1、STD-BSI BS EN b1595-2-ENGL 1997 W Lb24bb9 Ob57b84 750 W BRITISH STANDARD Multichannel digital audio tape recorder (DATR), reel-to-reel system, for professional use Part 1. Format A The European Standard EN 615951 : 1997 has the status of a British Standard ICs 33.160.30 NO COPYING WITHOUT BSI PERMIS
2、SION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 61595-1 : 1997 IEC 61595-1 : 1997 BS EN 61696-1 : 1997 under the authority of the effect on 16 October 1997 StandardsBoardandcomesinto Amd. No. Da 0 BSI 1997 IBN O 580 28426 5 National foreword Textaffected This British Standard is the English language
3、 version of EN 615951 : 1997. It is identical with IEC 615951 : 1997. The UK participation in its preparation was entrusted by Technical Committee EPUlOO, Audio, video and multimedia systems and equipment, to Subcommittee EPL“KV2, Recording, which has the responsibility to: - aid enquirers to unders
4、tand the text; - present to the responsible intemational/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; - monitor related intedonal and European developments and promulgate them in the UK. IEC 61595 will comprise the following par
5、ts: - Part 1: Format A - Part 2 Format B - Part 3 24 bit operation for 16 bit media A list of organizations represented on this subcommittee can be obtained on request toitsSC!CT 9 Allocation and dimension of magnetic tracks . 10 Assignment of magnetic tracks 11 Emphasis 12 Main track recording . 12
6、.1 Recording modulation method 12.2 Signal block structure . 12.2.1 The word format . 12.2.2 The frame and block structure 12.2.3 Synchronization pattern Signal word distribution to tracks 12.4 Error protection method . 3.1 12.3 12.4.1 The error correction code . 12.4.2 Interleave sequence . 12.5 Re
7、cording and reproducing characteristics . 12.5.1 Reference tape 13 Subtrack recording 13.1 Auxiliary channels 13.1.1 Time code channel (time code track) 13.1.3 Auxiliary analogue channels (cue audio-1 track and cue audio-2 track) . 13.2 Alignment of digital audio signals and subtrack signals . 13.2.
8、1 Alignment of cue audio-1 and cue audio-2 track signals 13.2.2 Alignment of time code track signals 13.1.2 Auxiliary data channel (auxiliary data track) Annex A . Bibliography Page 5 5 5 5 7 7 7 7 7 7 8 8 8 8 13 13 13 14 14 14 15 15 16 17 19 27 27 27 27 27 27 27 27 27 27 28 Q BSI 1997 STD-BSI BS EN
9、-bl595-l-ENGL 1997 lb24bb9 Ob57b89 232 Page 4 EN 61696-1 : 1997 1 8 3 4/6M conversion table . 14 4 Track interleave (20 main tracks with 12, 7 mm tape width) 23 5 Track interleave (40 main tracks with 12.7 mm tape width) 24 6 Track interleave (40 main tracks with 25.4 mm tape width) 25 7 Track inter
10、leave (80 main tracks with 25.4 mm tape width) 26 Tape width and number of digital audio channels . 2 Track assignment . 8 Figures 1 Recording channels of a DATR (digital audio tape recorder) 2 Data flow of the main audio channels of a DATR (digital audio tape recorder) 3 Reproducing channels of a D
11、ATR (digital audio tape recorder) 4 Track pattern for DATR on magnetic tape (24 tracks with 12, 7 mm tape width) 5 Track pattern for DATR on magnetic tape (47 tracks with 12, 7 mm tape width) 6 Track pattern for DATR on magnetic tape (45 tracks with 25, 4 mm tape width) 7 Track pattern for DATR on m
12、agnetic tape (89 tracks with 25, 4 mm tape width) 8 Emphasis characteristics . 9 Frame and block structure . 1 O Synchronization pattern . 11 Signal word distribution to tracks . 12 Symbol and word structure 13 Example of input data VI . 14 Main-frame interleave (tape speed I) . 15 Main-frame interl
