IEC 621 04 Edition 3 0 201 5 07 INTERNATIONAL STANDARD Characteristics of DAB receivers IE C 6 2 1 0 4 2 0 1 5 0 7 (e n ) ® Copyright International Electrotechnical Commission THIS PUBLICATION IS COPY[.]
I E C 62 ® I N TE RN ATI ON AL S TAN D ARD IEC 621 04:201 5-07(en) C h aracteri s ti cs of D AB recei vers Edition 3.0 201 5-07 TH I S P U B L I C ATI O N I S C O P YRI G H T P RO TE C T E D C o p yri g h t © I E C , G e n e va , S w i tze rl a n d All rights reserved Unless otherwise specified, 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 either IEC or IEC's member National Committee in the country of the requester If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or your local IEC member National Committee for further information IEC Central Office 3, rue de Varembé CH-1 21 Geneva 20 Switzerland Tel.: +41 22 91 02 1 Fax: +41 22 91 03 00 info@iec.ch www.iec.ch Abou t th e I E C The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes International Standards for all electrical, electronic and related technologies Ab o u t I E C p u b l i c a ti o n s The technical content of IEC publications is kept under constant review by the IEC Please make sure that you have the latest edition, a corrigenda or an amendment might have been published I E C C atal og u e - webs tore i ec ch /catal og u e E l ectroped i a - www el ectroped i a org The stand-alone application for consulting the entire bibliographical information on IEC International Standards, Technical Specifications, Technical Reports and other documents Available for PC, Mac OS, Android Tablets and iPad The world's leading online dictionary of electronic and electrical terms containing more than 30 000 terms and definitions in English and French, with equivalent terms in additional languages Also known as the International Electrotechnical Vocabulary (IEV) online I E C pu bl i cati on s s earch - www i ec ch /s earch pu b I E C G l os s ary - s td i ec ch /g l os s ary The advanced search enables to find IEC publications by a variety of criteria (reference number, text, technical committee,…) It also gives information on projects, replaced and withdrawn publications More than 60 000 electrotechnical terminology entries in English and French extracted from the Terms and Definitions clause of IEC publications issued since 2002 Some entries have been collected from earlier publications of IEC TC 37, 77, 86 and CISPR I E C J u st P u bl i s h ed - webs tore i ec ch /j u s u bl i s h ed Stay up to date on all new IEC publications Just Published details all new publications released Available online and also once a month by email I E C C u s to m er S ervi ce C en tre - webs tore i ec ch /cs c If you wish to give us your feedback on this publication or need further assistance, please contact the Customer Service Centre: csc@iec.ch I E C 62 ® Edition 3.0 201 5-07 I N TE RN ATI ON AL S TAN D ARD C h aracteri s ti cs of D AB recei vers INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 33.060.20 ISBN 978-2-8322-281 2-8 Warn i n g ! M ake s u re th at you obtai n ed th i s pu bl i cati on from an au th ori zed d i s tri bu tor ® Registered trademark of the International Electrotechnical Commission –2– I EC 621 04:201 © I EC 201 CONTENTS FOREWORD Scope Normative references Terms and definitions Basic implementation and functional performance requirements Automatic mode selection 1 General Requirements Frequency bands Channel decoder 3.1 Standard receiver 3.2 Multimedia receiver 4 Service selection 4.1 General 4.2 Requirements 4 Receiver reactions to a multiplex reconfiguration 4 Audio decoder 4 6.1 General 4 6.2 DAB services 6.3 DAB + services Automatic switching to another ensemble Response to conditional access (CA) services 8.1 General 8.2 Requirements for DAB receivers without CA capabilities Output for audio and other services 9.1 General 9.2 Requirements Display 0.1 Standard receiver 0.2 Multimedia receiver 1 Text labels 1 Standard receiver 1 Multimedia receiver Data applications 2.1 Standard receiver 2.2 Multimedia receiver I nterfaces General RF input 2.1 General 2.2 Domestic and portable receivers 2.3 Automotive receivers Analogue audio interface (see I EC 61 938) Digital audio interface (see IEC 60958-3) Options General I EC 621 04:201 © I EC 201 –3– Service lists 6 Display 20 3.1 General 20 