JP4039143B2 - Servo pattern recording method and servo pattern detection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a servo pattern recording method and a servo pattern detection method, for example, an external auxiliary storage device for data in a computer system, and more particularly to a servo pattern recording method and a servo pattern detection method in a magnetic tape recording device.
[0002]
[Prior art]
In this type of magnetic tape recording apparatus, a servo pattern is magnetically recorded in advance on a tape-shaped recording medium from the viewpoint of increasing the recording density of information recorded on a tape-shaped recording medium such as a magnetic tape and ensuring accurate reproduction. In addition, servo control of the recording (reproducing) head is performed by reproducing the servo pattern.
Conventionally, as a servo pattern recording method, a large number of servo linear recording tracks are provided on the tape-shaped recording medium along the running direction, and the servo pattern is combined with a plurality of recording heads according to the plurality of linear recording tracks. Are recorded on a linear recording track, and two wide heads are installed in a "C" shape, and a servo pattern is recorded on a large number of linear recording tracks with both heads in a "C" shape.
[0003]
[Problems to be solved by the invention]
However, as described above, in the method of recording a servo pattern by combining a large number of servo linear recording tracks and a plurality of recording heads, there is a problem that manufacturing and adjustment of the recording heads become difficult as the track density increases. In addition, there is a problem that narrowing the track pitch has certain limitations, and the servo-occupied area tends to be large, and the use efficiency of the recording surface is poor.
On the other hand, in the method in which two wide heads are arranged in a “C” shape and the servo pattern is recorded in a “C” shape on a large number of linear recording tracks, the combination head arranged in the “C” shape is used. There is a problem that the required accuracy is high and the wide-width head is expensive, and there is a problem that the resolution is not sufficient and it is vulnerable to jitter, which is also an obstacle to high track pitch density.
In addition, the magnetic recording density on the tape-shaped recording medium is determined by BPI (bits per inch) or TPI (track per inch), and in particular, linear to the most important factor that determines the TPI. The recording density performance of the recording track is pointed out.
[0004]
Normally, the servo performance of a linear recording track is determined by the accuracy of the servo pattern written on the tape-shaped recording medium. Therefore, in order to realize high-density recording, high precision and high definition of the servo pattern are required. Yes.
Furthermore, since the servo pattern is recorded and commercialized in advance over the entire length of the tape-shaped recording medium, high-speed servo pattern recording and high productivity are required from the viewpoint of cost reduction.
The present invention has been made to solve such a conventional problem, and provides a servo pattern recording method capable of recording a precise servo pattern with high accuracy and high speed by a relatively simple method and configuration. Objective.
Another object of the present invention is to provide a servo pattern detection method capable of detecting the recording position of such a fine servo pattern in a linear recording track by a simple method.
[0005]
[Means for Solving the Problems]
In order to solve such a problem, a first configuration according to a servo pattern recording method of the present invention includes a recording head having a track width wider than a recording width of a tape-shaped recording medium and recording a servo signal on the tape. An erasing head having a track width wider than the recording width of the tape-shaped recording medium is disposed on the subsequent row side with a predetermined angle with respect to the recording head, Servo signals recorded on the tape-shaped recording medium by the recording head for each recording timing period are erased by the erasing head at predetermined erasing timing intervals, and are erased in an oblique direction with respect to the width direction of the tape-shaped recording medium. The servo pattern is formed at timing intervals.
[0006]
In the first configuration, the recording head can be a fixed head or a rotary head.
In the first configuration, the recording head may partially record a special signal different from the servo signal, and include the special signal in the servo pattern.
Further, in the first configuration, the special signal can be a servo identification signal for identifying the front and rear, or a servo timing signal indicating a detection timing.
Furthermore, in the first configuration, the servo pattern can be formed by erasing it with its erasing head so that the signal for forming the servo pattern extends over a plurality of linear recording tracks.
[0007]
According to a second configuration of the servo pattern recording method of the present invention, a rotary head that rotates and moves obliquely with respect to the traveling direction of the tape-shaped recording medium is disposed in the traveling path, and the width direction of the tape-shaped recording medium By recording a servo signal on the tape-like recording medium at a predetermined recording timing period by the rotating head, the servo pattern is formed obliquely at recording timing intervals in the track direction of the rotating head.
[0008]
In the second configuration, the recording head can partially record a special signal different from the servo signal and include the special signal in the servo pattern.
Further, in the second configuration, the special signal can be a servo identification signal for identifying front and rear, or a servo timing signal indicating detection timing.
In the servo pattern detection method according to the present invention, a plurality of reproducing heads intersect with the alignment direction of servo patterns arranged obliquely with respect to the width direction of the tape-shaped recording medium and in accordance with the linear recording track. Along with the trace on the linear recording track by the reproducing head, the servo pattern is sequentially and cyclically detected by a plurality of reproducing heads corresponding to the order of appearance of the servo pattern.
[0009]
The servo pattern detection method of the present invention can be configured to obtain an output signal in which one unit is a detection signal detected from the servo pattern by one cycle.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A servo pattern recording method and a servo pattern detection method according to the present invention will be described below with reference to the drawings.
The present invention is roughly divided into first and second configurations relating to a servo pattern recording method and a servo pattern detection method.
[0011]
First, the first configuration according to the servo pattern recording method of the present invention will be described.
FIG. 1 is a diagram for explaining a first configuration which is a basic configuration according to the present invention.
The tape-shaped recording medium 1 is a conventionally known magnetic tape, for example, and previously has a plurality of linear recording tracks TCn extending in the running direction (longitudinal direction) d (see FIGS. 2 and 5; only one is shown in FIG. 2). Are defined at predetermined intervals in the width direction, and travel control is performed by known travel means, but the description and illustration are omitted because they are not the main part of the present invention.
[0012]
In the traveling path of the tape-shaped recording medium 1, a recording head 3 having a track longer than the recording width is arranged on the preceding (upstream) side so as to contact the tape-shaped recording medium 1. The recording head 3 is formed in accordance with a servo pattern reproducing head and azimuth described later.
[0013]
Erasing (recording) having tracks longer than the recording width of the tape-shaped recording medium 1 on the downstream (downstream) side of the recording head 3 in the traveling path of the tape-shaped recording medium 1 with a predetermined distance from the recording head 3. The head 5 is arranged so as to come into contact with the tape-shaped recording medium 1 with an angle θ.
