1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU SERIES O: SPECIF EQUIPMENT General CAT ONS OF MEASUR 0.9 (03/99) NG Measuring arrangements to assess the degree of unbalance about earth ITU-T Recommendation 0.9 (Previously CCIlT Recommendation) ITU-T O-SERI
2、ES RECOMMENDATIONS SPECIFICATIONS OF MEASURING EQUIPMENT General .9 Maintenance access Automatic and semi-automatic measuring systems Equipment for the measurement of analogue parameters Equipment for the measurement of digital and analogueidigital parameters o. 1 0-0.1 9 O. 20-0.39 0.40-0.129 O. 13
3、0-0.199 For further details, please refer to ITU-T List of Recommendations. MEASURING ARRANGEMENTS TO ASSESS THE DEGREE OF UNBALANCE ABOUT EARTH Summary This Recommendation provides procedures to assess the degree of unbalance about earth and defines the applicable measuring arrangements. Seven para
4、meters, which are most relevant in practice, are covered. In addition, some basic requirements concerning the measurement of unbalance are given. Source ITU-T Recommendation 0.9 was revised by ITU-T Study Group 4 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 26th of M
5、arch 1999. Keywords Common-mode rejection, input longitudinal interference loss, longitudinal conversion loss, longitudinal conversion transfer loss, output signal balance, test bridges, transverse conversion loss, transverse conversion transfer loss, unbalance measuring arrangements Recommendation
6、0.9 (03/99) I STDeITU-T RECMN 0.9-ENGL 1999 UBb2591 ObbD891 141 FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The IT Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is resp
7、onsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by th
8、e ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within ITU-Ts purview, the necessary stan
9、dards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation the term recognized operating agency (ROA) includes any individual, company, corporation or governmental organization that operates a public correspondence service. The terms Administration, ROA and public corr
10、espondence are defined in the Constitution of the ITU (Geneva, 1992). INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning
11、the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by pate
12、nts, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 1999 All rights reserved. No part of this publication may be reproduced or ut
13、ilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the IT. 11 Recommendation 0.9 (03/99) - - 1 2 3 4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 5 5.1 5.2 5.3 5.4 STD-ITU-T RECMN 0.9-ENGL 1999 9 4662591 0660632 OB8 ia CONTENTS Scope
14、 References Abbreviations . Measuring arrangements . longitudinal conversion loss (LCL) transverse conversion loss (TCL) . longitudinal conversion transfer loss (LCTL) transverse conversion transfer loss (TCTL) . input longitudinal interference loss (ILIL) . common-mode rejection (CMR) output signal
15、 balance (OSB) . Requirements for the measuring arrangements Inherent balance Impedances Z,. Z 2,. and ZL Measuring and generating the test signais Other considerations . Appendix I . Aspects of conversion from longitudinal to transversal signals at analogue I . 1 Introduction 1.2 1.3 1.4 ports in s
16、ome practical cases Calculation of the longitudinal conversion loss . The difference between LCL, and LCL, in a practical case: two examples Additional insight into Longitudinal Conversion Loss Recommendation 0.9 (03/99) _ Page 1 1 2 2 2 3 3 4 5 6 7 8 8 8 8 9 9 9 10 11 13 . 111 Recommendation 0.9 ME
17、ASURING ARRANGEMENTS TO ASSESS THE DEGREE OF UNBALANCE ABOUT EARTH (Geneva, 1972; amended at Malaga-Torremolinos, 1984; Melbourne, 1988; revised in 1999) 1 Scope This Recommendation describes arrangements for measuring the following parameters: - longitudinal conversion loss; - transverse conversion
18、 loss; - longitudinal conversion transfer loss; - transverse conversion transfer loss; - input longitudinal interference loss; - common-mode rejection; - output signal balance. In practice, the above parameters are the seven most significant unbalance parameters. Limits for these parameters, special
19、 considerations for terminating impedances and the measurement frequencies to be used are given in the relevant Recommendation for the item under test. This Recommendation is in agreement with the principles, the nomenclature and the definitions, addressed in Recommendation G. 1 17 11, which conside
20、rs the transmission aspects of unbalance about earth. References are made in the following clauses to the appropriate parts of Recommendation G. 1 17 i. In clause 5, guidance is given regarding the construction of a test bridge along with values of the required components. 2 References The following
21、 ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recom
22、mendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. i ITU-T Recommendation G. 1 17 (1 996), Transmission aspects of
23、unbalance about earth. 2 CCITT Recommendation 4.45 (1 984), Transmission characteristics of an analogue international exchange. 3 ITU-T Recommendation O. 133 (1 993), Equipment for measuring the performance of PCM encoders and decoders. Recommendation 0.9 (03/99) - 1 STDmITU-T RECMN O-9-ENGL 1997 H
24、LiBb2591i ObbO:l dB and measured as shown in Figure 1. This technique is applicable to either the input or output terminals, e.g. transpose terminals a and b with d and e respectively. (See 4.1.3/G. 1 17 i.) + - G NOTE -This test bridge configuration, with transversal impedance Z, and longitudinal i
25、mpedance Z, does not in all cases represent conditions found in practice. Thus, some care is needed when translating measured unbalance parameters into unbalance information applicable to practical cases. This is discussed in more detail in Appendix I. Signal generator. For details about Z, cries J
26、ieries K ieries L Series M Series N Series O Series P Series Q Series R Series S Series T Series U Series V Series X Series Y Series Z ITU-T RECOMMENDATIONS SERIES Organization of the work of the ITU-T Means of expression: definitions, symbols, classification General telecommunication statistics Gen
27、eral tariff principles Overall network operation, telephone service, service operation and human factors Non-telephone telecommunication services Transmission systems and media, digital systems and networks Audiovisual and multimedia systems Integrated services digital network Transmission of televi
28、sion, sound programme and other multimedia signals Protection against interference Construction, installation and protection of cables and other elements of outside plant TMN and network maintenance: international transmission systems, telephone circuits telegraphy, facsimile and leased circuits Mai
29、ntenance: international sound programme and television transmission circuits Specifications of measuring equipment Telephone transmission quality, telephone installations, local line networks Switching and signalling Telegraph transmission Telegraph services terminal equipment Terminals for telematic services Telegraph switching Data communication over the telephone network Data networks and open system communications Global information infrastructure and Internet protocol aspects Languages and general sohare aspects for telecommunication systems Printed in Switzerland Geneva. 1999