3.2 Service labels and service component labels 20 3.3 Dynamic label 20 3.4 Signal quality indicator 20 3.5 Audio coding information 20 Other receiver features 21 4.1 Time and date 21 4.2 Service following 21 4.3 Announcements 21 4.4 Dynamic range control (DRC) 21 Data features 21 5.1 Journaline 21 5.2 Broadcast website (BWS) 22 5.3 TPEG services 22 Minimum performance levels and measuring methods 22 General conditions 22 1 General – Published specifications for receivers 22 Power supply 22 Atmospheric conditions 22 BER measurement conditions 22 Acoustic onset of impairment (OOI) measurement conditions 23 DAB signal 23 7 Receiver classification 23 Audio part – Performance requirements 24 2.1 General 24 2.2 DAB services 24 2.3 DAB + services 24 RF part – Sensitivity test methods 24 3.1 General 24 3.2 Baseband stream and RF conditions for BER and OOI testing 24 3.3 Baseband stream and listening conditions for acoustic OOI testing 24 Sensitivity requirement using a conducted signal at node “A” 25 4.1 General 25 4.2 Method of measurement (Gaussian channel) using BER 25 4.3 Presentation of results using BER 25 4.4 Requirements – Receiver types A2, C2, D, E2 using BER 26 4.5 Method of measurement (Gaussian channel) using acoustic OOI 26 4.6 Presentation of results using acoustic OOI 26 4.7 Requirements – Receiver types A2, C2, D, E2 using acoustic OOI 26 Sensitivity using radiated electromagnetic wave at node "N" 27 5.1 General 27 5.2 Link budget transmission assumption – N on-automotive receivers 27 5.3 Method of measurement – N on-automotive types A1 , B, C1 C2 and A2 with optional antenna 27 5.4 Presentation of results 29 5.5 Requirements – Types A1 , B, C1 , C2 and A2 with optional antenna 29 5.6 Link budget transmission assumption – Automotive types D, E1 , E2 29 –4– I EC 621 04:201 © I EC 201 RF part – Maximum input power 29 7 6.1 General 29 6.2 Method of measurement (Gaussian channel) 29 6.3 Presentation of results 29 6.4 Requirements 29 7 RF part – Selectivity 30 7.1 General 30 7.2 Adjacent channel selectivity 30 7.3 Rejection of unwanted signals (far-off selectivity) 32 RF part – Performance in a Rayleigh channel 33 8.1 General 33 8.2 Sensitivity 33 8.3 Method of measurement – Conducted input signal only 33 8.4 Presentation of results 35 8.5 Requirements 35 RF part – Acquisition time after synchronization loss 35 9.1 General 35 9.2 Method of measurement 35 9.3 Presentation of results 36 9.4 Requirements 36 Annex A (informative) Recommended centre frequencies 37 Annex B (normative) Characteristics of a Rayleigh channel 39 B Simulation of the mobile radio channel 39 B Doppler spectrum types 39 B 2.1 General 39 B 2.2 Doppler spectrum: CLASS 40 B 2.3 Doppler spectrum: GAUS1 40 B 2.4 Doppler spectrum: GAUS2 40 B 2.5 Doppler spectrum: GAUSDAB 40 B 2.6 Doppler spectrum: RICE 40 B Propagation models 40 B 3.1 General 40 B 3.2 Typical rural (non-hilly) area (RA) 41 B 3.3 Typical urban (non-hilly) area (TU) 41 B Tap setting for hardware simulators 42 Annex C (informative) Basic characteristics and functionality for accessibility for blind and visually impaired users 44 Bibliography 45 Figure – Example of a functional block diagram of a DAB receiver Figure – Block diagram for the measurement of the sensitivity and the maximum input power, using BER 25 Figure – Block diagram for the measurement of the sensitivity and the maximum input power, using acoustic OOI 26 Figure – Block diagram for the measurement of free field sensitivity 27 Figure – Free field screened chamber measurement – Features and setup 28 Figure – Spectrum mask of the DAB signal for selectivity measurements 30 Figure – Block diagram for BER method selectivity measurements 31 I EC 621 04:201 © I EC 201 –5– Figure Figure Figure Figure Figure – Block diagram for OOI method selectivity measurements 32 – Block diagram for measuring the performance in a Rayleigh channel 34 – Block diagram for measuring acquisition time after synchronization loss 35 B.1 – Continuous delay power profile P( τ ) for RA 41 B.2 – Continuous delay power profile P( τ ) for TU 41 Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table – Performance requirement for an automotive active antenna – Classification of receiver types 23 – Conditions for BER and OOI testing 24 – Conditions for acoustic OOI testing 25 – Conditions for uniform