BS-EN-61120-3-1994 IEC-61120-3-1991.pdf

BRITISH STANDARD BS EN 61120-3:1994 IEC 1120-3: 1991 Digital audio tape recorder reel to reel system, using 6.3 mm magnetic tape, for professional use Part 3: Format B The European Standard EN 61120-3:1993 has the status of a British Standard UDC 621.396.7:681.84.083.84:681.327.636 Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 11 09:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 61120-3:1994 This British Standard, having been prepared under the direction of the Electronic Equipment Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 January 1994 © BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference EEL/22 Draft for comment 89/22505 DC ISBN 0 580 22696 4 Cooperating organizations The European Committee for Electrotechnical Standardization (CENELEC), under whose supervision this European Standard was prepared, comprises the national committees of the following countries: AustriaItaly BelgiumLuxembourg DenmarkNetherlands FinlandNorway FrancePortugal GermanySpain GreeceSweden IcelandSwitzerland IrelandUnited Kingdom Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 11 09:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 61120-3:1994 © BSI 01-2000i Contents Page Cooperating organizationsInside front cover National forewordii Foreword2 Text of EN 61120-33 National annex NA (informative) Committees responsibleInside back cover National annex NB (informative) Cross-referencesInside back cover Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 11 09:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 61120-3:1994 ii © BSI 01-2000 National foreword This British Standard has been prepared under the direction of the Electronic Equipment Standards Policy Committee and is the English language version of EN 61120-3:1993 Digital audio tape recorder reel to reel system, using 6,3 mm magnetic tape, for professional use, Part 3: Format B, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical with IEC 1120-3:1991, published by the International Electrotechnical Commission (IEC). BS EN 61120 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 for 6.3 mm digital audio tape1). Additional information. IEC 1120-4 stated in 1.5.1 and 1.5.3 as being “(under consideration)” was published in 1992, and was implemented as BS EN 61120-4:1993. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible 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, pages i and ii, the EN title page, pages 2 to 18, an inside back cover and a back cover. This standard 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. Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 11 09:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN 61120-3 October 1993 UDC 621.396.7:681.84.083.84:681.327.636 Descriptors: Audio recording, digital recording, magnetic tape, code, format, recording characteristics, recording track English version Digital audio tape recorder reel to reel system, using 6,3 mm magnetic tape, for professional use Part 3: Format B (IEC 1120-3:1991) Système denregistrement à bande audionumérique, bobine à bobine, utilisant une bande magnétique de 6,3 mm, à usage professionnel Partie 3: Format B (CEI 1120-3:1991) Digitales Tonbandgerät Spulensystem mit Magnetband 6,3 mm für Studioanwendungen Teil 3: Format B (IEC 1120-3:1991) This European Standard was approved by CENELEC on 1993-09-22. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard 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 Central 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 status 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 Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels © 1993 Copyright reserved to CENELEC members Ref. No. EN 61120-3:1993 E Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 11 09:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 61120-3:1993 © BSI 01-2000 2 Foreword The CENELEC questionnaire procedure, performed for finding out whether or not the International Standard IEC 1120-3:1991 could be accepted without textual changes, has shown that no common modifications were necessary for the acceptance as European Standard. The reference document was submitted to the CENELEC members for formal vote and was approved by CENELEC as EN 61120-3 on 22 September 1993. The following dates were fixed: For products which have complied with the relevant national standard before 1994-09-01, as shown by the manufacturer or by a certification body, this previous standard may continue to apply for production until 1999-09-01. Annexes designated “normative” are part of the body of the standard. In this standard, Annex ZA is normative. Contents Page Foreword2 1Main track recording3 1.1Recording modulation method3 1.2Signal block structure5 1.2.1The word format5 1.2.2The block structure5 1.2.3The Sync/Control word7 1.3Signal word distribution to tracks8 1.3.1Track-to-channel assignment8 1.3.2Signal word distribution to tracks9 1.4Error protection method10 1.4.1Interleaving and parity sums10 1.4.2The CRC word12 1.5Recording and reproducing characteristics12 1.5.1Reference tape12 1.5.2Calibration tapes13 1.5.3Procedure for adjusting recording current level and waveform13 1.5.4Specifications of tolerance relative to calibration tape13 Page 2Sub-track recording13 2.1Digital recording method13 2.1.1Recording method on sub-track 213 2.1.1.1The recording code13 2.1.1.2The data format14 2.1.1.3The synchronization pattern14 2.1.1.4The Control word15 2.1.1.5The Reference address15 2.1.1.6The CRC word16 2.2Alignment of digital audio