Do CRTs Have A Native Resolution?

[no. 5]

I ask because in a thread today, a question was asked about an up-scaling DVD player and a CRT projection TV, and in the proses of formulating my response, I realized that I have a pretty incomplete knowledge of how a CRT display treats an incoming signal.

In every CRT TV screen that I've looked at, there appears to be discrete pixels, but I would assume that the electron beam could be steered and focused to the extent were one "pixel" on the screen could be used for more than one pixel of incoming video.

 

[avaserfi]

As far as my understanding goes CRTs "spray" an image at any given resolution to the back of a glass tube. This causes them to not had a native resolution which seems to be why they have less problems with showing SD material when they are an HD set compared to other sets.

 

[obscbyclouds]

AFAIK, CRT's do not have a "native" resolution in the way fixed panel displays (like Plasma and LCD's)do. They are a strictly analog device. One of the key elements with CRT's from my understanding is the dot pitch, or size of the dots energized by the electron beam from the guns (in the case of RP CRT's or Front Projection CRT's there is a red, blue and green gun). Another is the focus, and speed of the electron beam. This is why CRT's require more calibraion that fixed pixel displays to have that crisp, clear image.

With all that being said, my Oppo still looks better upscaling to 1080i than it does set to 480p, and SD still looks like crap....

 

[mrtriggerfinger]

Plasma resolution

I want to run a slide show on a 65" Plasma from a MacBook Pro at an exhibition.

Do I create the slideshow at 72dpi like any other computer resolution or does it need to be set up differently?

Thanks

 

[no. 5]

Thanks, thats pretty much what I thought, but as CRTs aren't 'sexy' anymore, the technical aspects are not as widely available as they are for LCD, so I wanted (want?) some more impute.

So, I would imagine than, that an up-scaling DVD player would be of more use to a CRT owner than a Plasma, or LCD owner (if the display could accept HD)?

I want to run a slide show on a 65" Plasma from a MacBook Pro at an exhibition.

Do I create the slideshow at 72dpi like any other computer resolution or does it need to be set up differently?

Thanks

I would look up the Plasma's specs to see what resolutions the display will accept. You may need to look up how to convert 'computer resolution speak' to 'consumer video resolution speak', as you are going to run into specs like 720p, 480i, ect... ect...

 

[obscbyclouds]

So, I would imagine than, that an up-scaling DVD player would be of more use to a CRT owner than a Plasma, or LCD owner (if the display could accept HD)?

I believe that it's considered to be the other way around, as CRT's can display multiple resolutions well, whereas you want an upscaling DVD player for LCD's and Plasma so the input signal is the native resolution of the display. However, all that probably depends more on the scaler quality of your display vs. the scaler of the DVD player. In my case, the Oppo does a better job of this than my TV.

I still say that my CRT has a better picture quality than many LCD's and Plasma's that I've seen. But you're right that they aren't "sexy" anymore, which is kind of a shame if you ask me, as it's a proven technology, lasts a really long time, and still provides the best black levels (contrast ratios in the 1,000,000:1 range) of any technology avaliable currently. This may change with LED based microdisplays, but I haven't seen reason enough to throw mine away yet

 

[no. 5]

I believe that it's considered to be the other way around, as CRT's can display multiple resolutions well, whereas you want an upscaling DVD player for LCD's and Plasma so the input signal is the native resolution of the display. However, all that probably depends more on the scaler quality of your display vs. the scaler of the DVD player. In my case, the Oppo does a better job of this than my TV.

What I was thinking was if a person wanted a DVD to be in "high-def", since a LCD or Plasma is already upscaling the 480 of a DVD to the displays native resolution, an upscaling player could very well be pointless (depending, as you said, on the quality of the scaler in the TV), but if a CRT displays 480 as 480 and 720 as 720, they would need the player to scale to 720 or 1080... at least, that's my theory.

 

[mtrycrafts]

Thanks, thats pretty much what I thought, but as CRTs aren't 'sexy' anymore, the technical aspects are not as widely available as they are for LCD, so I wanted (want?) some more impute.
So, I would imagine than, that an up-scaling DVD player would be of more use to a CRT owner than a Plasma, or LCD owner (if the display could accept HD)?

Here you go. Electron beams, continuously scans the screen to form a frame. NTSC is interlaced TV so every other lines are scanned at 1/60sec then the next 1/60 sec, the missing lines, even in one field, odd in the next. There is no dot pitch to it. The beam is focused so it scans the appropriate number of lines that it was designed to do. Its IF tuner section determines its resolution horizontally and the design number for the vertical, 525 in standard TV with not all visible lines as some are used for sync and other purposes.

If a CRT is designed for higher than 525 interlace, like line doubling, then the scan rate must be designed into its capability.

So, in essence, a CRTs does have a max native resolution designed into it with fixed scan lines, unless it is designed for higher scan rates for the 720p type uses.

