JPH07105018B2 - Head positioning method in magnetic tape device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for positioning a signal conversion head in a magnetic tape device.

[0002]

2. Description of the Related Art In recent years, there has been a demand for increasing the capacity of a magnetic tape device, that is, a streamer, as an external storage device of a computer. In order to respond to this, a large number of tracks are formed in the width direction of the magnetic tape, and the width of one track is extremely narrow, for example, 0.15 mm. Therefore, the positioning error of the magnetic head with respect to the desired track is extremely small. Therefore, even if the magnetic head is mechanically moved by a predetermined amount by the stepping motor or the like toward the desired track of the magnetic tape that is mechanically positioned to position 1, the desired track cannot be reproduced with a slight error. May become. In order to solve this kind of problem, Japanese Patent Laid-Open No. 63-149817 or US Pat.
No. 984 discloses that first and second test signals are recorded on a tape and the position of the head is determined based on the first and second test signals.

As a method similar to the method disclosed in the above-mentioned publication, for example, in the area before the data recording area of the first track, which is selected from a plurality of tracks and is called, for example, track zero, for example, in the above-mentioned publication. It is conceivable to record a reference burst composed of, for example, a square wave of 250 kHz in the same manner as the test signal of No. 1 and use this as a reference signal for adjusting the gain of the reproduction amplifier and a reference signal for head positioning. .

[0004]

By the way, the reference burst track has a relatively short track length in order to enable the effective use of the tape and the rapid start of the recording or reproducing of the data. Therefore, it is difficult to accurately determine the tape width direction position (height position) of the head during one run of the reference burst track.
While the head is moved in the tape width direction (vertical direction) and the reference burst is detected (retrieved), the reference burst track portion is made to travel multiple times in both the forward and reverse directions. I needed it. Therefore, the same area of the tape is repeatedly scanned, and the tape is damaged at this portion, which shortens the life of the tape. Further, since there is a time loss due to the tape traveling direction switching, the time required for positioning the head becomes long.

Therefore, it is an object of the present invention to provide a method capable of preventing damage to a tape and positioning the head quickly.

[0006]

In order to achieve the above object, the present invention is directed to a recording medium magnetic tape having a reference track on which a reference signal is recorded in addition to an information track on which an information signal is recorded. Magnetic head for reproducing the information signal by dynamic scanning motion and a magnetic tape for running the magnetic tape so that relative scanning motion is generated between the magnetic tape and the reproducing head. In a magnetic tape device including a tape traveling device and a head moving device for sending the reproducing head in a direction crossing the reference signal track, the magnetic tape is made to travel and the reproducing head is Recognizing the reference signal track by moving from a predetermined position outside the reference signal track in a direction intersecting the reference signal track and detecting the amplitude level of the output signal of the reproducing head. Position of the reproducing head to the reference signal track, and thereafter, when the reproducing head scans the information track, the reproducing operation is performed for a period until it is detected that the reproducing head crosses the reference signal track. The present invention relates to a head positioning method, wherein a moving speed of the head is set to be higher than a moving speed of the reproducing head after the reproducing head crosses the reference signal track.

[0007]

According to the present invention, when the head is positioned with respect to the reference signal track (for example, the reference burst track of the embodiment), the moving speed of the head is increased until the reference signal track is detected, Since the size is reduced after the signal track is detected, the time required for positioning the head with respect to the reference signal track can be shortened. As a result, the reference signal track can be detected and the head can be positioned there by traveling once in the reference signal track section or with a smaller number of times of travel than in the past. Therefore, it is possible to eliminate or reduce the switching of the tape traveling direction when the head is positioned, and it is possible to prevent the tape from being damaged. Since the moving speed of the head becomes low after the reference track is detected, it is possible to accurately detect the position of the reference signal track.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic tape device according to an embodiment of the present invention and a head positioning method using the same will now be described with reference to FIGS. In the magnetic tape device of this embodiment, data is recorded and reproduced by using a data cartridge 1 manufactured by Sriem Company. FIG. 2 shows the configuration of the data cartridge 1. The data cartridge 1 includes a pair of reels 3 and 4, a recording medium magnetic tape 5, a drive belt 6, a belt drive wheel or capstan 7, and a pair of tape guide pins 8 and 9 in a case 2 shown by a broken line. When,
It is configured by accommodating a pair of belt pulleys 10 and 11 and a hall detecting mirror 12. The belt 6 is endlessly hung between the capstan 7 and the pulleys 10 and 11, and is in contact with the outer contact surfaces of the tape winding portions 5a and 5b of the first and second reels 3 and 4. Therefore,
When the belt 6 is driven in the direction of arrow 13, the tape 5 runs in the direction of arrow 14.

