JPS58220280A - Measuring method of magnetic head tracking - Google Patents

Abstract

PURPOSE:To measure easily a shift degree of a magnetic head, by recording previously a data shifted by a prescribed degree from a reference position to a recording medium and then giving an operation to an output signal obtained by reproducing a master data. CONSTITUTION:Four data 3 are recorded on a master tape 1 at positions shifted by distances +a, +b, -a and -b respectively along a reference line 2. Therefore a magnetic head 4 obtains a reproduced output having a gap width equivalent just to the scanned width on the data 3. Then the reproduced signal amplified by an amplifier 8 of a device 31 to be measured is fed to a measuring device 30, and a microcomputer 11 obtains the difference of reproduced output signals to give an operation to a shift degree from the center. The result of this operation is stored in a memory 12, and at the same time delivers an output to a display 14 or a printer 13. In such a way, a tracking shift degree of the head 4 can be measured automatically and in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention The present invention relates to a method for measuring magnetic head tracking.
A magnetic head tracking measurement method for measuring the relative position between the magnetic head and recording medium (magnetic tape, magnetic disk) of a magnetic recording device (magnetic tape storage device, fixed head magnetic disk storage device) in which the magnetic head is fixed to the It depends.

Prior Art As a conventional tracking measurement method, a method has been proposed in which, for example, in a magnetic tape device, a magnetic head writes predetermined magnetic information on a magnetic tape, the magnetic tape is developed with iron powder to develop the magnetized portion, and the measurement is performed using a microscope or the like. ing. However, this method has problems in that measurement accuracy is unstable due to the size of the iron powder, resolution of the microscope, etc., and measurement requires a long time.

OBJECT OF THE INVENTION The purpose of the present invention is to eliminate the problems of the prior art, and to make it possible to measure the tracking of a magnetic head by reproducing a master tape on which predetermined magnetic information is stored in advance. A method for measuring magnetic head tracking is provided.

It is.

Comprehensive invention of invention A reef air head tracking treasure measuring knife according to the present invention.

The value is a position that is shifted by a predetermined distance from the planned reference position.

Prepare a recording medium on which multiple pieces of recorded information are recorded,
a first step in which a fixed magnetic head reads out the recording medium; and a first step in which the recording medium is read by the first step.

It includes a second step of comparing the plural pieces of output information found, and a sixth step of obtaining the deviation direction and deviation I by performing a predetermined calculation according to the comparison result in the second step. It is characterized by

Z, D 1 example 　 　 　 　 　 ゛.

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

FIG. 1 is a diagram for explaining recorded information on a master tape according to the present invention. In the figure, KfX reference ff82 K on Master 5-P1 "C+ a *
+ +6 s +α.

- Four pieces of data 6 are written at positions shifted by distance A.

recorded. The length of this data 6 is the length of the magnetic head 4.
is long enough to measure its playback output,
Furthermore, in order to eliminate the influence of harmonics, this data 6
It is set to the reference frequency used by the device under test (magnetic tape storage device).

The magnetic head 4 has a gap width of 7 as shown in FIG.
obtains a reproduction output corresponding to the width scanned on data 5. Second
In the case of Figure (a), the effective width of the reproduced output is (L-1). When the magnetic head 4 scans the master tape 1 shown in FIG. 1, the reproduced output signals are an output ea x shifted by +α, an output e1 .x shifted by +b, as shown in FIG. 2(b). The output ej'f1 shifted by -α and the output ej'f1 shifted by h is reproduced as shown by the solid line 5.

Note that the broken line 6 in FIG. 2 (, 6) is based on logical calculation.

This is the playback output signal.　　　　.

#! In Fig. 2(b), the reproduction output signal line No. 6 is shown as 1ls5.
The measurement is performed by a measurement circuit 60 shown in the figure. In the figure.

5 51 is a device under test, and the master data 1 is read out by the magnetic head 4 of this device under test 51 and sent to the amplifier 8.
The playback signal is amplified by .

It is input to the measuring device 60. This measuring device 50 is.

An amplifier 9 that amplifies the input signal and this signal.

6. A/I) converter 10 that converts the signal into A/D, and a microphone.

Locomputer 1 and this microcomputer.

A memory 2 for storing the calculation results of 11, etc., and a calculation.

