is used for rough positioning. The position data is position information for detecting the position of the magnetic head, and is used for precise positioning.

In a hard disk drive using servo information with such a configuration, control is performed to first seek the magnetic head to a target track based on track identification information, and then position the magnetic head to the center position of the target track based on position data. It will be done.

FIG. 4 is a diagram showing a conventional servo information recording state. Servo information consisting of track identification information 11 and position data 12 is recorded on the recording medium (data surface) for each sector. Here, as the position data 12, two-phase burst data indicated by A and B is used. Burst data A and B are alternately recorded at positions shifted by 1/2 track from the normal track position. During the position control mode in which the magnetic head is positioned at the center position of the target track, the burst data A,
The amount of off-track is detected from the phase difference of B, and the amount of deviation is corrected.

That is, in FIG. 4, for example, the magnetic head 13 is
When positioning at the center position of the track, n+
If it is shifted by one track direction (X direction in the figure), rA-
The BJ level becomes lower than the on-track state as shown in FIG. Therefore, in this case, rA-BJ
-rOJ by moving the magnetic head 13 in the outer circumferential direction to correct the deviation. Conversely, if it deviates in the n-1 track direction (Y direction in the figure), rA-BJ
Since the level of becomes high, the magnetic head 13 is moved in the inner circumferential direction so that rA-BJ-rOJ, and the deviation is corrected.

(Problem to be Solved by the Invention) By the way, in the above configuration, rA-B is
J -rOJ, so the off-track detection range is ±
It is one track. Therefore, if the head misalignment occurs beyond this detection range, it cannot be corrected. In addition, conventionally, when writing servo information, it is necessary to write track identification information and position data over 1/2 track, which takes time.

The present invention has been made in view of the above points, and is a magnetic recording and reproducing method that can expand the off-track detection range, perform more accurate positioning control, and shorten the servo write time in the data surface servo method. The purpose is to provide equipment.

[Configuration of the Invention (Means and Effects for Solving the Problems) That is, the present invention provides a data surface servo type magnetic recording medium in which servo information consisting of track identification information and position data having at least three phases or more of burst data is recorded. The recording and reproducing apparatus records each of the burst data constituting the position data on the same circumference as the track identification information.

According to such a configuration, the off-track detection range is widened, and the positioning of the magnetic head can be controlled with high precision. Further, since it is not necessary to write the track identification information and position data by shifting 1/2 track as in the conventional method, the servo write time can be shortened.

(Embodiment) Hereinafter, a magnetic recording and reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a servo recording state in, for example, a sector servo type hard disk device.

In FIG. 1, servo information consisting of track identification information 21 and position data 22 is recorded for each sector on a recording medium (data surface).

The track identification information 21 is unique information for each track, and is recorded at a position shifted by 172 tracks from the center position of the normal track (the center position of the normal data recording area). The position data 22 is data for positioning the magnetic head 23 at the center position of the track, and is composed of three-phase burst data indicated by A, B, and C. Here, in the same embodiment, the burst data A
, B, and C are each recorded on the same circumference as the track identification information 21.

FIG. 2 is a block diagram showing the circuit configuration of the same embodiment.

The magnetic head 32 seeks in the radial direction of the recording medium 31 to record/reproduce data. The lead amplifier 33 is
The read signal of the magnetic head 32 is amplified. The servo detection circuit 34 individually samples and holds the track identification information 21 and position data 22 in the read signal of the magnetic head 32. The A/D converter 35 is connected to the servo detection circuit 3
The track identification information 21 and position data 22 detected by 4 are digitized and output to CPU'B.

The CPU 3B is in charge of overall head positioning control based on servo information, and here position data 2
2, a correction signal for correcting the off-track of the magnetic head 32 is output.

The D/A converter 37 converts the digital correction signal from the CPU 3B into an analog signal. VCM drive circuit 38
is the VCM based on the correction signal from the D/A converter 37.
(Voice coil motor) 39 is supplied with driving current.

VCM 39 is a motor for driving carriage 40. The carriage 40 is equipped with a magnetic head 32,
This magnetic head 32 is caused to seek in the radial direction of the recording medium 31.

