Operation, cont’d
VSC 200/200D/300/300D Operation
3-8
6.
Using the instructions for the scope you are using, set the scope to view the
signals’ horizontal phases. From the
phase adjust
screen of the
configuration
controls
menu, adjust the scan converter’s horizontal phase control until there
is no (0º) difference between the composite video output’s horizontal sync
phase and the genlock signal’s horizontal phase. See “Oscilloscope displays”
on page 3-8, and “Configuration controls menu” on page 3-3.
7.
Set the scope to view the subcarrier signals. From the
phase adjust
screen of
the
configuration controls
menu, adjust the scan converter’s subcarrier phase
until there is a zero phase difference between the genlock signal and the
NTSC/PAL output. The Genlock LED should light.
If the Genlock LED does not light at this point, either adjust the horizontal or
subcarrier phases further, or use a different genlock source.
The subcarrier adjustment range is +/- 180 degrees from 0 for a total
adjustment range of 360 degrees.
8.
View the horizontal phases again. If the phase difference is not zero, repeat
steps 6 and 7 until the settings do not change.
If the Genlock LED does not light at all when genlock is active and the
horizontal and subcarrier phases have been adjusted to match the genlock
signal, do not continue with this procedure. A different, more stable or time-
base-corrected sync signal must be used for the genlock timing source.
9.
After the settings are stable and the Genlock LED lights, disconnect the
oscilloscope, and reconnect the genlock cables and terminator to the proper
devices in the system.
10.
Check the display for proper colors and for undesirable artifacts in the image.
Make adjustments as necessary. After the genlock timing has been adjusted, it
should not require readjustment when changing to a new computer video
signal input.
11.
If other scan converters are part of this genlock daisy chain, connect the
oscilloscope to each device, and repeat this procedure.
Oscilloscope displays
What you see on the oscilloscope while adjusting the scan converter to match the
genlock signal depends on the type of signal used, the type of oscilloscope, and the
procedure the scope requires. This section shows some examples of oscilloscope
displays.
Figure 22 shows the genlock input signal (top) and an out-of-alignment NTSC
composite sync output signal (bottom) displayed on a waveform monitor to check
for alignment. When the phases are aligned, the wave peaks on the bottom
waveform should line up with those in the reference signal above it.
im Vertrieb von
CAMBOARD Electronics
www.camboard.de
Tel. 07131 911201
Fax 07131 911203