A capstan 7 is provided outside the cartridge 1.
A roller 15 for driving the tape 5 and
The composite magnetic head 16 and the BOT and EOT Hall sensor 17 which are in sliding contact with the are arranged. Note that, in FIG. 1, the arrangement positions of these are different from those in FIG. 2 for convenience of illustration.

The composite magnetic head 16 is shown as one block in FIG. 1, but in reality, as shown in FIG. 3, a forward direction recording head 18, a forward direction reproducing head 19, and a backward direction recording head. A head 20, a reverse reproduction head 21,
And an erasing head 22.

The magnetic tape 5, as shown in FIG.
It has the tracks T0 to T28 of the book. Of these, the upper half T
0, T2, T4, T6, T8, T10, T12, T14, T1
1, indicated by 6, T18, T20, T22, T24, T26, T28
Five tracks are forward running recording tracks and are arranged in the lower half, and the remaining 14 odd-numbered tracks are backward running recording tracks. The first end side of the tape 5 is provided with first, second and third BOT holes (markers) each consisting of two holes so that the starting end can be detected in three steps, and further data recording is performed. A hole 24 indicating a start position (load point) is provided.

A reference burst (reference signal) track 25 is provided between the data recording area of track zero indicated by T0 and the beginning of the tape. Here, for example,
A 250 kHz square wave is recorded at a given amplitude level. The width of the recording tracks T0 to T27 and the width of the reference burst track 25 are almost the same as the track width (gap width) of the recording heads 18 and 20, for example, 0.1.
It is 5 mm. On the other hand, the track width (gap width) of the reproducing heads 19 and 21 is about 0.10 mm, which is smaller than this. The reference burst track 25 has a length of about 54.
.About.60 inches (1.371 to 1.524 m). Although not shown on the end side of the tape, an EOT hole is provided on the end side and a reference burst is recorded in the portion before the track T1.

Referring again to FIG. 1, a recording signal processing circuit 26 and a reproduction amplifier 27 are connected to the head 16. Actually, a switching circuit for the recording heads 18 and 20 and a switching circuit for the reproducing heads 19 and 21 in the forward and reverse directions shown in FIG. 3 are interposed between them, but for ease of explanation. It is omitted. The recording signal processing circuit 26 forms a recording signal corresponding to the recording data and the reference burst supplied from the microprocessor or CPU 28 and sends it to the head 16. The regenerative amplifier 27 is capable of gain control, and has a predetermined gain in response to a gain control signal given from the CPU 28 to the control terminal. A waveform shaping circuit 29 and a reproduction data forming circuit 30 are sequentially provided at the output stage of the reproduction amplifier 27, and an output line of the reproduction data forming circuit 30 is connected to the CPU 28.
A branch line is provided at the output terminal of the regenerative amplifier 27,
A peak hold circuit 31 for reference burst detection is connected here. This peak hold circuit 31
Holds the peak of the amplitude of the reproduction output of the reference burst track 25 and sends it to the CPU 28. CP
U28 has an AD conversion function, converts the peak value into a digital signal, and stores it in the RAM 33.

CPU 28 for configuring a computer
The ROM 32 and the RAM 33 are connected to the memory means, and the interface 34 is connected to. CPU
Reference numeral 28 controls running of the tape 5, positioning control of the head 16, gain control of the reproducing amplifier 27, and the like. Details of these will be described later.

Drive roller 1 for running the tape 5
A speed controllable motor 35 is coupled to the motor 5, and the motor 35 is connected to a control and drive circuit 36. The control and drive circuit 36 drives the motor 35 so that the tape 5 runs at the speed designated by the CPU 28.

The head 16 is placed in the width direction (vertical direction) of the tape 5.
The head 16 is coupled to a stepping motor 38 via a lead screw mechanism 37 for moving to. A control and drive circuit 39 connected between the stepping motor 38 and the CPU 28 controls the stepping motor 38 to change the height of the head 16 according to an instruction from the CPU 28.

