IEC 61603-8-1:2003

Transmission of audio and/or video and related signals using infrared radiation - Part 8-1: Digital audio and related signals

IEC 61603-8-1:2003 specifies the characteristics and measuring methods for digital audio signal transmission systems using infrared radiation with sub-carrier of the frequency ranges 3 MHz to 6 MHz. It describes systems with different economic uses of the available bandwidth in order to obtain minimum interference and maximum compatibility. It replaces 6.8.3 of IEC 61603-2. This bilingual version, published in 2011-04, corresponds to the English version.

Transmission de signaux audio et/ou vidéo et de signaux similaires par rayonnement infrarouge - Partie 8-1: Signaux audio numériques et similaires

La CEI 61603-8-1:2003 spécifie les caractéristiques et les méthodes de mesure de systèmes de transmission de signaux audio numériques par rayonnement infrarouge avec des sous-porteuses entre 3 MHz et 6 MHz. Elle décrit des systèmes avec des utilisations économiquement différentes de la bande passante disponible en vue d'un brouillage minimal et d'une compatibilité maximale. Elle remplace le 6.8.3 de la CEI 61603-2. La présente version bilingue, publiée en 2011-04, correspond à la version anglaise.

General Information

• Status: Published
• Publication Date: 03-Nov-2003
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 33.040.20 - Transmission systems
• ICS: 33.160.99 - Other audio, video and audiovisual equipment
• Technical Committee: TA 4 - Digital system interfaces and protocols
• Drafting Committee: PT 61603-8-1 - TC 100/PT 61603-8-1
• Current Stage: PPUB - Publication issued
• Start Date: 04-Nov-2003
• Completion Date: 30-Nov-2003

Overview

IEC 61603-8-1:2003 is an international standard that defines the characteristics and measurement methods for digital audio signal transmission using infrared radiation. It covers systems that use a sub-carrier in the 3 MHz to 6 MHz frequency range and describes band allocation and system options that balance bandwidth economy, interference minimization and compatibility. The standard replaces clause 6.8.3 of IEC 61603-2 and is part of the IEC 61603 series on transmission of audio/video and related signals using infrared radiation.

Key topics and technical requirements

The standard addresses the full transmitter–receiver chain and specifies measurable requirements and procedures, including:

• Band allocation and sub-carrier planning for infrared (IR) digital audio links (3–6 MHz sub-carrier range).
• System architecture: functional partitioning, block diagrams and channel allocation for multi-channel digital audio.
• Source and transmission stream structure: framing, headers, CRC/ parity and error-correction schemes (including Reed–Solomon style blocks and parity matrices shown in the document).
• Modulation and baseband processing: mapping, symbol conversion and practical modulation techniques (document includes QPSK mapping and baseband filter characteristics).
• Performance measurements: test conditions, transmitting distance and directivity, spurious emissions, and accuracy of transmission-check frequencies.
• Marking and specification content required for compliant equipment.
• Normative annexes for consumer and professional audio modes, with specific source_info and sub-frame structures.

Applications and who uses this standard

IEC 61603-8-1 is intended for manufacturers, system integrators, test laboratories and standards engineers working on infrared wireless audio systems. Typical practical applications include:

• IR digital audio links for consumer electronics (wireless headphones, set-top box to audio devices) and professional audio (studio or venue links, assistive-listening systems).
• Design and verification of IR transmitters and receivers with specified directivity, spurious emission limits and modulation characteristics.
• Development of interoperable products that require compatibility and minimized interference in shared IR bands.

Related standards

• IEC 61603 series - broader guidance on transmission of audio/video and related signals using infrared radiation.
• IEC 61603-2 - earlier parts of the series (IEC 61603-8-1 replaces clause 6.8.3 of this part).

Keywords: IEC 61603-8-1, infrared transmission, digital audio, sub-carrier 3–6 MHz, IR audio standard, modulation, band allocation, measurement methods, Reed–Solomon, QPSK.

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD
61603-8-1
First edition
2003-11
Transmission of audio and/or video and
related signals using infrared radiation –
Part 8-1:
Digital audio and related signals
Reference number
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.
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edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the
base publication incorporating amendment 1 and the base publication incorporating
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INTERNATIONAL IEC
STANDARD
61603-8-1
First edition
2003-11
Transmission of audio and/or video and
related signals using infrared radiation –
Part 8-1:
Digital audio and related signals
 IEC 2003  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail]  Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale
X
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – 61603-8-1  IEC:2003(E)
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references. 7
3 Terms, definitions and abbreviations. 7
4 System description . 8
4.1 General . 8
4.2 Area of application. 9
4.3 Band allocation. 9
5 General characteristics .11
5.1 Environment conditions for operation.11
5.2 Partition of functions between elements of the systems .11
6 Specific requirements .11
6.1 Block diagram.11
6.2 Input and output .12
6.3 Carrier .12
6.4 Sub-carrier .12
6.5 Channel allocation .12
6.6 Block structure.14
6.7 Source stream .14
6.8 Transmission stream .19
6.9 Modulation.20
7 Characteristics and measurements .26
7.1 Test conditions .26
7.2 Location.26
7.3 Transmitting distance and directivity.26
7.4 Spurious level.28
7.5 Accuracy of transmission-check frequency.28
8 Marking and contents of specifications.28
8.1 Marking .28
8.2 Contents of specifications.28
Annex A (normative) Application of the transmission systems for digital audio and
related signals using infrared radiation in the consumer audio mode .33
Annex B (normative) Application of the transmission systems for digital audio and
related signals using infrared radiation in the professional audio mode .42

61603-8-1  IEC:2003(E) – 3 –
Figure 1 – System concept. 9
Figure 2 – IEC 61603 band allocation.10
Figure 3 – Band allocation.10
Figure 4 – Transmitter.11
Figure 5 – Channel-coding block .12
Figure 6 – Channel allocation.13
Figure 7 – Block structure .14
Figure 8 – Source stream.15
Figure 9 – Source_block stream.15
Figure 10 – Source_info stream .16
Figure 11 – Block alignment .17
Figure 12 – Parity check matrix .18
Figure 13 – Error correction code block.18
Figure 14 – Transmission stream .19
Figure 15 – The order bytes in Tr_section .20
Figure 16 – Modulation block .21
Figure 17 – Byte to symbol conversion.21
Figure 18 – XOR gates.22
Figure 19 – Scramble pattern generator .22
Figure 20 – QPSK mapping.23
Figure 21 – Baseband filter characteristics.24
Figure 22 – Transmission chain.29
Figure 23 – Location for measurements .29
Figure 24 – Transmitting distance .29
Figure 25 – Angle of half optical radiant intensity .29
Figure 26 – Optical axis of the transmitter .30
Figure 27 – Optical axis of the receiver .30
Figure 28 – Characteristics of the transmitter .30
Figure 29 – Directivity characteristics of the transmitter .31
Figure 30 – Characteristics of the receiver .31
Figure 31 – Directivity characteristics of the receiver.32
Figure 32 – Measuring system for spurious emission .32
Figure A.1 – Source_info structure .33
Figure A.2 – crc_area.38
Figure A.3 – Linear feedback shift register circuit.38
Figure A.4 – Sub-frame structure of full-band mode .39
Figure A.5 – Sub-frame structure of half-band mode .41
Figure B.1 – Source_info structure .42
Figure B.2 – CRC area.46
Figure B.3 – Linear feedback shift register circuit.47
Figure B.4 – Sub-frame structure of full-band mode .47
Figure B.5 – Sub-frame structure of half-band mode .50

