Method for the clock synchronization of a plurality of modules

• US 9,876,597 B2
• Filed: 01/19/2016
• Issued: 01/23/2018
• Est. Priority Date: 01/11/2011
• Status: Active Grant

• Current Assignee: Unify Patente GmbH & Co. KG (Atos Se)
• Original Assignee: Unify GmbH & Co. KG (Atos SE)
• Inventors: Lindner, Thomas
• Primary Examiner(s): Skripnikov, Alex
• Application Number:
  US15/000,290
• Publication Number:
  US 20160142168A1
• Time in Patent Office: 735 Days
• Field of Search: None
• CPC Class Codes: H04J 3/0602 Systems characterised by the synchronising information used
• CPC Class Codes: H04J 3/0638 Clock or time synchronisation among nodes; Internode synchronisation synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43
• CPC Class Codes: H04J 3/0644 External master-clock
• CPC Class Codes: H04J 3/1688 the demands of the users being taken into account after redundancy removal, e.g. by predictive coding, by variable sampling reducing bandwidth of signals in general H04B1/66; in PCM-systems H04B14/046; removal of redundancy in telegraph communication H03M7/30
• CPC Class Codes: H04L 7/08 the synchronisation signals recurring cyclically

Abstract

A method or an arrangement for the clock synchronization of a plurality of distributed modules of an information or communication system where said modules are coupled via a packet-switched network is adapted so that at least two of said modules are controlled by a local clock generator of the modules using an adjustable frequency, and a clock signal is transmitted via the network in the form of clock signal packets. One of said at least two modules takes over the function of a master module, and all remaining modules synchronize the local clock of the modules with the clock of the master module.

Claims

1. A method for clock synchronization of a plurality of distributed modules in an information system or a communications system, said modules being coupled via a network, the modules comprising a master module and at least one slave module, the at least one slave module comprising a first slave module and a second slave module, the method comprising:

the first slave module determining a measurement for a deviation of a local clock generator of the first slave module relative to a clock generator of the master module, the measurement being determined from a comparison of a first clock signal received from the master module to a clock signal of the local clock generator of the first slave module; and

the first slave module using the determined measurement for the deviation of the local clock generator of the first slave module relative to the clock generator of the master module to control the local clock generator of the first slave module to synchronize the local clock generator of the first slave module to the clock generator of the master module;

the first slave module sending a second clock signal via the network in a first time window, the second clock signal being synchronous with a local clock of the local clock generator of the first slave module, the first time window being a time window that is different from time windows used for other clock signals of other slave modules;

the second slave module determining a measurement for a deviation of a local clock generator of the second slave module relative to the clock generator of the master module, the measurement for the deviation of the local clock generator of the second slave module being determined from a comparison of the first clock signal received from the master module to a clock signal of the local clock generator of the second slave module; and

the second slave module using the determined measurement for the deviation of the local clock generator of the second slave module relative to the clock generator of the master module to control the local clock generator of the second slave module to synchronize the local clock generator of the second slave module to the clock generator of the master module;

the second slave module sending a third clock signal via the network in a second time window, the third clock signal being synchronous with a local clock of the local clock generator of the second slave module, the second time window being a time window that is different from the first time window and being different from time windows used for other clock signals of other slave modules.

2. The method of claim 1, wherein the first clock signal is transported via the network at a higher priority as compared to other data packets transmitted via the network.

3. The method of claim 1, wherein the at least one slave module comprises a third slave module, the method comprising:

the third slave module determining a measurement for a deviation of a local clock generator of the third slave module relative to the clock generator of the master module, the measurement for the deviation of the local clock generator of the third slave module being determined from a comparison of the first clock signal received from the master module to a clock signal of the local clock generator of the third slave module; and

the third slave module using the determined measurement for the deviation of the local clock generator of the third slave module relative to the clock generator of the master module to control the local clock generator of the third slave module to synchronize the local clock generator of the third slave module to the clock generator of the master module;

the third slave module sending a fourth clock signal via the network in a third time window, the fourth clock signal being synchronous with a local clock of the local clock generator of the third slave module, the third time window being a time window that is different from the first time window, is different from the second time window, and is different from time windows used for other clock signals of other slave modules.

4. The method of claim 1, wherein the network is configured to utilize a Pulse Code Modulation method to convert analog signals into digital signals.

5. The method of claim 1, wherein the network is configured to utilize a Time-Division Multiplexing method for transmission on a digital side of the network so that serial data streams of several communication channels are combined using a multiplexing method.

6. The method of claim 1, wherein the first slave module is comprised of at least one of mechanical components and electrical components and the local clock generator of the first slave module is comprised of a flip-flop circuit or an oscillator.