signal level 28 – Minimum requirements for maximum input power (conducted) 30 – Difference between the centre frequencies of the DAB ensembles 31 – Minimum requirement for adjacent channel selectivity 32 – Channel simulation profiles related to frequency band and mode 34 A.1 – Recommended centre frequencies for DAB (1 of 2) 37 B.1 – Four tap setting for typical rural (non-hilly) area (RA) 42 B.2 – Six tap setting for typical rural (non-hilly) area (RA) 42 B.3 – Twelve tap setting for typical urban (non-hilly) area (TU) 43 B.4 – Six tap setting for typical urban (non-hilly) area (TU ) 43 B.5 – Tap setting for single-frequency networks (SFN) in VH F bands 43 –6– I EC 621 04:201 © I EC 201 I NTERNATIONAL ELECTROTECHNI CAL COMMI SSI ON C H ARAC T E RI S T I C S O F D AB RE C E I VE RS FOREWORD ) The I nternati onal El ectrotechnical Commi ssi on (I EC) is a worl d wi d e organizati on for stan dard izati on comprisi ng all nati onal electrotech nical committees (I EC N ational Comm ittees) Th e object of I EC is to promote i nternati on al co-operati on on al l q u esti ons cernin g standard izati on i n the el ectrical and el ectronic fi el ds To this end an d in ad di ti on to other acti vi ti es, I EC pu bli sh es I nternati onal Stand ards, Technical Speci fi cati ons, Technical Reports, Pu bl icl y Avail abl e Specificati ons (PAS) and Gui d es (hereafter referred to as “I EC Pu blicati on(s)”) Their preparati on is entru sted to technical committees; any I EC N ati onal Committee interested i n the subj ect d eal t with may parti ci pate i n thi s preparatory work I ntern ati on al , g overnmen tal and non governm ental organizations l iaisi ng wi th the I EC al so participate in th is preparati on I EC coll aborates cl osel y wi th th e I nternati on al Org anizati on for Stand ard ization (I SO) i n accordance wi th d i ti ons d etermined by agreement between th e two org anizati ons 2) Th e form al d ecision s or ag reements of I EC on technical matters express, as nearl y as possibl e, an i nternati onal consensus of opi ni on on the rel evant su bjects since each tech nical committee has representati on from all i nterested I EC N ati onal Commi ttees 3) I EC Pu blications have th e form of recommend ati ons for intern ati onal u se and are accepted by I EC N ati onal Comm ittees i n th at sense Whi le all reasonabl e efforts are mad e to ensu re that the techn ical content of I EC Pu blicati ons is accu rate, I EC cann ot be hel d responsi bl e for th e way i n wh i ch they are used or for an y misin terpretati on by any end u ser 4) I n ord er to promote i n ternational u ni formi ty, I EC N ati onal Commi ttees u nd ertake to appl y I EC Pu blicati ons transparen tl y to the maxi mum exten t possi bl e i n thei r nati onal and regi onal pu blicati ons Any di vergence between an y I EC Pu bl icati on and the correspond i ng nati onal or region al publi cation shal l be cl earl y i nd icated i n the l atter 5) I EC i tsel f does not provi d e any attestati on of conformity I nd epend ent certi ficati on bodies provi d e conformity assessment services an d , in some areas, access to I EC marks of conformi ty I EC i s not responsi bl e for an y services carried ou t by i nd epend en t certi fication bodi es 6) All users sh ould ensu re that they h ave the l atest edi ti on of this pu blicati on 7) N o li abili ty shal l attach to I EC or i ts di rectors, empl oyees, servants or agents i nclu di ng ind ivi du al experts and members of i ts tech ni cal comm ittees and I EC N ati on al Committees for an y personal inju ry, property d amag e or other d amage of any n atu re whatsoever, whether di rect or in d i rect, or for costs (i n cl u d i ng l egal fees) and expenses arising out of the pu blication, use of, or reli ance u pon, this I EC Pu bl ication or any other I EC Pu blicati ons 8) Attention is d rawn to the N ormative references ci ted i n this pu bl icati on U se of the referenced publicati ons is i ndi spensabl e for the correct appli cati on of this publicati on 9) Attention is d rawn to th e possibili ty that some of the elements of thi s I EC Pu bl icati on may be th e su bj ect of patent ri ghts I EC sh al l not be held responsi bl e for i d en ti fyi ng any or all su ch patent ri ghts I nternational Standard IEC 621 04 has been prepared by