EN 301 926 V1.1.1 (2001-09) European Standard (Telecommunications Series)

Total Page:16

File Type:pdf, Size:1020Kb

EN 301 926 V1.1.1 (2001-09) European Standard (Telecommunications Series) Draft ETSI EN 301 926 V1.1.1 (2001-09) European Standard (Telecommunications series) Satellites Earth Stations and Systems (SES); Radio Frequency and Modulation Standard for Telemetry, Command and Ranging (TCR) of Geostationary Communications Satellites 2 Draft ETSI EN 301 926 V1.1.1 (2001-09) Reference DEN/SES-000-ECSS-1 Keywords control, modulation, satellite, telemetry ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N° 348 623 562 00017 - NAF 742 C Association à but non lucratif enregistrée à la Sous-Préfecture de Grasse (06) N° 7803/88 Important notice Individual copies of the present document can be downloaded from: http://www.etsi.org The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the current status of this and other ETSI documents is available at http://www.etsi.org/tb/status/ If you find errors in the present document, send your comment to: [email protected] Copyright Notification No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. © European Telecommunications Standards Institute 2001. All rights reserved. ETSI 3 Draft ETSI EN 301 926 V1.1.1 (2001-09) Contents Intellectual Property Rights................................................................................................................................5 Foreword.............................................................................................................................................................5 1 Scope ........................................................................................................................................................6 2 References ................................................................................................................................................6 3 Definitions and abbreviations...................................................................................................................6 3.1 Definitions..........................................................................................................................................................6 3.2 Abbreviations .....................................................................................................................................................8 4 Applicability.............................................................................................................................................9 5 Modulation Requirements ......................................................................................................................10 5.1 General .............................................................................................................................................................10 5.2 Standard modulation.........................................................................................................................................11 5.2.1 Modulating waveforms...............................................................................................................................11 5.2.2 PCM waveforms and symbol rates .............................................................................................................11 5.2.3 Use of subcarriers .......................................................................................................................................11 5.2.4 Choice of Subcarrier Frequencies...............................................................................................................11 5.2.5 Uplink carrier deviation (Frequency Modulation) ......................................................................................12 5.2.6 Downlink PM modulation index.................................................................................................................12 5.2.7 PM sense of modulation .............................................................................................................................13 5.3 Spread Spectrum Modulation...........................................................................................................................13 5.3.1 Chip shaping ...............................................................................................................................................15 5.4 Coherency properties........................................................................................................................................15 5.4.1 FEC Channel Coding..................................................................................................................................15 6 Requirements on transmitted signals......................................................................................................15 6.1 Frequency stability requirements .....................................................................................................................15 6.1.1 Uplink .........................................................................................................................................................15 6.1.2 Downlink ....................................................................................................................................................16 6.2 Turnaround frequency ratio..............................................................................................................................16 6.3 Polarization.......................................................................................................................................................16 6.4 Phase noise .......................................................................................................................................................16 7 Link Acquisition requirements...............................................................................................................16 Annex A (informative): Operational configuration.....................................................................................17 A.1 Configuration 1: on board dual mode receiver and on board dual mode transmitter.............................18 A.2 Configuration 2: on board dual mode receiver and Standard transmitter...............................................19 A.3 Configuration 3: on board dual mode receiver, Standard transmitter and dedicated RG SS transmitter...............................................................................................................................................20 Annex B (informative): Hybrid Ranging process description....................................................................22 B.1 Presentation ............................................................................................................................................22 B.2 Distance ambiguity