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| PVT and HDTV etc |
Thu, 27 March 2003 20:06  |
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I saw a 42" Plasma screen HDTV on sale today with a digital computer connection too. I don't think you'd have much of a problem seeing a huge universe on that thing. Now if I only had an extra $4k....
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| Re: Screen resolution? |
Sat, 29 March 2003 00:55  |
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| BlueTurbit |
 | Lt. Commander
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BlueTurbit died Oct. 20, 2011 |
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| yucaf wrote on Fri, 28 March 2003 16:45 |
Is a HDTV good enough for use with computers? I know it's better than the normal TV thing, but is it THAT better? What is the definition of thoses beasties?
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HDTV is more than better than normal TV, it is MUCH better. It is much better than DVD when at 1080 mode.
High res HDTV 1080 is about 1920x1080. A low res 720p is 1280x720. However most HDTV don't have computer RGB 15 pin connector inputs. They do have svideo and composite video inputs but that's not quite digital quality. I believe many Plasma HDTV have these 15 pin inputs also.
BlueTurbit Country/RockReport message to a moderator
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| Re: Screen resolution? |
Sat, 29 March 2003 10:26 |
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Yep, thats why you get a special board for your computer, although I have seen, I think it was a Pioneer Elite, and that came with a computer connector.
Email me as ----jeffimix@----yahoo.com----
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| Re: Screen resolution? |
Mon, 31 March 2003 17:56 |
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| BlueTurbit |
| Lt. Commander
RIP
BlueTurbit died Oct. 20, 2011 |
Messages: 835
Registered: October 2002
Location: Heart of Texas | |
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| yucaf wrote on Mon, 31 March 2003 11:04 |
I had no idea it was such a high resolution  Where I live it's still reserved to very rich people, and I'm not in that category. I haven't cared to go to the only store that sells them.
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They are getting cheaper. As more are made the production costs go down each year. The first television cost as much as a car. The first VCR's were two to three times higher than TV's, about $800 and up. Now some VCR's even hi-fi 4-head go for as little as $59 and up in the USA. PAL systems are slightly higher because of higher resolution and also higher cost to make the higher quality circuits. PAL = Pay A Lot  Also SECAM, the French versions, are in that category. SECAM means System Essentially Contrary to American Method. The French like to do that. That is their chief purpose in life.
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However, there is a difference between the pure resolution (XXX x YYY) and how you see small letters on a TV screen, without blurring etc. TVs are not made to this use primarily so maybe they do not look so nice. Essentially, the higher resolution is intended to be able to make bigger screens that will sell more expensive... My point is: does anybody have seen a small letters computer text on a HDTV screen. Is it very good?
I would expect that the answer is yes, but I like to check things... 
YucaF
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Yes
The higher resolution is not intended just to make bigger but to make better. Projection TV's are already bigger using analog signals, but not better.
Resolution has to do with the number of lines and pixels per screen that the unit is capable of displaying. Standard TV for example, has a resolution of about 720x486 (slightly higher in PAL systems). That's 486 lines with 720 pixels per line. Comparable to a VGA 640x480 signal.
HDTV = High DefinitionTV = higher quality/resolution not bigger fuzzier letters. Fuzzier letters or objects are more related to analog (standard) TV's.
You are perhaps thinking of projection TV which is analog with a bigger screen. A PTV is an analog system
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| Re: Screen resolution? |
Tue, 01 April 2003 20:20 |
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Sorry to nitpick, but I don't want people getting the wrong info.
| BlueTurbit wrote on Tue, 01 April 2003 08:56 |
A PTV is an analog system that uses 3 CRT's (red, green, blue) that are small and use a high quality mirror and magnifier/focus lenses on each CRT to project the image onto the inside of a fresnel type screen.
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No. The classification of TV's as analog and digital depends on whether they can receive digital broadcast signals -- It is about what receiver they use, not what projection technology. There is nothing about a PTV that makes it analog. I have worked at a Philips Reaserch laboratory in the USA that has a lot to do with digital television and I have seen a digital PTV in action. I would like to tell you more about this TV (it is simply amazing) but I am under a non-disclosure agreement so I can't.
| BlueTurbit wrote on Tue, 01 April 2003 08:56 |
The fuzziness is due to the enlargement of inferior quality signal by comparison to digital signal.
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The fuzziness of a traditional PTV is due to the fact that the image is constructed before being passed through a series of lenses and mirrors. Imperfections in the the lenses and mirrors cause the signal to spread and become fuzzy.
| BlueTurbit wrote on Tue, 01 April 2003 08:56 |
A DVD signal looks much sharper and clearer than a broadcast signal on a larger PTV, for example. Yet DVD still has only 480 resolution.
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The DVD signal looks sharper because the analog signal being fed into the TV is sharper than the analog broadcast signal. This is because it has not had to travel through the airwaves.