technical area , Terminals for audio, video and data services and contents, of I EC technical committee 00: Audio, video and multimedia systems and equipment This third edition cancels and replaces the second edition published in 2003 This edition constitutes a technical revision The main changes with respect to the previous edition are as follows • • The document has been updated in line with the development of the DAB system, and in particular the introduction of DAB + audio services (see ETSI TS 02 563) Requirements for displays, text and data applications have been introduced to reflect market trends _ For an overview of the DAB stand ards, see ETSI TR 01 495 I EC 621 04:201 â I EC 201 ã ã Additional test methods have been introduced to allow R.F measurements to be made on receivers with integrated antennas and/or no external BER indicators by using an acoustic impairment method Clause has been updated to reflect the development of the market and to provide better guidance for the implementation of optional features The text of this standard is based on the following documents: FDI S Report on voti ng 00/2502/FDI S 00/2541 /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 This publication has been drafted in accordance with the ISO/I EC Directives, Part The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the I EC website 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 A bilingual version of this publication may be issued at a later date –8– I EC 621 04:201 © I EC 201 C H ARAC T E RI S T I C S O F D AB RE C E I VE RS Scope This International Standard describes the digital audio broadcasting (DAB) receiver characteristics for consumer equipment intended for terrestrial and cable reception operating in VH F band I I I Dedicated receivers for specific applications are not within the scope of this standard This standard describes the characteristics for different classes and categories of DAB receivers such as standard and multimedia receivers and domestic, automotive and adapter receivers N o rm a t i v e re fe re n c e s The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies I EC 601 69-1 0, Radio-frequency connectors – Part 0: R F coaxial connectors with inner diameter of outer conductor mm (0, in) with snap-on coupling – Characteristic impedance 50 ohms (Type SMB) I EC 6031 5-1 , Methods of measurement on radio receivers for various classes of emission – Part : General considerations and methods of measurement, including audio-frequency measurements IEC 6031 5-4, Methods of measurement on radio receivers for various classes of emission – Part 4: Receivers for frequency-modulated sound-broadcasting emissions I EC 60958-3, Digital audio interface – Part 3: Consumer applications IEC 61 69-2: 2007, Radio-frequency connectors – Part 2: Sectional specification – Radio frequency coaxial connectors of type 9, 52 I EC 61 69-24, Radio-frequency connectors – Part 24: Sectional specification – Radio frequency coaxial connectors with screw coupling, typically for use in 75 ohm cable networks (type F) I EC 61 606 (all parts), A udio and audiovisual equipment – Digital audio parts – Basic measurement methods of audio characteristics I EC 61 938, Multimedia systems – Guide to the recommended characteristics of analogue interfaces to achieve interoperability I EC 621 06: 2009, Specification of the radio data system (RDS) broadcasting in the frequency range from 87, MHz to 08, MHz I SO/I EC 0646, for VHF/FM sound Information technology – Universal Coded Character Set (UCS) ISO/I EC 1 72-3, Information technology – Coding of moving pictures and associated audio for digital storage media at up to about , Mbit/s – Part 3: A udio – 34 – DAB baseband and RF signal generator Channel Simulator RF bandpass filter (if required) RF attenuator DAB receiver A I EC 621 04:201 © I EC 201 BER measurement E Data out RF power meter Controller IEC Key: The nu mbers i n th e corners refer to blocks Figure – Block diagram for measuring the performance in a Rayleigh channel The DAB signal generator is set to one of the centre frequencies given in Table and is modulated by a DAB encoder A channel simulator is inserted between the DAB signal generator and the variable attenuator This simulator shall be programmed through its controller with parameters corresponding to the channel