JP2001297416A - Method and device for inspecting magnetic recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for inspecting a magnetic recorder capable of recognizing a recording width of recording track for a short time, and recognizing relative height of head magnetically. SOLUTION: Tracks Ach and Bch are recorded on a magnetic tape with a recording head WA by using the timing tracking technique adopted in a DDS. The calibration operation of the recording head WA is performed to determine a tracking timer value Ta, then the recording widths of recording tracks Twa and Twb and the relative height of the head are determined by calculation from the determined tracking timer value Ta.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method and an inspection apparatus for a magnetic recording apparatus having a rotating head, and more particularly to an inspection method and an inspection apparatus for a magnetic recording apparatus for inspecting a recording track width and a relative head height. .

[0002]

2. Description of the Related Art Conventionally, a rotary head 2 as shown in FIG.
In the magnetic recording apparatus having the recording head 1, the recording track width is checked by using the magnetic tape 22 recorded by the rotating head 21.
Was developed and recognized using a microscope.
The inspection of the relative head height is performed by visually recognizing the lower end relative height using a high-magnification optical system lens with the magnetic tape 22 loaded on the rotary head 21 as shown in the drawing, or by using an image recognition method. By optical recognition.

[0003]

Although the recording track width greatly affects the reliability of the magnetic recording apparatus, the above-mentioned conventional method requires a great amount of inspection time, and guarantees the reliability by 100% inspection. Was not possible due to time constraints.

In the above-mentioned conventional method, the relative height of the head, which determines the track width, is also reduced by the magnetic head lower end M corresponding to the lower end of the magnetic flux MF as shown in FIG.
No matter how much the optical recognition accuracy is improved, the relative head height accuracy is not improved due to the influence of the displacement between the head E and the lower end PE of the optical head. The reason for this is that the reliability cannot be improved.

An object of the present invention is to provide a method and apparatus for inspecting a magnetic recording apparatus capable of recognizing a recording track width in a short time and magnetically recognizing a head relative height. Is what you do.

[0006]

In order to solve the above-mentioned problems, a tracking timer value is obtained from a recording signal by a calibration operation using a timing tracking technique employed in a DDS, and a recording track is calculated by calculating the tracking timer value. The width and the relative height of the head are determined, and the inspection can be performed accurately in a short time.

[0007]

According to the first aspect of the present invention, when inspecting a magnetic recording apparatus having a rotary head on which a recording head and a reproducing head are mounted, a timing tracking technique employed in DDS is used. Then, a tracking timer value is obtained from the recording signal by a calibration operation, and the recording track width is calculated using the obtained tracking timer value.

[0008] With this configuration, the recording track width can be recognized in a short time, and therefore, it is possible to perform the track width inspection of all the tracks, thereby improving the reliability of the magnetic recording apparatus. Here, DDS stands for Digital Data Storag
e is an abbreviation for e, which means a magnetic recording / reproducing apparatus that records digital data on a 4 mm magnetic recording tape.

According to a second aspect of the present invention, in the configuration of the first aspect, a track is recorded on the magnetic recording tape by the recording head as a head moving time from a rotation detection signal of the rotary head to a reference signal on the track. The defined track timer value is set to the specified Ts and recorded.
The recording tracks recorded by the recording heads are reproduced a plurality of times using the first recording head while shifting the position in the track width direction, and the head output and the track timer value at each reproduction are measured. A center value of the head output is calculated from the measured value, a track timer value Ta corresponding to the calculated center value is obtained, and the recording track of the first recording head is calculated using the obtained track timer value Ta according to the following equation. Calculate the width Twa and the recording track width Twb of the second recording head. Twa = Hw−2 (Ts−Ta) · 60 / F · V0 · Tan θ Twb = Tw−Twa where Hw is the head width and F is the track. Timer clock frequency, V0 is relative speed of head to tape, θ
Is a track angle between the tape running direction and the head running direction, and Tw is a track width.