Remember, all digital signals must be turned into analog signals before they are displayed. The advantage of a digital TV is that the signal is converted later in the stream.
| BlueTurbit wrote on Tue, 01 April 2003 08:56 |
The HDTV has 720 or 1080 resolution. That's 1080 lines with 1920 pixels per line. The quality of such a digital signal is very high.
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'The quality of the digital signal'? You can't actually transmit zeros and ones, you a
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| Re: Screen resolution? |
Wed, 02 April 2003 02:12 |
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| BlueTurbit |
| Lt. Commander
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BlueTurbit died Oct. 20, 2011 |
Messages: 835
Registered: October 2002
Location: Heart of Texas | |
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| Peptis wrote on Tue, 01 April 2003 19:20 |
Sorry to nitpick, but I don't want people getting the wrong info.
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Wrong info? Not really. I just tried to simplify it rather than use terms that a person who isn't a technician can understand better.
| BlueTurbit wrote on Tue, 01 April 2003 08:56 |
A PTV is an analog system that uses 3 CRT's (red, green, blue) that are small and use a high quality mirror and magnifier/focus lenses on each CRT to project the image onto the inside of a fresnel type screen.
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| Peptis wrote on Tue, 01 April 2003 19:20 |
No. The classification of TV's as analog and digital depends on whether they can receive digital broadcast signals -- It is about what receiver they use, not what projection technology. There is nothing about a PTV that makes it analog. I have worked at a Philips Reaserch laboratory in the USA that has a lot to do with digital television and I have seen a digital PTV in action. I would like to tell you more about this TV (it is simply amazing) but I am under a non-disclosure agreement so I can't.
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Oops! My boo. I should have said "standard" PTV. After all some HDTV are PTV also, but I am used to referring them to HDPTV's rather than PTV's. Rather than teach PTV theory I was trying to convey in more layman terms what causes fuzzy letters on a "standard" PTV. Which is primarily due to the often poorer reception analog signal that finally arrives at the CRT's and is blown up to larger size which also shows larger flaws. A scratch looks much worse under a magnifier than viewed with the naked eye. Remember I was comparing standard TV signal with HDTV not just analog vs digital here. But even a non HD digital signal will look better than an analog through the air signal at the CRT or picture screen end of path. As a DVD is a good example. A DVD has a higher quality picture than svideo and svideo is higher than composite and composite is higher than RF from an antenna or cable. These are all signals of different quality that do not pass through the air from one component to the next, yet there is a noticable difference in quality. The same can be said for VHS tape vs 8mm comparisons. But digital is the highest quality to date and High Definition is the highest digital quality in consumer TV electronics. Plasma is now the ultimate due to the elimination of the sub standard CRT projection processing thingy. 
| BlueTurbit wrote on Tue, 01 April 2003 08:56 |
The fuzziness is due to the enlargement of inferior quality signal by comparison to digital signal.
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| Peptis wrote on Tue, 01 April 2003 19:20 |
The fuzziness of a traditional PTV is due to the fact that the image is constructed before being passed through a series of lenses and mirrors. Imperfections in the the lenses and mirrors cause the signal to spread and become fuzzy.
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| BlueTurbit wrote on Tue, 01 April 2003 08:56 |
A DVD signal looks much sharper and clearer than a broadcast signal on a larger PTV, for example. Yet DVD still has only 480 resolution.
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| Peptis wrote on Tue, 01 April 2003 19:20 |
The DVD signal looks sharper because the analog signal being fed into the TV is sharper than the analog broadcast signal. This is because it has not had to travel through the airwaves.
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Again I was comparing resolutions. A DVD only uses a lower resolution by comparison to HDTV modes. I believe you verified what I said in that the analog signal picks up interference and noise which is amplified in the end compared with digital.
| Peptis wrote on Tue, 01 April 2003 19:20 |
Remember, all digital signals must be turned into analog signals before they are displayed. The advantage of a digital TV is that the signal is converted later in the stream.
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True. Except for plasma TV maybe? A composite of svideo doesn't have to go through the tuner circuits and be demodulated for example. Less circuits introduces less degradation. So a shorter route is better for any signal processing.
Again, we have to remember that the analog signal is amplified, so in the process of a weak and noisy signal being increased to a much larger size before getting to the final stage. A snowy picture will still look crappy at the CRT end as it did at the tuner end. Although there is much filtering and amplifying and processing throughout the journey from the front end to the rear end there is still a loss of quality in the process. A digital signal however, no matter how far away it is, as long as the 1's and 0,s can be detected will be duplicated or encoded as you prefer to say and will look just as sharp as if it had only traveled a couple feet through space. You CAN'T do that with analog signals. Believe me! I have never been in a Philips or Magnavox design lab, but I have spent thousands of hours in homes looking at the receiving end of signals via antenna, cable and satellites. I have spent many hours explaining to customers why they don't have a perfect picture. If I had told them "digital signals typically employ introduced redundancy in the form of error control coding" they would have shot me and I would not be telling my stories today. In Texas you don't say things like that to your customers. In fact if I were working in a lab and you said to me "do you know digital signals typically employ introduced redundancy in the form of error control coding?" I would say to you "Do you know I own a gun?" 
| BlueTurbit wrote on Tue, 01 April 2003 08:56 |
The HDTV has 720 or 1080 resolution. That's 1080 lines with 1920 pixels per line. The quality of such a digital signal is very high.