– 4 – 61603-8-1  IEC:2003(E)
Table 1 – Analogue audio channel allocation.10
Table 2 – Sub-carrier frequency .12
Table 3 – Maximum source stream bit rate .13
Table 4 – Bit rate of digital audio.13
Table 5 – Byte values in a transmission_info.16
Table 6 – Reed-Solomon code parameter .17
Table 7 – Header bit field .20
Table 8 – Marking and contents of specifications .28
Table A.1 – crc_flag .35
Table A.2 – Valid_flag .35
Table A.3 – Data_type.35
Table A.4 .36
Table A.5 – Mode_extension_code.36
Table A.6 – pro_flag.36
Table A.7 – pcm_id .36
Table A.8 – Copyright_flag.37
Table A.9 – Emphasis .37
Table A.10 – fs_code .37
Table A.11 – Mode_extension_code.40
Table B.1 – Crc_flag .44
Table B.2 – Valid_flag .44
Table B.3 – Data_type.44
Table B.4 – Coding_mode .44
Table B.5 – Mode_extension_code.45
Table B.6 – pro_flag.45
Table B.7 – pcm_id .45
Table B.8 – Emphasis .45
Table B.9 – fs_code .46
Table B.10 – Mode_extension_code.49

61603-8-1  IEC:2003(E) – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TRANSMISSION OF AUDIO AND/OR VIDEO AND RELATED SIGNALS
USING INFRARED RADIATION –
Part 8-1: Digital audio and related signals
AVANT-PROPOS
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International Standard IEC 61603-8-1 has been prepared by technical area 3, Infrared
systems and applications, of IEC technical committee 100: Audio, video and multimedia
systems and equipment.
This part of IEC 61603 replaces 6.8.3 of IEC 61603-2.
The text of this standard is based on the following documents:
FDIS Report on voting
100/628/FDIS 100/706/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.

– 6 – 61603-8-1  IEC:2003(E)
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
2005. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
61603-8-1  IEC:2003(E) – 7 –
TRANSMISSION OF AUDIO AND/OR VIDEO RELATED SIGNALS USING
INFRARED RADIATION –
Part 8-1: Digital audio and related signals
1 Scope
This part of IEC 61603 specifies the characteristics and measuring methods for digital audio
signal transmission systems using infrared radiation with sub-carrier of the frequency ranges
3 MHz to 6 MHz. It describes systems with different economic uses of the available bandwidth
in order to obtain minimum interference and maximum compatibility.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60958-1, Digital Audio Interface – Part 1: General
IEC 60958-3, Digital Audio Interface – Part 3: Consumer applications
IEC 60958-4, Digital Audio Interface – Part 4: Professional applications
IEC 61603-1:1997, Transmission of audio and/or video and related signals using infrared
radiation – Part 1: General
IEC 61603-2:1997, Transmission of audio and/or video and related signals using infrared
radiation – Part 2: Transmission systems for audio wide band and related signals
IEC 61937:2000, Digital audio – Interface for non-linear PCM encoded audio bitstreams
applying IEC 60958
IEC 61938, Audio and audiovisual systems – Interconnections and matching values –
Preferred matching values of analogue signals
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purposes of this part of IEC 61603, the definitions given in Part 1 together with the
following apply.
3.1.1
source stream
source_block stream with a corresponding source_info stream and transmission_info stream
3.1.2
block_structure
structure of data and parties for transmission

– 8 – 61603-8-1  IEC:2003(E)
3.1.3
Tr_section
interleaved stream from the block_structure
3.2 Abbreviations
For the purposes of this part of IEC 61603, the following abbreviations apply.
IR infrared (see IEC 61603-1)
PD photo diode
O/E optical/ electrical
Tx transmitter/ radiator
Rx receiver
QPSK quadrature phase shift keying
DQPSK differential encoded QPSK
Transmission_info transmission information
CRC cyclic redundancy check
source_info source information
Sync Gen. sync pattern generator
Header Gen. header generator
GF galois field
RS Reed-Solomon code
ECC error correction code
4 System description
4.1 General
This part of 61603 defines an application using digital audio signals based on the digital audio
interface, IEC 60958, for professional and consumer applications. This includes an ability to
transmit non-linear PCM data formatted according to IEC 61937.
The digital audio bitstream transmission systems that are the subject of this document are
characterized by the following features:
– used for interface with infrared radiation,
– harmonized with IEC 60958;
– harmonized with IEC 61937;
– used for multi-channel transmission in future;
– signal block structure;
– error correction;
– frequency range: 3 MHz to 6 MHz;
– channel coding;
– low spurious (band-pass filter).
This standard gives the detailed specifications of the digital audio signal transmission.
Infrared digital audio signal transmission is used in a frequency range of 3 MHz to 6 MHz as
specified in IEC 61603-2. It shares this range with analogue audio applications, so that care
should be taken to avoid interference with any such applications being used simultaneously.

61603-8-1  IEC:2003(E) – 9 –
This system supports a full-band mode that carries all the data on the IEC 60958 interface at
sample rates of 48 kHz and below. It also supports a half-band mode carrying two streams
each of two 16-bit audio channels without the capacity for all the associated validity data, user
data, or channel status data defined in IEC 60958. Some of those data are carried elsewhere
in the system.
Depending on the applicable bit rate, two different channel bandwidths are possible. One is
called the full-band mode, which carries 2 channels, 32-slot bit stream with the bandwidth of
3 MHz wide, the other is called the half-band mode, which carries 2 channels, 16-slot bit
stream with the bandwidth of 1,5 MHz wide.
Both the full-band mode and half-band mode are based on IEC 60958-1, IEC 60958-3,
IEC 60958-4 and IEC 61937.
The system concept is shown in Figure 1.
Digital
audio Transmitter
equipment
Infrared
Infrared Infrared
radiator detector
Digital
audio
Receiver
equipment
IEC  2495/03
Figure 1 – System concept
4.2 Area of application
This digital audio signal transmission system using infrared radiation is mainly used for
transmitting digital audio signals from a CD player, DAT player or MD player, etc. to
headphones, speakers and infrared receivers, etc.
4.3 Band allocation
In IEC 61603-2, the band allocation for high quality audio transmission ranges from 2 MHz to
6 MHz is as shown in Figure 2.

