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3.3 Adjusting for Optimum Picture Quality
3.3.2 Frequency & Phase—Computer
Sources
These adjustments match the internal dot clock to the external signal. An external checkerboard
pattern is best, and this must come from the source computer. This should be done with Sharpness
on.
These two adjustments require an external
checkerboard pattern. The instructions for
making this pattern with Paint in Windows 95
are in Section 7.9, page 7-18.
In an emergency, you can get a pretty good
checkerboard pattern from the Windows shut-
down screen. First, minimize all applications
and use a plain white background for the Desk
Top. Select Start, then Shut Down, but don't go
any further. The desktop now has a pattern in
which every other pixel is black.
With MAC ON-SCREEN LEDS 8.0, look for
a checkerboard pattern in File, Control Panel,
Desktop Patterns.
✎
Note: This process is only for computer sources,
PC1 or PC2. These menus don't work, if the
selected source is C-Video or S-Video.
Always do Frequency before Phase, because the
phase adjustment is meaningless unless the
frequency is correct. Here is the procedure:
1. Generate a checkerboard pattern on the
source computer.
2. On the remote, press
3. Highlight Misc Control and press
.
ENTER
4. See that Sharpness has an x in it. If it
doesn't, highlight it and press
5. On the remote, press
6. Adjust Frequency with the right-left arrow
keys. When the frequency is wrong, you
will see vertical bands of noise in the
picture. (If there is horizontal streaking as
3 - 22
.
MENU
.
ENTER
.
FREQ
well, ignore that for now.) As you change
frequency, the number of bands will
increase or decrease. At one frequency,
there will be no bands. That's what you
want. All displays using the same
computer source, even with different video
cards, will have the same Frequency
number at the end of this process.
✎
Note: It doesn't matter what the Frequency number
is. This is just a reference number between
000 and 127. It is not the frequency.
7. Press
.
PHASE
8. Adjust Phase with the right-left arrows.
When the phase is wrong, you will see
horizontal streaks of noise. As you change
the Phase the noise will increase or
decrease.
✎
Note: It doesn't matter what the Phase number is.
This is just a reference number between 000
and 031.
9. Try to adjust for no noise at all. It may
not be possible to eliminate all of it, in
which case reduce it to a minimum.
Sometimes within the 000–031 range of
the Phase number, there are two places
where noise is eliminated. Run the Phase
number up and down the scale. Find the
area where the horizontal noise is reduced
over the widest range of Phase numbers.
Set the Phase in the middle of this range.
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