1、SMPTE 277M b 8357403 0002376 731 M SMPTE STANDARD ANSVSMPTE 277M-1996 for Television Digital Recording - 19-mm Type D-6 - Helical Data, Longitudinal Index, Cue and Control Records 1 Scope 1.1 This standard specifies the format and recording method of the data blocks and asso- ciated data which form
2、the helical records on 19-mm tape in cassettes as specified in SMPTE 226M. The data recorded may be digital video and audio data of various image standards up to approximately 1 Gbit/s as specied in ANSVSMPTE 278M. 1.2 Also specified are the content, format, and recording method of the longitudinal
3、record con- taining tracking information for the scanning heads associated with the helical records, and the longitudinal index and cue tracks. 1.3 In addition, this standard specifies the prin- cipal properties of the magnetic tape used for 19-mm type D-6 digital recording. 2 Normative reference Th
4、e following standard contains provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate t
5、he possibility of applying the most recent edition of the standard indicated below. ANSVSMPTE 278M-1996, Television Digital Recording - 19-mm Type D-6 - Content of Helical Data and Time and Control Code Records 3 Measurement environment 3.1 Dimensions are in the metric system. Page 1 of 22 pages 3.2
6、 Tests and measurements made on the system to check the requirements of this standard shall be carried out under the following conditions: - Temperature: 20C k 1C - Relative humidity: (50 2)% - Barometric pressure: 96 kPa f 1 O kPa - Tape conditioning: Not less than 24 hours - Center span tension: 0
7、.65 N 0.05 N 4 Tape specification 4.1 Base The base material shall be polyester or equivalent. 4.2 Width The tape width shall be 19.010 mm I 0.015 mm. 4.2.1 The tape, covered with a glass plate, shall be measured without tension at a minimum of five different positions along the tape using a calibra
8、ted microscope or profile projector having an accuracy of at least 1.0 pm. Tape width is defined as the average of the five readi ngs. 4.3 Width fluctuation Width fluctuation shall not exceed 6 pm p-p. 4.3.1 Measurement of width fluctuation shall be over a tape length of 900 mm at least 1 m from the
9、 beginning of the tape. The width fluc- tuation shall be evaluated by measuring the tape width at 10 points, each separated by a distance of 100 mm. CAUTION NOTICE: This Standard may be revised or withdrawn at any lime. The procedures of the Standard Developer require that action be taken to reaffir
10、m, revise, or withdraw this standard no later than five years from the date of publication. Purchasers of standards may receive current information on all standards by calling or r writing the Standard Developer. Printed in USA. 595 W. Hartsdaie Ave., White Plains, NY 10607 (914) 761-1100 Approved J
11、une 6,1996 SMPTE 27711 96 ANSVSMPTE 277M-1996 4.4 Reference edge straightness The reference edge straightness maximum deviation is 6 pm p-p. 4.4.1 Edge straightness fluctuation is measured at the edge of a moving tape guided by three guides having contact with the same reference edge and having a di
12、stance of 125 mm from the first to the second guide, and 125 mm from the second to the third guide. Edge measure- ments are averaged over 1 O-mm lengths and are made near the midpoint between the first and second guide which is 62.5 mm from the first guide. 8357403 0002377 878 yield strength. The in
13、itial tangential slope is extended and read at 1% elongation. 4.8 Magnetic coating The magnetic tape used shall have a metal particle coating or equivalent. 4.8.1 The coating coercivity shall be a class 1700 Oe (135300 Ah), as measured by a VSM or a 50/60-Hz BH meter. 4.8.2 The metal particles shall
