GRASS VALLEY 1200, Installation And Service

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2-41
Analog Output Option Installation
Adjusting Analog Output Gain
The format selection jumpers provide a convenient way to select signal
levels that are accurate enough for most monitoring purposes. However, if
your application demands precise signal levels, you may need to adjust
signal gain using the gain adjustments on the Analog Output mezzanine
board:
1. Place the Mixer module on the Module Extender, and select 100% Color
Bars as the Program and Preview switcher output.
2. Connect a waveform monitor or oscilloscope to the analog output
BNCs on the back of the frame. Terminate the scope or monitor inputs
with 75 Ohms.
3. Observe the analog output on the scope or monitor and adjust the Y,
R-Y, and B-Y gain controls on the Analog Output board to match the
waveform to the desired signal levels shown in Figure 2-29 for color
difference signals or Figure 2-30 for RGB signals. The gain adjustment
trim pots are accessible through holes in the back of the 064815 Analog
Output mezzanine board with the mezzanines installed on the Mixer
module.
NOTE:
In RGB formats, the gain controls are somewhat interactive. For best
results, adjust Y gain while observing the green output so that the white color bar
achieves the specified level. Then observe the red output and adjust R-Y gain for
equal level bars having red content; similarly, observe blue output and adjust B-Y
gain for equal level bars.