JPH0447518A - Position detecting method - Google Patents

Abstract

PURPOSE:To reduce a production cost by simplifying a circuit and reducing a circuit scale by detecting the positional deviation of a magnetic head from the time interval of a pulse representing position information on the magnetic head. CONSTITUTION:When a reference magnetizing area 8, a first magnetizing area 9, and a second magnetizing area 10 for a servo signal recorded on a magnetic recording medium 1 are interlinked with the magnetic head 2, a signal voltage read out with the magnetic head 2 is integrated at an integration circuit 4, and a rectangular wave is outputted. A zero cross detector 5 outputs a pulse wave when the rectangular pulse goes to 0V, and a timer 6 measures a first time required until a first pulse is outputted after the final pulse of a reference signal is outputted, and a second time required until a following pulse is outputted after the first pulse of a position signal is outputted. A microcomputer 7 performs prescribed calculation processing, and finds how much the direction of the magnetic head 2 is deviated. In such a manner, a method can be realized with a simple and small scale circuit, and a manufacturing cross can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic storage device that controls the position of a magnetic head, and more particularly to a method of detecting a misaligned position of a magnetic head.

[Prior Art] FIG. 5 is a block diagram showing a conventional magnetic recording device described in, for example, "Electric Servo Design Manual 1 (1978, published by Trikebbs Co., Ltd.), Chapter 15, Page 12. .In this Figure 5, (1) is a magnetic recording medium;
(2) is a magnetic head that reads the positional information recorded on this magnetic recording medium, (3) is an amplifier that amplifies the positional information read by this magnetic head, and (51) is from the amplifier (3). (52) is an even signal detection/holding circuit that detects and holds an even signal from the output signal; (52) is an odd signal detection/hold circuit that detects and holds an odd signal from the signal output from the amplifier (3); (53) is the even signal output from the even signal detection/holding circuit (51);
A differential amplifier (54) that detects and holds the difference between the odd signal and the odd signal output from the odd signal/detection/hold circuit (52).
(7) is an A/D converter that converts the analog signal output from the differential amplifier into a digital signal and outputs the digital signal;
is a microcomputer and has an A/D converter (5
The position of the magnetic head on the magnetic recording medium (1) is detected by subjecting the digital signal output from 4) to a predetermined process.

FIG. 6 is a diagram showing an example of a position signal recorded on the magnetic recording medium (1). (55) is the magnetization reversal corresponding to the above even number signal, (56) is the magnetization reversal corresponding to the above odd number signal 5 (A) is the state where the magnetic head (2) is accurately following the track, (B) is a state in which the magnetic head (2) is off track to the right in the direction of movement,
(C) shows a state in which the magnetic head (2) is off track to the left in its moving direction.

FIG. 7 is an exemplary diagram of a position signal read out by the magnetic head (2). In FIG. 7, (A) is a read signal when the magnetic head (2) is accurately on the track on the magnetic storage medium (1), and (B) and (C) are the read signals when the magnetic head (2) is accurately on the track on the magnetic storage medium (1). 2) is a read signal when the signal is off the track on the magnetic recording medium (1), and (57
) is an even signal, and (58) is an odd signal.

Next, a method for detecting the position of the magnetic head on the magnetic recording medium (1) in the conventional magnetic recording apparatus configured as described above will be described.

When the magnetic head (2) accurately follows the track on the magnetic medium as shown by position M (A) in FIG. 6, the level of the signal read by this magnetic head is as shown in FIG. 7 (A). ), the even signal L IIV@11 and the odd signal L IIV@11 are equal, and the differential amplifier (53
) output becomes OV.

When the magnetic head (2) is at position f(B) or (
When the magnetic recording medium is off track as shown in Fig. 7 (B) or (C), the level of the signal read by the magnetic head (2) will be as shown in Fig. 7 (B) or (C). , an even signal L avmh and an odd signal. , 6, the difference is output from the differential amplifier (53). At this time, the amount of deviation of the magnetic head (2) from the track is proportional to the level difference between the even signal L even and the odd signal 64, and the direction of the deviation (right or left with respect to the track) ) is uniquely determined by the sign of the level difference, so the output signal of the differential amplifier (53) is used as a signal representing the position of the magnetic head (2) on the track. The level difference output from the differential amplifier (53) is converted from an analog signal to a digital signal by an A/D converter (54), and then sent to the microcomputer (7).
A predetermined process is performed.