The recording head 3 and the erasing head 5 are formed long enough so that the head gap covers the entire recording width of the tape-shaped recording medium 1, and the head gap of the recording head 3 is in the traveling path of the tape-shaped recording medium 1. In an orthogonal direction, the erasing head 5 is arranged so as to extend in a direction inclined by an angle (θ) with respect to the traveling path of the tape-like recording medium 1.
Both are fixedly supported by support means (not shown) in the chassis of the device.
[0014]
A recording signal output unit (not shown) is connected to the recording head 3, and servo signals are continuously recorded on the traveling tape-shaped recording medium 1 by the recording head 3. The recording servo signal An recorded on the tape-shaped recording medium 1 has the same content in the width direction of the tape-shaped recording medium 1 at each timing even if the signal content changes in time series.
The erase head 5 is connected to an erase signal output unit (not shown) for intermittently outputting a high frequency signal of, for example, several tens of kHz to several tens of MHz as an erase signal at a predetermined timing, and the tape-shaped recording medium that travels. The recording servo signal An above 1 is erased while being overwritten by the erasing head 5 based on the erasing signal output in a predetermined timing period.
[0015]
That is, as shown in FIG. 1, the recording servo signal An continuously recorded by the recording head 3 is erased based on the erasing signal output by the erasing head 5 in a predetermined timing period, and also shown in FIG. As described above, by forming an erasing timing interval without repeatedly outputting an erasing signal for an STW (servo track writer) period, erasing is performed at an erasing timing interval obliquely with respect to the width direction of the tape-shaped recording medium 1. The remaining linear servo patterns 7 are formed.
[0016]
In FIG. 2, for the sake of convenience, one servo pattern 7 is shown, but the similar servo pattern 7 is repeatedly formed before and after the traveling direction d through the erased portion of the recording servo signal An (see FIG. 20 described later).
[0017]
By adopting such a method, servo signals can be recorded or erased without using a plurality of recording heads adapted to the track width and position of each of the linear recording tracks TCn to TCn + 2,. The servo pattern 7 corresponding to the plurality of linear recording tracks TCn to TCn + 2,... Can be simply recorded and formed on the tape-like recording medium 1 only by appropriately setting the timing and the angle of each head.
Moreover, since the servo pattern 7 is formed by the fixed recording head 3 and the erasing head 5, high-speed recording can be formed, and the servo pattern 7 is dispersed spatially and in time series on the tape-like recording medium 1. Therefore, not only can the recording area be reduced, but also a good response speed can be maintained.
And this kind of tape-shaped recording medium 1 is commercialized by forming the servo pattern 7 over the entire length at a predetermined interval in the oblique direction with respect to the width direction according to the present invention.
[0018]
On the user side, for example, digital data of a computer system is recorded and reproduced between servo patterns 7 of the tape-shaped recording medium 1 by a magnetic tape recording device (not shown), and linear recording tracks TCn to TCn + 2, ... The servo pattern 7 is traced and reproduced by a reproducing head (not shown; refer to reference numeral 33 in FIG. 20) for tracing the top, servo position control of the recording / reproducing head for digital data and servo running control of the tape-like recording medium 1 Is done.
An example of a servo pattern reproduction operation by a reproducing head that traces a plurality of linear recording tracks TCn to TCn + 2,... Will be described in an embodiment of FIG.
[0019]
In the servo pattern recording method according to FIGS. 1 and 2, the entire width of the tape-like recording medium 1 is recorded and erased by a pair of the recording head 3 and the erasing head 5, but with respect to the width direction of the tape-like recording medium 1 In addition, a configuration in which a plurality of recording heads and a plurality of erasing heads are combined to perform recording / erasing is also possible.
That is, a plurality of adjacent linear recording tracks TCn to TCn + 2,... Are divided into a plurality of groups, and a plurality of recording heads 3 and erasing heads 5 are arranged for each group.
[0020]
Since the servo pattern recording method of the present invention is characterized in that the servo signals are sequentially written in time series by the recording head 3, various special signals other than the servo signals are applied to the recording servo signal An for a predetermined period. It is possible to form a servo pattern by alternately inserting and recording each time instead of the servo signal.
For example, as shown in FIG. 2, a method of periodically inserting and recording a division signal S in the middle of the servo signal An and erasing with the erasing head 5 so that the division signal S overlaps each linear recording track TCn to TCn + 2,. It is.
[0021]
As described above, when the segment signal S different from the periphery is recorded as a special signal in the middle of the servo signal An, for example, the reproduction signals of the linear recording tracks TCn to TCn + 2,. Thus, detection of the servo signal An appearing before and after the segment signal S is ensured.
For this reason, when the tape-like recording medium 1 is displaced and the track position of the linear recording track TCn changes, the output level V and the output periods T1 and T2 change regularly according to the change. It is possible to perform tracking correction by detecting the degree of change and displacing the position of the recording head or reproducing head and aligning them with the track center of the linear recording track TCn.
[0022]
Further, as shown in FIG. 4, the servo pattern recording method of the present invention provides a non-recording period between servo signals An, An + 1, An + 2, An + 3,. (ID) signal and servo timing mark signal indicating the detection timing of the servo signal are recorded by the recording head 3 so as to be alternately inserted between the servo signals An, An + 1, An + 2, An + 3,... A method of erasing at 5 is possible.
[0023]
In FIG. 4, for easy illustration, the identification signal and the servo timing are illustrated as one identification signal Bn, Bn + 1, Bn + 2,..., But can be illustrated separately. In particular, the servo signals are An to An + 3,..., And the identification signals are Bn to Bn + 2,. same as below.
Moreover, as shown in FIG. 5, erasing is performed by the erasing head 5 in the erasing timing period so that the identification signals Bn to Bn + 2 are positioned at the respective centers of the linear recording tracks TCn to TCn + 2,. Servo pattern 9 in which servo signals An to An + 3 and identification signals Bn to Bn + 2 are alternately arranged linearly is formed. The servo signals An to An + 3 may be positioned at the respective centers of the linear recording tracks TCn to TCn + 2,.
