CN1244109C - Index servo position search of offset servotrack edge - Google Patents
Index servo position search of offset servotrack edge Download PDFInfo
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- CN1244109C CN1244109C CNB001292234A CN00129223A CN1244109C CN 1244109 C CN1244109 C CN 1244109C CN B001292234 A CNB001292234 A CN B001292234A CN 00129223 A CN00129223 A CN 00129223A CN 1244109 C CN1244109 C CN 1244109C
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/54—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head into or out of its operative position or across tracks
- G11B5/55—Track change, selection or acquisition by displacement of the head
- G11B5/5504—Track change, selection or acquisition by displacement of the head across tape tracks
- G11B5/5508—Control circuits therefor
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B5/584—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following on tapes
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B2220/00—Record carriers by type
- G11B2220/90—Tape-like record carriers
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- Adjustment Of The Magnetic Head Position Track Following On Tapes (AREA)
- Moving Of The Head To Find And Align With The Track (AREA)
Abstract
A servo position detector and a method for detecting and following an index position displaced at an offset with respect to an edge of a servo track, an edge comprising an interface between two dissimilar recorded servo signals. The servo track has two edges on opposite lateral sides of a middle recorded servo signal, the edges separated by a predetermined distance. A servo read element has an active sensing region which is no more than and is substantially the entire predetermined distance separating the edges, an independent position sensor senses the coarse position of the servo read element, logic compares the two sensed servo signals to determine the ratio therebetween, and determines an error between the compared ratio and a predetermined ratio. A servo positioner moves the servo read element to reduce the servo position error.
Description
The application is the U. S. application No.09-365 that is entitled as " DECODING DIGITALLY SAMPLED SERVOTRACKS ", 898 part continuation application, this application in Augusts 13 in 1999 order be submitted to United States Patent (USP) trademark office.
The general U.S. Patent No. of transferring the possession of 5,448,430 is in conjunction with introducing, being used to showing that it is used for the servo track that magnetic track is followed servo-drive system, and the general U.S. Patent No. of transferring the possession of 5,844,814 in conjunction with introducing, to be used for showing the independent position sensor of its head positioning system.
Technical field
The present invention relates to the detection of the servo track locating information of record in advance, more particularly, relate to the detection of the servo track locating information of the servo track that has two edges at least and follow, each edge is included in two interphases between the different recording servosignal, read by a servo read element, to allow location servo read element and corresponding data head.
Background technology
In data storage industry, development of technology comprises the increase of the data storage capacity of given data storage medium.Increasing for example a kind of measure of the data storage capacity of tape cassete or bin of data storage medium, be the track density that increases data storage medium, and press corresponded manner, is the width that reduces each track.
In typical tape, data are recorded in a plurality of parallel data-tracks longitudinally.Data head can be a plurality of data heads that have less read/write element than track.Data-track is divided into the group of several typically interlacing, and the horizontal index of data head relative orbit, with the data-track of each group of access.For with data-track record data head suitably, provide the in advance servo track of record parallel with data-track.The servo read head that relative read/write element is positioned at the index position place is read servo track.Servo track provides located lateral information, and this information can be decoded when being read by servo read head, and whether relative servo track is correctly located to indicate servo read head.Therefore, servo head servo track relatively moves laterally to desired location, so that the data track group of wishing suitably writes down read/write element relatively.So, when servo head can vertically move, follow servo track, so that read/write element keeps the record with data-track between medium is relative with head.
As an example, Ji Lu servo track locating information comprises that adjacent servo track has different servo figures in advance, one of servo figure comprises the constant amplitude signal of single first frequency, and another servo figure between the constant amplitude pulse signal of single second frequency and null spacing wave alternately.Interphase between the adjacent servosignal is called " edge ".The composite signal of being read by servo head is to comprise the peak signal that the first frequency signal combines with the second frequency pulse signal and comprise the minimum signal that the first frequency signal combines with spacing wave.If servo head correctly is positioned at the joint of adjacent servo track, in conjunction with the amplitude of first and second frequency signals are twices of amplitude of first and spacing wave of combination, and decoding easily.The common United States Patent (USP) N0.5 that transfers the possession of, 448,430 have illustrated the servo track figure of above-mentioned discussion, and have narrated and used peak detection to determine that the track of minimum and maximum signal follows servo positioning system.
Along with the increase of data capacity, wish that also the data storage medium with available data capacity level is had backward compatibility, so that avoid must be being recorded in all copying datas on the existing medium to new medium.
Summary of the invention
Therefore an object of the present invention is in the track density that increases data storage medium, utilize existing medium servo track, so that servo-drive system can be operating as in the past for existing medium, utilize the servo track locating information, and utilize identical servo track locating information in more accurate mode, with access track under higher orbit density.
The invention provides a kind of method that is used to survey the servo positioning of a relative servo track, described servo track has two edges at least, each described edge comprises an interphase between two different record servosignals, described edge is at the relative side of a described record servosignal in centre, described edge is a preset distance separately, described method comprises step: locate no more than two in the described different recording servosignal of sensing at one of described edge, described sensing step is sensing on a distance with one of the described quadrature at described edge, described distance is left the twice of one of the described displacement at described edge greater than the predetermined index position, and the described preset distance that separates described edge 80% and 100% between; More described two sensitive servo signals, with determine between them relatively than; And respond described comparison step, determine described sensitive servo signal described relatively than and one predetermined than between error, described predetermined ratio comprises one along feel relieved the relatively predetermined migration of edge ratio of predetermined direction, described predetermined one of described parallel than one of identification and described edge, and the predetermined index position of one of the described displacement at described relatively edge, the described servo positioning of the described relatively servo track predetermined index of described error detection position.
