JP2019197606A - Magnetic tape reading device and magnetic tape reading method - Google Patents

Abstract

To provide a magnetic tape reading device and a magnetic tape reading method capable of suppressing a decrease in reliability of data read from a reading target track, as compared with a case where the data is read from the reading target track by only a single reading element.SOLUTION: A magnetic tape reading device 10 includes: a reading element unit 38 that has a plurality of reading elements arranged in close proximity status and respectively reads data from a specific track area including a reading target track among the track areas included in the magnetic tape; and an extracting portion 62 that extracts the data derived from the reading target track from the read result by performing waveform equalization processing corresponding to the amount of positional deviation between the magnetic tape and the reading element unit 38 for each read result for each reading element.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a magnetic tape reader and a magnetic tape reading method.

  Patent Document 1 discloses a read head in which each of a plurality of reading elements for a magnetic storage medium reads a plurality of tracks simultaneously from the storage medium by using a plurality of active regions.

  Patent Document 2 includes a first magnetic layer whose magnetization direction is fixed, and a second magnetic layer which is provided opposite to the first magnetic layer with an insulating layer interposed therebetween and whose magnetization direction is not fixed. A magnetic head including a plurality of reproducing elements each having the same is disclosed. In the magnetic head described in Patent Document 2, at least two of the plurality of reproducing elements are arranged such that each of the first magnetic layer and the second magnetic layer crosses an arbitrary straight line, and The magnetization directions of one magnetic substance are different from each other.

  Patent Document 3 discloses a magnetic signal reproducing apparatus including a reproducing head, a positional deviation amount calculation unit, and an output value calculation unit. In the magnetic signal reproducing apparatus described in Patent Document 3, the reproducing head has a plurality of reproducing elements arranged in the width direction of the track on the disk, and a burst signal recorded for each track is positioned on the track. Playback is performed with a plurality of playback elements. In addition, the reproducing head simultaneously reproduces the data signal recorded for each data track formed in the width direction of one track by two or more reproducing elements located on the data track.

  In the magnetic signal reproducing apparatus described in Patent Document 3, the misregistration amount calculation unit calculates the misregistration amount of the reproducing head with respect to the center of the track at the time of signal reproduction from the burst signal recorded on the track. Further, in the magnetic signal reproducing apparatus described in Patent Document 3, the output value calculating unit determines the positional relationship between the data track and two or more reproducing elements located on the data track based on the positional error corresponding to the positional deviation amount of the reproducing head. Determine. The output value calculation unit weights and synthesizes the data signals reproduced simultaneously for each data track based on the determination result, and calculates the output value of the data track.

  Patent Document 4 discloses a reproducing apparatus based on a helical scan. In the reproduction apparatus described in Patent Document 4, the channel matrix estimation unit is based on a plurality of channel matrices obtained as a result of channel estimation calculation from reproduction signals of separation patterns in a plurality of consecutive preambles with data sandwiched therebetween. Next, a variable channel matrix is estimated within the interval of the data. Then, the signal separation calculation unit separates the reproduction signal for each track from the reproduction signal for one unit using the variable channel matrix estimated by the channel matrix estimation unit.

US Pat. No. 7,755,863 B2 JP 2016-110680 A JP 2011-134372 A JP 2008-282501 A

  However, Patent Document 1 does not disclose a specific method for utilizing the read head. The techniques described in Patent Document 2 and Patent Document 3 are all based on the premise that data is read from a disk medium. A plurality of reproducing elements and tracks are formed by an inner diameter portion and an outer diameter portion of the disk medium. The position relative to the center changes. Therefore, it is difficult to arrange each of the plurality of reproducing elements so as not to be displaced with respect to all the tracks. In the technique described in Patent Document 3, since the servo pattern and the data are written on the same track, it is difficult to read the data correctly when a steep vibration occurs. Furthermore, the technique described in Patent Document 4 is based on the assumption of helical scanning, and it is difficult to read the servo signal from the servo pattern and the data from the reading target track synchronously as in the linear scanning method. It is.

  By the way, in the example shown in FIG. 14, the elongated reading head 200 includes a plurality of reading elements 202 along the longitudinal direction. A plurality of tracks 206 are formed on the magnetic tape 204. The read head 200 is arranged so that the longitudinal direction thereof coincides with the width direction of the magnetic tape 204. Each of the plurality of reading elements 202 is assigned to each of the plurality of tracks 206 in a one-to-one relationship, and reads data from the tracks 206 at the opposing positions.

  However, the magnetic tape 204 expands and contracts due to changes in time, environment, tension, and the like. When the magnetic tape expands and contracts in the width direction of the magnetic tape 204, the center of the reading element 202 arranged at both ends in the longitudinal direction is shifted from the center of the track 206 in the reading head 200. When the magnetic tape 204 is deformed by expanding and contracting in the width direction, the reading element 202 closer to both ends of the reading head 200 among the plurality of reading elements 202 is particularly affected by off-track. In order to reduce the influence of off-track, for example, a method of giving a margin to the width of the track 206 can be considered. However, as the width of the track 206 is increased, the recording density of data in the magnetic tape 204 becomes lower. End up.

  As an example, as shown in FIG. 15, the read head 200 is provided with a servo element 208. A servo pattern previously applied to the magnetic tape 204 along the traveling direction of the magnetic tape 204 is read by the servo element 208. Then, from the servo signal obtained by reading the servo pattern by the servo element 208, a control device (not shown) determines which position on the magnetic tape 204 the reading element 202 is traveling at regular time intervals. Identified. Thus, the PES (Position Error Signal) in the width direction of the magnetic tape 204 is detected by the control device.

  As described above, when the travel position of the reading element 202 is specified by the control device, feedback control is performed on the read head actuator (not shown) by the control device based on the specified travel position. Thus, tracking in the width direction of the magnetic tape 204 is realized.

  However, even if tracking is performed, steep vibrations and high-frequency components of jitter, etc., cause PES to increase, leading to a decrease in the reliability of data read from the read target track.

  One embodiment of the present invention suppresses a decrease in the reliability of data read from a read target track by a linear scan method, compared to a case where data is read from the read target track by a single scanning element alone. An object of the present invention is to provide a magnetic tape reading apparatus and a magnetic tape reading method that can be used.

  In order to achieve the above object, the magnetic tape reader according to the first aspect of the present invention reads each data from a specific track area including a track to be read out of the track areas included in the magnetic tape, and is in an adjacent state. By applying a waveform equalization process according to the amount of positional deviation between the magnetic tape and the reading element unit to each of the reading element unit having a plurality of reading elements arranged at And an extraction unit that extracts data derived from the reading target track from the reading result. Therefore, the magnetic tape reading apparatus according to the first aspect of the present invention reads data from the read target track by the linear scan method as compared with the case where data is read from the read target track by the single scanning element alone. A decrease in data reliability can be suppressed.

  In the magnetic tape reader according to the second aspect of the present invention, a part of each of the plurality of reading elements overlaps in the traveling direction of the magnetic tape. Therefore, in the magnetic tape reading device according to the second aspect of the present invention, the data read from the reading target track by the linear scan method is compared with the case where the reading elements are entirely overlapped with each other in the traveling direction of the magnetic tape. The reliability of can be increased.

  In the magnetic tape reading device according to the third aspect of the present invention, the specific track area is an area including a read target track and an adjacent track adjacent to the read target track, and each of the plurality of reading elements is magnetic. When the positional relationship with the tape changes, both the reading target track and the adjacent track are straddled. Therefore, in the magnetic tape reading device according to the third aspect of the present invention, one reading element has a reading target track in the width direction of the magnetic tape as compared with a case where data is read from the reading target track only by a single reading element. The noise component generated by entering the adjacent track from the head can be reduced by using the reading result by another reading element entering the adjacent track from the track to be read in the width direction of the magnetic tape.

