1. that the fraction of time during which a preselected threshold is exceeded in the worst month of a year is referred to as “the annual worst-month time fraction of excess”;
2. that the statistic relevant for the performance criteria referring to “any month” is the long-term average of the annual worst-month time fraction of excess;
3. that the worst month of a year for a preselected threshold for any performance degrading mechanism, be that month in a period of twelve consecutive calendar months, during which the threshold is exceeded for the longest time. The worst month is not necessarily the same month for all threshold levels.
Note – Recommendation ITU-R P.841 presents a model for the conversion of the average annual time fraction of excess to the average annual worst-month time fraction of excess. Global values of the parameters of this model are given, as well as more detailed values for several regions of the world.
* Radiocommunication Study Group 3 made editorial amendments to this Recommendation in 2000 in accordance with Resolution ITU-R 44.