1、BRITISH STANDARD BS EN 61603-7:2003 Transmission systems for audio and/or video and related signals using infra-red radiation Part 7: Digital audio signals for conference and similar applications The European Standard EN 61603-7:2003 has the status of a British Standard ICS 33.160.99; 33.040.20 BS E
2、N 61603-7:2003 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 27 January 2005 BSI 27 January 2005 ISBN 0 580 45335 9 National foreword This British Standard is the official English language version of EN 61603-7:2003. It is identical with IE
3、C 61603-7:2003. It partially supersedes subclause 2.6.2 of BS EN 61603-3:1998. The UK participation in its preparation was entrusted to Technical Committee EPL/100, Audio, visual and multimedia systems and equipment, which has the responsibility to: A list of organizations represented on this commit
4、tee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Se
5、arch” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal
6、obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summ
7、ary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 27 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD E
8、N 61603-7 NORME EUROPENNE EUROPISCHE NORM October 2003 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2003 CENELEC - All rights
9、 of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61603-7:2003 E ICS 33.160.99; 33.040.20 Partly supersedes EN 61603-3:1998English version Transmission systems for audio and/or video and related signals using infra-red radiation Part 7: Digital audio s
10、ignals for conference and similar applications (IEC 61603-7:2003) Transmission de signaux audio et/ou vido et de signaux similaires au moyen du rayonnement infrarouge Partie 7: Systmes de transmissions numriques des signaux audio destins aux confrences et applications similaires (CEI 61603-7:2003) b
11、ertragung von Ton- und/oder Bildsignalen und verwandten Signalen mit Infrarot-Strahlung Teil 7: bertragungssysteme fr digitale Audiosignale fr Konferenzsysteme und hnliche Anwendungen (IEC 61603-7:2003) This European Standard was approved by CENELEC on 2003-10-01. CENELEC members are bound to comply
12、 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 Secre
13、tariat 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 t
14、he official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Lithuania, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and U
15、nited Kingdom. Foreword The text of document 100/649/FDIS, future edition 1 of IEC 61603-7, prepared by Technical Area 3, Infrared systems and applications, of IEC TC 100, Audio, video and multimedia systems and equipment, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
16、 EN 61603-7 on 2003-10-01. This European Standard supersedes 2.6.2 of EN 61603-3:1998. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2004-07-01 latest date by which the nati
17、onal standards conflicting with the EN have to be withdrawn (dow) 2006-10-01 Annexes designated “normative“ are part of the body of the standard. Annexes designated “informative“ are given for information only. In this standard, annexes A and ZA are normative and annexes B and C are informative. Ann
18、ex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 61603-7:2003 was approved by CENELEC as a European Standard without any modification. _ Page2 EN616037:2003CONTENTS 1 Scope.5 2 Normative references .5 3 Terms and definitions .5 4 Abbreviations .5 5 Exp
19、lanation of terms and general information .6 6 System considerations6 7 Basic system concept.6 8 Protocol7 9 Data protocol17 Annex A (normative) Definition of prototype filter .23 Annex B (informative) Example of /f diagram in the user area conference 24 Annex C (informative) Provision for future de
20、velopments .25 Annex ZA (normative) Normative references to international publications with their corresponding European publications .27 Figure 1 System.7 Figure 2 Conceptual model 7 Figure 3 Band allocation for 6 modulated sub-carriers8 Figure 4 (D)QPSK constellation and differential decoding algo
