Model 5601MSC
Model 5601MSC Master SPG/Master Clock System
OPERATION
Revision 2.2
Page - 43
2.3.3.8. No Time Reference
When the time reference source is set to
None
, the 5601MSC will ignore all time reference sources and
the
system clock
will freerun. The time and date must be set manually using the
Set System Time
and
Set System Date
menu items located in the
GENERAL
root menu. It is recommended to set the system
clock time to UTC rather than to local time. Local time can then be specified using a time zone offset
from UTC on the timecode outputs. The IRIG-B124 and IRIG-B127 formats also include the current
year as a two-digit number (e.g. 2011 = 11).
The “eyeball and wristwatch” method of setting the
system clock
cannot be considered accurate time.
The NTP server will report an unlocked condition (LI_Alarm) unless spoofing is enabled. See section
2.4 for more information.
2.3.4. LTC and VITC Timecode
The primary purpose of LTC and VITC timecode is to count frames. Each LTC count relates to one
frame of video. The Linear Time Code output waveforms are aligned to video so that the end of the
sync word lines up with the start of the field1 vertical sync. This occurs on line 4 for the NTSC standard,
and line 1 for the PAL standard. Vertical Interval Time Code can be inserted onto any black burst sync
output and is inserted onto a vertical blanking line once per field, twice per frame. See Figure 2-15 for
LTC and VITC timing relationships. Note that VITC is inserted once per field allowing VITC timecode to
count fields. LTC timecode has one count per frame and does not count fields.
Figure 2-15: Detail of 29.97Hz LTC Waveform Alignment to NTSC Video
The LTC/VITC timecode rates supported by the 5601MSC are summarized in Table 2-7. All of these
rates maintain alignment to their respective video standards. When VITC is inserted onto a PAL black
burst sync output, it runs at 25Hz. When VITC is inserted onto an NTSC black burst sync output it runs
at 29.97Hz. In addition to video alignment, the LTC and VITC timecode for the 25Hz and 29.97Hz rates
can be adjusted to maintain color frame alignment as per SMPTE ST 12-1. Refer to section 2.3.4.2 for
more information on how color frame alignment is performed.
End of LTC Sync Word
NTSC Line 4
VITC Line 14
0
1
Field 1
Содержание 5601MSC
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