Stand back a meter (3 feet) from the screen
and look about 60 cm (2 feet) above the screen. The image on the
screen will be in the lower periphery of your vision. You will be able to
see visible flicker if the refresh rate is low.
Repeat the experiment with the refresh rate set to 75 Hz, and you??™ll
see why users complain about eyestrain and headaches at the lower
speeds.
This experiment will usually fail on an LCD.
The HorizSync range is specified in kHz (thousands of cycles per second).
You should avoid guessing at the HorizSync and VertRefresh values; look them up in
the monitor manual or on the manufacturer??™s web site. As a last resort, perform a
general web search to find the values. On some monitors??”especially older ones??”
you can cause serious damage by using the wrong frequency. Once you know the
correct values, do yourself a favor and mark it on the back of the monitor.
3.14
3.14 Configuring a Monitor??™s Scan Rates 61
If you are using a video splitter to connect two monitors, use the intersection of the
two monitors??™ frequency ranges. Pick the higher of the two lower range limits, and
the lower of the two upper range limits.
For example, if you are connecting a video monitor and a projector, and the monitor
has a HorizSync range of 31.
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