The invention provides a kind of method that is used to follow the servo index position relevant with servo track, described servo track has two edges at least, each described edge comprises an interphase between two different record servosignals, described edge is at the relative side of a described record servosignal in centre, described edge is a preset distance separately, described servo index position and described edge one of described parallel, and one of the described displacement at described relatively edge, described method comprises step: locate the described different recording servosignal of sensing at one of described edge no more than two, described sensing step is sensing on a distance with one of the described quadrature at described edge, described sensing step distance is left the twice of one of the described described displacement at described edge greater than described predetermined index position, and the described preset distance that separates described edge 80% and 100% between; More described two sensitive servo signals, with determine between them relatively than; Respond described comparison step, determine described relatively sensitive servo signal described relatively than and one predetermined than between error, described predetermined ratio comprises one along feel relieved the relatively predetermined migration of edge ratio of predetermined direction, to determine the servo position error of described relatively servo index position; And servo, thereby follow described servo index position along the location of direction operation that reduces described servo position error.
The invention provides a kind of method that is used to select and follows one of a plurality of predetermined index position of a servo track, input is responded, to discern a described predetermined index position, described servo track has two edges at least, each described edge comprises an interphase between two different record servosignals, described edge is parallel to each other, and on the relative side of a described record servosignal in centre, described edge is a preset distance separately, servosignal in the middle of each position of described a plurality of predetermined index position is described relatively, along first or second sense of displacement that leaves each described edge displacement respectively, described method comprises step: locate no more than two in the described different recording servosignal of sensing at one of described edge, described sensing step is sensing on a distance with one of the described quadrature at described edge, described sensing step distance is left 2 times of one of described described displacement at described edge greater than described predetermined index position, and the described preset distance that separates described edge 80% and 100% between; The current apparent position of the relative reference of the described sensing step of sensing independently; Respond described independent sensing step, the current location of indication in described a plurality of predetermined index position of described sensing step sensing; Respond described current index position indication step, and the predetermined index position of described input identification, at first point to the direction of the described input recognizing site in the described predetermined index position along the current index position of described indication, it is servo to operate a location, thereby selects the described recognizing site of described predetermined index position; Respond described sensing step, more described two sensitive servo signals, with determine between them relatively than; Respond described comparison step, determine described relatively sensitive servo signal described relatively than and one predetermined than between error, described predetermined ratio comprises a described predetermined direction along the described chosen position of described predetermined index position, the predetermined migration of relative centering edge ratio, thereby the servo position error of the predetermined index position of definite described relatively selection; And servo, thereby follow the predetermined index position of described selection along reducing the described location of direction sequential operation of described servo position error.
The invention provides a kind of method that is used to select and follows one of a plurality of predetermined index position of a servo track, input is responded, to discern a described predetermined index position, described servo track has two edges at least, each described edge comprises an interphase between two different record servosignals, described edge is parallel to each other, and on the relative side of a described record servosignal in centre, described edge is a preset distance separately, servosignal in the middle of described a plurality of predetermined index position is described relatively, along first or second sense of displacement that leaves each described edge displacement respectively, described method comprises step: locate no more than two in the described different recording servosignal of sensing at one of described edge, described sensing step is sensing on a distance with one of the described quadrature at described edge, described sensing step distance is left 2 times of one of described described displacement at described edge greater than described predetermined index position, and the described preset distance that separates described edge 80% and 100% between; The current apparent position of the relative reference of the described sensing step of sensing independently, described current apparent position indication is detected described in the middle of servosignal work as leading edge; The servosignal of more described two sensings, with determine between them relatively than; By described relatively bigger than definite which described sensitive servo signal, the sense of displacement when leading edge of the described relatively indication of the described sensing step of described definite indication; Respond described independent sensing step, and described sense of displacement determining step, use indication of described edge and described analogy to determining, by the described sense of displacement when leading edge of described relatively indication, the current location in the described predetermined index position of indication sensing in described sensing step; Respond described current index position indication step, and the predetermined index position of described input identification, at first point to the direction of the described input recognizing site in the described predetermined index position along described current index position, it is servo to operate a location, thereby selects the described input recognizing site in the described predetermined index position; Respond described comparison step, determine described relatively sensitive servo signal described relatively than and one predetermined than between error, described predetermined ratio comprises a described predetermined direction along the described chosen position of described predetermined index position, the predetermined migration of relative centering edge ratio, thereby the servo position error of the predetermined index position of definite described relatively selection; And servo, thereby follow the predetermined index position of described selection along reducing the described location of direction sequential operation of described servo position error.
The present invention also provides a kind of servo position detector and a kind of method, to survey the servo positioning of relative indexing position, skew of the relative servo track displacement of index position.Servo track has two edges at least, and each edge is included in two interphases between the different recording servosignal.The edge is at the relative side of the servosignal of an intermediate record, and the edge separates preset distance.
Sensor comprises a servo read element, and it has an effective sensing unit, is not more than and is the whole preset distance at edge separately haply.Therefore, thus servo read element is located no more than two in the sensing different recording servosignal at one of edge.With the logical circuit of servo read element coupling two sensitive servo signals relatively, determining the ratio between them, and definite sensitive servo signal relatively than and predetermined than between error.Predetermined ratio is included in the predetermined migration of the edge placed in the middle ratio of the relative amplitude of predetermined direction, and the identification index position.Index position is parallel with the edge haply, and departs from the edge.
Logical circuit provides one and definite error output signal related, the servo position error of this output signal identification relative indexing position.
In yet another embodiment of the present invention, provide servo track follower and method, to survey and to follow the servo index position relevant with servo track.Servo positioning device and logical circuit coupling, and along the direction shift servo reading component that reduces servo position error.
In another embodiment of the present invention, the displacement of one of index position opposite edges is to separate 1/4 of the preset distance at edge haply, always has four index positions, and each side is one at the edge.Another embodiment uses as edge of the prior art, and has 1/3 the index position that displacement is the preset distance at separately edge haply in addition, always has six index positions.The effective sensing unit of servo read element distance be included in edge separately preset distance roughly 80% and roughly between 100%.
