Spectracom VelaSync 1225, Руководство пользователя

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Figure 5-2:
IRIG E time code description
Additional information
The beginning of each 10 second time frame is identified by two consecutive 80 ms ele-
ments (P
0
and P
R
). The leading edge of the second 80 ms element (P
R
) is the "on time"
reference point for the succeeding time code. 1PPS position identifiers P
0
, P
1
… P
9
(80 ms duration) occur 0.1 s before 1PPS "on time" and refer to the leading edge of the
succeeding element.
The time code word and the control functions presented during the time frame are
pulse-width coded. The binary "zero" and index markers have a duration of 20 ms, and
the binary "one" has a duration of 50 ms. The leading edge is the 10 pps "on time" ref-
erence point for all elements.
The binary coded decimal (BCD) time-of-year code word consists of 26 digits beginning
at index count 6. The binary coded subword elements occur between position iden-
tifiers P
0
and P
5
(3 for seconds; 7 for minutes; 6 for hours; 10 for days) until the code
word is complete. An index marker occurs between the decimal digits in each subword
to provide separation for visual resolution. The least significant digit occurs first. The
BCD code recycles yearly.
Forty-five control functions occur between position identifiers P
5
and P
0
. Any control
function element for combination of control function elements can be programmed to
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APPENDIX