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IRIG-Hardware from Meinberg
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In 1956 the TeleCommunication Working Group (TCWG) of the American Inter Range Instrumentation
Group (IRIG) was mandated to standardize the different time code formats.
IRIG document 104-60 had defined the original IRIG formats, was revised in 1970 to IRIG Document 104-70,
and published later as IRIG Standard 200-70. The latest publication is 200-98.
A copy of the latest version can be obtained by writing to:
Secretariat, Range Commander's Council
White Sands Missile Range
New Mexico, 88002
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Description of IRIG Formats
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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 |
G141 |
H111 |
| A132 |
B122 |
D112 |
E112 |
G142 |
H112 |
| A133 |
B123 |
D121 |
E121 |
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H121 |
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D122 |
E122 |
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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
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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 |
BCD, CF, SBS
BCD, CF
BCD
BCD, SBS |
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
The graphic below shows the general structure of IRIG codes:
 Click for higher resolution
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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 NFS-87-500, a French standard,
not an IRIG code, but very similar
Click for higher resolution
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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- 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
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Meinberg IRIG Generators and combined Readers/Generators
- 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-NFS 87-500 compatibility
- PPS regeneration for special purposes
- Bootstrap loader/flash Memory allows SW update via serial port
- 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 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
- New: GPS receiver GPS167 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 250 m of standard coaxial cable RG58
The GPS167 can be ordered with the ZTC option or - in a modular system - is capable of
providing time synchronization for a TCG511 module (see above).
Supported IRIG Code Formats:
- TCG511 provides modulated IRIG codes at 3 Vpp (MARK) into 50Ω
- AFNOR code is available at 2.17 Vpp (MARK) into 600Ω
- Unmodulated codes are available at TTL, RS232, RS422 level and an open drain output
- AFNOR-NFS 87-500 (DC) is not standardized!
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