evertz 5700MSC-IP - LTC and VITC Timecode; Figure 3-15: Detail of 29.97 Hz LTC Waveform Alignment to NTSC Video

5700MSC-IP
IP Network Grand Master Clock & Video Master Clock System
Revision 0.2 Page - 45
to eight external NTP servers can be defined. All enabled NTP servers will be contacted and the
server response with the best stratum and dispersion values will be chosen to jam the system clock.
3.3.3.6. No Time Reference
When the time reference source is set to None, the 5700MSC-IP 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 “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.
3.3.4. 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 3-15 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 3-15: Detail of 29.97Hz LTC Waveform Alignment to NTSC Video
The LTC/VITC timecode rates supported by the 5700MSC-IP are summarized in Table 3-7. 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.
End of LTC Sync Word
NTSC Line 4
VITC Line 14
0
1
Field 1