In yet another embodiment of the present invention, the servo positioning for the servo track of surveying a plurality of relatively parallel spaced apart separates a plurality of servo read element, with two unlike signals of each corresponding edge sensing at servo track.Logical circuit is average to two unlike signals of inductive sensing separately a plurality of reading components in addition, and determine average different servo signal relatively than and predetermined than between error.
In yet another embodiment of the present invention, an independent position sensor is provided in addition, with the apparent position of the relative reference of sensitive servo reading component, which edge of apparent position indication servo track is aimed at servo read element, and is surveyed by servo read element.Logical circuit uses apparent position in addition, with identification predetermined index position, and selects predetermined ratio.
An input end receiving inputted signal, and logical circuit and the coupling of this input end.The input signal that logical circuit response receives to determine the index position of identification, is selected the predetermined ratio of the predetermined index position of edge and expression input indication, and predetermined ratio is included in feel relieved the relatively predetermined migration of edge ratio of predetermined direction.Servo read element with effective sensing unit is extended with one of edge quadrature haply, to locate no more than two in the sensing different recording servosignal at one of edge.The current apparent position of the relative reference of an independent position sensor sensitive servo reading component, the indication of current apparent position are aimed at servo head and by the current location error in the predetermined index position of the servo track of servo head detection.Logical circuit and this independent position sensor are coupled, and are coupled with servo read element.Logical circuit responds current apparent position, with the current index position of indication by the servo read element detection.Logical circuit responds the index position of current index position and input identification, and it is servo at first to point to the direction operation location of importing the identification index position with current index position, thereby selects the input in the predetermined index position to discern index position.Logical circuit compares two sensitive servo signals then, to determine the ratio between them, and the error between the ratio of definite relatively transducing signal and the predetermined ratio of the selection of the selection index position in the predetermined index position, thereby the servo position of definite relative this index position.Logical circuit is to the servo site error output that provides is provided, and is servo to locate along the direction operation that reduces described servo position error, thereby follows the predetermined index position of selection.
Description of drawings
In order to understand the present invention more completely, should be with reference to following together with being described in detail that accompanying drawing is done.
Fig. 1 is to use the calcspar of magnetic tape system of the present invention;
Fig. 2 is the illustrative of the magnetic tape format of two servo index positions in conjunction with servo track;
Fig. 3 is the illustrative of magnetic tape format used according to the invention, Fig. 1 servo track is provided four servo index positions;
Fig. 4 is the calcspar of explanation servo track positioning system, with the asynchronous digital sampling decoding of writing down the servo track locating information in advance to Fig. 1 tape, and to read/write element according to the present invention location;
Fig. 5 is a plurality of servo track demoders of Fig. 4 and the calcspar of the servo track demoder being supplied with the interface of numerical value able to programme;
Fig. 6 A and Fig. 6 B are the explanations for the example modelled servosignal of the diverse location of servo read head, and the explanation of the example of the digital packets winding thread of the signal of analog servomechanism separately that is produced by the servo track demoder of Fig. 4 and Fig. 5;
Fig. 7 to Figure 12 is the calcspar of the embodiment of servo track demoder of the present invention;
Figure 13 to Figure 18 is a process flow diagram of describing the embodiment of method of the present invention;
Figure 19 is the magnetic tape format of two servo position of two edges servo track and the explanation of prior art servo read element;
Figure 20 is to use the detailed illustrative according to the tape-servo track of servo read element of the present invention, so that four servo index positions of Fig. 3 to be provided;
Figure 21 has 3 separately illustrative of the tape in servo track district;
Figure 22 is a process flow diagram of describing the embodiment of method of the present invention; And
Figure 23 is to use the detailed illustrative according to the tape-servo track of servo read element of the present invention, with six servo index positions in the servo track that Fig. 2 is provided.
Embodiment
The present invention is just narrated below with reference to the preferred embodiment of accompanying drawing narration, and wherein same numeral is represented same or like.Though the present invention narrates according to the best way that realizes purpose of the present invention, it will be understood to those of skill in the art that and is not violating under the spirit or scope of the present invention, can realize various variations according to these instructions.
With reference to figure 1, a kind of data-storage system 10 is described, for example magnetic tape system.An example of magnetic tape system is IBM 3590 magnetic tape subsystems, wherein can use servo track positioning system of the present invention.A control device 12 is set, transmits data and control signal from main device 14 to it, and transmit data and control signals to main device 14 from it to pass through an interface 16.Control device 12 and a storage arrangement 18, for example random access memory coupling, this storage arrangement is used for canned data, for example is used to change or the predetermined value of the various numerical value of programming.One example of control device 12 comprises IBM RS/6000 processor.One for example the known multicomponent leader tape head 20 in this area comprise a plurality of data read/write elements, with to tape 22 record data with from tape 20 sense datas, with a plurality of servo read element, to read the servosignal that is included in the tracks positioned information that writes down in advance in a plurality of servo tracks on the tape 22.
The reel motor system (not shown) of the tape transport mechanism tape 22 that is along the longitudinal movement, and servo positioning device 24 relative to tape move vertically along a side direction or transverse guidance 20 moves.Control device 12 is coupled with reel motor, and longitudinally controls direction, speed and the acceleration of tape 22.
Data-track on the tape 22 is arranged to parallel, and parallel with servo track.Therefore, when servo positioning device 24 makes servo read element follow servo track, the data-track that the data read/write element tracks is parallel group.If wish to follow the tracks of another data-track of parallel group, magnetic head 20 laterally indexes, so that the identical servo reading component aims at another servo track, or the different servo reading component is aimed at identical or different servo track.
