Format Encoding Modulation Carrier Coded Expressions Bit rate
Time Frame Inter
val
IRIG-G G001 DCLS N/A BCD
TOY
, CF 10000
pps
10 msec
IRIG-G G002 DCLS N/A BCD
TOY
10000
pps
10 msec
IRIG-G G005 DCLS N/A BCD
TOY
, BCD
YEAR
, and CF 10000
pps
10 msec
IRIG-G G006 DCLS N/A BCD
TOY
, BCD
YEAR
10000
pps
10 msec
IRIG-G G141 AM 100
kHz
BCD
TOY
, CF 10000
pps
10 msec
IRIG-G G142 AM 100
kHz
BCD
TOY
10000
pps
10 msec
IRIG-G G145 AM 100
kHz
BCD
TOY
, BCD
YEAR
, and CF 10000
pps
10 msec
IRIG-G G146 AM 100
kHz
BCD
TOY
, BCD
YEAR
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 ele
ment 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 bin
ary 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
SecureSync User Reference Guide 527
APPENDIX