HDTV resolution question, is this TV's res enough, what are other TV's res?

583 Views 3 Replies 4 Participants Last post by Erik Garci, Nov 8, 2001

Sizam

Discussion Starter · Nov 6, 2001

The direct-view HDTV I'm looking at has a max resolution of 1024 x 768, but "will display all HDTV signal at native resolutions" 720p/1080i. Is this a respectable HDTV resolution? I'll be buying this TV sight unseen since I can't find a dealer who carries one so I'd like to know what the resolutions are on some other TVs I've seen. What is the res on the 30" Loewe (WS), the 34" Sony (WS), the 32" Sony XBR, the Panasonic 34" (WS).

Thanks

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cwood

· #2 · Nov 6, 2001

Quote:

Originally posted by Sizam
The direct-view HDTV I'm looking at has a max resolution of 1024 x 768, but "will display all HDTV signal at native resolutions" 720p/1080i. Is this a respectable HDTV resolution? I'll be buying this TV sight unseen since I can't find a dealer who carries one so I'd like to know what the resolutions are on some other TVs I've seen. What is the res on the 30" Loewe (WS), the 34" Sony (WS), the 32" Sony XBR, the Panasonic 34" (WS).

Thanks

The resolution is bascially XGA and in about the same ballpark as all consumer type CRT direct view sets. Professional grade monitors cost thousands more for additional resolution and are limited in the amount of light output they can produce. Regardless, it is still occasionally possible to experience the "window" effect with a good consumer direct view CRT set.

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John Mason

· #3 · Nov 7, 2001

Welcome to the forums. What's really needed is an independent person or organization to test sets, as someone here recently requested . All the video magazines run charts showing color temperature but not measured resolution.

IMO, for the 1024 X 768 set, you'd be able to see much of the detail broadcast in many shows. To appreciate the details you could display, though, you'll have to sit close enough to resolve the detail. There are lots of threads here and elsewhere that go into viewing distance.

If you have a source for ABC, which usually transmits in the 720 X 1280P (Progressive) format (a few locations sideconvert to 1080 X 1920i [Interlace] format), such a set might almost deliver 'full' resolution.

Here's what an
experts committee (see 8/22 post) measured for actual resolution for these two HDTV formats:

Code:

Code:

[B]Measured resolutions of the ATSC 1080iX1920 HDTV system[/B]
           
Scan format         
1080 vertical lines
1920 horizontal pixels

                                                  Vertical     Horizontal          
Measured B&W Static Resolution                     800            1638
Measured B&W Dynamic Resolution                    400            1780^
Measured Color Static Resolution                   280            890
Measured Color Dynamic Resolution                  200            481


[B]Measured resolutions of the ATSC 720pX1280 HDTV system[/B]
           
Scan format         
720 vertical lines
1280 horizontal pixels
                                                   Vertical       Horizontal        
Measured B&W Static Resolution                     550            1139
Measured B&W Dynamic Resolution                    420            1068
Measured Color Static Resolution                   360            641
Measured Color Dynamic Resolution                  320            605

As you can see, for both the static B&W resolution (the figure usually provided) and the dynamic resolution for 720p, such a set nearly covers measured data from the experts.

For 1080I programming, it all depends. The experts measured 800 X 1638 static and 400 X 1780 dynamic (see note in the link about the 1780 figure). But these numbers assume that your 1080i source is delivering a full 1080i signal, which isn't always the case. An engineer for CBS outlined how they provide 1080i here (BobRoss's 8/10 post). And recently I tried an exercise (my 10/19 post) tracing a certain physical feature of tennis-star Anna Kournikova from CBS cameras through a 1024 X 768 plasma panel.

Problem is, a lot of supposed 1080i programs aren't broadcast at full resolution. Often the hardware used for production filters details beyond 1440 horizontal pixels. I took a stab here (my 6/9 post) at outlining this and other restrictions that may limit HDTV resolution. -- John

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Erik Garci

· #4 · Nov 8, 2001

Quote:

In this case I think that the phrase "max resolution of 1024 x 768" may refer to the maximum horizontal scanning rate to which the set can synchronize. The horizontal scanning rate of a video signal may be calculated by multiplying the number of total lines (which is greater than the number of visible lines) by the 60Hz vertical scanning rate (which is usually 60/1.001=59.94Hz to match NTSC).

Here is a list of some horizontal scanning rates.

480i: (525 / 2) * 60Hz = 15.75kHz

480p: 525 * 60Hz = 31.5kHz

1080i: (1125 / 2) * 60Hz = 33.75kHz

720p: 750 * 60Hz = 45.0kHz

768p: 806 * 60Hz = 48.36kHz

As you can see, the horizontal scanning rate of 768p (aka 1024x768) is higher than that of 1080i or 720p.

Even though the set displays these signals in their native format, the screen may not reveal all of the spatial resolution (or detail) that is contained within the video signal. One of the major factors is the dot pitch of a direct view set.

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