DOCSLIB.ORG

Questions of the CCIR (Düsseldorf, 1990)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Questions of the CCIR (Düsseldorf, 1990) This electronic version (PDF) was scanned by the International Telecommunication Union (ITU) Library & Archives Service from an original paper document in the ITU Library & Archives collections. La présente version électronique (PDF) a été numérisée par le Service de la bibliothèque et des archives de l'Union internationale des télécommunications (UIT) à partir d'un document papier original des collections de ce service. Esta versión electrónica (PDF) ha sido escaneada por el Servicio de Biblioteca y Archivos de la Unión Internacional de Telecomunicaciones (UIT) a partir de un documento impreso original de las colecciones del Servicio de Biblioteca y Archivos de la UIT. (ITU) ﻟﻼﺗﺼﺎﻻﺕ ﺍﻟﺪﻭﻟﻲ ﺍﻻﺗﺤﺎﺩ ﻓﻲ ﻭﺍﻟﻤﺤﻔﻮﻇﺎﺕ ﺍﻟﻤﻜﺘﺒﺔ ﻗﺴﻢ ﺃﺟﺮﺍﻩ ﺍﻟﻀﻮﺋﻲ ﺑﺎﻟﻤﺴﺢ ﺗﺼﻮﻳﺮ ﻧﺘﺎﺝ (PDF) ﺍﻹﻟﻜﺘﺮﻭﻧﻴﺔ ﺍﻟﻨﺴﺨﺔ ﻫﺬﻩ .ﻭﺍﻟﻤﺤﻔﻮﻇﺎﺕ ﺍﻟﻤﻜﺘﺒﺔ ﻗﺴﻢ ﻓﻲ ﺍﻟﻤﺘﻮﻓﺮﺓ ﺍﻟﻮﺛﺎﺋﻖ ﺿﻤﻦ ﺃﺻﻠﻴﺔ ﻭﺭﻗﻴﺔ ﻭﺛﻴﻘﺔ ﻣﻦ ﻧﻘﻼ ً◌ 此电子版（PDF版本）由国际电信联盟（ITU）图书馆和档案室利用存于该处的纸质文件扫描提供。 Настоящий электронный вариант (PDF) был подготовлен в библиотечно-архивной службе Международного союза электросвязи путем сканирования исходного документа в бумажной форме из библиотечно-архивной службы МСЭ. © International Telecommunication Union XVII A.R DUSSGLDORF 21.5 - 1.6 1990 CCIR XVIIth PLENARY ASSEMBLY DUSSELDORF, 1990 INTERNATIONAL TELECOMMUNICATION UNION QUESTIONS OF THE CCIR, 1990 VOLUME XV SG 1 SPECTRUM MANAGEMENT TECHNIQUES SG 12 INTER-SERVICE SHARING AND COMPATIBILITY SG 5 RADIO WAVE PROPAGATION IN NON-IONIZED MEDIA SG 6 RADIO WAVE PROPAGATION IN IONIZED MEDIA SG 7 SCIENCE SERVICES INTERNATIONAL RADIO CONSULTATIVE COMMITTEE Geneva, 1990 CCIR 1. The International Radio Consultative Committee (CCIR) is the permanent organ of the International Telecommunication Union responsible under the International Telecommunication Convention "... to study technical and operating questions relating specifically to radiocommunications without limit of frequency range, and to issue recommendations on them../7 (Inter­ national Telecommunication Convention, Nairobi 1982, First Part, Chapter I, Art. 11, No. 83)? 2. The objectives of the CCIR are in particular: a) to provide the technical bases for use by administrative radio conferences and radiocommunication services for efficient utilization of the radio-frequency spectrum and the geostationary-satellite orbit, bearing in mind the needs of the various radio services; b) to recommend performance standards for radio systems and technical arrangements which assure their effective and compatible interworking in inter­ national telecommunications; c) to collect, exchange, analyze and disseminate technical information resulting from studies by the CCIR, and other information available, for the development, planning and operation of radio systems, including any necessary special measures required to facilitate the use of such information in developing countries. * See also the Constitution of the ITU, Nice, 1989, Chapter 1, Art. 11, No. 84. COVERING NOTE GENERAL SECRETARIAT INTERNATIONAL TELECOMMUNICATION UNION Subject: ADDENDUM No. 2 Geneva, 6 September 1993 VOLUME XV-1 CCIR XVIIth PLENARY ASSEMBLY DUSSELDORF, 1990 Study Group 7 Add the following new Questions*: - Question ITU-R 201/7, page 151 - Question ITU-R 202/7, page 152 - Question ITU-R 203/7, page 153 - Question ITU-R 204/7, page 154 * These Questions were adopted between March and M y 1993. Union internationale des telecommunications Place des Nations 1211 GENEVE 20 Suisse-Switzerland-Suiza Q. ITU-R 201/7 151 QUESTION ITU-R 201/7 TWO-WAY TIME TRANSFER THROUGH COMMUNICATION SATELLITES (1993) The ITU Radiocommunication Asembly, considering a) that the theoretical accuracy and stability of the two-way exchange of timing signals through communication satellites has great promise; b) that the experimental results on the short-term time stability are consistent with theory; c) that sufficient experience for long-term time stability studies has not yet been obtained; d) that systematic variations in the delays of the transmitting and receiving elements for this technique need to be better understood and documented; e) that there is not an agreed-upon method for quantifying the time accuracy, the time stability and the frequency comparison capability of this technique; f) that many of the world timing centres are implementing this technique because of its apparent potential, decides that the following Question should be studied 1. What are the performance levels that can be achieved in practice when using the two-way satellite time transfer technique with respect to the following: the long-term time stability of this technique; the time accuracy of this technique; the frequency comparison capability of this technique; and comparisons of the performance of the two-way technique with similar results from alternative methods, such as use of GPS satellites? 