[0017]

[Operation] A forward reproduction head 19 included in the head 16 based on reproduction of the reference burst track 25.
When positioning the center of the second BOT hole 23b according to the program stored in the ROM 32, the CPU 28 positions the center of the reference burst track 25.
The tape 5 is rewound and stopped until is detected by the sensor 17, and then the motor 35 is controlled so that the tape 5 travels in the forward direction. At this time, as shown in FIG. 6A, the tape 5 is run at 45 ips, which is lower than the speed 80 ips of the tape 5 at the time of recording / reproducing of the data area 40. By lowering the running speed of the tape 5, the same effect as when the reference burst track 25 is lengthened can be obtained. Simultaneously with the running of the tape 5, the head 16 is moved toward the reference burst track 25 from the mechanically determined initial position P0 shown in FIG.

Since the cartridge 1 is loaded in a predetermined position of the magnetic tape device, the magnetic tape 5 runs at a predetermined position and the reference burst track 25 is formed at the predetermined position. However, due to the error in the height position of the tape 5 with respect to the initial head position P0 and the position error when forming the reference burst track 25 with respect to the tape 5, the planned central position Pa of the reference burst track 25 and the actual central position are And do not necessarily match. Therefore, it is necessary to actually detect the reference burst track 25. Therefore,
First, the head 16 is moved from the initial position P0 to the reference burst scheduled center position Pa. Since the distance from P0 to Pa is a value determined by design, the stepping motor 38 is given a step pulse corresponding to this distance to move the head 16 to Pa. The movement of the head 16 from P0 to Pa is t0 to t1.
Has been achieved in the period. In FIG. 5, the line 41 indicates the head 1.
The movement locus of the center of the reproducing head 19 included in 6 is shown in principle. Since the line 41 is represented with the horizontal axis representing time and the vertical axis representing distance, the movement speed can be known from the inclination of the line 41. In this embodiment, the stepping motor 38 operates at a speed of 8 to 10 ms / 1 step (about 0.0203 mm) in the section t0 to t3, and operates at a speed of 50 ms / 1 step in the section t3 to t9. That is, the reproducing head 19 is moved at a high speed until the reproducing head 19 detects the reference burst, and after the detection, the reproducing head 19 is moved at a lower speed than that before the detection for accurate detection. As a result, the time required for detecting the reference burst track 25 can be shortened.

Positioning the reproducing head 19 at the predetermined center position Pa means positioning at the track zero indicated by T0, and can be called a calibration operation or an initialization operation. As described above, even if the reproducing head 19 is positioned at the predetermined center position Pa, it does not always coincide with the actual center of the reference burst track 25. Therefore, the actual reference burst track 25 is detected next. For this purpose, first, the reproducing head 19 is moved to the position Pb outside the reference burst track 25. This position Pb is a position obtained by -10 steps from Pa, and the distance from Pa to Pb is 0.203 mm, for example.

The operation after time t2 in FIG. 5 follows the flowchart in FIG. When positioning is started at block 50 in FIG. 8, the reproducing head 19 moves toward the reference burst track 25 from the time t2 by the forward step operation according to block 51, and the stepping motor 38
The peak value of the output amplitude of the regenerative amplifier 27 is held by the peak hold circuit 31 at every predetermined step (1 step), and this is read by the CPU 28. Since the cycle of the reference burst is sufficiently shorter than the step cycle of the stepping motor 38, this peak value can be read. Reference burst detection period t2 to t9
Alternatively, at t1 to t9 or t0 to t9, the gain of the regenerative amplifier 27 is made higher than that at the time of detecting data in the data area 40. In the section from t2 to t9, the reproduction output level (peak level) is detected in each step, and the difference between the reproduction output level of the previous step and the reproduction output level of the subsequent step is calculated as shown in block 57 of FIG. . When the reproducing head 19 is raised from t2, a part of the reproducing head 19 is moved to the reference burst track 25.
A part of is scanned and a reproduction output is obtained. Although noise is mixed in this playback output, it is possible to cancel the noise component by obtaining the difference between the output of the previous step and the output of the subsequent step, and to know the change in the playback output accurately. You can The difference in the reproduction output is 0.1 at t3.
When it becomes V or more, the CPU 28 determines that the reference burst track 25 is detected according to the block 52 of FIG.

