Format Encoding Modulation Carrier
Coded Expres-
sions
Bit rate
Time
Frame
Interval
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
IRIG-H
IRIG-H H002 DCLS N/A BCD
TOY
1 pps 1 sec
IRIG-H H122 AM 1KHz BCD
TOY
1 pps 1 sec
NASA-36
NASA-
36
N/A AM 1msec UNKNOWN 100 pps 1 sec
NASA-
36
N/A DCLS 10msec 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 fig-
ures 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 iden-
tifiers 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.
592 SecureSync 2400 User Manual
APPENDIX
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