App Notes

What does IRIG stand for?

Inter Range Instrumentation Group
What is IRIG Standard?
Modern day electronic systems such as communication systems, data handling systems, and missile and spacecraft tracking systems require time-of-day and year information for correlation of data with time. Serial formatted time codes are used to efficiently interface the timing system output with the user system.  Standardization of time codes is necessary to ensure system compatibility among the various ranges, ground tracking networks, spacecraft and missile projects, data reduction facilities, and international cooperative projects.   These digital codes are typically amplitude modulated on an audio sine wave carrier or transmitted as fast rise-time TTL signals.

The use of the IRIG standard is to provide a standard protocol for serial time codes that are generated for correlation of data with time.

What is the latest IRIG specification?
IRIG Standard 200-04 (added year information to format).   Previous revisions are IRIG Standard 200-98 (added Manchester modulation) and  IRIG Standard 200-95.   IRIG Document 104-60 was the original standard accepted in 1960.

What is IRIG-B?
IRIG-B refers to a serial time code format.   This a timing signal that has a rate of 100 pulse per second signal,  There are other rate that are designated in accordance with the IRIG Standard 200-04  (see below).  IRIG-B sends Day of Year, Hour, Minute and Second data on a 1KHz carrier, with an update rate of one second.  IRIG-B DCLS  (DC level shift) is IRIG-B without the 1KHz Carrier.

What are the IRIG Formats?

 Format  Rate  Count Interval
IRIG-A  1,000 PPS (pulse per second)  1 ms
IRIG-B  100 PPS  10 ms
IRIG-D  1 PPM (pulse per minute)  1 minute
IRIG-E  10 PPS  0.1 second
IRIG-G  10,000 PPS  0.1 ms
IRIG-H  1 PPS  1 second

Note IRIG-C was replaced by IRIG-H

More detail on IRIG Designations (e.g. IRIG-B120)

How to Interfacing with high voltage IRIG signals

IRIG Distribution Products

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