1、BRITISH STANDARD BSEN 61120-3:1994 IEC1120-3: 1991 Digital audio tape recorder reel to reel system, using6.3mm magnetic tape, for professional use Part 3: Format B The EuropeanStandard EN61120-3:1993 has the status of a BritishStandard UDC621.396.7:681.84.083.84:681.327.636BSEN 61120-3:1994 This Bri
2、tishStandard, having been prepared under the directionof the Electronic Equipment Standards Policy Committee, was published underthe authority of the Standards Board and comesintoeffect on 15January1994 BSI01-2000 The following BSI references relate to the work on this standard: Committee referenceE
3、EL/22 Draft for comment89/22505DC ISBN 0 580 22696 4 Cooperating organizations The European Committee for Electrotechnical Standardization (CENELEC), under whose supervision this EuropeanStandard was prepared, comprises the national committees of the following countries: Austria Italy Belgium Luxemb
4、ourg Denmark Netherlands Finland Norway France Portugal Germany Spain Greece Sweden Iceland Switzerland Ireland United Kingdom Amendments issued since publication Amd. No. Date CommentsBSEN 61120-3:1994 BSI 01-2000 i Contents Page Cooperating organizations Inside front cover National foreword ii For
5、eword 2 Text of EN61120-3 3 National annex NA (informative) Committees responsible Inside back cover National annex NB (informative) Cross-references Inside back coverBSEN 61120-3:1994 ii BSI 01-2000 National foreword This BritishStandard has been prepared under the direction of the Electronic Equip
6、ment Standards Policy Committee and is the English language version of EN61120-3:1993 Digital audio tape recorder reel to reel system, using6,3mm magnetic tape, for professional use, Part3: Format B, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical
7、with IEC1120-3:1991, published by the InternationalElectrotechnicalCommission (IEC). BSEN61120 consists of the following Parts. Part 1: General requirements; Part 2: Format A; Part 3: Format B; Part 4: Magnetic tape properties: definitions and methods of measurement; Part 5: Reels for6.3mm digital a
8、udio tape 1) . Additional information. IEC1120-4 stated in1.5.1 and1.5.3 as being “(under consideration)” was published in1992, and was implemented as BSEN61120-4:1993. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsib
9、le for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, the EN title page, pages2 to18, an inside back cover and a back cover. This sta
10、ndard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) In preparation.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN61120-3 October1993 UDC621.396.7:681.84.083.84:681.327.636 Descriptors:
11、 Audio recording, digital recording, magnetic tape, code, format, recording characteristics, recording track English version Digital audio tape recorder reel to reel system, using6,3mm magnetic tape, for professional use Part3: Format B (IEC1120-3:1991) Systme denregistrement bande audionumrique, bo
12、bine bobine, utilisant une bande magntique de6,3mm, usage professionnel Partie3: FormatB (CEI1120-3:1991) Digitales Tonbandgert Spulensystem mit Magnetband6,3mm fr Studioanwendungen Teil3: FormatB (IEC1120-3:1991) This EuropeanStandard was approved by CENELEC on1993-09-22. CENELEC members are bound
13、to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Centr
14、al Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same sta
15、tus as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for
16、 Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1993 Copyright reserved to CENELEC members Ref.No.EN61120-3:1993EEN 61120-3:1993 BSI 01-2000 2 Foreword The CENE
17、LEC questionnaire procedure, performed for finding out whether or not the InternationalStandard IEC1120-3:1991 could be accepted without textual changes, has shown that no common modifications were necessary for the acceptance as EuropeanStandard. The reference document was submitted to the CENELEC
18、members for formal vote and was approved by CENELEC as EN61120-3 on22September1993. The following dates were fixed: For products which have complied with the relevant national standard before1994-09-01, as shown by the manufacturer or by a certification body, this previous standard may continue to a
19、pply for production until1999-09-01. Annexes designated “normative” are part of the body of the standard. In this standard, Annex ZA is normative. Contents Page Foreword 2 1 Main track recording 3 1.1 Recording modulation method 3 1.2 Signal block structure 5 1.2.1 The word format 5 1.2.2 The block