Whether or not the servo signal An is positioned at the track center of the nth linear recording track TCn with respect to such a servo pattern 9 depends on the lower edge of the servo signal An and the upper edge of the servo signal An + 1 with respect to the linear recording track TCn. It is determined by the balance of the above, and is actually determined by the unerasing timing period.
[0024]
Then, for example, when the linear recording track TCn + 1 is traced by the reproducing head on the magnetic tape recording apparatus side, a waveform as shown in FIG. 6A is obtained.
When the balanced point of the outputs of the servo signals An + 1 and An + 2 becomes the track center and the track position of the linear recording track TCn changes, the output levels of the servo signals An + 1 and An + 2 appearing before and after the identification signal Bn + 1 and the output period T1 before and after , T2 changes regularly, so that the magnetic tape recording device detects this change and the position of the recording head or the reproducing head is displaced to make tracking correction matching the track center of the linear recording track TCn + 1.
The servo signal An to An + 3,... In the servo pattern 9 and the output periods T1 and T2 before and after are detected by detecting the output peak, comparing the level for each sampling period, comparing the average output within the period, or the threshold level. A known method such as on / off binarization comparison by (THL: threshold lebel threshold) can be adopted.
In such a configuration, an example in which an ID signal or a servo timing mark signal is input as the identification signals Bn to Bn + 2,... Has been described, but these may be added to the servo signals An to An + 2,. It is also possible to assign a servo ID number as a unique address to all the identification signals Bn to Bn + 2,.
[0025]
In this case, when assigning servo ID numbers to all the identification signals Bn to Bn + 2,... Over the entire length of the tape-like recording medium 1, even if the amount of information in each identification signal Bn to Bn + 2,. All servo ID signals can be identified. Details thereof will be described later.
However, the servo pattern 9 formed in the present invention can be difficult to detect unless the reproduction head is traced to the track center of the plurality of linear recording tracks TCn to TCn + 2 and the output of the identification signals Bn to Bn + 2 is lowered. The identification signal Bn preceding the identification signal Bn + 1 may be output, causing a malfunction of signal processing, or the identification signal Bn + 1 being output later than the preceding servo signal An + 1. There is also concern that there will be no action.
[0026]
Hereinafter, the following method according to the present invention will be described with reference to FIG.
This method is similar to the configuration shown in FIG. 4 described above for recording a servo signal or the like by the recording head 3, but is characterized by an erasing method by the erasing head 5.
That is, the unerasing timing period by the erasing head 5 is lengthened so that the recording signal extends over the three linear recording tracks TCn to TCn + 2,. In FIG. 7, two lines of servo pattern tracks L1 and L2 are shown as adjacent servo patterns 9, but one line is possible as long as it extends over a plurality of linear recording tracks TCn to TCn + 2,.
In FIG. 7, the servo signals An + 3 and Cn and the identification signals Bn + 3 and Dn in adjacent servo patterns 9 in the width direction of the tape-like recording medium 1 are divided by erasing by the erasing head 5 with the same signal written at the same timing. However, it is a modification of the configuration of FIG. 5 and can be obtained simply by operating the unerased timing period.
When such a servo pattern 9 is used, for example, even when the reproducing head is not aligned with the track center of the linear recording track TCn + 1, position correction can be performed as follows.
[0027]
FIG. 8 shows the reproduction output of the track center of the linear recording track TCn + 1. For example, the reproduction signal of the reproduction head is on the -1/2 track as shown in the upper part of the figure or +1/2 as shown in the lower part. Consider the case of a downward shift.
The servo signal detection algorithm starts by searching for the servo timing mark signal of the identification signal Bn.
The signal is cut at an appropriate threshold level THL, the timing mark signal of the identification signal Bn is read, and if it can be detected, the servo ID signal of the servo signal is decoded based on it. The data instructed by the upper control CPU is recorded and the difference from the servo ID signal to be reproduced is calculated and the reproducing head is displaced by a predetermined amount in a predetermined direction, and the servo ID signal is detected. Then move on to the next servo suction operation. Detection of the servo ID signal during movement can be detected in a manner close to continuity by reducing the reading interval by a method described later.
[0028]
When a target servo ID signal is detected, a plurality of adjacent servo ID signals are detected at regular intervals. In the example shown in FIG. 8, a maximum of three servo signals and ID signals are detected.
In this detection method, when a servo ID signal as a target is detected, the servo signal that comes immediately after and the next servo signal are signals that are actually used. The comparison is performed to detect the balance.
For example, in FIG. 8, when the servo ID signal written in the identification Bn + 2 is targeted, the subsequent servo signals An + 3 and Cn + 1 are compared. When the upper stage is shifted by -1/2 track, the amplitude level of the servo signal An + 3 is 0% and Cn + 1 is 100%, and when the lower stage is shifted by +1/2 track, the servo signal An + 3 is 100% amplitude level and Cn + 1 is The amplitude level is 0%, and the servo signal can be detected based on the calculation result of the same calculation (for example, ± is the moving direction in the calculation of (An + 1) − (Cn + 1), the value is the amount to be changed and 0 is the target position)). it can.
[0029]
The target servo ID signal when the tape-like recording medium 1 travels from the reverse direction may be Dn + 1. In this case, the servo ID signal can be read from the reverse direction. However, the method can be used as the target servo ID signal as follows.
That is, there are a method of making a special code, a method of combining forward and reverse codes, a method of making an identification signal B (odd number) for assigning forward and reverse to a dedicated track the forward direction, and a backward direction of B (even number).
In addition, since the servo signals An + 1 and Cn + 1 and An + 3 and Cn + 3 exhibit the same movement, either can be used, but the use of both will increase the certainty.
[0030]
FIG. 9 shows another embodiment of the servo pattern recording method according to the present invention, and illustration of the tape-shaped recording medium 1 is omitted.
In addition to the method of forming the oblique servo pattern 9 on the tape-shaped recording medium 1 with a pair of recording head 3 and erasing head 5 as shown in FIGS. An auxiliary rotating head (not shown) that traces the tape-like recording medium 1 at an angle same as that at the rear side is arranged on the rear side, thereby tracing the tape-like recording medium 1 at a long wavelength parallel to each servo pattern 9 and at a preceding position. In this example, servo timing mark signals X, Y, and X are recorded.
Here, the preceding position means a position where the reproducing head reaches the traveling tape-shaped recording medium 1 before the servo pattern 9, and in FIG. 9, three types of servo timing mark signals X, Y, X Is an example of recording continuously.
