Method and device for demapping a tributary recovering lower order synchronism

摘要

In a method of demapping a tributary from a first frame into a second frame, the first frame has a plurality of tributary words and a synchronization word, and first and second counters are provided. The first counter is increased by a first value at each dock cycle of the second frame, and reading operations are performed according to the second counter. Synchronization information, generated according to the synchronization word, is used to change between first and second states. When in the first state, the second counter is synchronized to the first counter at each clock cycle of the second frame; and, when in the second state, the second counter is synchronized to the first counter at a predetermined instant of the second frame, the second counter increasing by a second value at each clock cycle of the second frame wherein the reading operation is performed.