SIST EN 61595-2:1999

Multichannel digital audio tape recorder (DATR), reel-to-reel system, for professional use -- Part 2: Format B

Applies to 24 to 96 channel digital audio recording on 12,7 mm or 25,4 mm wide tape hereinafter called tape), with stationary heads, for professional use. Defines the mechanical and electrical characteristics necessary to ensure the interchangeability of programmes, recorded as digital audio signals on magnetic tape, in professional industries.

Digitales Mehrkanal-Tonbandgerät (DATR), Spulensystem für Studioanwendungen -- Teil 2: Format B

Système d'enregistrement à bande audionumérique multivoie (DATR), bobine à bobine, à usage professionnel -- Partie 2: Format B

S'applique à l'enregistrement audionumérique de 24 à 96 voies, sur des bandes d'une largeur de 12,7 mm ou de 25,4 mm, (appelées plus loin bandes), avec des têtes fixes, pour un usage professionel. Définit les caractéristiques mécaniques et électriques nécessaires pour assurer, entre professionnels, l'interchangeabilité des programmes et des signaux audionumériques enregistrés sur bandes magnétiques.

Multichannel digital audio tape recorder (DATR), reel-to-reel system, for professional use -- Part 2: Format B (IEC 61595-2:1997)

General Information

• Status: Published
• Publication Date: 31-Mar-1999
• ICS: 33.160.30 - Audio systems
• Technical Committee: AVM - Audio, video and multimedia systems and equipment
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Apr-1999
• Due Date: 01-Apr-1999
• Completion Date: 01-Apr-1999
• Ref Project: EN 61595-2:1998 - Multichannel digital audio tape recorder (DATR), reel-to-reel system, for professional use - Part 2: Format B

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 61595-2:1999
01-april-1999
Multichannel digital audio tape recorder (DATR), reel-to-reel system, for
professional use -- Part 2: Format B (IEC 61595-2:1997)
Multichannel digital audio tape recorder (DATR), reel-to-reel system, for professional use
-- Part 2: Format B
Digitales Mehrkanal-Tonbandgerät (DATR), Spulensystem für Studioanwendungen --
Teil 2: Format B
Système d'enregistrement à bande audionumérique multivoie (DATR), bobine à bobine,
à usage professionnel -- Partie 2: Format B
Ta slovenski standard je istoveten z: EN 61595-2:1998
ICS:
33.160.30 Avdio sistemi Audio systems
SIST EN 61595-2:1999 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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NORME
CEI
INTERNATIONALE
IEC
61595-2
INTERNATIONAL
Première édition
STANDARD
First edition
1997-06
Système d'enregistrement à bande
audionumérique multivoies (DATR),
bobine à bobine, à usage professionnel –
Partie 2:
Format B
Multichannel digital audio tape recorder (DATR),
reel-to-reel system, for professional use –
Part 2:
Format B
 IEC 1997 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun any form or by any means, electronic or mechanical,
procédé, électronique ou mécanique, y compris la photo- including photocopying and microfilm, without permission in
copie et les microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: [phone] e-mail: [e-mail] IEC web site http: //www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale
U
PRICE CODE
International Electrotechnical Commission
Pour prix, voir catalogue en vigueur
For price, see current catalogue

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61595-2 © IEC:1997 – 3 –
CONTENTS
Page
FOREWORD . 7
Clause
1 Scope . 9
2 Normative references. 9
3 Definitions. 9
3.1 Data flow of a digital audio tape recorder. 9
4 Digital encoding . 13
4.1 Sampling frequency . 13
4.2 Sampling timing . 13
4.3 Quantization . 13
5 Tape speed. 13
6 Tape width and number of digital audio channels. 13
7 Tape winding . 15
8 Reel and hub . 15
9 Allocation and dimension of magnetic tracks . 15
10 Assignment of magnetic tracks. 15
11 Emphasis. 23
12 Main track recording . 23
12.1 Recording modulation method. 23
12.1.1 Rule 1 (centre transitions) . 25
12.1.2 Rule 2 (edge transitions) . 25
12.2 Signal block structure. 29
12.2.1 The word format. 29
12.2.2 The block structure . 29
12.2.3 The sync/control word . 33
12.3 Track-to-channel assignment . 33
12.4 Error protection method . 41
12.4.1 Interleaving and parity sums. 41
12.4.2 The CRC word . 43
12.5 Recording and reproducing characteristics . 45
12.5.1 Reference tape . 45
13 Subtrack recording. 45
13.1 Time code channel (time code track). 45
13.2 Auxiliary data channel . 45
13.2.1 Reference track . 45
13.2.2 Auxiliary data channel (auxiliary data track) . 51
13.3 Auxiliary analogue channel (cue audio-1 track and/or cue audio-2 track). 51