  In the magnetic tape reader according to the fourth aspect of the present invention, the plurality of reading elements are arranged side by side in the state of being close to each other in the width direction of the magnetic tape. Therefore, the magnetic tape reading apparatus according to the fourth aspect of the present invention has a linear scanning method from a wide area of the reading target track as compared with the case where data is read from the reading target track by only a single reading element by the linear scanning method. Can read data.

  In the magnetic tape reader according to the fifth aspect of the present invention, the plurality of reading elements are within the track to be read in the width direction of the magnetic tape. Therefore, the magnetic tape reading apparatus according to the fifth aspect of the present invention uses a linear scanning method with a plurality of reading elements as compared with a case where a plurality of reading elements protrude from the reading target track in the width direction of the magnetic tape. It is possible to make it difficult to mix noise components from tracks adjacent to the read target track into the read data.

  In the magnetic tape reader according to the sixth aspect of the present invention, the tap coefficient used in the waveform equalization processing is determined according to the shift amount. Therefore, in the magnetic tape reading device according to the sixth aspect of the present invention, compared with the case where the tap coefficient is determined according to the parameter not related to the deviation amount, the reading target track from the adjacent track in the width direction of the magnetic tape is compared. Noise components generated by entering can be immediately reduced following the change in the positional relationship between the magnetic tape and the reading element unit.

  In the magnetic tape reader according to the seventh aspect of the present invention, the ratio of the overlapping area with the reading target track to the overlapping area with the adjacent track adjacent to the reading target track is shifted for each of the plurality of reading elements. It is specified from the quantity, and the tap coefficient is determined according to the specified ratio. Therefore, the magnetic tape reader according to the seventh aspect of the present invention uses a parameter that is not related to the ratio of the overlapping area of the reading target track and the overlapping area of the adjacent track for each of the plurality of reading elements. Compared with the case where the tap coefficient is determined accordingly, the noise component can be accurately reduced even if the positional relationship between the magnetic tape and the reading element unit changes.

  In the magnetic tape reader according to the eighth aspect of the present invention, the deviation amount is determined according to the result obtained by the servo element reading the servo pattern previously applied to the magnetic tape. Therefore, the magnetic tape reader according to the eighth aspect of the present invention can easily determine the amount of deviation compared to the case where the servo pattern is not applied to the magnetic tape.

  In the magnetic tape reading device according to the ninth aspect of the present invention, the reading operation by the reading element unit is performed in synchronization with the reading operation by the servo element. Therefore, the magnetic tape reader according to the ninth aspect of the present invention enters the read target track from the adjacent track in the width direction of the magnetic tape, as compared with the magnetic disk that cannot read the servo pattern and the data synchronously. The noise component generated in can be immediately reduced.

  In the magnetic tape reader according to the tenth aspect of the present invention, the extraction unit has a two-dimensional FIR filter, and the two-dimensional FIR filter performs a waveform equalization process on each of the read results for each reading element. By combining the results thus obtained, data derived from the read target track is extracted from the read result. Therefore, the magnetic tape reader according to the tenth aspect of the present invention can quickly extract data derived from the read target track from the read result as compared with the case where only the one-dimensional FIR filter is used.

  In the magnetic tape reader according to the eleventh aspect of the present invention, the plurality of reading elements are a pair of reading elements. Therefore, the magnetic tape reader according to the eleventh aspect of the present invention can contribute to downsizing of the reading element unit as compared with the case of using three reading elements.

  In order to achieve the above object, a magnetic tape reader according to a twelfth aspect of the present invention linearly transfers data from each of a plurality of specific track areas each including a read target track among the track areas included in the magnetic tape. A plurality of reading element units each having a plurality of reading elements that are each read in a scanning manner and arranged close to each other, and a magnetic tape for each of the reading results for each reading element for each of the plurality of reading element units And an extraction unit that extracts data derived from the read target track from the read result by performing waveform equalization processing according to the amount of positional deviation between the read element unit and the read element unit. Therefore, the magnetic tape reader according to the twelfth aspect of the present invention reads data from the read target track by the linear scan method as compared with the case where data is read from the read target track by the single scanning element alone. A decrease in data reliability can be suppressed.

  In order to achieve the above object, a magnetic tape reading method according to a thirteenth aspect of the present invention includes a reading element unit having a plurality of reading elements arranged in a state in which the plurality of reading elements are close to each other. The elements each read data from a specific track area including a reading target track among the track areas included in the magnetic tape by a linear scan method, and the extraction unit reads the magnetic tape for each of the reading results for each reading element. A magnetic tape reading method including extracting data derived from a read target track from a read result by performing a waveform equalization process according to a positional deviation amount with respect to a reading element unit.

  According to one embodiment of the present invention, the reliability of data read from a read target track by a linear scan method is reduced as compared with a case where data is read from a read target track by a single scanning element only by a linear scanning method. The effect that it can suppress is acquired.

1 is a schematic configuration diagram illustrating an example of an overall configuration of a magnetic tape reader according to an embodiment. 1 is a schematic plan view showing an example of a schematic configuration of a read head and a magnetic tape included in a magnetic tape reader according to an embodiment in plan view. It is a schematic plan view which shows an example of schematic structure of the planar view of the reading element unit and magnetic tape which concern on embodiment. 3 is a schematic plan view illustrating an example of a schematic configuration in a plan view of a track area and a reading element pair. FIG. It is a graph which shows an example of the correlation of SNR and track offset regarding each of single reading element data and the 1st synthetic data under the 1st condition. It is a graph which shows an example of the correlation of SNR and track offset regarding each of single reading element data and the 2nd synthetic data on 2nd conditions. It is a block diagram which shows an example of the principal part structure of the electric hardware of the magnetic tape reader which concerns on embodiment. It is a conceptual diagram with which it uses for description of the calculation method of deviation | shift amount. It is a flowchart which shows an example of the flow of the magnetic tape reading process which concerns on embodiment. It is a conceptual diagram with which it uses for description of the process performed with the two-dimensional FIR filter of the extraction part which concerns on embodiment. It is a schematic plan view which shows an example of the state in which the reading element unit which concerns on embodiment straddles the reading object track and the 2nd noise mixing source track. It is a schematic plan view which shows the 1st modification of the reading element unit which concerns on embodiment. It is a schematic plan view which shows the 2nd modification of the reading element unit which concerns on embodiment. It is a conceptual diagram with which it uses for description of the 1st prior art example. It is a conceptual diagram with which it uses for description of the 2nd prior art example. It is a figure which shows an example of the two-dimensional image of the reproduction | regeneration signal obtained from a single reading element.

  Hereinafter, an example of an embodiment of a magnetic tape reader according to the technique of the present disclosure will be described with reference to the accompanying drawings.

  As an example, as shown in FIG. 1, the magnetic tape reader 10 includes a magnetic tape cartridge 12, a transport device 14, a read head 16, and a control device 18.

  The magnetic tape reader 10 is a device that pulls out the magnetic tape MT from the magnetic tape cartridge 12 and reads data from the pulled-out magnetic tape MT using the read head 16 by a linear scan method. Note that in the embodiment of the present disclosure, reading data refers to data reproduction in other words.

  The control device 18 controls the entire magnetic tape reader 10. In the embodiment of the present disclosure, the control device 18 is realized by an ASIC (Application Specific Integrated Circuit), but the technology of the present disclosure is not limited thereto. For example, the control device 18 may be realized by an FPGA (Field-Programmable Gate Array). The control device 18 may be realized by a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). Moreover, you may make it implement | achieve combining 2 or more of AISC, FPGA, and a computer.

