From bd628@torfree.net Sat Oct 21 18:17:01 CDT 1995 Article: 119938 of alt.folklore.computers Xref: uchinews alt.folklore.computers:119938 Newsgroups: alt.technology.obsolete,alt.folklore.computers Path: uchinews!vixen.cso.uiuc.edu!uwm.edu!chi-news.cic.net!newsfeed.internetmci.com!news.sprintlink.net!in1.uu.net!van-bc!io.org!torfree!bd628 From: bd628@torfree.net (Bill Markwick) Subject: Re: Mechanical Television Message-ID: Followup-To: alt.technology.obsolete,alt.folklore.computers Organization: Toronto Free-Net X-Newsreader: TIN [version 1.2 PL2] References: <43895i$l1d@maureen.teleport.com> <43cmj1$86b@gap.cco.caltech.edu> <43dk9f$bie@agate.berkeley.edu> <43f8cj$1n1@ixnews4.ix.netcom.com> <44neqn$o33@gatekeeper.tait.co.nz> Sender: news@picker.com Nntp-Posting-Host: 144.54.160.15 Organization: Picker International, Inc. References: <4bg0t3$68o@usenet.ucs.indiana.edu> <4bk1jp$7cu@koala.melbpc.org.au> <4c7id8$jgl@notreally.wwa.com> Date: Mon, 1 Jan 1996 13:43:09 GMT Lines: 39 Status: R In article <4c7id8$jgl@notreally.wwa.com> mikem@wwa.com (Mike Magin) writes: > >That would be the toughest part (assuming they didn't implement the > >decoder with vacuum tubes!). It could not simply be a 1200 rpm > >synchronous motor off the power line - it would need to be driven > >from timing derived from the video sync as TV refresh (and NTSC > >in particular) never was locked to the power line frequency. > That would be a big challenge. > > > >Then you would get a whopping 20 Hz effective color frame rate. > Wouldn't that be a 10 Hz frame rate? NTSC's interlaced. I guess what I was suggesting is going with field sequential. Then the successive R,G,B would actually be from even-odd-even-odd etc. fields. The color flicker rate would be 20 Hz though there might be unusual and undesirable aliasing effects. Using frame sequential would get around these but the 10 Hz color flicker might be even less desirable. Today, one uses a frame buffer and runs the color wheel at 60 Hz (approx) with each frame displayed non-interlaced for 1/180th of a second. This is coming back - the Texas Instruments Digital Micromirror Device (DMD) is an IC with a quarter million or more miromachined tiltable mirrors on top of SRAM memory cells. In one position, light is reflected so that the pixel is bright; in the other the pixel is dark. The response time is microseconds. By controlling the duty cycle of the mirror position in a projection display, one can achieve extremely high quality high brightness full motion full color display. With a single DMD, you use a frame sequential system. Three DMDs can also be used but they you have the additional cost and same of the same kinds of registration problems as multiple CRT based systems. --- sam > -- > Mike Magin 529 ** .5 PGP Pub. key on keyservers > http://sashimi.wwa.com/~mikem/ From carlessp@cadvision.com Fri Jan 5 13:08:08 CST 1996 Article: 127555 of alt.folklore.computers Xref: uchinews alt.folklore.computers:127555 Path: uchinews!news.luc.edu!newsfeed.acns.nwu.edu!math.ohio-state.edu!howland.reston.ans.net!newsfeed.internetmci.com!in2.uu.net!huey.cadvision.com!usenet From: carlessp@cadvision.com (Peter Carless) Newsgroups: alt.folklore.computers,sci.electronics Subject: Re: Anachronisms (was Valves in Russian computers) Date: Fri, 05 Jan 1996 02:54:46 GMT Organization: CADVision Lines: 58 Message-ID: <4ci42j$1pnc@huey.cadvision.com> References: <4bg0t3$68o@usenet.ucs.indiana.edu> <4bk1jp$7cu@koala.melbpc.org.au> <4c7id8$jgl@notreally.wwa.com> NNTP-Posting-Host: cad113.cadvision.com X-Newsreader: Forte Free Agent 1.0.82 Status: R mikem@wwa.com (Mike Magin) wrote: :In article , :Sam Goldwasser wrote: :>In article wa2ise@netcom.com (Robert Casey) writes: :> :>> No, but I do remember seeing in some electronics hobbyist magizine (about :>> 30 years old) describing the conversion of a B&W NTSC TV set by :>> adding NTSC color demodulators and a color wheel! Apparently, the :>> B&W picture tube was driven sequentiallt by switching between red, then :>> green, then blue, then again red, etc. Not sure how the physical color :>> wheel (driven by a motor) was to be syncronized with the color switching :>> on the tube. :> :>That would be the toughest part (assuming they didn't implement the :>decoder with vacuum tubes!). It could not simply be a 1200 rpm :>synchronous motor off the power line - it would need to be driven :>from timing derived from the video sync as TV refresh (and NTSC :>in particular) never was locked to the power line frequency. :That would be a big challenge. :> :>Then you would get a whopping 20 Hz effective color frame rate. :Wouldn't that be a 10 Hz frame rate? NTSC's interlaced. I remember seeing a book years ago that was published in the early 1950's, that described how to convert a black and white tv to color. This was based on the color television system that was standard in the US at the time which I believe was the Columbia system. This system preceded the NTSC system which is the standard today. The Columbia system was vey short lived as I believe the NTSC system was adopted as standard in 1953 or 1954. The Columbia system produced the color image by sending alternate frames of red, blue and green. This is how it was possible to convert a b&w tv to color by installing a rotating disk with red, blue, and green filters in front of the picture tube. The conversion I saw described in this book achieved synchronization by the crude method of having a rope that rubbed against the disk. The viewer was supposed to pull on the rope to slow the disk down, and decrease tension to speed up the disk. Remember that this was in the very early fifties and B&W television was a novelty and color tv was extremely rare. Because of the way that NTSC signal is generated I do not believe that it would be possible to produce a color image from a B&W tube with a rotating disc. BTW, the Columbia color TV system was not compatible with the regular B&W tv sets, and that is one of the reason that the system was so short lived. Broadcasters would have had to transmit 2 signals, one for color tv's and one for b&w tv's. The NTSC system which replaced it is compatible with both color and b&w receivers. Hope this helps. Peter From jones@San-Jose.ate.slb.com Sat Jan 6 19:16:34 CST 1996 Article: 127632 of alt.folklore.computers Xref: uchinews alt.folklore.computers:127632 Path: uchinews!vixen.cso.uiuc.edu!newsfeed.internetmci.com!news.sprintlink.net!news.omnes.net!news.sinet.slb.com!news.San-Jose.ate.slb.com!jones From: jones@San-Jose.ate.slb.com (Clark Jones) Newsgroups: alt.folklore.computers,sci.electronics Subject: Re: Anachronisms (was Valves in Russian computers) Followup-To: alt.folklore.computers,sci.electronics Date: 6 Jan 1996 01:35:24 GMT Organization: Schlumberger Technologies, ATE division, San Jose, Ca. Lines: 48 Message-ID: <4ckjks$8n@k9.San-Jose.ate.slb.com> References: <4bg0t3$68o@usenet.ucs.indiana.edu> <4bhqpe$dg9@newsbf02.news.aol.com> <4bk1jp$7cu@koala.melbpc.org.au> NNTP-Posting-Host: elbert.san-jose.ate.slb.com X-Newsreader: TIN [version 1.2 PL0] Status: R Robert Casey (wa2ise@netcom.com) wrote: : In article <4bk1jp$7cu@koala.melbpc.org.au> gpage@melbpc.org.au (Garry Price) writes: : >In article <4bhqpe$dg9@newsbf02.news.aol.com>, JWISNIA wrote: : >>Anone remember the CBS color wheel TV test xmissions while the FCC was : >>trying to decide which system (CBS or RCA) to standardize on? I remember : >>making a tricolored wheel out of cardboard and gelatin filter stock, : >>putting it on the shaft of an "egg beater" hand drill and cranking away at : >>the right speed while looking through it at a B&W TV running a CBS test : >>program. : > : >I've only just discovered this thread, so appologies in advance if I : >going over old ground. : > : >Anyone ever see the Field-sequential Colour Television Receiver, Wireless : >World, September & October 1971 issues? This used a colour wheel for : >standard PAL system. : > : No, but I do remember seeing in some electronics hobbyist magizine (about : 30 years old) describing the conversion of a B&W NTSC TV set by : adding NTSC color demodulators and a color wheel! Apparently, the : B&W picture tube was driven sequentiallt by switching between red, then : green, then blue, then again red, etc. Not sure how the physical color : wheel (driven by a motor) was to be syncronized with the color switching : on the tube. I wonder if the writers/ editors of that magazine actually : saw this thing working, or even attempted to build it. Nobody