When detecting the center of the reference burst track 25, first, t3 to t4 of FIG. 5 and FIG. 8 and FIG.
As shown in block 53, the reproducing head 19 is moved down one step from the Pc position to the P1 position, and the reproduction output level at this position is read in as shown in block 54.
The data is stored in the RAM 33, and the center detecting operation of the reference burst track 25 is started from this P1 position. In this embodiment, the 5-step reproducing head 19 is raised from the P1 position, the reproducing output level is read at each step position P2, P3, P4, P5, and the reproducing output A of the previous step is read.
And the difference B-A between the reproduction output B of the subsequent step and the reproduction output B of the subsequent step is calculated.
This operation is performed as shown in blocks 55-52 of FIG.

As shown in FIG. 6B, the reproducing head 19 is moved stepwise from P1 to P6, and if it is assumed that the center of the reference burst track 25 is located between P3 and P4, the reproduction is performed. The output level changes as shown in FIG. Since the actual positional relationship between the reference burst track 25 and the reproducing head 19 changes variously, the reproducing output level corresponding to P1 to P6 also changes variously. However, a certain regularity is recognized in the positional relationship between the reproduction output levels of P1 to P6 and the reference burst track 25. Therefore, in this embodiment, paying attention to this regularity, P1 to P6 are based on the reproduction output levels of P1 to P6.
And the reference burst track 25 are judged, and the reproducing head 1 is adjusted so that the center of the reproducing head 19 coincides with the actual center of the reference burst track 25.
Correct the position of 9.

In order to judge the positional relationship between the reproduction output levels of P1 to P6 and the reference burst track 25,
Information shown in FIGS. 7A to 7G is written in the ROM 32 of FIG. The graph of FIG. 7 shows in analog form the reference signal (data) for head position determination written in the reference table of the ROM 32, where the horizontal axis is 1,
2, 3, 4, and 5 are t5, t6, t7, and t in FIGS.
It corresponds to time points 8 and 9. The vertical axis represents t in FIGS. 5 and 6.
The integrated value of the difference B-A between each reproduction output level B from 5 to t9 and the reproduction output level A at the immediately preceding step is shown as a relative value. The upper line L1 and the lower line L2 in each graph indicate the upper and lower limits of the reference value. In the reference table of the ROM 32, not all the data of the lines L1 and L2 of FIG. 7 are written, but only the data of the intersections shown by the black circles are written. The number of steps described on the right side of each graph indicates the position correction data of the reproducing head 19 written in the reference table of the ROM 32 together with the head position determination reference signal (graph information). The information shown in FIG. 7 can be statistically obtained by forming the reference burst track 25 a plurality of times by using a plurality of tape cartridges in each of a plurality of mass-produced magnetic tape devices and executing this detection a plurality of times. it can. Of course, this information is determined in consideration of the size error of the gap in the head 16 and the like.

Actual reference burst track 25
When the center of is detected, as shown in FIG.
T5 based on the reproduction outputs V1 to V6 obtained on the basis of 9
From t9 to t9, the following arithmetic processing is executed by the CPU 28. At t5 V2 -V1 = D1 t6 At V3 -V2 = D2 and D1 + D2 = Da t7 At V4 -V3 = D3 and D1 + D2 + D3 = Db t8 At V5 -V4 = D4 and D1 + D2 + D3 + D3
At Dct9, V6 -V5 = D5 and D1 + D2 + D3 + D4 +
D5 = Dd In FIG. 8, when the operation of the six steps t4 to t9 is completed in block 58, the operation according to blocks 59 and 60 is started. As described above, since t5 to t9 correspond to 1 to 5 on the horizontal axis of FIG. 7, D1 and Da to Dd obtained by the calculation of the steps of t5 to t6 are L1 of the graph of FIG. 7A. It is determined whether or not it falls within the range from to L2. If Figure 7
In the case of entering between L1 and L2 in (A), the actual head position determination detection signals (D1, Da to Dd) are as shown in FIG.
The head position determination reference signal (data between L1 to L5) of No. 1 is used, and the CPU 28 gives a -2 step position correction signal to the stepping motor 38.
As a result, the stepping motor 38 causes the reproducing head 19 to move.
Lower the position from P6 to P4 in FIG.
Positioning is completed as shown in block 61. As a result, the center of the reproducing head 19 substantially coincides with the center of the actual reference burst track 25.

If the calculated head position determination detection signals (D1, Da to Dd) do not fall between L1 and L2 in FIG. 7A, the second signal in FIG. It is checked whether or not it falls between L1 and L2 of the pattern. When it is found that the time is within this period, the reproducing head 19 is corrected by -3 steps.

