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Flat panel LCDs and global warming

m32825 on Fri July 04, 2008 11:09 PM User is offline

Check this out, "HD TV gas 17,000 times worse for planet than CO2":

http://www.reghardware.co.uk/2008/07/03/nitrogen_trifluoride_tv/

NickD on Sat July 05, 2008 5:55 AM User is offline

We all breathe nitrogen, 80% of the air we breathe is nitrogen, but fluorine is one of the most active elements in the periodic table and because it is so active, can combine and damage human and plant tissue. It's combined with nitrogen (NF3) to make it a bit safer to handle but in the actual process of etching silicon, is broken down again into it's separated into nitrogen and fluorine where the nitrogen doesn't do much of anything, but it's the fluorine that does all the work. Very similar to chlorine another highly active element that is not found in nature, both hang unto anything they can find to form more harmless compounds.

So here we go again, with looking at just one small part of the picture, NF3 like fluorocarbons are not chemically stable in that they are broken down back to their basic elements with UV radiation, where their active elements found in nature are returned to their natural state. No, I would not want to stick my head into a bucket of either fluorine or chlorine, but these are also two elements we cannot live without and when used in manufacturing, their confinement must be very tightly controlled. One way to ease the control of these elements is to have their use in countries where they are more interested in their economy than the health of their workers and where liability laws do not exists.

There are advantages to digital transmission since the detection of low level signals is determining the strength of logical one's and zero's is that same as the high level signals for a superior signal to noise ratio and since the data can be sent in packets, the bandwidth is much lower than the old NTSC system where a mere 95 channels consumes a bandwidth from 50 MHz to over a one GHz. But for overall quality, the LCD or plasma screens leave a lot to be desired especially when viewing photos compared to my old fashion Viewsonic 21" monitor. But I would rather carry an LCD than that Viewsonic any day of the week.

With wall protectors, we compared my old Panasonic three CRT projector with my son's new Panasonic LCD projector, like 120 VAC motors that output a zillion horsepower, the CRT rated at drastically lower lumen output, has over twice the brightness of the LCD. And that LCD has a very expensive high wattage light bulb to replace with a life of maybe 1,000 hours, where the CRT's have a known lifespan of over 20,000 hours. Power input is about the same. His projector weighs about ten pounds, my old one about 120 pounds. His projector is very easy to set up where I can spend hours converging mine. But if done correctly, his picture quality is far worse than mine.

I have already seen HDTV to NTSC converters on the shelves for under 50 bucks, but yet another remote, and a box, and even more cables!

Seems like our congress should be more interested in the honesty of what we watch rather than the technical aspects of television and that honesty should begin with them.

Karl Hofmann on Sat July 05, 2008 10:18 AM User is offlineView users profile

As you said, Nick it is all well and good having a fancy TV but if the stuff that they put on it is crap, then where is the point. In the Winter I may watch 4 hours of TV a week, and that is about all that is any good

-------------------------
Never knock on deaths door... Ring the doorbell and run away, death really hates that!

Matt L on Tue August 05, 2008 2:33 PM User is offline

I recently purchased a new LCD set, which supports 720p. There's no need to get 1080p unless you want to watch Blue-Ray disks, since there is no current broadcast at 1080p. By the time that the broadcasters go "Full HD," the prices will come down and I'll get another, probably paying less total for two sets than buying one 1080 set today.

But you're right, the problem is the content. There are some old movies being remastered in HD, and these are sometimes fun to watch. Also some series, but that's not nearly as important to me. Movie makers often try to make a scene actually look good and put time into it. TV series just chuck them out week after week with little regard to anything scenery other than trashy eye candy.

However, lest you think that I don't really appreciate the set, I have one word for you: Football. Specifically NFL games broadcast in HD. Actually there's another word: Hockey, with the NHL.

Watching football and hockey games in HD can't be beat. There is a little distortion due to the compression, but I can live with it. The clarity, especially of static images, is great. You can actually read the players' names and numbers when they're in the background.

NickD on Wed August 06, 2008 6:58 AM User is offline

With my now 20 year projector, with NTSC, really not that bad either and watch a 10 foot diagonal screen, vertical resolution with a interlacing circuit is producing an effective 1050 lines and the 4.5 MHZ bandwidth produces an effective 600 pixels. But there are other factors in producing a viewable picture like contrast ratio, it's infinite with analog, LCD cannot produce that wide range. And just like these 6.5 peak HP motors we are seeing today, the response time of LCD's is much slower and rather than considering that important factor, they are just counting pixels without stating you are not getting that much, because each pixel cannot respond that quick to show a viewable change. More in the BS arena than pure fact. But if you are comparing an LCD with a consumer quality TV set, you have a valid argument, these are crap, but what can you expect for 150 bucks?

The nasty thing about NTSC is it is bandwidth hungry and one of the major reasons for going digital, on NTSC you see a totally new frame every 33 milliseconds, with digital, just get an update on what changed from the last frame, that alone saves a ton of bandwidth. The old VHF/UHF just about consumed the entire available frequency spectrum with a 95 channel limit, with digital, can get a thousand channels in one tenth of that bandwidth. So we are offered a much wider choice of crap to watch.

Another advantage of LCD is like comparing a CFL bulb to an incandescent bulb more lumen output with lower energy input, it will cost us far less in energy to get bored in front of the box and you can hang your TV on the wall like a picture, but the quality of the picture, I am not just seeing it.