20、structure 5 1.2.3 The Sync/Control word 7 1.3 Signal word distribution to tracks 8 1.3.1 Track-to-channel assignment 8 1.3.2 Signal word distribution to tracks 9 1.4 Error protection method 10 1.4.1 Interleaving and parity sums 10 1.4.2 The CRC word 12 1.5 Recording and reproducing characteristics 1
21、2 1.5.1 Reference tape 12 1.5.2 Calibration tapes 13 1.5.3 Procedure for adjusting recording current level and waveform 13 1.5.4 Specifications of tolerance relative to calibration tape 13 Page 2 Sub-track recording 13 2.1 Digital recording method 13 2.1.1 Recording method on sub-track2 13 2.1.1.1 T
22、he recording code 13 2.1.1.2 The data format 14 2.1.1.3 The synchronization pattern 14 2.1.1.4 The Control word 15 2.1.1.5 The Reference address 15 2.1.1.6 The CRC word 16 2.2 Alignment of digital audio signals and sub-track signals 16 2.2.1 Alignment of cue audio-1 and cue audio-2 track signals 16
23、2.2.2 Alignment of time code track signal 16 2.2.3 Alignment of Reference track signal 16 Annex ZA (normative) Other international publications quoted in this standard with the references of the relevant European publications 17 Figure 1 Computation ofP andQ check words 10 Figure 2 Analytical expres
24、sion for computingP andQ check words 10 Figure 3 Contents of one block, referred to one track input sequence 11 Figure 4 Contents of one block for all tracks, referred to one audio channel input 11 Figure 5 Contents of4 simultaneous blocks from one audio channel 12 Figure 6 Contents of the Sync/Cont
25、rol word in each block 12 latest date of publication ofan identical national standard (dop)1994-09-01 latest date of withdrawal ofconflicting national standards (dow)1994-09-01EN 61120-3:1993 BSI 01-2000 3 Electrical requirements for recording and reproducing equipment. 1 Main track recording 1.1 Re
26、cording modulation method In this subclause the modulation of a binary data sequence (“incoming data”) into a record signal waveform (“output wave form”) is specified. Next, a synchronization pattern violating the modulation rules is defined. The data to be recorded onto the main tracks are first ch
27、annel-coded. A non-D.C.-free, run-length-limited code called HDM-1 is used. The output waveform is defined by two cells for each input data bit. Only transitions in the output waveform are defined; the output waveform is polarity-free. Rules for generating a pair of output waveform cells for each in
28、put bit are defined in the following formulation and bit to waveform transitions are defined in rules1 and2. * Formulation for bit to waveform modulation. * Rule1 (center transitions): A data bit sequence of “01” always leads to a center transition in the middle of the “1”bit. Thus, the presence in
29、the data bit sequence of a bit pattern “01” always enforces a center transition in the cell sequence. Rule1 in HDM-1 encoding: Center transitions Data bit sequence Transition sequence of HDM-1 cells caused by “01” bit sequence: Resulting HDM-1 cells waveform: Alternate HDM-1 cells waveform:EN 61120-
30、3:1993 4 BSI 01-2000 * Rule2 (edge transitions): Under the three conditions defined and illustrated below and relating to specified bit sequences together with the absence of edge or center transitions in the HDM-1-coded sequence as indicated by the symbol(*) an edge transition is imposed in the cel
31、l sequence. In all other cases, no transition is generated. Case 1: Data bit sequence “10”, no transitions in the cell sequence at the positions indicated by (*): Case 2: Every data sequence “111”, no transitions in the cell sequence at the positions indicated by (*): Data bit sequence Transition se
32、quence of HDM-1 cells caused by “10” bit sequence in the absence transitions at (*): Resulting HDM-1 cells waveform: Alternate HDM-1 cell waveform: Data bit sequence Transition sequence of HDM-1 caused by“111” bit sequence in the absence of transitions at (*): Resulting HDM-1 cells waveform: Alterna
33、te HDM-1 cells waveform:EN 61120-3:1993 BSI 01-2000 5 Case 3: Data sequence “0000”, no transitions in the cell sequence at the positions indicated by (*): As a consequence of the rules of HDM-1 encoding, the minimum distance between transitions in a HDM-1 signal is3 cells. The maximum distance is9ce
34、lls, and two consecutive transition distances cannot be both equal to9cells. This makes it possible to use two consecutive run lengths of9 cells as a synchronization pattern which violates the rules of HDM-1. 1.2 Signal block structure 1.2.1 The word format A word length of16bits and uniform quantiz
35、ation with twos complement and MSB leading shall be used. 1.2.2 The block structure The data on the main tracks are formatted into blocks, each block consisting of18 words of16bits. The first word in a block is called the Sync/Control word, and is described in1.2.3. The words2 through17in a block ar