21、rithm.9 Figure 5 Pulse response of a raised cosine channel filter.10 Figure 6 Scrambler 11 Figure 7 Block diagram of sub-band APCM encoder 12 Figure 8 Quantization of sub-band samples .13 Figure 9 Superframe structure .14 Figure 10 RS frame structure.14 Figure 11 Audio block structure15 Figure 12 CR
22、C calculation .15 Figure 13 Audio block structure for medium quality16 Figure 14 Bit-pool sample structure for medium quality16 Figure 15 Audio block structure for high quality16 Figure 16 Bit-pool sample structure for high quality17 Figure 17 Positioning of the data protocol 18 Figure 18 Data messa
23、ge build-up.18 Figure 19 Configuration message structure19 Figure 20 Display message structure for ASCII display data 20 Figure 21 Display message structure for bitmap display data.21 Figure 22 Segmentation of data messages 21 Figure 23 Data packets fitted on to the superframe structure .22 Table 1
24、Sub-carrier centre frequencies 8 Table 2 Phase transitions of the differential encoding algorithm.9 Page3 EN616037:2003Table 3 Characteristics of sub-band APCM encoder.12 Table 4 Definition of audio mode bits .15 Table 5 Audio blocks and audio quality 17 Table 6 Data message identifier definition .1
25、8 Table 7 SCI definition 19 Table 8 Channel allocation table19 Table 9 Audio quality mode (AQM) to number of audio blocks used .20 Table C.1 Sub-carrier allocation.25 Page4 EN616037:2003 TRANSMISSION SYSTEMS OF AUDIO AND/OR VIDEO AND RELATED SIGNALS USING INFRA-RED RADIATION Part 7: Digital audio si
26、gnals for conference and similar applications 1 Scope This part of IEC 61603 describes the characteristics of a digital multiple channel, multiple carrier audio transmission system as an extension to conference interpretation or similar systems using the frequency ranges 45 kHz to 1 MHz and 2 MHz to
27、 6 MHz. NOTE These frequency ranges are also covered by analogue pulse systems used for the same applications. Interference is not expected because both transmission systems are normally not applied at the same time in the same room. 2 Normative references The following referenced documents are indi
28、spensable 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 61603-1:1997, Transmission of audio and/or video and related signals using infrared radi
29、ation Part 1: General IEC 61603-3:1997, Transmission of audio and/or video and related signals using infrared radiation Part 3: Transmission systems for audio signals for conference and similar systems IEC 61920, Infrared transmission systems Free air applications 1 ISO/IEC 7498-1:1994, Information
30、technology Open Systems Interconnection Basic Reference Model: The Basic Model 3 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 61603-1 apply. 4 Abbreviations APCM Adaptive pulse code modulation AQM Audio quality mode CAT Channel allocation table CM C
31、onfiguration message CRC Cyclic redundancy check DCI Display changed identifier DM Display message DM-CRC Data message CRC _ 1To be published. For the purposes of the reference in C.1, IEC 61920:1998 is equally valid. Page5 EN616037:2003DMI Data message identifier DML Data message length DQPSK Diffe
32、rential quadrature phase shift keying HQ High quality MAXCN Maximum channel number MHQ Mono high quality MMQ Mono medium quality MQ Medium quality OSI Open systems interconnection PCM Pulse code modulation PRBS Pseudo-random binary sequence SCI Source coding identifier SEI Setting changed identifier
33、 SF Scale factor SHQ Stereo high quality SMQ Stereo medium quality SRRC Square root raised cosine XOR Exclusive OR 5 Explanation of terms and general information For the purposes of this part of IEC 61603, the explanation and information given in IEC 61603-3, Clause 2, apply. 6 System considerations
34、 For the purposes of this part of IEC 61603, the considerations given in IEC 61603-3, Clause 3, apply. NOTE With regard to the primary band, the special caution advised in IEC 61603-3, 3.3 should be observed, especially for inductive lighting and future developments. 7 Basic system concept The basic
35、 system concept is shown in Figure 1. The system consists of a number (N) of audio sources, either analogue or digital, which are connected to a transmitter. The transmitter processes the audio signals (in accordance with the protocol described in Clause 8) into an electrical output to feed the infr
