A time synchronization mechanism is provided for reducing influences of link asymmetry between time synchronization devices. A second transmission device 2 includes: a transmission section 16 configured to transmit packets for delay calculation for a plurality of wavelengths to the corresponding time transmission device simultaneously; and a reception section 17 configured to calculate a propagation delay Dms on a path from the corresponding time transmission device to the second transmission device 2 based on a difference between the arrival times of the packets for delay calculation for the plurality of wavelengths received from the corresponding time transmission device, receive a propagation delay Dsm on a path from the second transmission device 2 to the corresponding time transmission device calculated by the corresponding time transmission device, and calculate a propagation delay Dmax that is larger than any of the propagation delay Dms and the propagation delay Dsm. The reception section 17 transmits a received PTP packet to a slave node 4 after waiting for a waiting delay Wms that is calculated by subtracting the propagation delay Dms from the propagation delay Dmax.

A method for a distributed clock system (DCS) device that includes receiving a GPS signal, determining that a first current time equals a predetermined start time, and generating a shifted GPS signal by applying a configurable delay to the received GPS signal, the shifted GPS signal alternating between a low value and a high value. The method includes responsive to a falling edge of the shifted GPS signal, generating an ARM signal having a rising edge after a falling edge of the shifted GPS signal, and responsive to the ARM signal being high and the shifted GPS signal being high, generating an output enable signal. The method includes transmitting, while the output enable signal is high, a triggering signal, the triggering signal having one or more synchronizing pulses that cause one or more sampling devices to sample data according to the frequency associated with the raw clock signal.

An electronic timepiece includes a storage that stores specific-region DST application rule information and local time information that includes, in association with each other, DST application rules for each region and standard-wave transmitting station information indicating each station transmitting standard waves receivable in the region; a processor that controls clock time to be kept by a clock circuit and displays time to be displayed on a display; and a standard wave receiver that receives standard waves and obtains time information. The processor calibrates the clock time based on the time information indicated by the standard waves received by the standard wave receiver, and controls the display time based on whether the specific-region DST application rule information and the DST application rule information associated with the standard-wave transmitting station information indicating a station transmitting the received standard waves satisfy a predetermined condition.

[Problem] An object is to obtain a time quality of another GM with high accuracy on the basis of a GM a time quality of which is known already.

[Solution] A first TC 20 includes a time comparison unit 23 that calculates time difference information by comparing first time information of a first PTP processing unit 12 and second time information of a second PTP processing unit 22 with each other. In addition, a quality calculation device 5 measures time difference information until time difference information obtained by a time comparison unit 23 of the first TC 20 and time difference information obtained by a time comparison unit 43 of a second TC 40 match each other, and obtains a GM time quality of a second GM 30 on the basis of a transmission time error of the time transmission network 2 at a timing when both of pieces of the time difference information match each other.

To provide a measurement apparatus that can acquire measurement date/time information without having a clock in a measurement unit. A health information management system includes a blood pressure monitor that measures blood pressure information and includes an RTC that can acquire the count value at the time of each measurement, and a smart phone including a clock unit that can acquire date/time information, and the health information management system can perform at least information transmission from the blood pressure monitor to the smart phone. The measurement date/time of blood pressure information is specified based on a difference between the count value at the time of measurement and the count value at the time of information transmission from the blood pressure monitor to the smart phone, and date/time information acquired by the smart phone from the clock unit.

A time synchronization method that is capable of selecting whether synchronization, by a timepiece unit that generates a time signal synchronized with a standard time and outputs it to an exterior, with the time is performed by time information obtained by receiving a radio wave including information relating to the time, or is performed by means of a holdover performed using a clock signal from an internal or external clock source. A schedule having a first time period in which the above-mentioned time information is used, and a second time period by means of the holdover is determined according to temporal reception characteristics of the radio wave at a reception location of the radio wave, and according to the schedule, supplying the timepiece unit with the time information or supplying the timepiece unit with the clock signal from the internal or external clock source.

A time synchronization method that is capable of selecting whether synchronization, by a timepiece unit that generates a time signal synchronized with a standard time and outputs it to an exterior, with the time is performed by time information obtained by receiving a radio wave including information relating to the time, or is performed by means of a holdover performed using a clock signal from an internal or external clock source. A schedule having a first time period in which the above-mentioned time information is used, and a second time period by means of the holdover is determined according to temporal reception characteristics of the radio wave at a reception location of the radio wave, and according to the schedule, supplying the timepiece unit with the time information or supplying the timepiece unit with the clock signal from the internal or external clock source.

[Problem] To reduce a total equipment cost.

[Solution] A local device (20A) of a time synchronization system (10A) includes a path switching unit (33) that connects respective remote devices (40A1 to 40An) using individual optical fibers (60a to 60n) and switches the respective optical fibers (60a to 60n) sequentially in a cyclic order, a counter unit (31), a phase difference memory unit (30), and a table unit (32). The counter unit (31) counts a pulse signal P1d demodulated by a PPS demodulation unit (23) to obtain a count value (T1). The phase difference memory unit (30) stores the count value (T1) as path information in association with a phase difference (φ1) detected by a phase detection unit (22), and outputs, when the count value (T1) is input, the phase difference (φ1) associated with this path information indicated by the count value (T1) to the variable delay unit (24). When the count value (T1) is input, the table unit (32) outputs a path switching signal (K) for switching to the next optical fiber (60n) in the cyclic order to the path switching unit (33) and the path switching unit (33) performs switching to the next optical fiber (60n).

An electronic timepiece includes a clocking means configured to clock time, a switch configured to accept an input, and a processor configured to measure a period during which the switch is accepting an input, determine in accordance with a result of the measurement whether to change time difference data set in the electronic timepiece, and correct the time clocked by the clocking means on the basis of the time difference data.

An electronic timepiece includes a clocking means configured to clock time, a switch configured to accept an input, and a processor configured to measure a period during which the switch is accepting an input, determine in accordance with a result of the measurement whether to change time difference data set in the electronic timepiece, and correct the time clocked by the clocking means on the basis of the time difference data.