# US 8,417,981 B2 · Time format conversion method, device and system

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- Number: US 8,417,981 B2
- Document ID: US8417981B2
- Status: Granted
- Kind: B2
- Application number: 12/694,537
- Filed: 2010-01-27
- Published: 2011-07-28
- Granted: 2013-04-09
- Earliest claimed: 2010-01-26
- Assignees: Ruggedcom Inc.
- Applicants: Yuri Luskind; Petru Ovidiu Lupas; Roger Moore
- Inventors: Yuri Luskind; Petru Ovidiu Lupas; Roger Moore
- Web page: https://patentgrep.com/patent/US8417981B2

## CPC

- G06F 1/12: Synchronisation of different clock signals {provided by a plurality of clock generators}
- G04R 20/06: Decoding time data; Circuits therefor
- H04J 3/0688: {Change of the master or reference, e.g. take-over or failure of the master}
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G04R: RADIO-CONTROLLED TIME-PIECES
- H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S)

## Abstract

A method and device for converting between different time domains at a local unit utilizing an processor is disclosed. Time counters to count time in at least two different formats are located locally at each unit. Once a time conversion is initiated, a time stamp is received by the processor and the time counter in the new time domain commences calculating an adjustment count. Once the converted time is received from the processor, the received time plus the adjustment count are summed to provide a time base for the new time domain. The time counters continue counting in their respective time domains after conversion.

## Claims

### Claim 1

A method for converting from a first time format to a second time format at a local unit connected to a network utilizing a processor in the local unit, said second time format different from the first format, said method comprising:
utilizing a first counter at the local unit to count time in the first time format;
receiving at a processor interface a latch time request signal from the processor;
in response to the latch time request signal, sending a set time signal representing current time in the first time format to the processor representing time of receipt of the latch time request signal in the first time format, and, substantially simultaneously commencing an adjustment time counter in a second counter at the local unit to count adjustment time in the second time format;
receiving a set time converted signal from the processor representing the current time converted into the second time format;
in response to receiving the set time converted signal, summing the set time converted in the second time format as represented by the set time converted signal received from the processor to the adjustment time counted in the adjustment time counter in the second counter; and
initializing a time base in the second counter in the second time format based on the sum of the set time converted in the second time format and the adjustment time counted in the adjustment counter in the second counter in the second time format.

### Claim 2 (depends on 1)

The method as defined in claim 1 further comprising:
after conversion to the second time format, utilizing the first counter to count time in the first time format; and
utilizing the second counter to count time in the second format.

### Claim 3 (depends on 1)

The method as defined in claim 1 wherein the processor is a multitasking processor executing undetermined other tasks when the set time signal is received.

### Claim 4 (depends on 1)

The method as defined in claim 1 wherein only one of the first time format or the second time format is a Universal Time (UTC) based time format.

### Claim 5 (depends on 4)

The method as defined in claim 4 wherein one of the first time format or the second time format is based on IEEE 1588 Standard.

### Claim 6 (depends on 5)

The method as defined in claim 5 wherein at least one of the first time format or the second time format is UTC based time format selected from the group consisting of Global Positioning Satellite (GPS) and Inter Range instrumentation Group (IRIG).

### Claim 7 (depends on 1)

The method as defined in claim 1 wherein the local unit is selected from the group consisting of Field Programmable Gate Arrays, Switches and Routers.

### Claim 8 (depends on 1)

The method as defined in claim 1 wherein the time conversion occurs at initialization or network interruptions.

### Claim 9 (depends on 1)

The method as defined in claim 1 wherein the local unit is a Line Module, the first time format is IEEE 1588 Standard and the second time format is Inter Range Instrumentation Group (IRIG-B).

### Claim 10 (depends on 2)

The method as defined in claim 2, wherein the time references outputted by the first time counter and the second time counter are synchronized within 10ns.