36、e digital audio words and check sums, as described in1.4.1. The last word in each block is a Cyclic Redundancy Check (CRC) word, as described in1.4.2. The CRC word serves the purpose of error detection on each track, while the check sums are used for correcting detected errors. The addresses of the
37、even and odd words (We and Wo), and even and odd check sums (Qe, Qo, Pe and Po) are detailed in1.4.1. SC(SYNC, ADR and auxiliary data) and CRC refer to the Sync/Control word and the CRC word. Data bit sequence Transition sequence of HDM-1 cells caused by“0000” bit sequence in the absence transitions
38、 at (*): Resulting HDM-1 cell waveform: Alternate HDM-1 cells waveform: Word 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 numbering within block Content SC We Wo We Wo We Wo Qe Qo Pe Po We Wo We Wo We Wo CRCEN 61120-3:1993 6 BSI 01-2000 As detailed in2.1.1, four blocks with block addresses00 through
39、11 correspond to one sector on the Reference track: PCM words We and Wo are recorded with MSB leading, and the same ordering is also valid for the check sums P and Q. The total signal block structure (included reference signal) and track formatting are shown as follows. Reference track: Legend: ADR
40、= Block address (BA1/2) E = Emphasis (block address00 only) PePo = P-parity X = reserved QeQo = Q-parity SYNC length p = 11 bits Block address length a = 2 bits Auxiliary data length a L = 3 bits PCM DATA length 2 d PCM = 192 bits Check data length d c = 64 bits CRC length c = 16 bits Block length b
41、 = 288 bits Sector length S =4 b = 1152 bitsEN 61120-3:1993 BSI 01-2000 7 1.2.3 The Sync/Control word Bit position1 through11 of the Sync/Control word carry a synchronization pattern violating the rules of HDM-1. As the data preceding a Sync/Control word may end with an arbitrary transition distance
42、, the synchronization pattern is defined as follows: “The synchronization pattern is characterized by two consecutive transition distances of9 cells followed by a transition distance differing from9cells”. As illustrated below, the position of block begin is defined as being3 cells before the beginn
43、ing of a synchronization pattern. Bits12 through16, as well as following bits until the next Sync/Control word, are coded in HDM-1. Bits12 and13 carry a2-bit block address which increments by one at each new block. Bits14 through16 are reserved for the storage of emphasis bits, control information,
44、other auxiliary information, and time code markers. The value of00 is specified for bits14 and15 until further definition. In blocks with block address00 on tracks1,2,3 and4 at speedI, bit16 indicates whether pre-emphasis has been used. Thus, a sequence0000 of bit16 indicates that no pre-emphasis wa
45、s used, and a sequence1000 that pre-emphasis as specified in part1 has been used. For all other tracks, a value of0 is specified for bit16 until further definition. For speedII the emphasis bit has been used on tracks1 and2. Time Diagram of the Sync/Control word: block begin Waveforms of the SYNC pa
46、ttern: Note that a SYNC pattern followed by a transition distance not equal to9 cells marks a block begin, with3cells of delay.EN 61120-3:1993 8 BSI 01-2000 1.3 Signal word distribution to tracks Input PCM words for each independant audio channel are allocated to four tracks by a matricing which is
47、defined in1.3.1 and1.3.2. 1.3.1 Track-to-channel assignment Main track number Assignment to divided channels data 8 7 6 5 4 3 2 1 2D 1D 2B 1B 2C 1C 2A 1AEN 61120-3:1993 BSI 01-2000 9 1.3.2 Signal word distribution to tracksEN 61120-3:1993 10 BSI 01-2000 1.4 Error protection method Error detection is
48、 made possible by the CRC check word recorded for each block of each track, and by theP andQ check words of each track. Error correction is made possible by theP andQ words of each individual track. 1.4.1 Interleaving and parity sums Interleaving and check word computation are based on the16-bit str
49、ucture of digital audio samples (PCMwords W). Twelve consecutive incoming PCM words form2 frames, one with odd PCM words, and one with even PCM words. The natural sequence ABCDEF becomes permuted sequence ACEBDF. P andQ check words are computed separately for odd and even PCM words. TheP check words are computed as the Exlusive-Or sum of all6PCM words of each frame. TheQ check words are computed as the Exclusive-Or sum of6 PCM words and theP check sum, with an interleave delay of D2=2 blocks, as
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