profiles mentioned in Annex B An attenuator is foreseen at the output of the channel simulator A bandpass filter may also be necessary to filter out spurious signals Measurements shall be made in different bands (frequencies) and modes combined with different channel simulation profiles: urban, rural and SFN , according to Table Table includes urban and rural profiles referring to the profiles given in Annex B Table – Channel simulation profiles related to frequency band and mode M easu ring frequency MHz M ode Channel si mu lation profil es U rban at 25 km/h 225, 648 I Ru ral at 20 km/h SFN (VH F) at 60 km/h The measurement shall be performed in three steps a) The power level at the input of the DAB receiver shall be adjusted, using a selective power meter, in such a way that error-free reception is possible i.e BER ≤ –4 All synchronization conditions shall be met, including FIC, phase-reference and null-symbol capturing b) The input power to the receiver is reduced by increasing the variable attenuation During this process, care shall be taken that synchronization is not lost such as caused by attenuator switching transients) c) The BER measurement is observed or otherwise calculated i.e BER = 60 60 ∑ (No _ Bits _ in _ Error ) ÷ ∑ (Total _ No _ Bits _ Transmitted ) t =1 t =1 where t = time in seconds I t should be confirmed that the BER has been better than the specified value –4 for a specified measuring time of I f this is so, the receiver is qualified for this power level, and the procedure goes back to repeat the second and third phase, to measure the next lower power level I EC 621 04:201 © I EC 201 – 35 – When the receiver fails to maintain the specified BER of –4 , the procedure stops and the previous value of input power, at which the BER is less than –4 , is taken as the result 8.4 Presen tation of resu lts The result of this measurement is presented as the lowest power level in dBm at which the receiver is still able to maintain a BER of –4 during a one minute observation period, and this for each defined channel simulation profile 8.5 Requ i remen ts The minimum requirement is dependent upon the tuning frequency band, as follows: Minimum requirement: –92,2 dBm VHF band RF part – Acqu i siti on ti me after syn ch ron ization loss 9.1 G en eral The time of audio mute between switching off the received ensemble and re-synchronizing to the same ensemble at an offset frequency is defined as the acquisition time after synchronization loss 9.2 M eth od of m easu remen t Figure shows the block diagram of the measurement set-up Baseband encoder -1 RF signal generator - f1 A Baseband encoder -2 Key: RF signal f2 generator -2 DAB receiver J, K, L Audio out Audio mute detection RF path switch IEC The nu mbers i n th e corners refer to blocks Fi gu re – Block d iag ram for m easu ri n g acq u i siti on ti me after syn ch ron ization loss The DAB signal should be according to 7.1 The frequency f2 of RF signal generator shall have an offset to frequency f1 of RF signal generator of half a carrier spacing, according to the appropriate DAB transmission mode (500 Hz in the case of mode I , ETSI EN 300 401 ) First the signal of RF signal generator is supplied to the RF receiver After a switch-off time of at least s the signal of RF signal generator is supplied to the DAB receiver and the time it takes for the DAB receiver to resynchronize is measured with the mute detection circuit Measurements shall be made five times, separately for all supported DAB transmission modes The result is the average value of the measurements – 36 – I EC 621 04:201 © I EC 201 For DAB receivers without any audio capability, the measurements shall be conducted by monitoring valid data at the output of the channel decoder 9.3 Presentation of resu lts The acquisition time is expressed in milliseconds and presented separately for each supported transmission mode 9.4 Requ irements Minimum requirement: < 000 ms for a switch-off time > s I EC 621 04:201 © I EC 201 – 37 – Annex A (informative) Recommended centre frequencies Table A.1 shows the recommended centre frequencies for DAB Table A.1 – Recommended centre frequencies for DAB (1 of 2) T-DAB block Number T-DAB block Label a Centre frequency Lower limit U pper limit MHz MHz MHz 13 5A 74, 928 74, 60 75, 696 14 5B 76, 640 75, 872 77, 408 15 5C 78, 352 