  The transport device 14 is a device that selectively transports the magnetic tape MT in the forward direction and the reverse direction, and includes a feed motor 20, a take-up reel 22, a take-up motor 24, a plurality of guide rollers GR, and a control device 18. ing.

  A cartridge reel CR is provided in the magnetic tape cartridge 12. A magnetic tape MT is wound around the cartridge reel CR. The delivery motor 20 rotates the cartridge reel CR in the magnetic tape cartridge 12 under the control of the control device 18. The control device 18 controls the rotation direction, the rotation speed, the rotation torque, and the like of the cartridge reel CR by controlling the delivery motor 20.

  When the magnetic tape MT is taken up by the take-up reel 22, the controller 18 rotates the feeding motor 20 so that the magnetic tape MT travels in the forward direction. The rotational speed, rotational torque, and the like of the delivery motor 20 are adjusted according to the speed of the magnetic tape MT taken up by the take-up reel 22.

  The take-up motor 24 rotates the take-up reel 22 under the control of the control device 18. The control device 18 controls the take-up motor 24 to control the rotation direction, the rotation speed, the rotation torque, and the like of the take-up reel 22.

  When the magnetic tape MT is taken up by the take-up reel 22, the control device 18 rotates the take-up motor 24 so that the magnetic tape MT travels in the forward direction. The rotational speed and rotational torque of the take-up motor 24 are adjusted according to the speed of the magnetic tape MT taken up by the take-up reel 22.

  In this way, by adjusting the rotational speed, the rotational torque, and the like of each of the delivery motor 20 and the take-up motor 24, a tension within a predetermined range is applied to the magnetic tape MT. Here, “within a predetermined range” means, for example, a tension range obtained by computer simulation and / or a test by an actual machine as a tension range in which data can be read from the magnetic tape MT by the reading head 16.

  When the magnetic tape MT is rewound onto the cartridge reel CR, the control device 18 rotates the feeding motor 20 and the take-up motor 24 so that the magnetic tape MT travels in the reverse direction.

  In the embodiment of the present disclosure, the tension of the magnetic tape MT is controlled by controlling the rotation speed, the rotation torque, and the like of the feed motor 20 and the take-up motor 24, but the technology of the present disclosure is not limited to this. For example, the tension of the magnetic tape MT may be controlled using a dancer roller, or may be controlled by pulling the magnetic tape MT into the vacuum chamber.

  Each of the plurality of guide rollers GR is a roller for guiding the magnetic tape MT. The travel path of the magnetic tape MT is determined by arranging a plurality of guide rollers GR in positions that straddle the read head 16 between the magnetic tape cartridge 12 and the take-up reel 22.

  The reading head 16 includes a reading unit 26 and a holder 28. The reading unit 26 is held by a holder 28 so as to come into contact with the running magnetic tape MT.

  As an example, as shown in FIG. 2, the magnetic tape MT includes a track area 30 and a servo pattern 32. The servo pattern 32 is a pattern used for detecting the position of the read head 16 with respect to the magnetic tape MT. The servo pattern 32 includes a first oblique line 32A having a first predetermined angle (for example, 95 degrees) and a second oblique line 32B having a second predetermined angle (for example, 85 degrees) at both ends of the tape width direction. These patterns are alternately arranged at a constant pitch along the traveling direction. Here, the “tape width direction” refers to the width direction of the magnetic tape MT.

  The track area 30 is an area where data to be read is written, and is formed at the center of the magnetic tape MT in the tape width direction. Here, the “central portion in the tape width direction” refers to a region between the servo pattern 32 at one end and the servo pattern 32 at the other end of the magnetic tape MT, for example. In the following, for convenience of explanation, the “traveling direction of the magnetic tape MT” is simply referred to as “traveling direction”.

  The reading unit 26 includes a servo element pair 36 and a plurality of reading element units 38. The holder 28 is formed in a long shape in the tape width direction, and the total length in the longitudinal direction of the holder 28 is longer than the width of the magnetic tape MT. The servo element pairs 36 are disposed at both ends in the longitudinal direction of the holder 28, and the plurality of reading element units 38 are disposed at the center in the longitudinal direction of the holder 28.

  The servo element pair 36 includes servo elements 36A and 36B. The servo element 36A is arranged at a position facing the servo pattern 32 at one end of the magnetic tape MT in the tape width direction, and the servo element 36B is arranged at the servo pattern 32 at the other end of the magnetic tape MT in the tape width direction. It is arranged at the opposite position.

  In the holder 28, a plurality of reading element units 38 are arranged along the tape width direction between the servo elements 36A and 36B. The track area 30 is provided with a plurality of tracks at equal intervals in the tape width direction, and each of the plurality of reading element units 38 faces each track in the track area 30 in the default state of the magnetic tape reader 10. Are arranged.

  Therefore, the reading unit 26 and the magnetic tape MT relatively move linearly along the longitudinal direction of the magnetic tape MT, so that the data of each track in the track area 30 is stored in the plurality of reading element units 38. Each reading element unit 38 corresponding to the position is read by the linear scanning method. In the linear scan method, the servo pattern 32 is read by the servo element pair 36 in synchronization with the reading operation of the reading element unit 38. That is, in the linear scan method according to the embodiment of the present disclosure, reading from the magnetic tape MT is performed in parallel by the plurality of reading element units 38 and the servo element pairs 36.

  Here, the above “each track in the track area 30” refers to “each of a plurality of specific track areas each including a read target track among the track areas included in the magnetic tape” according to the technique of the present disclosure. Refers to the tracks contained in

  The default state of the magnetic tape reader 10 indicates a state where the magnetic tape MT is not deformed and the positional relationship between the magnetic tape MT and the read head 16 is in a correct positional relationship. Here, the correct positional relationship refers to, for example, a positional relationship in which the center in the tape width direction of the magnetic tape MT and the center in the longitudinal direction of the read head 16 coincide.

  Since each of the plurality of reading element units 38 has the same configuration, one of the plurality of reading element units 38 will be described below as an example for convenience of explanation. As an example, as illustrated in FIG. 3, the reading element unit 38 includes a pair of reading elements. In the example shown in FIG. 3, the pair of reading elements refers to a first reading element 40 and a second reading element 42. Each of the first reading element 40 and the second reading element 42 reads data from the specific track area 31 including the reading target track 30 </ b> A in the track area 30.

  In the example shown in FIG. 3, one specific track area 31 is shown for convenience of explanation. Actually, however, a plurality of specific track areas 31 exist in the track area 30, and each specific track area 31 exists. 31 includes a read target track 30A. One reading element unit 38 is assigned to each of the plurality of specific track areas 31. Specifically, one reading element unit 38 is allocated to each reading target track 30 </ b> A of the plurality of specific track areas 31.

  The specific track area 31 refers to three adjacent tracks. The first track of the three adjacent tracks is the read target track 30 </ b> A in the track area 30. The second of the three adjacent tracks is a first noise contamination source track 30B which is one of the adjacent tracks adjacent to the read target track 30A. The third of the three adjacent tracks is a second noise mixing source track 30C that is one of the adjacent tracks adjacent to the read target track 30A. The read target track 30 </ b> A is a track at a position facing the reading element unit 38 in the track region 30. In other words, the reading target track 30 </ b> A refers to a track that is a data reading target by the reading element unit 38.