– 10 – 61603-8-1  IEC:2003(E)
Remote
control                    High speed remote control
system                   system / Data transmission
0, 04   0,1 1
2               6     10         30   MHz
Sub-carrier
Audio transmission / Conference           High-fidelity
Video transmission
systems (analogue and digital)             audio transmission
IEC  2496/03
Figure 2 – IEC 61603 band allocation
There are 8 channels in this band, named H1 through H8, for analogue audio signals, as
defined in Table 1.
In general, wireless loudspeaker or wireless headphone systems use H1 and H2 for left and
right channels, so this format for digital audio uses channel allocation from H3 to H8.
Table 1 – Analogue audio channel allocation
Name Sub-carrier
H1 2,3 MHz
H2 2,8 MHz
H3 3,2 MHz
H4 3,7 MHz
H5 4,3 MHz
H6 4,8 MHz
H7 5,2 MHz
H8 5,7 MHz
Figure 3 shows the channel allocation for this digital audio format together with analogue
channel allocation.
Digital audio transmission
High-fidelity audio
transmission
23 4 5 6MHz
H1 H2 H3 H4 H5 H6 H7 H8
Sub-carrier
IEC  2497/03
Figure 3 – Band allocation
61603-8-1  IEC:2003(E) – 11 –
5 General characteristics
5.1 Environment conditions for operation
The environmental conditions for the equipment are mainly defined in relevant standards for
individual units. However, unless otherwise specified, the equipment shall be capable of
operating at least within the temperature and relative humidity ranges:
5 °C to 40 °C, and 25 % RH to 75 % RH
Systems and apparatus in accordance with this standard are primarily used indoors, with the
advantage of operating more than one system interference-free in adjacent rooms.
5.2 Partition of functions between elements of the systems
Due to the different applications for different room sizes, equipment is designed in various
combinations of functional blocks. For home applications it is desirable to have only a few
blocks of small size and low installation cost.
6 Specific requirements
6.1 Block diagram
Figure 4 shows a block diagram of the transmitter described in Figure 1. Figure 5 shows a
block diagram of the channel-coding block. The signal from sync gen., header gen. and
Tr_section are multiplexed into the transmission stream.
to infrared
Channel coding
source stream
Modulation block
radiator
block
Transmission stream
IEC  2498/03
Figure 4 – Transmitter
– 12 – 61603-8-1  IEC:2003(E)
Transmission_info stream
Sync generator
Block_structure
(Buffer)
Header
Source_block stream
generator
Transmission
Source
stream
stream
Tr_section
Source_info stream
ECC
IEC  2499/03
Figure 5 – Channel-coding block
6.2 Input and output
The digital audio signals at input and output shall be in accordance with IEC 61938.
6.3 Carrier
The carrier shall use infrared wavelengths between 800 nm and 900 nm.
6.4 Sub-carrier
The sub-carrier modulates the carrier of infrared. In this format, the sub-carrier band ranges
from 3 MHz to 6 MHz.
6.5 Channel allocation
6.5.1 General
Figure 6 shows the channel allocation of digital audio signal transmission using infrared
radiation, with the frequencies of each sub-carrier. The signal has a dual modulation. The
infrared signal is intensity-modulated by the sub-carrier, which is DQPSK-modulated with the
digital audio signals.
6.5.2 Sub-carrier frequency
Table 2 shows the values of sub-carrier frequency.
Table 2 – Sub-carrier frequency
f
sub-carrier
divcode Number of channels
MHz
0 1 4,5
1 2 3,75  5,25
Figure 6 shows two kinds of transmission channel allocation.

61603-8-1  IEC:2003(E) – 13 –
4,5 MHz
divcode = 0
#0
Full-band mode
3 5 6 MHz
Sub-carrier frequency
5,25 MHz
3,75 MHz
divcode = 1
#0 #1
Half-band mode
2 3 45 6 MHz
Sub-carrier frequency
IEC  2500/03
Figure 6 – Channel allocation
6.5.3 Bit rate
The maximum source stream bit rate is shown in Table 3.
Table 3 – Maximum source stream bit rate
divcode Rate Number of channels
0 3,072 Mbps 1
1 1,536 Mbps 2
For reference, Table 4 shows bit rate of digital audio.
Table 4 – Bit rate of digital audio
Bit rate Digital audio signal
3,072 Mbps 48 kHz, 32 bit, 2 ch
1,536 Mbps 48 kHz, 16 bit, 2 ch
2,8224 Mbps 44,1 kHz, 32 bit, 2 ch
1,4112 Mbps 44,1 kHz, 16 bit, 2 ch
2,048 Mbps 32 kHz, 32 bit, 2 ch
1,024 Mbps 32 kHz, 16 bit, 2 ch

– 14 – 61603-8-1  IEC:2003(E)
6.6 Block structure
“Source stream” to “Tr_section” conversion is based on the block structure in Figure 7. Each
symbol in this structure has a size of 1 byte.
cn (Column number)
58 byte
48 byte 10 byte
B
0,0 B
0,1
B
0,47
B
0,2
B
0,57
B
1,0
Parity
Data bytes
bytes
B
32,57
B
32,0
IEC  2501/03
Figure 7 – Block structure
A byte in Figure 7 is defined as:
Β
rn,cn
where
rn is the row number
cn is the column number
In Figure 7, left-upper corner is byte B and right-lower corner is byte B .
00, 32,57
6.7 Source stream
6.7.1 General
“Source stream” consists of a “source_block stream” with a corresponding “source_info
stream” and a “transmission_info stream.”
As shown in Figure 8, the “source_block stream”, “source_info stream” and “transmission_info
stream” are simultaneous.
rn (Row number)
33 Rows
61603-8-1  IEC:2003(E) – 15 –
Time
Source-
Source- Source- Source- Source-
block
block block block block
Source- Source- Source-  Source- Source-
info info info info info
Transmission-Transmission-Transmission-Transmission-Transmission-
info info info info info
IEC  2502/03
Figure 8 – Source stream
6.7.2 Source_block stream
The data clock frequency of the “source_block stream” should be a multiple of one of
48 kHz
44,1 kHz
32 kHz
For example, the clock is 44,1 kHz × 32, when transmitting CD audio.
The “source_block stream” is composed of a series of continuous “source_blocks”, each of
which consists of 1 536 bytes .
The format of the “source_block” is defined in Annexes A and B.
Figure 9 shows this format.
Time
Source Source Source Source Source
block block block block block
1 byte
1 536 byte
IEC  2503/03
Figure 9 – Source_block stream
The order of each byte in the “source_block” is shown as follows:
B0,0  B0,1  B0,2  . B0,47  B1,0 B1,1  . B31,47
6.7.3 Source_info stream
The “source_info stream” is composed of a continuous source_info made up from 40 bytes.
The format of “source_info” is defined in Annexes A and B.

– 16 – 61603-8-1  IEC:2003(E)
Figure 10 shows the format of the “source_info stream.”
Time
Source-  Source-  Source-  Source-  Source-
info info info info info
1 byte
40 byte
IEC  2504/03
Figure 10 – Source_info stream
The order of each byte in the “source_info” is shown as follows:
B32,0  B32,1  B32,2  . B32,38  B32,39
6.7.4 Transmission_info stream
“Transmission_info stream” is composed of a continuous “transmission_info” made up from
8 bytes.
Each byte of “transmission_info” is defined in Table 5.
Table 5 – Byte values in a transmission_info
B32.cn Default value Meaning
40 0 Reserved
41 0 Reserved
42 0 Reserved
43 0 Reserved
44 0 Reserved
45 0 Reserved
46-47 – SectionID
SectionID is a serial number, modulo 0x10 000 (65 536), incremented at each “source_block”
to show the serial number of the “source_block.”
6.7.5 Block alignment
Figure 11 shows alignment of the “source_block”, “source_info”, and “transmission_info” in
the “block-structure.”
61603-8-1  IEC:2003(E) – 17 –
cn (Column number)
58 byte
48 byte 10 byte
Source_block
Transmission_info
Source_info
1 row
8 byte
40 byte
IEC  2505/03
Figure 11 – Block alignment
6.7.6 Forward error correction code
A forward error correction policy is chosen in this format for error correction, because there is
no feedback information.
The chosen error correction code is Reed-Solomon code on GF (2 ).
Table 6 – Reed-Solomon code parameter
8 4 3 2
Primitive polynomial
p()x = x + x + x + x +1
i
g(x) = (x −α )
Generator polynomial
∏
i=0
MSB  LSB
Primitive element
[00000010]
Code length 58
Parity length 10
Parity check matrix (Hp) used in “block_structure” is shown in Figure 12.
rn (Row number)
33 rows
32 rows
– 18 – 61603-8-1  IEC:2003(E)
Data (48 byte) Parity (10 byte)
B B B B B B B B B B B B B
m0 m1 m2 m3 m4 m5 m45 m46 m47 m48 m49 m56 m57
1 1 1 1 ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ 1 1 1 1
 
 57 56 55 54 3 2 
α α α α ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ α α α 1
 
114 112 110 108 6 4 2
 
α α α α ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ α α α 1
 
171 168 165 162 9 6 3
Hp = α α α α ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ α α α 1
 
