n350bq@tamuts.tamu.edu (Duane Fields) (08/04/90)
I am about to buy a 3000 and a mistibushi diamondscan monitor. Has anyone ever used this combination? A friend of mine believes that vga monitors will always have the little black boarder, and that the 1950 may be a specially designed system, made to eliminate the border in overscan mode. Anyone know?? Duane
mjl@ut-emx.UUCP (mjl) (08/05/90)
In article <7137@helios.TAMU.EDU> n350bq@tamuts.tamu.edu (Duane Fields) writes: >I am about to buy a 3000 and a mistibushi diamondscan monitor. Has anyone >ever used this combination? A friend of mine believes that vga monitors will >always have the little black boarder, and that the 1950 may be a specially >designed system, made to eliminate the border in overscan mode. >Anyone know?? I just finished setting up my new A3000 with my diamondscan monitor, and am pretty pleased with the result. A VGA -> multisync cable is required; this didn't come with the diamondscan I bought (about a year ago). Basically it just passes the RGB signal & ground along with some sync signals. Anyhow, the adjustment of the A3000 de-interlacer went smoothly, as described in the manual. The display passed all tests. As to your question re the border: yes, there is a _small_ black border around the screen with the de-interlacer enabled, even with the diamondscan adjusted to maximum screen size both horizontal and vertical. With the de-interlacer disabled, the maximum screen size is much "larger" and will completely cover the visible screen area if desired (same # of pixels, though). I have no idea why this occurs (may be important for video applications). I have a feeling the "border" you mention is much larger for IBM systems since you can't use the overscan region. I've been able to get the maximum overscan allowed by AmigaDos 2.0. However, when you do this the top scan line will flicker if it's any other color than black. Setting the standard overscan region down 1 or 2 pixels from the top maximum solves this problem. The only thing I'm less than happy about is that there is a lot of flicker when scrolling multi-color text (say, blue mixed in with black, using the standard 2.0 colors) on a 7xx by 4xx screen through the de-interlacer (can't really say 'interlaced' any more, I guess). I have a feeling this has more to do with limitations of the blitter performance than anything else (is this right?). Maurice LeBrun Institute for Fusion Studies mjl@fusion.ph.utexas.edu University of Texas at Austin
cmcmanis@stpeter.Eng.Sun.COM (Chuck McManis) (08/07/90)
In article <7137@helios.TAMU.EDU> (Duane Fields) writes: >I am about to buy a 3000 and a mistibushi diamondscan monitor. Has anyone >ever used this combination? A friend of mine believes that vga monitors will >always have the little black boarder, and that the 1950 may be a specially >designed system, made to eliminate the border in overscan mode. >Anyone know?? Believe it or not, this message is a milestone for me. It signifies that video display hardware has come full circle, now I believe it shall repeat again. First a little video tidbit : Monitors are made of glass, and glass in not flat. There is a "sweet spot" in the monitor where all the dots being displayed are of uniform size and intensity. The farther from the center of the tube you go, the more difficult it becomes to get uniform pixels. This is due to two reasons. The first is that the glass must begin curving backward so that it can make that sharp turn that defines the "face" of the tube, and secondly as you deflect the electron beam further and further it becomes more difficult to control and begins to hit the phospor at an odd angle making it more difficult to maintain consistent intensity. In 1978 I had a Digital Group 4 board Z80 system with the TVIF interface. This interface was 16 lines of 64 characters on a converted TV set. I _hated_ the fact that the Characters at the beginning and end of the lines were wider than the characters in the center of the screen. I tried everything I could to tighten it up so that all 64 characters would land on the linear region of the tube. I was never completely successful. During those years it became somewhat prestigious to get 64 characters on the screen (or, hold me back, 80 characters) and not have to go into the "yukky overscan region" of the tube. Now, of course, we have people who want to get the "whole" picture and want edge to edge visibility! (Not worrying of course that the pixels on the edge are not linear.) Finally, most video display devices can be adjusted internally to display out to the edges of the screen. Usually there is a "width" slug in the hoizontal output stage that can be tweaked. Changing this can and does void your warranty and a lot of other adjustments usually are tied to this one (changing the width can change the high voltage level which can change the brightness of the beam) Don't open up your monitor unless you are sure you know what you are doing. Otherwise you may just make it worse and end up having to get the entire monitor recalibrated by a service tech. -- --Chuck McManis Sun Microsystems uucp: {anywhere}!sun!cmcmanis BIX: <none> Internet: cmcmanis@Eng.Sun.COM These opinions are my own and no one elses, but you knew that didn't you. "I tell you this parrot is bleeding deceased!"
aduncan@rhea.trl.oz.au (Allan Duncan) (08/07/90)
From article <140231@sun.Eng.Sun.COM>, by cmcmanis@stpeter.Eng.Sun.COM (Chuck McManis): ... > make that sharp turn that defines the "face" of the tube, and secondly > as you deflect the electron beam further and further it becomes more > difficult to control and begins to hit the phospor at an odd angle making > it more difficult to maintain consistent intensity. > > In 1978 I had a Digital Group 4 board Z80 system with the TVIF > interface. This interface was 16 lines of 64 characters on a converted > TV set. I _hated_ the fact that the Characters at the beginning and end > of the lines were wider than the characters in the center of the screen. > I tried everything I could to tighten it up so that all 64 characters > would land on the linear region of the tube. I was never completely > successful. During those years it became somewhat prestigious to get > 64 characters on the screen (or, hold me back, 80 characters) and not > have to go into the "yukky overscan region" of the tube. I fondly remember a 7" 70 degree unit that would give you 180 crisp and even characters if you wanted! It really comes down to deflection angle and correction electronics (domestic units are 110 degrees, "high resolution" are 90 degrees). The lower angle units have long tubes that poke out the back, and correction electronics cost money. If I pay 4 grand for a 25" data monitor, I expect (and get) uniform performance right out to the screen mask edge. Lesser amounts give lesser performance. Allan Duncan ACSnet a.duncan@trl.oz (03) 541 6708 ARPA a.duncan%trl.oz.au@uunet.uu.net UUCP {uunet,hplabs,ukc}!munnari!trl.oz.au!a.duncan Telecom Research Labs, PO Box 249, Clayton, Victoria, 3168, Australia.