Extron Electronics PA 300 - Manual (Page 18)

PA 300 Peaking Amplifier • Adjusting the Display
Adjusting the Display
3-2
Signal Compatibility
The PA 300 processes VGA-UXGA, RGBHV, RGBS, RGBsB,
RsGsBs, HDTV, and component video signals.
Potentiometer Adjustments
The PA 300 achieves superior amplification by using two
independent peaking potentiometers: LF for streaking
adjustment and HF for detail adjustment.
The goal in adjusting the PA 300 Gain and Peaking
potentiometers is to produce a sharp image (i.e., an image free
of streaking or smearing) on the attached display.
An oscilloscope is required for the most accurate gain
adjustment, but gain can also be adjusted by observation. The
following instructions explain how to adjust the gain with
and without the use of an oscilloscope. An oscilloscope is not
necessary for the peaking adjustment.
Adjusting gain with an oscilloscope
To adjust the Gain potentiometer using an oscilloscope:
1.
Remove the cable from the source and attach a VTG 300
test generator to this cable.
2. Use the White Field test pattern for the VTG 300 setting.
3. Remove the far end of the cable from the projector and
attach the oscilloscope using 75 ohm termination.
4. Use an Extron Tweeker to adjust the Gain potentiometer
for a 0.7 Vp-p reading from white (top) to black (bottom) of
the waveform.
5. Once gain is successfully adjusted, replace the source and
display cables.
6. See "Adjusting the peaking" on the following page.
Adjusting gain without an oscilloscope
Use an Extron Tweeker to turn the Gain potentiometer until the
image reaches the desired level of brightness.