[Problem to be solved by the invention] In the conventional position detection method, the even number signal detection/holding circuit and the odd number signal detection/holding circuit are complicated and large in scale, so there was a problem that production costs were high. .

This invention was made to solve these problems, and aims to provide a position detection method that can simplify the circuit, reduce the scale, and lower production costs. .

[Means for Solving the Problems] A position detection method according to the present invention provides a magnetic recording medium having a magnetized area defined by four predetermined points representing position information: a magnetic head for reading signals; an integrating means for integrating the read position information; a detecting means for outputting a pulse indicating when the integrated position information reaches a predetermined potential; a time period of the pulse; The apparatus is equipped with a measuring means for measuring the interval; and a calculating means for performing calculation processing based on the above-mentioned time and calculating the position of deviation of the magnetic head from the track from the result.

[Operations] In this invention, the amount of deviation of the magnetic head from the track is determined from the time interval of the pulses.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the magnetic storage device of the present invention. In this Figure 1, (1) to 3)
and (7) are the same as those shown in the conventional example of FIG. 5, so their explanation will be omitted here. (4) is an integrating means, which is an integrating circuit that integrates the signal output from the amplifier (3); and (5) is a detecting means, which generates a pulse when the integrated signal reaches Ov, for example. The zero-cross detector (6) is a measuring means, and is a timer that measures the time interval of the pulses output from the zero-cross detector (5).

FIG. 2 is a diagram showing servo signals recorded on the magnetic recording medium (1). In this Figure 2, (8) is a reference magnetization region that generates a reference signal that serves as a time reference, and is made up of continuous magnetization reversals, and (9) is a first magnetization region that has position information. The region (10) that is magnetized in one direction is a second magnetized region that has position information and generates a position signal, and the first magnetized region (9)
The first magnetized region (9) is magnetized in a direction opposite to that of the first magnetized region (9). The track width is Tw,
The last magnetization reversal (8a) of the reference magnetization region (8) and the first magnetization reversal (9) constituting the second magnetization region (9).
a), and furthermore, the first magnetization reversal (9a) and the subsequent magnetization reversal (9b) constituting the second magnetization region (9).
If the distance from
, -T, ). (A) shows the state in which the magnetic head (2) is accurately positioned on the track on the magnetic recording medium (1).
(B) shows a state in which the magnetic head (2) is deviated downward by Δd from the track on the magnetic recording medium (1); (C)
is a state in which the magnetic head (2) is deviated upward by Δd from the track on the magnetic recording medium (1).

FIG. 3 is a waveform example diagram showing the reference signal and position signal output from the integrating circuit (4). The integrating circuit (4) is configured so that the intermediate potential of the rectangular wave on the left side of the figure is 0■.

FIG. 4 shows a pulse output from the zero cross detector (6), and this pulse is output when the potential corresponding to the output waveform from the integrating circuit (4) becomes OV.

Next, a method for detecting the position of the magnetic head of the magnetic storage device configured as shown in FIG. 1 will be described with reference to FIGS. 2 to 4 as appropriate.

According to the law of electromagnetic induction, the signal voltage read by the magnetic head (2) is a value dΦ/dt obtained by differentiating the magnetic flux Φ interlinking with the magnetic head (2) with respect to the moving time t of the magnetic head. Therefore, when the reference magnetization region (8), first magnetization region (9), and second magnetization region (10) shown in FIG. The signal voltage is integrated by an integrating circuit (4), and the integrating circuit (4) outputs a waveform as shown in FIG. Then, the zero-cross detector (5) outputs a pulse wave when this rectangular wave reaches 0■, as shown in FIG. The timer (6) measures the first time required from the output of the last pulse of the reference signal until the first pulse of the position signal is output, and the first time required from the output of the first pulse of the position signal to the output of the first pulse of the position signal. A second time required until the pulse is output is measured. In other words, this first time is when the magnetic head (2) is in the reference magnetized area (8) on the magnetic storage medium (1).
The second time is the time required for the magnetic head (2) to move by the distance d0 from the last magnetization reversal (8a) to the first magnetization reversal (9a) of the second magnetization region. This is the time required to move the distance d+ from the first magnetization reversal (9a) to the subsequent magnetization reversal (9b) of the magnetization region No. 2.

By the way, the first and second times are determined from a relational expression as described below.

