SIST EN 61120-3:1999

Digital audio tape recorder reel to reel system, using 6,3 mm magnetic tape, for professional use -- Part 3: Format B

Should be used in conjunction with EN 61120-1 and EN 61120-2.

Digitales Tonbandgerät - Spulensystem mit Magnetband 6,3 mm für Studioanwendung -- Teil 3: Format B

Système d'enregistrement à bande audionumérique, bobine à bobine, utilisant une bande magnétique de 6,3 mm, à usage professionnel -- Partie 3: Format B

Doit être lue conjointement avec les EN 61120-1 et 61120-2.

Digital audio tape recorder reel to reel system, using 6,3 mm magnetic tape, for professional use -- Part 3: Format B (IEC 61120-3:1993)

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 61120-3:1993 - Digital audio tape recorder reel to reel system, using 6,3 mm magnetic tape, for professional use - Part 3: Format B

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 61120-3:1999
01-april-1999
Digital audio tape recorder reel to reel system, using 6,3 mm magnetic tape, for
professional use -- Part 3: Format B (IEC 61120-3:1993)
Digital audio tape recorder reel to reel system, using 6,3 mm magnetic tape, for
professional use -- Part 3: Format B
Digitales Tonbandgerät - Spulensystem mit Magnetband 6,3 mm für Studioanwendung --
Teil 3: Format B
Système d'enregistrement à bande audionumérique, bobine à bobine, utilisant une
bande magnétique de 6,3 mm, à usage professionnel -- Partie 3: Format B
Ta slovenski standard je istoveten z: EN 61120-3:1993
ICS:
33.160.30 Avdio sistemi Audio systems
SIST EN 61120-3:1999 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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CEI
NORME
IEC
INTERNATIONALE
1120-3
INTERNATIONAL
Première édition
STAN DARD First edition
1991-11
Système d'enregistrement à bande audio-
numérique, bobine à bobine, utilisant une bande
à usage professionnel
magnétique de 6,3 mm,
Partie 3:
Format B
Digital audio tape recorder reel to reel system,
using 6,3 mm magnetic tape, for professional use
Part 3:
Format B
ght — all rights reserved
Droits de reproduction réservés— Copyri
© CEI 1991
Aucune partie de
cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized
utilisée sous quelque forme
que ce soit et par aucun procédé, in any form or by any means, electronic or mechanical,
électronique ou mécanique, y compris la photocopie et les including photocopying and microfilm, without permission
microfilms, sans l'accord écrit de l'éditeur. in writing from the publisher
Bureau central de la Commission Electrotechnique Inte rn
ationale 3, rue de Varembé Genève Suisse
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R
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IEC
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HoMHCCHA
• Pour p x,
• ri voir catalogue en vigueur
For price, see current catalogue

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1120-3©IEC – 3 –
CONTENTS
Page
5
FOREWORD
Clause
1 Main track recording 7
1.1 Recording modulation method 7
1.2 Signal block structure 13
1.2.1 The word format 13
13
1.2.2 The block structure
17
1.2.3 The Sync/Control word
19
1.3 Signal word distribution to tracks
19
1.3.1 Track-to-channel assignment
21
1.3.2 Signal word distribution to tracks
23
1.4 Error protection method
1.4.1 Interleaving and parity sums 23
1.4.2 The CRC word 27
29
1.5 Recording and reproducing characteristics
29
1.5.1 Reference tape
29
1.5.2 Calibration tapes
29
1.5.3 Procedure for adjusting recording current level and waveform
29
1.5.4 Specifications of tolerance relative to calibration tape
31
2 Sub-track recording
31
2.1 Digital recording method
2.1.1 Recording method on sub-track 2 31
31
2.1.1.1 The recording code
2.1.1.2 The data format 33
2.1.1.3 The synchronization pattern 33
2.1.1.4 The Control word 35
2.1.1.5 The Reference address 35
2.1.1.6 The CRC word 37
2.2 Alignment of digital audio signals and sub-track signals 37
2.2.1 Alignment of cue audio-1 and cue audio-2 track signals 37
2.2.2 Alignment of time code track signal 37
2.2.3 Alignment of Reference track signal 37