In this way, in the configuration in which the servo timing mark signals X, Y, X formed at the preceding position of the servo pattern 9 are formed, for example, the reproducing head that traces the linear recording track TCn + 1 is always at the preceding position of the servo pattern 9 at the servo timing mark. Since the signals X, Y, and X are reproduced, a signal that comes after the timing at which the servo timing mark signals X, Y, and X are detected can be accurately recognized as a servo signal.
In addition, the servo timing mark signals X, Y, and X can be easily recorded in the same direction and continuously in the track direction of the auxiliary rotary head, and can be made a mark signal independent of the track position.
[0031]
Further, FIG. 10A eliminates the break between the servo signal and the identification signal to form the servo pattern 11 so that the servo signal can be easily searched and the low-frequency servo timing mark signals X, Y, FIG. 10B shows a reproduction signal when, for example, the linear recording track TCn + 1 is traced by the reproduction head.
[0032]
If the servo pattern 11 shown in FIG. 10A is used, the number of rises and falls during servo signal reproduction is reduced, and the detection and calculation of the output and time difference at that time are simplified, and servo timing marks are placed before and after the servo pattern 11. The signals X, Y, and X are added to make it easier to detect the servo signal and to cope with recording and reproduction from both directions.
This is intended to simplify the detection circuit by adopting a detection algorithm that uses signal breaks as timing reference signals for signal detection.
[0033]
FIG. 11 shows another servo pattern recording method according to the present invention. Servo signals An to An + 3 are recorded at intervals with the method shown in FIG. After arranging An to An + 3, the identification signals Bn to Bn + 3 are recorded in the gaps of the servo signals An to An + 3 by the method as shown in FIG. In this example, the servo signals 13 are formed by overlappingly recording the identification signals Bn to Bn + 3 a plurality of times in the gaps between the servo signals An to An + 3.
In this servo pattern 13, since the servo signals An to An + 3 are sandwiched between the identification signals Bn to Bn + 3, the servo signals An to An + 3 are read after the preceding identification signals Bn to Bn + 3 are detected, so the identification signals Bn to Bn + 3 Can be reliably detected as servo signals An to An + 3.
In any of the servo pattern recording methods described above, the recording head 3 is set in a direction orthogonal to the traveling path of the tape-shaped recording medium 1 and the erasing head 5 is set at an angle (θ) with respect to the traveling path of the tape-shaped recording medium 1. Although the example is arranged in an inclined direction, the present invention is not limited to this.
[0034]
In FIG. 12A, the recording head 15 is tilted by an angle θ with respect to the traveling direction of the tape-shaped recording medium 1, and the subsequent erasing head 17 is arranged perpendicular to the traveling direction. The erasing and unerasing timing periods are alternately repeated to form a servo pattern 19 extending in an oblique direction.
Even in the example of forming such a servo pattern 19, as in the above-described configuration, a recording head that matches the track width and position of each of the linear recording tracks TCn to TCn + 2,. The servo pattern 19 corresponding to the plurality of linear recording tracks TCn to TCn + 2,... Can be easily formed simply by appropriately setting the recording signal erasing timing and the angle of the heads 15 and 17. It has effects such as.
When such a servo pattern 19 is formed, the reproducing head for reproducing the servo signal needs to be tilted in accordance with the azimuth of the recording head 15, but the adjacent reproducing heads tracing each linear recording track TCn to TCn + 2,. The azimuth loss can be avoided because the signal can be recorded using a signal having a little longer wavelength by alternately allocating the azimuth to the plus side and the minus side.
The servo pattern recording method of the present invention is not limited to the configuration in which one of the recording heads 3 and 15 and the erasing heads 5 and 17 is disposed in a direction orthogonal to the tape-shaped recording medium 1 and the other is disposed in an oblique direction. The object of the present invention can be achieved if they are arranged so as to cross each other.
[0035]
By the way, in the servo pattern recording method of the present invention described above, when an identification signal is detected, a plurality of identification signals are reproduced depending on the pattern configuration, and a plurality of corresponding servo signals must be reproduced to identify them. There is a case.
As one of the identification methods, the method of decoding and using the identification signal has already been described, but still another identification method is possible.
[0036]
For example, when a large number of servo signals appear as shown in FIG. 7, pulse width modulation and pulse position modulation (modulation during periods P1 to Pn in FIG. 8) are applied to the servo signals. This is used as a low-cost identification method when identifying adjacent linear recording tracks TCn to TCn + 2,... Without using an identification signal including detailed identification contents as in the case of use as a streamer. It is possible.
Further, as will be described later, when a servo pattern having a plurality of identification signals having the same content in the width direction of the tape-shaped recording medium 1 appears, it is also useful to change the unerased portion of the servo pattern for each line.
That is, when width modulation is applied to the servo pattern 9 in FIG. 7 (modulation is applied to T1 and T2 in the drawing), the number of servo signals detected in the target linear recording track changes, and the identification signal becomes Even if they are the same, they can be identified by a combination with the number of servo signals generated.
For the same purpose, there is also a method of adding an identification code to servo timing mark signals X, Y, and X which are obliquely input by a subsequent recording head (not shown) in FIGS. This necessity and purpose of use will be described later.
[0037]
By the way, although the servo pattern recording method according to the present invention described above forms the servo patterns 7 to 19 using a fixed head, the present invention is not limited to this.
[0038]
Next, a method for forming a servo pattern with a helical rotary head, which is the second configuration of the servo pattern recording method according to the present invention, will be described.
As shown in FIG. 13, a recording (rotating) head having the same azimuth angle as that of a reproducing head of a magnetic tape recording apparatus (not shown) is mounted on a rotating drum (both not shown), and the running direction of the tape-shaped recording medium 1 In this case, the servo pattern 21 is formed in the rotational displacement direction.
That is, a recording signal output unit (not shown) is connected to the recording head, for example, servo signals An to An + 3,... And identification signals Bn to Bn + 3,. ..., Bn + 3,... And servo signals An to An + 3,... Sandwiching this are recorded in a switching timing period, and a servo pattern 21 extending linearly obliquely with respect to the running direction of the tape-like recording medium 1 is recorded. Record.