Ha, with the woman's touch, wife did make me buy a nice looking coffee table to replace the old milk carton containers I had that 130 monster sitting on, but in terms of replacing that back breaker, she is letting me keep it, because we looked at the latest alternatives, just not seeing the picture quality. So when she brings friends over, she says our TV viewing room is my room and you know how husbands are. I do have a ceiling mounting kit, but don't like the idea of standing on a ladder to converge it, another PITA. Ha, and even sure the ceiling is strong enough to support it.

Ah, football, with Bret wanting to come back, forget about the war in Iraq, the election, that is all that is on the news now. Bret and Thompson do not get along, always a debate on which players to get. Seems to me the QB has far superior knowledge of the game than some dingbat GM, but sure points out the politics in sports, I quit watching football about 8 years ago, no skin off my nose who wins or loses. When the Cubs swept the Brewers, four Brewer fans pounded the crap out of a Cub fan. Reminds me of my high school days when I was brainwashed that our greatest enemy was a town five miles up the road, the whole thing is stupid. Half the fans are happy, the other half, it's the end of the world, still have to get up the next morning for your miserable job and not making 20 million or more a year.

Ha, didn't know my wife is quite the soccer fan and it's more fun for me to watch how excited she gets than watching the actual game. But some remarkable facts about this game, ESPN actually shows a full 45 minutes of it without a commercial break! Football has a commercial break every 15 seconds. But don't they have any plays in soccer? Just a bunch of guys randomly kicking a ball back and forth trying for an accident to hit the goal.

Matt L on Wed August 06, 2008 12:16 PM User is offline

You make some good points, but you did make an error in saying that the contrast ratio of analog is infinite. While this is (effectively) true of the end-stage hardware (your CRTs), it is not true of the signal itself.

The signal-to-noise ratio limits the effective bandwidth, which limits the real contrast ratio. And note that you don't have 4.5Mhz bandwidth. That's for the entire feed, including the 3.5xx Mhz color subcarrier (and the audio subcarrier, but that is higher). That subcarrier limits you to 3.5xx Mhz of luminance bandwidth. If luminance encroaches on this limit, you will see color artifacts in the picture.

Shannon and Weaver came up with the relationship between information content (they call it "entropy") and the combination of bandwidth and signal/noise ratio. It's some interesting stuff, if you like mathematical information theory. It was written in the late forties, and describes the problems that modem designers would face decades later (plus this sort of thing).

NickD on Wed August 06, 2008 4:39 PM User is offline

The SN ratio is arbitrary depended upon the source, best I have seen is from this outdated 12" laser disk player, the picture was so sharp and clear had to be careful you didn't touch the screen, could cut your finger. Did work for Zenith back in the 60's designing IF amplifiers if that counts for anything, not very long, way too structured for my taste and I preferred to design entire systems and with Zenith, had to use more components for the interface between sections that seemed to be a waste.

NTSC video bandwidth is 4.5 MHz, the 3.58 MHz color subcarrier is suppressed in transmission therefore it's sidebands containing the color information cannot be demodulated by the Y video detector so the video is not cutoff like you say it is. The bandwidth of the carrier reinserted two color components, one is 500 KHz, the other I believe is around 1 MHz, but these are fill in signals. The channel bandwidth is 6 MHz that really hogs up the available frequency spectrum, but NTSC is quite the system, color subcarrier system was designed in 1954, really quite remarkable as were other systems designed in the USA when this country was the leader in the field of electronics, that is disheartening.

LCD's should be dirt cheap, like printing a newspaper, but if one section line is printed too lightly, you will see a black square on your screen if that line erodes away, and they do.

Matt L on Wed August 06, 2008 5:04 PM User is offline

I think we agree that the price of LCD screens will come down, simply due to the demand that will be present in the future. They are too expensive now, but yet I did buy one.

What is amazing is the apparent dirt-cheap price of a new CRT tube. These would seem to take some serious time and resources to produce. But I suppose the tooling is basically free.

I remember back in my high-school days working at a TV repair shop, replacing a few CRT tubes. Back then, it was easily a $400 job for a 25" console set. The set cost about $1000 back then - that's about a quarter to a third of a Chevy Nova to put it in perspective for the younger crowd.

I wasn't aware that the sidebands would not affect the main carrier. It seems as they would do so during the IF mixing. I realize that you don't even need to transmit the main carrier as the sideband contains (nearly) all of the information present. But doesn't mixing in the IF stage cause the sidebands to affect the main carrier? Perhaps not; there is some apparent magic going on, given the quality that you can get from a decent, modern NTSC set with a good source.

NickD on Thu August 07, 2008 9:43 AM User is offline

Yes, those were the good old days, even twenty years ago, we had five TV repair shops in town, today we have zero and with the ridiculous price on repair parts, don't even bother repairing them myself. Ha, remove the CRT, smash the case with a sledge hammer, was taking off some reusable parts, but don't even do that anymore. Put the remains in a plastic bag and set it out with the rest of my garbage so I don't have to pay a 30 buck recycling fee.

Figure it's not my fault nor responsibility that with our government laws are such that we can only buy garbage, so why should I have to pay additionally to get rid of it? This stupid government was paying the Japs 10% for all the crap we were importing from them, try and compete with that! And our EPA kicked out all of our component manufacturers.

When the buck was finally devaluated against the yen, we could finally compete with them, so what do they do, bring in the Chinese.

200 bucks for a cell phone that dies with two drops of water on it, that costs only eight bucks to make, never in the history of this country have consumers owned more electronic stuff, all crap overflowing the landfills. And can't even buy lead solder anymore.

What happened that Sony can own our entertainment industry? Use to be a law against this, exactly who are our representatives working for? Sure in the hell, not us.

Edited: Thu August 07, 2008 at 9:46 AM by NickD

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