in this thread has mentioned that the TV camera on Apollo 11 (which showed the famous "One small step for man, one giant leap for mankind" more- or-less live) was one of the spinning disk variety (probably because of weight - there were no single-tube color cameras in those days). NASA processed the signal to produce an NTSC signal to feed to the TV networks, but the processing took several seconds - if you happened to have a radio going, you heard the words prior to seeing (and hearing) the actions on TV. As for the comments about magazines, it unfortunately seems to go for some of the companies that sell electronics kits these days, too! (I'm in the midst of trying to debug a Ramsey 222 MHz transciever.) Clark -- Disclaimer: The opinions expressed above are mine and not those of Schlumberger because they are NOT covered by the patent agreement! Phone: (602) 345-3638 Internet: jones@San-Jose.ate.slb.com Packet:(not currently available) RF: KI7TU ICBM: 33 20' 44"N 111 53' 47"W Snail: Clark Jones, Schlumberger Technologies, 7855 S. River Pkwy #116, Tempe, AZ 85284-1825 From jcg@qadas.com Wed Jan 10 14:34:04 CST 1996 Article: 128030 of alt.folklore.computers Xref: uchinews alt.folklore.computers:128030 Path: uchinews!vixen.cso.uiuc.edu!howland.reston.ans.net!newsjunkie.ans.net!news.rmii.com!usenet From: Jonathan Griffitts Newsgroups: alt.folklore.computers,sci.electronics Subject: Re: Anachronisms (was Valves in Russian computers) Date: Wed, 10 Jan 1996 11:44:16 -0700 Organization: AnyWare Engineering Lines: 38 Message-ID: <30F40900.4521@qadas.com> References: <4bg0t3$68o@usenet.ucs.indiana.edu> <4bk1jp$7cu@koala.melbpc.org.au> <4c7id8$jgl@notreally.wwa.com> <4ci42j$1pnc@huey.cadvision.com> NNTP-Posting-Host: net76.qadas.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 2.0b5 (Win95; I) Status: R Peter Carless wrote: > BTW, the Columbia color TV system was not compatible with the regular > B&W tv sets, and that is one of the reason that the system was so > short lived. Broadcasters would have had to transmit 2 signals, one > for color tv's and one for b&w tv's. The NTSC system which replaced it > is compatible with both color and b&w receivers. Back in 1978 or so I took a class from a man named James Webb who was a visiting lecturer at U of Colorado. He talked a lot about the early days of TV -- among other things he had been involved in the development of NTSC at RCA. His story was interesting: He said that the original intent at RCA was to build a more sophisticated system than NTSC that involved some digital encoding of the color information (my memory is too fuzzy to remeber the details), and this would have provided much more stable color. However the competing systems (based on rotating color filters) were much easier and quicker to develop and the FCC started its standards selection process before RCA was ready. So over a weekend the RCA crowd kludged together a system using the parts they had already developed and fudging the rest, and this is what became NTSC. However, the FCC selected the Columbia system anyway over NTSC. Preliminary transmissions were started using that system. One of the early broadcasts was an Army vs. (?) Navy football game. Various Pentagon brass got together to watch the game, and found that they could not see it with their B&W TV sets. This offended them into pressuring the FCC to reconsider their color standards choice. According to Webb, the way the pressure was applied by putting electric motors on a list of "essential strategic supplies" or some such. Since the Korean war was on, the Pentagon had some power to allocate strategic supplies, so they prohibited electric motors from being used in TV sets. I'd be very interested to know if anyone can confirm this last part of the story. It seems a little far-fetched to me but wierd things do happen in Washington. From uchinews!att-out!pacbell.com!sgiblab!zaphod.mps.ohio-state.edu!cs.utexas.edu!sun-barr!west.West.Sun.COM!grapevine.EBay.Sun.COM!sunicnc.France.Sun.COM!smckinty Tue Jan 12 10:25:38 CST 1993 Article: 33175 of alt.folklore.computers Path: uchinews!att-out!pacbell.com!sgiblab!zaphod.mps.ohio-state.edu!cs.utexas.edu!sun-barr!west.West.Sun.COM!grapevine.EBay.Sun.COM!sunicnc.France.Sun.COM!smckinty From: smckinty@sunicnc.France.Sun.COM (Steve McKinty - Sun ICNC) Newsgroups: alt.folklore.computers Subject: Re: What happened to "smart buildings"? and three tangents Date: 12 Jan 1993 11:06:28 GMT Organization: SunConnect Lines: 46 Sender: smckinty@France.Sun.COM (Steve McKinty - Sun ICNC) Distribution: alt Message-ID: <1iu8nkINN9l5@grapevine.EBay.Sun.COM> References: <184887@pyramid.pyramid.com> NNTP-Posting-Host: hardy.france.sun.com Status: R In article , Cannam@sc.ZIB-Berlin.de (Chris Cannam) writes: > > The idea is that in order to receive BBC TV, you need a TV licence. > (A cheap one for black-and-white TV, a more expensive one for colour. > The licence fee is the source of the BBC's income -- they don't have > advertising.) They claim that if you don't buy one, a TV detector van > will detect that you're receiving illicit TV and be around to your > house to take you away and throw you into a dank cell for several > years. Nobody quite understands (do they?) how the TV detector van is > supposed to work; the most common thesis I've heard is that it's all a > big con The vans do work. They rely on detecting the local oscillator radiation from the TV tuner, some of which escapes back up to the aerial and gets retransmitted. Its also very easy to detect the harmonics from the scanning circuits (try putting a medium-wave radio near a TV) but that can be confused with radiation from computer monitors. and really all they do is have the drivers look for TV aerials > on houses without licences. In whatever case, the vans certainly > exist, and they certainly do (occasionally) catch people. > > Perhaps more interesting are the arguments they get with people who > are thus nabbed, and then claim in court that they don't watch BBC -- > their TVs are only capable of receiving independent TV, or they only > use them with a video or computer, or whatever. Its not a valid argument. You require the license to have the TV, not to use it. Whether the law is right is a different issue, but 'I only watch coronation street' isn't a defence. In any case, the last figures I saw showed that the average household pays about twice as much per year to the Independent companies (by way of advertising costs incorporated in things they buy) compared to the BBC licence fee. You could make an argument that that is even more unfair because even people who haven't got a TV still pay the advertising costs. Steve -- Steve McKinty SUN Microsystems ICNC 38240 Meylan, France email: smckinty@france.sun.com BIX: smckinty From uchinews!daffy!uwvax!uwm.edu!cs.utexas.edu!zaphod.mps.ohio-state.edu!howland.reston.ans.net!europa.asd.contel.com!darwin.sura.net!haven.umd.edu!uunet!mcsun!uknet!edcastle!festival!ercm20 Tue Jan 12 14:33:49 CST 1993 Article: 33186 of alt.folklore.computers Path: uchinews!daffy!uwvax!uwm.edu!cs.utexas.edu!zaphod.mps.ohio-state.edu!howland.reston.ans.net!europa.asd.contel.com!darwin.sura.net!haven.umd.edu!uunet!mcsun!uknet!edcastle!festival!ercm20 From: ercm20@festival.ed.ac.uk (Sam Wilson) Newsgroups: alt.folklore.computers Subject: Re: What happened to "smart buildings"? and three tangents Message-ID: <30107@castle.ed.ac.uk> Date: 12 Jan 93 18:05:23 GMT References: Sender: nntpusr@castle.ed.ac.uk Distribution: alt Lines: 43 Status: R Cannam@sc.ZIB-Berlin.de (Chris Cannam) writes: > > In article <1iu8nkINN9l5@grapevine.EBay.Sun.COM> smckinty@sunicnc.France.Sun.COM (Steve McKinty - Sun ICNC) writes: > > In article , Cannam@sc.ZIB-Berlin.de (Chris Cannam) writes: > > > Perhaps more interesting are the arguments they get with people who > > are thus nabbed, and then claim in court that they don't watch BBC -- > > their TVs are only capable of receiving independent TV, or they only > > use them with a video or computer, or whatever. > > Its not a valid argument. You require the license to have the TV, not > to use it. Whether the law is right is a different issue, but 'I only > watch coronation street' isn't a defence. Strictly I believe you require a licence to operate at TV, not just to own it and not to receive TV broadcasts. (Despite what I think it says on the licence - I don't have one so I can't look it up! - a guy was successfully prosecuted some years back for owning a TV and using it exclusively as a