With this configuration, the recording track width can be recognized in a short time by calculation only by recording and reproducing by the magnetic recording device to be inspected. According to a third aspect of the present invention, in the configuration of the second aspect, the relative height Hab of the lower end of the recording head is calculated from the following equation using the calculated value of the recording track width: Hab = (Twa− Twb) / 2.

With this configuration, the relative height Hab of the lower end of the recording head can be magnetically recognized by calculation only by recording and reproducing by the magnetic recording device to be inspected. Therefore, even in narrow tracks to achieve high capacity,
It is possible to improve the reliability of the magnetic recording device.

According to a fourth aspect of the present invention, in the configuration according to the first aspect, a track is recorded on the magnetic recording tape by the recording head as a head moving time from a rotation detection signal of the rotary head to a reference signal on the track. The defined track timer value is set to the specified Ts and recorded.
The recording tracks recorded by the recording heads are reproduced a plurality of times using the first recording head while shifting the position in the track width direction, and the head output and the track timer value at each reproduction are measured. A center value of the head output is calculated from the measured value, and a track timer value Ta corresponding to the calculated center value is obtained. Then, a track is append-recorded on the magnetic recording tape by the reproducing head using the track timer value Ta. The recording tracks recorded by the reproduction heads are reproduced a plurality of times using the first reproduction head while shifting the position in the track width direction, and the head output and the track timer value at each reproduction are measured. The center value of the head output was calculated from the measured value, and the track timer value Tr corresponding to the calculated center value was calculated. Using rack timer value Ta, the Tr, the following equation, the first recording track width Twb recording track width Twa recording head and the second recording head
And the recording track width Twa 'of the first reproducing head and the recording track width Twb' of the second reproducing head are calculated as follows: Twa = Hw-2 (Ts-Ta) ・ 60 / F ・ V0 ・ Tanθ Twb = Tw−Twa Twa ′ = Hw−2 (Ta−Tr) · 60 / F · V0 · Tan
Twb '= Tw-Twa' where Hw is the head width, F is the track timer clock frequency, V0 is the relative speed of the head with respect to the tape, θ
Is the track angle between the tape running direction and the head running direction, and Tw is the calculated value of the track width, and the following formula is used to calculate the relative height Hab of the lower end of the recording head and the relative height Hab of the lower end of the reproducing head. Hab = (Twa−Twb) / 2 Hab ′ = (Twa′−Twb ′) / 2

According to this configuration, the relative heights of the recording head and the reproducing head can be recognized in a short time by calculation only by recording and reproducing by the magnetic recording device. Therefore, the recording track width accuracy can be improved, and high reliability can be realized even with a high-capacity magnetic recording device.

According to a fifth aspect of the present invention, there is provided an inspection apparatus for performing the inspection method for a magnetic recording apparatus according to any one of the first to fourth aspects, wherein each of the recording head and the reproducing head performs recording and reproduction. Control means for controlling the head output and a track timer value defined as a head movement time from a rotation detection signal of the rotary head to a reference signal on a recording track during reproduction; A calculating means for storing the operating characteristic value and a predetermined arithmetic expression and performing an operation based on the operating characteristic value and an output value from the measuring means;

With this configuration, the recording track width, the relative height of the recording head, and the relative height of the reproducing head can all be recognized without removing the rotary head unit. (Embodiment 1) The inspection method of a magnetic recording apparatus according to Embodiment 1 of the present invention utilizes a DDS timing tracking technique, and the principle thereof will be described below.

First, DDS timing tracking will be described. When reproducing a recording track of a magnetic tape recorded by a magnetic recording device having a rotating head, when the reproducing head 1 passes through the center of the recording track 2 at a head speed V, as shown in FIG. The time required from a rotation detection signal (hereinafter referred to as a reference PG signal) 3 to a reference signal (hereinafter referred to as a subcode) 4 on the recording track 2 is represented by T. When the reproducing head 1 is deviated from the track center by Δd, the time required from the reference PG signal 3 to the subcode 4 is T1 and is deviated from T by Δt. Therefore, if the tape running speed is controlled so that the time from the reference PG signal 3 to the subcode becomes T, the reproducing head 1 always passes through the recording track center.