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61595-2 © IEC:1997 – 5 –
Page
13.4 Alignment of digital audio signals and subtrack signals. 51
13.4.1 Alignment of cue audio-1 and cue audio-2 track signals. 51
13.4.2 Alignment of time code track signal . 51
13.4.3 Alignment of reference track signal. 51
Annex A – Bibliography. 53
Tables
1 Tape width and number of digital audio channels. 15
2 Track assignment. 15
3 Block structure. 29
4 24-channel version. 35
5 48-channel version. 37
6 96-channel version. 39
Figures
1 Data flow of the main audio channels of a DATR (digital audio tape recorder) . 11
2 Recording channels of a DATR (digital audio tape recorder) . 11
3 Reproducing channels of a DATR (digital audio tape recorder) . 13
4 Track pattern for DATR on magnetic tape (28 tracks with 12,7 mm tape width) . 17
5 Track pattern for DATR on magnetic tape (52 tracks with 12,7 mm tape width) . 19
6 Track pattern for DATR on magnetic tape (103 tracks with 25,4 mm tape width) . 21
7 Emphasis characteristics. 23
8 Rule 1 (centre transitions) . 25
9 Rule 2 (edge transitions) case 1 . 27
10 Rule 2 (edge transitions) case 2 . 27
11 Rule 2 (edge transitions) case 3 . 29
12 Block address . 31
13 The total signal block structure. 31
14 Time diagram of the sync/control word . 33
15 Computation of P and Q check words. 41
16 Contents of one block, referred to one track input sequence . 43
17 Range of CRC word . 43
18 Biphase-mark coding rules . 47
19 Word format of the reference track word . 47
20 The synchronization pattern and definition of the beginning of a sector . 49
21 Control word . 49
22 Effective computation range of the CRC word. 51

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61595-2 © IEC:1997 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_________
MULTICHANNEL DIGITAL AUDIO TAPE RECORDER (DATR),
REEL-TO-REEL SYSTEM, FOR PROFESSIONAL USE –
Part 2: Format B
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61595-2 has been prepared by subcommittee 100B: Recording, of
IEC technical committee 100: Audio, video and multimedia systems and equipment.
The text of this standard is based on the following documents:
FDIS Report on voting
100B/49/FDIS 100B/67/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
IEC 61595 consists of the following parts, under the general title: Multichannel digital audio
tape recorder (DATR), reel-to-reel system, for professional use:
– Part 1: Format A
– Part 2: Format B
– Part 3: 24 bit use of 16 bit media
Annex A is for information only.

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61595-2 © IEC:1997 – 9 –
MULTICHANNEL DIGITAL AUDIO TAPE RECORDER (DATR),
REEL-TO-REEL SYSTEM, FOR PROFESSIONAL USE –
Part 2: Format B
1 Scope
This part of IEC 61595 applies to 24 to 96 channel digital audio recording on 12,7 mm or
25,4 mm wide tape (hereinafter called tape), with stationary heads, for professional use. It
defines 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,
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 editions of the normative documents indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60461: 1986, Time and control code for video tape recorders
IEC 61120-4: 1992, Digital audio tape recorder reel-to-reel system, using 6,3 mm magnetic
tape, for professional use – Part 4: Magnetic tape properties: definitions and method of
measurement
ITU-T V.41: 1988, Code-independent error control system
3 Definitions
For the purpose of this part of IEC 61595, the following definitions apply.
3.1 Data flow of a digital audio tape recorder
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.

