1、Union internationale des tlcommunications Place des Nations 1211 GENEVE 20 Suisse Switzerland Suiza COVERING NOTE GENERAL SECRETARIAT OF THE INTERNATIONAL TELECOMMUNICATION UNION Geneva, 3 October 2005 ITU TELECOMMUNICATION STANDARDIZATION SECTOR Subject: Erratum 1 (10/2005) to ITU-T Recommendation
2、O.172 (04/2005), Jitter and wander measuring equipment for digital systems which are based on the synchronous digital hierarchy (SDH) 1) At the end of “Introduction“, add the following paragraph: “While functional and characteristic requirements are given for the measuring equipment, the realization
3、 of the equipment configuration is not covered and should be given careful consideration by the designer and user. In particular, it is not required that all features described in this Recommendation shall be provided in one piece of equipment. Users may select those functions which correspond best
4、to their applications.“ 2) In Clause 8.6.1 “Phase amplitude error“, correct the formula as follows: Q% of setting 0.02 UIpp 3) In Clause 8.6.2, Table 4a/O.172 “Variable error (Q) of SDH tributary jitter/wander generation“, modify column header: “Signal“ with “Bit rate kbit/s“ 4) In Clause 10.6.2 “Ca
5、lculation algorithm accuracy“, modify the last sentence as follows: “ . where Z5() is specified in Table 17 and T is the measurement period.“ 5) In Clause 10.6.3 “Measurement result accuracy“, modify the last sentence as follows: “ . where Z6() is specified in Table 18 and T is the measurement perio
6、d.“ 2 6) In Clause 10.7.2 “Calculation algorithm accuracy“, modify the last sentence as follows: “ . where Z7() is specified in Table 19 and T is the measurement period.“ 7) In Clause 10.7.3 “Measurement result accuracy“, modify the last sentence as follows: “ . where Z8() is specified in Table 20 and T is the measurement period.“ and, in Table 20/O.172 “Fixed error (Z8) of frequency drift rate measurement result“, modify column header as follows: Z78(T) (ns/s2)