14、 be longitudinally oriented. 5 Track arrangements 4.5 Tape thickness 5.1 Definitions The magnetic tape used shall have a thickness of 11 ym + O ym-0.8 pm. 4.6 Transmissivity Transmissivity shall be less than 5%, measured over the range of wavelengths 700 nm to 900 nm. 4.7 Offset yield strength Offse
15、t yield strength shall be greater than 14 N. 4.7.1 The force to produce 1% elongation of a 200-mm test sample with a pull rate of 100 mm per minute shall be used to confirm the offset 5.1.1 block: A packet of data including the preceding synchronization and identification information. All blocks of
16、one recording configu- ration have the same number of bytes. 5.1.2 cluster: An array of eight adjacent tracks (see figure 1). The numbering of the clusters starts with cluster O at the program reference point. 5.1.3 datafield: A group of segments which starts with cluster O as defined by the program
17、 reference point (see figure 1). Up to four data fields (O . 3) may be defined. The start of even- numbered data fields coincides with the two data field pulse as defined in 9.2.8. Direction of Tape Travel I I Cluster O 8 Tracks = 1 Cluster - Figure 1 - Cluster of tracks l! Page 2 of 22 pages SMPTE
18、27711 76 8357403 0002378 704 m 5.1.4 sector: Part of a cluster created by parti- tioning of all eight tracks in the same way (see figures 2 and 3). Each part of a partitioned track will start with a preamble and end with a post- amble. 5.1.5 segment: A group of sectors. The format allows a segment t
19、o contain sectors of different clusters. Two possible examples are shown in figures 2 and 3. 5.1.6 track: A track contains 270 blocks. Blocks within a track are numbered 1 through 270 in the direction of recording. The first block is a preamble and the 270th block is a postamble. Tracks are numbered
20、 O to 7 as shown in figure I. 5.2 Data configurations All recorded blocks along a slant track have the same size in order to record a data pattern independent of any video-, audio-, and edit-gap parts of the track. The total number of bytes per block depends on the recording configuration. For a giv
21、en configuration, all blocks contain the same number of bytes. Two con- figurations are allowed: - Configuration I: Total block length = 229 bytes; - Configuration II: Total block length = 239 bytes. All blocks consist of data preceded by a synchroniza- tion pattern, SYNC (see figure 4). Sync is not
22、 subject C-Sectors 3- Sectors A-Sectors SegmenK O Segment 2 - start of Data Field- Figure 2 - Segment and sector counting (Example a) ANSIISMPTE 277M-1996 to channel modification and is 24 bits on tape. This is equivalent to the length of two data bytes before channel modulation. The 24-bit sync pat
23、tern may be unique and not contained in the modulation tables given in clause 11. The task of the sync is to synchronize the channel decoder and to control word and block synchronization. The sync depends on the recorded data or video standard. Two types of data are used: inner code blocks and pream
24、bles/ postambles. The inner code blocks contain the RData bytes and the preceding block identification (ID), both protected by check bytes (see figure 5). For details of the error protection, see ANSVSMPTE 278M. The preambles/postambles contain a runup pat- tern of 224 (234) bytes of CC(hex) precede
25、d by a block identification (ID) (see figures 6 and 7). Preambles/postambles are of sufficient length to make additional edit gaps unnecessary. Preambles and postambles may be altered on tape by editing within a cluster without any negative effects. The identification (ID) bytes within each block co
26、ntain the block-, track-, segment-, and field-numbering, as well as some bits to identify the recorded data orvideo standards (see figure 8). Each block has a three-byte ID (ID O, ID 1, ID 2) which will also be protected by the check bytes. ID O is recorded first. C-Sectors . B-Sectors A-Sectors . .