The operation for determining T, that is, the calibration operation, will be described. As shown in FIG. 2, the reproducing head 1 scans the recording track 2 in the track width direction, and measures the head output at each of the scanned positions n to n + 4 and the time from the reference PG signal 3 to the subcode 4. . Then, the center value of the head output is calculated from the measurement data by the least square method, and the time T2 corresponding to the calculated center value C is set as the tracking target time T of the reproducing head 1. (Embodiment 1) An inspection method and an inspection apparatus for a magnetic recording apparatus according to the present invention using the timing tracking technique will be described.

As shown in FIG. 3, the inspection apparatus of the present invention
Inspection of a magnetic recording apparatus that has a conventional type of rotary head 11 in which recording heads WA and WB and reproducing heads RA and RB are attached to a cylinder so as to be 180 ° opposite to each other, and performs recording and reproduction on a magnetic tape 12. As will be described later, a control unit 13 for controlling recording and reproduction of the rotary head 11 and a measurement for measuring a head output during reproduction and a time from the reference PG signal 3 to the subcode 4 as described later. A means 14 and a calculating means 15 for storing an operation characteristic value of the rotary head 11 and a predetermined calculation formula in advance and performing a calculation based on an output from the measuring means 14 are provided.

In such a configuration, the control means 13 controls the recording heads WA and WB of the rotary head 11, and as shown in FIG.
The track is recorded in (s), and each recording head WA, WB
To obtain the recording tracks Ach and Bch.

Next, a calibration operation is performed on the recording track Ach recorded by the recording head WA using the same recording head WA, and the head output and the reference PG signal 3 to the subcode 4 at that time are output. The time is measured by the measuring means 14, and the timer value Ta (s) is obtained by the calculating means 15 based on the output from the measuring means 14.

Further, the calculating means 15 uses the track timer value Ta (s) obtained and calculates the recording track width Twa (μm) of the recording track Ach and the recording track width Twb (μm) of the recording track Bch from the following equation. ) Is calculated.

Twa = Hw−2 (Ts−Ta) · 60 / F · V0 · Tanθ Twb = Tw−Twa where Hw is the head width (μm), F is the track timer clock frequency (Hz), and V0 is the tape. The relative speed (μm / s) of the head, θ is the track angle (°) between the tape running direction and the head running direction, and Tw is the track width (μm).

The above equation is derived from the fact that the distance indicated by Δt ′ in the figure is (Ts−Ta) · V0 and the distance indicated by Δd ′ is (Ts−Ta) · V0 · Tanθ. Things.

Next, the calculated recording track width Twa (μ
m) and the recording track width Twb (μm), the relative height Hab (μm) of the lower end of the recording head, that is, the lower end of the gap of the recording head WB with reference to the lower end of the gap of the recording head WA, is calculated from the following equation. Is calculated.

Hab = (Twa−Twb) / 2 In this manner, recording by the magnetic recording apparatus to be inspected is performed.
The recording track widths Twa and Twb and the magnetic relative height Hab of the lower end of the recording head can be calculated in a short time just by reproducing.
Can be recognized.

Accordingly, the reliability of the magnetic recording apparatus can be improved by performing a total track width inspection and controlling the tape running speed so as to eliminate deviations of the calculated recording track width Twa and recording track width Twb from the respective prescribed values. The improvement of the performance can be realized.

The magnetic relative height H at the lower end of the recording head
Since ab can be recognized with high accuracy, the adjustment accuracy can be improved about twice as compared with the conventional method based on optical recognition.
Therefore, the recording track width accuracy can be improved, and high reliability can be realized even for a high-capacity magnetic recording device.

Here, A used in DDS
The azimuth recording method of ch and Bch has been described as an example. (Embodiment 2) FIG. 5 shows Embodiment 2 of the present invention.
This will be described with reference to FIG. The second embodiment corresponds to claim 4.

