RECORDING METHOD AND RECORDING APPARATUS

Abstract: A recording method for assigning onto a number of data tracks the recording signals constituted by a sequence of a number of data of an editing unit which are the data of a minimum unit that can be rewritten in order to record them onto a recording medium. The method comprises a step for dividing the data of the editing unit of recording signals into N (an integer of 2 or greater) data, and a step for dividing all of the data tracks into plural numbers and which assigns the divided data to N partial data tracks that are neighbouring among the data tracks with the divided portions as partial data tracks to record the data onto a recording medium.

Description: The present invention relates, in a record reproducing apparatus for video, cassette, recorder or the like, to a method and an apparatus for allocating into a plurality of track portions in parallel tracks data signals to be recorded and composed of a plurality of editing units, each editing unit being the data of a minimum unit capable of rewritting operation. Background Art: Conventionally, in the record reproducing apparatus, a recording method is general which allocates the recording signals into a plurality of data tracks so as to effect the recording operation on a recording medium the recording signals (for example, audio signals and video signals) composed of a plurality of editing unit data. (For example, Richard brush; Design Consideration for the D - 2 NTSC Composite DVTR : SMPTE Journal: 182-193, March, 1988). Here the data in one editing unit of the recording signal is defined to be the data in the least unit to be capable of rewriting operation in the recording of the new signals on the prerecorded part on the recording medium by a certain record reproducing apparatus. For example, assume that the recording signals are video signals, and the data in the editing unit become the data of the video signals of one field or one frame. Conventionally a recording method is provided of allocating the data of a certain editing unit as it is on one data track on the recording medium without dividing the data. The conventional recording method will be described hereinafter. Fig. 10 is a format chart on the recording medium in the conventional recording method. Here a recording method of allocating four editing units of data (the audio signals of four channels) into two data tracks is simply described, with the format of the other portions being not mentioned. As shown in Fig. 10, the data (audio signals of four channels) "A1", "B1", "C1", "D1" of four editing units are allocated to the portions of 101, 102, 103, 104 of two data tracks. Namely, the data (the audio signal of one channel) of one editing unit are allocated to one data track without being divided. The data of the other data tracks which are not shown in Fig. 10, are allocated onto the recording medium by the similar method. But in a record/reproducing apparatus of adopting a recording method, it is necessary to effect the tracing operation again with the head so as to renew (write one over another) only the portion on the recording medium to which the recording signal of a certain editing unit data is allocated when a certain editing unit data only is required to be edited from a plurality of editing unit data of the recording signals. But in the conventional recording method, as the data of one editing unit is allocated as it is to one data track without being divided, the linearity of the track may often be shifted due to the mechanical accuracy problem, and it is shifted especially if the recording apparatus is different from a reproducing apparatus. As a result, in the editing point, the interferences of the overlapped writing and the erasure remains are provided on both the sides of one track, generating the problem that the reproducing signals being considerably deteriorated. The reason will be described in detail hereinafter. Fig. 11 is a model chart showing how the reproduction signals are being deteriorated in the editing point to be caused when the linearity of the track has been shifted. Fig. 11 A shows a record pattern chart with the audio signals of four channels being recorded in the time series in accordance with the format shown in Fig. 10. The drawing 11 B is a record pattern chart in a case where the linearity of the track has been shifted by X1 in the track pitch direction with comparison with the record pattern shown in the drawing 11 A, with the insertion edition to the editing point (editing unit data "A2") about the editing unit data "A1" through "A4" of the audio signal of one channel of the audio signals of four channels shown in the drawing 11 A. The drawing 11 C is a record pattern chart with the linearity of the track being shifted by X2 in an inverse direction to the record pattern shown in the drawing 11 B as compared with the record pattern of the drawing 11 A, with the connecting record being performed from the editing unit data "A3" about the record pattern recorded as in the drawing 11 B. In Fig. 11 C, when the shift (X1) of the track shown in the drawing 11 B in the audio signal of one channel is opposite in direction in the shift (X2) direction of the track shown in the drawing 11 C, the majority