27、 Segment Segment 3 - start of Data Field Figure 3 - Segment and sector counting (Example b) Page 3 of 22 pages SMPTE 27711 b H 357403 0002379 b1iO ANSUSMPTE 277M-1996 SYNC I Data I bytes I 227 bytes for configuration I 237 bytes for configuration II Figure 4 - Block structure in bytes Inner Code Blo
28、ck Figure 5 - Structure, in bytes, of the inner code block before channel modulation O 1 2 3 4 5 6 7 01 11 11 01 01 11 Figure 6 - One byte of run-up pattern before channel modulation SY bytes bytes 213 224/234 bytes I Preamble/postarnble (length = 227/237 bytes) 1 byte - Figure 7 - Structure, in byt
29、es, of preamble/postamble before channel modulation Page 4 of 22 pages SMPTE 27711 96 8357403 0002380 362 = ANSIISMPTE 2“M-1996 LSB MSB O 1 2 3 4 5 6 7 ID O: TO I T1 I T2 I so I s1 I s2 I FO I F1 O 1 2 3 4 5 6 7 ID 1: BO I Bl I B2 I 83 I 84 I 85 I B6 I B7 O 1 2 3 4 5 6 7 ID 2: B8 I QO I Q1 1 Q2 I Q3
30、 I Q4 I Q5 I Q6 Figure 8 - ID information The three ID bytes are defined as follows: The randomization shall be performed by an exclusive-or (X-OR) operation of the data bytes and associated outer check bytes with the randomizing bytes commencing with the first byte location after the identification
31、 (ID) bytes. The result of the ex-oring are ID O: TO . T2: Track identification (O . 7) SO . S2: FO, F1: Segment identification (O . 7) Data field identification (O . 3) ID 1 : 60 .,. B7: Block identification (eight bits) the RData bytes. ID 2: B8: Block identification (ninth bit) dependent QO . Q6:
32、 Data or video standard 6 Randomization All data bytes and associated outer check bytes (see for example figure 11 of ANSI/SMPTE 278M) shall be randomized before being inserted into the inner code block and before calculation of the inner check bytes. Sync, IDS, inner check bytes, and the run-up pat
33、terns A randomizing sequence is formed by reading succes- sive bytes from table 1. The sequence may commence at any address location in the table between OOOh and FOEh and continue sequentially for 208/218 bytes. The starting address of the randomizing sequence is defined by the ID words. The exact
34、relation between starting address and ID words depends on the of the preamble and postamble are not randomized, recorded video or data standard. Table 1 - Randomization sequence O0 10 20 30 40 50 60 70 80 90 AO BO CO DO EO FO O FF 61 7F BO 3F D8 1F 6C OF 36 87 1B 43 8D Al C6 1 DO E3 E8 F1 F4 78 7A 3
35、c 3D 9E 1E CF 8F E7 c7 73 2 63 39 81 9c 58 CE 2c 67 16 33 OB 19 05 8C 02 46 3 o1 A3 80 D1 40 68 20 B4 10 5A 88 2D c4 96 E2 4B 4 71 25 38 12 1c 89 8E 44 47 A2 23 51 91 28 48 94 5 A4 4A D2 A5 E9 52 74 A9 3A 54 1D 2A OE 95 07 CA 6 03 E5 81 72 CO B9 60 DC 30 EE 98 77 4c BB 26 DD 7 93 6E 49 37 24 9B 92 C
36、D c9 E6 64 F3 82 79 D9 BC - 89 EC 04 DE 2F 76 82 EF 97 38 41 F7 CB 90 AO FB 65 4E 50 FD 32 27 A8 7E 99 13 D4 BF CC O9 6A 5F 66 _- ABC B5 35 OD 83 62 70 DA 9A 86 59 31 88 6D 4D C3 AC 18 5C B6 A6 El 56 OC AE 5B D3 FO 2B 06 57 AD 69 F8 15 83 AB D6 34 7C 8A C1 55 6B 1A BE C5 EO AA D DF D5 6F EA 87 F5 DB
37、 FA ED 7D F6 3E 78 9F BD 4F E 5E A7 AF 53 D7 29 EB 14 75 OA BA 85 5D 42 2E 21 F 17 90 8B C8 45 E4 22 F2 11 F9 08 FC 84 FE c2 - Page 5 of 22 pages SMPTE 277M 96 D 8357q03 0002383 2T D ANSVSMPTE 277M-1996 Modulation table AI 1 1 O 7 Modulation code 9.2.1 Method of recording The blocks are subject to a
38、n 8-12 modulation coding prior to recording. Eight tables are used to map incom- ing data bytes to 12-bit words. The tables given in this standard are not valid for the sync which may be a unique sequence as described in ANSVSMPTE 278M. The modulation tables are numbered Al to A4 and B1 to 84. The t