 

[sholling]

My understanding is that yes they do. In the case of the CRT HD ready TVs that I've owned that resolution is 1080i. According to the manual of my first one the TV upscales lower resolution signals to fit the 1080i format, however the clarity is no better. Basically in simple terms it's just using multiple pixels to emulate a single pixel.

I agree that CRTs aren't sexy but the picture rocks. Ultra fast response and very fine pixels. If it weren't for burn in issues that would be hard to beat.

 

[obscbyclouds]

There is no dot pitch to it.

This is a quote from the audioholics display technology guide:

"A cathode ray tube (CRT) is a specialized vacuum tube in which images are produced when a moving electron beam strikes a phosphorescent surface. There are three factors that limit the resolution on CRT display devices: screen dot pitch, electron beam size, and the bandwidth of the video amplifier. A typical CRT has a dot pitch around 0.8 - 0.9mm (much larger than a typical computer display). Lowering the dot pitch increases the display resolution, but increased dot pitch provides a brighter picture. Most CRT displays are configured to perform well with lots of ambient light, so dot pitch is typically higher."

I'm a bit confused, is this just referring to direct view CRT's?

 

[mtrycrafts]

This is a quote from the audioholics display technology guide:

"A cathode ray tube (CRT) is a specialized vacuum tube in which images are produced when a moving electron beam strikes a phosphorescent surface. There are three factors that limit the resolution on CRT display devices: screen dot pitch, electron beam size, and the bandwidth of the video amplifier. A typical CRT has a dot pitch around 0.8 - 0.9mm (much larger than a typical computer display). Lowering the dot pitch increases the display resolution, but increased dot pitch provides a brighter picture. Most CRT displays are configured to perform well with lots of ambient light, so dot pitch is typically higher."

I'm a bit confused, is this just referring to direct view CRT's?

Read more on this here:

http://en.wikipedia.org/wiki/Cathode_ray_tube

CRTs have shadow masks, fixed in size based on scanning lines and the max video amp bandwidth that gives horizontal resolution. You make the so called dot resolution smaller will not increase resolution unless you change the video amp capability.
I guess some will call the mask slots their 'fixed dot pitch.' In that sense it is fixed. And certainly I didn't mean to imply in my post that you can vary it in a given TV CRT. The size is established by the standards it is supposed to accommodate.

 

[Duffinator]

My understanding is that yes they do. In the case of the CRT HD ready TVs that I've owned that resolution is 1080i. According to the manual of my first one the TV upscales lower resolution signals to fit the 1080i format, however the clarity is no better. Basically in simple terms it's just using multiple pixels to emulate a single pixel.

I agree that CRTs aren't sexy but the picture rocks. Ultra fast response and very fine pixels. If it weren't for burn in issues that would be hard to beat.

I agree with this, my Toshiba 56H80 from 2000 does this. So while not being a fixed pixel display like a plasma or LCD it does display a consistent resolution regardless of input. In other words everything is scaled to 1080i. But CRT's have the flexibility to display several resolutions where fixed pixel displays don't.

While I agree that CRT's can look amazing, more film like to my eye, I prefer the look of a good plasma and LCD for two reasons. The pictures have brighter colors without washing out the picture and tend to be sharper (not smoother) especially when compared to RPTV's that inherintely have convergence issues.

 

[Joe Schmoe]

CRTs aren't 'sexy' anymore

That is true, and it is also a real shame. The new technologies allow larger screen sizes, but I have yet to see any that can equal the picture quality of my direct-view tube.

 

[Duffinator]

That is true, and it is also a real shame. The new technologies allow larger screen sizes, but I have yet to see any that can equal the picture quality of my direct-view tube.

But there's the problem, who wants to watch a puny 34" screen? Not me.

 

[Joe Schmoe]

But there's the problem, who wants to watch a puny 34" screen? Not me.

Someday, the technology will exist to make a big screen with the same or better PQ. Until then, I am quite happy with my "puny" 34" screen. (especially as it seems huge compared to the 27" 4:3 screen I had been watching before I bought it.)

 

[Duffinator]

How quickly a 34" went from big to small. Check out a 100"+ projection screen sometime for some real fun.

 

[Buckeye_Nut]

Someday, the technology will exist to make a big screen with the same or better PQ. Until then, I am quite happy with my "puny" 34" screen.

You need to upgrade to High definition

 

[Joe Schmoe]

You need to upgrade to High definition

My CRT is high definition.

 

[j_garcia]

I use a 34" CRT also. Havent' seen an comparably priced LCD or Plasma that looks as good.

 

[obscbyclouds]

I'll throw my name in as one who still hasn't seen a Plasma or LCD that's wowed me enough to throw away my 5 year old CRT. A Pioneer Elite Plasma is probably the closest, but also $3,000!

Everyone is so worried about convergence, takes me 30 mins every 6 months or so to adjust to convergence in the Service Menu......and I probably don't need to do it that much, but I'm one of those guys