When magnetic head 20 is prepared to shift to the index position of selection, indexing controller 26 is by control device 12 startings, receive the apparent position signal from an independent position sensor 460, and transmit proper signal to servo logic circuit 465, to select suitable servo track, transmit proper signal with timed unit 12 to servo gap selector switch 32, to select suitable servo read element.Independent position sensor 460 is discussed in the U.S. Patent No. 5,844,814 of combination, the position of its indicating head 20 relative fixed reference.As will illustrating, logical circuit 465 operations so that servo read element is positioned at correct servo track, and are followed track according to servo positioning device 24 of the present invention.Logical circuit 465 can comprise PROM, ASIC or the microprocessor of a programming.Magnetic tape system 10 can be two-way, and wherein some element in the read/write element is chosen as a moving direction, and other elements in the read/write element are chosen as the direction that relatively moves.Control device 12 by transmitting signal to read/write gap selecting arrangement 30, is selected the suitable element in the read/write element in addition.According to the present invention, servo track demoder 28 decoding servo-informations, and servo logic circuit 465 determines the positioning error information, and provide locating information to servo positioning device 24, so that the servo read element of selecting is aimed at the servo track of selection.
Figure 19 is together with the prior art servo read element 470 and 480 with effective sensing unit 471 and 481, and two adjacent servosignals 47 being called " edge " and 48 prior art magnetic tape format are described in conjunction with servo track.Comprise two different servosignals in conjunction with the servo track that writes down in advance, a servosignal is in outside track 40 and 42, recording geometry with constant amplitude signal of single first frequency, at the either side of the intermediate orbit 44 of another servosignal, has the recording geometry that between the constant amplitude pulse signal 45 of single second frequency and null spacing wave 46, replaces.
Two servo edges 47 and 48 have been represented." edge " is included in two interphases between the different servo signal.When a servo read element is centered on the servo edge 47 or on the servo edge 48 time, the composite signal of being read by this servoelement is the peak signal that comprises that the first frequency signal combines with the second frequency pulse signal, alternately comprises the minimum signal that the first frequency signal combines with spacing wave.If servo head correctly is centered on the edge of adjacent servo track, this situation is called " centering edge than ", and is in conjunction with first and the twice of the amplitude of spacing wave in conjunction with the amplitude of first and second frequency signals.This amplitude ratio is called 1/2 ratio.In conjunction with U.S. Patent No. 5,448,430 explanations servo track figure discussed above, and narrate a kind of peak detection that uses and determine that the track of minimum and maximum signal follows servo positioning system.
Typically, be provided with servo buffer zone 500 and 501, avoid data- track district 502 and 503 The noise that produced with protection outside track 40 and 42 in conjunction with servo track 40-44.Prior art servo read element 470 and 480 has minimum possible effective sensing unit 471 and 481, to increase the signal of peak detection to noise ratio.
Prior art servo track edge 47 and opened a preset distance 490 in 48 minutes is used for the manufacturing of tape and servo track.Therefore, only allow two index positions, one of respectively be centered in edge 47 and 48.Increase data-track density by other servoelement being set, so that other reading components can be to the index position index at the deviation post place.This ability is subjected to the restriction of manufacturability of the servo read element of precision offset.
As discussed above, be desirable to provide other data-track.Conventional method is by being provided with less and together near servo (and data) track of location, providing the more accurate location of servo head.Yet becoming is difficult to use identical servo read element, providing back compatible to the data storage medium with available data capacity level, so that avoid must be being recorded in all copying datas on the existing medium to new medium.
Therefore, illustrated as Figure 20, according to the present invention, servo track is constant, but data-track is with the more densely covered location of putting.
Particularly, comprise two outside tracks 40 of prior art and 42 in conjunction with the servo track that writes down in advance, they have the recording geometry of the constant amplitude signal of single first frequency, either side at intermediate orbit 44, recording geometry replaces between constant amplitude pulse signal and null spacing wave, so that two servo edges 47 and 48 to be provided.Edge 47 and opened preset distance 490 in 48 minutes.Yet now, data-track is aimed at, so that servoelement opposite edges 47 or 48 displacements, so that higher track density is provided.For example, displacement is aimed at and can be arranged to along straight line 55-58, they leave along either direction the about intermediate orbit 44 of servo edge center line width 1/4th, four index positions are provided.In order to make the data read/write element be centered in " 0 " and " 3 " index position, servo read element must be arranged in position 505 or position 508, and will read the minimum signal of about 3/4 amplitude with peak signal, and in order to make the data read/write element be centered in " 1 " and " 2 " index position, servo read element must be arranged in position 506 or position 507, and will read about 1/4 minimum signal of peak signal.
Therefore, single servoelement is followed the tracks of four servo index position 55-58 now, rather than follows two servo edges 47 and 48, and the packing density of existing servo track is doubled effectively.In addition, as prior art, can make the index of reference servo read element, and the present invention will allow the data-track doubled in density.
Figure 23 illustrates an alternative embodiment of the invention.At " 0 " or " 1 " index position, servoelement is arranged in the position 600 that is centered in servo edge 47, or is centered in the position 601 of servo edge 48.The other index position of adjusting to a line is provided, so that servoelement opposite edges 47 or 48 displacements, 1/3 the straight line 612-615 that departs from the width of servo edge 47 or 48 about intermediate orbits 44 along either direction arranges.As a result, the index position number becomes six.
In order to make the data read/write element be centered in " 2 " and " 5 " index position, servo read element must be arranged in position 602 or position 605, and will read the minimum signal of about 5/6 amplitude with peak signal, and in order to make the data read/write element be centered in " 3 " and " 4 " index position, servo read element must be arranged in position 603 or position 604, and will read the minimum signal of about 1/6 amplitude with peak signal.