Further, in the case where it does not fall into any of L1 to L2 in FIGS. 7 (A) and 7 (B), it is further examined whether or not it falls into any of FIGS. 7 (C) to (G). Correct the head position.

Head position determination detection signals (D1, Da to Dd) shown in FIGS. 7A to 7G have seven patterns of L1 to.
When it does not fall into any of L2, the range of movement of the head 16 in the width direction of the tape 5, that is, the positional relationship between the head 16 and the reference burst track 25 in the width direction is slightly changed (see, for example, FIG. 6). Retry by slightly increasing the positions of P0 to P6 in the above. If the pattern does not fall within the seven patterns even after retrying a plurality of times, it is determined that the reference burst cannot be detected, and the reproducing head 19 is returned to Pa in FIG.

When no retry is performed, the read head 19 is positioned by the reference burst track 25.
The recording is ended while the tape section in which is formed is reproduced and scanned once. After the positioning of the reproducing head 19 is completed, the reproduction of the data area 40 is started. When reproducing the data area 40, the tape speed is increased to 80 ips as described above. Truck T0
When the reproducing head 19 is moved to any other track, the reproducing head 19 is moved with reference to the corrected position of the reproducing head 19 with respect to the reference burst track 25. Since the CPU 28 has a built-in counter for managing the step operation of the stepping motor 38, the positioning of the reproducing head 19 can be easily achieved by utilizing this counter.

[0029]

MODIFICATION The present invention is not limited to the above-mentioned embodiments, and the following modifications are possible. (1) When the same operation is repeated a plurality of times because it cannot be detected in one operation that the head position determination detection signal is input between L1 and L2 shown in FIGS. 7 (A) to (G). At the time of (retry), a pattern different from the pattern shown in FIG. 7 can be written and placed in the ROM 32 in advance and used. (2) In the embodiment, the center position of the reference burst track 25 is determined based on the difference between the reproduction outputs of two adjacent steps. Instead, the reference burst is determined based on the reproduction output itself shown in FIG. 6C. The center of the track 25 may be determined. That is, the head position determination reference signals corresponding to V1 to V6 in FIG. 6C can be stored in the reference table of the ROM 32. (3) Instead of the stepping motor 38, another DC motor can be used. (4) Although the AD conversion of the output (reproduction output) of the peak hold circuit 31 is executed by the CPU 28 in the embodiment, the AD converter can be individually connected to the output stage of the peak hold circuit 31. (5) It is also applicable to a magnetic tape device using a flips type tape cassette.

[Brief description of drawings]

FIG. 1 is a block diagram showing a magnetic tape device according to an embodiment of the present invention.

FIG. 2 is a plan view showing the cartridge of FIG. 1 in detail.

FIG. 3 is a front view showing the magnetic head of FIG. 1 in detail.

4 is a diagram showing in detail a part of the magnetic tape of FIG.

FIG. 5 is a diagram illustratively showing a locus of movement of a head when a reference burst track is detected.

FIG. 6 is a diagram showing a tape velocity when the head is positioned using a reference burst track, a moving path of the head,
FIG. 6 is a diagram showing a reproduction output voltage.

7 is a diagram showing a reference signal for head position determination and correction data stored in a reference table of the ROM of FIG.

FIG. 8 is a diagram showing a flow of a head positioning operation.

[Explanation of symbols]

 5 tape 16 head 28 CPU 31 peak hold circuit 32 ROM 38 stepping motor

Claims (1)

[Claims] 1. A reproducing head for reproducing the information signal by relative scanning movement with a recording medium magnetic tape having a reference track on which a reference signal is recorded in addition to an information track on which the information signal is recorded. , A magnetic tape running device for running the magnetic tape so that a relative scanning motion is generated between the magnetic tape and the reproducing head, and in a direction crossing the reference signal track. A magnetic tape device comprising a head moving device for feeding the reproducing head, wherein the reproducing tape is made to travel and the reproducing head crosses the reference signal track from a predetermined position outside the reference signal track. Direction to detect the amplitude level of the output signal of the reproducing head to recognize the reference signal track and position the reproducing head on the reference signal track. Then, when the reproducing head scans the information track, the reproducing head moves the moving speed of the reproducing head until it is detected that the reproducing head crosses the reference signal track. A head positioning method characterized in that the moving speed of the reproducing head after crossing the signal track is made higher.