Summary of the invention
The purpose of this invention is to provide a kind of device that can the cancellation pattern deviation.
For this purpose, device of the present invention is characterised in that, pen recorder can be along track mobile significantly initial position on distance of selecting at random within the predetermined threshold, and/or revise its expression mode.The present invention is also based on the following fact, and that is exactly that the deviation of figure depends primarily on and is recorded in the track with the relation between each piece on the part, if write down identical or extremely similar piece, deterioration will be accelerated significantly.Its length is considered to enough usually for the longest a small amount of figure displacement of using that writes several times (two to three times) of mark in figure.But surprisingly, the micro-displacement of this about 32 channel bit is actually not enough, also finds simultaneously, wants the obvious displacement about 128 bits to be only effectively at least.
For this purpose, the feature of the inventive method is along track mobile significantly initial position on a distance of selecting at random within the predetermined threshold, and/or revise its expression mode.
For this purpose, write down according to the method described above according to information carrier of the present invention.
For this purpose, the feature of readout device of the present invention is, begins the sense information piece with readout device from the position of obviously moving on the certain distance of selecting at random within the predetermined threshold, and/or according to the expression mode of revising message block is decoded.
Result according to measure of the present invention is, is recorded in that the figure of various piece is constantly to change on the track, thus the acceleration of just having offset deterioration.One of its advantage is the serviceable life that has prolonged information carrier.This advantage is effective especially when using habitual file management system, and file control information wherein always is overwritten at the same section of track.
The feature of an embodiment of apparatus of the present invention is can recover its expression mode when reading from message block.Its advantage is that the recovery to information is irrelevant with the information about the expression mode that is stored in other places from the message block of reading.
The feature of another embodiment of apparatus of the present invention is to comprise in the expression way with the scrambler key and carry out scrambler that this scrambler key is included in the message block.Any correlativity that its advantage is to prepare to be recorded between the message block on the same position has been reduced by scrambler.
An embodiment again of apparatus of the present invention is characterised in that its expression mode is included in the pseudo-data of variable number included in the message block, can discern this pseudo-data when reading.The advantage of doing like this is the variable number that can constantly increase pseudo-data, and figure that might be identical in the message block can be recorded in different positions at every turn.The result who increases pseudo-data before the information in message block makes original message block major part be rewritten, thereby invalid part no longer can be read out.
Another embodiment according to apparatus of the present invention is characterised in that, its expression mode be included in the message block front first variable number pseudo-data and in the pseudo-data of second variable number of message block back, and the first and second variable number sums are constant basically.Its advantage is that the total length of message block is constant basically, so just can be in fixing position record, the information content then is recorded in the position of random variation.
Another embodiment according to apparatus of the present invention is characterised in that its expression mode comprises the rotation of carrying out on the information distance that is selected at random in message block.The information of staying message block one side is added to opposite side.Its advantage is, does not need the exceptional space that coils for rotation information.This point is useful especially when adopting synchronizing pattern, and these synchronizing patterns and information move together, therefore can always not be in same position.
Another embodiment according to apparatus of the present invention is characterised in that its expression mode is included in the distance of selecting at random in each message block.Its advantage is to draw the distance of rotation information simply.This point is adopting and useful especially during synchronizing pattern that information moves together, and this is because of the quantity of information that can determine the first synchronizing pattern front and/or synchronizing pattern back, end when reading.
Embodiment
But Fig. 1 a represents a kind of disc-shaped information carrier 1 of rewriting type.This information carrier comprises the track 9 that is used to write down, and this track is arranged to the spiral figure of round.Except spiral, also can be arranged to concentric circle.Indicate track 9 with a kind of servo figure on information carrier, for example available a kind of pregroove marks 4 is started read/write head in servo figure, makes its pursuit path during scan operation.This servo figure also can constitute with for example neat spirte of dividing, and this spirte can periodically produce signal in tracking servo.Fig. 1 b represents the b-b cross section along information carrier 1, and the substrate 5 among the figure is covered by a rewritable recording layer 6 and a hyaline layer 7.The part that pregroove marks 4 also can be arranged to raise, or different with the material character that uses around it.Recording layer 6 can come recording records blocks of information with optical mode or magnetic-light mode by a kind of equipment.Message block on the information carrier is represented with pictorial symbolization.If in track, form figure, each mark be by one or more Writing power constant or variable write pulse shaping, the size of power generally depends on the length of mark.The parameter that writes such as Writing power, umber of pulse, variation, duty cycle etc. need be harmonious with the character of main material in the information carrier.For example, erasable CD is exactly a kind of information carrier of writing type, is covered with one deck phase-change material thereon.Book numbers that the people showed such as Bouwhuis is ISBN 0-85274-785-3, and title is for finding the explanation of reading and using pregroove marks about CD in " Princles of Optical Disc Systems " book.
