Clock Setup Over a Network

• US 20090028006A1
• Filed: 07/25/2007
• Published: 01/29/2009
• Est. Priority Date: 07/25/2007
• Status: Active Grant

• Current Assignee: Computime Electronics Company Limited
• Original Assignee: Computime Electronics Company Limited
• Inventors: Ha, Wai-leung, Lei, Kairy Kai
• Granted Patent: US 7,948,833 B2
• Time in Patent Office: Days
• US Class Current: 368/46
• CPC Class Codes: G04G 5/00 Setting, i.e. correcting or changing, the time-indication radio-controlled time-pieces G04R
• CPC Class Codes: G04G 7/00 Synchronisation radio-controlled time-pieces G04R
• CPC Class Codes: G06F 1/14 Time supervision arrangements, e.g. real time clock

Abstract

The present invention provides apparatuses and methods for updating a target device from a clock device through a network. The clock device obtains a time value from a clock source and sends the time value to a target device. A node within the network determines a time delay, adjusts the time value in accordance with the time delay, and sends the adjusted time value to the target device. The node may determine a time delay from an internal timer or from a measurement message when adjusting the time value. The clock device may send a subsequent time update message to the target device if the target device does not acknowledge reception of a time update. The clock device may also send a time update message to a target device when a status change of daylight savings time occurs and obtain a subsequent time value from a clock source.

Claims

1. A system comprising:

a clock device configured to;

obtain a time value from a clock source; and

send the time value to a target device over a network; and

a first node configured within the network and configured to;

determine a first network time delay from the clock device to the first node;

adjust the time value by a first network time delay to obtain an adjusted time value; and

send the adjusted time value to a target device, wherein the target device is separate from the network.

2. The system of claim 1, further comprising:

the target device configured to;

obtain the adjusted time value; and

synchronize an internal clock to the adjusted time value.

3. The system of claim 1, further comprising:

a second node configured within the network and configured to;

obtain the adjusted time value from the second node;

determine a second network time delay from the first node to the second node;

further adjust the adjusted time value by the second network time delay; and

forward the adjusted time value to the target device.

4. A method comprising:

(a) obtaining a time value from a clock source;

(b) sending the time value to a target device over a network; and

(c) determining, by a network entity, an adjusted time value from the time value in accordance with a network delay.

5. The method of claim 4, further comprising:

(d) synchronizing an internal clock to the adjusted time value.

6. The method of claim 4, further comprising:

(d) including an indicator in a time update message that the time update message corresponds to a real time update, the time update message containing the time value.

7. The method of claim 4, further comprising:

(d) further adjusting the adjusted time value in accordance with a further network delay.

8. The method of claim 7, further comprising:

(e) repeating (d) until a time update message is received by the target device, the time update message containing the adjusted time value.

9. The method of claim 4, further comprising:

(d) receiving another time value every predetermined time duration.

10. The method of claim 4, further comprising:

(d) receiving another time value when an occurrence of a predetermined type of event is detected at the clock source.

11. The method of claim 4, further comprising:

(d) receiving another time value from the clock source when instructed by the target device.

12. The method of claim 4, further comprising:

(d) determining the network delay from a time stamp in a time update message containing the time value.

13. The method of claim 4, further comprising:

(d) determining the network delay from a measurement message before sending the time value.

14. The method of claim 4, further comprising:

(d) determining the network delay from an internal timer at a node in the network.

15. The method of claim 4, further comprising:

(d) compensating the time value for processing a signal from the clock source.

16. The method of claim 4, further comprising:

(d) converting the time value for a time zone that the target device is located.

17. The method of claim 8, further comprising:

(f) adjusting the adjusted time value only when an indicator is included in the time update message.

18. The method of claim 4, further comprising:

(d) receiving a clock update request from the target device over the network;

(e) in response to (d), obtaining a subsequent time value from the clock source; and

(f) sending the subsequent time value to the target device over the network.

19. The method of claim 4, further comprising:

(d) if the target device does not confirm reception of a time update, obtaining a subsequent time value from the clock source;

(e) sending the subsequent time value to the target device over the network; and

(f) repeating (d)-(e) until the target device confirms the reception of the time update.

20. The method of claim 4, further comprising:

(d) when a status change of daylight savings time occurs, obtaining a subsequent time value from the clock source;

(e) sending the subsequent time value to the target device over the network; and

(f) repeating (d)-(e) until the target device confirms a reception of the subsequent time value.

26. The method of claim 11, further comprising:

(e) initiating (d) when an event is detected at the target device.

27. The method of claim 26, wherein the event corresponds to a power outage.

21. An apparatus comprising:

an acquisition circuit configured to receive a signal from a clock source;

a processor configured to process the signal to obtain a time value from the signal without maintaining a real-time clock and to compensate the time value for a time delay associated with processing the signal; and

a network interface configured to send the time value to a target device over a network.

22. The apparatus of claim 21, the acquisition circuit configured to receive the signal over a radio channel.

23. The apparatus of claim 21, the acquisition circuit configured to receive the signal over an Internet connection.

24. The apparatus of claim 21, the network interface configured to interface to a wired network.

25. The apparatus of claim 21, the network interface configured to interface to a wireless network.