Spectracom VersaSync - Page 294

Reference marker: 80 millisecond duration, 1 per 10 seconds. The reference marker
appears as two consecutive position identifiers. The second position identifier or ref-
erence marker is the on-time point for the succeeding code word.
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 elements
(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" reference point for all ele-
ments.
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 identifiers 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 read a binary
282 VersaSync User Manual
APPENDIX