 
⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅
 
⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅
 
 513 504 495 486 27 18 9 
α α α α ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ α α α 1
 
 B 
rn,0
 
B
rn,1
 
 
B
rn,2
 
B
rn,3
 
 
⋅
 
⋅
 
 
Vp = B
rn,45
 
B 
rn,46
 
B
rn,47
 
 
⋅
 
⋅
 
 
B
rn,56
 
B
 
rn,57
 
IEC  2506/03
where
Hp×Vp = [0]
Figure 12 – Parity check matrix
The alignment of error correction code blocks in “block_structure” is shown in Figure 13.
Data (48 byte) Parity (10 byte)
Β
rn.
0 1 2 3 4 5 45 46 47 48 49 50 56 57
Column number
IEC  2507/03
Figure 13 – Error correction code block

61603-8-1  IEC:2003(E) – 19 –
6.8 Transmission stream
6.8.1 Ratio of transmission stream data to source_block stream data
The ratio R of “transmission stream” data to “source_block stream” data is as follows:
B_ts 1920
R = = = 1,25
B_sb 1 536
where:
R is the ratio of transmission stream data to source_block stream data;
B_ts is the number of bytes contained in a block structure of transmission stream;
B_sb is the number of bytes contained in a block structure of source_block stream.
6.8.2 Transmission stream format
6.8.2.1 General
The transmission stream format is specified in Figure 14.
(A) Chapter Chapter Chapter
(B)
Header
Sync Tr_section
2 byte
4 byte 1 914 byte
IEC  2508/03
Figure 14 – Transmission stream
bit stream: continuous chapters
Chapter: Sync + Header + Tr_section
Sync: bit pattern (“01111011 01111011 01111011 01111011”)
Header: bit field parameter (16 bit)
Tr_Section: 1 914 byte (= 15 312 bit)
The “‘header” is not protected by error correction code.
6.8.2.2 Sync
“Sync” is a 32 bit (4 byte) long pattern. Sync is the beginning of the chapter.
6.8.2.3 Header
The header bit field parameter is defined in Table 7.

– 20 – 61603-8-1  IEC:2003(E)
Table 7 – Header bit field
Contents Bit-width Default bit Meaning
pattern
reserved 7 0000000 -
divcode 1 - division code : 0-1
reserved 7 0000000 -
chnum 1 - channel number
“Divcode” and “chnum” are used for defining respectively the division code and channel
number of the sub-carrier for frequency-division multiplex transmission.
When “divcode” = 0, the transmission mode is called the "full-band mode", and when
“divcode” = 1, the mode is called the "half-band mode". These modes are described in 6.5.2.
6.8.2.4 Tr_section
“Tr_section (transmission_section)” is made up from 1 914 byte, and forms a block structure.
The order of bytes in “Tr_section” is shown as follows:
B0,0  B1,0  B2,0  . B32,0  B0,1  B1,1 B2,1  . B30,57 B31,57 B32,57
Figure 15 shows the order of bytes in Tr_section.
58 byte
Tr_section
IEC  2509/03
Figure 15 – The order bytes in Tr_section
6.9 Modulation
6.9.1 Modulation block
6.9.1.1 General
The modulation block is illustrated in Figure 16.
33 rows
61603-8-1  IEC:2003(E) – 21 –
The modulation block has the function of byte to symbol conversion, scrambler, differential
encoder and QPSK modulator. The QPSK modulator consists of signal mapping and
baseband filters.
Transmission
Byte to
-stream
symbol Scrambler
conversion
Baseband
filter
⊗
cos( )
Differential  Signal
encoder mapping
⊕
To
π⁄2
infrared
radiator
−sin( )
Baseband
filter
⊗
QPSK modulator
IEC  2510/03
Figure 16 – Modulation block
6.9.1.2 Byte to symbol conversion
A transmission stream is composed of bytes, and should thus be converted to 2-bit pairs (a
symbol) for feeding DQPSK modulator. Figure 17 shows how to convert a transmission stream
byte to a 2-bit symbol.
Byte B Byte B+1
From transmission-stream
b7  b6 b5  b4 b3  b2 b1  b0 b7  b6 b5  b4 b3  b2 b1  b0
(bytes) b7  b b7  b b7  b b7  b b7  b b7  b666666 b b b b b b555555  b4  b4  b4  b4  b4  b4 b3 b3 b3 b3 b3 b3  b2 b2 b2 b2 b2 b2 b1  b1  b1  b1  b1  b1  b0b0b0b0b0b0   b7  b6b7  b6b7  b6b7  b6b7  b6b7  b6 b5 b5 b5 b5 b5 b5  b4  b4  b4  b4  b4  b4 b3 b3 b3 b3 b3 b3  b2 b2 b2 b2 b2 b2 b1  b b1  b b1  b b1  b b1  b b1  b000000
MSB LSB MSB LSB
To scrambler
x x x x x x x x x x x x x x x x
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0
(2 bits symbol)
Symbol Symbol Symbol Symbol Symbol Symbol Symbol Symbol
SySySySySySymmmmmmbbbbbboooooollllll SSSSSSyyyyyymmmmmmbolbolbolbolbolbol SSSSSSyyyyyymmmmmmbolbolbolbolbolbol SSSSSSyyyyyymmmmmmbolbolbolbolbolbol SySySySySySymmmmmmbbbbbboooooollllll SSSSSSyyyyyymmmmmmbolbolbolbolbolbol SSSSSSyyyyyymmmmmmbolbolbolbolbolbol S S S S S Syyyyyymmmmmmbolbolbolbolbolbol
z  z+1  z+2  z+3  z+4  z+5  z+6  z+7
zzzzzz            z+z+z+z+z+z+111111            z+z+z+z+z+z+222222            z+z+z+z+z+z+333333            z+z+z+z+z+z+444444            z+z+z+z+z+z+555555            z+z+z+z+z+z+666666            z+z+z+z+z+z+777777
IEC  2511/03
Figure 17 – Byte to symbol conversion
In Figure 17, b7 is the most significant bit (MSB) of a byte, and b0 is the least significant bit
(LSB) of a byte. Therefore b7 of a byte is converted to x1 of a symbol.

– 22 – 61603-8-1  IEC:2003(E)
6.9.1.3 Scramble
A scrambler is used for scrambling a symbol pattern for DQPSK to obtain spectrum shaping.
DQPSK is adopted to ensure enough binary transitions for clock recovery.
A scrambler consists of XOR gates as shown in Figure 18 and the scramble pattern
generator, which consists of a pseudo random binary sequence (PRBS) generator and a
counter, as shown in Figure 19.
x
y
from byte to
symbol
x
i :
converter q
1 to differential
y :
encoder
x
from scramble
y
q
i :
pattern
generator
q
IEC  2512/03
Figure 18 – XOR gates
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
Load
Initialize
3 4 5 6 7 8 9 10 11 12 13 14 15 16
0 1 2
Transmission
clock
))
PRBS generator
))
q
))
q
MSB
Counter
0-7
IEC  2513/03
Enable
Figure 19 – Scramble pattern generator
The length of the PRBS is 17 bits and it is initialized at every chapter header. The polynomial
for the PRBS generator is
3 17
1+ x + x
61603-8-1  IEC:2003(E) – 23 –
and the initial pattern is
Initial pattern : "10101010101010101".
The counter is a 3 bit counter and is initialized to “0” at every chapter header.
Thus the first symbol output of the scramble pattern generator after initialization is “01”, and
the next is “10”.
Scrambling is not applied to “sync” in order to prevent confusion of patterns.
6.9.1.4 Differential encoder
Differential encoding is used, to obtain a π/2 rotation-invariance QPSK constellation.
The encoding rule is defined as follows:
I(k) = (y (k) ⊕ y (k))(y (k) ⊕ I(k −1)) +(y (k) ⊕ y (k))(y (k) ⊕Q(k −1))
1 0 1 1 0 1
Q(k) = (y (k) ⊕ y (k))(y (k) ⊕Q(k −1) +(y (k) ⊕ y (k))(y (k) ⊕ I(k −1))
1 0 0 1 0 0
6.9.1.5 Signal mapping
The signal mapping of QPSK is defined as:
z(k) =[](1−2I(k)) + j(1−2Q(k)) .
The signal mapping of QPSK is shown in Figure 20. “I” and “Q” axes are orthogonal.
Q
10 00
I
11 01
IEC  2514/03
Figure 20 – QPSK mapping
6.9.1.6 Baseband filter
The baseband filter of the modulation block is illustrated in Figure 16.
The filter has a theoretical function defined as follows:

– 24 – 61603-8-1  IEC:2003(E)
H ( f ) = 1, f < f ⋅ (1 − α)
N
 
 f − f 
1 1 π
 
N
H ( f ) = + sin
  
, f ⋅ (1 −α) ≤ f ≤ f ⋅ (1+ α) ,
N N
2 2 2 f α
 
N
 
 
f > f ⋅ (1 + α)
N
H ( f ) = 0,
where
H(f) is the signal amplitude;
f =1/(2T ) is the Nyquist frequency;
N s
T is the symbol interval;
s
(1/T)= 0,625×bit rate;
s
α = 0,3 is the Roll off factor.
The amplitude characteristic of the baseband filter is shown in Figure 21.
H(f)
rm
0 dB
Frequency
In-band ripple rm ≤1,0 dB
−3,0 dB
rm
−30,0 dB
0,7f f 1,3f
N N N
IEC  2515/03
Figure 21 – Baseband filter characteristics
The filter should have a linear phase within the pass band (f ≤ f ) and the group delay ripple
N
should be less than 0,1T .
s
6.9.2 Modulation method
The modulation method of this format is intensity modulation of the carrier by using QPSK.

61603-8-1  IEC:2003(E) – 25 –
6.9.2.1 Sub-carrier
The sub-carrier frequency of the full-band mode shall be 4,5 MHz and that of the half-band
mode shall be 3,75 MHz or 5,25 MHz.
6.9.2.2 Frequency accuracy
The frequency accuracy of the sub-carrier shall be ± 0,1%.
6.9.2.3 Occupied bandwidth
The occupied bandwidth is determined as follows:
Bandwidth (in Hz) = 0,8125 × bit rate (in bps)

– 26 – 61603-8-1  IEC:2003(E)
Example:
32 bit slots specified in IEC 60958
3,072 × 0,8125 = 2,496 MHz (in case of 48 kHz sampling frequency)
2,8224 × 0,8125 = 2,34195 MHz (in case of 44,1 kHz sampling frequency)
2,048 × 0,8125 = 1,664 MHz (in case of 32 kHz sampling frequency)
7 Characteristics and measurements
7.1 Test conditions
Temperature: 15 °C to 35 °C
Humidity: 45 % RH to 75 % RH
Brightness: 500 lx to 1 000 lx (on the surface of the receiver)
Normal (i.e. not operating at high frequency) fluorescent lamps shall be used.
7.2 Location
A sufficiently large room should be used for test, so the reflection of infrared from the walls,
floor and ceiling is negligible. The location specified in Figure 23 may be used if a correc
...

IEC 61603-8-1 ®
Edition 1.0 2003-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Transmission of audio and/or video and related signals using infrared
radiation –
Part 8-1: Digital audio and related signals

Transmission de signaux audio et/ou vidéo et de signaux similaires par
rayonnement infrarouge –
Partie 8-1: Signaux audio numériques et similaires

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IEC 61603-8-1 ®
Edition 1.0 2003-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Transmission of audio and/or video and related signals using infrared
radiation –
Part 8-1: Digital audio and related signals

Transmission de signaux audio et/ou vidéo et de signaux similaires par
rayonnement infrarouge –
Partie 8-1: Signaux audio numériques et similaires

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
X
CODE PRIX
ICS 33.040.20; 33.160.99 ISBN 978-2-88912-443-5
– 2 – 61603-8-1  IEC:2003
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviations . 7
3.1 Terms and definitions . 7
3.2 Abbreviations . 8
4 System description . 8
4.1 General . 8
4.2 Area of application . 9
4.3 Band allocation . 9
5 General characteristics . 11
5.1 Environment conditions for operation . 11
5.2 Partition of functions between elements of the systems . 11
6 Specific requirements . 11
6.1 Block diagram . 11
6.2 Input and output . 12
6.3 Carrier . 12
6.4 Sub-carrier . 12
6.5 Channel allocation . 12
6.6 Block structure . 14
6.7 Source stream . 14
6.8 Transmission stream . 19
6.9 Modulation . 21
7 Characteristics and measurements . 26
7.1 Test conditions . 26
7.2 Location . 26
7.3 Transmitting distance and directivity . 26
7.4 Spurious level . 28
7.5 Accuracy of transmission-check frequency . 28
8 Marking and contents of specifications . 28
8.1 Marking . 28
8.2 Contents of specifications . 28
Annex A (normative) Application of the transmission systems for digital audio and
related signals using infrared radiation in the consumer audio mode . 33
Annex B (normative) Application of the transmission systems for digital audio and
related signals using infrared radiation in the professional audio mode . 42

Figure 1 – System concept . 9
Figure 2 – IEC 61603 band allocation . 10
Figure 3 – Band allocation . 10
Figure 4 – Transmitter . 11
Figure 5 – Channel-coding block . 12
Figure 6 – Channel allocation . 13
Figure 7 – Block structure . 14
Figure 8 – Source stream . 15

61603-8-1  IEC:2003 – 3 –
Figure 9 – Source_block stream. 15
Figure 10 – Source_info stream . 16
Figure 11 – Block alignment . 17
Figure 12 – Parity check matrix . 18
Figure 13 – Error correction code block . 19
Figure 14 – Transmission stream . 19
Figure 15 – The order bytes in Tr_section . 20
Figure 16 – Modulation block . 21
Figure 17 – Byte to symbol conversion . 22
Figure 18 – XOR gates . 22
Figure 19 – Scramble pattern generator . 23
Figure 20 – QPSK mapping. 24
Figure 21 – Baseband filter characteristics . 25
Figure 22 – Transmission chain . 29
Figure 23 – Location for measurements . 29
Figure 24 – Transmitting distance . 29
Figure 25 – Angle of half optical radiant intensity . 29
Figure 26 – Optical axis of the transmitter . 30
Figure 27 – Optical axis of the receiver . 30
Figure 28 – Characteristics of the transmitter . 30
Figure 29 – Directivity characteristics of the transmitter . 31
Figure 30 – Characteristics of the receiver . 31
Figure 31 – Directivity characteristics of the receiver . 32
Figure 32 – Measuring system for spurious emission . 32
Figure A.1 – Source_info structure . 33
Figure A.2 – crc_area . 38
Figure A.3 – Linear feedback shift register circuit . 38
Figure A.4 – Sub-frame structure of full-band mode . 39
Figure A.5 – Sub-frame structure of half-band mode . 41
Figure B.1 – Source_info structure . 42
Figure B.2 – CRC area . 46
Figure B.3 – Linear feedback shift register circuit . 47
Figure B.4 – Sub-frame structure of full-band mode . 47
Figure B.5 – Sub-frame structure of half-band mode . 50

