1、INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU K.38 (I 0/96) SERIES K: PROTECTION AGAINST INTERFERENCE Radiated emission test procedure for physically large systems ITU-T Recommendation K.38 (Previously CCIV Recommendation) STD-ITU-T RECMN K-gB-ENGL L77b
2、48b259L Ob3L004 b84 M ITU-T K-SERIES RECOMMENDATIONS PROTECTION AGAINST INTERFERENCE ForfUrther details, please refm to ITU-T List of Recommendations. FOREWORD The IT-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The IT-T is res
3、ponsible for studying technical, operating and tariff questions and issuing Recommen- dations 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
4、 the IT-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the IT-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). ITU-T Recommendation K.38, was prepared by IT-T Study Group 5
5、(1993-1996) and was approved by the WTSC (Geneva, October 9-18,1996). NOTES 1. telecommunication administration and a recognized operating agency. 2. follows: In this Recommendation, the expression “Administration” is used for conciseness to indicate both a The status of annexes and appendices attac
6、hed to the Series K Recommendations should be interpreted as - - an annex to a Recommendation forms an integral part of the Recommendation; an appendix to a Recommendation does not form part of the Recommendation and only provides some complementary explanation or information specific to that Recomm
7、endation. O ITU 1997 Ali rights reserved. 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 the ITU. Recommendation IC38 (10196) 1 STD-ITU-T RECMN K.38-ENGL L99b E
8、YBb259L Ob3L00b 457 E CONTENTS 1 Scope 2 Normative references . 2.1 Bibliography . 3 Definitions and abbreviations . 3.1 Definitions 3.2 Abbreviations 4 Minimurn representative system . 4.1 Determination of minimum representative system . 4.2 New functional modules . 5 Generai operational conditions
9、 . 5.1 Equipment configuration 5.2 Equipment cable layout 5.3 Exercising equipment . 5.4 Laboratory environment . 6 Measurement method . 7 Test results report . Page 1 1 1 2 7 11 Recommendation K.38 (10196) STD-ITU-T RECMN K.3A-ENGL 177b M Lf8b257L Ob31007 373 M SUMMARY This Recommendation specifies
10、 the technical requirements for the radiated emission measurement procedure for physically large systems used within the public telecommunication network. A minimum representative system is defined, which is used for compliance testing of physically large telecommunication systems. Recommendation K.
11、38 (10/96) . 111 Recommendation K.38 RADIATED EMISSION TEST PROCEDURE FOR PHYSICALLY LARGE SYSTEMS (Geneva, 1996) 1 Scope This Recommendation specifies the techical requirements for the radiated emission measurement procedure for physically large systems used within the public telecommunication netw
12、ork, with the exception of radio equipment. It applies to physically large systems which are comprised of equipments or systems requiring installation documentation specific for those sites at which they are to be installed. In order to demonstrate compliance of such systems, a minimum representativ
13、e system is defned, which is used for compliance testing. Installations built from units of the complying minimum representative system are deemed to satis the radiated emission requirements. The minimum representative system is representative of installed systems in terms of function (which include
14、s at least one of each functional unit type) and electromagnetic radiation characteristics. The minimum representative system is subsequently referred to in this Recommendation as the Equipment Under Test (EUT), to be used for compliance testing. Minimum representative systems shall be tested on an
15、Open Area Test Site (OATS) or in a suitable chamber, the limits to be used are those as specified in CISPR 22 13. 2 Normative references The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At
16、 the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references list
17、ed below. A list of the currently valid IT-T Recommendations is regulary published. i CISPR 22, Limits and methods of measurement of radio disturbance characteristics of information technology equipment. 2 CISPR Publication No. 16, CISPR specijication for radio interference measuring apparatus and m
18、easurement methods. 3 IEC 50( 16 1): 1990, International Electrotechnical Vocabulary - Chapter 161: Electromagnetic compatibility. 2.1 Bibliography - ETS 300 127, Equipment Engineering (EE) Radiated emission testing of physically large telecommunications installations. 3 Definitions and abbreviation
