> > The total memory bandwidth is 1.6*10**9 pixels per second, while the > > max video for one head is only 330*10**6. > > > >> Note that in theory if we use shunt peaked video out buffers that > >> #2 would be twice #1 for analog video but it would be normal to > >> have an additional frequency margin. > > NO, that is wrong pixel resolution is twice line resolution so it would > theoretically be 1/2. I am always confusing that.
Yes, I believe in TV style video, "lines" really means "line pairs" (e.g. a black line plus a white line) if you are talking about horizontal resolution, but the same as pixels if you are talking about vertical resolution. Nice and confusing. > Yes the bandwidth of the analog video amplifiers. So, if we are going > to have a max pixel clock rate of 330 MHz, do we really do need the > 1.8GHz video amp for maximum sharpness. Also, we should consider the > specs of available monitors since there isn't much point in having a > bandwidth significantly wider than the monitor. Unfortunately, most > companies don't seem to give out the bandwidth of the monitor's video > amps. Monitor specs seem to include: "Maximum Input Video Bandwidth" > and I don't know if they mean digital (dot clock) or analog (video amp). > I think that they mean dot clock which tells us nothing. >From what little I can figure out, a CRT monitor's bandwidth is probably not the limiting factor. More likely the limiting factor is the ability to focus the beam tightly, and/or the pitch of the mask. > And next question, is the monitor input 50 ohm or 75 ohm. RS-170 is 75 > ohm. The schematic shows a 49.9 (standard 1% value but some suppliers > also sell actual 50s) ohm termination resistor. I think that this is an > error, it should be 75 ohm for R90, R100, & R110. My notes say that computer monitors are 75 Ohm. _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
