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IRIG Carrier Frequencies

Each IRIG code specifies a carrier frequency that is modulated to encode date and time, as well as control bits to time-stamp events. Initially, IRIG applications were primarily military and government associated. Today, IRIG is commonly used to synchronize voice loggers, recall recorders, and sequential event loggers found in emergency dispatch centers and power utilities.

Available IRIG output signals

Format Encoding Modulation Carrier Coded Expressions Bit rate Time Frame Interval
IRIG-A
IRIG-A A000 DCLS N/A BCDTOY, CF and SBS 1000 pps 0.1 sec
IRIG-A A001 DCLS N/A BCDTOY, CF 1000 pps 0.1 sec
IRIG-A A002 DCLS N/A BCDTOY 1000 pps 0.1 sec
IRIG-A A003 DCLS N/A BCDTOY, SBS 1000 pps 0.1 sec
IRIG-A A004 DCLS N/A BCDTOY, BCDYEAR, CF and SBS 1000 pps 0.1 sec
IRIG-A A005 DCLS N/A BCDTOY, BCDYEAR, and CF 1000 pps 0.1 sec
IRIG-A A006 DCLS N/A BCDTOY, BCDYEAR 1000 pps 0.1 sec
IRIG-A A007 DCLS N/A BCDTOY, BCDYEAR, and SBS 1000 pps 0.1 sec
IRIG-A A130 AM 10 kHz BCDTOY, CF and SBS 1000 pps 0.1 sec
IRIG-A A131 AM 10 kHz BCDTOY, CF 1000 pps 0.1 sec
IRIG-A A132 AM 10 kHz BCDTOY 1000 pps 0.1 sec
IRIG-A A133 AM 10 kHz BCDTOY, SBS 1000 pps 0.1 sec
IRIG-A A134 AM 10 kHz BCDTOY, BCDYEAR, CF and SBS 1000 pps 0.1 sec
IRIG-A A135 AM 10 kHz BCDTOY, BCDYEAR, and CF 1000 pps 0.1 sec
IRIG-A A136 AM 10 kHz BCDTOY, BCDYEAR 1000 pps 0.1 sec
IRIG-A A137 AM 10 kHz BCDTOY, BCDYEAR, and SBS 1000 pps 0.1 sec
IRIG-B
IRIG-B B000 DCLS N/A BCDTOY, CF and SBS 100 pps 1 sec
IRIG-B B001 DCLS N/A BCDTOY, CF 100 pps 1 sec
IRIG-B B002 DCLS N/A BCDTOY 100 pps 1 sec
IRIG-B B003 DCLS N/A BCDTOY, SBS 100 pps 1 sec
IRIG-B B004 DCLS N/A BCDTOY, BCDYEAR, CF and SBS 100 pps 1 sec
IRIG-B B005 DCLS N/A BCDTOY, BCDYEAR, and CF 100 pps 1 sec
IRIG-B B006 DCLS N/A BCDTOY, BCDYEAR 100 pps 1 sec
IRIG-B B007 DCLS N/A BCDTOY, BCDYEAR, and SBS 100 pps 1 sec
IRIG-B B120 AM 1 kHz BCDTOY, CF and SBS 100 pps 1 sec
IRIG-B B121 AM 1 kHz BCDTOY, CF 100 pps 1 sec
IRIG-B B122 AM 1 kHz BCDTOY 100 pps 1 sec
IRIG-B B123 AM 1 kHz BCDTOY, SBS 100 pps 1 sec
IRIG-B B124 AM 1 kHz BCDTOY, BCDYEAR, CF and SBS 100 pps 1 sec
IRIG-B B125 AM 1 kHz BCDTOY, BCDYEAR, and CF 100 pps 1 sec
IRIG-B B126 AM 1 kHz BCDTOY, BCDYEAR 100 pps 1 sec
IRIG-B B127 AM 1 kHz BCDTOY, BCDYEAR, and SBS 100 pps 1 sec
IRIG-E
IRIG-E E000 DCLS N/A BCDTOY, CF and SBS 10 pps 1 sec
IRIG-E E001 DCLS N/A BCDTOY, CF 10 pps 1 sec
IRIG-E E002 DCLS N/A BCDTOY 10 pps 1 sec
IRIG-E E003 DCLS N/A BCDTOY, SBS 10 pps 1 sec
IRIG-E E004 DCLS N/A BCDTOY, BCDYEAR, CF and SBS 10 pps 1 sec
IRIG-E E005 DCLS N/A BCDTOY, BCDYEAR, and CF 10 pps 1 sec
IRIG-E E006 DCLS N/A BCDTOY, BCDYEAR 10 pps 1 sec
IRIG-E E007 DCLS N/A BCDTOY, BCDYEAR, and SBS 10 pps 1 sec
IRIG-E E110 AM 100 Hz BCDTOY, CF and SBS 10 pps 1 sec
IRIG-E E111 AM 100 Hz BCDTOY, CF 10 pps 1 sec
IRIG-E E112 AM 100 Hz BCDTOY 10 pps 1 sec
IRIG-E E113 AM 100 Hz BCDTOY, SBS 10 pps 1 sec
IRIG-E E114 AM 100 Hz BCDTOY, BCDYEAR, CF and SBS 10 pps 1 sec
IRIG-E E115 AM 100 Hz BCDTOY, BCDYEAR, and CF 10 pps 1 sec
IRIG-E E116 AM 100 Hz BCDTOY, BCDYEAR 10 pps 1 sec
IRIG-E E117 AM 100 Hz BCDTOY, BCDYEAR, and SBS 10 pps 1 sec
IRIG-E E120 AM 100 Hz BCDTOY, CF and SBS 10 pps 1 sec
IRIG-E E121 AM 1kHz BCDTOY, CF 10 pps 10 sec
IRIG-E E122 AM 1kHz BCDTOY 10 pps 10 sec
IRIG-E E123 AM 1kHz BCDTOY, SBS 10 pps 10 sec
IRIG-E E124 AM 1kHz BCDTOY, BCDYEAR, CF and SBS 10 pps 10 sec
IRIG-E E125 AM 1kHz BCDTOY, BCDYEAR, and CF 10 pps 10 sec
IRIG-E E126 AM 1kHz BCDTOY, BCDYEAR 10 pps 10 sec
IRIG-E E127 AM 1kHz BCDTOY, BCDYEAR, and SBS 10 pps 10 sec
IRIG-G
IRIG-G G001 DCLS N/A BCDTOY, CF 10000 pps 10 msec
IRIG-G G002 DCLS N/A BCDTOY 10000 pps 10 msec
IRIG-G G005 DCLS N/A BCDTOY, BCDYEAR, and CF 10000 pps 10 msec
IRIG-G G006 DCLS N/A BCDTOY, BCDYEAR 10000 pps 10 msec
IRIG-G G141 AM 100 kHz BCDTOY, CF 10000 pps 10 msec
IRIG-G G142 AM 100 kHz BCDTOY 10000 pps 10 msec
IRIG-G G145 AM 100 kHz BCDTOY, BCDYEAR, and CF 10000 pps 10 msec
IRIG-G G146 AM 100 kHz BCDTOY, BCDYEAR 10000 pps 10 msec
NASA-36 N/A AM 1msec UNKNOWN 100 pps 1 sec
NASA-36 N/A DCLS 10 msec UNKNOWN 100 pps 1 sec