The either side of the energy imagination at the edge comprises other displacements of a plurality of index positions, and they require the detection of accurate amplitude ratio.Concrete amplitude is than being function by the distance that effective sensing unit covered of servo read head etc.
With reference to Figure 20, according to the present invention, effective sensing unit 510 of servo read element is roughly extending on the distance of quadrature with the edge, and this distance is not more than and is whole preset distance 490 haply.Therefore, the effective sensing unit of servo read element is enough to extend on two both distances of different recording servosignal of an edge sensing at one, and in the sensing different recording servosignal no more than two.
Particularly, distance sensing 510 is greater than the twice of index position displacement, and be included in edge separately preset distance roughly 80% and roughly between 100%.
Obvious any very noisy will cause the amplification of the minimum signal at position 506 or 507 places, position, and any noise will cause maximum and the minimum signal that is difficult to distinguish position 505 or 508 places, position.Therefore, in addition with reference to figure 1, the decoding of servosignal is finished by servo decoding device 28 with as the method for the present invention that Fig. 4 to Figure 18 painted.
Fig. 4 explanation is according to servo track positioning system of the present invention, the analog servomechanism signal that is used for the servoelement place of reading head 20, it has a servo track demoder 28, the analog servomechanism conversion of signals is become the asynchronous digital sampling of signal in AFE (analog front end) 65, and the decoding of the 66 pairs of digital samplings of digital servo track demoder, and determine the amplitude of the envelope of the minimum represented by digital sampling and peak signal.Servo positioning device 24 is the servoelement of positioning head 20 then, thereby according to decoding positioning signal location read/write element.Therefore, servo track demoder 28 decoding servo positioning information, and provide locating information to servo positioning device 24, so that the servo read element of selecting is aimed at the index position of selection,, read/write element wishes data-track so that suitably being aligned in.
A plurality of digital servo track demoders of Fig. 5 key diagram 4 respectively comprise an envelope follower 70 and a minimum/maximum detector 71.Envelope follower 70 respectively receives the asynchronous digital sampling of the different servo element of related AFE (analog front end) from homologous lines 72-74.
According to the present invention, or the control device by Fig. 1, or the separately microprocessor by Microprocessor Interface 80 places, provide different programmable values to the servo track demoder on online 78, then can utilize various media, for example have different magnetic characteristics (may cause), or have the tape of different servo or packing density (as mentioned above) owing to material is different.Switch 82 operation Port Multipliers 83 provide suitable decoding locating information with the servo positioning device to output terminal 84.
Fig. 6 A and Fig. 6 B explanation is respectively at the waveform of the simulating signal of the servo transducer output at the position 61 of Fig. 3 and 63 places.Therefore, in Fig. 6 A, in of the position set of servo transducer at Figure 20, is high amplitude by first frequency and second frequency pulse in conjunction with formed pulse 85 and 86, but because only have the sub-fraction of servo transducer to be positioned on the first frequency, so be unusual low amplitude value in conjunction with formed pulse 87 by first frequency and spacing wave.Though distinguish pulse easily, be difficult to measure the accurate ratio of pulse when noise is arranged, therefore be difficult to survey the exact position of servo transducer.
In Fig. 6 B, in of the position set of servo transducer at Figure 20, is high amplitude by first frequency and second frequency pulse in conjunction with formed pulse 90 and 91, as first frequency and spacing wave in conjunction with formed pulse 92, because servo converter mainly is positioned on the first frequency.Therefore, be difficult to distinguish the pulse when noise is arranged, and therefore be difficult to survey the exact position of servo converter.
Speak briefly, in addition with reference to figure 4 and Fig. 5, digitizing difference pulse of the present invention provides the amplitude of the envelope of pulse separately then, so that can determine ratio.The signal sampling of asynchronously servo head being read at the digital servo detector of AFE (analog front end) 65.Envelope follower 70 receives the asynchronous digital sampling, survey and provide the output of largest enveloping line, with the amplitude of the peaked packet of pulses winding thread of measuring the asynchronous digital sampling, and survey and provide the output of minimum envelop line, with the amplitude of the packet of pulses winding thread of the minimum value of measuring the asynchronous digital sampling.
" DROPOUT " threshold detector receives the asynchronous digital sampling, and surveys the asynchronous digital sampling that receives and do not satisfy " DROPOUT " threshold value relevant with the maximum impulse envelope, and " DROPOUT " Threshold Detection signal is provided." ACQUIRE " explorer response " DROPOUT " Threshold Detection, to survey the minimum envelop line of envelope detector, it provides the output of minimum envelop line." DROPOUT " surveys difference minimum envelop line and largest enveloping line, and permission in minimum/largest logical circuit 71 to the measurement of minimum envelop line.Therefore, the largest enveloping wire spoke value of measurement is exported the lateral attitude of representing servo head with the ratio of the minimum envelop wire spoke value output of measuring.The specific embodiment of Fig. 7 to Figure 18 has described in detail and should use.
In addition, with reference to Figure 21, in 20, separate a plurality of servo read element 520-522, with two unlike signals of each corresponding edge sensing at servo track 525-527.So servo read element is average to two unlike signals quilts of inductive sensing separately, to reduce The noise.
With reference to figure 1, Figure 20 and Figure 23, by servo decoding device 28 and servo read element, the logical circuit 465 of for example reading component 505 couplings is two sensitive servo signals relatively, to determine the ratio between them.Logical circuit determine then the sensitive servo signal relatively than and predetermined than between error.Predetermined ratio be centering edge amplitude than or along predetermined direction feel relieved relatively predetermined migration, the hope of the transducing signal that one of predetermined index position that is included in institute's sensing is located and the expection ratio of edge amplitude ratio.In Figure 20, predetermined index position 505-508 is edge dislocation relatively separately all, and in Figure 23, index position 602-605 displacement, and 1/2 ratio deviation of amplitude opposite edges, as discussed above.Logical circuit provides and definite error output signal related to servo positioning device 24.Output signal is discerned the servo position error of relative predetermined index position, and servo positioning device 24 moves along the direction that reduces servo position error and have 20 of servo read element 505-508 or 600-605, thereby follows servo index position.