In such a servo pattern 21, for example, when the reproducing head is traced on the linear recording track TCn + 1, as shown in FIG. 14, the reproducing signal of the identification signal Bn + 1 and the servo signals An + 1, An + 2,. Since the periods T1 and T3 change, the magnetic tape recording device can detect this, and the recording head and the reproducing head can be accurately displaced on the linear recording track TCn + 1 to perform tracking correction.
[0039]
In the method shown in FIG. 13, since the servo signals An to An + 3,... And the identification signals Bn to Bn + 3, etc. are helically recorded, the contents of these signals and codes can be arbitrarily determined, and an ECC code (error correction code : Various error codes can be added to the identification signals Bn to Bn + 3,... Or independently, and each servo signal An to An + 3,. it can.
The servo signals An to An + 3,... Are recorded on the helical track, and the positions of the linear recording tracks TCn to TCn + 2,... Are the timing at which the servo signals An to An + 3,. Therefore, the variation in the track width of the helical recording head can be corrected in the recording timing period.
The detection of the servo signals An to An + 3,... Is based on comparison of their output levels, but can also be used for time difference detection as described above.
Furthermore, the ID numbers that can be added to the individual identification signals Bn, Bn + 3,... Do not require a large amount of information for identifying all servos. The reason will be described later.
[0040]
In FIG. 13, an example in which one servo pattern 21 is formed by one helical track has been described. However, as shown in FIG. 15, in the present invention, two servo patterns 23 on two servo tracks L3 and L4, A configuration in which 25 is formed is also possible.
That is, first, servo signals An to An + 3,... Are recorded on the servo track L3, and then servo signals Cn to Cn + 3,... Of the servo track L4 are formed between the servo signals An to An + 3,. In order to distinguish between An to An + 3, Cn to Cn + 3,..., The signal widths of both are changed.
[0041]
FIG. 16 shows an example in which servo signals An + 1 and Cn + 1 are detected in the linear recording track TCn + 1.
However, when the servo patterns 23 and 25 are formed by the method shown in FIG. 15, when the reproducing head does not pass through the track centers of the linear recording tracks TCn to TCn + 2, depending on the configuration of the servo patterns 23 and 25, for example, the identification signal Bn + 1 Since the output is reduced and cannot be detected or the servo timing mark signal is reproduced so as to be sandwiched between the servo signals, the handling may be complicated.
As a method for avoiding this, a method of widening the track width of the servo patterns 23 and 25, a method of increasing the number of tracks, or the method already described in detail with reference to FIG. 7 is useful.
Also, the servo patterns 23 and 25 created by the helical recording head are basically similar to the servo patterns 7 to 21 formed by the fixed heads 3 and 15 described above. The method for operating the servo employs the same algorithm as the above-mentioned fixed head.
[0042]
The processing described in FIG. 7 can also be applied to handling of the servo signals An + 2 and Cn omitted in FIG. However, since the servo patterns 23 and 25 by the helical recording head need not be repeated in the same form, a dedicated servo timing mark signal as shown below can be formed.
[0043]
In FIG. 17, the servo pattern 27 is recorded and formed by the helical recording head, and the servo timing signals C and D are recorded and formed parallel to each other before and after the servo pattern 27. The servo pattern 27 and the servo timing signals C and D are also preferably aligned with the reproducing head and the azimuth.
[0044]
FIG. 18 shows a signal waveform reproduced by a reproducing head obtained by tracing the linear recording track TCn + 1. Since the servo timing signals C and D do not change in shape or output even if the track position of the linear recording track TCn + 1 changes, The incoming servo signals An + 1 and An + 2 can be used as timing signals that are accurately identified or captured.
In addition, since the servo timing signals C and D are arranged before and after the servo pattern 27, the tape-like recording medium 1 can cope with bidirectional traveling in the forward and reverse directions. It goes without saying that the servo ID signal may be included in the servo timing signals C and D in the identification signals Bn to Bn + 3,.
[0045]
Further, FIG. 19 shows a modified example of the servo pattern described with reference to FIG.
That is, first, servo signals An to An + 3,... And Bn to Bn + 3,... Are recorded on the servo track L5 to form a servo pattern 29, and then servo signals An to An + 3,. Servo signals Cn to Cn + 3,... And Dn to Dn + 3,... Are recorded between the servo pattern 31 and the servo pattern 29 in parallel and nested, and the servo patterns 29 and 31 are distinguished from each other. The signal widths of the servo tracks L5 and L6 are changed.
In such servo patterns 29 and 31, when the tape-like recording medium 1 travels in the forward direction, when the linear recording track TCn + 2 is traced by the reproducing head, if the target identification signal is Dn + 1, the timing mark is first displayed. If the signal Dn appears but is ignored and the next timing mark signal Dn + 1 is detected and collated, the servo signals paired therewith are An + 2 and Cn + 2, which are delayed by T time. Perform detection.
When the tape-like recording medium 1 travels in the opposite direction and is detected from the linear recording track TCn, when the target identification signal is set to Bn, the identification signal Bn is first received, but the identification signal Bn + 1 is ignored. have.
When the identification signal Bn + 1 is confirmed, the servo signal paired with the identification signal Bn + 1 is Cn and An, which is delayed by T time.
[0046]
As described above, the method for recording the servo patterns 7 to 31 with the fixed head and the helical rotary head has been described. However, the recorded servo patterns 7 to 31 are the same as the patterns 7 to 19 recorded with the fixed head. The patterns 21 to 31 recorded by the mold rotary head are also similar to each other. Therefore, the operation explanation is the same as each other.
Therefore, a servo pattern detection method for detecting servo patterns 7 to 31 recorded by a fixed head or a helical rotary head will be described below.
[0047]
FIG. 20 is a diagram showing an embodiment of a servo pattern detection method according to the present invention.
In FIG. 20, on the tape-shaped recording medium 1, linear recording tracks TCn to TCn + 3 are defined in advance over the entire length in the longitudinal direction, and any one of the servo patterns 7 to 31 is recorded and formed by the above-described method.
In FIG. 20, a modified example of the servo pattern 9 including the servo signals An to An + 3 and the identification signals Bn to Bn + 3 is shown in a simplified manner, and digital data is recorded between the servo patterns 9.