Table 1 – Analogue audio channel allocation . 10
Table 2 – Sub-carrier frequency . 12
Table 3 – Maximum source stream bit rate . 13
Table 4 – Bit rate of digital audio . 13
Table 5 – Byte values in a transmission_info . 16
Table 6 – Reed-Solomon code parameter . 17
Table 7 – Header bit field . 20
Table 8 – Marking and contents of specifications . 28

– 4 – 61603-8-1  IEC:2003
Table A.1 – crc_flag . 35
Table A.2 – Valid_flag . 35
Table A.3 – Data_type . 35
Table A.4 . 36
Table A.5 – Mode_extension_code . 36
Table A.6 – pro_flag . 36
Table A.7 – pcm_id . 36
Table A.8 – Copyright_flag. 37
Table A.9 – Emphasis . 37
Table A.10 – fs_code . 37
Table A.11 – Mode_extension_code . 40
Table B.1 – Crc_flag . 44
Table B.2 – Valid_flag . 44
Table B.3 – Data_type . 44
Table B.4 – Coding_mode . 44
Table B.5 – Mode_extension_code . 45
Table B.6 – pro_flag . 45
Table B.7 – pcm_id . 45
Table B.8 – Emphasis . 45
Table B.9 – fs_code . 46
Table B.10 – Mode_extension_code . 49

61603-8-1  IEC:2003 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TRANSMISSION OF AUDIO AND/OR VIDEO
AND RELATED SIGNALS USING INFRARED RADIATION –

Part 8-1: Digital audio and related signals

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61603-8-1 has been prepared by technical area 3, Infrared
systems and applications, of IEC technical committee 100: Audio, video and multimedia
systems and equipment.
This part of IEC 61603 replaces 6.8.3 of IEC 61603-2.
This bilingual version, published in 2011-04, corresponds to the English version.
The text of this standard is based on the following documents:
FDIS Report on voting
100/628/FDIS 100/706/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.

– 6 – 61603-8-1  IEC:2003
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
61603-8-1  IEC:2003 – 7 –
TRANSMISSION OF AUDIO AND/OR VIDEO
AND RELATED SIGNALS USING INFRARED RADIATION –

Part 8-1: Digital audio and related signals

1 Scope
This part of IEC 61603 specifies the characteristics and measuring methods for digital audio
signal transmission systems using infrared radiation with sub-carrier of the frequency ranges
3 MHz to 6 MHz. It describes systems with different economic uses of the available bandwidth
in order to obtain minimum interference and maximum compatibility.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60958-1, Digital audio interface – Part 1: General
IEC 60958-3, Digital audio interface – Part 3: Consumer applications
IEC 60958-4, Digital audio interface – Part 4: Professional applications
IEC 61603-1:1997, Transmission of audio and/or video and related signals using infra-red
radiation – Part 1: General
IEC 61603-2:1997, Transmission of audio and/or video and related signals using infra-red
radiation – Part 2: Transmission systems for audio wide band and related signals
IEC 61937:2000, Digital audio – Interface for non-linear PCM encoded audio bitstreams
applying IEC 60958
IEC 61938, Audio and audiovisual systems – Interconnections and matching values –
Preferred matching values of analogue signals
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purposes of this part of IEC 61603, the definitions given in Part 1 together with the
following apply.
3.1.1
source stream
source_block stream with a corresponding source_info stream and transmission_info stream
3.1.2
block_structure
structure of data and parties for transmission

– 8 – 61603-8-1  IEC:2003
3.1.3
Tr_section
interleaved stream from the block_structure
3.2 Abbreviations
For the purposes of this part of IEC 61603, the following abbreviations apply.
IR infrared (see IEC 61603-1)
PD photo diode
O/E optical/ electrical
Tx transmitter/ radiator
Rx receiver
QPSK quadrature phase shift keying
DQPSK differential encoded QPSK
Transmission_info transmission information
CRC cyclic redundancy check
source_info source information
Sync Gen. sync pattern generator
Header Gen. header generator
GF galois field
RS Reed-Solomon code
ECC error correction code
4 System description
4.1 General
This part of 61603 defines an application using digital audio signals based on the digital audio
interface, IEC 60958, for professional and consumer applications. This includes an ability to
transmit non-linear PCM data formatted according to IEC 61937.
The digital audio bitstream transmission systems that are the subject of this document are
characterized by the following features:
– used for interface with infrared radiation,
– harmonized with IEC 60958;
– harmonized with IEC 61937;
– used for multi-channel transmission in future;
– signal block structure;
– error correction;
– frequency range: 3 MHz to 6 MHz;
– channel coding;
– low spurious (band-pass filter).
This standard gives the detailed specifications of the digital audio signal transmission.
Infrared digital audio signal transmission is used in a frequency range of 3 MHz to 6 MHz as
specified in IEC 61603-2. It shares this range with analogue audio applications, so that care
should be taken to avoid interference with any such applications being used simultaneously.

61603-8-1  IEC:2003 – 9 –
This system supports a full-band mode that carries all the data on the IEC 60958 interface at
sample rates of 48 kHz and below. It also supports a half-band mode carrying two streams
each of two 16-bit audio channels without the capacity for all the associated validity data, user
data, or channel status data defined in IEC 60958. Some of those data are carried elsewhere
in the system.
Depending on the applicable bit rate, two different channel bandwidths are possible. One is
called the full-band mode, which carries 2 channels, 32-slot bit stream with the bandwidth of
3 MHz wide, the other is called the half-band mode, which carries 2 channels, 16-slot bit
stream with the bandwidth of 1,5 MHz wide.
Both the full-band mode and half-band mode are based on IEC 60958-1, IEC 60958-3,
IEC 60958-4 and IEC 61937.
The system concept is shown in Figure 1.
Digital
audio Transmitter
equipment
Infrared
Infrared Infrared
radiator detector
Digital
Receiver audio
equipment
IEC  2495/03
Figure 1 – System concept
4.2 Area of application
This digital audio signal transmission system using infrared radiation is mainly used for
transmitting digital audio signals from a CD player, DAT player or MD player, etc. to
headphones, speakers and infrared receivers, etc.
4.3 Band allocation
In IEC 61603-2, the band allocation for high quality audio transmission ranges from 2 MHz to
6 MHz is as shown in Figure 2.

