TrueTime IRIG NTS-100, Руководство пользователя

Страница: 74 / 75

1/20/97
N N T T S S - - 2 2 0 0 1 1 . . M M A A N N C C - - 2 2 R R e e v v A A
C-3 EMBEDDED WORST-CASE TIME ERROR FLAGS
C-3.1 Five flags are encoded in the control function segment of the IRIG B code. The first flag
encoded at element P5+40ms is the LOCK indicator. It is a binary 1 when the unit has
lost contact with satellite signals. The second flag encoded at element P5+60ms is a
binary 1 when the worst-case time error exceeds threshold 1 as described in SECTION
III, "SERIAL I/O FUNCTION 05 -TIME QUALITY ENABLE/SETUP". Element P5+70ms
is a binary 1 when the worst-case time error exceeds threshold 2. Element P5+80ms
encodes a binary 1 when the error exceeds threshold 3 and P5+90ms when the error
exceeds threshold 4.
Figure C-1 (IRIG-B)
10 20 30 40 50 60 70 80 90 0
0
P5 PR
RE
IRIG-B TIME CODE FORMAT
TIME FRAME 1 SECOND
TIME
Time in 0.01 s
TYPICAL MODULATED CARRIER (1000Hz)
HOUR
BCD Time-of-Year
P0 PR P P2
0.01 s Index Marker,
Duration 2 ms
0.1 s Position Identifier
Duration 8 ms
REF
SECOND
On-Time
MINUTE
P3 P4
DAY
Control Functions
P6 P7
Lock Indicator
P8 P9 P0
1 2 4 8 10 20 40 1 2 4 8 10 20 40 1 2 4 8 10 20 40 10 20 40 80 1 2 4 8
Binary One
5 ms Typical
Time Quality 4
Time Quality 1
Time Quality 2
Time Quality 3
10 ms Typical
100 200
3X
X