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im Vertrieb von
Setting Up Genlock and Vertical Interval Switching
Genlock setup
www.camboard.de
CAMBOARD Electronics
For vertical interval switching (to allow clean switching between signals from
several devices during the vertical blanking period of each signal), a composite
sync signal can be applied at the Genlock In connector, and also passed to another
device via the Genlock Out connector.
If the genlock connectors are used only for vertical interval switching, no horizontal
or subcarrier phase adjustments are required.
Genlock differs from simple vertical interval switching in that an external device (a
black burst generator) generates a reference sync signal for the system, and every
device that uses that signal has its output signal's horizontal and subcarrier phases
adjusted to exactly match that of the generator, allowing precise timing and full
synchronization. Genlocked systems produce cleaner switches between inputs
than do those without this type of synchronization.
An oscilloscope is required for genlock setup, and a vectorscope is recommended.
Waveform monitors of types other than a vectorscope may give the appearance that
timing is adjusted correctly when it is 180 degrees out of phase, which will result in
incorrect colors or picture artifacts.
All equipment in the system must be powered up and turned on for at least
15 to 20 minutes before genlock setup adjustments can be made and before the
equipment is used in a genlocked application.
To synchronize the PIP's video output with a genlock signal, follow these steps:
1.
Power up and turn on all the devices that will use the genlock signal.
The devices must be on for at least 15 to 20 minutes before proceeding
with any adjustments.
2.
Connect the active timing source signal to the Genlock In connector on
the rear panel.
3.
Connect the video input devices to the PIP, as described previously in
this chapter.
4.
Connect the oscilloscope ("scope") probe A to the Genlock Out connector.
This will provide the scope's reference signal. In order to avoid altering
the genlock signal, use the cabling configuration that will be used in the
installation. Either connect the genlock signal cable from the scope to the
next device in the system to be timed, or provide 75 ohm termination at
the scope's genlock output.
5.
Connect scope probe B to the PIP's composite video output connector.
Using the instructions for the scope you are using, set the scope to view
6.
the signals' horizontal phases. Adjust the horizontal phase until there is
no (0°) difference between the composite video output's horizontal sync
phase and the genlock signal's horizontal phase. See "Genlock
configuration menu (PIP 444 only)" in chapter 3, "Operation", and
"Oscilloscope displays" later in this chapter for details on adjusting the
horizontal phase.
7.
Set the scope to view the subcarrier signals. Adjust the subcarrier phase
until there is a zero phase difference between the genlock signal and the
NTSC/PAL output. See "Genlock configuration menu (PIP 444 only)" in
chapter 3, "Operation", and "Oscilloscope displays" later in this chapter
for details on adjusting the color subcarrier phase.
Tel. 07131 911201
PIP 422 and PIP 444 Picture-in-Picture Processors • Installation
Fax 07131 911203
ce-info@camboard.de
2-7
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