With reference to figure 1 and Figure 20, identical at index position 505 with the servosignal of 508 place's sensings, but the direction of necessary slip-on head 20 is opposite in order to make the centering of servo read element relative indexing position.Similarly, identical at index position 506 with the servosignal of 507 place's sensings, but the direction of necessary slip-on head 20 is also opposite in order to make the centering of servo read element relative indexing position.
With reference to figure 1 and Figure 23, identical at edge index position 600 with the servosignal of 601 place's sensings, identical at index position 602 with the servosignal of 605 place's sensings, and it is identical with the servosignal of 604 place's sensings at index position 603, but in all cases, the direction of necessary slip-on head 20 is opposite in order to make the centering of servo read element relative indexing position.
With reference to figure 1, independent position sensor 460 is set, so that coarse positioning information to be provided.According in conjunction with U.S. Patent No. 5,844,814 independent position sensor 460 sensing heads 20 a relative reference, for example current apparent positions of the point of fixity of proximity heads.
According to the present invention, coarse positioning information can be two any that select in the level.In one embodiment, in addition with reference to Figure 20 and Figure 23, independent position sensor 460 coarse positioning information indications is current aims at servo read element, and by the edge 47 or 48 of the servo track of servo read element detection.So index position by between two servosignals relatively than determining.Particularly, logical circuit 465 determine relatively than, and according to relatively bigger than definite which sensitive servo signal.The logical circuit response is determined than big servosignal, selects predetermined ratio, with first or second sense of displacement when leading edge of servosignal in the middle of relative servo track, indicates current predetermined index position.
Select among the embodiment at one, the indication of independent position sensor 460 coarse positioning information is current aims at servo read element, and by the index position 505-508 of Figure 20 of servo read element detection, or the index position 600-605 of Figure 23.
When wanting labour contractor 20 to move on to the index position of selection, indexing controller 26 is by control device 12 startings, receive the apparent position signal from independent position sensor 460, and transmit proper signal to servo logic circuit 465, to select suitable servo track, transmit proper signal with timed unit 12 to servo gap selector switch 32, to select suitable servo read element.
Logical circuit 465 is determined current index position indication, and the predetermined index position of response input identification, at first point to the direction of the index position of input identification in four predetermined index positions along current index position, the operation location is servo 24, thereby selects the index position of input identification.Logical circuit is selected the predetermined ratio of the selected index position of expression.Then, logical circuit 465 determine relatively than and the predetermined ratio selected between error, then servo 24 along the direction operation location that reduces servo position error, thus follow the index position of selection.
Figure 22 illustrates an embodiment of method of the present invention.With reference to figure 1, receive input from control device 12 in addition, and in the step 542, the predetermined index position is discerned and selected to servo track demoder and servo logic circuit 465 in the step 540.As go on foot shown in 545, expression can be selected a plurality of servo read heads average, or uses single read head.Selection wherein will be made according to the identification of the type of correct 20 type and medium, and go on foot 545 and represented the information related with this identification.
If only use a servo read element, " 1 ", then in the step 547, servo read element is located no more than two in the sensing different recording servosignal at one of edge.Sensing step one less than and be sensing on the distance of the whole preset distance between the edge haply.Particularly, wherein index position is to separate 25% of the preset distance at edge with the displacement at one of edge haply, and the distance sensing of servo read element is roughly 80% and roughly between 97% of preset distance.
If in the step 545, use more than an element, "＞1 ", then reading component no more than two in each corresponding edge sensing different recording servosignal of step 548 at servo track separately.In the step 549, the unlike signal of each self-sensing of sensing reading component is by average.Then, in the step 550, servo decoding device 28 is relatively or from single different servo signal in step 547, or from the average different servo signal in step 549, to determine the ratio between the servosignal.
By same sequence, independent position sensor 460 is the current apparent position of the relative reference of servo read element of sensing head 20 independently, current apparent position or indication are going on foot the 560 current predetermined index positions of being surveyed by servo read element, or indicate by servo read element at the edge that goes on foot the middle servosignal of 561 servo tracks of being surveyed.According to the leading edge of surveying in the step 561 of working as, two unlike signal (S that logical circuit 465 compared from the step 550 in the step 565
1) and (S
2) ratio, to determine which is bigger in two signals.Bigger signal (S
1) or (S
2) direction indication, work as leading edge with the indication of servosignal in the middle of the relative servo track, indicate the current predetermined index position of first sense of displacement (step 566) or second sense of displacement (step 567).
Therefore, step 560, steps 566 or 567 indication are by the current predetermined index positions of servo read element sensing.In the step 570, use the predetermined index positions of selecting in the step 542, so that if any, select to comprise along selected direction from the centering edge than the predetermined ratio that predetermined migration is arranged.In the case illustrated of Figure 20, the amplitude of expression skew than will be expression 1/4 preset distance 490 that leaves center signal 44 along a direction 505 or 508 displacement roughly 3/4, and be to represent to leave roughly 1/4 of 1/4 inside displacement of edge along other direction 506 or 507.In the example of Figure 23, the predetermined edge index position of selecting in the step 570 600 or 601 that is compared to comprises roughly 1/2 amplitude ratio, comprise roughly 5/6 amplitude ratio for index position 602 and 605,1/3 displacement of center signal 44 is left in expression along a direction, and comprising roughly 1/6 amplitude ratio for index position 603 and 604, the displacement of 1/3 inside preset distance 490 of edge is left in expression.