77, 584 79, 20 16 5D 80, 064 79, 296 80, 832 17 6A 81 , 936 81 , 68 82, 704 18 6B 83, 648 82, 880 84, 41 19 6C 85, 360 84, 592 86, 28 20 6D 87, 072 86, 304 87, 840 21 7A 88, 928 88, 60 89, 696 22 7B 90, 640 89, 872 91 , 408 23 7C 92, 352 91 , 584 93, 20 24 7D 94, 064 93, 296 94, 832 25 8A 95, 936 95, 68 96, 704 26 8B 97, 648 96, 880 98, 41 27 8C 99, 360 98, 592 200, 28 28 8D 201 , 072 200, 304 201 , 840 29 9A 202, 928 202, 60 203, 696 30 9B 204, 640 203, 872 205, 408 31 9C 206, 352 205, 584 207, 20 32 9D 208, 064 207, 296 208, 832 33 0A 209, 936 209, 68 21 0, 704 See N OTE 0N 21 0, 096 209, 328 21 0, 864 34 0B 21 , 648 21 0, 880 21 2, 41 35 0C 21 3, 360 21 2, 592 21 4, 28 36 0D 21 5, 072 21 4, 304 21 5, 840 37 11A 21 6, 928 21 6, 60 21 7, 696 See N OTE 11N 21 7, 088 21 6, 320 21 7, 856 38 11B 21 8, 640 21 7, 872 21 9, 408 – 38 – Table A.1 I EC 621 04:201 © I EC 201 (2 of 2) T-DAB block Number T-DAB block Label a Centre frequency Lower limit U pper limit MHz MHz MHz 39 11C 220, 352 21 9, 584 221 , 20 40 11D 222, 064 221 , 296 222, 832 41 2A 223, 936 223, 68 224, 704 See N OTE 2N 224, 096 223, 328 224, 864 42 2B 225, 648 224, 880 226, 41 43 2C 227, 360 226, 592 228, 28 44 2D 229, 072 228, 304 229, 840 45 3A 230, 784 230, 01 231 , 552 46 3B 232, 496 231 , 728 233, 264 47 3C 234, 208 233, 440 234, 976 48 3D 235, 776 235, 008 236, 544 49 3E 237, 488 236, 720 238, 256 50 3F 239, 200 238, 432 239, 968 N OTE This tabl e tai ns a u nified l abell ing system for all th e DAB freq u ency bl ocks i n Eu rope N OTE To avoi d temporary com patibi lity probl ems wi th other services in some cou ntri es i n excepti onal cases, i t coul d be n ecessary to shi ft the transmi tted centre frequ ency a few times kH z Ded icated receivers wi ll compl y N OTE The tabl e is ful l y compati bl e wi th the existi ng VH F television chann el n umbers for Stan d ard Eu rope B, C (i e channels E5 to E1 and the so-cal led channel 3, which correspond s to a freq u ency rang e from 230 M H z to 240 M H z) N OTE All the freq u enci es listed in th e table com pl y wi th th e kH z raster as speci fi ed i n ETSI EN 300 401 N OTE Offsets to bl ocks 0A, 1 A an d 2A wi ll all ow these bl ocks to be u sed i n areas al so covered by B/PAL/N I CAM tel evi si on transmi tters operatin g i n the l ower ad j acent channels The televisi on transmitters al so need to be offset d own ward s in freq uen cy by the maxi mu m all owabl e amou n t (approxi matel y 200 kH z) The three ad d iti onal centre freq u enci es are: – 21 0, 096 M H z (1 N ); – 21 7, 088 M H z (1 N ); – 224, 096 M H z (1 N ) a Freq u ency bl ock l abel s consist of two or three characters, whi ch m ay be conveni en t for receiver manu factu rers and consu mers for i niti al programming of thei r receivers I EC 621 04:201 © I EC 201 – 39 – Annex B (normative) Characteristics of a Rayleigh channel N OTE Th is annex d escri bes th e setti ngs of a chann el simu lator accord ing to Figu re B.1 Simulation of the mobile radio channel The mobile radio channel is described by highly dispersive multi-path propagation caused by reflection and scattering The paths between transmitter and mobile receiver can be considered to consist of large reflectors and/or scatterers at some distance to the mobile, giving rise to a number of waves that arrive in the vicinity of the mobile with random amplitudes and delays Close to the mobile, these paths are further randomized by local reflections/diffractions For a moving mobile, the angle of incidence of the received signal at the antenna shall also be taken into account, since it affects the Doppler shift associated with a wave arriving from a particular direction Propagation models for the description of the above mobile radio channel have been defined in order to allow practical simulation by means of a hardware simulator They comprise echo profiles covering the specific reception conditions in conventional networks as well as in single- frequency networks (SFN ) The propagation models are presented below in terms of the time delay, amplitude coefficient and the Doppler spectra associated with each delay path: a) a discrete number of taps, each determined by its time delay and its average power; b) the Rayleigh distributed amplitude of each tap, varying according to a Doppler spectrum S (τ i , f ) , where i is