Quantcast

Samsung CRT-HDTV!

Nick_UK

Banned
An excellent description Stephen :smashin:

It's easy to spot those who gained their knowledge from years of practical experience, and those who merely repeat stuff they have read from text books and dubious articles on the internet.
 

Welwynnick

Well-known Member
Nick_UK said:
An excellent description Stephen :smashin:
Absolutely. I have long thought Stephen to be the most authoritative contributor to this forum. Those posts ought to go in a sticky.

Do you remember, though, who was the only other person who was questioning the scanning method of plasmas, who said: "I'm not clear on how the sub-field pixels are illuminated. There is obviously a scanning process, as the system is still matrix based." and: "I would be interested to know exactly how the pixels are addressed and "fired", and also how the sub-fields operate."

I don't think anyone on the forum really knows the answer. It would be very good to find that out from someone who does.

Nick :confused:
 

Nick_UK

Banned
This seems to be the best "simple" description. Of course, any display with X and Y addressing is going to end up being addressed in a sequence which emulates CRT scanning. However, the big feature of neon discharge tubes which you are overlooking is that a neon discharge tube remains lit after being "struck" as long as a lower sustaining voltage is maintained. So the information to tell the pixel to light up or stay un-lit is passed to the pixel using a technique similar to scanning, but (unlike the CRT), pixels remain lit after being energised. You then apply PCM encoding to change the brightness of the pixels. It's explained very clearly in the article.
 

Stephen Neal

Well-known Member
Nick_UK said:
This seems to be the best "simple" description. Of course, any display with X and Y addressing is going to end up being addressed in a sequence which emulates CRT scanning. However, the big feature of neon discharge tubes which you are overlooking is that a neon discharge tube remains lit after being "struck" as long as a lower sustaining voltage is maintained. So the information to tell the pixel to light up or stay un-lit is passed to the pixel using a technique similar to scanning, but (unlike the CRT), pixels remain lit after being energised. You then apply PCM encoding to change the brightness of the pixels. It's explained very clearly in the article.
Will read that when I get a chance. The interesting feature of some frame-store based matrix displays is that you can split the display into smaller panels, and address/refresh them separately and simultaneously - whereas with conventional CRTs there is only a single/triple flying spot so you only scan/address one bit of the screen area (or the three phosphor dots) at a time.

This forum is great for kicking round ideas with other curious minds - none of us come close to knowing everything about anything - but it is always useful to share what we do know, or what our informed speculation on a subject is. I've certainly had some mistaken assumptions (often long-held) corrected politely by others - long may it continue.
 

cerebros

Active Member
welwynnick said:
Bang on.
But the frequencies are a bit higher than that because of the lines that are broadcast or stored, but not displayed - teletext, frame sync, etc.
yeah but i couldn't recall the figures off-hand and even the ones i gave give an idea of the differences involved (I also actually posted several minutes before you but it seems to have taken an age to upload to the site for some reason - I wouldn't have bothered posting if your post had been there when I came back to this thread)
 
Top Bottom