Fig. 1 c and 1d represent the pregroove marks of two routine periodic modulation (swing).This swing can produce a kind of additional signal when tracking servo picks up.This swing for example is to carry out warbledly with a kind of auxiliary signal, comprises the supplementary of coding in this auxiliary signal.The address information that comprises the position on the indication course length direction in the supplementary.In EP-0397238 number, can find the relevant explanation of the record carrier that comprises this supplementary.According to the address information on this information carrier, just can derive the initial position that is used for writing information blocks in the track.
The present invention can also be applied to other information carriers, and the position along track on this carrier is determined by diverse ways, for example passes through independently reference pattern, or by being recorded in the figure on the information carrier in advance.But the present invention can also be used for the rewriting type information carrier of other structures, for example light belt (optical tape).Can provide address information for these information carriers by different modes, for example by the information on the auxiliary track.
Fig. 2 represents duplicate record effect and the initial position relation curve between moving.The situation that this curve representation is such, but promptly identical message block always is recorded in a specific part on the rewriting type information carrier.Message block is that the mark by the different length that can read photographically constitutes, and its length difference is a multiple that is referred to as the fixed range of channel bit always.The quality of read output signal is normally estimated according to for example shake or the eye pattern picture of read output signal (eye pattern).When duplicate record, the initial position of message block on the course length direction always moves a distance at random within boundaries for certain.'s distance between these boundaries of unit along the numeral of X-axis 31 with the channel bit.A number of times that specific part had write down along Y-axis 32 (using logarithm) expression track.When specific quality deterioration occurring, just find a measurement point by duplicate record.But pulse-position modulation (PPM) habitual in known rewriting type register system only writes down some brief marks with the mode that distributes.Yet, when adopting pulse length modulation (PLM) in order to increase information density, long mark often appears.The EFM+ chnnel coding of using in high density CD described in the PCT/IB95/00070 is exactly an example with PLM of high information density.Demonstrate by measurement,, the form that this phenomenon is strengthened will occur if figure is to be made of the continuous recording mark that elongates.In addition, when particularly comprising low frequency component in the average frequency spectrum of recording geometry, also this phenomenon can appear.Therefore, the present invention just in time is fit to be used in combination with PLM.Relation between the figure difference degree in the time of can reflecting the record number of times of process with duplicate record at every turn through the curve 33 of each measurement point.Surprisingly, if this relation demonstrates the identical figure of duplicate record on one (basically) of information carrier fixing position, operable record number of times will reduce.In addition, in order to increase the service life as far as possible, need mobile significantly initial position.Opposite with situation about expecting, a small amount of displacement of about 32 channel bit (first measured value 34) expression really can only have a spot of number of rewrites.This displacement is several times of the longest mark that uses among the PLM, and long mark can not overlapped.Have among the CD-E of reality of figure of 17 channel bit at an information byte, the longest mark is 11 channel bit.Like this, to amount to the displacement of 34 channel bit should be enough for two information bytes.Yet only (second measured values 35 at 128 bit places) just tangible improvement can occur when bigger displacement reaches 100 bits basically.And the displacement (the 5th measured value 36) that surpasses 1000 channel bit magnitudes can not provide further improvement to tested information carrier.
Fig. 3 represents to be used to read and/or write down according to the present invention the device of disc-shaped information carrier.This device comprises code device 52 and a read/write device 57, be used to write and/or sense information carrier 1 on message block.Information is added to input end 51, and is converted into write signal in code device 52, and information is to represent with predetermined mode in message block.Write signal is provided for read/write device 57.Come activation bit carrier 1 to rotate with drive unit 58.Read/write device 57 usefulness light beams 56 come track while scan 9, and with the marker graphic writing information carrier of representative information.Adopting the servo-drive system (not shown) of habitual form that read/write device 57 is positioned on the track 9 during the scan operation.System controller 59 is controlled scanning to information carrier 1 by drive unit 58 and servo-drive system.In general, this device also will comprise decoding device 53, is used for the figure recovering information of reading from read/write device 57.Produce information after recovering at output terminal 54 then.The device that only is used to write down can not comprise decoding device 53 and output 54, and the device that only is used to read can not comprise code device 52 and input 51.This device can further include the demodulating equipment 55 that is used to recover address information.The servosignal that produces when track while scan is provided for demodulating equipment 55, with 55 pairs of servosignal demodulation of demodulating equipment, thus the auxiliary signal of recovering.Demodulating equipment 55 is address acquisition information from auxiliary signal, and this information is provided for system controller 59.