the tap index B.2 Doppler spectrum types B.2.1 General For the modelling of the channel, five types of Doppler spectra are defined They describe the relation of power density versus Doppler shift, i e the influence of the speed of the moving car and the impacts of the surrounding terrain The following abbreviations are used: – fd = v λ represents the maximum Doppler shift, with vehicle speed v [m/s] and wavelength [m] G ( A, f1 , f2 ) is the Gaussian function: λ – G (magnitude, Doppler shift, standard deviation of Gaussian distribution) ( f − f1 )2 f2 G ( f ) = A exp The defined spectrum types are described in subclauses B.2 to B – 40 – B.2.2 D o p p l e r s p e c t ru m : I EC 621 04:201 © I EC 201 C L AS S CLASS is the classical Doppler spectrum and is to be used for paths with delays up to 0, µ s, ( τ i ≤ 0, µ s) S (τ i , f ) = (CLASS) B.2.3 D o p p l e r s p e c t ru m : A − f f d for f ∈ ]− fd , fd [ G AU S GAU S1 is the sum of two Gaussian functions and is used for excess delay times in the range of 0,5 µ s to µ s, (0, µ s ≤ τ i ≤ µ s) S( τ i , f) = G ( A , –0,8 fd , 0,05 fd ) + G ( A , + 0, fd , 0,1 fd ) (GAU S1 ) where A is dB below A B.2.4 D o p p l e r s p e c t ru m : G AU S GAU S2 is also the sum of two Gaussian functions and is used for paths with delays in excess of µ s, ( τ i > µ s) S( τ i , f) = G ( B , + 0, fd , 0,1 fd ) + G ( B , –0,4 fd , 0,1 fd ) (GAU S2) where B is dB below B B.2.5 D o p p l e r s p e c t ru m : G AU S D AB GAU SDAB is composed of a Gaussian function and is used for special DAB profiles (GAU SDAB) S( τ i , f) = G ( A , ± 0, fd , 0,1 fd ) where + 0, fd applies to even path numbers and –0,7 fd for odd, except path B.2.6 D o p p l e r s p e c t ru m : RI C E RI CE is the sum of a classical Doppler spectrum and one direct path, so that the total multipath contribution is equal to that of the direct path This spectrum is used for the shortest path of the model for propagation in rural areas S (τ i , f ) = (RICE) 0, 41 πfd − f f d + 0,91 d ( f − 0,7 fd ) for f ∈ ]− fd , fd [ B.3 B.3.1 P ro p a g a t i o n mod el s G e n e l The multi-path propagation model is based on a transversal filter structure, each tap representing a signal path associated with a certain delay and modulated by the appropriate Doppler spectrum I EC 621 04:201 © I EC 201 – 41 – Continuous delay power profiles for different types of terrain are specified to describe the models These continuous profiles are approximated by the discrete parameter settings of hardware fading simulators according to Clause B The continuous delay power profiles P( τ ) are defined in B 3.2 and B.3 Typical rural (non-hilly) area (RA) P dB B.3.2 –1 –20 –30 τ µs IEC Figure B.1 – Continuous delay power profile P( τ ) for RA exp (− τ τ m ) P(τ ) = 0 τm = 0,1 08 µ s Typical urban (non-hilly) area (TU) P dB B.3.3 for < τ < 0,7 elsewhere –1 –20 –30 τ µs IEC Figure B.2 – Continuous delay power profile P( τ ) for TU exp (− τ τ m ) P(τ ) = 0 τm for < τ < elsewhere = µs – 42 – B I EC 621 04:201 © I EC 201 Tap settin g for h ardware si m u lators Hardware multi-tap fading simulators use the propagation model described in Clause B.3 They are equipped with a finite number of taps (3 to taps) which can be set to discrete values of S ( τ i ) in both amplitude and delay Further, the assignment of a particular Doppler spectrum to each path is possible to simulate the mobile channel, i.e the moving receiver The Doppler spectrum requires for complete definition the maximum Doppler shift This can be chosen directly at the simulator or by selecting the centre frequency and driving speed The tap setting below is given for simulators comprising up to taps and for simulators with reduced model settings up to taps The delay spread mentioned in the tables below is defined by the equation: SD2 = I 1 I τ i P(τ i ) − τ P(τ ) Pm ∑ P ∑ i i i =1 m i =1 where I is the total number of taps and Pm I = ∑ P(τ i ) is the total transmitted power i =1 Tap settings are shown in Table B , Table B.2, Table B.3, Table B.4 and Table B.5 Tabl e B.1 – Fou r tap setti n g for typi cal ru ral (n on -h i ll y) area (RA) Tap Del ay Power Power Doppl er SD No µs l i n ear dB categ ory µs 1 RI CE 0, 0, 63 –2 CLASS 0, 0, –1 CLASS 0, 0, 01 –20 CLASS 0, ± 0, 02 Tabl e B – Si x tap setti n g for typi cal ru ral (n on -h i l l y) area (RA) Tap