2. What are the causes and cures for systematic delay variations that may be perturbing this technique? 3. What standard data format, if any, can be agreed upon and implemented for comparison between the different timing centres? 152 Q. ITU-R 202/7 QUESTION ITU-R 202/7 FREQUENCY SHARING AND PROTECTION BETWEEN SPACE VLBI AND OTHER SPACE RESEARCH SYSTEMS (1993) The ITU Radiocommunication Assembly, considering a) that there are requirements to use spacecraft for conducting very long baseline interferometry (VLBI); b) that space VLBI observations usually require wideband data transmission in the space-to-Earth direction; c) that space VLBI systems require precision up-link and corresponding down-link phase reference signals which need to be protected from interference; d) that there may be a potential for mutual interference when space VLBI systems are operated in die same frequency bands used by other space research systems, decides that the following Question should be studied 1. How do the technical and operating characteristics of space VLBI systems affect the feasibility of sharing with other space research systems? 2. Under what conditions and to what extent is it possible for space VLBI systems to share frequency bands with other space research systems? 3. What frequency bands are suitable for sharing between space VLBI systems and other space research systems? Q. ITU-R 203/7 153 QUESTION ITU-R 203/7 CHARACTERISTICS AND TELECOMMUNICATIONS REQUIREMENTS FOR SPACE VLBI (1993) The ITU Radiocommunication Assembly, considering a) that the angular resolution of measurements made by very long baseline interferometry (VLBI) techniques is limited by the distance between two observing stations; b) that, compared to the largest possible distance between two observing stations on Earth, this baseline distance may be substantially increased by locating one or more of the observing stations in space; c) that by conducting VLBI measurements which utilize spacecraft, it is possible to eliminate the limitations of ground-based observations caused by the absorption, path length fluctuations and noise contributions by the atmosphere; d) that space VLBI will eventually provide invaluable knowledge of physical parameters leading to highly accurate determination of: radiosources structure; deep-space navigation; geodynamics; astrometry; satellite's orbit parameters; e) that the transmission of wideband space VLBI data from space-to-Earth is required; f) that space VLBI systems require the transmission of highly accurate time/phase reference signals from Earth-to-space and space-to-Earth, decides that the following Question should be studied 1. What are the technical characteristics of space VLBI systems with regard to their requirements for telecommunication links? 2. What are the orbital characteristics of spacecraft engaged in space VLBI, as they may affect the utilization of radio-frequency bands and the feasibility of sharing (see Question ITU-R 202/7)? 3. Considering the effects of radio-wave propagation, and available techniques; what are the frequency bands most suitable for the precise time/phase transmission; what are the frequency bands and bandwidths most suitable for the wideband data transmission space-to-Earth? 154 Q. ITU-R 204/7 QUESTION ITU-R 204/7* SHARING OF THE BAND 1 675-1 710 MHz BETWEEN THE MOBILE-SATELLITE SERVICE AND THE METEOROLOGICAL-SATELLITE AND METEOROLOGICAL AIDS SERVICES (1993) The ITU Radiocommunication Assembly, recognizing a) that the World Administrative Radio Conference (Malaga-Torremolinos, 1992) (WARC-92) decided that, in the band 1 675-1 710 MHz, stations in the mobile-satellite service shall not cause harmful interference to, nor constraint the development of, the meteorological-satellite and meteorological aids services and the use of this band shall be subject to the provisions of Resolution No. 46 (WARC-92) (Footnote 735A (WARC-92) to the Radio Regulations); b) that Resolution