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- 5 --
1120-3©IEC
COMMISSION
INTERNATIONAL ELECTROTECHNICAL
DIGITAL AUDIO TAPE RECORDER REEL TO REEL SYSTEM,
USING 6,3 mm MAGNETIC TAPE,
FOR PROFESSIONAL USE
Part 3: Format B
FOREWORD
The formal decisions or agreements of the IEC on technical matters, prepared by Technical Committees on
1)
which all the National Committees having a special interest therein are represented, express, as nearly as
possible, an international consensus of opinion on the subjects dealt with.
They have the form of recommendations for international use and they are accepted by the National
2)
Committees in that sense.
In order to promote international unification, the IEC expresses the wish that all National Committees
3)
should adopt the text of the IEC recommendation for their national rules in so far as national conditions will
permit. Any divergence between the IEC recommendation and the corresponding national rules should, as
far as possible, be clearly indicated in the latter.
of IEC 1120 has been prepared by Sub-Committee 60A: Sound recording, of IEC
This part
Technical Committee No. 60: Recording.
should be used in conjunction with parts 1 and 2 of this standard.
This part
The text of this part is based on the following documents:
Six Months' Rule Report on Voting
60A(CO)133
60A(CO)126
Full information on the voting for the approval of this part can be found in the Voting
Report indicated in the above table.
The following IEC publications are quoted in this standard:
Publications Nos. 1120-1: Digital Audio Tape Recorder reel to reel system, using 6,3 mm magnetic tape,
for professional use - Part 1: General requirements.
Digital Audio Tape Recorder reel to reel system, using 6,3 mm magnetic tape,
1120-3:
for professional use - Part 3: Format B.
1120-4: Digital Audio Tape Recorder reel-to-reel system, using 6,3 mm magnetic tape,
for professional use - Part 4: Magnetic tape properties: Definitions and methods
of measurement. (Under consideration.)

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1120-3 0 IEC - 7 -
DIGITAL AUDIO TAPE RECORDER REEL TO REEL SYSTEM,
USING 6,3 mm MAGNETIC TAPE,
FOR PROFESSIONAL USE
Part 3: Format B
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.
T = [EDGE. (X2.X1)] + [EDGE .(X2.X1.T1+X2.X1.XO.T1.T2+X1.X2.X3.X4.T2.T4T6)]
X. = INPUT BIT DELAYED BY i BIT CLOCKS
Tj = OUTPUT WAVEFORM CELL DELAYED BY j CELL CLOCK
EDGE: TIMING VARIABLE, 0 AT CENTER, 1 AT EDGE OF BIT INTERVAL
*** Rule 1 (center transitions): A data bit sequence of "01" always leads to a center
transition in the middle of the "1" bit.

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- 9 --
1120-3©IEC
Rule 1 in HDM-1 encoding: Center transitions

1
0
Data bit sequence
r
Transition sequence of HDM-1 cells
caused by "01" bit sequence:
Resulting HDM-1 cells waveform:
Alternate HDM-1 cells waveform:
Thus, the presence in the data bit sequence of a bit pattern "01" always enforces a center
transition in the cell sequence.
*** 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.

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- 11 -
1120-3 ©IEC
Case 1: Data bit sequence "10", no transitions in the cell sequence at the positions indi-
cated by (*):
1 0
Data bit sequence
*
Transition sequence of HDM-1 cells
caused by '10" bit sequence in the
absence of transitions at (*):
Resulting HDM-1 cells waveform:
Alternate HDM-1 cells waveform:
Case 2: Every data sequence "111", no transitions in the cell sequence at the positions
indicated by (*):

1 1 1
Data bit sequence
^ *
Transition sequence of HDM-1
T
caused by "111" bit sequence in the
absence of transitions at (*):
Resulting HDM-1 cells waveform:
Alternate HDM-1 cells waveform:

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-13 -
1120-3 ©IEC
Case 3: Data sequence "0000", no transitions in the cell sequence at the positions indica-
ted by (*):
0
0
0 0
Data bit sequence
Transition sequence of H DM-1 cells
caused by "0000" bit sequence in the
absence of transitions at (*):
Resulting HDM-1 cells waveform:
Alternate HDM-1 cells waveform:
As a consequence of the rules of HDM-1 encoding, the minimum distance between tran-
sitions 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
ttern which violates the rules
consecutive run lengths of 9 cells as a synchronization pa
of HDM-1.
1.2 Signal block structure
1.2.1 The word format
A word length of 16 bits and uniform quantization with two's 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.
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 CRC

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- 15 -
1120-3 ©IEC
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.
As detailed in 2.1.1, four blocks with block addresses 00 through 11 correspond to one
sector on the Reference track:
E- - - > E - - - > E - - - > E - - - >
Block Block Block
Block
address address address address
01 10 11
00
E >
one sector
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.
S =4xb
b >
Channel
a -> E-- d
4-- p -+ E- a E-
dPCM7 c dPCM c Main
track
8
QeQo PePo CRC
SYNC ADR XX X
2
CRC 7
QeQo PePo
1
CRC 6
QeQo PePo
2
QeQo PePo CRC 5
1 SYNC ADR PCM
PCM
DATA DATA
CRC 4
SYNC ADR QeQo PePo
2
PePo CRC 3
SYNC ADR QeQo
1
2
QeQo PePo CRC
SYNC ADR
2
CRC 1
SYNC ADR XX E QeQo PePo
1
Reference track / Sub-track 2
Reference track:
16 bits
4 bits 16 bits 28 bits
ADDRESS CRC
SYNC CONTROL
^rJ
Check
Control word

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-17 -
1120-3 ©IEC
Legend:
E = Emphasis (block address 00 only)
ADR = Block address (BA1/2)
PePo = P-parity X = reserved
QeQo = 0-parity
p = 11 bits
SYNC length
2 bits
Block address length a =
= 3 bits
- Auxiliary data length
aL
192 bits
PCM DATA length =
2 x dpcM
do = 64 bits
Check data length
16 bits
CRC length c =
b = 288 bits
- Block length
1152 bits S = 4 x b =
- Sector length
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
a 2-bit block address which increments by one at each new
HDM-1. Bits 12 and 13 carry
block. Bits 14 through 16 are reserved for the storage of emphasis bits, control informa-
tion, 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 Il the emphasis bit has been used on tracks 1 and 2.

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- 19 -
1120-3©IEC
»> Time Diagram of the Sync/Control word:
block begin
E - -
E - SYNC word (16 bits)
2 bits 2 bits 1 bit
emphasis flag
-> E - - -> <->
> E— —
E - - - - - SYNC pattern
(length 11 bits) block reserved address
- - - - - HDM-1 violation - - - -> <- - - - HDM-1 coded data
Waveforms of the SYNC pattern:
SYNC
EDGE
^— 9 cells —> F— 9 cells —>
or
Note that a SYNC pattern followed by a transition distance not equal to 9 cells marks a
block begin, with 3 cells of delay.
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 defined in 1.3.1 and 1.3.2.
1.3.1 Track-to-channel assignment
Main track number Assignment to divided
channels data
2D
8
1D
7
2B
6
5 1B
4 2C
3 1C
2 2A
1A
1

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-21 -
1120-3 ©IEC
1.3.2 Signa! word distribution to tracks
A) For tape speed I
6(1), 5(1), 2(1), 1(1)
Encoder
4(1), 3(1), 2(1), 1(1)
1A
Channel 1
8(1), 7(1), 4(1), 3(1)
Encoder
1B
o Matrix
Channel 1
7(1'), 6(1'), 3(1'), 2(1')
Encoder
1C
4(1'), 3(1'), 2(1'), 1(1')
5(1'), 8(1'), 1(1'), 4(1')
Channel 1
Encoder
1D
6(2), 5(2), 2(2), 1(2)
Encoder
4(2), 3(2), 2(2), 1(2)
2A
Channel
...