Patent ID: 7995623

Claim:
A system for mutually synchronizing a first clock signal placed in a first network element and a second clock signal placed in a second network element, said first network element being arranged to transmit synchronizing messages to said second network element, and said second network element being arranged to receive said synchronizing messages, said system comprising: calculation means that is arranged to form a difference value of a synchronizing message, said difference value being essentially a difference of a reception time value and a transmission value of the synchronizing message, said reception time value depending on a cumulated number of periods of the second clock signal at the moment of arrival of the synchronizing message at a predetermined synchronizing point in the second network element, and said transmission value depending on a position of said synchronizing message in a chronological transmission order of the synchronizing messages, and adjusting means that is arranged to adjust the second clock signal in the basis of information contained by difference values corresponding to chronologically successive synchronizing messages, wherein said adjusting means is arranged to weight an adjusting effect of the difference values belonging to a first area of a margin of fluctuation of the difference values more heavily than an adjusting effect of the difference values belonging to a second area of the margin of fluctuation of the difference values, said first area representing smaller difference values than said second area and said first area representing the lowest part of the margin of fluctuation of the difference values.