Slave clock

Abstract: Apparatus, system and method for synchronizing one or more clocks across a communication link. A slave clock may be synchronized to a master clock by means of a synchronization signal sent from the master to the slave clock side of the link. The synchronization signal may be an expected signal pattern sent at intervals expected by the slave side. The slave clock may correlate received signals with a representation of the expected synchronization signal to produce a correlation sample sequence at a first sample rate which is related as n times the slave clock rate. The synchronization signal receipt time indicated by the correlation sample sequence may be refined by interpolating the correlation sample sequence around a best correlation sample to locate a best interpolation at an interpolation resolution smaller than the sample resolution. The best interpolation may in turn be further refined by estimating between interpolator outputs adjacent to the best interpolation output. The synchronization signal receipt time thus determined is compared to the expected time based upon the slave clock, which is adjusted until the times match. After initialization, all slave clock errors are preferably accumulated to prevent long-term slip between the slave and master clocks. Formerly independent master and slave clocks synchronized across the communication link constitute a noncommon clock which may be compared on each side of the link to secondary independent clocks, and the secondary independent clocks may then be separately synchronized by adjusting one to have the same difference from its local noncommon clock as the secondary clock on the other side of the link has from its local noncommon clock.

Abstract: A method and system for synchronizing clocks in a packet network that includes a master node and at least one slave node that communicate with one another is disclosed. A timer value from a master clock is retrieved upon transmission of a first packet to the slave node. The timer value and an associated code are subsequently sent to the slave node in a subsequent packet. After receiving the first packet, the slave node, retrieves a timer value from a slave clock and associates it with an identifying code of the first packet. After receiving the subsequent packet, the slave node relates the timer values and adjusts a clock value of the slave clock accordingly. An interrupt scheme may be used to implement the retrieval of the timer values.

Abstract: Apparatus includes at least two devices that communicate with each other, wherein a first one of the at least two devices having an IEEE 1588 precision time protocol interface, the interface including one or more components configured for communications in both a wired manner and a wireless manner with a second one of the at least two devices. The second one of the at least two devices having an IEEE 1588 precision time protocol interface, the interface including one or more components configured for communications in both a wired manner and a wireless manner with the first one of the at least two devices. Wherein one of the at least two devices includes a master clock and the other one of the at least two devices includes a slave clock, wherein the master clock communicates a time to the slave clock and the slave clock is responsive to the communicated time from the master clock to adjust a time of the slave clock if necessary to substantially correspond to the time of the master clock, thereby time synchronizing the at least two devices together.

Abstract: A method for synchronizing the times of a master clock provided in the master station and slave clocks provided in the slave stations in a data transmission and receiving system consisting of the master station as a data transmission control station and slave station and/or stations for two-way data transmission. An encoded time survey command including master clock time is transmitted from the master station to each slave station. This is followed by an encoded response from each slave station which includes the slave clock time, from which the transmission delay to and from the slave station is determined along with the time difference between master and slave clocks. Time correction data is then transmitted to correct the time of the slave station clock.