What is monitor video bandwidth and why is it important?
(From: Bob Myers (myers@fc.hp.com)). Video bandwidth is an indication of the frequency range over which the monitor’s video amplifiers are capable of doing their job, which is to translate the video signal at the monitor inputs (about 0.7 volt, peak-to- peak) to something like 35-40V peak-to-peak at the CRT cathodes. Higher bandwidths ARE better, UP TO A POINT. The bandwidth required is NOT given by multiplying the numbers in the format (what most call the “resolution”) by the refresh rate; even allowing for the required blanking time, what THAT gives you is the pixel rate or “pixel clock”. As the fastest thing that happens in a video signal is one dot on followed by one dot off, the fastest FUNDAMENTAL frequency in the video signal is half the pixel clock. Normally, you might think you’d want to cover some of the harmonis to “sharpen up” the pixel edge, but that’s actually less important than you might think (in part due to the fact that the CRT screen itself, being made up of discret
(From: Bob Myers (myers@fc.hp.com).) Video bandwidth is an indication of the frequency range over which the monitor’s video amplifiers are capable of doing their job, which is to translate the video signal at the monitor inputs (about 0.7 volt, peak-to- peak) to something like 35-40V peak-to-peak at the CRT cathodes. Higher bandwidths ARE better, UP TO A POINT. The bandwidth required is NOT given by multiplying the numbers in the format (what most call the “resolution”) by the refresh rate; even allowing for the required blanking time, what THAT gives you is the pixel rate or “pixel clock”. As the fastest thing that happens in a video signal is one dot on followed by one dot off, the fastest FUNDAMENTAL frequency in the video signal is half the pixel clock. Normally, you might think you’d want to cover some of the harmonis to “sharpen up” the pixel edge, but that’s actually less important than you might think (in part due to the fact that the CRT screen itself, being made up of discret
