1、 Recommendation ITU-R TF.768-7(04/2011)Standard frequencies and time signalsTF SeriesTime signals and frequency standards emissionsii Rec. ITU-R TF.768-7 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spect
2、rum 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
3、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 stateme
4、nts 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 ava
5、ilable 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 satellit
6、e 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
7、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. Electronic Publication Geneva, 2011 ITU 2011 All rights reserved. No part of this publication may be reproduced, by any mean
8、s whatsoever, without written permission of ITU. Rec. ITU-R TF.768-7 1 RECOMMENDATION ITU-R TF.768-7 Standard frequencies and time signals (1992-1994-1995-1997-2001-2002-2003-2011) Scope This Recommendation provides the rationale and procedures for providing stable and accurate time and frequency re
9、ference signals by broadcast services. The ITU Radiocommunication Assembly, considering a) the continuing need in all parts of the world for readily available standard frequency and time reference signals that are internationally coordinated; b) the advantages offered by radio broadcasts of standard
10、 time and frequency signals in terms of wide coverage, ease and reliability of reception, achievable level of accuracy as received, and the wide availability of relatively inexpensive receiving equipment; c) that Article 26 of the Radio Regulations is considering the coordination of the establishmen
11、t and operation of services of standard-frequency and time-signal dissemination on a worldwide basis; d) that a number of stations are now regularly emitting standard frequencies and time signals in the bands allocated by WARC-79 and that additional stations provide similar services using other freq
12、uency bands; e) that these services operate in accordance with Recommendation ITU-R TF.460 which establishes the internationally coordinated time (UTC) system; f) that other broadcasts exist which, although designed primarily for other functions such as navigation or communications, emit highly stab
13、ilized carrier frequencies and/or precise time signals that can be very useful in time and frequency applications, recommends 1 that, for applications requiring stable and accurate time and frequency reference signals that are traceable to the internationally coordinated UTC system, serious consider
14、ation should be given to the use of one or more of the broadcast services listed and described in that part of the ITU-R website concerning Radiocommunication Study Group 7, select: standard-frequency and time signals; 2 that in the case of a radio time signal generated directly by a laboratory desi
15、gnated “k”, the measured delay between the time of emission of the signal and UTC(k) should be published; 3 that in the case of a radio time signal controlled by a clock at the transmitting station and measured at the laboratory “k”, it should be stated explicitly whether the published times in rela
16、tion to UTC(k) refer to reception or emission and what corrections for propagation and receiver delays should be or have been applied; 2 Rec. ITU-R TF.768-7 4 that administrations responsible for the various broadcast services disseminating standard-frequency and time should make every effort to provide Radiocommunication Study Group 7 with accurate and up-to-date information, particularly when changes to those broadcast services occur. (Administrations are also requested to send such information to the Bureau International des Poids et Mesures (BIPM).)
