Tvone C2-1000 Series, Руководство по эксплуатации

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C2-1000 S
ERIES
O
PERATION
M
ANUAL
42
There is a period of time between the end of the Horizontal Sync pulse and the start
of Active Video. This portion of the waveform signal is called the “Back Porch”, a
term originating with the television broadcasting industry and its RS-170A
specification. In practice, this will control where the video image starts on the left
side of the monitor without changing the width of the sync pulse itself (another way to
control where the image area starts). The two parameters control where the back
porch is positioned and they interact to a degree.
By adjusting these parameters, you control the start of the back
porch (with respect to the trailing edge of Horizontal Sync) and
also its width. The place where the Back Porch begins with
respect to the Horizontal Sync pulse and the width of the Back
Porch have a direct bearing on where the active (visible) portion of the image begins.
Do not attempt this adjustment without monitoring the results with an oscilloscope.
There are standards for all current computer and broadcast resolutions that specify
the correct width of both Vertical and Horizontal synchronizing pulses.
If you are creating a special, non-standard resolution, you may wish to adjust the
pulse width to fit your new requirements. The H/V Sync screen is where that is
accomplished.
Like the H/V Start adjustment, you must use an oscilloscope when
making these adjustments so that you know exactly how many
milliseconds or microseconds of pulse width you have created.
The numbers shown are relative numbers and not an actual time
measurement.
Sync can be either negative polarity or positive polarity. To further complicate
things, it is possible that you may want to make the Horizontal Sync polarity different
from the Vertical Polarity. This control allows you to make that change. You have
four possible selections:
+H+V
-H+V
+H-V
-H-V
800 x 600 60 Hz
H/V Start [ 88] x 23
800 x 600 60 Hz
H/V Sync [ 128] x 4
800 x 600 60 Hz
Sync polarity [+H+V]