39、able used depends on parameters Pa, Pb, Pc (see table 2). Modulation table A2 1 1 1 Modulation table A3 1 O O Modulation table A4 1 O 1 Modulation table B1 O 1 O For the preset byte of data: The control track shall be recorded using the direct saturated (nonbiased) recording method. Pa is true (“I“)
40、 a) if no * is attached in the modula- tion table to the previous data, OR b) if the pre- vious modulation bits are pari of a sync. Pb is true (“1“) if the last bit of the previous modu- lation bits of data or sync equals “O.“ Pc is true (“1“) a) if the next modulation bits are not pari of a sync, A
41、ND b) the first two bits of the next byte of data prior to modulation equal “1 O“ (first bit written left). Table 2 - Selection of modulation tables 8.2 Record equalization The record head current should generate the same flux levels at the head gap at both the Nyquist and half-Nyquist frequencies.
42、8.3 Record level Record head current should be optimized for best reproduced signal-to-noise ratio at the highest con- stant recorded frequency (i.e., the Nyquist frequency of the channel). Other methods of setting the record level are permitted, providing they achieve equivalent recuits. 9 Longitud
43、inal tracks 9.1 General There are three longitudinal tracks as dimensionally specified in clause 10. These tracks carry the index, cue, and control records. This clause describes their electrical parameters. 9.2 Control track Modulation table B2 I Modulation table 83 1 9.2.2 Servo reference pulse do
44、ublet O 1 O O O 1 Modulation table B4 O O IJ The servo reference pulse at the time of recording shall be a series of pulse doublets with a pulse distance of 3.33 ms as shown in figure 9. For the modulation tables, see clause 11. Recording starts with the left modulation bit leading. The unmodulated
45、data are given in hexadecimal form with 9.2.3 Flux polarity the left digit representing the four most significant bits of the byte of unmodulated data. During the time interval A (see figure 9) of the record, the polarity of the recorded flux shall be such that the 8 Magnetization south poles of the
46、 magnetic domains point in the direction of normal tape movement. During time B, the north poles shall be similarly oriented. 8.1 Polarity The recorder shall operate in reproduce mode without regard to the polarity of the recorded flux on the helical tracks. signal. 9.2.4 Flux level The recorded cur
47、rent shall maximize the playback Page 6 of 22 pages SMPTE 277M 96 = 8357401 0002382 135 M ANSUSMPTE 277M-1996 kPuiseDistance4 4T I $ 33ms /1 Av A$ - EDITArea % Servo Ref. Two Data Field Pulse 7 T ?- Sequence Start Pulse Servo Ref. I Servo Pulse doublet detail /Reference Point Notes: T =- 104ps Refer
48、ence Puise Rise time 15ps 1L - Figure 9 - Control track waveform timing 9.2.5 Pulse doublet width The recorded pulse doublets shall each have a half width T of 104 p nominal. The rise and fall times of the record current (1 0% to 90% points) shall be less than 15 ps and differ by less than 5 ps. Tha
49、t servo reference pulse doublet coincides with the program reference point (see figure 1 O). 9.2.9 EDIT timing Any edit point shall take place in the unmagnetized space between pulse groups. 9.2.6 Servo reference pulse doublet timing 9.3 Cue record The servo reference pulse doublet and the data of the program reference point when recorded shall occur at the same time (see dimension P1 in table 3). 9.2.7 Sequence start pulse A second pulse doublet shall, when present, indicate located at a distance of 4T after the servo reference pulse doublet. 9.2.8