  The first noise mixing source track 30B is adjacent to one side in the tape width direction with respect to the reading target track 30A, and is a track serving as a mixing source of noise mixed in the data read from the reading target track 30A. is there. The second noise mixing source track 30C is adjacent to the reading target track 30A on the other side in the tape width direction, and serves as a mixing source of noise mixed in the data read from the reading target track 30A. is there. In the following, for convenience of explanation, when there is no need to distinguish between the first noise mixing source track 30B and the second noise mixing source track 30C, they are referred to as “adjacent tracks” without reference numerals.

  In the embodiment of the present disclosure, a plurality of specific track areas 31 are arranged at regular intervals in the tape width direction in the track area 30. For example, in the track area 30, 32 specific track areas 31 are arranged at regular intervals in the tape width direction, and one read element unit 38 is assigned to each specific track area 31.

  The first reading element 40 and the second reading element 42 are arranged in a state of being close to each other in the traveling direction and partially overlapping in the traveling direction. In the default state of the magnetic tape reader 10, the first reading element 40 is disposed at a position straddling the reading target track 30A and the first noise mixing source track 30B. In the default state of the magnetic tape reader 10, the second reading element 42 is disposed at a position straddling the reading target track 30A and the first noise mixing source track 30B.

  In the default state of the magnetic tape reader 10, the area of the portion of the first reading element 40 that faces the reading target track 30 </ b> A in plan view is the first noise mixing in the first reading element 40. It is larger than the area of the portion facing the source track 30B. On the other hand, in the default state of the magnetic tape reader 10, the area of the portion of the second reading element 42 that faces the first noise-mixing source track 30 </ b> B in the plan view is the first reading element 40. Is larger than the area of the portion facing the read target track 30A.

  The data read by the first reading element 40 is subjected to waveform equalization processing by a first equalizer 70 (see FIG. 7) described later. The data read by the second reading element 42 is subjected to waveform equalization processing by a second equalizer 72 (see FIG. 7) described later. Each data obtained by performing waveform equalization processing by each of the first equalizer 70 and the second equalizer 72 is added by the adder 44 and synthesized.

  In the embodiment of the present disclosure, the reading element unit 38 has been described as an example in which the reading element unit 38 includes the first reading element 40 and the second reading element 42. For example, one reading element of a pair of reading elements is read. Even if only the element (hereinafter also referred to as a single reading element) is used, a signal corresponding to the reproduction signal obtained from the reading element unit 38 is obtained.

  In this case, for example, as shown in FIG. 8 as an example, the plane position on the track calculated from the servo signal obtained by the servo element pair 36 in synchronization with the reproduction signal is obtained from the reproduction signal obtained from the single reading element. Assign to. Then, by repeating this while moving the single reading element in the tape width direction, a two-dimensional image of the reproduction signal (hereinafter simply referred to as “two-dimensional image”) is obtained. Here, a reproduction signal (for example, a reproduction signal corresponding to the positions of a plurality of tracks) constituting a two-dimensional image or a part of the two-dimensional image is a signal corresponding to a reproduction signal obtained from the reading element unit 38. is there.

  FIG. 16 shows an example of a two-dimensional image of a reproduction signal obtained by using a loop tester on a looped magnetic tape MT (hereinafter also referred to as “loop tape”). Here, the loop tester refers to, for example, a device that transports a loop tape in a state of repeatedly contacting a single reading element. In order to obtain a two-dimensional image as with the loop tester, a reel tester may be used, or an actual tape drive may be used. The “reel tester” here refers to, for example, a device that transports the magnetic tape MT in a reel form.

  As described above, even if a conventional magnetic tape head that does not have a reading element unit having a plurality of reading elements mounted at close positions is used, it is possible to quantitatively evaluate the effects according to the technique of the present disclosure. It becomes. An example of an index for quantitatively evaluating the effect according to the technology of the present disclosure includes SNR (Signal-to-Noise Ratio), an error rate, and the like.

  4 to 6 show results obtained by experiments by the inventors. As an example, as shown in FIG. 4, a reading element pair 50 is disposed on the track region 49. The track area 49 is a first track 49A, a second track 49B, and a third track 49C that are adjacent to each other in the tape width direction. The reading element pair 50 is a first reading element 50A and a second reading element 50B. The first reading element 50A and the second reading element 50B are arranged at positions close to each other in the tape width direction. The first reading element 50A is disposed so as to face the second track 49B, which is the track to be read, and to fit in the second track 49B. Further, the second reading element 50B is disposed so as to face the first track 49A adjacent to one side of the second track 49B and be within the first track 49A.

  FIG. 5 shows an example of the correlation between the SNR (Signal-to-Noise Ratio) and the track offset for each of the single reading element data and the first combined data under the first condition. FIG. 6 shows an example of the correlation between the SNR and the track offset for each of the single reading element data and the second combined data under the second condition.

  Here, the single reading element data refers to data obtained by performing waveform equalization processing on the data read by the first reading element 50A, similarly to the first reading element 40 shown in FIG. Point to. The first condition refers to a condition that the reading element pitch is 700 nm (nanometer). The second condition refers to a condition where the reading element pitch is 500 nm. As shown in FIG. 4 as an example, the reading element pitch refers to a pitch in the tape width direction between the first reading element 50A and the second reading element 50B. As shown in FIG. 4 as an example, the track offset indicates a deviation amount between the center of the second track 49B in the tape width direction and the center of the first reading element 50A in the track width direction.

  The first synthesized data refers to data synthesized by adding the first waveform equalized data and the second waveform equalized data obtained respectively under the first condition. Similar to the first reading element 40 shown in FIG. 3, the first waveform equalization processed data is data obtained by performing waveform equalization processing on the data read by the first reading element 50A. Point to. Similar to the second reading element 42 shown in FIG. 3, the second waveform equalization-processed data is data obtained by performing waveform equalization processing on the data read by the second reading element 50B. Point to. The second synthesized data refers to data synthesized by adding the first waveform equalized data and the second waveform equalized data obtained respectively under the second condition.

  Comparing the SNR of the first synthesized data shown in FIG. 5 with the SNR of the second synthesized data shown in FIG. 6, the SNR of the first synthesized data has a track offset of about −0.4 μm (micrometer) to about 0.2 μm. However, the SNR of the second composite data does not drop sharply in the middle as in the SNR graph of the first composite data. Each of the SNR of the first composite data and the SNR of the second composite data is higher than the SNR of the single read element data. In particular, the SNR of the second composite data is the single read element data in the entire range of the track offset. Higher than the SNR.

  From the experimental results shown in FIGS. 5 and 6, the inventors have compared the first reading element 50 </ b> A and the second reading element 50 </ b> B in the tape width direction as compared with the case where data is read only by the first reading element 50 </ b> A. It has been found that it is preferable to read data in a state of being in close proximity to. Here, the “closed state” means, for example, that the first reading element 50A and the second reading element 50B are not in contact with each other, and the SNR is higher than the SNR of the single reading element data in the entire track offset range. Indicates a state of being arranged side by side in the tape width direction so as to increase.

  In the embodiment of the present disclosure, as illustrated in FIG. 3 as an example, in the reading element unit 38, the first reading element 40 and the second reading element 42 are partially overlapped with each other in the traveling direction. The high density of tracks included in the magnetic tape MT is realized.

  As an example, as shown in FIG. 7, the magnetic tape reader 10 includes an actuator 60, an extraction unit 62, A / D (Analog / Digital) converters 64, 66, 68, a decoding unit 69, and a computer 73. .

  The control device 18 is connected to the servo element pair 36 via an A / D converter 68. The A / D converter 68 converts the servo signal obtained by converting the analog signal obtained by reading the servo pattern 32 by the servo elements 36A and 36B included in the servo element pair 36 into a digital signal to the control device 18. Output.