13、eave (tape speed il) 16 Code interleave . 6 6 7 9 10 11 12 13 15 15 16 18 19 20 21 22 Annex ZA (normative) Normative references to international publications with their corresponding European publications 29 8 BSI 1997 STD-BSI BS EN b1595-1-ENGL 1797 1b24bb9 Ob57b90 T5V Page 6 EN 61696-1 : 1997 MULT
14、ICHANNEL DIGITAL AUDIO TAPE RECORDER (DATR), REEL-TO-REEL SYSTEM, FOR PROFESSIONAL USE - Part 1 : Format A 1 Scope This part of IEC 61595 applies to 8 to 64 channel digital audio recording on 12,7 mm or 25,4 mm wide tape (hereafter called tape), with stationary heads, for professional use. It define
15、s the mechanical and electrical characteristics necessary to ensure the interchangeability of programmes, recorded as digital audio signals on magnetic tape in professional industries. 2 Normative references The following normative documents contain provisions which, through reference in this text,
16、constitute provisions of this part of IEC 61595. At the time of publication, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on this part of IEC 61595 are encouraged to investigate the possibility of applying the most recent edition
17、s of the normative documents indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IEC 60461 : 1966, Time and control code for video tape recorders IEC 61 120-4: 1992, Digital audio tape recorder reel-to-reel system, using 6,3 mm magnetic tape, for pr
18、ofessional use - Pari 4: Magnetic tape properties: definitions and methods of measurement ITU-T V.41: 1988, Code-independent efror-control system - = - _. - II - * m * 3 Definition8 For the purpose of this part of IEC 61595, the following definitions apply. 3.1 Data flow of a digital audio tape reco
19、rder Figure 1 shows, within a block diagram, the main data flow of a DATR (digital audio tape recorder). Figure 2 shows the recording channels of a DATR. Figure 3 shows the reproducing channels of a DATR. STD-BSI BS EN b1575-1-ENGL 1777 W Lb24bbS Ob57bSL 790 0 DIA converter Analogueoutput - Page 6 E
20、N 61696-1 : 1997 4 Read head + amplifier - o D 0- amplier Digitai input Digital audio interiace 4 Digitai ouiput Time base Corrector . Tape 4 Demodulator . I Digital Digitaiaudi audio input interfece Digital O audio D o AID p-ing comreiter Anelogue audl0 input Modulator and write b Maintracks amplif
21、ier Figure 1 - Recording channels of a DATR (digital audio tape recorder) O Time code i input Figura 2 - Data flow of the main audio channels of a DATR (digital audio tape recorder) STD.&SI BS EN bL575-L-ENGLL777 Lb24bbS Ob57b72 827 D Demodulator Main tmcks b mad 4 aipiffier Page 7 EN 61696-1 : 1997
22、 Digitai audio bigitel audio Digitai -B interfaCa * output audio P-b 3 WA * Analogueaudio umverter output Auxilialy data +O output SUbtr&(S Tim unie output Time code channel demodulator Figure 3 - Reproducing channels of a DATR (digital audio tape recorder) 4 Digital encoding 4.1 Sampling frequency
23、The sampling frequency stall be 48 kHr, and the accuracy of the sampling frequency at encoding shall be f 50 x 10- . 4.2 Sampling timing It is recommended that all channels are sampled simultaneously. 4.3 Quantization Each audio sample shall be quantized uniformly and be expressed in 16 bits, 2s com
24、plement code. Positive numbers correspond to positive analogue voltages at the input. 5 Tapespeed The tape speed shall be nominal 76,20 cm/s (hereafter called speed I) and 38,lO cmis (hereafter called speed Il). The tolerance on tape speeds shall be within 0,2 o/. 6 Tape width and number of digital
25、audio channels O O The tape width shall be 25,374.03 mm (nominal 25,4 mm) or 12,66-0, mm (nominal 12,7 mm). Table 1 shows tape width and number of digital audio channels. STD-BSI BS EN bL595-1-ENGL 1997 m Lb2LibbS Ob57b93 7b3 Number of audio channels Main Number of tracks Sub Total Main trackslaudio