signals and sub-track signals16 2.2.1Alignment of cue audio-1 and cue audio-2 track signals16 2.2.2Alignment of time code track signal16 2.2.3Alignment of Reference track signal16 Annex ZA (normative) Other international publications quoted in this standard with the references of the relevant European publications17 Figure 1 Computation of P and Q check words10 Figure 2 Analytical expression for computing P and Q check words10 Figure 3 Contents of one block, referred to one track input sequence11 Figure 4 Contents of one block for all tracks, referred to one audio channel input11 Figure 5 Contents of 4 simultaneous blocks from one audio channel12 Figure 6 Contents of the Sync/Control word in each block12 latest date of publication of an identical national standard(dop) 1994-09-01 latest date of withdrawal of conflicting national standards(dow) 1994-09-01 Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 11 09:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 61120-3:1993 © BSI 01-20003 Electrical requirements for recording and reproducing equipment. 1 Main track recording 1.1 Recording 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 channel-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 input bit are defined in the following formulation and bit to waveform transitions are defined in rules 1 and 2. * Formulation for bit to waveform modulation. * Rule 1 (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 the data bit sequence of a bit pattern “01” always enforces a center transition in the cell sequence. Rule 1 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: Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 11 09:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 61120-3:1993 4 © BSI 01-2000 * Rule 2 (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 cell 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 sequence 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: Alternate HDM-1 cells waveform: Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 11 09:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 61120-3:1993 © BSI 01-20005 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 is 3 cells. The maximum distance is 9 cells, and two consecutive transition distances cannot be both equal to 9 cells. This makes it possible to use two consecutive run lengths of 9 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 of 16 bits and uniform quantization 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 of 18 words of 16 bits. The first word in a block is called the Sync/Control word, and is described in 1.2.3. The words 2 through 17 in a block are digital audio words and check sums, as described in 1.4.1. The last word in each block is a Cyclic Redundancy Check (CRC) word, as described in 1.4.2. 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 even and odd words (We and Wo), and even and odd check sums (Qe, Qo, Pe and Po) are detailed in 1.4.1. 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 at (*): Resulting HDM-1 cell waveform: Alternate HDM-1 cells waveform: Word123456789101112131415161718 numbering within block ContentSCWeWoWeWoWeWoQeQoPePoWeWoWeWoWeWoCRC Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 11 09:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 61120-3:1993 6 © BSI 01-2000 As detailed in 2.1.1, four blocks with block addresses 00 through 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 =Block address (BA1/2)E = Emphasis (block address 00 only) PePo =P-parityX = reserved QeQo =Q-parity SYNC lengthp =11 bits Block address lengtha =2 bits Auxiliary data lengthaL=3 bits PCM DATA length2 × dPCM=192 bits Check data lengthdc=64 bits CRC lengthc =16 bits Block lengthb =288 bits Sector lengthS = 4 × b = 1152 bits Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 11 09:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 61120-3:1993 © BSI 01-20007 1.2.3 The Sync/Control word Bit position 1 through 11 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, the synchronization pattern is defined as follows: “The synchronization pattern is characterized by two consecutive transition distances of 9 cells followed by a transition distance differing from 9 cells”. As illustrated below, the position of block begin is defined as being 3 cells before the beginning of a synchronization pattern. Bits 12 through 16, as well as following bits until the next Sync/Control word, are coded in HDM-1. Bits 12 and 13 carry a 2-bit block address which increments by one at each new block. Bits 14 through 16 are reserved for the storage of emphasis bits, control information, other auxiliary information, and time code markers. The value of 00 is specified for bits 14 and 15 until further definition. In blocks with block address 00 on tracks 1, 2, 3 and 4 at speed I, bit 16 indicates whether pre-emphasis has been used. Thus, a sequence 0000 of bit 16 indicates that no pre-emphasis was used, and a sequence 1000 that pre-emphasis as specified in part 1 has been used. For all other tracks, a value of 0 is specified for bit 16 until further definition. For speed II the emphasis bit has been used on tracks 1 and 2. Time Diagram of the Sync/Control word: block begin Waveforms of the SYNC pattern: Note that a SYNC pattern followed by a transition distance not equal to 9 cells marks a block begin, with 3 cells of delay. Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 11 09:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 61120-3:1993 8 © BSI 01-2000 1.3 Signal word distribution to tracks Input PCM words