resolution................................................................................................................23 B.3 Calibration..............................................................................................................................................24 Annex C (informative): Modulator imperfections.......................................................................................25 C.1 Phase imbalance .....................................................................................................................................25 C.2 BPSK phase imbalance ..........................................................................................................................25 C.3 QPSK phase imbalance ..........................................................................................................................25 ETSI 4 Draft ETSI EN 301 926 V1.1.1 (2001-09) C.4 Amplitude imbalance .............................................................................................................................25 C.5 Data asymmetry......................................................................................................................................26 C.6 Data bit jitter...........................................................................................................................................26 C.7 PN code asymmetry................................................................................................................................26 C.8 PN code chip jitter..................................................................................................................................26 C.9 Chip Transition Time .............................................................................................................................26 C.10 I/Q Data Bit Skew ..................................................................................................................................27 C.11 I/Q PN Code Chip Skew ........................................................................................................................27 Annex D (informative): SRRC
Recommended publications
  • “Thank You” to Your Service Customers with FREE SIRIUSXM
    Say “thank you” to your service customers with FREE SIRIUSXM. Give them whatever they want to hear, whenever they want to hear it. Over 17,000 participating Dealers have already signed up. Your customers can receive a free 2-month trial subscription*† to our best package when they bring in their factory-equipped vehicles for service. The All Access trial subscription New Vehicles includes the widest variety of entertainment available in a car. Plus, they can enjoy SiriusXM on their phone and online, where they can create their own Certified Pre-Owned ad-free Personalized Stations Powered by Pandora, hear over 100 ad-free Xtra channels of music, watch SiriusXM video, and more. It’s all included in their trial and it’s at no cost to you or your customers. SXM Pre-Owned Program This exciting program is an easy way to augment your Service Customer Loyalty programs and show your customers your gratitude for choosing your Service Lane Program shop. Join today and we’ll notify your qualifying customers of their trial so they can start enjoying SiriusXM. PROGRAM BENEFITS Complimentary 2-Month Trial Subscription*† to the SiriusXM All Access package with over 150 channels of ad-free music, plus sports, news, talk and entertainment — no strings attached No cost to you or to your customer No Dealer effort required to activate the trial for Service customers HOW IT WORKS Join the free Service Simple one-time dealership opt-in process Lane Program today at Once SiriusXM receives your Service data, we will notify your eligible SiriusXMDealerPrograms.com customers of their trial, courtesy of your dealership and SiriusXM Same great programming for even more customers No dealer effort required to promote program or activate trials for Service customers MONTH Sign up and we will do the rest.
    [Show full text]
  • China's Power Sector Heads Towards a Cleaner Future
    EMBARGOED TO 10AM Beijing Time, 27 AUGUST 2013 CONTACT (China) Jun Ying, Bloomberg New Energy Finance +86 10 6649 7522 [email protected] CHINA’S POWER SECTOR HEADS TOWARDS A CLEANER FUTURE China’s power capacity will more than double by 2030 and renewables including large hydro will account for more than half of new plants, eroding coal’s dominant share and attracting investment of $1.4 trillion. China’s power sector carbon emissions could be in decline by 2027. Beijing, 27 August 2013 – China’s power sector is expected to go through significant changes through to 2030, according to a new report released by Bloomberg New Energy Finance. China will add 88GW of new power plants annually from now until 2030, which is equivalent to building the UK’s total generating capacity every year. China is already the world’s largest power generator and its largest carbon emitter. Over the next two decades China could add more than 1,500GW of new generating capacity and invest more than $3.9 trillion in power sector assets. However, as a result of shifts in generation mix, China’s total power sector emissions could start declining as early as 2027. Bloomberg New Energy Finance analysed China’s power sector based on four scenarios. In the central scenario, dubbed ‘New Normal’, China’s total power generation capacity more than doubles by 2030, with renewables including large hydro contributing more than half of all new capacity additions. This, together with an increase in gas-based generation, would drive the share of coal-fired power generation capacity down from 67% in 2012 to 44% in 2030.
    [Show full text]
  • Digital Audio Broadcasting : Principles and Applications of Digital Radio
    Digital Audio Broadcasting Principles and Applications of Digital Radio Second Edition Edited by WOLFGANG HOEG Berlin, Germany and THOMAS LAUTERBACH University of Applied Sciences, Nuernberg, Germany Digital Audio Broadcasting Digital Audio Broadcasting Principles and Applications of Digital Radio Second Edition Edited by WOLFGANG HOEG Berlin, Germany and THOMAS LAUTERBACH University of Applied Sciences, Nuernberg, Germany Copyright ß 2003 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England Telephone (þ44) 1243 779777 Email (for orders and customer service enquiries): [email protected] Visit our Home Page on www.wileyeurope.com or www.wiley.com All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except under the terms of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London W1T 4LP, UK, without the permission in writing of the Publisher. Requests to the Publisher should be addressed to the Permissions Department, John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England, or emailed to [email protected], or faxed to (þ44) 1243 770571. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the Publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought.
