1、 Rec. ITU-R M.1545 1 RECOMMENDATION ITU-R M.1545*Measurement uncertainty as it applies to test limits for the terrestrial component of International Mobile Telecommunications-2000 (Question ITU-R 229/8) (2001) The ITU Radiocommunication Assembly, considering a) that Recommendation ITU-R M.1457 addre
2、sses the detailed specifications of the radio interface of International Mobile Telecommunications-2000 (IMT-2000); b) that it is reasonable to allow in practice some measurement uncertainty in the measurement method, measurement equipment and measurement test bench when the device is to be tested f
3、rom a regulatory viewpoint; c) that a device that is manufactured in one country and passes a conformance test based on regulation of that country may not be well accepted by the regulator of another country, not due to actual inadequacy of the equipment but because of difference in the concepts emp
4、loyed for handling measurement uncertainty; d) that it is essentially important to achieve a common global understanding of how measurement uncertainty is applied when test limits are defined, in conjunction with how that is incorporated into pertinent specifications; e) that from a technical perspe
5、ctive, in a case that the measurement uncertainty can be reasonably defined, the following three methods lead to the same result: “Never fail a good device under test (DUT)” principle applied to a test limit equals to the core specification value, where core specification value and measurement uncer
6、tainty are separately defined (see Annex 1, Fig. 1); “Shared risk” principle applied to a test limit calculated by relaxing the core specification value by measurement uncertainty, where core specification value and measurement uncertainty are separately defined (see Annex 1, Fig. 2); “Shared risk”
7、principle applied to a test limit which equals the core specification value that includes measurement uncertainty (see Annex 1, Fig. 3), recommends 1 that maximum allowable measurement uncertainty as it applies to test limits should be defined as a unique and consistent value associated with one or
8、a combination of measurement methods and measurement equipment to be used, when the device for terrestrial component of IMT-2000 is to be tested for conformance; 2 that in order to be consistent with industry practice, the shared risk principle should be used for all tests and that it may be decided
9、 to relax the core specification value by a certain relaxation _ *This Recommendation should be brought to the attention of Radiocommunication Study Group 1. 2 Rec. ITU-R M.1545 value that should be evaluated on a case-per-case basis taking into account different factors such as test system measurem
10、ent uncertainty (test equipment uncertainty, mismatch, and so on), and criticality for system performance; 3 that it should be clearly indicated where the relaxation value is specified; 4 that in case the measurement uncertainty cannot be reasonably and clearly defined, the “shared risk” principle s
11、hould be applied to core specification value without any relaxation. NOTE 1 Definitions applicable to this Recommendation: Measurement uncertainty: error in measurement associated with one or a combination of measurement methods and measurement equipment to be used when the device is to be tested fo
12、r conformance. Core specification value: value defined in the core specification. Test limit: threshold considered in a test to assess compliance of the device; it might be equal, relaxed or tightened compared to the corresponding core specification value. “Never fail a good DUT” principle: measurem
13、ent results are compared with test limits tolerating failures up to the measurement uncertainty (i.e. the DUT is considered to pass if the measurement result is within the test limits + tolerance up to measurement uncertainties). “Shared risk” principle: measurement results are compared with test li
14、mits (i.e. the DUT is considered to pass if the measurement result is within the test limits). ANNEX 11Examples of two criteria using “never fail a good DUT” and “shared risk” principles 1545-01+2 dB2 dB39 dBm41 dBmTest limitArea where DUT failsconformance testArea where DUTpasses conformancetestFIG
15、URE 1“Never fail a good DUT” principle where core specification valueand measurement uncertainty are separately definedExample: Core specification: no greater than 41 dBm Measurement uncertainty: 2 dB_ 1The confidence level is not considered in this Recommendation. Rec. ITU-R M.1545 3 1545-02+2 dB2
16、dB39 dBm41 dBmTest limitArea where DUT failsconformance testArea where DUTpasses conformancetestFIGURE 2Application of “shared risk” principle where test limit is calculated by relaxing the corespecification value by measurement uncertainty (when core specification value andmeasurement uncertainty a
17、re separately defined)Example: Core specification: no greater than 41 dBm Measurement uncertainty: 2 dB1545-0339 dBmTest limitArea where DUT failsconformance testArea where DUTpasses conformancetestFIGURE 3Application of “shared risk” principle where the test limit is thecore specification value that includes measurement uncertaintyExample: Core specification: (including measurement uncertainty of 2 dB): no greater than 39 dBm