of the editing unit data "C3" disappears due to the overlapped writing of the editing unit data "A2", "A3", thus deteriorating the reproduction signal of the editing unit data "C3" in the data track where the editing unit data "C3" has been allocated as shown in (1) portion. Likewise, even in the track where the editing unit data "A3" is allocated, the data "A3" of the prerecorded portion remains partially as the unerased remains, so that the reproduced signals of the newly recorded data "A3" (the portion of hatching) are to be deteriorated. Disclosure of the Invention: An object of the present invention is to provide a recording method and a recording apparatus for reducing the deterioration of the reproduction signals at the editing point as compared with the conventional recording method even when the editing operation is effected with the track being shifted from the already recorded track pattern because of the track linearity shift, the head height shift by the mechanical precision problems, further the tracking shift during the reproducing operation, and so on. In order to achieve the above object, a recording method is provided of allocating into a plurality of track portions in parallel tracks data signals to be recorded and composed of a plurality of editing units, each editing unit being the data of a minimum unit capable of rewriting operation, characterized by a step of dividing the data of the respective editing unit into N subunits, N being an integer of two or more, a step of dividing the track into a plurality of track portions in the longitudinal direction of the track, and a step of allocating the subunits of a respective editing unit into N track portions lying in pitch direction adjacent in N parallel tracks. Further, to achieve the above object, a recording apparatus is provided for allocating into a plurality of track positions in parallel tracks data signals to be recorded and composed of a plurality of editing units, each editing unit being the data of a minimum unit capable of rewriting operation characterized by a split means for dividing the data of the respective editing unit into N subunits, N being an integer of two or more, means for dividing the track into a plurality of track portions in the longitudinal direction of the track, and means for allocating the subunits of a respective editing unit into N track portions lying in pitch direction adjacent in N parallel tracks. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a format chart on the recording medium for the illustration of the recording method in a first embodiment of the present invention; Fig. 2 A through C is a module chart showing how the reproduction signals are deteriorated at the editing points to be caused when the linearity of the track has been shifted in the interchangeable reproduction by the recording method in the first embodiment of the present invention; Fig. 3 is a format chart on the recording medium for illustration of the recording method in a second embodiment of the present invention; Fig. 4 A through C are enlarged views with the circle interior of the (1) portion being enlarged; Fig. 5 is a block diagram of the recording apparatus of the present invention; Fig. 6 is a timing chart of the control signal to be outputted from a timing generating circuit 510 in Fig. 5; Fig. 7 is a block diagram showing the operating condition of a split circuit 506 of Fig. 5 in the periods of I, II, III, IV shown in Fig. 6; Fig. 8 is a timing chart showing the switching timings between the MUX531 and the MUX532 by the control signals to be outputted from the timing generating circuit 512 in Fig. 5; Fig. 9 is a timing chart showing the switching timings between the ASW533 and the ASW534 by the control signals to be outputted from the timing generating circuit 516 in Fig. 5; Fig. 10 is a format chart on the recording medium in the conventional recording method; Fig. 11 A through C are model charts showing how the reproduction signals are deteriorated at the edition point to be caused when the shifted linearity of the track has been shifted in the interchangeable reproduction by the format shown in Fig. 10. DESCRIPTION OF THE PREFERRED EMBODIMENT: The recording method in the embodiment of the present invention will be described hereinafter with reference to the drawings. Fig. 1 is a format chart on the recording medium recorded by the recoding method in the first embodiment of the present invention. Here, a case wherein one editing unit is supposed to be, for example, N = 2 in the dividing operation of one editing unit into N subunits (N is an integer of two or more) will be described. In the present embodiment, assume that the data of the "A1" through "D1" of four editing units are recorded, and the data "A1" through "D1" of the editing units are respectively divided into two (N=2) subunits "A11, A12" through "D11, D12", the respective data of the divided are allocated to the track portions "1" through "8" adjacent among the data tracks and are recorded on the recording medium. At this time, the region where the data of one editing unit is occupied in the recording medium is distributed narrowly in the head scanning direction and widely in the track pitch direction as compared with the conventional