    [Show full text]
  • ABBREVIATIONS EBU Technical Review
    ABBREVIATIONS EBU Technical Review AbbreviationsLast updated: January 2012 720i 720 lines, interlaced scan ACATS Advisory Committee on Advanced Television 720p/50 High-definition progressively-scanned TV format Systems (USA) of 1280 x 720 pixels at 50 frames per second ACELP (MPEG-4) A Code-Excited Linear Prediction 1080i/25 High-definition interlaced TV format of ACK ACKnowledgement 1920 x 1080 pixels at 25 frames per second, i.e. ACLR Adjacent Channel Leakage Ratio 50 fields (half frames) every second ACM Adaptive Coding and Modulation 1080p/25 High-definition progressively-scanned TV format ACS Adjacent Channel Selectivity of 1920 x 1080 pixels at 25 frames per second ACT Association of Commercial Television in 1080p/50 High-definition progressively-scanned TV format Europe of 1920 x 1080 pixels at 50 frames per second http://www.acte.be 1080p/60 High-definition progressively-scanned TV format ACTS Advanced Communications Technologies and of 1920 x 1080 pixels at 60 frames per second Services AD Analogue-to-Digital AD Anno Domini (after the birth of Jesus of Nazareth) 21CN BT’s 21st Century Network AD Approved Document 2k COFDM transmission mode with around 2000 AD Audio Description carriers ADC Analogue-to-Digital Converter 3DTV 3-Dimension Television ADIP ADress In Pre-groove 3G 3rd Generation mobile communications ADM (ATM) Add/Drop Multiplexer 4G 4th Generation mobile communications ADPCM Adaptive Differential Pulse Code Modulation 3GPP 3rd Generation Partnership Project ADR Automatic Dialogue Replacement 3GPP2 3rd Generation Partnership
    [Show full text]
  • Implementation Considerations for the Introduction and Transition to Digital Terrestrial Sound and Multimedia Broadcasting
    Report ITU-R BS.2384-0 (07/2015) Implementation considerations for the introduction and transition to digital terrestrial sound and multimedia broadcasting BS Series Broadcasting service (sound) ii Rep. ITU-R BS.2384-0 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio- frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http://www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found. Series of ITU-R Reports (Also available online at http://www.itu.int/publ/R-REP/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management Note: This ITU-R Report was approved in English by the Study Group under the procedure detailed in Resolution ITU-R 1.
    [Show full text]
  • Request for Proposal for Satellite Radio Programming Services Pursuant to FCC Qualified Entity Set-Aside
    Request for Proposal for Satellite Radio Programming Services Pursuant to FCC Qualified Entity Set-Aside Issued March 25, 2021 - Deadline to Respond - April 25, 2021, 11:59 pm Eastern Time Sirius XM Radio Inc. Qualified Entity RFP, March 25, 2021 I. INTRODUCTION Sirius XM Radio Inc. (“Sirius XM,” “we,” or “us”) invites interested and qualified parties (the “Proposer” or “you”) to participate in this Request for Proposal (“RFP”) process for providing satellite radio programming that we will carry on satellite radio channels pursuant to the Qualified Entity set-aside required by the Federal Communications Commission (“FCC”). Company Background Sirius XM is America’s satellite radio company. We deliver over 130 channels of audio entertainment, including commercial-free music, premier sports, news, talk, entertainment, traffic and weather, to more than 34 million customers. SiriusXM’s satellite and streaming audio platform is the home of Howard Stern's two exclusive channels. Its ad-free, curated music channels represent many decades and genres, from rock, to pop, country, hip hop, classical, Latin, electronic dance, jazz, heavy metal and more. SiriusXM's programming includes news from respected national outlets, and a broad range of in- depth talk, comedy and entertainment. For sports fans, SiriusXM also offers live games, events, news, analysis and opinion for all major professional sports, fulltime channels for top college sports conferences, and programming that covers other sports such as auto sports, golf, soccer, and more. SiriusXM is also the home of exclusive and popular podcasts including many original SiriusXM series and a highly-curated selection of podcasts from leading creators and providers.