No. 213 of WARC-92 "Sharing studies concerning the use of the bands 1 492-1 525 MHz and 1 675-1 710 MHz in Region 2 by the mobile-satellite service" resolves that studies be undertaken by the ex-CCIR to examine the operational and technical measures that would facilitate sharing; c) that this Resolution invites the ex-CCIR also to study as a matter of urgency the technical and operational issues relating to the sharing of these bands, noting a) that, as for the band 1 675-1 710 MHz, Recommendation ITU-R SA.514** and Reports ITU-R SA.395**, ITU-R SA.541**, ITU-R SA.851** and ITU-R SA.1121** contain some information on this matter, decides that the following Question should be studied 1. What are the operational and technical measures appropriate for preventing harmful interference to
Load more

Recommended publications
  • AM Loop Antennas AM LOOP ANTENNAS Introduction
    AM Loop Antennas AM LOOP ANTENNAS Introduction An AM loop antenna is one of the true marvels of electronics. Requiring no power, it takes advantage of the resonant properties of an inductor and a capacitor connected in parallel to receive weak AM stations. The "loop" part of the antenna is the inductor, and the tuning capacitor makes it resonate at a desired frequency. As a boy in Abilene in 1967, I discovered the basic principle of the loop antenna. By removing a relatively small spiral loop in my five tube table radio, and substituting a much larger loop salvaged from an older radio, I could receive my favorite station - KLIF from Dallas better. I hid the loop in a cardboard holder featuring the logo of a favorite rock band, and enjoyed many hours of good listening. Lacking the mathematical background to understand antenna theory - I could not take the concept to the next phase: designing my own loop. Nevertheless, the spiral loop - combined with the antenna section of the radio's tuning capacitor - formed a very good loop antenna. I understood quite well that the bigger the loop, the more stations I could receive. The schematic diagram of an AM loop antenna is shown below. It consists of an inductive winding, which is supported on a frame, and a variable tuning capacitor that can be salvaged from a junk radio. The inductive winding consists of a primary, which forms a resonant network with the tuning capacitor, and a secondary "sense" winding that can be connected to a radio. In practice, however, the sense winding is not needed if the loop antenna can be placed near the radio - mutual coupling will take place with the antenna in the radio.
    [Show full text]
  • Crystal Radio Projects Listening to Longwave ARRL RFI Book
    review a new edition. Such is the Crystal Radio ARRL RFI Book 36th edition of the ARRL Repeater Our high-tech era brings Directory for 2007-2008. No, don’t Projects convenience at the expense of yawn! What’s ho-hum about the As technology speeds ahead at radio interference. Power lines, book with the greatest potential of a head-spinning pace, many radio telephones, computers, lighting actually getting new hams on the experimenters delight in returning fixtures, electronic accessories, air? to the days of old, marveling once home appliances, TV sets, radio again at the reception of signals equipment and other electrically- during a simpler time. operated devices are a limitless Crystal radio sets require no source of unwanted signals. external source of power; they de- The most comprehensive rive their earphone volume purely volume devoted to curing radio from the signal voltage itself. Me- frequency interference (RFI) prob- dium wave AM broadcasters are the lems is unquestionably this second most common targets for reception, edition of the formidable RFI Book but shortwave broadcasters, CB from the American Radio Relay stations and even aircraft commu- League (ARRL). nications can be heard as well. Publishers of the Xtal Set Society Newsletter periodically assemble articles and projects into Key chapters include: · Who is on the air, and when book form; their latest assemblage and where to listen to longwave of volumes 12 and 13 is such a communications. publication. · Transmitters (lowfer), receivers, 135 well-illustrated pages converters and antennas for contain instructional details on longwave. The bulk of the Repeater · Longwave listening tips for Directory – which comes in a building your own headset and cat’s beacon hunters, logging your whisker crystal, simple one-tube catches, and equipment.