In FIG. 5, similarly to the first embodiment, the recording tracks Ach are recorded by the recording heads WA and WB.
1, Bch1, Ach2, and Bch2 are recorded. For example, a timer value Ta (s) is obtained for the recording track Ach2, and the recording track width Twa (μm) of the recording track Ach2 and the recording track width Twb (μm) of the recording track Bch2 are recorded. The relative height Hab (μm) of the lower end of the head is calculated.

At the same time, recording tracks Ach1 and Bch
The reproducing heads RA and RB are controlled by the control means 13 after 1, Ach2 and Bch2, and the timer value T obtained earlier is obtained.
a (s), append recording is performed, and each reproduction head RA,
Recording tracks Ach3, Bch3, Ach4 corresponding to RB
Bch4 is obtained.

Then, a calibration operation is performed on the recording track Ach3 recorded by the recording head WA using the same recording head WA, and the head output and the time from the reference PG signal 3 to the subcode 4 at that time are performed. Is measured by the measuring means 14, and the timer value Tr (s) is obtained by the calculating means 15 based on the output from the measuring means 14.

Further, the calculating means 15 uses the track timer value Tr (s) to calculate the recording track width Twa '(μm) of the recording track Ach3 and the recording track width Twb' (μm) of the recording track Bch3 according to the following equations. ) And the relative height Hab ′ (μm) of the lower end of the reproducing head are calculated.

Twa '= Hw-2 (Tr-Ta) .60 / F
/ V0 · Tan θ Twb ′ = Tw−Twa ′ Hab ′ = (Twa′−Twb ′) / 2 In this manner, recording is performed by the magnetic recording apparatus to be inspected.
Only by reproducing, the recording track widths Twa, Twb, Twa ', Twb', the recording head relative height Hab, and the reproducing head relative height Hab 'can be recognized in a short time by calculation.

Therefore, by adjusting the relative height of the head based on the lower end value of the head, the accuracy of the recording track width can be improved, and high reliability can be realized even with a high-capacity magnetic recording apparatus.

In the first embodiment, the recording head W
An inspection method for recognizing the recording track widths Twa and Twb for A and WB and the magnetic relative height Hab of the lower end of the head will be described. In the second embodiment, the recording track width for the recording heads WA and WB and the reproducing heads RA and RB will be described. Twa, Twb, T
wa ', Twb' and the magnetic relative height Hab at the lower end of the head
The inspection method for recognizing Hab 'has been described.
Only desired items can be selected for inspection.

[0036]

As described above, according to the method and apparatus for inspecting a magnetic recording apparatus of the present invention, recording on a magnetic tape,
Reproduction is performed, the tracking timer value is obtained from the recording signal at that time, and the arithmetic operation is performed using the obtained tracking timer value, whereby the recording track width and the relative height of the magnetic head can be recognized. The height makes it possible to improve the recording track width accuracy, so that a high-capacity, high-reliability, low-cost magnetic recording apparatus can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining DDS timing tracking which is a principle of a method for inspecting a magnetic recording apparatus according to the present invention.

FIG. 2 is an explanatory diagram illustrating a calibration operation in DDS timing tracking shown in FIG.

FIG. 3 is an explanatory diagram showing a schematic configuration of a magnetic recording apparatus inspection apparatus according to an embodiment of the present invention, together with a rotary head to be inspected;

FIG. 4 is an explanatory diagram illustrating a method for inspecting a magnetic recording device according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating an inspection method according to another embodiment of the present invention.

FIG. 6 is an explanatory view showing a rotary head of a conventional magnetic recording apparatus.