19、s 3.1 Definitions This Recommendation defines the following terms, together with those from IEC 50(161) 3. 3.1.1 intended to be marketed as such. system: A set of subsystems which, when connected together, produce a fully operational product and is 3.1.2 communicate with other equipments via well-de
20、fined interfaces and protocols. subsystem: A grouping of functional units which perform specific functions within the host system and which Recommendation K.38 (10196) 1 STD-ITU-T RECMN K-3A-ENGL 1776 M 48b257L Ob31007 Ibb 3.1.3 with other functional units to produce the required subsystem. function
21、al unit: A grouping of electronic hardware which performs specific functions, but may be connected 3.1.4 new functional module: A replacement and/or addition for any grouping or arrangement of electronic hardware (with its associated mechanical packaging and interconnections), which enhances or impr
22、oves the system operation. 3.1.5 plane. test site: This should be an OATS, with reflecting ground plane, or a suitable chamber with reflecting ground 3.1.6 minimum representative system: The minimum representative system is representative of installed systems in terms of function (which includes at
23、least one of each functional unit type) and electromagnetic radiation characteristics. This shall be equipped to at least the minimum configuration which could be offered for sale for use as an actual system. It excludes any operational equipment connected for the purpose of monitoring or system mea
24、surements and which are connected for a temporary period. An example of how the EUT is to be selected is given in Figure 1. 3.1.7 unit is the point at which cabling fiom the system is connected to the cabling from external units. cable distribution point: The cable distribution point is the interfac
25、e at which cabling shall be terminated; this 3.1.8 which has a total dimension exceeding that which is practical for testing on a conventional 10 m test site. physically large system: A group of racks functionally connected to form a commercially specified system, 3.2 Abbreviations This Recommendati
26、on uses the following abbreviations EUT Equipment Under Test OATS Open Area Test Site 4 Minimum representative system The recommended method for determining the minimum representative system is given here. Operators have the option to accept testing by alternative methods but these methods carry a h
27、igher risk of the telecommunications system causing interference. 4.1 Determination of minimum representative system The minimum representative system is a system which contains the minimum number of units needed to perform all functions specified for the system. 4.2 New functional modules Functiona
28、l modules used in the system tests may be individually characterized in a defined test facility (see 5.1). This characterization may then be used as a reference to determine the effect of any significant design changes. Using this technique, the performance of new functional modules may be assessed
29、and the test plan, written in such a way as to demonstrate that the representative system continues to conform when a functional module has been replaced by a new functional module. The results obtained for new functional modules shall be compared with those from the previous module. The manufacture
30、r shall clearly demonstrate and document the reasons why a new functional module does not require a complete representative system retest. If the module constitutes a major change to the system configuration, a complete representative system test shall be performed. 2 Recommendation K.38 (10196) Sub
31、system A Subsystem B Subsystem N Subsystem A Subsystem B Unit cl u o o !- 7 ! ! ! bl ! I I L _-_-_-_ -I U -! I I b, i !- i i L _ -I Subsystem N Unit CI 7 El 7 I I L -.- -I !- i “I i r- i i i n2 I L _-_-_-_ J Representative system J System This unit selected from the system for test as part of the re
32、presentative system - - -_ I This unit not selected from the system for test as I L i i part of the representative system Figure 1X.38 - Example of selection of representative system 5 General operational conditions 5.1 Equipment configuration The EUT shall conform to the manufacturers normal instal
33、lation practice. There exists for each EUT a minimum set of interface lines which is required for the operation of the system and this number shall be defned for each EUT and identified in the test report. The EUT shall be assembled in such a way that emissions are maximized within any limitations i
34、mposed by normal installation practice. 5.1.1 Equipment boundary For the purpose of determining the equipment boundary, ffom which the tests distance is taken, the equipment boundary shall be the straight line envelope around the EUT, this includes the cables specified for attachment to the EUT for