According to the present invention, writing station 52,57,59 are used to writing information blocks, and its writing mode is not write identical figure on the same position in a certain specific region of track as far as possible.So first measure is, the initial position of message block that will be prepared record by system controller 59 is by always moving a distance with respect to the initial position of demarcating.This distance is optional, but must be within the predetermined border, otherwise the message block of front or back is partly rewritten.In addition, compare with the Graph Distance in the chnnel coding, this distance is very big.But, should between piece and piece, keep enough spaces, so that can realize this displacement for corresponding rewriting type information carrier.This point can be achieved like this, for example can be by be message block and the enough spaces of maximum (peak-peak) displacement reservation between the initial position of the demarcation of stipulating in the modular system standard.Displacement with 1000 bits is an example, and it can make EFM+ coding (8/16 data/channel bit) and 2k byte information piece and ID synchronization zone etc. lose about 3% information density, and the message block of 32k byte is then lost information density about 0.2%.The effect that in Fig. 4, has further shown first measure.
Second kind of measure is the expression mode of constantly revising information.Need to adapt with code device 52, selected reorganization mode is always different for this reason.Produce the key of an indication expression mode by system controller 59, thus this key decoding also is essential for message block when reading.For example, the random bytes that can produce 256 keys can be used as key.Or also can use continuous key.These keys also can play the effect of the counter of multiplicity, and it represents the degree that the part of track is frequently write down with this key.When reaching some maximal values, just can stop this specific part that uses track, in order to avoid when after this reading, produce error.In order to produce continuous key, need to use a kind of system, wherein the most of bit between continuous key all is different.This key can be stored in the another location in the message block or on the information carrier, for example is stored in the central area.Important problem is to make this coding can prevent to greatest extent to occur error in the readout, if mistake appears in key, information just again can't have been recovered.Can protect this key with habitual error correcting code for this reason, also can the several points in message block on duplicate record.Another kind may be that key is stored in the storer of this device (for example in the system controller).Storer can be nonvolatil storer; After this can only read this information carrier with corresponding device thereof.Or also the content of storer may be recorded on the information carrier constantly at each of regulation.
In order to revise the expression mode, can use for example scrambler technology.For this modification, can handle write signal (for example adopting XOR (EX-OR) computing) with a bit stream according to known mode.In order to produce bit stream, need to use a generator circuit, produce bit stream according to key therein.This key can be included in the message block, for example is included among the ID.It should be noted that especially and want and from read output signal, to recover ID with simple mode, because system controller requires promptly to obtain this ID when needs jump to a certain message block.Therefore, can use fairly simple scrambler operation to ID.When scrambler, also can use so-called motor synchronizing scrambler operation.This moment is without any need for clear and definite key, but descrambler can become consistent again after certain bit number of having handled the scrambler signal.As can be seen, when information during, in each write operation,, but use this coding of from the ID of information, deriving, the useful effect that just can not realize ideal herein not with the coding of revising by scrambler.
The another kind of measure that is used for revising the expression mode is to increase a certain amount of pseudo-data in message block, for example comprises the zone of a variable-length when each record in the beginning of message block, fills in to select at random but be the pseudo-byte of fixing in this zone.It after this pseudo-zone the ID district that can discern with fixed form.Like this, in the process of sense information piece, always can find the ID district, and still can write down whole track region, the outmoded or message block that can not re-use of record before so just can not occurring again.Or in variable pseudo-data field of ending increase of message block, the length in the district that holds the record again simultaneously (pseudo-zone+message block content+puppet zone) is constant.This expression mode is the pseudo-data that comprise the pseudo-data of first variable number in the message block front and comprise second variable number in the message block back, and the first and second variable number sums are constant basically.