FIG. 7 is an explanatory view showing a recording head of the rotary head of FIG. 6;

FIG. 8 is an explanatory diagram showing a displacement between a lower end of a magnetic head and a lower end of an optical head in the recording head of the rotary head of FIG. 6;

[Explanation of symbols]

 3 Reference PG signal 4 Subcode 11 Rotating head WA, WB Recording head RA, RB playback head 12 Magnetic tape 13 Control means 14 Measurement means 15 Calculation means Ach, Bch Recording track Ts Initial timer value Ta Timer value Tr Timer value Twa, Twb Recording track width

Claims (5)

[Claims] When inspecting a magnetic recording apparatus having a rotary head on which a recording head and a reproducing head are mounted, a tracking timer is performed by a calibration operation from a recording signal using a timing tracking technique adopted in a DDS. A method for inspecting a magnetic recording apparatus, comprising: determining a value, and calculating a recording track width using the determined tracking timer value. 2. A track is recorded on a magnetic recording tape by a recording head by setting a track timer value defined as a head moving time from a rotation detection signal of a rotary head to a reference signal on the track to a specified Ts, and The recording track recorded by the first recording head is reproduced a plurality of times using the first recording head while shifting the position in the track width direction, and the head output and the track timer value at each reproduction are measured. The center value of the head output is calculated from each measured value, and the track timer value Ta corresponding to the calculated center value is calculated.
Using the obtained track timer value Ta, the recording track width Twa of the first recording head and the second
Twa = Hw−2 (Ts−Ta) · 60 / F · V0 · Tan θ Twb = Tw−Twa where Hw is the head width, F is the track timer clock frequency, and V0. Is the relative speed of the head to the tape, θ
2. A track angle between a tape running direction and a head running direction, and Tw is a track width.
The inspection method of the magnetic recording device according to the above. 3. The method according to claim 2, wherein the relative height Hab of the lower end of the recording head is calculated from the following equation using the calculated value of the recording track width: Hab = (Twa−Twb) / 2. Inspection method for magnetic recording device. 4. A recording head records a track on a magnetic recording tape by setting a track timer value defined as a head moving time from a rotation detection signal of a rotary head to a reference signal on the track to a specified Ts, The recording track recorded by the first recording head is reproduced a plurality of times using the first recording head while shifting the position in the track width direction, and the head output and the track timer value at each reproduction are measured. The center value of the head output is calculated from each measured value, and the track timer value Ta corresponding to the calculated center value is calculated.
Then, the track is append-recorded on the magnetic recording tape by the reproducing head at the track timer value Ta, and the recording track recorded by the first reproducing head is recorded in the track width direction using the first reproducing head. The head output and the track timer value at each playback are measured, and the center value of the head output is calculated from each measured value, and the track timer value Tr corresponding to the calculated center value is measured.
Using the track timer values Ta and Tr obtained, the following formula is used to calculate the recording track width Twa of the first recording head, the recording track width Twb of the second recording head, and the first reproducing head. And the recording track width Twb 'of the second reproducing head are calculated as follows: Twa = Hw−2 (Ts−Ta) · 60 / F · V0 · Tan θ Twb = Tw−Twa Twa ′ = Hw -2 (Ta-Tr) ・ 60 / F ・ V0 ・ Tan
Twb '= Tw-Twa' where Hw is the head width, F is the track timer clock frequency, V0 is the relative speed of the head with respect to the tape, θ
Is the track angle between the tape running direction and the head running direction, and Tw is the calculated value of the track width, and the following formula is used to calculate the relative height Hab of the lower end of the recording head and the relative height Hab of the lower end of the reproducing head. The inspection method for a magnetic recording apparatus according to claim 1, wherein: Hab = (Twa-Twb) / 2 Hab '= (Twa'-Twb') / 2. 5. An inspection apparatus for performing an inspection method for a magnetic recording apparatus according to claim 1, wherein said control means controls recording and reproduction of each of a recording head and a reproduction head. A measuring means for measuring a head output and a track timer value defined as a head moving time from a rotation detection signal of the rotary head to a reference signal on a recording track, an operation characteristic value of the rotary head and a predetermined arithmetic expression And a calculating means for performing a calculation based on the operating characteristic value and an output value from the measuring means in advance.