36、ared radiator. The infrared signal is received by the infrared receiver that processes the signal and outputs an audio signal and/or associated data. Page6 EN616037:2003Transmitter Infrared radiator Infrared receiver Audio source Audio source Audio source Audio source N sourcesFigure 1 System 8 Prot
37、ocol 8.1 System context In terms of the conceptual OSI reference model, the transmission protocol shall implement the following layers: Figure 2 Conceptual model Figure 2 shows the system context using the OSI reference model. Layers 1 and 2 will be part of the transmission protocol defined in this
38、standard. Data link layer (layer 2) I E C 6 1 6 0 3 - 7 IEC 61603-7 Physical layer (layer 1) IEC 61603-1 I E C 6 1 9 2 0 Audio streams User data (low rate, limited) Higher OSI protocol layers Higher OSI protocol layers Medium IEC 1548/03 IEC 1549/03 Page7 EN616037:20038.2 Physical layer 8.2.1 Genera
39、l OSI layer 1 (physical layer) shall use infrared radiation as the transfer medium between radiator and receiver as specified in IEC 61920 and IEC 61603-1. 8.2.2 Carrier Optical wavelength at the optical peak intensity P : 875 nm 25 nm 8.2.3 Sub-carriers Primary frequency band (band IV): 2 MHz 6 MHz
40、 Secondary frequency band (band II): 45 kHz 1 MHz. NOTE The secondary frequency band, 45 kHz to 1 MHz, is under consideration. Figure 3 shows the wideband allocation in the primary band, with the frequencies of each sub- carrier. A guard band between the transmission bands has been included. Table 1
41、 shows the frequencies of each sub-carrier. 2,333 3 3,667 4,333 5 5,667 f MHz GuardbandFigure 3 Band allocation for 6 modulated sub-carriers Table 1 Sub-carrier centre frequencies Sub-carrier Frequency kHz CC1 2333,333 CC2 3000 CC3 3666,667 CC4 4333,333 CC5 5000 CC6 5666,667 8.2.4 Occupied bandwidth
42、 The occupied bandwidth is defined as follows. ( ) + = 1 S occ r B where occ B is the occupied bandwidth; IEC 1550/03 Page8 EN616037:2003S r is the symbol rate ( = 2 b rfor (D)QPSK, r b is the bit rate (see 8.3); is the roll-off factor (see 8.2.6). 8.2.5 Sub-carrier modulation The modulation method
43、is (D)QPSK. The constellation is shown in Figure 4a. The differential decoding algorithm is shown in Figure 4b. The phase transitions for the differential encoding algorithm are also listed in Table 2. Figure 4 (D)QPSK constellation and differential decoding algorithm Table 2 Phase transitions of th
44、e differential encoding algorithm Phase change Symbol IQ 0 00 90 01 180 11 90 10 8.2.6 Filter characteristics A channel filter is included. A square root raised cosine (SRRC) characteristic, as illustrated in Figure 5, is implemented in both the transmitter and the receiver resulting in a total tran
45、sfer characteristic of a raised cosine. The roll-off factor of the filter is = 0,4. a) 11 01 00 10 I Qb) 10 00 01 11 00 10 01 11 11 11 11 00 00 00 10 10 10 01 01 01IEC 1551/03 Page9 EN616037:20030,2 0 0,2 0,4 0,6 0,8 1 0T b2 T b 3TbFigure 5 Pulse response of a raised cosine channel filter The combin
46、ed filter characteristic from the transmitting and receiving filter shall be in accordance with the following equation: + + + = ) ) ( 2 ( 2 ) ( 2 ) ( 2 cos ) ( 2 ) ( b b b b 2 b b b r 1 0 1 1 1 4 1 r f r f r r f T r f T f Pwhere ) ( r f P is the power transfer function; f is the frequency (Hz); b r
47、is the bit rate (bit/s); b b r T 1 = is the roll-off factor. 8.2.7 Channel coding 8.2.7.1 Reed-Solomon encoder A shorted Reed-Solomon encoder (n,k,d) = (28,24,5) on 8-bit symbols is used. The Reed- Solomon encoder operates in Galois Field GF(2 8 ). The field generator polynomial is: ( ) 1 2 + + + +
48、= x x x x x p 3 4 8IEC 1552/03 Page10 EN616037:2003The code generator polynomial is: () ( ) = + = 3 0 i i x x g 6 78 2 249 3 75 4 + + + + = x x x x = 02(HEX) 8.2.7.2 Scrambler The scrambler consists of an XOR gate and a pseudo-random binary sequence (PRBS) generator. The length of the PRBS is 11 bits and is initialized after every frame sync. The polynomial that is used for the PRBS is 1 + x 9+ x 11 and the initial pattern is Initial pattern = “10010101000” A diagram of the scrambler is shown in Figure 6. Scrambling is not applied to the frame