On the traveling path of the tape-shaped recording medium 1, a block head 33 having a multi-channel configuration in which a number of unit reproducing heads CH1, CH2, CH3, CH4,... Corresponding to the linear recording tracks TCn to TCn + 3,. Are arranged in a direction perpendicular to the running direction of the recording medium 1, and the block head 33 is supported by the chassis of the electronic device by support means (not shown) so as to be able to contact the entire width of the recording medium 1. It has become.
As will be described later, the block head 33 is supported by support means so that the displacement can be finely adjusted in the direction perpendicular to the running direction of the tape-shaped recording medium 1.
The unit reproducing heads CH1 to CH4,... Have uniform characteristics, and the head gap extends in a direction perpendicular to the running direction of the tape-like recording medium 1 and overlaps the linear recording tracks TCn to TCn + 3,. The blocks are distributed and distributed at various position intervals.
Each unit reproducing head CH1 to CH4,... Is connected to a reproducing signal processing unit 35 for decoding, storing, and other signal processing of reproducing signals, that is, servo signals, identification signals, and servo timing signals.
[0048]
When the tape-like recording medium 1 is run and the linear recording tracks TCn to TCn + 4,... Are traced by the unit reproducing heads CH1 to CH4,... Of the block head 33, the servo pattern 9 recorded according to the present invention described above is obtained. Since the recording is performed obliquely with respect to the traveling path of the tape-like recording medium 1, the unit reproducing head CH1 of the track TCn and the unit reproducing head CH4 of the track TCn + 4 sequentially reach the unit reproducing head CH4 with a certain time interval T. Servo signals will be detected.
That is, as shown in FIG. 21, the reproduction signal processing unit 35 controls the block head 33, the unit reproduction head CH1 detects the servo signal, and the adjacent unit reproduction head CH2 receives the servo signal after a certain time T. Then, when the next unit reproducing head CH3 detects the servo signal and reaches the terminal unit reproducing head CH4 at the end, it returns to the first unit reproducing head CH1 and traces the servo signal.
[0049]
In this way, the head block 33 can obtain servo signals in a chain, and can detect as many servo signals as the number of unit reproducing heads CH1 to CH4,... (Head channels) with one servo pattern 9. If the sampling frequency of detection is increased, the detection response characteristic of the servo signal can be improved.
Further, considering the unit of the head block 33, even if the information amount of the servo signal and the identification signal reproduced by the individual unit reproducing heads CH1 to CH4,.
That is, the reproduction signal processing unit 35 temporarily records the servo signal and the identification signal reproduced by the unit reproduction heads CH1 to CH4,... And the circulation information for one cycle of the unit reproduction heads CH1 to CH4,. If one piece of information is assembled and output, the amount of information of the output signal with the head block 33 as one unit increases.
If the identification signal reproduced by each of the unit reproducing heads CH1 to CH4,... Has 5 bit ID information, 5 × 4 20 bit information can be detected in units of the head block 33. An output signal in which the detection signal detected by circulating once in 33 units is one unit becomes an identification signal having a 20-bit configuration.
In this case, the individual ID information of 5 bits possessed by each identification signal is 20 bits of ID information by combining four sets of ID information separated by T in terms of time axis and separated by m from the number of servo signals. Therefore, the identification signal is recorded in accordance with this rule.
[0050]
The total number of tracks on the tape-shaped recording medium 1 is (4 × m). Since the head block 33 performs recording and reproduction at m locations, it is only necessary to identify m identification signals. Since this is assigned to 20-bit information and the others are assigned to the block address in the running direction and its ECC, a large amount of information can be packed even if the information amount of each servo signal is reduced.
In addition, since all of the servo signals and the identification signals are not generated at the same time and are not generated at the same time, the reproduction signal processing unit 35 described above has one circuit and processing unit for detecting and decoding the servo signals and the identification signals. It is possible to switch identification signals generated by individual unit reproducing heads CH1 to CH4,... In a time series in a single decoder, etc., using a circuit or software with reduced scale. Detection and servo control can be realized.
In addition, by arranging the servo patterns 7 to 31 as described above, the servo ID signal and the servo signal can be detected at regular intervals even during tracking search. High-speed search is also possible.
[0051]
Further, since the amount of information that is the number of heads times the number of bits of the identification signal for each of the unit reproducing heads CH1 to CH4,... Can be obtained, the track address and the tape longitudinal address can be distributed and recorded in each identification signal. The code configuration can be improved.
This means that when the amount of information increases, a code that can correct detection errors due to dropouts and output fluctuations can also be added. Servo signals are distributed in the width and longitudinal directions. An error management system that is resistant to technical defects can be constructed.
This makes it possible to centrally manage information such as track addresses and addresses in the longitudinal direction of the tape, increasing the apparent sampling frequency for servo signal detection to increase servo responsiveness, servo ID signal compression, and errors It can also contribute to the improvement of processing performance.
Such an effect is due to the characteristics of the servo pattern recording method according to the present invention described above.
Further, since the servo pattern 9 according to the present invention described above includes, for example, m linear recording tracks between adjacent linear recording tracks TCn to TCn + 4, when all the linear recording tracks are considered, the head block 33 can trace them. The total number of tracks is 4 × m.
In order to trace all the linear recording tracks, the head block 33 is controlled to be displaced in the width direction of the tape-like recording medium 1 and is tracked on the adjacent linear recording tracks, and each servo signal or identification is separated by m. The signal (track) may be covered and configured to be traceable.
[0052]
In FIG. 21 in which the unit reproducing heads CH1 and CH2 are enlarged, first, when the unit reproducing head CH1 detects and passes a servo signal corresponding to the linear recording track TCn, it traces on m linear recording tracks TCn + 1. The unit reproducing head CH2 detects a servo signal corresponding to the unit reproducing head CH2, and then moves to the unit reproducing heads CH3 and CH4, and returns to the unit reproducing head CH1 shown in FIG.
For the displacement control of the head block 33, for example, the reproduction signal processing unit 35 detects and decodes the identification signal, creates a displacement correction signal based on the detection signal, and moves the block head 33 in FIG. It is performed by displacing to a track or a linear recording track that is skipped by a predetermined number.
A method of applying servo in a case where the total number of linear recording tracks is 4 × m in the head block 33 having the four head configuration will be described. First, the unit reproducing head CH1 has a track No. When the position is 1, the unit reproducing head CH2 has a track No. Is m + 1, the unit reproducing head CH3 is 2m + 1, and the unit reproducing head CH4 is 3m + 1.