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61595-2 © IEC:1997 – 11 –
Analogue input
A/D
Encoder Modulator
converter
Digital input
Write amplifier
+ head
Digital
audio
interface
Digital output
Tape
D/A
Decoder
Read head
converter
Analogue output + amplifier
Time base
Demodulator
corrector
IEC  754/97
Figure 1 – Data flow of the main audio channels of a DATR (digital audio tape recorder)
Digital
Digital audio
audio input
interface Digital Modulator
Main
audio and write
tracks
A/D
Analogue
processing amplifier
converter
audio input
Analogue
audio input 1
Auxiliary channels for audio
Analogue
audio input 2
cueing and/or data modulator
Auxiliary
Subtracks
data input
Auxiliary data input
Auxiliary data channel modulator
(reference signal)
Time code
Time code channel modulator
input
IEC  755/97
Figure 2 – Recording channels of a DATR (digital audio tape recorder)

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61595-2 © IEC:1997 – 13 –
Digital audio
Digital
Demodulator
interface audio output
Digital audio
Main
read
tracks
processing
amplifier
D/A
Analogue
converter
audio output
Analogue
audio output 1
Auxiliary channels
Analogue
for audio cueing and/or
audio output 2
data demodulator
Auxiliary
data output
Subtracks
Auxiliary
Auxiliary data channel
data output
demodulator
(reference signal)
Time code
Time code channel demodulator
output
IEC  756/97
Figure 3 – Reproducing channels of a DATR (digital audio tape recorder)
4 Digital encoding
4.1 Sampling frequency
The sampling frequency shall be 48 kHz, and the accuracy of the sampling frequency at
–6
encoding shall be ± 50 × 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, 2 s complement
code. Positive numbers correspond to positive analogue voltages at the input.
5 Tape speed
The tape speed shall be nominal 76,20 cm/s. The tolerance on tape speed shall be
within 0,2 %.
6 Tape width and number of digital audio channels
0 0

The tape width shall be 25,37 mm (nominal 25,4 mm) or 12,66 mm (nominal
−0,03 −0,02
12,7 mm). Table 1 shows tape width and number of digital audio channels.

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61595-2 © IEC:1997 – 15 –
Table 1 – Tape width and number of digital audio channels
Items Contents
Tape width (mm) 25,4 12,7
Number of audio channels 96 48 24
Main 96 48 24
Number of tracks Sub 7 4 4
Total 103 52 28
Main tracks / audio channels 1/1 1/1 1/1
7 Tape winding
The magnetic coating faces the centre of the reel.
8 Reel and hub
Under consideration.
9 Allocation and dimension of magnetic tracks
The figures 4, 5 and 6 show the track allocations on magnetic tape.
10 Assignment of magnetic tracks
If the tape moves from the left to 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
Track number
Tape width (mm) 25,4 12,7
Main Digital audio 4.99 2.25, 28.51 2.13; 16.27
Time code 3 26 14
Type of track Cue audio-1 1 1 1
Sub
Cue audio-2 103 52 28
Reference 101 27 15
Auxiliary data 2, 100, 102 1* 1*
* Refer to 13.2.2.

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61595-2 © IEC:1997 – 17 –
IEC  759/97
Figure 4 – Track pattern for DATR on magnetic tape (28 tracks with 12,7 mm tape width)

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61595-2 © IEC:1997 – 19 –
IEC  760/97
Figure 5 – Track pattern for DATR on magnetic tape (52 tracks with 12,7 mm tape width)

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61595-2 © IEC:1997 – 21 –
IEC  761/97
Figure 6 – Track pattern for DATR on magnetic tape (103 tracks with 25,4 mm tape width)

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61595-2 © IEC:1997 – 23 –
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 7.
+ 15
+ 10
Pre-emphasis
+ 6 dB / oct
+ 5
0
– 5
De-emphasis
– 6 dB / oct
– 10
– 15
3,18 k 10,6 k
(50 μs) (15 μs)
1 k 2 k 4 k 8 k 20 k
Frequency (Hz)
IEC  762/97
Figure 7 – Emphasis characteristics
12 Main track recording
12.1 Recording modulation method
In this subclause, the modulation of a binary data sequence ("incoming data") into a record
signal waveform ("output waveform") is specified. Next, a synchronization pattern violating the
modulation rules is defined.
The data to be recorded on the main tracks are first channel-coded. A run-length-limited code
called HDM-1 is used, which is not d.c. free.
The output w
...