1、CCITT FASCICLE IV.3 * 4862593 0505389 7 W i The three ranges are shown in Figure 1/M.530 in relation to a typical distribution of level values. A suitable value for y in Figure 1/M.530 is considered to be 2 S, where S is the observed standard deviation. This concept is the basis of Table 1/M.530. No
2、minal value 4 CCITT 36840 Ranges about nominal value r no action need be taken -x to +x readjustment at terminal station sufficient - y to - x and + x to + Y 1 a fault must be assumed +y FIGURE 1/M.530 Typical distribution of observed values of level, showing ranges in which different action is nece
3、ssary Recommendation M.535 SPECIAL MAINTENANCE PROCEDURES FOR MULTIPLE DESTINATION, UNIDIRECTIONAL (MU) GROUP AND SUPERGROUP LINKS The Recommendations covering the maintenance of groups and supergroups will apply as far as possible but there will be a number of new maintenance problems which are pec
4、uliar to multiple destination links. In particular, arrangements will be needed to check the performance of the MU main section of such links. In order to simplify the procedures and minimize interference to other users of the common path, it is recommended that the send reference station (see Figur
5、e 1/M.460) for the MU main section should act as a focal point for reports and inquiries concerning the MU main section. The group, supergroup, etc., control stations will still be responsible for localizing a fault to a particular section of a link in accordance with Recommendation M.130. When a fa
6、ult is found to be in the communication satellite link, the send reference station will report the fault to the satellite control responsible for this link from baseband-in to baseband-out. When the fault is cleared, the send reference station will advise the MU main section controls which will in turn advise the group, supergroup, etc., controls concerned. - 310 Fascicle IV.l - Rec. M.535 1 I