Therefore, the servo signal is detected by the track No. to which each head is a combination target. Servo signals are detected and servos are applied so that each position error becomes zero (detection is performed at regular intervals). The unit reproducing head CH1 has a track No. In the case of position 2, track numbers of +1 are +2 respectively. And the unit reproducing head CH1 is the track No. When m, the unit playback head CH2 is m + m, the unit playback head CH3 is 2m + m, and the unit playback head CH4 is 3m + m. Is a combination. These relationships are established when the distance between the multichannel heads and the distance between tracks on the tape-shaped recording medium are equal.
[0053]
In the present invention, the block head 33 is not limited to a configuration in which the block head 33 is supported in a direction orthogonal to the traveling direction of the tape-shaped recording medium 1. It is possible to achieve the purpose.
In the configuration shown in FIG. 20 described above, one block head 33 is arranged so as to reach the entire width of the tape-shaped recording medium 1, but the present invention is not limited thereto.
[0054]
For example, as shown in FIG. 22, linear recording tracks TCn to TCn + 4 are tape-shaped with a width of about ½ to ¼ of the width in the direction orthogonal to the running direction of the tape-shaped recording medium 1. A configuration in which the block head 37 defined in the recording medium 1 and having the unit reproducing heads CH1 to CH4 is brought into contact with an area of about 1/2 to 1/4 of the tape-shaped recording medium 1 is also possible.
In such a configuration, in order to continuously detect the servo signal, it is necessary to detect the servo signal of the next servo pattern 9 when the cover area of the block head 37 is about to be exceeded.
That is, when the terminal unit reproducing head CH4 detects the servo signal, the servo signal of the next servo pattern 9 is recorded so that the unit reproducing head CH1 detects the servo signal. That is, the recording line interval of the servo pattern 9 is reduced by half, and when the entire width of the tape-like recording medium 1 is viewed across, two servo patterns 9 are recorded.
Therefore, if the head arrangement of the block head 37 is 1/4 of the width of the tape-like recording medium 1, the servo pattern interval becomes 1/4, so that the interval between the unit reproducing heads CH1 to CH4 and the servo signal interval. The adjustment of the recording interval may be adjusted by the recording angle of the servo pattern 9, for example.
A system in which the unit reproducing heads CH1 to CH4 always detect the adjacent two servo patterns 9 and 9 by narrowing the interval is also possible. In that case, the sampling frequency is doubled, the response speed is increased, and the stability against defects is also increased.
Of course, when there are a plurality of servo patterns 9 in the width direction of the tape-like recording medium 1, the helical rotary head can be used habitually if it can be identified when recording the identification signal, but it is recorded with a fixed head. In this case, the same identification code must be used.
In this case, a sensor for detecting the position of the block heads 33 and 37 is provided, and the identification signal can be identified by using the sensor signal and the identification signal in combination, and a method of adding an identification code on the servo pattern 9 Is also possible.
[0055]
【The invention's effect】
As described above, the first configuration according to the servo pattern recording method of the present invention includes the recording head having a track width wider than the recording width of the tape-shaped recording medium and recording the servo signal, and the tape-shaped recording medium. A tape-shaped recording medium is used for each recording timing period using an erasing head which has a wider track width than the recording width of the recording head and is arranged on the subsequent row at a predetermined angle with respect to the recording head. Since the servo signal is recorded on the tape and the servo signal is erased by the erase head at predetermined erase timing intervals, a servo pattern is formed in an oblique direction with respect to the width direction of the tape-shaped recording medium. It is possible to record a fine servo pattern with high accuracy and high speed by the method and configuration.
Also, since the servo pattern is formed by a fixed recording head or erasing head, high-speed recording formation is possible, and the servo pattern may be spatially and time-sequentially distributed on the tape-shaped recording medium to reduce the recording area. It is possible to maintain a good reproduction response speed.
[0056]
In the first configuration, when the recording head is used as a fixed head, servo patterns can be recorded at a higher speed. In the configuration where the recording head is used as a rotary head, individual contents and continuous recording are possible. Recording of an identification signal having an address is simplified.
In the first configuration, the recording head partially records a special signal different from the servo signal, and in the configuration in which the special signal is included in the servo pattern, in addition to the effects described above, the linear recording track is traced. Tracking correction of the reproducing head and the data recording head can be easily performed.
Furthermore, in the first configuration, the special signal is a servo identification signal for identifying the front and rear, or a servo timing signal indicating the detection timing. In addition to the effects described above, the servo signal and the identification signal are accurately detected. it can.
Further, in the first configuration, in the configuration in which the servo pattern is formed so that the signal forming the servo pattern extends over a plurality of linear recording tracks, similarly, in addition to the above-described effects, a servo signal, an identification signal, etc. It can be detected accurately.
[0057]
In the second configuration related to the servo pattern recording method of the present invention, a rotary head that rotates obliquely with respect to the traveling direction of the tape-shaped recording medium is disposed in the traveling path, and with respect to the width direction of the tape-shaped recording medium, Since the servo signal is recorded on the tape-like recording medium by the rotary head every predetermined recording timing period, and the servo pattern is formed obliquely at recording timing intervals in the track direction of the rotary head, a relatively simple method and configuration Makes it possible to record fine servo patterns with high accuracy and high speed, eliminates the need for an erasing head, further simplifies the configuration, enables high-speed recording formation, and saves space in the recording area. It is possible to maintain a high playback response speed.
[0058]
In the second configuration, in the configuration in which a special signal different from the servo signal is recorded by the recording head and the special signal is included in the servo pattern, in addition to the above-described effect, reproduction for tracing the linear recording track is performed. Tracking correction of the head and data recording head can be easily performed.
Further, in the second configuration, in the configuration in which the special signal is a servo identification signal for identifying front and rear or a servo timing signal indicating detection timing, in addition to the above-described effects, the servo signal and the identification signal are accurately Can be detected.
[0059]
In the servo pattern detection method according to the present invention, a plurality of reproducing heads are arranged in accordance with the linear recording track so as to intersect the arrangement direction of the servo patterns arranged obliquely with respect to the width direction of the tape-shaped recording medium, Along with the trace on the linear recording track by the reproducing head, the servo pattern is sequentially and cyclically detected by a plurality of reproducing heads corresponding to the order of appearance of the servo pattern, so that fine servo pattern recording on the linear recording track is performed. Can be easily detected.