  The control device 18 is connected to the actuator 60. The actuator 60 is attached to the read head 16 and applies power to the read head 16 under the control of the control device 18 to change the read head 16 in the tape width direction. The actuator 60 includes, for example, a voice coil motor, and the power applied to the read head 16 is obtained by converting electric energy based on the current flowing through the coil into kinetic energy using the energy of the magnet as a medium. It is power.

  Here, an example in which a voice coil motor is mounted on the actuator 60 is described, but the technology of the present disclosure is not limited to this, and for example, a piezoelectric element may be employed instead of the voice coil motor. Is possible. It is also possible to use a voice coil motor and a piezoelectric element in combination.

  The amount of positional deviation between the magnetic tape MT and the reading element unit 38 is determined according to a servo signal that is a result obtained by reading the servo pattern 32 by the servo element pair 36. The control device 18 controls the actuator 60 to apply power to the read head 16 according to the amount of positional deviation between the magnetic tape MT and the read element unit 38, thereby changing the read head 16 in the tape width direction. The position of the read head 16 is adjusted to a normal position. Here, the normal position refers to the position of the read head 16 when the magnetic tape reader 10 is in a default state, for example, as shown in FIG.

  Note that, here, the amount of positional deviation between the magnetic tape MT and the reading element unit 38 is illustrated, but the technology of the present disclosure is not limited to this. For example, a deviation amount between the servo element 36A and a predetermined reference position of the magnetic tape MT may be employed, or a deviation amount between the end face of the read head 16 and the center position of a specific track included in the magnetic tape MT. May be adopted. Thus, the amount of deviation may be any amount equivalent to the amount of deviation between the center of the reading target track 30A in the tape width direction and the center of the reading head 16 in the tape width direction. In the following, for the sake of convenience of explanation, the amount of displacement of the position between the magnetic tape MT and the reading element unit 38 is simply referred to as “deviation amount”.

  For example, as shown in FIG. 8, the deviation amount is calculated based on the ratio of the distance A to the distance B. The distance A indicates a distance calculated from a result obtained by reading the adjacent first oblique line 32A and second oblique line 32B by the servo element 36A. The distance B indicates a distance calculated from a result obtained by reading two adjacent first oblique lines 32A by the servo element 36A.

  The extraction unit 62 includes a control device 18 and a two-dimensional FIR (Finite Impulse Response) filter 71. The two-dimensional FIR filter 71 includes an adder 44, a first equalizer 70, and a second equalizer 72.

  The first equalizer 70 is connected to the first reading element 40 via the A / D converter 64. The first equalizer 70 is connected to each of the control device 18 and the adder 44. The data read from the specific track area 31 by the first reading element 40 is an analog signal, and the A / D converter 64 converts the data read from the specific track area 31 by the first reading element 40 into a digital signal. The first read signal obtained in this way is output to the first equalizer 70.

  The second equalizer 72 is connected to the second reading element 42 via the A / D converter 66. The second equalizer 72 is connected to each of the control device 18 and the adder 44. The data read from the specific track area 31 by the second reading element 42 is an analog signal, and the A / D converter 66 converts the data read from the specific track area 31 by the second reading element 42 into a digital signal. The second read signal obtained in this way is output to the second equalizer 72. The first reading signal and the second reading signal are examples of “read results for each reading element” according to the technique of the present disclosure.

  The first equalizer 70 performs waveform equalization processing on the input first read signal. That is, the first equalizer 70 performs a convolution operation on the tap coefficient with respect to the input first read signal, and outputs a first operation-processed signal that is a signal after the operation processing.

  The second equalizer 72 performs waveform equalization processing on the input second read signal. That is, the second equalizer 72 performs a convolution operation on the tap coefficient with respect to the input second read signal, and outputs a second operation-processed signal that is a signal after the operation processing.

  Each of the first equalizer 70 and the second equalizer 72 outputs the first arithmetic processed signal and the second arithmetic processed signal to the adder 44. The adder 44 combines the first arithmetic processed signal input from the first equalizer 70 and the second arithmetic processed signal input from the second equalizer 72, The synthesized data obtained by the synthesis is output to the decoding unit 69.

  Each of the first equalizer 70 and the second equalizer 72 is a one-dimensional FIR filter.

  In the embodiment of the present disclosure, the FIR filter itself is a series of real values including positive and negative, the number of rows in the series is referred to as a tap number, and the numerical value itself is referred to as a tap coefficient. Further, in the embodiment of the present disclosure, waveform equalization refers to a process of performing a convolution operation (product-sum operation) on the read signal with the above series of real values, that is, tap coefficients. The “read signal” referred to here is a generic name for the first read signal and the second read signal. In the embodiment of the present disclosure, the equalizer refers to a circuit that performs a process of performing a convolution operation on a tap coefficient with respect to a read signal or another input signal and outputting a signal after the arithmetic processing. In the embodiment of the present disclosure, an adder refers to a circuit that simply adds two sequences. The weights of the two sequences are reflected in the numerical values of the FIR filters used in the first equalizer 70 and the second equalizer 72, that is, tap coefficients.

  The control device 18 sets a tap coefficient corresponding to the shift amount for each of the FIR filters of the first equalizer 70 and the second equalizer 72, whereby the first equalizer 70 and the second equalizer. Each of the equalizers 72 is caused to execute waveform equalization processing corresponding to the amount of deviation.

  The control device 18 includes a correspondence table 18A. In the correspondence table 18A, the tap coefficient and the shift amount are associated with each of the first equalizer 70 and the second equalizer 72. The combination of the tap coefficient and the shift amount is, for example, a combination of the tap coefficient and the shift amount that provides the best combined data by the adder 44 based on the result of performing at least one of the test and simulation by an actual machine. As a combination obtained in advance. The “best synthesized data” here refers to data corresponding to the track data to be read.

  Here, “read target track data” refers to “data derived from the read target track 30A” according to the technique of the present disclosure. In other words, “data derived from the read target track 30A” refers to data corresponding to the data written in the read target track 30A. As an example of data corresponding to the data written in the read target track 30A, data read from the read target track 30A and not including noise components from adjacent tracks can be cited.

  Here, the correspondence table 18A is illustrated, but the technology of the present disclosure is not limited to this, and an arithmetic expression may be employed instead of the correspondence table 18A. The “arithmetic expression” here refers to, for example, an arithmetic expression in which an independent variable is a shift amount and a dependent variable is a tap coefficient.

  In the embodiment of the present disclosure, an example in which the tap coefficient is derived from the correspondence table 18A in which the combination of the tap coefficient and the shift amount is defined is given, but the technology of the present disclosure is not limited to this. For example, the tap coefficient may be derived from a correspondence table or an arithmetic expression in which a combination of the tap coefficient and the ratio is defined. The “ratio” here refers to the ratio of the overlapping area of the reading target track 30A and the overlapping area of the adjacent track for each of the first reading element 40 and the second reading element 42. The ratio is specified by calculating from the deviation amount by the control device 18, and the tap coefficient is determined according to the specified ratio.

  The decoding unit 69 decodes the combined data input from the adder 44 and outputs a decoded signal obtained by decoding to the computer 73. The computer 73 performs various processes on the decoded signal input from the decoding unit 69.

  Next, a magnetic tape reading process executed by the extraction unit 62 will be described with reference to FIG. 9 as an operation of a portion related to the technique of the present disclosure of the magnetic tape reader 10.

  In the following, for convenience of explanation, it is assumed that a servo signal is input to the control device 18 when the sampling time comes. Here, the sampling means not only the sampling of the servo signal but also the sampling of the read signal. That is, in the embodiment of the present disclosure, since the track area 30 is formed in parallel with the servo pattern 32 along the traveling direction, the reading operation by the reading element unit 38 is synchronized with the reading operation by the servo element pair 36. Done.