computer monitor). There was also the case of a family who used to lock their TV away for 3 months of every 15 who confused the heck out of the licensing people's computer which wasn't set up to handle the licence lapsing and then being renewed after a short interval. No, I don't know the exact form of the confusion. > There was a case a few years ago in which some guy in Wales > demonstrated to the satisfaction of all concerned that he couldn't > actually receive BBC in his area, and hence won his case against > paying the fee. `I only watch Coronation Street' isn't a defence, but > `I can't watch East Enders even if I want to' can be. That's one I hadn't heard about. Some 12 or 15 years ago there was a celebrated situation in, I think, Broughton in the Scottish Borders, where the whole village was unable to receive BBC, only ITV. The villagers were understandably upset but were discouraged to find that the licence fee was for receiving TV broadcasts, not BBC broadcasts. I believe the BBC offered to build them a repeater for a little matter of about L1000 per household and that they refused. I don't know the current state. What's this doing in a.f.c?? Sam From slavins@entergrp.demon.co.uk Mon Aug 21 11:03:59 CDT 1995 Article: 111981 of alt.folklore.computers Xref: uchinews alt.folklore.computers:111981 Path: uchinews!vixen.cso.uiuc.edu!howland.reston.ans.net!tank.news.pipex.net!pipex!dispatch.news.demon.net!demon!user From: slavins@entergrp.demon.co.uk (Simon Slavin) Newsgroups: alt.folklore.computers Subject: Re: television monitoring Date: Mon, 21 Aug 1995 15:55:34 +0100 Organization: The Enterprise Group Ltd. Lines: 54 Distribution: world Message-ID: References: <414ub0$7hd@access1.digex.net> <4177vp$dn@axalotl.demon.co.uk> NNTP-Posting-Host: entergrp.demon.co.uk X-NNTP-Posting-Host: entergrp.demon.co.uk Status: R Okay, this should settle any discussion of UK TV Licensing rules. I hope all this is giving our foreign cousins a good laugh. I just spoke with a guy from the Licensing Policy Centre which is part of the TV Licencing Unit at Bristol. He said ... _Wireless & Telegraphy Act 1949_ (various amendments, especially _Broadcasting Act 1990_ which came into effect 1/4/91: a) If you have equipment capable of receiving any kind of picture signal, *including* Terrestrial, Cable, and Satellite broadcasts, you need a license. This includes VCRs with tuners, Satellite decoders, etc. i) minor exception ... equipment which can receive in-house broadcasts only (e.g. head-office sending satellite info to office in another country) needs no license. ii) there is some discussion over whether de-tuning all the channels on your TV renders it unable to receive broadcast transmissions. To be certain you won't be prosecuted, get the antenna socket disconnected from the tuner. Each case will be tried on its own merits. b) A license is awarded to a particular building and covers all the sets in use by a particular 'family' in that building (fuzzy definition). i) if one family has two homes (e.g. country-home, weekend-home) and one of them has a licence, and they won't be in use simultaneously then you can write and tell them and they'll write back with an exemption for the other home. ii) if the set has no fixed residence (e.g. is on a boat !) then you still need a license -- they'll register a pseudo-address on that license. iii) if the set is portable (wholly contains its power-source) and the you don't already have a licence for a building then you need a license for that set (as in part (ii) above). >From the above, I deduce that paying for a license is nothing to do with receiving BBC transmissions, even though the license money goes into BBC funds. The changes passed in the Broadcasting Act 1990 which re-defined the TV set meant that you need a license even if you're using your set only as a computer monitor *unless you get the tuner disabled*. I was given to understand that the number of people caught by detector vans was not much higher than the number of people who bought a TV set and then didn't get a license for the address they gave the shop. Simon. -- Simon Slavin - Computing Manager for The Enterprise Group Ltd. (Says my boss.) "Is all that we see or seem but a dream within a dream ?" E. A. Poe