example. Also, the data of the editing unit in the other data track which are not shown in Fig. 1 is also allocated and recorded on the recording medium in the similar method. Fig. 2 A through C are model charts showing the deterioration of the reproduction signals at the editing point to be caused in a case when the linearity of the track has been shifted in the the interchangeable reproduction by the recording method in the first embodiment of the present invention. The drawing 2 A shows the record pattern chart recorded in accordance with the recording method in the first embodiment of the present invention, the inserting edition is effected up to the editing points ("A21, A22") about the "A11, A12", "A21, A22" through "A41, A42" within a plurality of editing unit data "A11, A12", "A21, A22" through "A41, A42", "B11, B12", "B21, B22" through "B41, B42", "C11, C12", "C21, C22" through "C41, C42", "D11, D12", "D21, D22" through "D41, d42" shown in the drawing 2 A, the drawing 2 B shows the recording pattern when the linearity of the track has been shifted by X1 in the track pitch direction through the comparison with the recording pattern shown in the drawing 2 A. The drawing 2 C is a record pattern chart when the linearity of the track has been inversely shifted by X2 to the record pattern shown in the same drawing B through comparison with the record pattern of the drawing 2 A, with the connection record being effected after the editing point in the record pattern recorded like the same drawing B, namely, in the "A31, A32" and "A41, A42". In Fig. 2 C, since a portion of the editing unit data "A22" disappears due to the overlapped writing due to the shift (X1) of the track shown in the drawing 2 B and the shift (X2) of the track shown in the drawing 2 C as shown in the (1) portion, the reproduction signal of the editing unit data "A22" is deteriorated. Here, through the comparison of the deterioration degree of the reproduction signal between a recording method in the first embodiment of the present invention by the format shown in Fig. 1 and the conventional recording method by the format shown in Fig. 10, in the comparison at one editing unit as clear from the data "C3" which is the (1) portion of Fig. 11 C, and the "A22" + "A21" which is the (1) portion of Fig. 2 C, it is found out that in the first embodiment of the present invention, the disappearance of the data due to the overlapped writing is less, and the degree of the deterioration of the reproduction signal is more improved than in the conventional embodiment. Namely, since the data of one editing unit is divided into two subunits and are allocated into two track portions adjacent between the data tracks, and are recorded, the subunits are necessarily recorded and reproduced by the recording and reproducing apparatus having the same editing unit data, so that there is no possibility of receiving the interferences of the overlapped writing and the unerased remains between two adjacent data tracks (for example, between the subunits "A11, A12" in Fig. 2 C) with one editing unit being divided and being allocated thereinto. Meanwhile, since the region occupied by one editing unit data is distributed so as to be narrow in the head scanning direction and wide in the track pitch direction as compared with the conventional arrangement, the region to be affected upon deterioration of the track linearity during exchanging reproduction is consequently reduced. Fig. 3 is a format on the recording medium recorded by the recording method in the second embodiment of the present invention. In the second embodiment, the audio signals of four channels which are, for example, M = 4, and the video signals are to be recorded as the audio signals of the M channels (M is a positive integer), and are allocated to five (4 : M + 1 = 5) partial data tracks. The data (not shown) of the editing unit of the audio signals of four channels and the video signals are inputted as the "A1", "A2" through "A6", the "B1", the "B2" through "B6", the "C1", the "C2" through "C6", the "D1", "D2" through "D6", the "V1", "V2" respectively in the time series order, and are to be recorded after having been divided. As in the first embodiment, the data of the editing unit of the audio signal of four channels are respectively divided into two subunits "A11, A12", the "A21, A22" through "A61, A62", the B11, B12", the "B21, B22" through the "B61, B62", the "C11, C12", the "C21, C22" through "C61, C62", the "D11, D12", the "D21, D22" through "D61, D62" as in the first embodiment, also, the editing unit data "V1", "V2" of the video signal are divided respectively into six subunits "V11, through V16", and "V21, through V26". In Fig. 3, each data of the audio signals of four channels are allocated, recorded onto the pairs (301, 302), (315, 316), (319, 320), (329, 330), (333, 324), (347, 348), and (303, 304), (313, 314), (317, 318), (331, 332), (335, 336), (345, 346), and (305, 306), (311, 312), (323, 324), (325, 326), (337, 338), (343, 344), and (307),308), (309, 310), (321, 322), (327, 328), (339, 340), (341, 342) of the adjacent two partial data tracks between the data tracks, and each data of the video signals are allocated, recorded onto the adjacent six partial data tracks (349 through 354) and (355 through 360) among the data tracks. Also, the example of the portion with the circle interior of the (1) portion of Fig. 3 being enlarged is shown in Fig. 4. In Fig. 4 A through C, there are shown patterns as to the way of arranging the track portions 339, 340 with the data "D51", "D52" with the data "D5" of one editing unit being divided being allocated thereto. In the region shown with broken lines in the drawing 4 A through 4 C, there is included only the data of one editing unit (in the same drawing, the editing unit data "D5"). As shown in the drawing 4 A through 4 C, there are many patterns as to the way of arranging the track portions with one editing unit of data being divided, allocated thereto, in which the data "D51", "D52" are completely adjacent as shown in, for example, the drawing 4 A, 4 B, and the data "D51", "D52" are somewhat shifted in the longitudinal direction of the track as shown in the drawing 4 C. But when the tracking shift has been caused in the editing operation of the data "C51", the influences of the tracking shifts are applied on the data "C52" adjacent to the data "C51", and the overlapped writing is effected on the data "D52" in such a pattern as shown in the drawing 4 C, so that the influence of the tracking shifts is higher than in the case of the drawing 4 A, B. Also, as shown in Fig. 3, although the present embodiment has, for example, one editing unit data "C5" divided into two subunits "C51", "C52" arranged in parallel contact into two tracks in the approximately vertical direction with respect to the head scanning direction, namely, the track pitch direction, the data "C5" may be divided into three as in the "C51", "C52", "C53" (not shown) and be brought into parallel contact with the three tracks. In this case, the length of the head scanning direction of each division data may be made shorter as compared with the case of the two division, also the length of the track pitch direction becomes longer as compared with the two divisions, so that the deterioration of the reproduction signals caused by the track shift is reduced. Namely, as the number of the divisions becomes larger, the deterioration of the reproduction signals may be reduced. In the present embodiment, although the data with the data of the editing unit of each signal is divided into subunits and, the subunits are recorded in the order of the audio signals of two channels, the video signal, the audio signals of two channels onto the five track portions per data track with one data track having five track portion divided in the longitudinal direction of the track, the order in which the respective subunits are allocated is not restricted to it. The data of the editing unit of each signal may be divided, and recorded so that the audio signals of four channels may be arranged continuously on the data track in the order of, for example, the audio signals of four channels, the video signal. Also, it is needless to say that the recording operation may be effected in the order of the video signal, and the audio signals of four channels. Further, the video signal can be divided into two so as to divide the data of the editing unit of each signal in the order of the video signal, the audio signal of four channels, and the video signal so that they may be allocated, recorded onto six track portions. Fig. 5 is a block diagram of the magnetic recording apparatus of the present invention, and the (1) through (11) are arranged to constitute one drawing with two. Referring to Fig. 5, reference numeral 501 is a means for dividing the data of the editing unit into N subunits, reference numeral 502 is a means for allocating the subunits to the track portions so as to record them on the recording medium. Reference numerals 504, 505, 514 are circuits for processing various types of signals, reference numerals 503, 506, 507, 508, 509 are split circuits, reference numerals 510, 512, 516 are timing generating circuits, reference numerals 511, 513 are change-over circuits, reference numeral 515 is a rotary transformer, reference numeral 517 is a cylinder, reference numerals 518, 519 and 520, 521 are a pair of heads, reference numerals 522 through 524 and reference numerals 529 through 532 are multiplexers (hereinafter referred to as MUX), reference numerals 525 through 528 are memories (hereinafter referred to as MEM), reference numerals 533, 534 are analog switches (hereinafter referred to as ASW), reference numerals 540 through 544 are input terminals. Although the data of the editing units of the audio signals of the four channels are inputted continuously in the time series order in the "A1", "A2", "A3", ..., the "B1", "B2", "B3", ..., the "C1", "C2", "C3", ..., the "D1", "D2", "D3", ... ..., the "A1", "B1", "C1", "D1" to be inputted at first will be described so as to shorten the description here. Also, by the repetition of the operation to be described hereinafter, it is possible to process the signals of all the data. The apparatus of the present embodiment is composed of a means 501 for dividing the data (audio signals of four channels) "A1", "B1", "C1", "D1" of the four editing units inputted through the signal processing circuit 504 for correcting the errors, and so on respectively into two subunits "A11", "A12", "B11" through "D11", "D12", and a means 502 for allocating them into a plurality of track portions lying in pitch direction adjacent in parallel tracks so as to record them on the magnetic recording medium. The operation thereof will be described hereinafter. The four editing units of data "A1", "B1" through "D1" inputted from the input terminals 540, 541, 542, 543 are inputted respectively into the split circuits 506 through 509 through the signal processing circuit 504. Each of the inputted data "A1", "B1" through "D1" are divided into the subunits "A11, A12", the "B11, B12" through "D11, D12" by the split circuits 506 through 509 with control signals to be obtained by the timing generating circuit 510 and are outputted into the change-over circuit 511. Also, the "V1" of the editing unit data of the video signals inputted from the input terminal 544 is inputted into the split circuit 503 through the signal processing circuit 504. In the split circuit 503, the inputted data "V1" is divided to output the "V11", "V12" as the output data. In the change-over circuit 511, the subunits "A11", "A12", "B11" through "D11", "D12" and "V11", "V12" are rearranged into the "A11", "B11", "V11", "C11", "D11" and "A12", "B12", "V12", "C12", "D12" in the time series order by the control signals to be obtained by the timing generating circuit 512 so as to output them respectively as the signals of CHO and CH1. The output signals CHO, CH1 outputted from the change-over circuit 511 are inputted into the change-over circuit 513 through the signal processing circuit 505 for effecting the digital/analog conversion and so on. The change-over circuit 513 is provided to record the signals CHO and CH1 on the recording medium bound on the cylinder 517 by the use of pair heads 518, 521 and pair heads 519, 520 mounted by 180 degrees in space on the cylinder 517. In the change-over circuit 513, the signals CHO and CH1 are outputted with the control signals to be obtained by the timing generating circuit 516 with the switching operation being effected after a certain period into the pair heads 518, 519 and the pair heads 521, 520. Each of four output signals outputted by the change-over circuit 513 is sent to each head 518, 519, 520, 521 through a signal processing circuit 514 and a rotary transfer 515. Also, the respective timing generating circuits 510, 512, 516 are adapted to output a control signal in accordance with an identifying signal (hereinafter referred as to ID signal) showing the type of the data to be outputted from the signal processing circuit 504 and the head switch (HSW). Fig. 6 shows a control signal to be outputted from a timing generating circuit 510 in Fig. 5. Fig. 6 shows a digital control signal of high or low, with the oblique line portions showing that the signal may be high or low. Table 1 shows the operation modes of the MUX522, 523, 524, 529, 530 which are used in the split circuit 506 in Fig. 5. Namely, when the control signals to be inputted is high, the respective MUXs are switched onto the terminal side of the (a), (c), (e), (g), (i), when the control signal is low, the respective MUXs are switched onto the terminal side of the (b), (d), (f), (h), (j). Table 2 shows the operation modes of the MEM525 through 528 which are used in the split circuit 506 in Fig. 5. Namely, when the control signal to be inputted is high, each MEM becomes a storing (write) mode, and when it becomes low, each MEM becomes a reading (read) mode. Fig. 7 shows the condition of the operations of the respective MEM525 through 528 and the MUX522, 523, 524, 529, 530 by the control signals T1 through T9 in the periods of I, II, III, IV shown in Fig. 6. Namely, when the MEM525, 526 are in the storing condition so as to continuously effect the signal processing operation, the MEM527, 528 are in the reading condition, and also, when the MEM525, 526 are in the reading condition, the MEM527, 528 are controlled to become the storing condition. The time series former half portion of one editing unit data "A1" of the inputted audio signal is controlled to be stored into the MEM525, MEM527, the time series latter half portion is controlled to be stored into the MEM 526, MEM528. Thus, it is found out from Fig. 10 that the inputted data "A1" of one editing unit is divided into the data of the "A11" and "A12" by the split circuit 506 according to the control signal to be obtained by the timing generating circuit 510, and is outputted into the change-over circuit 511. The split circuits 507, 508, 509 are also composed of MUX, MEM and so on as in the split circuit 506 to effect the similar operations. Namely, the data "B1", "C1", "D1" of the respective editing units inputted as in the split circuit 506 shown in Fig. 7 are divided into the data of the "B11" "B12", "C11" "C12", "D11" "12" by the split circuits 507, 508, 509 in accordance with the control signal to be obtained by the timing generating circuit 510, and are outputted into the change-over circuit 511. Table 3 shows the operation modes of the MUX531 and MUX532 in the change-over circuit 511 of Fig. 5. Namely, in the MUX531 and MUX532, the respective terminals of the (k), (p) are adapted to be selected when the control signals T10, T11 to be inputted are 0, the respective terminals