IRIG Time Code Formats

Contents:


MEINBERG IRIG Receivers and IRIG Generators

Satellite Receiver with integrated time code generator (DIN Mounting Rail) IRIG Time Code Receiver IRIG Time Code Receiver for Computers (PCI Express) IRIG Time Code Receiver and Generator for Computers (PCI Express) NTP Server in 1U Case for Server Rackmount


Overview


The term IRIG signals is frequently used to refer to a whole group of serial timecodes, which use a continuous stream of binary data to transmit information on date and time. The individual time code formats can be distinguished by the signal characteristics, e.g. modulated versus unmodulated, which require different ways of signal transmission, by the data rate, and by the kind of information included in the transmitted data.

Over the years different organizations have published several standards defining the basic timecodes and also extensions to those time codes to meet the requirements of new applications.

Back in 1956 the TeleCommunication Working Group (TCWG) of the American Inter Range Instrumentation Group (IRIG) was mandated to standardize different time code formats, resulting in IRIG Document 104-60 which was published in 1960. In 1970 the document was revised to IRIG Document 104-70, and later published as IRIG Standard 200-70. In 1995 there was another revision which became IRIG Standard 200-95. The latest revisions are IRIG Standard 200-98 from 1998 which defined a group of Manchester modulated signals, and IRIG Standard 200-04 which is the current version specifying some new codes which also transmit a year number.

A copy of the latest version can be obtained by writing to:

Secretariat, Range Commanders Council
White Sands Missile Range
New Mexico, 88002-5110

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Description of IRIG Formats

The name of an IRIG code format consists of a single letter plus 3 subsequent digits. Each letter or digit reflects an attribute of the corresponding IRIG code. The following table contains standard code formats defined in IRIG standard 200-98:

 IRIG A   IRIG B   IRIG D   IRIG E   IRIG G   IRIG H 
A000 B000 D001 E001 G001 H001
A003 B003 D002 E002 G002 H002
A130 B120 D111 E111 G006 H111
A132 B122 D112 E112 G141 H112
A133 B123 D121 E121 G142 H121
    D122 E122 G146 H122

The code format names are composed as described below:

First letter:
Rate Designation
A
B
D
E
G
H
1000 PPS
100 PPS
1 PPM
10 PPS
10000 PPS
1 PPS
1st Digit:
Form Designation
0
1
DC Level Shift (DCLS), width coded, no carrier
Sine wave carrier, amplitude modulated
2nd Digit:
Carrier Resolution
0
1
2
3
4
No carrier(DCLS)
100 Hz / 10 millisecond resolution
1 kHz / 1 millisecond resolution
10 kHz / 100 microsecond resolution
100 kHz / 10 microsecond resolution
3rd Digit:
Coded Expressions
0
1
2
3
6
BCD, CF, SBS
BCD, CF
BCD
BCD, SBS
BCD, BCD_Year

Abbreviations used in the table above:

  • BCD - Binary Coded Decimal, coding of time (HH,MM,SS,DDD)
  • SBS - Straight Binary Second of day (0....86400)
  • CF - Control Functions depending on the user application


This drawing shows the dataframes from IRIG-B Code (IRIG - B000/B120 to IRIG - B007/B127)

IRIG-B Data frames

Handbuch   You can download this overview as an PDF here.



This drawing shows the dataframes of IEEE1344 / C37.118 code

IEEE1344 / C37.118 Data frames

Handbuch   You can download this IEEE1344 overview as an PDF here.



The graphic below shows the general structure of IRIG codes:

IRIG Timecodes

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Modulated IRIG Codes


Modulated IRIG codes consist of a carrier frequency which is modulated with the time code. The carrier frequency is determined by name of the time code format as mentioned in the table above.

Example: B123

  • The second digit indicates carrier frequency (2 -> 1kHz)
  • The carrier envelope corresponds to the unmodulated code
  • The mark-to-space ratio is typically 10:3 (can be in a range of 10:3 up to 10:6)

An also commonly used format is AFNOR NF S87-500, a French standard, not an IRIG code, but very similar

IRIG Timecodes AM

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Techniques for transmission of modulated codes:

  • coaxial cable terminated in 50Ω or high-Z, 600Ω e.g. (a standard method)
  • symmetrical twisted pair
  • analog fiber optic transmitter/receiver (rare)

The signal level for IRIG code has not been defined in IRIG 200-98.


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Unmodulated IRIG Codes


  • standardized in IRIG 200-98
  • DC Level Shift Codes without carrier

Techniques for transmission of unmodulated codes

  • TTL Level over coaxial cable (should be terminated correctly)
  • RS422 differential Level, twisted pair lines
  • RS232 Level, shielded cable (only short distances)
  • Fiber Optic

Transmission of unmodulated IRIG Codes

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Meinberg IRIG Receivers


IRIG Time Code Receiver (Eurocard)

  • Two independently configurable serial ports
  • Pulse per second (PPS) output at TTL Level
  • Pulse per minute (PPM) output at TTL Level
  • Emulation of DCF77 time code

PCI Time Code Receiver

  • PCI card, 3.3 V/5 V PCI, 33/66 MHz, PCI-X compatible
  • One serial port
  • Can generate interrupts

PCI Express Time Code Receiver

  • PCI Express card, 1x Lane, Low Profile form factor
  • One serial port
  • Can generate interrupts

PCI Time Code Receiver and Generator

  • PCI card, 3.3 V/5 V PCI, 33/66 MHz, PCI-X compatible
  • One serial port
  • Integrated Solution including a Time Code Reader and a Generator
  • Can generate interrupts
  • Optional optical inputs/outputs available

PCI Express Time Code Receiver and Generator

  • Single lane (x1) PCI Express (PCIe) Interface
  • Two serial ports
  • Integrated Solution including a Time Code Reader and a Generator
  • Can generate interrupts
  • Programmable Pulse Outputs
  • DDS frequency synthesizer
  • Optional optical inputs/outputs available

Network Time Server LANTIME M300

  • IRIG disciplined NTP Time Server


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Meinberg IRIG Generators and combined Readers/Generators


IRIG TimeCode Generator

  • Can be synchronized by GPS16x or PZF509
  • Can be equipped with oscillator for special purposes
  • Configurable serial port
  • Selectable timestring for synchronization (Meinberg Standard / Uni Erlangen)
  • ALC (Automatic Level Control) for AFNOR NF S87-500 compatibility
  • PPS regeneration for special purposes
  • Bootstrap loader/flash Memory allows SW update via serial port

PCI Time Code Receiver and Generator

  • PCI card, 3.3 V/5 V PCI, 33/66 MHz, PCI-X compatible
  • One serial port
  • Integrated Solution including a Time Code Reader and a Generator
  • Can generate interrupts
  • Optional optical inputs/outputs available

PCI GPS Receiver and IRIG Time Code Generator

  • PCI card, 3.3 V/5 V PCI, 33/66 MHz, PCI-X compatible
  • One serial port
  • Integrated Solution including a GPS receiver and a Time Code Generator
  • Can generate interrupts

GPS receiver with LC Display

  • GPS receiver with IRIG time code generator
  • Up to 4 RS232 interfaces
  • Standard frequency outputs
  • Pulses per second and per minute
  • 2 time trigger inputs
  • DDS frequency synthesizer
  • DCF77 simulation
  • Antenna connected with up to 300 m of standard coaxial cable RG58

The GPS receiver can be ordered with the Time Code option or - in a modular system - is capable of providing time synchronization for a Time Code Generator (TCG - see above).



IRIG Time Code IRIG-A IRIG-B