35、the purpose of test. Measurement distances are to be taken fkom this line. Recommendation IC38 (10/96) 3 5.2 Equipment cable layout 5.2.1 Intra-system cabling All cables internal to the system, and used for its operation, shall be connected and be of such a length and type required for the normal op
36、eration of the system. These shall be routed in accordance with the relevant system installation instructions, such that these are srpical of an installed system. The system shall normally be configured in accordance with CISPR 22 requirements for floor standing equipment. An alternative Set-up usin
37、g a raised floor is acceptable for systems operated in this way. If raised floor systems be characterized as the worst case and used for testing, and if the inter-unit cable routing is into the raised floor system, the effect of the raised floor system shall be examined. The raised floor shall be le
38、ft in place if it forms part of the system screen, but where the raised floor is not intended to be used as a screen, then in order to prevent incidental screening of emissions, the floor panels shall be removed for the duration of the test. 5.2.2 Interface cabling Cables between the system, the dis
39、tribution point and external units, shall be of the type as specified by the system supplier or as detailed by customer requirements, and shall follow the relevant system installation practice. Care must be taken to ensure that noise fiom the test and exercising equipment does not contribute to the
40、emissions ftom the representative system. The method of orientating and terminating the cables shall be noted in the test report. The emission contributions ftom the system, cables and distribution point (where all of these elements are involved) are difficult to separate; there are two cases to be
41、considered: 1) unscreened cable systems; 2) screened cable systems. Screening is achieved by one of two methods: a) b) by use of screened cabling; by the use of a screened floor or ducted systems in which unscreened cabling is run. Measurement of these installation practices is performed as describe
42、d in 5.2.2.1 and 5.2.2.2. 5.2.2.1 Unscreened cable systems Wherever the distribution point is located, measurement shall be made using a length of unscreened cabling configured as described in 5.2.2.1.1 and 5.2.2.1.2. Beyond this minimum length, the cabling shall be taken off the measurement site be
43、low the ground plane to the exercising equipment. Where ths is not practicable the cabling may run in screened sleeving which is bonded to the measurement site ground plane. Two types of cable installation practice shall be considered. 5.2.2.1.1 Overhead cable systems An overhead cable system is def
44、ined as one where cables are routed above the equipment. On exiting from the EUT, all cabling shall run perpendicularly fkom the EUT in the horizontal plane for 1.5 metres, before dropping to the ground plane. Support of the cabling shall be of the type specified by the system supplier, or as detail
45、ed by customer requirements, and shall follow the relevant system installation practice. Where the system supplier or customer do not specifi cable supports, then non-conducting unscreened cable supports shall be used. The height and position of the cables shall be noted in the test report (see Figu
46、re 2). The cabling shall be taken off the measurement site below the ground plane to the exercising equipment. Where this is not practicable, the cabling may run in screened sleeving which is bonded to the measurement site ground plane. 5.2.2.1.2 Raised floors Where a raised floor system is used dur
47、ing testing (but the raised floor does not form part of the screen) then all cabling will drop through the raised floor towards the ground plane and run perpendicularly from the EUT in the horizontal plane for 1.5 metres, the raised floor being removed (see 5.2.1). The cabling shall then be taken of
48、f the measurement site 4 Recommendation K.38 (10196) STD-ITU-T RECMN K-38-ENGL L77b 0 Li8b257L Db3LOL2 750 II below the ground plane to the exercising equipment. Where this is not practicable the cabling may run in screened sleeving, which is bonded to the measurement site ground plane. All exposed,
49、 unscreened cabling, shall be on a support at a height of 10 cm (see Figure 3). The support shall be of the type specified by the system supplier, or as detailed by customer requirements, and shall follow the relevant system installation practice. Where the system supplier or customer do not speciij cable supports, then non-conducting, unscreened cable supports shall be used. distribution Screening sleeve bonded to ground plane TO507040-61dO2 I NOTE 1 -The EUT is separated from the ground plane with an electrically isolating support