The Spectracom IRIG formats use the control functions for BCD year information and a Time Sync Status bit and in format E the control functions are used for straight binary seconds (SBS). Refer to individual IRIG Time Code description figures and text. IRIG Standard 200-98 format B had 27 control bits and format E had 45 bits for control functions. These control bits could be used for any use and there was no defined function. Spectracom used the control function element at index count 55 as the TIME SYNC STATUS and the sub-frame after position identifiers P6 and P7 as the year info and for format E the sub-frame after P8 and P9 for the straight binary seconds (SBS). The position of the BCD year information does not conform to the newer IRIG Standard 200-04. IRIG Standard 200-04 incorporated the year information after P5 and reduced the allocated control bits to 18 for format B and 36 for format E.

Note: DCLS is DC Level Shifted output, pulse width modulated with a position identifier having a positive pulse width equal to 0.8 of the reciprocal of the bit rate, a binary one (1) having a positive pulse width equal to 0.5 of the reciprocal of the bit rate and a binary zero (0) having a positive pulse width equal to 0.2 of the reciprocal of the bite rate.

SecureSync can provide IRIG A, IRIG B, IRIG E and IRIG G code in amplitude modulated (AM) or pulse width coded (TTL) formats. A signature control feature may be enabled for any IRIG output. Signature control removes the modulation code when a Time Sync Alarm is asserted.