Next, the operation of this embodiment will be explained.

Here, we will explain the operation after moving the magnetic head 32 to the target track based on the track identification information 21 shown in FIG. 1, that is, the operation in the position control mode to position the magnetic head 32 at the center position of the target track. do.

A read signal from the magnetic head 32 is given to a servo detection circuit 34 via a read amplifier 33. The servo detection circuit 34 detects position data 22, which is servo information, from this read signal. As shown in FIG. 1, the position data 22 is A, B.

It has three phases of burst data of C, and for each phase, burst data for two tracks and erase for one track are repeated from the track center. As a result, the same data pattern appears every three tracks.

If the width of the magnetic head 32 is the same as the track width, AS
The output waveforms of each phase of B and C are as shown in FIG.

Here, by obtaining the position data 22 through the A/D converter 35, the CPU 3B executes position control of the magnetic head 32 with the point where the difference between the two-phase burst data is rOJ as the center position (track center). . That is, for example, when positioning the magnetic head 32 at the center position of the n track, the CPU'S determines that the phase of rC-AJ is "o".
” A correction signal is output so that This correction signal is
The signal is applied to the VCM drive circuit 38 via the D/A converter 37.

The VCM drive circuit 38 controls the VCM based on this correction signal.
Drive 39. As a result, the magnetic head 32 is positioned at the center of the target track via the carriage 40.

In this case, for example, if the magnetic head 32 is misaligned in the n+1 track direction (arrow X direction), then rC-Aj is "0".
'' is between the n+1 track and the n+2 track. On the other hand, if the magnetic head 32 is displaced in the n-1) rack direction (arrow Y direction), the next time rC-AJ becomes "0" is between the n-1 track and the n-2 track. In this way, rC-AJ-r at 1.5 track intervals
Becoming an O.J. Therefore, head misalignment can be corrected within an off-track detection range of ±1.5 tracks. Similarly, the CPU 3B performs position control using, for example, the phase of rA-BJ to control the position of the n+1 track, and the phase of rB-CJ to control the position of the n+2 track. In this case as well, the off-track detection range is ±1.5 tracks.

In this way, the position data 22 consisting of three-phase burst data allows the magnetic head 32 to be positioned at the center of the target track within the off-track detection range of ±1.5 tracks. Therefore, positioning control of the magnetic head 32 can be performed with higher precision than in the past. In addition, as shown in FIG. 1, by recording each of the burst data constituting the position data 22 on the same circumference as the track identification information 21, the track identification information is shifted by 1/2 track as in the conventional method. Information 21
There is no need to write the position data 22. This allows the servo write time to be shortened.

In addition, in the same embodiment, the track position is 1/2 of the normal track position.
Although the track identification information 21 is recorded at a shifted position, it can be recorded at a normal track position if the position data 22 is composed of burst data of three or more phases.

[Effects of the Invention] As described above, according to the present invention, in the data surface servo system, the position data is composed of a burst pattern of three or more phases, and each of the burst data is arranged on the same circumference as the track identification information. By recording, the off-track detection range can be expanded and more accurate positioning control can be executed.

Further, since track identification information and position data can be easily written without shifting by 1/2 track, the servo write time can be shortened.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a servo information recording state according to an embodiment of the present invention, Fig. 2 is a block diagram showing the circuit configuration of a control system of the embodiment, and Fig. 3 explains the operation of the embodiment. FIG. 4 is a diagram showing a conventional servo information recording state, and FIG. 5 is a signal waveform diagram for explaining the conventional operation. 21... Track identification information, 22... Position data, 81... Recording medium, 32... Magnetic head, 3
3... Lead amplifier, 34... Servo detection circuit, 3
5...A/D converter, 8B-CPU, 37-D
/ A converter, 3B-V CM drive circuit, 39...
VCM, 40...carriage.

Claims (1)

[Scope of Claims] A data surface servo type magnetic recording and reproducing device that records servo information consisting of track identification information and position data having at least three phases or more of burst data, wherein each of the above-mentioned bursts forming the above-mentioned position data is recorded. A magnetic recording/reproducing device characterized in that each piece of data is recorded on the same circumference as the track identification information.