    [Show full text]
  • AN1597 Longwave Radio Data Decoding Using an HC11 and an MC3371
    Freescale Semiconductor, Inc... microprocessor used for decoding is the MC68HC(7)11 while microprocessor usedfordecodingisthe MC68HC(7)11 2023. and 1995 between distinguish Itisnotpossible to 2022. and thiscanbeusedtocalculate ayearintherange1995to beworked out cyclecan,however, leap–year/year–start–day data.Thepositioninthe28–year available andcannotbeuniquelydeterminedfromthe transmitted and yeartype)intoday–of–monthmonth.Theisnot dateinformation(day–of–week,weeknumber transmitted the form.Themicroprocessorconverts hexadecimal displayed whilst allincomingdatacanbedisplayedin In thisapplication,timeanddatecanbepermanently standards. Localtimevariation(e.g.BST)isalsotransmitted. provides averyaccurateclock,traceabletonational Freescale AMCU ApplicationsEngineering Topping Prepared by:P. This documentcontains informationonaproductunder development. This to thecompanyleasingitforuseinaspecificapplication. available blocks areusedcommerciallywhereeachblockis other 0isusedfortimeanddate(andfillerdata)whilethe Type purpose.There are16datablocktypes. used foradifferent countriesbuthasamuchlowerdatarateandis European with theRDSdataincludedinVHFradiosignalsmany aswelltheaudiosignal.Thishassomesimilarities data using an HC11 and Longwave an Radio MC3371 Data Decoding Figure 1showsablock diagramoftheapplication; Figure data is transmitted every minuteontheand Time The BBC’s Radio4198kHzLongwave transmittercarries The BBC’s Ltd.,EastKilbride RF AMPLIFIERDEMODULATOR FM BF199 FILTER/INT.: LM358 FILTER/INT.: AMP/DEMOD.: MC3371 LOCAL OSC.:MC74HC4060
    [Show full text]
  • Subcarrier Intensity Modulated Free-Space Optical Communication Systems
    SUBCARRIER INTENSITY MODULATED FREE-SPACE OPTICAL COMMUNICATION SYSTEMS WASIU OYEWOLE POPOOLA A thesis submitted in partial fulfilment of the requirements of the University of Northumbria at Newcastle for the degree of Doctor of Philosophy Research undertaken in the School of Computing, Engineering and Information Sciences September 2009 Abstract This thesis investigates and analyses the performance of terrestrial free-space optical communication (FSO) system based on the phase shift keying pre-modulated subcarrier intensity modulation (SIM). The results are theoretically and experimentally compared with the classical On-Off keying (OOK) modulated FSO system in the presence of atmospheric turbulence. The performance analysis is based on the bit error rate (BER) and outage probability metrics. Optical signal traversing the atmospheric channel suffers attenuation due to scattering and absorption of the signal by aerosols, fog, atmospheric gases and precipitation. In the event of thick fog, the atmospheric attenuation coefficient exceeds 100 dB/km, this potentially limits the achievable FSO link length to less than 1 kilometre. But even in clear atmospheric conditions when signal absorption and scattering are less severe with a combined attenuation coefficient of less than 1 dB/km, the atmospheric turbulence significantly impairs the achievable error rate, the outage probability and the available link margin of a terrestrial FSO communication system. The effect of atmospheric turbulence on the symbol detection of an OOK based terrestrial FSO system is presented analytically and experimentally verified. It was found that atmospheric turbulence induced channel fading will require the OOK threshold detector to have the knowledge of the channel fading strength and noise levels if the detection error is to be reduced to its barest minimum.
    [Show full text]
  • Modeling, Analysis, and Design of Subcarrier
    MODELING, ANALYSIS, AND DESIGN OF SUBCARRIER MULTIPLEXING ON MULTIMODE FIBER Surachet Kanprachar Dissertation submitted to the Faculty of the Virginia Polytechnic Instituted and State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Electrical Engineering Ira Jacobs, Chairman Timothy T. Pratt John K. Shaw Rogers H. Stolen Anbo Wang March, 2003 Blacksburg, Virginia Keywords: Subcarrier Multiplexing (SCM), Diversity coding, Training process, Multimode fibers, Optical fiber transmission Copyright 2003, Surachet Kanprachar MODELING, ANALYSIS, AND DESIGN OF SUBCARRIER MULTIPLEXING ON MULTIMODE FIBER by Surachet Kanprachar Ira Jacobs, Chairman Electrical Engineering (ABSTRACT) This dissertation focuses on the use of subcarrier multiplexing (SCM) in multimode fibers, utilizing carrier frequencies above what is generally utilized for multimode fiber transmission, to achieve high bit rates. In the high frequency region (i.e., frequencies larger than the intermodal bandwidth), the magnitude response of multimode fiber does not decrease monotonically as a function of the frequency but is shown to become relatively flat (but with several deep nulls) with an amplitude below that at DC. The statistical properties of this frequency response at high frequencies are analyzed. The probability density function of the magnitude response at high frequencies is found to be a Rayleigh density function. The average amplitude in this high frequency region does not depend on the frequency but depends on the number of modes supported by the fiber. To transmit a high bit rate signal over the multimode fiber, subcarrier multiplexing is adopted. The performance of the SCM multimode fiber system is presented. The performance of the SCM system is significantly degraded if there are some subcarriers located at the deep nulls of the fiber.