– 10 – 61603-8-1  IEC:2003
Remote
control                    High speed remote control
system                   system / Data transmission
0, 04   0,1 1
2               6     10         30   MHz
Sub-carrier
Audio transmission / Conference           High-fidelity
Video transmission
systems (analogue and digital)             audio transmission
IEC  2496/03
Figure 2 – IEC 61603 band allocation
There are 8 channels in this band, named H1 through H8, for analogue audio signals, as
defined in Table 1.
In general, wireless loudspeaker or wireless headphone systems use H1 and H2 for left and
right channels, so this format for digital audio uses channel allocation from H3 to H8.
Table 1 – Analogue audio channel allocation
Name Sub-carrier
H1 2,3 MHz
H2 2,8 MHz
H3 3,2 MHz
H4 3,7 MHz
H5 4,3 MHz
H6 4,8 MHz
H7 5,2 MHz
H8 5,7 MHz
Figure 3 shows the channel allocation for this digital audio format together with analogue
channel allocation.
Digital audio transmission
High-fidelity audio
transmission
2 3 4 5 6 MHz
H1 H2 H3 H4 H5 H6 H7 H8
Sub-carrier
IEC  2497/03
Figure 3 – Band allocation
61603-8-1  IEC:2003 – 11 –
5 General characteristics
5.1 Environment conditions for operation
The environmental conditions for the equipment are mainly defined in relevant standards for
individual units. However, unless otherwise specified, the equipment shall be capable of
operating at least within the temperature and relative humidity ranges:
5 °C to 40 °C, and 25 % RH to 75 % RH
Systems and apparatus in accordance with this standard are primarily used indoors, with the
advantage of operating more than one system interference-free in adjacent rooms.
5.2 Partition of functions between elements of the systems
Due to the different applications for different room sizes, equipment is designed in various
combinations of functional blocks. For home applications it is desirable to have only a few
blocks of small size and low installation cost.
6 Specific requirements
6.1 Block diagram
Figure 4 shows a block diagram of the transmitter described in Figure 1. Figure 5 shows a
block diagram of the channel-coding block. The signal from sync gen., header gen. and
Tr_section are multiplexed into the transmission stream.
to infrared
Channel coding
source stream
Modulation block
radiator
block
Transmission stream
IEC  2498/03
Figure 4 – Transmitter
– 12 – 61603-8-1  IEC:2003
Transmission_info stream
Sync generator
Block_structure
(Buffer)
Header
Source_block stream
generator
Transmission
Source
stream
stream
Tr_section
Source_info stream
ECC
IEC  2499/03
Figure 5 – Channel-coding block
6.2 Input and output
The digital audio signals at input and output shall be in accordance with IEC 61938.
6.3 Carrier
The carrier shall use infrared wavelengths between 800 nm and 900 nm.
6.4 Sub-carrier
The sub-carrier modulates the carrier of infrared. In this format, the sub-carrier band ranges
from 3 MHz to 6 MHz.
6.5 Channel allocation
6.5.1 General
Figure 6 shows the channel allocation of digital audio signal transmission using infrared
radiation, with the frequencies of each sub-carrier. The signal has a dual modulation. The
infrared signal is intensity-modulated by the sub-carrier, which is DQPSK-modulated with the
digital audio signals.
6.5.2 Sub-carrier frequency
Table 2 shows the values of sub-carrier frequency.
Table 2 – Sub-carrier frequency
f
sub-carrier
divcode Number of channels
MHz
0 1 4,5
1 2 3,75  5,25
Figure 6 shows two kinds of transmission channel allocation.

61603-8-1  IEC:2003 – 13 –
4,5 MHz
divcode = 0
#0
Full-band mode
3 5 6 MHz
Sub-carrier frequency
5,25 MHz
3,75 MHz
divcode = 1
#0 #1
Half-band mode
2 3 4 5 6 MHz
Sub-carrier frequency
IEC  2500/03
Figure 6 – Channel allocation
6.5.3 Bit rate
The maximum source stream bit rate is shown in Table 3.
Table 3 – Maximum source stream bit rate
divcode Rate Number of channels
0 3,072 Mbps 1
1 1,536 Mbps 2
For reference, Table 4 shows bit rate of digital audio.
Table 4 – Bit rate of digital audio
Bit rate Digital audio signal
3,072 Mbps 48 kHz, 32 bit, 2 ch
1,536 Mbps 48 kHz, 16 bit, 2 ch
2,8224 Mbps 44,1 kHz, 32 bit, 2 ch
1,4112 Mbps 44,1 kHz, 16 bit, 2 ch
2,048 Mbps 32 kHz, 32 bit, 2 ch
1,024 Mbps 32 kHz, 16 bit, 2 ch

– 14 – 61603-8-1  IEC:2003
6.6 Block structure
“Source stream” to “Tr_section” conversion is based on the block structure in Figure 7. Each
symbol in this structure has a size of 1 byte.
cn (Column number)
58 byte
48 byte 10 byte
B
0,0 B
0,1
B
0,47
B
0,2
B
0,57
B
1,0
Parity
Data bytes
bytes
B
32,57
B
32,0
IEC  2501/03
Figure 7 – Block structure
A byte in Figure 7 is defined as:
Β
rn,cn
where
rn is the row number
cn is the column number
In Figure 7, left-upper corner is byte B and right-lower corner is byte B .
0,0 32,57
6.7 Source stream
6.7.1 General
“Source stream” consists of a “source_block stream” with a corresponding “source_info
stream” and a “transmission_info stream.”
As shown in Figure 8, the “source_block stream”, “source_info stream” and “transmission_info
stream” are simultaneous.
rn (Row number)
33 Rows
61603-8-1  IEC:2003 – 15 –
Time
Source- Source- Source- Source- Source-
block
block block block block
Source- Source- Source-  Source- Source-
info info info info info
Transmission-Transmission-Transmission-Transmission-Transmission-
info info info info info
IEC  2502/03
Figure 8 – Source stream
6.7.2 Source_block stream
The data clock frequency of the “source_block stream” should be a multiple of one of
48 kHz
44,1 kHz
32 kHz
For example, the clock is 44,1 kHz × 32, when transmitting CD audio.
The “source_block stream” is composed of a series of continuous “source_blocks”, each of
which consists of 1 536 bytes.
The format of the “source_block” is defined in Annexes A and B.
Figure 9 shows this format.
Time
Source Source Source Source Source
block block block block block
1 byte
1 536 byte
IEC  2503/03
Figure 9 – Source_block stream
The order of each byte in the “source_block” is shown as follows:
B0,0  B0,1  B0,2  . B0,47  B1,0 B1,1  . B31,47
6.7.3 Source_info stream
The “source_info stream” is composed of a continuous source_info made up from 40 bytes.
The format of “source_info” is defined in Annexes A and B.

– 16 – 61603-8-1  IEC:2003
Figure 10 shows the format of the “source_info stream.”
Time
Source-  Source-  Source-  Source-  Source-
info info info info info
1 byte
40 byte
IEC  2504/03
Figure 10 – Source_info stream
The order of each byte in the “source_info” is shown as follows:
B32,0  B32,1  B32,2  . B32,38  B32,39
6.7.4 Transmission_info stream
“Transmission_info stream” is composed of a continuous “transmission_info” made up from
8 bytes.
Each byte of “transmission_info” is defined in Table 5.
Table 5 – Byte values in a transmission_info
B32.cn Default value Meaning
40 0 Reserved
41 0 Reserved
42 0 Reserved
43 0 Reserved
44 0 Reserved
45 0 Reserved
46-47 – SectionID
SectionID is a serial number, modulo 0x10 000 (65 536), incremented at each “source_block”
to show the serial number of the “source_block.”
6.7.5 Block alignment
Figure 11 shows alignment of the “source_block”, “source_info”, and “transmission_info” in
the “block-structure.”
61603-8-1  IEC:2003 – 17 –
cn (Column number)
58 byte
48 byte 10 byte
Source_block
Transmission_info
Source_info
1 row
8 byte
40 byte
IEC  2505/03
Figure 11 – Block alignment
6.7.6 Forward error correction code
A forward error correction policy is chosen in this format for error correction, because there is
no feedback information.
The chosen error correction code is Reed-Solomon code on GF (2 ).
Table 6 – Reed-Solomon code parameter
8 4 3 2
Primitive polynomial
p(x)= x + x + x + x +1
i
g(x) = (x −α )
Generator polynomial
∏
i=0
MSB  LSB
Primitive element
[00000010]
Code length 58
Parity length 10
Parity check matrix (Hp) used in “block_structure” is shown in Figure 12.
rn (Row number)
33 rows
32 rows
– 18 – 61603-8-1  IEC:2003
Data (48 byte) Parity (10 byte)
B B B B B B B B B B B B B
m0 m1 m2 m3 m4 m5 m45 m46 m47 m48 m49 m56 m57
 1 1 1 1 ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ 1 1 1 1
 57 56 55 54 3 2 
α α α α ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ α α α 1
 
114 112 110 108 6 4 2
 
α α α α ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ α α α 1
 
171 168 165 162 9 6 3
Hp = α α α α ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ α α α 1
 
 
⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅
 
⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅
 
513 504 495 486 27 18 9
 
α α α α ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ α α α 1
 
 B 
rn,0
 
B
rn,1
 
 B 
rn,2
 
B
rn,3
 
 
⋅
 
⋅
 
 
B
Vp =
rn,45
 
B
 
rn,46
 
B
rn,47
 
 
⋅


⋅
 
 
B
rn,56
 
B
 
rn,57


IEC  2506/03
where
Hp×Vp = [0]
Figure 12 – Parity check matrix
The alignment of error correction code blocks in “block_structure” is shown in Figure 13.

