Spectracom VersaSync User Manual page 293

Time frame : 10 seconds.
Code Digit Weighting :
Binary Coded Decimal time of year.
Code world - 26 binary digits.
Tens of seconds, minutes, hours, and days.
Recycles yearly.
Code Word Structure : BCD word tens of seconds digits begin at index count 6. Binary
coded elements occur between position identifier elements P0 and P5 (3 for seconds, 7
for minutes, 6 for hours, and 10 for days) until the code word is complete. An index
marker occurs between decimal digits in each group to provide separation for visual res-
olution. Least significant digit occurs first.
Control Functions : IRIG formats reserve a set of elements known as Control Functions (CF)
for the encoding of various control, identification, or other special purpose functions.
IRIG E has 45 Control Functions located between elements 50 and 98. The VersaSync
uses the Control Function field to encode year data, time synchronization status, and
SBS time data. Table B-2 lists the Control Function Field and each element's function.
Element 55 is the time synchronization status bit. Element 55 is a Binary 1 when the front panel
time synchronization lamp is green, and a Binary 0 when the lamp is red.
Year information consists of the last two digits of the current year (i.e. 98, 99, etc.). Elements 60
through 63 contain the binary equivalent of year units. Elements 65 through 68 contain the bin-
ary equivalent of tens of years. In keeping with IRIG formats, the least significant bit occurs first.
Elements 80 through 97 are encoded with the Straight Binary Seconds (SBS) time data. The
SBS time data is incremented in 10-second steps and recycles every 24 hours.
Pulse rates:
Element rate: 10 per second.
Position identifier rate: 1 per second.
Reference marker rate: 1 per 10 seconds.
Element identification: The "on time" reference point for all elements is the pulse leading
edge.
Index marker (Binary 0 or uncoded element): 20 millisecond duration.
Code digit (Binary 1): 50 millisecond duration.
Position identifier: 80 millisecond duration.
VersaSync User Manual
APPENDIX
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