If 20 the current index position that is not positioned at selection of servo read element, logical circuit 465 is at first operated servo positioning device 24 in the step 575, servo read element is moved on to the index position of selection.Repeat to go on foot 560, step 566 or go on foot 567, up to the servo read element index position selected of coarse positioning correctly.
In case the servo read element coarse positioning is at the index position of selecting, track is followed beginning.In the step 580, logical circuit 465 after two sensitive servo signals in step 550 relatively than comparing with the selection ratio in step 570.This relatively determines the servo position error of selected relatively index position.Logical circuit 465 is then at steps 585 operation servo positioning device, so that servo read element moves along the direction that reduces servo position error.
Step 547 or go on foot 548, and step 550, step 580 and go on foot 585 and continue to follow selected predetermined index position then.
Therefore, the present invention has increased the track density of the data-track of data storage medium, utilize existing medium servo track simultaneously, so that can operational servo, thereby as before, utilize the servo track locating information for existing medium, and utilize identical servo track locating information in more accurate mode, with higher orbit density access data track.
Though understood the preferred embodiments of the present invention in detail, it will be apparent to those skilled in the art, under the scope of not violating as following claims of the present invention, may various changes and adaptation appear to these embodiment.
Claims (9)
1. method that is used to survey the servo positioning of a relative servo track, described servo track has two edges at least, each described edge comprises an interphase between two different record servosignals, described edge is at the relative side of a described record servosignal in centre, described edge is a preset distance separately, and described method comprises step:
Locate no more than two in the described different recording servosignal of sensing at one of described edge, described sensing step is sensing on a distance with one of the described quadrature at described edge, described distance is left the twice of one of the described displacement at described edge greater than the predetermined index position, and the described preset distance that separates described edge 80% and 100% between;
More described two sensitive servo signals, with determine between them relatively than; And
Respond described comparison step, determine described sensitive servo signal described relatively than and one predetermined than between error, described predetermined ratio comprises one along feel relieved the relatively predetermined migration of edge ratio of predetermined direction, described predetermined one of described parallel than one of identification and described edge, and the predetermined index position of one of the described displacement at described relatively edge, the described servo positioning of the described relatively servo track predetermined index of described error detection position.
2. the method for claim 1, be used to survey the described servo positioning of the described servo track that a plurality of relatively almost parallels separate, the described servo track that separates is spaced from each other a distance, described distance described separately much bigger than between described two edges of each described servo track, wherein:
Described sensing step is included in described two the described unlike signals of each corresponding edge place's sensing of described servo track in addition; And
Described comparison step comprises described two unlike signals to inductive sensing of each described servo track average in addition, with determine between described two average unlike signals described relatively than.
3. the method for claim 1 comprises step in addition:
The current apparent position of the relative reference of the described sensing step of sensing independently, servosignal works as leading edge in the middle of the described servo track that described current apparent position indication is detected.
4. the method for claim 3, be used to survey the described servo positioning of the predetermined index position of described relatively servo track, servosignal was along first or second sense of displacement displacement respectively when leading edge of leaving described indication in the middle of described predetermined index position was described relatively, and wherein said determining step comprises step in addition:
By described relatively bigger than definite which described sensitive servo signal; And
The described big servosignal of determining in the response determining step is selected described predetermined ratio, as servosignal in the middle of the described relatively servo track, along leaving described first or described second sense of displacement of described indication when leading edge, indicates current predetermined index position.
5. the method for claim 1, be used to survey the described servo positioning of the predetermined index position of described relatively servo track, servosignal left first or second sense of displacement displacement respectively at each described edge in the middle of edge, described predetermined index position was described relatively, and described method comprises step in addition:
The current apparent position of the relative reference of the described sensing step of sensing independently, the current location of the described predetermined index position of the described servo track that described current apparent position indication is detected.
6. method that is used to follow the servo index position relevant with servo track, described servo track has two edges at least, each described edge comprises an interphase between two different record servosignals, described edge is at the relative side of a described record servosignal in centre, described edge is a preset distance separately, described servo index position and described edge one of described parallel, and one of the described displacement at described relatively edge, described method comprises step:
Locate the described different recording servosignal of sensing at one of described edge no more than two, described sensing step is sensing on a distance with one of the described quadrature at described edge, described sensing step distance is left the twice of one of the described described displacement at described edge greater than described predetermined index position, and the described preset distance that separates described edge 80% and 100% between;
More described two sensitive servo signals, with determine between them relatively than;
Respond described comparison step, determine described relatively sensitive servo signal described relatively than and one predetermined than between error, described predetermined ratio comprises one along feel relieved the relatively predetermined migration of edge ratio of predetermined direction, to determine the servo position error of described relatively servo index position; And
Servo along the location of direction operation that reduces described servo position error, thus described servo index position followed.
7. the method for claim 6 is used to follow the described servo index position of a plurality of relatively parallel described servo tracks, and described servo track is a distance separately, described distance greater than between described two edges of each described servo track described separately, wherein:
Described sensing step is included in described two the described unlike signals of each corresponding edge place's sensing of described servo track in addition; And
Described comparison step comprises described two unlike signals to inductive sensing of each described servo track average in addition, with determine between them described relatively than.