61603-8-1  IEC:2003 – 19 –
Data (48 byte) Parity (10 byte)
Β
rn.
0 1 2 3 4 5 45 46 47 48 49 50 56 57
Column number
IEC  2507/03
Figure 13 – Error correction code block
6.8 Transmission stream
6.8.1 Ratio of transmission stream data to source_block stream data
The ratio R of “transmission stream” data to “source_block stream” data is as follows:
B_ts 1920
R = = = 1,25
B_sb 1536
where:
R is the ratio of transmission stream data to source_block stream data;
B_ts is the number of bytes contained in a block structure of transmission stream;
B_sb is the number of bytes contained in a block structure of source_block stream.
6.8.2 Transmission stream format
6.8.2.1 General
The transmission stream format is specified in Figure 14.
(A) Chapter Chapter Chapter
(B)
Header
Tr_section
Sync
2 byte
4 byte 1 914 byte
IEC  2508/03
Figure 14 – Transmission stream
Bit stream: continuous chapters
Chapter: Sync + Header + Tr_section
Sync: bit pattern (“01111011 01111011 01111011 01111011”)
Header: bit field parameter (16 bit)
Tr_Section: 1 914 byte (= 15 312 bit)
The “‘header” is not protected by error correction code.

– 20 – 61603-8-1  IEC:2003
6.8.2.2 Sync
“Sync” is a 32 bit (4 byte) long pattern. Sync is the beginning of the chapter.
6.8.2.3 Header
The header bit field parameter is defined in Table 7.
Table 7 – Header bit field
Contents Bit-width Default bit Meaning
pattern
reserved 7 0000000 -
divcode 1 - division code : 0-1
reserved 7 0000000 -
chnum 1 - channel number
“Divcode” and “chnum” are used for defining respectively the division code and channel
number of the sub-carrier for frequency-division multiplex transmission.
When “divcode” = 0, the transmission mode is called the "full-band mode", and when
“divcode” = 1, the mode is called the "half-band mode". These modes are described in 6.5.2.
6.8.2.4 Tr_section
“Tr_section (transmission_section)” is made up from 1 914 byte, and forms a block structure.
The order of bytes in “Tr_section” is shown as follows:
B0,0  B1,0  B2,0  . B32,0  B0,1  B1,1 B2,1  . B30,57 B31,57 B32,57
Figure 15 shows the order of bytes in Tr_section.
58 byte
Tr_section
IEC  2509/03
Figure 15 – The order bytes in Tr_section
33 rows
61603-8-1  IEC:2003 – 21 –
6.9 Modulation
6.9.1 Modulation block
6.9.1.1 General
The modulation block is illustrated in Figure 16.
The modulation block has the function of byte to symbol conversion, scrambler, differential
encoder and QPSK modulator. The QPSK modulator consists of signal mapping and
baseband filters.
Transmission
Byte to
-stream
symbol Scrambler
conversion
Baseband
filter
⊗
cos( )
Differential  Signal
encoder mapping
⊕
To
π⁄2
infrared
radiator
−sin( )
Baseband
filter
⊗
QPSK modulator
IEC  2510/03
Figure 16 – Modulation block
6.9.1.2 Byte to symbol conversion
A transmission stream is composed of bytes, and should thus be converted to 2-bit pairs (a
symbol) for feeding DQPSK modulator. Figure 17 shows how to convert a transmission stream
byte to a 2-bit symbol.
– 22 – 61603-8-1  IEC:2003
Byte B Byte B+1
From transmission-stream
b7  b6 b5  b4 b3  b2 b1  b0 b7  b6 b5  b4 b3  b2 b1  b0
b7  b6 b7  b6 b7  b6 b7  b6 b7  b6 b7  b6 b5  b4 b5  b4 b5  b4 b5  b4 b5  b4 b5  b4 b3  b2 b3  b2 b3  b2 b3  b2 b3  b2 b3  b2 b1  b0 b1  b0 b1  b0 b1  b0 b1  b0 b1  b0 b7  b6 b7  b6 b7  b6 b7  b6 b7  b6 b7  b6 b5  b4 b5  b4 b5  b4 b5  b4 b5  b4 b5  b4 b3  b2 b3  b2 b3  b2 b3  b2 b3  b2 b3  b2 b1  b0 b1  b0 b1  b0 b1  b0 b1  b0 b1  b0
(bytes)
MSB LSB MSB LSB
To scrambler
x x x x x x x x x x x x x x x x
(2 bits symbol) 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0
Symbol Symbol Symbol Symbol Symbol Symbol Symbol Symbol
SSSSSSyyyyyymmmmmmbolbolbolbolbolbol SSSSSSyyyyyymmmmmmbolbolbolbolbolbol SSSSSSyyyyyymmmmmmbolbolbolbolbolbol SSSSSSyyyyyymmmmmmbolbolbolbolbolbol SSSSSSyyyyyymmmmmmbolbolbolbolbolbol SSSSSSyyyyyymmmmmmbolbolbolbolbolbol SSSSSSyyyyyymmmmmmbolbolbolbolbolbol S S S S S Syyyyyymmmmmmbolbolbolbolbolbol
z  z+1  z+2  z+3  z+4  z+5  z+6  z+7
zzzzzz            z+1z+1z+1z+1z+1z+1            z+2z+2z+2z+2z+2z+2            z+3z+3z+3z+3z+3z+3            z+4z+4z+4z+4z+4z+4            z+5z+5z+5z+5z+5z+5            z+6z+6z+6z+6z+6z+6            z+7z+7z+7z+7z+7z+7
IEC  2511/03
Figure 17 – Byte to symbol conversion
In Figure 17, b7 is the most significant bit (MSB) of a byte, and b0 is the least significant bit
(LSB) of a byte. Therefore b7 of a byte is converted to x1 of a symbol.
6.9.1.3 Scramble
A scrambler is used for scrambling a symbol pattern for DQPSK to obtain spectrum shaping.
DQPSK is adopted to ensure enough binary transitions for clock recovery.
A scrambler consists of XOR gates as shown in Figure 18 and the scramble pattern
generator, which consists of a pseudo random binary sequence (PRBS) generator and a
counter, as shown in Figure 19.
x
y
from byte to
symbol
x :
i
converter q
1 to differential
y
1 :
encoder
x
from scramble
y
q :
i
pattern
generator
q
IEC  2512/03
Figure 18 – XOR gates
61603-8-1  IEC:2003 – 23 –
0 1 0 1 0 1 0 1 0 1 0 1 0 1
1 0 1
Load
Initialize
3 4 5 6 7 8 9 10 11 12 13 14 15 16
0 1 2
Transmission
clock
))
PRBS generator
))
q1
))
q0
MSB
Counter
0-7
IEC  2513/03
Enable
Figure 19 – Scramble pattern generator
The length of the PRBS is 17 bits and it is initialized at every chapter header. The polynomial
for the PRBS generator is
...