New answers tagged vga
2
In an analog television set, the vertical and horizontal sync circuits are independent, but both need to derive their trigger signals from a common source. As a general concept, a short "low-going" pulse [which is modulated for broadcast as an increase in signal level] will trigger the horizontal sync circuit, while a long pulse will trigger the ...
4
The CSYNC looks perfectly normal for a standard 576i or 480i composite signal, just like how sync signals on composite video and analog TV transmissions work.
The video signal standards define that serrated equalizing sync pulses are sent at twice the HSYNC rate during the VSYNC and few lines before and after it. This is to allow the VSYNC to be detected ...
9
In analog TV, there was such thing as interlace. Roughly speaking, it kind of increased vertical resolution by putting scanlines of one "halfframe" (the one that lasts 20ms or goes 50 times per second, or, alternatively, 16.6ms and 60 Hz) between the scanlines of previous halfframe (saying scanlines I mean lines lit by electron beam on CRT).
As the ...
5
The concept of 5:4 aspect ratio, and 1280x1024 graphics coordinates, is actually much older than you think.
It dates back at least to the BBC Micro introduced at the end of 1981; it had graphics modes designed around the PAL TVs used in the UK, with 160x256, 320x256, and 640x256 modes, all with a standard coordinate system of 1280x1024 for easy graphics ...
2
As others have said, with limited video memory, that extra video mode gives you flexibility to choose 1280×1024@16bpp over 1600×1200@8bpp depending on your needs.
But it also allows you to choose an optimal refresh rate. If screen flicker bothers you and your monitor or video card is limited to a 72 kHz horizontal scan rate, you might choose 1280×1024@70Hz ...
Top 50 recent answers are included