  In the process shown in FIG. 9, first, in step 100, the control device 18 determines whether or not the sampling time has come. If it is determined in step 100 that the sampling time has come, the determination is affirmed, and the magnetic tape reading process proceeds to step 102. In step 100, if the sampling time has not arrived, the determination is negative and the determination in step 100 is performed again.

  In step 102, the first equalizer 70 acquires the first read signal, the second equalizer 72 acquires the second read signal, and then the magnetic tape reading process proceeds to step 104.

  In step 104, the control device 18 acquires a servo signal, calculates a deviation amount from the acquired servo signal, and then the magnetic tape reading process proceeds to step 106.

  In step 106, the control device 18 sets a tap coefficient corresponding to the shift amount calculated in the process of step 104 for each of the first to third taps of the first equalizer 70 and the second equalizer 72. Derived from 18A. That is, by executing the processing of step 106, an optimal combination as a combination of a one-dimensional FIR filter that is an example of the first equalizer 70 and a one-dimensional filter that is an example of the second equalizer 72 is obtained. Determined. The “optimal combination” mentioned here refers to, for example, a combination in which composite data output by executing the process of step 112 described later is data corresponding to the track data to be read.

  In the next step 108, the control device 18 sets the tap coefficient derived in the process of step 106 for each of the first equalizer 70 and the second equalizer 72, and the magnetic tape reading process thereafter. 110.

  In step 110, the first equalizer 70 performs a waveform equalization process on the first read signal acquired in the process of step 102, thereby generating a first arithmetic processed signal. The first equalizer 70 outputs the generated first arithmetic processed signal to the adder 44. The second equalizer 72 performs a waveform equalization process on the second read signal acquired in the process of step 102 to generate a second arithmetic processed signal. The second equalizer 72 outputs the generated second arithmetic processed signal to the adder 44.

  In the next step 112, the adder 44, as shown in FIG. 10 as an example, the first processed signal input from the first equalizer 70 and the second signal input from the second equalizer 72. The signal is synthesized by adding the two processed signals. Then, the adder 44 outputs the combined data obtained by combining to the decoding unit 69.

  When the reading element unit 38 is arranged on the specific track area 31 as in the example shown in FIG. 3, the processing of this step 112 is executed, so that as synthesized data, from the first noise mixing source track 30B. The data corresponding to the read target track data from which the noise component is removed is output. That is, by executing the processing of step 102 to step 112, the extraction unit 62 extracts only data derived from the reading target track 30A.

  When the tape width direction of the magnetic tape MT is expanded or contracted, or when vibration is applied to at least one of the magnetic tape MT and the read head 16, the reading element unit 38 is moved from the position shown in FIG. 3 as an example. It may be displaced to the position shown in FIG. In the example shown in FIG. 11, the first reading element 40 and the second reading element 42 are arranged at positions that straddle both the reading target track 30 </ b> A and the second noise-mixing source track 30 </ b> C. In this case, by executing the processing from step 102 to step 112, data corresponding to the read target track data from which the noise component from the second noise-mixing source track 30C has been removed is output to the decoding unit 69 as synthesized data. Is done.

  In the next step 114, the control device 18 determines whether or not a condition for ending the magnetic tape reading process (hereinafter referred to as “end condition”) is satisfied. The end condition refers to, for example, a condition that all of the magnetic tape MT has been taken up by the take-up reel 22, and a condition that an instruction to forcibly end the magnetic tape reading process is given from the outside.

  If the end condition is not satisfied in step 114, the determination is negative and the magnetic tape reading process proceeds to step 100. If the end condition is satisfied in step 114, the determination is affirmed and the magnetic tape reading process ends.

  As described above, in the magnetic tape reader 10, the data is read from the specific track area 31 by the first reading element 40 and the second reading element 42 that are arranged close to each other. Then, the extraction unit 62 applies a waveform equalization process corresponding to the shift amount to each of the first reading element 40 and the second reading element 42, so that the first reading signal and the second reading signal are used. Data derived from the reading target track 30A is extracted. Accordingly, the magnetic tape reader 10 has a lower reliability of data read from the read target track 30A by the linear scan method than when the data is read from the read target track 30A by only a single reading element by the linear scan method. Can be suppressed.

  In the magnetic tape reader 10, a part of the first reading element 40 and the second reading element 42 overlap each other in the traveling direction. Therefore, the magnetic tape reader 10 can increase the reliability of data read from the read target track 30A by the linear scan method, as compared with the case where the plurality of reading elements are overlapped with each other in the traveling direction.

  In the magnetic tape reader 10, the specific track area 31 includes the reading target track 30A, the first noise mixing source track 30B, and the second noise mixing source track 30C, and the first reading element 40 and the second reading track 30C. Each of the elements 42 straddles both the read target track 30A and the adjacent track when the positional relationship with the magnetic tape MT changes. Therefore, the magnetic tape reader 10 enters the adjacent track from the read target track 30A in the tape width direction as compared with the case where the data is read from the read target track 30A by only a single reading element by the linear scan method. A noise component generated in one of the reading element 40 and the second reading element 42 is reduced by using a reading result by the other reading element entering the adjacent track from the reading target track 30A in the tape width direction. be able to.

  In the magnetic tape reader 10, the tap coefficient used in the waveform equalization process is determined according to the shift amount. Therefore, the magnetic tape reader 10 can detect a noise component generated by entering the read target track 30A from the adjacent track in the tape width direction as compared with a case where the tap coefficient is determined according to a parameter not related to the shift amount. This can be immediately reduced following the change in the positional relationship between the magnetic tape MT and the reading element unit 38.

  Further, in the magnetic tape reader 10, the ratio between the overlapping area of the reading target track 30A and the overlapping area of the adjacent track is specified from the deviation amount for each of the first reading element 40 and the second reading element 42, and specified. The tap coefficient is determined according to the ratio. Accordingly, in the magnetic tape reader 10, the tap coefficient is determined according to a parameter that is not related to the ratio of the overlapping area of the reading target track 30A and the overlapping area of the adjacent track for each of the plurality of reading elements. Compared to the case, even if the positional relationship between the magnetic tape MT and the reading element unit 38 changes, the noise component can be accurately reduced.

  In the magnetic tape reader 10, the deviation amount is determined according to the result obtained by reading the servo pattern 32 by the servo element pair 36. Therefore, the magnetic tape reader 10 can easily determine the amount of deviation compared to the case where the servo pattern 32 is not applied to the magnetic tape MT.

  In the magnetic tape reader 10, the reading operation by the reading element unit 38 is performed in synchronization with the reading operation by the servo element pair 36. Therefore, the magnetic tape reading device 10 enters the reading target track from the adjacent track in the width direction of the magnetic tape as compared with the magnetic disk and the helical scan type magnetic tape that cannot read the servo pattern and the data synchronously. The generated noise component can be immediately reduced.

  Further, in the magnetic tape reader 10, the extraction unit 62 has a two-dimensional FIR filter 71. Then, the two-dimensional FIR filter 71 synthesizes the results obtained by performing waveform equalization processing on each of the first read signal and the second read signal, thereby obtaining the first read signal and the first read signal. Data derived from the read target track 30A is extracted from the two read signals. Therefore, the magnetic tape reader 10 can quickly extract data derived from the read target track 30A from the first read signal and the second read signal, compared to the case where only the one-dimensional FIR filter is used. Further, the magnetic tape reader 10 can realize simple mounting with a smaller amount of calculation compared to the case of performing matrix calculation.