### Claim 11

A device for facilitating conversion between a first time format and a second time format different from the first time format, utilizing a processor, said device comprising:
a processor interface for sending and receiving signals to and from the processor;
a first counter for counting time in the first time format;
a second counter for counting time in the second time format;
a time update controller connected to the first time counter, the second time counter and the processor interface;
wherein, when the processor interface receives a latch time request signal from the processor, the update controller sends a set time signal representing current time in the first time format to the processor and commences an adjustment counter in the second counter in the second time format; and
wherein, when the processor interface receives a set time converted signal representing the current time converted to the second time format from the processor, the second counter sums the set time converted to the second time format as represented by the set time converted signal with the contents of the adjustment counter in the second counter to initialize a time base in the second time format.

### Claim 12 (depends on 11)

The device as defined in claim 11 wherein after the conversion from the first time format to the second time format, the first counter counts time in the first time format and the second counter counts time in the second time format.

### Claim 13 (depends on 11)

The device as defined in claim 11 wherein the time update controller initially sends a request time conversion to the processor to initiate the time conversion; and
wherein the latch time request signal is sent from the processor in response to the request time conversion signal.

### Claim 14 (depends on 11)

The device as defined in claim 11 wherein one of the first time format or the second time format is based on IEEE 1588 Standard.

### Claim 15 (depends on 11)

The device as defined in claim 11 wherein the time update controller sends the request time conversion signal at initialization of the network or after a network interruption.

### Claim 16 (depends on 14)

The device as defined in claim 14 wherein at least one of the first time format or the second time format is UTC based time format selected from the group consisting of Global Positioning Satellite (GPS) and Inter Range Instramentation Group (IRIG-B).

### Claim 17 (depends on 11)

The device as defined in claim 11 wherein the local unit is selected from the group consisting of Field Programmable Gate Arrays, Switches, Routers, line modules and control modules.

### Claim 18

In a network having a plurality of nodes, each node connected to the network and communicating with at least one other remotely located node connected to the network, a system for converting between different time formats at the local unit, said system comprising:
in a first node:
a first counter for counting time in a first time format;
a second counter for counting time in a second time format;
a processor for converting time in the first time format to the second time format:
a processor interface for sending and receiving signals to and from the processor; and
a time update controller connected to the first time counter, the second time counter and the external processor interface;
wherein when the processor interface receives a latch time request signal from the processor, the update controller sends a set time signal representing the current time in the first time format to the processor and commences an adjustment counter in the second counter in the second time format;
wherein when the processor receives the set time signal, the processor converts the current time as represented by the set time signal from the first time format to the second time format and sends a set time converted signal representing the current time converted to the second time format; and
wherein when the processor interface receives the set time converted signal from the processor, the second counter sums the set time converted to the second time format as represented by the set time converted signal, with the contents of the local adjustment counter to initialize a time base in the second time format.

### Claim 19 (depends on 18)

The system as defined in claim 18 further comprising:
in one of the nodes of the network:
a GPS antenna for obtaining UTC time and sending UTC network time reference signals to at least one other node in the network representing the UTC time reference obtained from the GPS antenna; and
in the first node:
wherein the first time format is UTC time format obtained from the GPS antenna and the UTC network time reference signals; and
wherein the set time signal representing the current time in the first time format corresponds to the time represented by the UTC network time reference signal.

### Claim 20 (depends on 19)

The system as defined in claim 19 wherein the UTC time format is converted to IEEE time format and stored in the second time counter; and
wherein after the IEEE time in the second time format has been stored in the second counter, the second time format is converted to the first time format using the processor and the first counter is initialized with the UTC time converted from the second time format.

### Claim 21 (depends on 19)

The system as defined in claim 19 further comprising:
in a second node different from the first node:
a standby GPS antenna for obtaining UTC time and sending the UTC network time reference signals to at least one other node in the network representing the UTC time reference obtained by the GPS standby antenna; and
wherein the GPS standby antenna is operational only if the GPS antenna is not operational.