    [Show full text]
  • Sue: Hear Hidden Satell Rals Litow Filters Im Pro Reception Shor Ave Listeni Ij)Ginia to Zambia World Band Cente °Fl1uo O Iü S
    o t is-sue: Hear Hidden Satell Rals litow Filters Im pro Reception Shor ave Listeni ij)ginia to Zambia World Band Cente °fl1Uo O iü s Plus: CB, S. EJT Pg:DOUDC43'- Ham Radio; 0C2',.FC9g I . lit LAST WORD ERFORLNCE THE ICOM IC -781 HF TRANSCEIVER TRANSMIT 14.195.134 .. r.. = PHONES t; R IC -781 14.205.00 DELAY DRIVE NB LEVEL BIK.WIDiH GC .-_ A , : '.DMP .IB R, GAIN MCROPHONE- 1[01-O45 AMU St7h Sv( Nothing compares to the captivating Whether you aspire to DX, contest or experience of operating the finest transceiver enjoy legendary performance, the IC -781 on the market, the IC -781. The exhilaration inspires countless hours of devoted of operating the IC-781 is matched only by attention. Backed by a service commitment the luxury of its crystal clear communications. second to none, four factory service centers Designed for rigorous operation, the and a one-year factory warranty, the IC -781 IC-781 is the result of extreme dedication, characterizes Icom's dedication to excellence. exceptional craftmanship precision and V I, Miki L: m ui: lti: :iÌ- 1. till, .,,,!t 1li.,1+. engineering. The IC -781 fuses tre perfect Hotline at 1-800-999-9877. blend of features such as driving power, CORPORATE HEADQUARTERS: ICOM America, Inc.. 2380 -116th .Ave. N.E.. Bellevue, WA 98004 incredible clarity, a Multi -Function CRT CUSTOMER SERVICE HOTLINE (206) 454.7619 CUSTOMER SERVICE CENTERS: 3150 Premier Drive, Suite 126. Irving. TX 75063 Display, Spectrum Scope and Icclm's 1777 Phoenix Parkway. Suite 201. Atlanta.
    [Show full text]
  • Tektronix: Glossary Video Terms and Acronyms
    Glossaryvideo terms and acronyms This Glossary of Video Terms and Acronyms is a compilation of material gathered over time from numer- ous sources. It is provided "as-is" and in good faith, without any warranty as to the accuracy or currency of any definition or other information contained herein. Please contact Tektronix if you believe that any of the included material violates any proprietary rights of other parties. Video Terms and Acronyms Glossary 1-9 0H – The reference point of horizontal sync. Synchronization at a video 0.5 interface is achieved by associating a line sync datum, 0H, with every 1 scan line. In analog video, sync is conveyed by voltage levels “blacker- LUMINANCE D COMPONENT E A than-black”. 0H is defined by the 50% point of the leading (or falling) D HAD D A 1.56 µs edge of sync. In component digital video, sync is conveyed using digital 0 S codes 0 and 255 outside the range of the picture information. 0.5 T N E 0V – The reference point of vertical (field) sync. In both NTSC and PAL CHROMINANCE N COMPONENT O systems the normal sync pulse for a horizontal line is 4.7 µs. Vertical sync P M is identified by broad pulses, which are serrated in order for a receiver to O 0 0 C maintain horizontal sync even during the vertical sync interval. The start H T 3.12 µs of the first broad pulse identifies the field sync datum, 0 . O V B MOD 12.5T PULSE 1/4” Phone – A connector used in audio production that is characterized -0.5 by its single shaft with locking tip.
    [Show full text]
  • Build Your Own Low-Power Transmitters: Projects for the Electronics Experimenter
    Build Your Own Low-Power Transmitters Projects for the Electronics Experimenter This Page Intentionally Left Blank Build Your Own Low-Power Transmitters Projects for the Electronics Experimenter Rudolf F. Graf William Sheets Boston Oxford Auckland Johannesburg Melbourne New Delhi Newnes is an imprint of Butterworth–Heinemann. Copyright © 2001 Rudolf F. Graf and William Sheets A member of the Reed Elsevier group All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or trans- mitted in any form or by any means, electronic, mechanical, photocopying, record- ing, or otherwise, without the prior written permission of the publisher. Recognizing the importance of preserving what has been written, Butterworth– Heinemann prints its books on acid-free paper whenever possible. Butterworth–Heinemann supports the efforts of American Forests and the Global ReLeaf program in its campaign for the betterment of trees, forests, and our environment. Library of Congress Cataloging-in-Publication Data Graf, Rudolf F. Build your own low-power transmitters : projects for the electronics experimenter / Rudolf F. Graf, William Sheets. p. cm. ISBN 0-7506-7244-7 (alk. Paper) 1. Radio—Transmitters and transmission—Design and construction— Amateurs’ manuals. 2. Low voltage systems—Designs and construction— Amateurs’ manuals. I. Sheets, William. II. Title. TK6561 .G67 2001 621 .384’131—dc21 2001030550 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. The publisher offers special discounts on bulk orders of this book. For information, please contact: Manager of Special Sales Butterworth–Heinemann 225 Wildwood Avenue Woburn, MA 01801-2041 Tel: 781-904-2500 Fax: 781-904-2620 For information on all Newnes publications available, contact our World Wide Web home page at: http://www.newnespress.com.
    [Show full text]