  In the magnetic tape reader 10, the first reading element 40 and the second reading element 42 are employed as a pair of reading elements according to the technique of the present disclosure. Therefore, the magnetic tape reader 10 can contribute to the size reduction of the reading element unit 38 as compared with the case where three reading elements are used. Since the reading element unit 38 is downsized, the reading unit 26 and the reading head 16 can also be downsized. Further, the magnetic tape reader 10 can also suppress the occurrence of a situation where the adjacent reading element units 38 are in contact with each other.

  Further, in the magnetic tape reader 10, the data is read by the linear scanning method from the corresponding reading target track 30 </ b> A included in each of the plurality of specific track areas 31 by each of the plurality of reading element units 38. Therefore, the magnetic tape reading apparatus 10 completes the reading of data from the plurality of reading target tracks 30A more quickly than when data is read from each of the plurality of reading target tracks 30A by only the single reading element unit 38. can do.

  In the above-described embodiment, when the magnetic tape reader 10 is in a default state, each of the first reading element 40 and the second reading element 42 corresponds to both the reading target track 30A and the first noise mixing source track 30B. However, the technology of the present disclosure is not limited to this. In the example shown in FIG. 12, a reading element unit 138 is employed instead of the reading element unit 38 described in the above embodiment. The reading element unit 138 includes a first reading element 140 and a second reading element 142. In the default state of the magnetic tape reader 10, the center of the first reading element 140 in the tape width direction coincides with the center CL of the read target track 30A in the tape width direction. Further, in the default state of the magnetic tape reader 10, the first reading element 140 and the second reading element 142 do not protrude into the first noise mixing source track 30B and the second noise mixing source track 30C. It is within the track 30A to be read. Further, in the default state of the magnetic tape reading device 10, each of the first reading element 140 and the second reading element 142 is in the running state, similarly to the first reading element 40 and the second reading element 42 described in the above embodiment. It is provided so that a part of each other overlaps in the direction.

  As an example, as shown in FIG. 12, even when the first reading element 140 and the second reading element 142 face the reading target track 30A without protruding from the reading target track 30A, The positional relationship with the magnetic tape MT may change. In other words, the reading element unit 138 may straddle the reading target track 30A and the first noise mixing source track 30B, and the reading element unit 138 may straddle the reading target track 30A and the second noise mixing source track 30C. . Even in these cases, the reading of the noise component from the first noise mixing source track 30B or the second noise mixing source track 30C is removed by executing the processing of step 102 to step 112 described above. Data corresponding to the target track data can be obtained.

  In addition, since the first reading element 140 and the second reading element 142 are arranged at positions where a part of each other overlaps in the traveling direction, from the portion of the reading target track 30A that cannot be read by the first reading element 140. The second reading element 142 can read data. As a result, it is possible to improve the reliability of the read target track data as compared with the case where the single first read element 140 reads data from the read target track 30A.

  As an example, as shown in FIG. 11, when the magnetic tape reader 10 is in a default state, each of the first reading element 40 and the second reading element 42 includes a reading target track 30A and a second noise-mixing source track 30C. They may be arranged at positions that straddle both.

  Moreover, in the said embodiment, although the reading element unit 38 containing the 1st reading element 40 and the 2nd reading element 42 was illustrated, the technique of this indication is not limited to this. In the example shown in FIG. 13, a reading element unit 238 is employed instead of the reading element unit 38. The reading element unit 238 is different from the reading element unit 38 in that it has a third reading element 244. When the magnetic tape reader 10 is in a default state, the third reading element 244 is disposed between the first reading element 40 and a part of the third reading element 244 in the traveling direction. In the default state of the magnetic tape reader 10, the third reading element 244 is disposed at a position straddling the reading target track 30A and the second noise-mixing source track 30C.

  In this case, the first equalizer 70 is assigned to the first reading element 40, and the second equalizer 72 is assigned to the second reading element 42. A 3 equalizer (not shown) is assigned. The third equalizer also has the same function as the first equalizer and the second equalizer described in the above embodiment, and the third read signal obtained by being read by the third reading element 244. Is subjected to waveform equalization processing. Then, the third equalizer performs a convolution operation on the tap coefficient with respect to the third read signal, and outputs a third operation-processed signal that is a signal after the operation processing. The adder 44 has a first operation processed signal corresponding to the first read signal, a second operation processed signal corresponding to the second read signal, and a third operation processed corresponding to the third read signal. The signals are combined by adding the signals, and the combined data obtained by combining is output to the decoding unit 69.

  In the example shown in FIG. 13, the magnetic tape reader 10 is in a default state, and the third reading element 244 is arranged at a position straddling the reading target track 30 </ b> A and the second noise mixing source track 30 </ b> C. However, the technology of the present disclosure is not limited to this. The third reading element 244 may be arranged at a position facing the reading target track 30A without protruding from the reading target track 30A in the default state of the magnetic tape reading device 10.

  Moreover, in the said embodiment, although the reading element unit 38 was illustrated, the technique of this indication is not limited to this. For example, instead of the reading element unit 38, a reading element pair 50 shown in FIG. 4 may be employed. In this case, the first reading element 50A and the second reading element 50B are arranged at positions close to each other in the tape width direction. Further, the first reading element 50A and the second reading element 50B are not in contact with each other, and the SNR is higher than the SNR of the single reading element data in the entire range of the track offset as shown in FIG. 6 as an example. So that they are arranged side by side in the tape width direction.

  In the example shown in FIG. 4, for example, the first reading element 50A is housed in the second track 49B in a plan view, and the second reading element 50B is housed in the first track 49A in a plan view.

  In the above embodiment, the servo element pair 36 has been exemplified. However, the technology of the present disclosure is not limited to this, and, for example, one of the servo elements 36A and 36B is adopted instead of the servo element pair 36. May be.

  Further, in the above-described embodiment, a description has been given of an example in which a plurality of specific track areas 31 are arranged at a constant interval in the tape width direction in the track area 30, but the technology of the present disclosure is not limited to this. . For example, in two adjacent specific track areas 31 among a plurality of specific track areas 31, the tape width is such that one specific track area 31 and the other specific track area 31 overlap by one track in the tape width direction. You may make it arrange in a direction. That is, in this case, one adjacent track (for example, the first noise-mixing source track 30B) included in one specific track region 31 becomes the read target track 30A in the other specific track region 31. Further, the read target track 30A included in one specific track area 31 becomes an adjacent track area (for example, the second noise-mixing source track 30C) in the other specific track area 31.

  Further, the magnetic tape reading process described in the above embodiment is merely an example. Therefore, it goes without saying that unnecessary steps may be deleted, new steps may be added, and the processing order may be changed within a range not departing from the spirit.

  All documents, patent applications and technical standards mentioned in this specification are to the same extent as if each individual document, patent application and technical standard were specifically and individually stated to be incorporated by reference. Incorporated by reference in the book.

  Regarding the above embodiment, the following additional notes are disclosed.

(Appendix 1)
A reading element unit having a plurality of reading elements is arranged in a state where the plurality of reading elements are brought close to each other,
A plurality of reading elements respectively read data from a specific track area including a reading target track among the track areas included in the magnetic tape by a linear scan method,
The extraction unit applies a waveform equalization process according to the amount of positional deviation between the magnetic tape and the reading element unit to each reading result for each reading element, and is derived from the reading target track from the reading result. A method for reading magnetic tape comprising extracting data.