It is comprised of a display 14 and a printer 15 for displaying and printing results and the like. 5 The microcomputer-1 outputs an output ea which is a reproduced output signal.
, ea' and ej, e4' to calculate the amount of deviation from the center. In terms of the characteristic graph in Figure 2, this operation is at the center if + ea ``eg''* ej = e4', and e, >ea' s ej >
If ej', it is basically shifted in the + direction from the center. An example of this processing program is shown in FIG. In the figure, 41 indicates a step of processing until the master tape of FIG. 1 is loaded with the magnetic head 4 and the obtained reproduction output is stored in the memory, and 42 is a step of determining whether there is an amount of deviation. Step 43 is a step for determining the direction of deviation. 44 pig breeding method, standard amount set by formula [-(-α10b
)) step to determine whether the deviation is greater than or equal to 45
This step has the same meaning as step 44,
The reference amount is l(α-b). 46 is the reference amount 2 (a
10A).

(a) Calculation formula for calculating the characteristic curve (resolution α) Calculation formula for calculating the deviation amount Δl (ml: = 1eb-'eh'toa (pm)).

This step is performed by 48 is a case in which the reference amount - (a-5 6) is exceeded, and (a) the characteristic curve (resolution α) is calculated using the formula [・=-Nonimi (μm/V)].
, -ej Nau to Naka) Calculation of deviation amount Δl is performed using the formula
4=ebt l·α (μ=/y>).

410 is a calculation result output process. Furthermore, step 47
and 49 are cases where only the direction of deviation is different and the amount of deviation is within the reference amount.

The calculation basis for the characteristic curve and deviation amount calculation formula is the fourth
In the case of steps 47 and 49 in the figure, it can be found in the fifth step, but this is (-bus1--aeg2-e42 e
a2-ej2 and (lea2-6g2'l '' 1eA2 ej2'
It can be applied when l) is guaranteed, and in reality, the measurement error is (1ea2-ea2'l l) 1eb
2-eb2'l). Gatte measurement.

In order to reduce the influence of constant errors, the characteristic curve and.

The deviation amount Δ is calculated by averaging the playback output differences using the following formula.

become.

In the case of steps 46 and 48 in Fig. 4, if ■ is translated in parallel along the horizontal axis by ∆l as shown in Fig. 6, ∆l
The absolute amount of is (1ej2-ej2'l ×ta,)
Find ea2-eJ2.

I can do it. This also applies in actual cases. This is evident in Figure 6 (Ie-2-e-2'
l 'J cannot be used because it becomes constant when the amount of movement exceeds α h -a ゛ and [□] cannot be used because it differs from the actual value ea2-8
42 Yes. However, it is not possible to exceed b or -4.

No, but in this case a constant value (b or -b)5 becomes.

Each step shown in FIG. 4 is executed by the microcomputer 11.
ignites and outputs the calculation result to the display device 14 or printing device 13, the tracking deviation amount Δ of the a and a air heads is calculated.
l can be obtained automatically in a short time.

Note that 1 resolution α is the amount of displacement (μm) per unit reproduction output (voltage). The present invention can also be applied to fixed/RAD magnetic disk drives.

Effect of the invention As described above, according to the present invention, the recording medium can be prepared.

Record the data that deviates from the reference position by a predetermined amount.

This is done by calculating the output signal obtained by reproducing this master data.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the data of the magnetic head tracking according to the present invention and the relative position of the magnetic head, and FIG.
2 is a graph diagram showing the value of a reproduced output signal. FIG. FIG. 5 is a block circuit diagram including a device under test according to the present invention;
FIG. 4 is a diagram showing the calculation steps of the microcomputer shown in FIG. 6, and FIGS. 5 and 6 are diagrams for explaining the principle of the calculation steps shown in FIG. 4. be. Explanation of symbols 1.0. Master tape (recording medium), 2... Recording date, 3... Device to be measured, 50... Measuring device, 9.
. . . Amplifier, 10 . . . Le converter, 11 . . . Microcomputer, 12 . . . Memory, 42 . 46... Misalignment direction determination step, 45 and 44...
Step of determining whether the measured value deviates from the reference value. 0 46 to 49: deviation amount calculation step. 5 Representative Patent Attorney Usui 1) Oro 7. Yuki, ゛・ :120 ・ 8 ・ 1st m 2nd mouth (of) (,A'7′”) 3rd [!If 4th-mouth

Claims (1)

[Claims] A magnetic head tracking measurement blade that measures the amount of positional deviation between a fixed magnetic head and a recording medium. The first method includes a recording medium on which a plurality of pieces of recorded information are recorded in advance at a position shifted from a center position by a predetermined distance, and the magnetic head reads out a plurality of pieces of recorded information on the recording medium.
and a second step of comparing the output values of the plurality of recorded information.
With the process. A magnetic head tracking measurement method comprising: a third step of calculating a direction of deviation and an amount of deviation according to the comparison result obtained in the second step.