Three kinds of having schematically shown between the above-mentioned continuous information piece that comprises pseudo-data of Fig. 7 may states.First 71 and second 72 of the information content of demarcation (vertically) position have been represented to have under superincumbent a kind of state.When writing down in track, piece and piece are lateral alignment, thereby overlapping in 80 among a small circle at one.The advantage of overlapping region is, even because of the timing error of reality has caused little positioning error, still can be on track continuous recording.In track, continuous record mark can prevent the interference of servo-drive system and signal Processing.The ending of first 71 information content has a sync mark 73 of representing with thick line.The ending bonding pad 78 that has pseudo-data to constitute in sync mark 73 back, it continues up to the actual ending of record 74.The information content by sync mark 77 and second is followed in second 72 beginning bonding pad 79 that is made of pseudo-data from actual start 75.Zone between the sync mark 77 of first last sync mark 73 and second front is called the connection frame usually.Other connection frames that carry out signal Processing for readout device can be arranged, so that adjust to the new message block that may write down with distinguishing slightly parameter before second the information content.The sync mark that connects the frame front has one and is used to refer to the particular value that connects frame.Connection frame between two continuous information pieces has the length 76 of demarcation, comprising overlay region 80.Middle two other continuous message block 81,82 of state representation, the position of its information content has been moved.First 81 beginning (not shown) has a large amount of pseudo-data, and have complementary a small amount of pseudo-data 84 in its ending, so just can make first 81 total length identical with top state, and the actual information content has been moved a distance+Δ with the ending point.Second 82 beginning of intermediateness has minimum pseudo-data, makes to connect the length that frame 83 has the weak point of trying one's best, and simultaneously, second the information content has been moved a distance-Δ.Below state representation have-first 85 of Δ displacement, therefore a large amount of pseudo-data are arranged in its ending.Second 86 displacement is+Δ that connection frame 87 at this moment is the longest.As mentioned above, Zui Da displacement should be enough big.In concrete instance, the frame between the sync mark can reach 91 bytes, and the byte in above-mentioned EFM+ is represented with 16 channel bit.The maximum Δ that the displacement of 62 bytes (992 bit) can provide is 31.The ending bonding pad 78 that connects frame is 49 bytes, and beginning bonding pad 79 is 50 bytes, and the overlay region of one 8 byte is arranged, and allows two message block to each have the deviations of 4 bytes.So just can make following state have the maximum ending bonding pad of 49+31=80 byte and the maximum of 50+31=81 byte begins the bonding pad, thereby the maximum that just can obtain the 80+81-8=153 byte connects frame 87, and it just in time equals the calibrated length that enlarged by total displacement 91+62=153.Correspondingly, under intermediateness, the minimum of the minimum of 49-31=18 byte ending bonding pad and 50-31=19 byte begins the minimum that the bonding pad can produce the 19+18-8=91-62=29 byte and is connected frame 83.Under above-mentioned situation, these limits of 153 and 29 bytes are the worst states.It should be noted that herein, one or more connection frame is arranged always so that allow servocontrol and signal processing circuit aim at next message block in the real system, these message block are according to writing with last different condition probably in different registers.So these frames can be used in device to reading or writing down and prepare.The present invention obtains displacement and can be without any need for additional card space in conjunction with the mode that connects frame with the pseudo-data of aforesaid increase, thereby can advantageously obtain highdensity information, can not lose memory capacity again.
Above-mentioned these measures can realize independently or with array mode.Adopting the advantage of displacement separately is but that readout device does not need special measure just can read the rewriting type information carrier that writes down according to the present invention.Such playback mode is identical with playback mode read-only or that write information carrier once basically.For computing machine and the multimedia application of using the different types of information carrier, this is an advantage.If the message block of record is fewer, displacement will have influence on information density significantly.Preferably limited displacement and scrambler operation are combined in this case.The scrambler operation can reduce the autocorrelation of the message block that will write down greatly.According to the chnnel coding of selecting, some figure can be continuously fixing, for example the synchronizing pattern in the EFM+ chnnel coding.Like this, limited displacement operation just is enough to guarantee with these graphic recordings on the diverse location of track.If select displacement limitedly, just can on information carrier, realize higher information density.
According to the present invention, the readout device that comprises read/write device 57 and decoding device 53 shown in Figure 3 be used to from the distance of selecting at random within the predetermined threshold by the position of obviously moving on the sense information piece, and/or message block is decoded according to the expression way of revising.The above-mentioned measure that is used for revising the expression mode is that mode according to complementation realizes at decoding device, and position that is shifted significantly and/or connection frame are as shown in Figure 7 handled in conjunction with servo-drive system and decoding device 53 by read/write device.
