Method and equipment used for restoring reference clock

用于恢复基准时钟的方法和设备。提供设备(21)，恢复由发送器(20)中的主时钟(22)产生的基准时钟。发送器(20)在网络(3)上发送定时数据包。该设备包括可控从属时钟(27)和测定在主时钟和从属时钟之间频率漂移和控制从属时钟(27)以便减少漂移的控制电路(25、26、28)。测定为(r×m×N)-C′a(n+r×m)的函数的误差，公式中C'a(n)=［∑c'(n-i)］/q.N是连续的定时信息项的发送之间主时钟的循环数、C′(s)是从网络接受第(S-rm)和第S定时信息项之间从属时钟的循环数、m是大于零的整数、q是大于1的整数以及r是表示漂移测定的次序的非负的整数。 An apparatus (21) is provided for recovering a reference clock generated by a master clock (22) in a sender (20). The sender (20) sends timing packets over a network (3). The apparatus comprises a controllable slave clock (27) and a control circuit (25, 26, 28) which determines the frequency drift between the master clock and the slave clock and controls the slave clock (27) so as to reduce the drift. The error is determined as a function of ( r × m × N ) - C' a ( n + r × m ), where N is the number of cycles of the master clock between the sending of consecutive timing information items, C' (s) is the number of slave clock cycles between receipt of the (s-rm)th and sth timing information items from the network, m is an integer greater than 0, q is an integer greater than 1, and r is a non-negative integer representing the order of the drift determination.