Time synchronization device, time synchronization system, and time synchronization method
In order to simplify calculation of delay time lengths in a time synchronization device in a packet network, when executing time synchronization using a synchronization signal sent via the packet network, this time synchronization device 20 includes: a data receiving unit 21 that receives synchronization information including a time correction field used when correcting synchronization time information in a client device 30 ; a before-data-processing time correcting unit 22 that updates the time correction field by subtracting information indicating a time at which synchronization information is received, from the time correction field; an after-data-processing time correcting unit 23 that updates the time correction field by adding information indicating a time after performing data processing on the synchronization information, to the time correction information of the time correction field updated by the before-data-processing time correcting unit 22 ; and a data sending unit 24 that sends the updated synchronization information to the client device 30.
1. A time synchronization method comprising:
generating, using a time standard device, time information;
generating, using a client device, synchronization time information synchronized with the time information generated in the time standard device;
relaying, between the time standard device and the client device, synchronization information including a time correction field used when the synchronization time information is corrected;
receiving a packet data comprising the synchronization information sent from the time standard device;
determining whether the received packet data comprises the synchronization information;
updating the time correction field by subtracting information indicating a time at which the synchronization information is received, from time correction information set in the time correction field;
updating the time correction field by adding information indicating a time after performing data processing on the synchronization information, to the time correction information in the time correction field; and
sending, to the client device, the synchronization information whose time correction field is updated.
2. The time synchronization method according to claim 1 , comprising:
reproducing a frequency used in the time standard device, by using the synchronization information sent from the time standard device; and
generating information indicating a time, used in updating the time correction field, by using the reproduced frequency.
3. The time synchronization method according to claim 2 , wherein in reproducing the frequency, the frequency is reproduced by using a time stamp of the synchronization information sent as a packet.
4. The time synchronization method according to claim 2 , wherein in reproducing the frequency, the frequency is reproduced by using the time information transmitted via a physical layer and generated in the time standard device.
5. A time synchronization method comprising:
receiving a data packet comprising synchronization information sent from a time standard device, the synchronization information including a time correction field used when correcting synchronization time information generated so as to synchronize with time information generated in the time standard device;
determining whether the received packet data comprises the synchronization information;
updating the time correction field by subtracting information indicating a time at which the synchronization information is received, from time correction information set in the time correction field;
updating the time correction field by adding information indicating a time after performing data processing on the synchronization information, to the time correction information of the updated time correction field; and
sending, to a client device, the synchronization information whose time correction field is updated.
6. The time synchronization method according to claim 5 , further comprising:
reproducing a frequency used in the time standard device, by using the synchronization information sent from the time standard device, after receiving the synchronization information; and
providing information indicating a time, used in updating the time correction field, by using the reproduced frequency.
7. The time synchronization method according to claim 6 , wherein
in reproducing the frequency, the frequency is reproduced by using a time stamp of the synchronization information sent as a packet.
8. The time synchronization method according to claim 6 , wherein
in reproducing the frequency, the frequency is reproduced by using the time information transmitted via a physical layer and generated in the time standard device.
9. The time synchronization method according to claim 5 , further comprising:
asynchronously generating information indicating a time, used in updating the time correction field, with time information generated in the time standard device.