8. method that is used to select and follows one of a plurality of predetermined index position of a servo track, input is responded, to discern a described predetermined index position, described servo track has two edges at least, each described edge comprises an interphase between two different record servosignals, described edge is parallel to each other, and on the relative side of a described record servosignal in centre, described edge is a preset distance separately, servosignal in the middle of each position of described a plurality of predetermined index position is described relatively, along first or second sense of displacement that leaves each described edge displacement respectively, described method comprises step:
Locate no more than two in the described different recording servosignal of sensing at one of described edge, described sensing step is sensing on a distance with one of the described quadrature at described edge, described sensing step distance is left 2 times of one of described described displacement at described edge greater than described predetermined index position, and the described preset distance that separates described edge 80% and 100% between;
The current apparent position of the relative reference of the described sensing step of sensing independently;
Respond described independent sensing step, the current location of indication in described a plurality of predetermined index position of described sensing step sensing;
Respond described current index position indication step, and the predetermined index position of described input identification, at first point to the direction of the described input recognizing site in the described predetermined index position along the current index position of described indication, it is servo to operate a location, thereby selects the described recognizing site of described predetermined index position;
Respond described sensing step, more described two sensitive servo signals, with determine between them relatively than;
Respond described comparison step, determine described relatively sensitive servo signal described relatively than and one predetermined than between error, described predetermined ratio comprises a described predetermined direction along the described chosen position of described predetermined index position, the predetermined migration of relative centering edge ratio, thereby the servo position error of the predetermined index position of definite described relatively selection; And
The described location of direction sequential operation of described servo position error is servo along reducing, thereby follows the predetermined index position of described selection.
9. method that is used to select and follows one of a plurality of predetermined index position of a servo track, input is responded, to discern a described predetermined index position, described servo track has two edges at least, each described edge comprises an interphase between two different record servosignals, described edge is parallel to each other, and on the relative side of a described record servosignal in centre, described edge is a preset distance separately, servosignal in the middle of described a plurality of predetermined index position is described relatively, along first or second sense of displacement that leaves each described edge displacement respectively, described method comprises step:
Locate no more than two in the described different recording servosignal of sensing at one of described edge, described sensing step is sensing on a distance with one of the described quadrature at described edge, described sensing step distance is left 2 times of one of described described displacement at described edge greater than described predetermined index position, and the described preset distance that separates described edge 80% and 100% between;
The current apparent position of the relative reference of the described sensing step of sensing independently, described current apparent position indication is detected described in the middle of servosignal work as leading edge;
The servosignal of more described two sensings, with determine between them relatively than;
By described relatively bigger than definite which described sensitive servo signal, the sense of displacement when leading edge of the described relatively indication of the described sensing step of described definite indication;
Respond described independent sensing step, and described sense of displacement determining step, use indication of described edge and described analogy to determining, by the described sense of displacement when leading edge of described relatively indication, the current location in the described predetermined index position of indication sensing in described sensing step;
Respond described current index position indication step, and the predetermined index position of described input identification, at first point to the direction of the described input recognizing site in the described predetermined index position along described current index position, it is servo to operate a location, thereby selects the described input recognizing site in the described predetermined index position;
Respond described comparison step, determine described relatively sensitive servo signal described relatively than and one predetermined than between error, described predetermined ratio comprises a described predetermined direction along the described chosen position of described predetermined index position, the predetermined migration of relative centering edge ratio, thereby the servo position error of the predetermined index position of definite described relatively selection; And
The described location of direction sequential operation of described servo position error is servo along reducing, thereby follows the predetermined index position of described selection.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US09/413,327 US6525898B1 (en) | 1999-08-03 | 1999-10-07 | Detection of indexed servo positions displaced from servo track edges |
| US09/413,327 | 1999-10-07 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1291772A CN1291772A (en) | 2001-04-18 |
| CN1244109C true CN1244109C (en) | 2006-03-01 |
Family
ID=23636819
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB001292234A Expired - Fee Related CN1244109C (en) | 1999-10-07 | 2000-09-29 | Index servo position search of offset servotrack edge |
Country Status (4)
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| JP (1) | JP3650316B2 (en) |
| KR (1) | KR100376745B1 (en) |
| CN (1) | CN1244109C (en) |
| SG (1) | SG96570A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ME01738B (en) | 2001-10-15 | 2008-09-29 | Koninl Philips Electronics Nv | Record carrier and apparatus for scanning the record carrier |
| JP5766266B2 (en) * | 2013-12-20 | 2015-08-19 | 日立マクセル株式会社 | Magnetic tape device, data recording method, magnetic tape |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4519007A (en) * | 1982-12-08 | 1985-05-21 | Burroughs Corporation | Servo-track position detection systems |
| US5448430A (en) * | 1993-08-05 | 1995-09-05 | International Business Machines Corporation | Track following servo demodulation |
| JPH09139035A (en) * | 1995-11-13 | 1997-05-27 | Toshiba Corp | Disk recording and reproducing system and its head positioning control method |
| JP3257939B2 (en) * | 1995-11-21 | 2002-02-18 | 富士通株式会社 | Disk drive and head positioning control method for disk drive |
| US5946159A (en) * | 1996-11-27 | 1999-08-31 | International Business Machines Corporation | Servo edge correction using edge samples taken by independently positioned servo elements |
| JP3871081B2 (en) * | 1997-02-26 | 2007-01-24 | 富士通株式会社 | Servo track writer and magnetic disk drive |
| JP3758317B2 (en) * | 1997-07-09 | 2006-03-22 | ソニー株式会社 | Data recording and / or playback device |
| JPH1153851A (en) * | 1997-08-05 | 1999-02-26 | Matsushita Electric Ind Co Ltd | Magnetic disc and magnetic disc device |
-
2000
- 2000-08-22 JP JP2000250779A patent/JP3650316B2/en not_active Expired - Fee Related
- 2000-09-25 SG SG200005496A patent/SG96570A1/en unknown
- 2000-09-29 CN CNB001292234A patent/CN1244109C/en not_active Expired - Fee Related
- 2000-10-06 KR KR10-2000-0058776A patent/KR100376745B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| CN1291772A (en) | 2001-04-18 |
| KR20010050891A (en) | 2001-06-25 |
| JP3650316B2 (en) | 2005-05-18 |
| JP2001110026A (en) | 2001-04-20 |
| SG96570A1 (en) | 2003-06-16 |
| KR100376745B1 (en) | 2003-03-19 |
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