In a system of control devices networked with one another via a first network or multiple first sub-networks, and of which at least one is a server-based control device that combines multiple functional units, a grandmaster clock is defined by ascertaining the best clock of the entire network. If the best clock is located in a server-based control device, the distances are ascertained between selected functional units that are suitable as a source of the grandmaster clock and selected active network interfaces that connect the server-based control device to the first network or multiple first sub-networks, and the average distance to all selected network interfaces for each of the selected functional units is determined. That selected functional unit that has the smallest average distance to all selected network interfaces is defined as grandmaster clock for the first network or the first sub-networks.

A reference time associated with a satellite signal received at a clock synchronization source is determined, wherein the reference time is from a master reference clock. A recorded time associated with a corresponding satellite signal received at a remote clock synchronization destination is received from the remote clock synchronization destination via a network, wherein the received recorded time is from a remote clock to be synchronized with the master reference clock. A clock adjustment value is calculated based on a comparison of the determined reference time and the received recorded time. The clock adjustment value is provided to the remote clock synchronization destination, wherein the clock adjustment value is able to be utilized by the remote clock synchronization destination to adjust the remote clock to increase synchronization with the master reference clock.

Systems and methods for regaining synchronization between a CMTS core and an RPD, where both the core and the RPD are configured for individual synchronization in a slave configuration to a common grandmaster clock.

In one embodiment, an event processing system includes a clock configured to provide time values, and event processing circuitry, which is configured to generate a confidence level indicative of a degree of confidence of an accuracy of a timestamp, the timestamp being generated for an event responsively to a time value indicative of when an operation associated with the event occurred.

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).

A network measurement device includes a setting control unit that sets, for example, a single GNSS as a transmission source of a signal of a multi-band, a multi-band abnormality detection unit that detects a multi-band reception abnormality based on an existing GNSS antenna receiving a signal in the multi-band transmitted from the GNSS, which is the transmission source, and reception signal information obtained by reception processing in a state in which the network measurement device is connected to the apparatus of a moving destination, for example, a boundary clock, and the existing GNSS antenna is connected to an antenna input terminal, for example, and an alert notification control unit that notifies a user of an alert notification that a multi-band reception abnormality occurs when a multi-band reception abnormality is detected.

A communication method and a communications apparatus are provided. The communication method includes: sending, by a terminal device, a first indication message, where the first indication message is used to indicate a first time type and/or a first time precision, or the first indication message is used to indicate an access network device to send time information to the terminal device; receiving, by the terminal device, the time information; and synchronizing, by the terminal device, a time of the terminal device based on the time information. Correspondingly, a communications apparatus is further provided. According to the embodiments of this application, the terminal device can obtain, based on requirements of different application scenarios, a time type and/or time precision preferred by the terminal 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.

Disclosed is a method for communication, according to a TDMA protocol, between a master device and at least one slave device, during which a plurality of frames are transmitted between the master device and the slave device, each frame being partitioned into a plurality of time intervals, at least one time interval having an analogue synchronization signal having an amplitude regulation portion in the form of a sine wave having a constant amplitude over a number of predetermined pulses, and an optimized synchronization portion in the form of a triangular amplitude modulation of the sine wave so as to determine a reference time.

A method for synchronizing a distributed application includes: transmitting, by an application backend, application data packets to an application frontend; transmitting, by the application backend, a synchronization request packet to the application frontend; retrieving, by the application backend, a backend timestamp from a server clock; retrieving, by the application frontend, a frontend timestamp from a terminal device clock and transmitting the retrieved frontend timestamp to the application backend; calculating, by the application backend, a time offset of the frontend timestamp from the retrieved backend timestamp and using the calculated time offset for synchronization; detecting, by a scheduler, an actual state of a communication connection and transmitting control data to the application backend; and adapting, by the application backend, transmission of synchronization request packets based on the control data indicating jitter of the synchronization request packets preventing the distributed application from being executed synchronously.