[Problem] To synchronize timings of transmitting and receiving a pulse signal (1 PPS signal) at a constant interval between communication apparatuses even in a case where an optical fiber connecting the communication apparatuses fluctuates in an optical characteristic and an optical fiber length. [Solution] The time synchronization system 20 transmits and receives a pulse signal at a constant interval between a local apparatus L (apparatus L) and a remote apparatus R (apparatus R) connected through the two-core bidirectional optical fibers F1 and F2 to synchronize time. A propagation delay amount τ1 in the fiber F1 is calculated, from a proportional relationship between T1 and T2 and a proportional relationship of τud and τ1, where T1 represents a propagation delay time difference between a pulse signals P1 and P4 of an identical wavelength λ.sub.1 returned after transmitting a pulse signal P1 of wavelength λ.sub.1 and a pulse signal P2 of wavelength λ.sub.2 different from λ.sub.1 to the remote apparatus R, T2 represents a propagation delay time difference between the pulse signal P1 of wavelength λ.sub.1 and a pulse signal P3 of wavelength λ.sub.2, and τud represents the round-trip delay time between the apparatuses L and R. The pulse signals P1 and P2 are transmitted with a time difference td corresponding to a difference between the current and last calculated propagation delay amounts τ1 being set so that the difference is zero.

[Problem] It is possible to improve the quality of time information by suppressing a jump in time which arises when switching a transfer path in a BC apparatus to which transfer paths of time information of at least 2 systems are connected to an input side. [Solution] A time synchronization apparatus 20 is mounted on a BC apparatus 12c in which two systems of at least a 0-system route (0-system) and a 1-system route (1-system) are connected to an input side, and includes a time correction value holding unit 26 configured to hold a 0-system correction value in which a time error resulting from delay of UTC due to performance inherent to the BC apparatus is the same value as a time error accumulated on the 0-system side and a 1-system correction value in which the time error is the same value as a time error accumulated on the 1-system side. Further, a failure restoration detection unit 23 configured to detect a failure in the 0-system or the 1-system, a time calculation unit 24 configured to perform correction by subtracting a 1-system correction value relating to a normal 1-system from UTC having time error accumulated on the normal 1-system side, when a failure in the 0-system is detected, and a path switching unit 25 configured to switch to the normal 1-system side such that the UTC after correction is transferred, when the failure is detected, are included.

A local device of a time synchronization system includes a path switching unit that connects respective remote devices using individual optical fibers and switches the respective optical fibers sequentially in a cyclic order, a counter unit, a phase difference memory unit, and a table unit. The counter unit counts a pulse signal P1d demodulated by a PPS demodulation unit to obtain a count value. The phase difference memory unit stores the count value as path information in association with a phase difference detected by a phase detection unit, and outputs the phase difference associated with this path information indicated by the count value to the variable delay unit. When the count value is input, the table unit outputs a path switching signal for switching to the next optical fiber in the cyclic order to the path switching unit and the path switching unit performs switching to the next optical fiber.

A system for managing a time reference includes a real-time clock, an interface, and a processor. The real-time clock store an RTC time. The interface is configured to receive a GPS time and a cellular time. The processor is configured to: indicate to start a time-speed adjustment loop; determine a true time based at least in part on the GPS time and the cellular time; determine an error between the true time and the RTC time; determine an RTC speed calibration adjustment based at least in part on the error; and adjust the real-time clock speed based at least in part on the RTC speed calibration adjustment.

A system for managing a time reference includes a real-time clock, an interface, and a processor. The real-time clock store an RTC time. The interface is configured to receive a GPS time and a cellular time. The processor is configured to: indicate to start a time-speed adjustment loop; determine a true time based at least in part on the GPS time and the cellular time; determine an error between the true time and the RTC time; determine an RTC speed calibration adjustment based at least in part on the error; and adjust the real-time clock speed based at least in part on the RTC speed calibration adjustment.

A time-synchronization system according to the present disclosure includes a relay apparatus (10) configured to perform time-synchronization with a master apparatus (30) through a transmission system of which a transmission delay changes depending on a transmission direction, and a relay apparatus (20) configured to perform time-synchronization with the relay apparatus (10), in which the relay apparatus (20) transmits information about a difference between first time information obtained by performing time-synchronization with the relay apparatus (10) and second time information obtained from a time-synchronization source to the relay apparatus (10), and the relay apparatus (10) corrects third time information obtained by performing time-synchronization with the master apparatus (30) by using the information about the difference, and performs time-synchronization with a slave apparatus (50) by using the corrected third time information.

A time providing method includes: by a computer, upon receiving data from a device, estimating a generation time of the data using a reception time of the data and a first delay time of the device previously estimated; providing information indicating the generation time to the data; and transmitting the data provided with the information indicating the generation time to a destination of the data.

An electronic device includes a memory; a first processor; a second processor for which power consumption is lower than power consumption of the first processor; a communicator that communicates with an external device; and a switch that switches a connection destination of the communicator to the first processor or the second processor. The second processor is configured to, in a case in which a condition for transitioning to a power suppression state that is an operating state in which power consumption is suppressed is satisfied, connect the communicator by the switch. The first processor is configured to, in a case in which a condition for transitioning to a normal state that is a normal operating state is satisfied, connect the communicator by the switch.

A wireless parking meter with an improved antenna location is described. The antenna may be located within a covering protruding from the top of the parking meter, allowing radio frequency (RF) signals to be transmitted through a portion of the parking meter with high permittivity to the RF signals. Additionally or alternatively, the antenna may be located within the parking meter housing above a lower parking meter mechanism housing so that RF signals can be transmitted through the dome covering of the parking meter, which may have a high permittivity to the RF signals.

The present invention relates to a satellite antenna integrated time-synchronization device for generating a time-synchronization signal from a satellite signal received from a satellite, which includes a case, a 1PPS synchronization module which is disposed in the case and is configured to generate at least a 1PPS signal from the satellite signal, and a signal processing means which is disposed in the case and is configured to generate an IRIG signal and communication data using the 1PPS signal input from the 1PPS synchronization module.