of the (1), (q) are adapted to be selected when the control signals to be inputted are one, the respective terminals of the (m), (r) are adapted to be selected when they are two, the respective terminals of the (n), (s) are adapted to be selected when they are three, the respective terminals of the (o), (t) are selected when they are four. Fig. 8 shows the change-over operation of the MUX531 and MUX532 by the control signals T10, T11 and the control signals T10, T11 to be obtained by the timing generating circuit 512 of Fig. 6, and the output signals of the MUX531 and the MUX532 to be obtained by the change-over operation. Namely, the data divided by the change-over circuit 511 is arranged in the time series order in accordance with the control signals T10, T11 to be obtained by the timing generating circuit 512 and are outputted respectively as the signals CHO, CH1. Table 4 shows the operation modes of the ASW533 and ASW534 of the change-over circuit 513 of Fig. 5. In the ASW533 and ASW534, when the control signal to be inputted is high, the terminals of the (u) and (w) are selected respectively, and when the control signal to be inputted is low, the terminals of the (v) and (x) are selected respectively. Fig. 9 shows how the ASW533 and the ASW534 are changed over by the control signals T12, T13 and the control signals T12, T13 to be obtained by the timing generating circuit 516 of Fig. 5. In the change-over circuit 513, the signals CHO and CH1 are switched into the pair heads 518, 519 and the pair heads 521, 520 for each of the constant periods in accordance with the control signals T12, T13 to be obtained by the timing generating circuit 516, and may be outputted. The signals outputted from the change-over circuit 513 are fed respectively into the heads 518, 519, 520, 521 on the cylinder 517 through the signal processing circuit 514 for controlling the gain, the rotary transformer 515, and are recorded on the magnetic recording medium (not shown) by each head. Utilization Field in the Industry: Even when the editing operation is effected with the track being shifted from the track pattern already recorded on the recording medium because of the reasons of the linearity shifts of the tracks and the head height shifts, further the tracking shifts during the reproducing operation, and so on due to the mechanical precision problem as described in detail hereinabove, the deterioration of the reproduction signals at the edition points is to be improved as compared with the conventional recording method.

Claims: A recording method of allocating into a plurality of track portions of parallel tracks data signals to be recorded and composed of a plurality of editing units (A, B, C, D, ... V), each editing unit being the data of a minimum unit capable of rewriting operation, characterized by a step of dividing the data of the respective editing unit into N subunits (A₁₁, A₁₂, ... V₁₁, V₁₂, V₁₃, V₁₄, V₁₅, V₁₆), N being an integer of two or more, a step of dividing the track into a plurality of track portions (301, 303, 349, 305, 307) in the longitudinal direction of the track, and a step of allocating the subunits of a respective editing unit into N track portions lying in pitch direction adjacent in N parallel tracks. A recording method described in accordance with claim 1, wherein a step of dividing one editing unit of data into N subunits is to divide the data in the time series. A recording method described in accordance with claim 2, comprising the step of allocating into five track portions per data track, two first track portions being allocated to the audio signals of two channels (A, B), a further track portion being allocated to the video signal (V), and the last two track portions being allocated to the audio signals of two further channels (C, D). A recording method described in accordance with claim 2, comprising the step of allocating subunits into six track portions in the longitudinal direction, two portions being allocated to subunits of the video signal, and four portions being allocated to the audio signal of one of four channels respectively. A recording method described in accordance with claim 2, comprising the step of allocating the subunits (V₁₁-V₁₆) of the video signal into six track portions adjacent in pitch direction. A recording apparatus for allocating into a plurality of track positions in parallel tracks data signals to be recorded and composed of a plurality of editing units (A, B, C, D, V), each editing unit being the data of a minimum unit capable of rewriting operation characterized by a split means for dividing the data of the respective editing unit into N subunits (A₁₁, A₁₂ ... V₁₁, V₁₂, V₁₃, V₁₄, V₁₅, V₁₆), N being an integer of two or more, means for dividing the track into a plurality of track portions (301, 303, 349, 305, 307) in the longitudinal direction of the track, and means for allocating the subunits of a respective editing unit into N track portions lying in pitch direction adjacent in N parallel tracks.

Inventors: HOSOKAWA NOBUO, TOGASHI SHIGEKAZU, HOSOKAWA, NOBUO, TOGASHI, SHIGEKAZU
Applicants: MATSUSHITA ELECTRIC IND CO LTD, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Application year: 1989
Main classification: G11B20
IPC codes: G11B27, G11B20