C2-6104A O
PERATION
M
ANUAL
41
The H.freq.fine (Horizontal Sync Frequency) adjustment provides the option for
changing the Horizontal Sync timing Frequency in 1 Hz steps. Use this option to
fine tune after using the course adjust.
Please note that the internal sync generator may be unable to generate the exact
frequency you want.
This option changes the total number of image pixels on one line of monitor video
including the Horizontal sync pulse and blanking time. This is normally in a multiple
of 8. It is very important to get this value correct, or many digital display devices,
such as TFT monitors, will display an image with an odd moiré effect – such as soft
vertical bands spread evenly across the image.
This menu controls the total number of lines of video present in the image which
includes the vertical Sync pulse, the blanking period and the active video. Changing
this option affects the final vertical sync frequency.
A video frame includes both the active area, the portion of the image normally
containing useful visual information, and a resolution value for a given display
standard which only expresses the number of pixels visible in an image.
The well-known 800 x 600 computer resolution standard simply means that there
are 800 pixels/line visible horizontally and there are 600 lines visible vertically.
This item provides a way to change the number of active pixels and lines.
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
800 x 600 60 Hz
Clks/l [1056] = 40.000MHz
800 x 600 60 Hz
Lines/f [ 628] = 60.317 Hz
800 x 600 60 Hz
H/V active [ 800] x 600
800 x 600 60 Hz
H/V Start [ 88] x 23
