10 Pelco Manual C1903M (4/99)
V-PHASE ADJUSTMENT
Vertical phase adjustment is required only if your system uses two or more cameras.
The vertical phase can be manually adjusted within the range of approximately -90 degrees
to +90 degrees (refer to Illustration H).
I
Vertical Phase
H
AC Line Lock Adjustment
Vertical phase adjustment is not vertical roll adjustment. Each camera is adjusted to the
AC zero crossover point at the factory. Problems arise, however, especially in larger
systems, when:
1. Switching rapidly between widely separated cameras with manual or sequential
switchers.
2. Switching between cameras not operating off the same phase of the AC line. When
using a single power source, make sure each AC line lead is connected to the same
input terminal on all cameras.
3. Both of the above.
In such cases camera switching may produce what appears to be vertical roll on the
monitor between the two views (Illustration I).
To adjust the vertical phase:
Turn the V-phase pot (while switching as rapidly as possible between the two camera
views) to adjust the relative phase angle between the two cameras and the point at which
one camera synchronizes to the AC line with respect to the other. Adjust the pot until the
switching is clean and there is no vertical roll or flip.
3)
1) 2)
4)
-90°
0°
+90°
-90°0°+90°
2)
3)
4)
1) Camera switcher
Monitor
Vertical drive signal
Adjustable range