A sensor control circuit periodically transmits packets in synchronism with a one-by-one monotonous change in count values from a real-time clock circuit. The count values repeat the change within a predetermined numerical value range. The sensor control circuit transmits the count values by adding them to the packets. A collection control circuit acquires values of a reference clock synchronized with a reference time of an upper network from a reference clock generation circuit in accordance with reception of the packets, stores the values in a storage circuit as time stamps representing arrival times of the packets, performs statistical processing of the time stamps and the count values concerning the packets received, and corrects the time stamps based on an packet transmission interval and a reference arrival time representing the arrival time of a head packet, which are obtained from the statistical processing.

A communication system (1000) includes communication devices (10, 20) to share common time after correction of synchronization error including a communication delay with each other via a network (400). The communication device (10) includes a set time acquirer to acquire set time set by a user, a setter to set the set time as first system time, which is system time of the communication device (10), and a time difference data transmitter to transmit time difference data, which indicates a time difference between the common time and the set time, to the communication device (20). The communication device (20) includes a time difference data receiver to receive the time difference data, and a setter to set the sum of the common time and the time difference indicated by the time difference data as second system time, which is system time of the communication device (20).

Systems and methods that provide for transmission of messages among nodes (e.g., acceleration components configurable to accelerate a service) using a time-synchronized transport layer (TSL) protocol are provided. An example method, in a network comprising at least a first node, a second node, and a third node, includes each of the at least the first node, the second node, and the third node synchronizing a respective clock to a common clock. The method further includes each of the at least the first node, the second node, and the third node scheduling data transmission in the network in a manner such that at a particular time in reference to the common clock each of the at least the first node, the second node, and the third node is scheduled to receive data from only one of the first node, the second node, or the third node.

A method for synchronizing a timing end application (TEA) in an edge communication network includes (a) receiving, at a first access device, a time stamp from a first TEA communicatively coupled to the first access device, (b) transmitting the time stamp from the first access device to a second access device via communication media of the edge communication network, (c) adjusting the time stamp to account for transit time of the time stamp from the first access device to the second access device, and (d) after adjusting the time stamp, transmitting the time stamp from the second access device to a second TEA communicatively coupled to the second access device.

A communication system (1000) includes communication devices (10, 20) to share common time after correction of synchronization error including a communication delay with each other via a network (400). The communication device (10) includes a set time acquirer to acquire set time set by a user, a setter to set the set time as first system time, which is system time of the communication device (10), and a time difference data transmitter to transmit time difference data, which indicates a time difference between the common time and the set time, to the communication device (20). The communication device (20) includes a time difference data receiver to receive the time difference data, and a setter to set the sum of the common time and the time difference indicated by the time difference data as second system time, which is system time of the communication device (20).

This disclosure describes methods and systems to for a method for a first computing node to receive frequency information of a system clock. The first computing node receives the frequency information of the system clock from a second computing node at a physical layer of a connection between the first computing node and the second computing node. The first computing node also receives a message from the second computing node at above the physical layer of the connection between the first computing node and the second computing node. The message includes an attestation of the frequency information from which the first computing node may verify that the second computing node is a trusted source of the frequency information.

Example systems, apparatus, and methods receive audio information including a plurality of frames from a source device, wherein each frame of the plurality of frames includes one or more audio samples and a time stamp indicating when to play the one or more audio samples of the respective frame. In an example, the time stamp is updated for each of the plurality of frames using a time differential value determined between clock information received from the source device and clock information associated with the device. The updated time stamp is stored for each of the plurality of frames, and the audio information is output based on the plurality of frames and associated updated time stamps. A number of samples per frame to be output is adjusted based on a comparison between the updated time stamp for the frame and a predicted time value for play back of the frame.

Time stamp replication within wireless networks is described. In an embodiment, a wireless station receives an input time stamp and uses this input time stamp to generate an output time stamp. The wireless station transmits the output time stamp to wireless stations in one of a number of groups which make up the wireless network. The output time stamp is generated to compensate for delays between receiving the input time stamp and transmitting the output time stamp such that output time stamp which is transmitted at a time T corresponds to the value that the input time stamp would have had if it had been received at time T (and not at a time earlier than T). This may, therefore, reduce or eliminate independent time stamp errors and jitter caused by multiple disparate systems and processes.

According an aspect of the present invention, a data receiving apparatus includes a calculator. The calculator (1) stores a date and time indicated by the clock unit in association with a first local date and time in the memory as a reference date and time, when the packet includes first date-and-time data indicating the first local date and time and information indicating that the first date-and-time data can be used for date and time association, and (2) calculates, when the packet includes sensor data and second date-and-time data indicating a second local date and time associated with the sensor data, a third date and time based on a difference between the first local date and time and the second local date and time, and on the reference date and time.

A method includes, at a first node: transmitting a first calibration signal at a first time-of-departure measured by the first node; and transmitting a second calibration signal at a second time-of-departure measured by the first node. The method also includes, at a second node: receiving the first calibration signal at a first time-of-arrival measured by the second node; and receiving the second calibration signal at a second time-of-arrival measured by the second node. The method further includes: defining a first calibration point and a second calibration point in a set of calibration points, each calibration point comprising a time-of-departure and a time-of-arrival of each calibration signal; calculating a regression on the set of calibration points; and calculating a frequency offset between the first node and the second node based on the first regression.