Path: utzoo!attcan!uunet!unsvax!jimi!tahoe!apple!hercules!caveh From: caveh@csl.sri.com (Caveh Jalali) Newsgroups: comp.arch Subject: Re: why is 33 MHz a popular number? Message-ID: <22660@hercules.csl.sri.com> Date: 2 Dec 90 01:17:54 GMT References: <1990Nov28.030500.16103@mozart.amd.com> <11214@pt.cs.cmu.edu> <1554@ftc.framentec.fr> <1990Dec1.152532.16888@murdoch.acc.Virginia.EDU> Sender: usenet@csl.sri.com Organization: Computer Science Lab, SRI International, Menlo Park, CA Lines: 23 In article <1990Dec1.152532.16888@murdoch.acc.Virginia.EDU> clc5q@shamash.cs.Virginia.EDU (Clark L. Coleman) writes: >In article <1554@ftc.framentec.fr> ndoduc@framentec.fr (Nhuan Doduc) writes: >... >The first three have the relationship as 2,3 and 4 times 2.385 MHz, so that >is no problem. Deriving them all from 15.31 MHz is tough. So I assume you meant >14.31 MHz. > >So, what was the famous communications port that worked at 14.31 MHz, just for >my own curiosity ? 14.31 MHz probably has nothing to do with communication ports (necessarity). that's 4x the colorburst frequency. aparently, the colorburst frequency was a very popular choice in the early computer days because it was easy (cheap) to get that crystal, not to mention the fact that it could be used for other purposes simultaneously. i think it was used in color TVs or something to separate the color signal from the rest of the signal. so, if your computer generated a color video signal, you only needed one crystal to generate the signal as well as clock the CPU. -- 00c -- caveh@csl.sri.com "X is not a letter, it's a sentence." Brought to you by Super Global Mega Corp .com