Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84 / ST 1.0; site saber.UUCP Path: utzoo!linus!decvax!decwrl!sun!saber!skinner From: skinner@saber.UUCP (Robert Skinner) Newsgroups: net.micro.amiga Subject: Re: on interlace Message-ID: <1767@saber.UUCP> Date: Fri, 13-Sep-85 13:59:44 EDT Article-I.D.: saber.1767 Posted: Fri Sep 13 13:59:44 1985 Date-Received: Sun, 15-Sep-85 04:56:57 EDT References: <3629@topaz.RUTGERS.EDU> Organization: Saber Technology, San Jose, CA Lines: 50 > From: keithe%tekgvs%tektronix.csnet@csnet-relay.arpa > > > >> I can't figure out what an interlaced monitor is. > >> What will look better in the Amiga: 640x400, or > >> 640x200? Does it matter? > > >The price one pays is flicker, since screen sweeps are only done 30 > >times a second, as opposed to 60 times a second during non-interlace. > >Thus a higher persistance monitor is needed to eliminate flicker. > > Well, not really... One of the *advantages* of interlace is that > flicker is reduced. A "half" frame is generated every 1/60 of a second, > but that half-frame is distributed over the entire face of the crt. > Then, 1/60th of a second later, the intervening lines are drawn for the > other half of the frame. (P.S., each half-frame is referred to as a > "field.") So the eye thinks it's getting refreshed 60 times every > second - because it can't distinguish the separate lines - instead of > at a 30 per second, which would be very noticeably flickering. > > Keith Ericson at TekLabs (resident factious factotum) > Tektronix, PO 500, MS 58-383 > Beaverton OR 97077 > (503)627-6042 > uucp: [ucbvax|decvax|ihnp4|(and_many_others)]!tektronix!tekgvs!keithe > CSnet: keithe@tek > ARPAnet: keithe.tek@rand-relay NO, NO, NO!! If you draw a lone horizontal line on the screen, it *will* flicker, because it is only refreshed 30 times a second. Even if you are thinking about large painted areas it doen't work. The two fields are (ideally) displaced by the size of a scan-line (Or you don't actually get the required resolution). This usually results in a lower overall intensity, unless you have very long persistence phosphor. But very long persistence phosphor "streaks" when you try to do dynamic frames, i.e. real-time graphics. You're not in the monitor or graphics design groups are you? Non-interlaced Forever... ------------------------------------------------------------------------------ .. man then went on to prove that black was white, and was promptly killed at the next zebra crossing. Name: Robert Skinner Snail: Saber Technology, 2381 Bering Drive, San Jose, California 95131 AT&T: (408) 945-0518, or 945-9600 (mesg. only) UUCP: ...{decvax,ucbvax}!decwrl!saber!skinner ...{amd,ihnp4,ittvax}!saber!skinner