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| Peptis wrote on Tue, 01 April 2003 19:20 |
'The quality of the digital signal'? You can't actually transmit zeros and ones, you actually transmit an analog signal that is digitally encoded. Hence, the signal actually has the same 'quality'. The difference comes when you try to decode the signal. Digitally encoded signals are quantized, and hence small imperfections due to such things as thermal noise are eliminated. Furthermore, digital signals typically employ introduced redundancy in the form of error control coding. This means that occasional bit errors may be corrected, thus improving the reliability of the decoding process. This is why your CD will still play even though it is scratched.
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I was speaking of the quality of digital with respect to HDTV signals, 720 and 1080 TV resolution refers to HDTV signals does it not? Standard analog doesn't carry that resolution.
Actually you are transmitting a stream of data of 1's and 0's that is compressed MPEG2 in the USA (which is lossy compression or less than original quality, but still better than analog). And this is commonly referred to as digital signal in contrast to analog signal. To say that it is actually analog signal that is digitally coded only increases the confusion to the average person. Lets just say one is analog and the other is digital. Most people don't know about carriers and modulation and bandwidth, and thermal noise, etc. They just want to understand what digital is and why HDTV is better than the good old telly they've been watching since the crib.
| BlueTurbit wrote on Tue, 01 April 2003 08:56 |
Also the difference is analog signal vs digital signal. An analog signal is a small signal that is received by the TV and amplified. Along with the signal the noise and other signals are also amplified. Some attempt is made to clean them up, but a little distortion and negative attributes are always introduced into the final signal that goes to the CRT for viewing. Whereas a digital signal is not amplified, but duplicated or copied.
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| Peptis wrote on Tue, 01 April 2003 19:20 |
See above regarding the difference between analog and digital signals.
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In closing, I have spent thousands of hours in my lifetime servicing Philips, Magnavox, RCA, Hitachi, Mitsubishi, Sony, Zenith, Panasonic and a few other PTV's as well as many direct view models in the homes of consumers. I know picture quality. I have seen just about all models. I also know a lot about the inside of the different models and the quality as I am one guy who had to correct all the defects that the labs designed into these monsters. 
Knowing what I have seen on the other side of these creatures, I would not choose Philips or Zenith as one of my top three choices, for example. Sorry. My choices based on personal experience would be Mitsubishi or Hitachi or RCA, probably in that order with respect to overall quality and servicability. But everyone has an opinion.
[Updated on: Wed, 02 April 2003 02:25]
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| Re: Screen resolution? |
Wed, 02 April 2003 12:07 |
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| BlueTurbit |
| Lt. Commander
RIP
BlueTurbit died Oct. 20, 2011 |
Messages: 835
Registered: October 2002
Location: Heart of Texas | |
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| Peptis wrote on Wed, 02 April 2003 08:50 |
Thanks for your reply. You did clear up a lot of what you were saying, and I do agree with your clarifications.
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Thanks to you also for pointing out the fog. I did type in haste and didn't review the post I made very well. If I were to type it over I would make some changes. There are many engineers and such that have a better understanding of electronics than I do. As may be your case. I just rely on a lifetime of experience and theory/servicing classes with respect to consumer products from the servicing end. I know engineers that have told us they are amazed at what technicians are able to do on their hands and knees in the homes with respect to repairing these complicated systems. Whereas as a technician I also have been very impressed by many engineers and advanced technicians that I have spoken to on the telephone in the process of solving difficult problems via tech support systems.
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The purpose of my original post was that people don't get the wrong impression. Put it this way, if I got the wrong impression from your post then other people with less technical experience in the area could too.
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I'll buy that. I was trying to make it easier for lay persons to understand resolution on TV's in comparison to computer monitors and in the process of simplification made some unclear statements.
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I would also like to point out that I wasn't advertising Philips products as being any better than any other brand. In fact, I should have never even mentioned the name of the company. I don't even own a Philips set
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And I didn't mean to say Philips are inferior, nor is any other major brand. I don't own a PTV or HDTV either, nor a Mitsubishi. And most brands are good with respect to overall performance, including Philips. I have repaired the cheapest and the most expensive models. Just like cars, some sets never break down and some do. It doesn't matter much how much they cost or what brand they are. Although some models and brands appear to have more repe
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Re: Screen resolution?
Re: Screen resolution?