(Appendix 2)
A reading element unit having a plurality of reading elements each for reading data from a specific track area including a reading target track among the track areas included in the magnetic tape by a linear scanning method is arranged in a state where the plurality of reading elements are brought close to each other. ,
The extraction unit applies a waveform equalization process according to the amount of positional deviation between the magnetic tape and the reading element unit to each reading result for each reading element, and is derived from the reading target track from the reading result. A method for reading magnetic tape comprising extracting data.

(Appendix 3)
The magnetic tape reading method according to Supplementary Note 1 or Supplementary Note 2, wherein a part of each of the plurality of reading elements overlaps each other in the traveling direction of the magnetic tape.

(Appendix 4)
The specific track area is an area including a read target track and an adjacent track adjacent to the read target track,
The magnetic tape reading method according to appendix 3, wherein each of the plurality of reading elements straddles both the reading target track and the adjacent track when the positional relationship with the magnetic tape changes.

(Appendix 5)
Data is read from each of a plurality of specific track areas each including a target track of track areas included in the magnetic tape by a linear scan method, and a plurality of reading elements each having a plurality of reading elements arranged in proximity to each other An element unit;
For each of the plurality of reading element units, each of the reading results for each reading element is subjected to waveform equalization processing according to the amount of positional deviation between the magnetic tape and the reading element unit, thereby reading from the reading results. A magnetic tape reader including an extraction unit for extracting data derived from a target track.

(Appendix 6)
The magnetic tape reading device according to appendix 5, wherein in each of the plurality of reading element units, a part of each of the plurality of reading elements overlaps in the traveling direction of the magnetic tape.

(Appendix 7)
The specific track area is an area including a read target track and an adjacent track adjacent to the read target track,
In each of the plurality of reading element units, each of the plurality of reading elements extends over both the reading target track and the adjacent track when the positional relationship with the magnetic tape changes. Magnetic tape reader.

(Appendix 8)
The magnetic tape reading device according to appendix 5, wherein in each of the plurality of reading element units, the plurality of reading elements are arranged side by side in a state of being close to each other in the width direction of the magnetic tape.

(Appendix 9)
In each of the plurality of reading element units, the plurality of reading elements are included in the reading target track in the width direction of the magnetic tape, and the magnetic tape reading device according to any one of the appendix 5 to the appendix 8.

(Appendix 10)
10. The magnetic tape reader according to any one of appendix 5 to appendix 9, wherein the tap coefficient used in the waveform equalization process is determined according to a deviation amount.

(Appendix 11)
For each of the plurality of reading elements of each of the plurality of reading element units, the ratio between the overlapping area with the reading target track and the overlapping area with the adjacent track adjacent to the reading target track is specified and specified from the deviation amount. The magnetic tape reader according to appendix 10, wherein a tap coefficient is determined according to the ratio.

(Appendix 12)
12. The magnetic tape reading device according to any one of appendix 5 to appendix 11, wherein the deviation amount is determined according to a result obtained by a servo element reading a servo pattern previously applied to the magnetic tape.

(Appendix 13)
The magnetic tape reading device according to appendix 12, wherein the reading operation by each of the plurality of reading element units is performed in synchronization with the reading operation by the servo element.

(Appendix 14)
The extraction unit has a two-dimensional FIR filter,
The two-dimensional FIR filter synthesizes each result obtained by performing waveform equalization processing on each of the reading results for each reading element for each of the plurality of reading element units. 14. The magnetic tape reader according to any one of appendix 5 to appendix 13, wherein data derived from a read target track included in the specific track region corresponding to the position of the specific track region is extracted.

(Appendix 15)
The magnetic tape reader according to any one of appendix 5 to appendix 14, wherein the plurality of read elements are a pair of read elements.

DESCRIPTION OF SYMBOLS 10 Magnetic tape reader 12 Magnetic tape cartridge 14 Conveyor 16 Read head 18 Controller 18A Corresponding table 20 Sending motor 22 Take-up reel 24 Take-up motor 26 Reading part 28 Holder 30, 49 Track area 30A Reading object track 30B 1st Noise mixed source track 30C Second noise mixed source track 31 Specific track area 32 Servo pattern 32A First oblique line 32B Second oblique line 36 Servo element pairs 36A, 36B, 208 Servo elements 38, 138, 238 Read element units 40, 50A, 140 First reading element 42, 50B, 142 Second reading element 44 Adder 49A First track 49B Second track 49C Third track 50 Reading element pair 60 Actuator 62 Extraction units 64, 66, 68 A / D converter 69 Decoding Part 70 First equalization Device 71 Two-dimensional FIR filter 72 Second equalizer 73 Computer 200 Read head 202 Read element 204, MT magnetic tape 206 Track 244 Third read element CL Center CR Cartridge reel GR Guide roller MT Magnetic tape

Claims (13)

A reading element unit having a plurality of reading elements arranged in close proximity, each reading data from a specific track area including a reading target track among the track areas included in the magnetic tape by a linear scan method;
For each of the reading results for each of the reading elements, a waveform equalization process corresponding to the amount of positional deviation between the magnetic tape and the reading element unit is performed, so that the reading result is derived from the reading target track. An extraction unit for extracting data to be processed;
A magnetic tape reader.   The magnetic tape reading device according to claim 1, wherein a part of each of the plurality of reading elements overlaps in a traveling direction of the magnetic tape. The specific track area is an area including the read target track and an adjacent track adjacent to the read target track,
3. The magnetic tape reading device according to claim 2, wherein each of the plurality of reading elements straddles both the reading target track and the adjacent track when the positional relationship with the magnetic tape changes. .   The magnetic tape reader according to claim 1, wherein the plurality of reading elements are arranged side by side in a state of being close to each other in the width direction of the magnetic tape.   5. The magnetic tape reader according to claim 1, wherein the plurality of reading elements are accommodated in the reading target track in a width direction of the magnetic tape. 6.   The magnetic tape reader according to claim 1, wherein a tap coefficient used in the waveform equalization process is determined according to the shift amount.   For each of the plurality of reading elements, a ratio between an overlapping area with the reading target track and an overlapping area with an adjacent track adjacent to the reading target track is specified from the shift amount, and the specified ratio is The magnetic tape reader according to claim 6, wherein the tap coefficient is determined accordingly.   The magnetic tape reader according to any one of claims 1 to 7, wherein the deviation amount is determined according to a result obtained by a servo element reading a servo pattern previously applied to the magnetic tape.   The magnetic tape reading device according to claim 8, wherein the reading operation by the reading element unit is performed in synchronization with the reading operation by the servo element. The extraction unit has a two-dimensional FIR filter,
The two-dimensional FIR filter is derived from the read result from the read target track by synthesizing the results obtained by performing the waveform equalization processing on each of the read results for each reading element. The magnetic tape reader according to any one of claims 1 to 9, wherein data is extracted.   The magnetic tape reader according to claim 1, wherein the plurality of reading elements are a pair of reading elements. Data is read from each of a plurality of specific track areas each including a target track of track areas included in the magnetic tape by a linear scan method, and a plurality of reading elements each having a plurality of reading elements arranged in proximity to each other An element unit;
For each of the plurality of reading element units, by applying a waveform equalization process according to the amount of positional deviation between the magnetic tape and the reading element unit for each reading result for each reading element, An extraction unit that extracts data derived from the reading target track from the reading result;
A magnetic tape reader. A reading element unit having a plurality of reading elements is disposed in a state where the plurality of reading elements are close to each other,
The plurality of reading elements respectively read data from a specific track area including a reading target track among the track areas included in the magnetic tape by a linear scan method,
The extraction unit performs waveform equalization processing according to the amount of positional deviation between the magnetic tape and the reading element unit for each of the reading results for each of the reading elements. A magnetic tape reading method including extracting data derived from a target track.