Extron Electronics VSC 900_900D User Guide - Manual (Page 15)

2-7 VSC 900/900D • Installation and Operation
5. Connect scope probe B to the VSC’s composite video output connector.
6. Using the instructions for the scope you are using, set the scope to view
the signal’s horizontal phases. Adjust the horizontal phase by rotating
the horizontal Adjust (
) knob (see the “Genlock Menu” section in
this chapter). 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 the “Oscilloscope
displays” section in this chapter.
7. Set the scope to view the subcarrier signals. Adjust the sub phase by
rotating the vertical Adjust ( ) knob until there is a zero phase
difference between the genlock signal and the NTSC/PAL output (see
the “Genlock menu” section in this chapter).
8. View the horizontal phases again. If the phase difference is not zero,
repeat steps 6 and 7 until the settings do not change.
9. Once the settings are stable, disconnect the oscilloscope, and reconnect
the genlock cables.
10. Check the display(s) for proper colors and for undesirable artifacts in
the image(s). Make adjustments as necessary.
11. If other VSCs 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 VSC 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.
The following diagram 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.
Figure 2-4 — Superimposed waveforms