Fig. 4 is out-of-proportion synoptic diagram of a track, on the initial position after message block wherein is recorded in and moves.The initial position that solid line 41,42 and 43 expressions are demarcated.Their phase mutual edge distance is fixed to 40.The displacement system of different spacing can also be provided in a part of track between the initial position of demarcating in addition.The message block of 44,45 and 46 expression records.As we can see from the figure, first 44 from demarcating initial position, and second 45 than demarcating initial position certain distance that lags behind, and the 3rd 46 before demarcating initial position.So changing at interval between the message block.After writing down several times, will comprise the outmoded information of a part in the spacing, shown in the beginning of last piece 47.Yet, should see in the known register system of writing the type information carrier, having the surplus that some are used to change the message block initial position between piece and the piece.The machinery and the electrical error of the initial position that this surplus (for example 16 bits) occurs in the time of can being used for compensating the opening entry operation.As shown in Figure 2, have been found that this surplus can not offset deviation fully effectively.
Fig. 5 has schematically shown a kind of modification.Adopted the combination of scrambler and two kinds of measures of displacement for this reason.Carry out following steps by system controller 59:
S1: system controller receives the recording instruction of a message block, and determines that is demarcated an initial position.
S2: system controller produces a key at random, and provides it to code device 52, and the indication code device carries out scrambler with this key.This key for example also is included in the message block itself.
S3: system controller adds a distance at random for demarcating initial position.
S4: system controller is positioned at read/write device 57 on the appointed area of track 9, and for example the address information of reading according to demodulating equipment 55 such as comes to arrive the read/write device below at initial position to be calculated.
S5: system controller indication writing station 52,57 is carried out and is write.
The read operation (not shown) is also carried out in a similar manner, at first will recover key from read output signal, and provides it to the anti-scrambling device in the decoding device 53.Then carry out decoding as known readout device.
Fig. 6 has schematically shown rotation (rotating) information in the message block.In first information piece 61, information is placed in the position of demarcation.By convention; the beginning of message block 61 is to comprise RUN-IN (importing) part 63 that can import the importing figure of (run-in) for readout device; specifically be exactly to allow a phaselocked loop (PLL) be locked on the data clock of regeneration; the ending of message block has a GUARD (protection) part 67, in order to avoid abrupt transition is to the information carrier on unwritten part or the figure that has previously write down.A block of information 60 is arranged between RUN-IN 63 and GUARD 67, wherein comprise one or more data block Dn and synchronizing pattern S; In Fig. 6, represented four data block D0 (65), D1, D2, and D3 (66), there is a synchronizing pattern 64 each data block front.Always be recorded in identical position for fear of data block and synchronizing pattern S when the duplicate record, need be when writing down with distance at random of the rotation of the information in the block of information 60 at every turn
a, for example shown in second message block 62 of Fig. 6.This rotation perhaps also can be coiling, can be understood that all bits in the block of information 60 all move towards certain orientation, and in moving, those bits that surpass the border, data field are moved in another borderline white space of block of information.In with 62 message block of representing, data block and synchronizing pattern have been moved
aIndividual channel bit, and the information of last data block D3 has been divided into two parts 68,69.Through after moving, the second portion 69 of last data block D3 can continue up to above end boundaries 70, and is added in first data block of initial boundary back of block of information 60.Obviously, also can on other direction, be rotated, like this will be the D0 separated into two parts.During read operation, displacement
aTo from read output signal, derive, and want the starting point and/or the end points in derived information district 60 simultaneously.This point can realize by for example selection to RUN-IN figure and/or the concrete form of GUARD figure.In addition,
aValue can certainly be included in separately in the message block, preferably is located at the precalculated position with respect to synchronizing pattern.The RUN-IN of message block and/or GUARD part preferably adopt variable figure, otherwise the quality of these parts will worsen quickly than data block portions.For example can in the RUN-IN figure, adopt (variable)
aValue, this RUN-IN can change, and can recover when reading
aOr also can only use
aValue changes the position of synchronizing pattern, and with the scrambler key that for example in RUN-IN part, comprises to remaining data scrambler.In order to read the data block that synchronizing pattern has been moved, preferably include a storer in the readout device, be used for storing the signal of the first synchronizing pattern front, after realizing synchronously to the content decoding of storer.In illustrated second message block 62, can after first's 68 decodings, decode to a part 69 that is stored in the data block in the storer again to last data block D3, this part is affixed on first data block.
If will apart from a select enough big (magnitude of 1000 channel bit is referring to Fig. 2), just can make the very high overwrite performance of message block acquisition with synchronizing pattern.Obviously, for the message block that does not have fixing synchronizing pattern, also be the same, the synchronous decoding of this message block is to realize with different modes when reading.In addition, if a plurality of message block is continuous recording, also can adopt the message block that does not have RUN-IN or GUARD district.Which kind of situation no matter adopts the advantage of this rotation mode to be not need to increase space between the message block, because message block always can be recorded in identical position.