26、 channels Page 8 EN 61696-1 : 1997 64 80 9 89 1 018 Table 1 - Tap width and number of digital audio channels Tape width (mm) Main Digital audio Time code Items Contents I Track number 25,4 12,7 483 342 443 322 3 2 3 2 Tape width (mm) I 25.4 I 12.7 Tape speed Il 32 I 16 I 32 I 16 1018 1014 1018 1018
27、I I II I I I I 7 lape winding The magnetic coating faces the centre of the reel. 8 Reel and hub Under consideration. 9 Allocation and dimension of magnetic track8 The figures 4, 5, 6 and 7 show the track allocations on magnetic tape. 10 Assignment of magnetic tracks If the tape moves from the left t
28、o right with the magnetic coating facing away from the observer and with the leader to the right, the bottom track is designated track 1, the next upper track is designated track 2 and so on. Table 2 shows the assignment of magnetic tracks. Table 2 - Track assignment I Typeoftrack I I Cue audio-1 I
29、85 I 43 11111 I I I I I l I I 24 I Sub Cueaudio-2 87 44 47 I I Auxiliary data I 12y*86 88 89 I 1,45 12.44,45.461 23 I STD-BSI-BS EN b1595-1-ENGL 1797 Lb2Libb7 Ob57b94 bTT Page 9 EN 61696-1 : 1997 Track 24 Track 22 / nt I I u t E O Cu .- EC 4m7 o- I Figure 4 - Track pattern for DATR on magnetic tape
30、(24 tracks with 12,7 mm tape width) STD-BSI BS EN b1595-1-ENGL 1777 m 1bZllbbS Ob57b75 53b Page 10 EN 61696-1 : 1997 I I SI IEC 471m Figure 5 - Track pattern for DATR on magnetic tape (47 track8 with 12,7 mm tape width) STD-BSI BS EN bL595-L-ENGL 1997 m Lb2Libb9 Ob57b9b 472 m Page 11 EN 61696-1 : 19
31、97 h Track 4 I I IEC 47w7 Figure 6 - Track pattern for DATR on magnetic tape (45 tracks with 25,4 mm tape width) , Page12 EN 61696-1 : 1997 Track 89 t Track 82 Track 81 Y I Y Track li I Track 10 Track 9 i Figure 7 - Track pattern for DATR on magnetic tape (89 tracks with 25,4 mm tape wldth) * rn * S
32、TD.BSI BS EN bL595-L-ENGL 1997 1b24bbS Ob57b78 245 Page 13 EN 61696-1 : 1997 11 Emphasis In general, the use of emphasis is not recommended. If pre-emphasis is applied, the emphasis shall be used with the characteristics of a first order pre-emphasis, as shown in figure 8. B p. +lo +5 Pre-emphasis +
33、6d0loct -6dB/ocl - “1 -51 De-emphasis -I .1 k 2k 4k 8k 2k Frequency (Hz) Kc 474Q7 Figure 8 - Emphasis characteristics 12 Main track recording 1 2.1 Recording modulation method In this subclause, the method is first defined to convert a binary data sequence of each of the main digital tracks for reco
34、rding on the magnetic tape. The second item, described in 12.2.3, is the definition of the synchronization pattern in recording code. The converted code is given by NRZI. The 4/6M system shall be used as recording modulation method. The 4/6M system is defined by dividing a binary data sequence into
35、4-bit or 6-bit data segments and converting these into six-cell or nine-cell codes respectively. This system ensures no less than one and no more than six code cells “O“ exist between any code cells “1“ in a sequence of converted code. The conversion rule is given by table 3. Page 14 EN 61595-1 : 19
36、97 Original data bits Converted code cells Table 3 - 4BY conversion table Original data bits Converted code cells woo O001 O0 O001 O1 000110 _ o1 woo o1 O0 o1 O01 o xooo1 O001 O101 xoo1 O0 010100 x00100001 o1 10 x01000001 o111 xo1 O00 I 0001 11 I x01010001 I 1000 I xo1001 I O01 O00 001001 O01 o1 o O
37、01 o1 1 010000001 1 O01 010001 010010001 1010 xooo1 o 010100001 101 1 xo1 O1 o x00010000 1100 xooooo I O01 1 O0 I x01010000 I 1101 I xoooo1 I 001110 001111 I 001101 I O1 O01 O000 I 1110 I xoo101 I x00100000 1111 010101 o1 O1 00000 - - where X is complement logic of the code cell immediately before c