    [Show full text]
  • The Automatic Picture Transmission (Apt)
    https://ntrs.nasa.gov/search.jsp?R=19630013799 2020-03-24T05:25:50+00:00Z \ \ I NASA TECHNICAL NOTE NASA TN D- 1915 I o .....-::z: THE AUTOMATIC PICTURE TRANSMISSION (APT) TV CAMERA SYSTEM FOR METEOROLOGICAL SATELLITES by Rudolf A. Stampfl and William G. Stroud Goddard Space Flight Center Greenbelt, Maryland NATIONAL AERONAUTICS AND SPACE ADMINISTRATION • WASHINGTON, D. C. • NOVEMBER 1963 THE AUTOMATIC PICTURE TRANSMISSION [APT) TV CAMERA SYSTEM FOR METEOROLOGICAL SATELLITES by Rudolf A. Stampfl and William G. Stroud Goddard SPac e Flight Center SUMMARY Nimbus, the second generation meteorological satellite which is the successor to TIROS, is a stabilized platform designed for global coverage of the earth's cloud cover and for future atmospheric research. A three camera TV system operating during daylight and an infrared scanner operating during the night store the cloud data on magnetic tape for later command readout. This paper describes an additional camera system, designed for automatic and continuous real-time picture transmission during daylight. Although it is planned for trial on a TIROS satellite in a time- restricted mode, its operation on Nimbus will be continuous during daylight. The camera uses an electrostatic storage vidicon which is exposed for 40 mil­ liseconds, and read-out during the succeeding 200 seconds. The 800 line resolu­ tion and the 0.25 second scanning time per line are compatible with standard 240 rpm facsimile equipment which can be used for ground display. Full compatibility is achieved by amplitude modulation of a 2400 cps subcarrier and by transmission of a turn-on and phasing signal during the 8 seconds preceding actual picture transmission.
    [Show full text]
  • Time and Frequency Users' Manual
    ,>'.)*• r>rJfl HKra mitt* >\ « i If I * I IT I . Ip I * .aference nbs Publi- cations / % ^m \ NBS TECHNICAL NOTE 695 U.S. DEPARTMENT OF COMMERCE/National Bureau of Standards Time and Frequency Users' Manual 100 .U5753 No. 695 1977 NATIONAL BUREAU OF STANDARDS 1 The National Bureau of Standards was established by an act of Congress March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology and facilitate their effective application for public benefit To this end, the Bureau conducts research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, a technical (3) basis for equity in trade, and (4) technical services to pro- mote public safety. The Bureau consists of the Institute for Basic Standards, the Institute for Materials Research the Institute for Applied Technology, the Institute for Computer Sciences and Technology, the Office for Information Programs, and the Office of Experimental Technology Incentives Program. THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United States of a complete and consist- ent system of physical measurement; coordinates that system with measurement systems of other nations; and furnishes essen- tial services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of the Office of Measurement Services, and the following center and divisions: Applied Mathematics
    [Show full text]
  • Recommendation Itu-R Bt.1833-2*, **
    Recommendation ITU-R BT.1833-2 (08/2012) Broadcasting of multimedia and data applications for mobile reception by handheld receivers BT Series Broadcasting service (television) ii Rec. ITU-R BT.1833-2 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http://www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found. Series of ITU-R Recommendations (Also available online at http://www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management SNG Satellite news gathering TF Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1.
    [Show full text]