grunau_b@husc4.UUCP (02/14/87)
Forgive my ignorance, but all this recent discussion about the Amiga's NTSC standard has got me confused. Several people on the one hand have been wanting the Amiga to allow a non-interlaced high-resolution (e.g. 400 vertical) display, apparently because they find both options of flicker and high-persistance smear to be unacceptable. Other people believe that it is more important to keep the Amiga within NTSC standards. But this confuses me -- I understand that NTSC standards will not allow a 640 by 400 non-interlaced display; but I thought the Amiga was famous for having not only NTSC output, but also digital and analog RGB, which are, unless I am confused, NOT NTSC-compatible. Could somebody enlighten me on the distinction? Also -- one last piece of confusion: I don't understand why the Amiga lacks normal TTL output for a high-resolution monochrome monitor; I assume you can hook a mono monitor up to an Amiga if you choose; what happens when you try to get high-resolution? thanks, JJMG grunau@husc4.UUCP or --- !seismo----- \ --- !rutgers----- !husc6!husc4!grunau / --- !decvax!ihnp4 or For BITNET, I believe the hostname is "harvard".
farren@hoptoad.UUCP (02/15/87)
In article <1235@husc6.UUCP> grunau_b@husc4.UUCP (Justin J. M. Grunau) writes: >[. . .] but I thought the Amiga was famous for having not only NTSC >output, but also digital and analog RGB, which are, unless I am confused, >NOT NTSC-compatible. Could somebody enlighten me on the distinction? > You are, of course, correct - the RGB signals are not NTSC compatible (at least, not with the NTSC standard describing the standard television composite signal - they are compatible with standard video signal levels as described elsewhere). However, it is important to realize that no matter which graphics mode you select, the signal out of the composite video connector IS NTSC stan- dard, and can be taped. 320 X 200 X 32, 640 X 400 X 16, doesn't matter. If the Amiga offered (say) 1024 X 1024 X 4096, then there would be no way to make that composite output compatible, thus no way of taping or transmitting the signal 'straight'. >Also -- one last piece of confusion: I don't understand why the Amiga lacks >normal TTL output for a high-resolution monochrome monitor; I assume you can >hook a mono monitor up to an Amiga if you choose; what happens when you try >to get high-resolution? > There isn't any such thing as a "normal TTL output", unless you are talking about the phrase usually used in connection with an IBM PC monochrome monitor. This is only "normal" in the PC world - it has a distinctly non- standard scan rate. You can use a mono monitor hooked up to the composite video output; these have existed for Apples and Atari 8-bitters for years. If you find one which allows interlace, and has a fairly high persistance phospher, it will work just fine in high-res mode. I've tried it with an old Motorola monitor I've got, and it worked real well - flicker just went away (but, then, so did color). -- ---------------- "... if the church put in half the time on covetousness Mike Farren that it does on lust, this would be a better world ..." hoptoad!farren Garrison Keillor, "Lake Wobegon Days"
grr@cbmvax.UUCP (02/17/87)
In article <1235@husc6.UUCP> grunau_b@husc4.UUCP (Justin J. M. Grunau) writes: > >But this confuses me - I understand that NTSC standards will not allow a 640 by >400 non-interlaced display; but I thought the Amiga was famous for having not >only NTSC output, but also digital and analog RGB, which are, unless I am >confused, NOT NTSC-compatible. Could somebody enlighten me on the distinction? While the RGB outputs are not really NTSC compatible, the sync format and timing are relatively NTSC complient. This makes possible simple encoding to NTSC composite video and RF modulation, allowing the Amiga video output to be displayed on any normal color monitor or TV set. If you do not have this degree of compatibility, then either the video encoding becomes very complicate or the system must 'shift gears' between various modes. (Atari ST and various PC display cards...) >Also -- one last piece of confusion: I don't understand why the Amiga lacks >normal TTL output for a high-resolution monochrome monitor; I assume you can >hook a mono monitor up to an Amiga if you choose; what happens when you try to >get high-resolution? There's not much standard about TTL monitors - except perhaps in the PC World. They run at 50Hz / 18KHz scan rates which is sort of compromise between the phosphor characteristics, cheap monitor technology and video card design. You can however, plug a cheap ($70-100) monochrome *composite* monitor into the composite output of your amiga. A long persistance phospher makes the flicker go away, though you get a bit of smear while scrolling. -- George Robbins - now working for, uucp: {ihnp4|seismo|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@seismo.css.GOV Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)