Tenants in data centers may want access to high precision clocks without having to run their own PTP stacks or reference clocks. Furthermore, different tenants may want their workloads synchronized to their own secured clock domain. PTP, the currently dominant synchronization protocol, allows for only 256 clock domains (CDs). Virtual CDs (vCDs) virtualize the concept of clock domains by maintaining a hardware clock within a host computer, receiving a network clock domain packet that includes a clock domain identifier and an origin timestamp produced by a reference clock, using the network clock domain packet to synchronize the hardware clock to the reference clock, and using the hardware clock to provide a hardware timestamp value to a virtual machine (VM) running on the host computer or to a process running on the host computer, wherein the hardware clock is secured from manipulation by the VM or by the process.

A method for reception of a signal by a subscriber of a real-time network. The signal includes a signal clock having a signal clock frequency and the subscriber includes a counter, which has a counter clock with a counter clock frequency and which maps a local time of the subscriber. The method includes sampling the signal with a reception clock of a reception counter of the subscriber, the reception clock being derived from the counter clock, whereby the reception counter maps the local time of the subscriber, adapting a phase position of the reception clock to a phase position of the signal clock when said reception clock is derived from the counter clock, and sampling the signal at a reception clock frequency of the reception counter

Systems and methods are provided for timing signals, measuring latency, and/or timestamping. Some of the systems described herein can measure latency in a network device, and can include a signal generator, a sampler, a pulse detector, a timer, and a connector. The signal generator can define a signal profile. The sampler can sample the signal profile at a frequency of at least 4 GHz to generate a plurality of bits, each bit corresponding to a value of the signal profile during the sampling. The pulse detector can detect a change in the signal profile by detecting at least one change in the plurality of bits. The timer can time the change in value in the plurality of bits to provide at least one detection time measurement. The connector can electronically link the signal generator and the sampler to the network device to provide an external network path for transmitting a signal from the signal generator to the sampler via the network device.

Examples described herein include systems and methods for performing email synchronization in situations where mobile-device connectivity is lacking. The mobile device can send an SMS message to an email notification server requesting email synchronization and the email notification server can request synchronization with the email server associated with the user's email account. After receiving an email from the email server, the email notification server can encrypt the email and break it into various chunks, with each chunk including a header having identifying information. The chunks can be transmitted as SMS messages to the mobile device. The email application can retrieve the SMS messages, decrypt them, and reconstruct the email. The email application can then display the email for the user.

Provided are a clock synchronization method performed between communication nodes included in a communication network, the clock synchronization method comprises receiving a synchronization source signal through any one of remaining communication nodes except for an uppermost communication node included in the communication network, generating a reference clock for clock synchronization from the received synchronization source signal and transmitting the generated reference clock through a first path including at least a portion reverse to a second path through which a downlink signal is transmitted in the communication network.

A signage player includes: a time function configured to count an internal device time. The signage player also includes a time correction calculator configured to acquire a reference time from the outside, for example, an NTS server, at a timing determined in advance and synchronize the internal device time with the reference time; and a time corrector configured to calculate a time correction coefficient defined using a change rate of a time difference, an error change rate (Δ) between the reference time and the internal device time at a timing different from the timing determined in advance and calculate a corrected time acquired by correcting the internal device time using the time correction coefficient.

A transceiver device includes a transmitter and a receiver connected through first and second lines. A first frame period includes an active period for transmitting a first payload and a vertical blank period including a frequency hopping period. The transmitter transmits, to the first and second lines, signals having a first voltage range in a first mode and signals having a second voltage range in a second mode. The transmitter generates a first horizontal synchronization signal in the second mode except for the frequency hopping period, encodes the first horizontal synchronization signal to horizontal synchronization data, and generates a second horizontal synchronization signal in the first mode in the frequency hopping period. The transmitter adds a first clock training pattern to the horizontal synchronization data except for the frequency hopping period, and adds a second clock training pattern to first horizontal synchronization data after the frequency hopping period.

Present disclosure describes the techniques for regaining synchronization between the RPD and the PTP server, without resetting RPD, in the event of run time-phase jump experienced at RPD. To do so, said technique discloses identifying a run time phase jump event at a remote Physical device (RPD) and initiating an Upstream Channel Descriptor (UCD) refresh procedure to reconnect the RPD with Precision Time Protocol (PTP) server.

A communication apparatus includes a plurality of clocks configured to output signals indicating current times, a plurality of counter units configured to synchronize with the plurality of clocks using the signals indicating the current times output from the plurality of clocks, an instruction unit configured to give an instruction to acquire count values of the plurality of counter units, an acquisition unit configured to acquire the count values of the plurality of counter units based on the instruction from the instruction unit, and a calculation unit configured to calculate a difference between the acquired count values.

The present disclosure provides a signal sampling method and apparatus, and an optical receiver. The method includes sampling a burst signal that is received according to a first sampling frequency to obtain a first sampling signal; sampling a preamble signal in the first sampling signal according to a second sampling frequency to obtain a second sampling signal; determining a phase difference between the burst signal and a local sampling clock corresponding to the first sampling frequency according to the second sampling signal; and interpolating the first sampling signal according to the phase difference to obtain a target sampling signal.