Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site uscvax.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!sdcrdcf!uscvax!tli From: tli@uscvax.UUCP (Tony Li) Newsgroups: net.periphs Subject: Re: terminal noise Message-ID: <1257@uscvax.UUCP> Date: Sat, 8-Dec-84 03:45:36 EST Article-I.D.: uscvax.1257 Posted: Sat Dec 8 03:45:36 1984 Date-Received: Sun, 9-Dec-84 06:16:14 EST References: <36@mot.UUCP> Organization: CS&CE Depts, U.S.C., Los Angeles, CA Lines: 30 > [Hic sunt dracones] > There are NO dragons here. Even if things do keep draggin' on. (Sorry, I couldn't resist.) > I am typing this at a Televideo 950 terminal and am listening to > a high-pitched continuous sound emanating from the terminal. > It is near the upper limit of my hearing, maybe 15-17 kHz, > and is loud enough to be distracting. I mentioned this to someone else > and he said that all terminals do that. Maybe his hearing is better > than mine, because I never heard it on any other terminal. > I seem to remember a letter to the editor of Byte magazine a year > or two ago complaining about the same thing. Can any of you hardware > types explain this sound? Is it indeed universal? Are the makers of > terminals aware of this and do they try to minimize it? For me, > this adds a new criterion for the selection of a terminal. > This is the flyback transformer, and is a necessity for generating the HV that your screen needs. Yes, it is universal (for screens - get a plasma display and you'll never hear it). Minimization of the noise is usually by selection of the type of transformer to use. > > Alan Filipski > {allegra | ihnp4 } ! sftig ! mot ! al > -- Tony Li ;-) Usc Computer Science Uucp: {sdcrdcf,randvax}!uscvax!tli Csnet: tli@usc-cse.csnet Arpa: tli@usc-ecl