Del ay Power Power Doppl er SD No µs l i n ear dB categ ory µs 1 RI CE 0, 0, –4 CLASS 0, 0, –8 CLASS 0, 0, 06 –1 CLASS 0, 0, 03 –1 CLASS 0, 0, 01 –20 CLASS 0, ± 0, 02 I EC 621 04:201 © I EC 201 – 43 – Table B.3 – Twelve tap settin g for typical urban (n on-h il ly) area (TU ) Tap Del ay Power Power Doppl er SD No µs l i n ear dB categ ory µs 0, –4 CLASS 0, 0, –3 CLASS 0, CLASS 0, 0, 55 –2, CLASS 0, 0, –3 GAU S1 ,1 0, 32 –5 GAU S1 ,3 –7 GAU S1 ,7 0, 32 –5 GAU S1 2, 0, 22 –6, GAU S2 10 3, 0, –8, GAU S2 11 3, 0, 08 –1 GAU S2 12 5, 0, –1 GAU S2 ,0 ± 0, Tabl e B.4 – Six tap settin g for typi cal urban (non-h ill y) area (TU ) Tap Del ay Power Power Doppl er SD No µs l i n ear dB categ ory µs 0, –3 CLASS 0, CLASS 0, 0, 63 –2 CLASS ,6 0, 25 –6 GAU S1 2, 0, –8 GAU S2 5, 0, –1 GAU S2 ,0 ± Table B.5 – Tap setting for si ng le-frequ ency networks (SFN ) in VH F bands Tap Del ay Power Power Doppl er SD No µs l i n ear dB categ ory µs 0, 93 CLASS 00 0, 046 −1 GAU SDAB 220 0, 01 −1 GAU SDAB 290 6×1 0−3 − 22 GAU SDAB 385 3×1 0−3 − 26 GAU SDAB 480 8×1 0−4 − 31 GAU SDAB 600 6×1 0−4 − 32 GAU SDAB 0, – 44 – I EC 621 04:201 © I EC 201 Annex C (informative) Basic characteristics and functionality for accessibility for blind and visually impaired users A digital radio device shall support speech output for all configuration functions This applies for menus as well as for service selection Service label and additional textual information shall be output as audio, e g using a build-in text-to-speech engine The beginning or end of scrollable lists should be acoustically indicated For frequently-used functions (like volume, bass, treble) explicitly assigned tactile use elements shall be available N umeric buttons for selection of channels or station storage are very useful Multiple functional assignments to buttons should be avoided or, if this is not possible, different usage levels of the same buttons shall be signalled by acoustic hints (tones or speech output) All buttons should easily be identifiable by their form and/or location The manual and supporting documentation for a digital radio device shall be available as audio or in braille Digital radio data services should be made available to the listener as much as possible For example, dynamic label information could be read out through a built-in text-to-speech engine Journaline as the advanced text service for digital radio explicitly supports hinting information for an improved text-to-speech conversion, including options for phonemic metadata descriptions (based on the I PA standard), pause indications, a macro function to insert repeating information, e.g to make tables usable, and general language indications for whole text pages and individual sections This functionality can be used for speech output in cars as well as for blind or visually disabled persons Additional information is available from various organisations that support accessibility, for example: http: //www rnib org uk/sites/default/files/video_transcript_Making_digital_radios_more_usable doc I EC 621 04:201 © I EC 201 – 45 – Bibliography I EC 60068-1 , Environmental testing – Part : General and guidance I EC 60721 (all parts), IEC Guide 06, Classification of environmental conditions Guide for specifying environmental conditions for equipment performance rating CI SPR 3, Sound and television broadcast receivers and associated equipment – Radio disturbance characteristcs – Limits and methods of measurement CI SPR 20, Sound and television broadcast receivers and associated equipment – Immunity characteristics – Limits and methods of measurement I SO/I EC 1 72-4, Information technology – Coding of moving pictures and associated audio for digital storage media at up to about , Mbit/s – Part 4: Compliance testing I SO/I EC 381 8-4, Information technology – Part 4: Generic coding of moving pictures and associated audio information – Conformance testing I TU -T Recommendation O 51 , Error performance measuring equipment operating at the primary rate and above ETSI TR 01 495, Digital A udio Broadcasting (DA B) ; Guide to DA B standards; Guidelines and Bibliography _ I N TE RN ATI O N AL E LE CTRO TE CH N I CAL CO M M I S S I O N 3, ru e d e Va re m bé P O B ox CH -1 1 G e n e va S wi tze rl a n d Te l : + 41 F a x: + 22 91 02 1 22 91 03 00 i n fo @i e c ch www i e c ch