IRIG timecode: Difference between revisions

Revision as of 10:27, 23 January 2009

Revision as of 09:10, 29 June 2009

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'''Inter-range instrumentation group time codes''', commonly known as "IRIG" timecodes, were created by the TeleCommunications Working Group of the [[IRIG|Inter-Range Instrumentation Group]], the standards body of the [[Range Commanders Council]]. Work on these standards started in October [[1956]], and the original standards were accepted in [[1960]].

The original formats were described in IRIG Document 104-60, later revised and reissued in August [[1970]] as IRIG Document 104-70, upgraded later that year as the IRIG Document to the status of a Standard, IRIG Standard 200-70. The latest version of the Standard is IRIG Standard 200-04.

The different timecodes defined in the Standard have alphabetic designations. A, B, D, E, G, and H are the standards currently defined by 200-9804. C was in the original specification, but was replaced by H. The main difference between codes is their rate, which varies between one pulse per minute and 10,000 pulses per second.

* A: 1000 PPS

* B: 100 PPS

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:7) BCD, BCD_Year, SBS

The recognized combinationssignal identification numbers for each format according to the standard are200-04 consist of:

{| class="wikitable" border="1"

* A: A000, A003, A130, A132, A133

|+ Permissible Code Formats

* B: B000, B003, B120, B122, B123, B150, B152, B153

! Format

* D: D001, D002, D111, D112, D121, D122

! Modulation Frequency

* E: E001, E002, E111, E112, E121, E122

! Frequency / Resolution

* G: G001, G002, G141, G142

! Coded Expressions

* H: H001, H002, H111, H112, H121, H122

|-

! A

| 0,1,2

| 0,3,4,5

| 0,1,2,3,4,5,6,7

|-

! B

| 0,1,2

| 0,2,3,4,5

| 0,1,2,3,4,5,6,7

|-

! D

| 0,1

| 0,1,2

| 1,2

|-

! E

| 0,1

| 0,1,2

| 1,2,5,6

|-

! G

| 0,1,2

| 0,4,5

| 1,2,5,6

|-

! H

| 0,1

| 0,1,2

| 1,2

|}

Thus the complete signal identification number consists of one letter and three digits. E.g. the signal designated as B122 is deciphered as follows: Format B, Sine wave (amplitude modulated),

1 kHz carrier/1 ms resolution, and Coded expressions BCDTOY.

The most commonly used of the standards is IRIG B, then IRIG A, then probably IRIG G. Time code formats directly derived from IRIG H are used by [[National Institute of Standards and Technology|NIST]] [[radio station]]s [[WWV (radio station)|WWV]], [[WWVH]] and [[WWVB]].