Level adjustments, Timing/blanking adjustments, Using – Grass Valley 8950ADC User Manual
Page 14: External sync, For timing considerations)
14
8950ADC Instruction Manual
Configuration
Level Adjustments
The factory (default) settings for signal processing functions are set to pass
a calibrated broadcast quality signal at optimum levels. Signal video and
black output adjustments are available to correct deficiencies in the input
signal.
Once any video or black adjustments are made, it is recommended to save
these settings on the User Settings web page (
). If the format is reselected from the pulldown, the Level values
will return to the factory defaults for that format.
Timing/Blanking Adjustments
The following adjustments can be made to the signal that affect timing and
blanking:
•
Horizontal delay – adjust the amount of horizontal delay in ns,
•
SAV/EAV positions – set the position of SAV/EAV (start active
video/end active video),
•
Sync source – set the sync source of the module as Y/G Channel or
External, refer to
below, and
•
Vertical blanking – set vertical blanking to Short (525 and 625 = 9 lines)
or Wide (525 = 19 lines, 625 = 25 lines).
Using External Sync
The External Sync source is intended to provide sync when the Y/G com-
ponent signal does not contain sync. The module is not intended to provide
auto-timing or frame sync functions. Allowable horizontal and vertical
phase differences between the Y/G signal and the external sync signal vary
depending upon the presence of sync in the Y/G signal.
provides
the phase difference tolerances. Exceeding these tolerances can produce an
incorrect output signal.
Within the tolerances shown, phase adjustment can be made using the
SAV/EAV (start active video/end active video) and output video delay
line adjustment settings described in
Local On-board Module Configuration
. Function F5, 2nd bank, adjusts output horizontal phase by
setting the position of active video in the digital output within a ± 400 ns
window. Function F4, 2nd bank provides output line delay of up to 2.5 lines
in 37 ns increments.
Table 3. Adjustable Phase Difference Between Y/G and External Sync
Y/G Input
H Phase
Difference
V Phase
Difference
When Out of Tolerance
With Y/G sync
< ± 400 ns
0
Select Y/G channel for Sync Source (F2, 2nd bank),
compensate using Output delay (F4, 2nd bank)
No Y/G sync
< ± 5 µs
Up to two lines
N/A