Spectracom VelaSync 1225, User Manual

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Standard 200-98 format B had 27 control bits and format E had 45 bits for control func-
tions. 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 identifiers 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 pos-
ition 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) hav-
ing a positive pulse width equal to 0.2 of the reciprocal of the bite
rate.
VelaSync can provide IRIG A, IRIG B, IRIG E and IRIG G code in amplitude modulated
(AM) or pulse width coded (TTL) formats. A signature control feature may be enabled
for any IRIG output. Signature control removes the modulation code when a Time Sync
Alarm is asserted.
5.3.3 IRIG B Output
The IRIG B Time Code description follows.
226 VelaSync User's Manual
APPENDIX