In addition, in the servo pattern detection method of the present invention, if an output signal with one unit of the detection signal detected from the servo pattern is obtained by one cycle, in addition to the above-described effect, reproduction is performed on each linear recording track. It is possible to reduce the amount of information such as servo signals to be recorded, and servo signal recording and reproduction, and further a signal processing circuit is simplified.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a servo pattern recording method of the present invention.
FIG. 2 is a diagram illustrating a servo pattern recording method according to the present invention.
FIG. 3 is a waveform diagram showing a reproduction waveform by a servo pattern obtained by the servo pattern recording method of the present invention.
FIG. 4 is a diagram illustrating another embodiment according to the servo pattern recording method of the present invention.
5 is a diagram for explaining a servo pattern recording method related to FIG. 4; FIG.
6 is a waveform diagram showing a reproduction waveform by a servo pattern obtained by the servo pattern recording method of FIG.
FIG. 7 is a diagram for explaining another embodiment of a servo pattern recording method according to the present invention.
8 is a waveform diagram showing a reproduction waveform by a servo pattern obtained by the servo pattern recording method of FIG.
FIG. 9 is a diagram for explaining another embodiment of a servo pattern recording method according to the present invention.
FIG. 10 is a diagram for explaining another embodiment of a servo pattern recording method according to the present invention.
FIG. 11 is a diagram showing another embodiment of the servo pattern recording method of the present invention.
FIG. 12 is a diagram showing another embodiment of the servo pattern recording method of the present invention.
FIG. 13 is a diagram showing another embodiment of the servo pattern recording method of the present invention.
14 is a reproduction waveform diagram by a servo pattern obtained by the servo pattern recording method of FIG.
FIG. 15 is a diagram showing another embodiment of the servo pattern recording method of the present invention.
16 is a reproduction waveform diagram by a servo pattern obtained by the servo pattern recording method of FIG.
FIG. 17 is a diagram showing another embodiment of the servo pattern recording method of the present invention.
18 is a reproduction waveform diagram by a servo pattern obtained by the servo pattern recording method of FIG.
FIG. 19 is a diagram showing another embodiment of the servo pattern recording method of the present invention.
FIG. 20 is a diagram showing an embodiment of a servo pattern detection method of the present invention.
FIG. 21 is an enlarged view of a main part showing an embodiment of a servo pattern detection method of the present invention.
FIG. 22 is a diagram showing another embodiment of the servo pattern detection method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Tape-like recording medium, 3, 15 ... Recording head, 5, 17 ... Erase head (recording head), 7, 9, 11, 13, 19, 21, 23, 25, 27, 29, 31 ... ... Servo pattern, 33, 37 ... Block head, 35 ... Reproduction signal processing unit, An, An + 1, An + 2, An + 3 ... Servo signal, Bn, Bn + 1, Bn + 2, Bn + 3 ... Identification signal, CH1, CH2, CH3, CH4: Unit reproducing head (reproducing head), Cn, Cn + 1, Cn + 2, Cn + 3 ... Servo signals C, D, L1, L2, L3, L4, L5, L6 ... Servo pattern track, TCn, TCn + 1, TCn + 2, TCn + 3 ... Linear recording track, X, Y ... Servo timing mark signal

Claims (13)

In a servo pattern recording method for recording a servo pattern for linear recording track control on a tape-shaped recording medium,
A recording head that records a servo signal having a track width wider than the recording width of the tape-shaped recording medium is disposed in the traveling path of the tape-shaped recording medium,
An erasing head having a track width wider than the recording width of the tape-shaped recording medium is disposed in the traveling path on the subsequent side with a predetermined angle with respect to the recording head,
Servo signals recorded on the tape-shaped recording medium by the recording head every predetermined recording timing period are erased by the erasing head at predetermined erasing timing intervals, and are oblique to the width direction of the tape-shaped recording medium. A servo pattern recording method, wherein the servo pattern is formed in the direction at the unerasing timing interval. 2. The servo pattern recording method according to claim 1, wherein the recording head is a fixed head. 2. The servo pattern recording method according to claim 1, wherein the recording head is a rotary head. 4. The servo pattern recording method according to claim 1, wherein the recording head partially records a special signal different from the servo signal, and includes the special signal in the servo pattern. 5. The servo pattern recording method according to claim 4, wherein the special signal is a servo identification signal for identifying front and rear. 5. The servo pattern recording method according to claim 4, wherein the special signal is a servo timing signal indicating a detection timing. 7. The servo pattern according to claim 1, wherein the servo pattern is left unerased by the erasing head so that a signal for forming the servo pattern extends over the plurality of linear recording tracks. Recording method. In a servo pattern recording method for recording a servo pattern for linear recording track control on a tape-shaped recording medium,
A rotating head that rotates obliquely with respect to the traveling direction of the tape-shaped recording medium is disposed in the traveling path;
By recording a servo signal on the tape-like recording medium at a predetermined recording timing period by the rotary head with respect to the width direction of the tape-like recording medium, the tape-like recording medium is inclined at the recording timing interval in the track direction of the rotary head. A servo pattern recording method comprising forming the servo pattern. 9. The servo pattern recording method according to claim 8, wherein the recording head partially records a special signal different from the servo signal, and includes the special signal in the servo pattern. The servo pattern recording method according to claim 9, wherein the special signal is a servo identification signal for identifying front and rear. The servo pattern recording method according to claim 9, wherein the special signal is a servo timing signal indicating a detection timing. In a servo pattern detection method for detecting servo patterns for linear recording track control recorded on a plurality of linear recording tracks on a tape-shaped recording medium,
A plurality of reproducing heads are arranged so as to intersect with an arrangement direction of servo patterns arranged obliquely with respect to the width direction of the tape-shaped recording medium and in accordance with the linear recording track, and A servo pattern detection method, wherein the servo patterns are sequentially and cyclically detected by a plurality of the reproducing heads in correspondence with the appearance order of the servo patterns in accordance with a trace on a recording track. 13. The servo pattern detection method according to claim 12, wherein an output signal with a detection signal detected from the servo pattern as one unit is obtained by one cycle.

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