When the magnetic head (2) is completely on an even track as shown in position (A) in FIG.
) is as shown in FIG. 3(A), and the zero-cross detector (5) outputs a pulse as shown in FIG. 4(A). If the relative speed between the magnetic head (2) and the magnetic recording medium (1) is V, then the first time T0 and the second time t0 are respectively To = do /v・−(1) to It can be expressed as ==d+/V---(2>).

When the magnetic head (2) deviates downward from the even track by Δd as shown in position (B) in FIG. 2, the output waveform of the integrating circuit (4) becomes as shown in FIG. 3 (B), The zero cross detector (5) outputs a pulse as shown in FIG. 4(B).

At this time, the first time TI and the second time 1+ are respectively T, ='r, +(dt/'rw) - (Δd
/v)...(3) t+ =to-(at/'r, )-(Δd/
v )...(4) It can be expressed as follows.

When the magnetic head (2) deviates upward from the even track by Δd as shown in position (C) in FIG. 2, the output waveform of the integrating circuit (4) becomes as shown in FIG. 3 (C). The zero cross detector (5) outputs a pulse as shown in FIG. 4(B).

At this time, the first time T2 and the second time t2 are respectively T,='ro...(5) tz=t0(at/"'r,)・(Δd/
v )...(6) It can be expressed as follows.

When the magnetic head (2) is completely on an odd-numbered track as shown in position (D) in FIG.
) is as shown in FIG. 3(D), and the zero-cross detector (5) outputs a pulse as shown in FIG. 4(D). At this time, the first time T and the second time t
, can be respectively expressed as: T 3 −T o (7) tz=to (8).

When the magnetic head (2) deviates downward from the odd-numbered track by Δd as shown in position (E) in FIG. 2, the output waveform of the integrating circuit (4) becomes as shown in FIG. 3 (E), The zero cross detector (5) outputs a pulse wave as shown in FIG. 4(E).

At this time, the first time T4 and the second time t4 are respectively T4=TO...(9) t4=<dt/'r,)-(Δd/v)...
(10) It can be expressed as:

When the magnetic head (2) deviates upward from the odd-numbered track by Δd as shown in position (F) in FIG. 2, the output waveform of the integrating circuit (4) becomes as shown in FIG. 3 (F), The zero cross detector (5) outputs a pulse as shown in FIG. 4(F).

At this time, the first time T5 and the second time t5 are each T s = T o + t.

(d, /T,)・(Δd/v)...(11) ts=(at/T,)-(Δd/v)...
(12) It can be expressed as:

The microcomputer (7) has the above-mentioned relational expression (1)
A predetermined calculation process is performed based on (12) to determine in which direction and by how much the magnetic head (2) is deviated.

In the manner described above, the position of the magnetic head relative to the track can be detected.

In the above embodiment, integration and zero-cross detection are performed by an integrating circuit and a zero-cross detector, respectively, but it goes without saying that similar effects can be achieved even if these integration and zero-cross detection are processed by software.

U Effect of the Invention 7 As explained above in detail, the present invention detects the positional deviation of the magnetic head from the time interval of pulses representing positional information on the magnetic head, so it is possible to extremely easily and accurately determine the position of the magnetic head. In addition, the integration circuit can detect
Since it is realized with an extremely simple and small-scale circuit consisting only of a zero-cross detector and a timer, it has the effect of keeping manufacturing costs low.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a diagram of a magnetic recording medium on which position information is recorded in the above embodiment, and FIGS. 3 and 4 are operations of the above embodiment. FIG. 5 is a block diagram showing a conventional example. FIG. 6 is a diagram of a magnetic recording medium on which position information is recorded in the conventional example. FIG. 7 explains the operation of the conventional example. This is a diagram for In the figure, (1) is a magnetic recording medium, (2) is a magnetic head, (4) is an integrating circuit, (5) is a zero cross detector, (6) is a timer, (7) is a microcomputer, (9) is the first magnetization region, and (10) is the second magnetization region. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] In a position detection method for controlling the misaligned position of a magnetic head using position information recorded on a magnetic recording medium; A magnetized region exists, and position information is represented by a second magnetized region that is magnetized in the opposite direction to the first magnetized region, and this second magnetized region is surrounded by four predetermined points. The signal corresponding to the above position information is read out by the magnetic head, integrated, and then a pulse indicating this is output when it reaches a predetermined potential; The time of the above output pulse The interval is measured and calculated,
A position detection method characterized in that the position of deviation of the magnetic head from the track is determined from the result of this calculation process.