An industrial system for controlling backplane communication, including: a cluster manager including a primary switch linked to a primary control module, at least one Input/Output, I/O, module including a secondary switch linked to a secondary control module, a unidirectional communication line linking the cluster manager to the at least one IO module through passive base plates, wherein the cluster manager includes a transmission port and a reception port on the unidirectional communication line and the at least one Input/Output module includes a reception port on the unidirectional communication line, wherein the primary control module is configured to generate a pulse via the transmission port on the unidirectional communication line, wherein, upon reception of the pulse, the primary control module is configured to create a primary timestamp from a primary clock of the primary switch and the secondary control module is configured to create a secondary timestamp from a secondary clock of the secondary switch, wherein the primary control module is configured to send a message via the transmission port on the unidirectional communication line to the secondary control module, the message including the primary timestamp, wherein, upon reception of the message, the secondary control module is configured to synchronize the secondary clock with the primary clock based on the received primary timestamp and secondary timestamp.

Method for time synchronization in a network comprising masters and at least one slave. The slave receives synchronization messages from the masters via the network for time synchronization of a first clock and a second clock of the slave. A first master sends a first synchronization message having a first time stamp to the slave for time synchronization of the first clock. The slave calculates a clock rate and a time difference between the first clock and the first master and aligns the first clock with a synchronized time. A second master sends a second synchronization message having a second time stamp to the slave for the time synchronization of the second clock. The clock rate of the second clock is set to the first clock rate. A time difference between the second clock and the second master is calculated and the second clock is aligned with the synchronized time.

According to one embodiment, there is provided a multiplexing method including: receiving a TS over IP packet from a plurality of encoders which are disposed at physically remote places, or which are disposed in a virtual environment on a cloud computing system where physical locations are unidentifiable; performing multiplexing after compensating for a delay and jitter of a transmission path, based on a timestamp which is stamped on an RTP header of the TS over IP packet; and performing, with respect to a PCR packet, either multiplexing after compensating for the delay and the jitter, based on a time re-generated in a multiplexing apparatus, or multiplexing by generating a PCR packet in the multiplexing apparatus.

A time-point synchronization apparatus (10) includes a time-point management unit (144), a time-gap counter (145), and a time-gap calculation unit (142). The time-point management unit (144) manages an apparatus time point equivalent to a current time point. The time-gap counter (145) records a time gap which is a different between a time point indicated in reception information and the apparatus time point. When a frequency in the time-gap counter (145), corresponding to the time gap corresponding to a latest reception time point corresponding to latest reception information is treated as the highest among all of frequencies indicated in the time-gap counter (145), the time-gap calculation unit (142) synchronizes the apparatus time point to the latest reception time point.

Network devices that (a) test that GPS-clock enabled network devices have synchronized clocks, (b) identify non-GPS-clock enabled network devices with symmetric latencies as likely to be synchronized to GPS-clock enabled neighbor devices, (c) determine clock skews of remaining network devices not identified in (a) or (b) against the network devices identified in (a) and (b), and re-evaluate latencies of the GPS-clock enabled network devices, the non-GPS-clock enabled network devices, and the remaining devices based on the results of (a)-(c).

An example system comprising a first transceiver configured to receive a request airframe from a second transceiver over a wireless link, the request airframe including a first time indication indicating a first time TS1, a second time indication indicating a second time TS2 that the request airframe was received, generate a respond airframe and including a third time indication indicating a third time TS3 that the respond airframe is transmitted to the second transceiver, transmit the respond airframe to the second transceiver, provide a timestamp information request to second transceiver, receive a timestamp information response, the timestamp information response including a fourth time indication indicating a fourth time TS4, calculate a counter offset using the first time, second time, third time and fourth time as follows: $\mathrm{counter}\mathrm{offset}=\frac{\left(\mathrm{TS}1+\mathrm{TS}4-\mathrm{TS}3-\mathrm{TS}2\right)}{2},$
calculate a phase offset based on the counter offset, and correct a phase of the first transceiver.

The present application discloses a method for determining time information, including: detecting a signal of a periodic block, and recording a timestamp of the periodic block; and determining a time at which a time information message to be sent according to the timestamp of the periodic block matched with the time information message, and generating a timestamp of the time information message. The present application further discloses an apparatus and device for determining time information, and a storage medium.

A method for calculating a communication time between a first and second devices includes: adding, to a first packet, first timer information indicating an elapsed time from activation of the first device, and transmitting the first packet; transmitting notification information including the first timer information and second timer information indicating an elapsed time from activation of the second device; transmitting a second packet including the first and second timer information, third timer information indicating an elapsed time from activation of the second device, and first time information indicating a time in the second device; and calculating a communication time from the first device to the second device based on the first timer information, the second timer information, the third timer information, and the first time information, fourth timer information indicating an elapsed time from activation of the first device, and second time information indicating a time in the first device.

To improve integrity of time synchronization, a node in the safety rated system takes steps to ensure the time to which it is synchronized has not become corrupted. The node receives a synchronize request message from an adjacent network device, which includes the master time, and the node generates an offset value corresponding to a difference between a local time and the master time. The node stores the offset time into a safety memory to ensure that the offset value has data integrity and does not become corrupted. The node performs periodic skew detection between two devices to verify that the clocks remain synchronized. In addition, the node performs a local drift detection to detect if the frequency of the local oscillator on which the local clock value is based begins to change.

This disclosure contributes a Unified Clock which utilizes frequency alignment throughout network nodes for accurate time stamping and direct elimination of nodes residence delays from times originated in Grand Master (GM) and propagated downstream with PTP messages, wherein downstream slave nodes are maintaining local slave time (LST) delayed to the GM time by downstream links delays only and such links delays are estimated separately and added to the LST in order to derive Local Master Time (LMT) corresponding to the GM time.