7. The method of claim 1, wherein the local clock generator of the first slave module is a quartz oscillator, a voltage controlled crystal oscillator, or an oscillator circuit.

8. An apparatus for a communication system comprising:

a control computer connectable to a network;

the control computer configured to receive at least one first clock signal from a first module via the network, at least one second clock signal from a second module via the network during a first time window; and

at least one third clock signal from a third module via the network during a second time window, the second time window being different from the first time window such that the at least one third clock signal of the third module is not transmitted during the first time window; and

the control computer also configured to determine;

a first measurement for a deviation of a local clock generator of the second module relative to a local clock generator of the first module by comparing the at least one first clock signal transmitted by the first module to the at least one second clock signal transmitted by the second module and using the first measurement to control the local clock generator of the second module, and

a second measurement for a deviation of a local clock generator of the third module relative to the local clock generator of the first module by comparing the at least one first clock signal transmitted by the first module to the at least one third clock signal transmitted by the third module and using the second measurement to control the local clock generator of the third module.

9. The apparatus of claim 8, comprising:

a switch device connected between the control computer and the first module, the second module, and the third module, the switch device configured to receive the at least one first clock signal, at least one second clock signal and at least one third clock signal at different times and also configured to forward the at least one first clock signal, at least one second clock signal, and at least one third clock signal to the control computer at different times.

10. The apparatus of claim 9, wherein the control computer is a central control computer.

11. The apparatus of claim 8, comprising:

the first module, the second module, and the third module, the local clock generator of the first module comprised of a quartz oscillator, a voltage controlled crystal oscillator, or an oscillator circuit, the local clock generator of the second module comprised of a quartz oscillator, a voltage controlled crystal oscillator, or an oscillator circuit, and the local clock generator of the third module comprised of a quartz oscillator, a voltage controlled crystal oscillator, or an oscillator circuit.

12. The apparatus of claim 11, wherein the at least one first clock signal is transmitted as at least one clock signal data packet, the at least one second clock signal is transmitted as at least one clock signal data packet, and the at least one third clock signal is transmitted as at least one clock signal data packet.

13. The apparatus of claim 11, wherein the at least one first clock signal is sent via the network during a third time window, the third time window being different than the second time window and the third time window being different than the first time window such that the at least one first clock signal is not transmitted during the first time window and is not transmitted during the second time window.

14. The apparatus of claim 8, comprising:

the first module, the second module, and the third module, the local clock generator of the first module comprised of a flip-flop circuit or an oscillator and the first module comprised of at least one of mechanical components and electrical components, the local clock generator of the second module comprised of a flip-flop circuit or an oscillator and the second module comprised of at least one of mechanical components and electrical components, and the local clock generator of the third module comprised of a flip-flop circuit or an oscillator and the third module comprised of at least one of mechanical components and electrical components.

15. An apparatus comprising:

a first slave module having a local clock generator, the first slave module configured to determine a measurement for a deviation of the local clock generator of the first slave module relative to a clock generator of a master module, the measurement being determined from a comparison of a first clock signal received from the master module to a clock signal of the local clock generator of the first slave module,

the first slave module configured to use the determined measurement to control the local clock generator of the first slave module to synchronize the local clock generator of the first slave module to the clock generator of the master module;

the first slave module configured to send a second clock signal via a network in a first time window, the second clock signal being synchronous with a local clock of the local clock generator of the first slave module, the first time window being a time window that is different from time windows used for other clock signals of any other slave modules in the network to which the first slave module is connected; and

a second slave module having a local clock generator, the second slave module configured to determine a measurement for a deviation of the local clock generator of the second slave module relative to the clock generator of the master module, the measurement for the deviation of the local clock generator of the second slave module being determined from a comparison of the first clock signal received from the master module to a clock signal of the local clock generator of the second slave module, and

the second slave module configured to use the determined measurement for the deviation of the local clock generator of the second slave module relative to the clock generator of the master module to control the local clock generator of the second slave module to synchronize the local clock generator of the second slave module to the clock generator of the master module;

the second slave module configured to send a third clock signal via the network in a second time window, the third clock signal being synchronous with a local clock of the local clock generator of the second slave module, the second time window being a time window that is different from the first time window and being different from time windows used for other clock signals of any other slave modules in the network.

16. The apparatus of claim 15, comprising:

the master module, the master module configured to transmit the first clock signal to the first slave module.

17. The apparatus of claim 15, wherein the local clock generator of the first slave module is comprised of a quartz oscillator, a voltage controlled crystal oscillator, or an oscillator circuit.

18. The apparatus of claim 15, wherein the first slave module is comprised of at least one of mechanical components and electrical components and the local clock generator of the first slave module is comprised of a flip-flop circuit or an oscillator.