38、ode bit X in the converted code sequence. 12.2 Signal block structure 12.2.1 The word format The word slots have 16 bits, and MSB leading shall be used. 12.2.2 The frame and block structure 1) Frame and block structure Figure 9 shows the frame and block structure. STD-BSI BS EN bL595-L-ENGL 1997 Lb2
39、qbbS 0b57700 723 9 SYNCB SYNCC Page 16 EN 61696-1 : 1997 0101 O01 01010001 O10001 o 1 o o 1 o 1 o o o 1 o o o 1 o o 1 o o 1 Frame configuration - 1-f-I Maintrack I I SYNC I Digitalaudiodata I C1 (CRC) I II I I igitai audio data C1 (CRC) igitai audio data C1 (CRC) Digitai audio data Ci (CRC) II I Ib
40、I SYNC Dighi audio data C1 (CRC) = - (Pl Ci (CRC) Block configuration Figure 9 - Frame and block structure - SYNC length II _. * * rn x- 1 x-2 x-3 x-4 x-5 X-6 x-7 X-8 x-Q x- 10 a ._ - = - 2) Frame and block parameters - - Digital audio data or C2 length - Cl(CRC) length - Frame length - Block config
41、uration IEC 47m p = 16 bits d = 192 bits c = 16 bits f = 224 bits b = 10 frames 12.2.3 Synchronization pattern The synchronization pattern in recording code consists of 21 cells. The synchronization pattern is represented in NRZI, and given as follows. I SYNCA 10 1 O O 1 O O O 10-1 O O 1 O 0 1 O 07
42、12.3 Signal word distribution to tracks Incoming digital audio samples of eight audio channels (in case of tape speed I) or four audio channels (in case of tape speed Il) are allocated to eight tracks and two additional tracks of CP-check data are encoded as described in figure 11. STDTBSI BS EN b15
43、95-1-ENGL 1997 = lb2Libb9 Ob57701 bbT Page 16 EN 61696-1 : 1997 1) Tapespeedl Audio channels Main track 1 x- 1 2 x-2 3 x-3 4 x-4 5 x-5 6 X-6 7 x-7 8 X-8 C2 check (P) x-9 - (QI x- 10 IEC rnm 2 Tape speed II Audio channels Main track x-1 x-5 x-2 X-6 x-3 x-7 x-4 x-8 1 2 3 4 Figure 11 - Signal word dist
44、ribution to tracks 12.4 Error protection method The error protection method is two-dimensional. Error detection is made possible by the CRC check word recorded for each frame on each track, and by the Reed-Solomon code. Error correction is made possible by the Reed-Solomon code with the aid of CRC c
45、heck results. STD-BSI BS EN b1595-1-ENGL 1997 lb24b69 b57702 5Tb II Page 17 EN 61696-1 : 1997 12.4.1 The error correction code The error correction code referred to as the RSC code shall be used. The RSC code is a subclass of the generalized product code. The code is constructed by the (10, 8, 3) Re
46、ed-Solomon code over the Galois Field GF(24), as code C2, and by the (208, 192, 4) CRC over Galois Field GF(2), as code C1. Generator polynomial for code C1 is given by the following equation: G(X) = X* + X2+ x5 + G(X) is the generator polynomial based on the ITU-T V.41 recommended 16-bit Cyclic Red
47、undancy Check (CRC) word. The initial condition of all ones shall be used in generating the check bits, with the MSB transmitted first. a is the primitive element of GF(Z4). The vector representation of a is: a=(O O 1 O) a3 a2 a1 ao and the primitive polynomial 9(x) is given by the following equatio
48、n: g(x) = fi + x+ 1 The elements al to a0 are shown as follows. aJa2aaO al = (1 1 1 1) * * vi a2= (1 1 1 O) a3= (1 1 O 1) a4= (1 1 O O) a5= (1 O 1 1) a7= (1 O O 1) +=(i o 1 O) ae= (1 o o O) 1) C2encoder The C2 check code shall be calculated so as to meet the following equation: where V2 is encoded d
49、ata consisting of the input data stream and C2 check symbols, and H2 is the parity check matrix which shall be given as follows: I 11 11 111 al a2 a3 a4 a5 aG rt7 a0 1 0 H* = _ STD.BS1 BS EN bL595-1-ENGL 1997 Lb2LibbS Lib57703 432 D Digital audio data 1 ward Page 18 EN 61696-1 : 1997 MSB LSB 1514131211109 8 7 6 5 4 3 2 1 O The example of the encoded data V2 is shown as follows: v2 = Input data symbols C2 check symbols lstsvmbol I 3 2 1 O I 2nd symbol 13 2 i 01 3rd symbol 13 2 i 01 4th symbol 13 2 i 01 Record
