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In article <1992Nov12.190043.1@mars.slu.edu> jesse@mars.slu.edu writes:

>What is the resolution of normal NTSC TVs?

   NTSC is an analog format with a total of 525 lines.  However only 485 lines 
are active.  The most universal is about 648x485 pixels; and NTSC cycles at 
approximately 59.94Hz.
 


-- 
Jonathan Heiliger ........ Electric Power Research Institute
Internet: -/- jonathan@rahul.net -/- flix@mecca.epri.com -/-
Telephone <*> (415) 855-2888

In article <Bxn4Jt.K2p@rahul.net>, jonathan@rahul.net (Jonathan Heiliger) writes:
> In article <1992Nov12.190043.1@mars.slu.edu> jesse@mars.slu.edu writes:
>
>>What is the resolution of normal NTSC TVs?
>
>    NTSC is an analog format with a total of 525 lines.  However only 485 lines
> are active.  The most universal is about 648x485 pixels;

Most video digitizers I've come across seem to prefer to give you 640*480
resolution when grabbing frames from an NTSC source. I guess they're just
rounding it to a more convenient number. Or perhaps there's some standard
allowance in there for overscan.

> and NTSC cycles at approximately 59.94Hz.

I heard that the original black-and-white NTSC was 60Hz, and that the frame
rate was lowered slightly to accommodate the colour signal--probably a question
of avoiding interference between integer multiples of different frequencies.

Lawrence D'Oliveiro                       fone: +64-7-856-2889
Computer Services Dept                     fax: +64-7-838-4066
University of Waikato            electric mail: ldo@waikato.ac.nz
Hamilton, New Zealand    37^ 47' 26" S, 175^ 19' 7" E, GMT+13:00

In article <1992Nov17.113157.12225@waikato.ac.nz> ldo@waikato.ac.nz (Lawrence 
D'Oliveiro, Waikato University) writes:

>I heard that the original black-and-white NTSC was 60Hz, and that the frame
>rate was lowered slightly to accommodate the colour signal--probably a 
question
>of avoiding interference between integer multiples of different frequencies.

  I couldn't tell you exactly.  I was told and I have seen in print that NTSC 
cycles at 59.94Hz.  A 60Hz reading could just be a 'round-up'
 
-- 
Jonathan Heiliger ........ Electric Power Research Institute
Internet: -/- jonathan@rahul.net -/- flix@mecca.epri.com -/-
Telephone <*> (415) 855-2888

In article <D559TB2w165w@tsoft.sf-bay.org> bbs.peter@tsoft.sf-bay.org (Peter Blum) writes:
>NTSC was the first Television 
>format and it is the worst in comparason to PAL and SECAM, but HDTV is on 
>the way.

Can you tell us a little bit about HDTV and when it is expected to
arrive?

-- 
Marshall Lake
...!uunet!{media,mimsy!bogart}!irscscm!mlake
mlake@irscscm.UUCP

In article <1992Nov17.113157.12225@waikato.ac.nz>, ldo@waikato.ac.nz (Lawrence D'Oliveiro, Waikato University) writes:
> In article <Bxn4Jt.K2p@rahul.net>, jonathan@rahul.net (Jonathan Heiliger) writes:
>> In article <1992Nov12.190043.1@mars.slu.edu> jesse@mars.slu.edu writes:
>>
>>>What is the resolution of normal NTSC TVs?
>>
>>    NTSC is an analog format with a total of 525 lines.  However only 485 lines
>> are active.  The most universal is about 648x485 pixels;
> 
> Most video digitizers I've come across seem to prefer to give you 640*480
> resolution when grabbing frames from an NTSC source. I guess they're just
> rounding it to a more convenient number. Or perhaps there's some standard
> allowance in there for overscan.
> 
>> and NTSC cycles at approximately 59.94Hz.
> 
> I heard that the original black-and-white NTSC was 60Hz, and that the frame
> rate was lowered slightly to accommodate the colour signal--probably a question
> of avoiding interference between integer multiples of different frequencies.
> 
> Lawrence D'Oliveiro                       fone: +64-7-856-2889
> Computer Services Dept                     fax: +64-7-838-4066
> University of Waikato            electric mail: ldo@waikato.ac.nz
> Hamilton, New Zealand    37^ 47' 26" S, 175^ 19' 7" E, GMT+13:00
Truevision with their TARGA series pretty much set a defact frame grabber
standard early on. 512x480 is full screen and there is a lessor mode for a 
black box around the video. Even 512x480 offers more than NTSC resolution when
the capture is in 24bit colour.

Don
djlewis@ualr.edu

In article <1992Nov17.171855.1@ualr.edu>, djlewis@ualr.edu writes:

|> Truevision with their TARGA series pretty much set a defact frame grabber
|> standard early on. 512x480 is full screen and there is a lessor mode for a 
|> black box around the video. Even 512x480 offers more than NTSC resolution when
|> the capture is in 24bit colour.
|> 
|> Don
|> djlewis@ualr.edu
|> 

So, if I understand you correctly, you contend that grabbing an
NTSC signal on a 512x480 x 24-bit frame grabber "offers more than
NTSC resolution". 

How is it possible to increase the resolution of a given signal
simply by digitizing it at 24-bits (and at less than the commonly
accepted 640 x 480 resolution, at that)?

Greg Estes

In article <1992Nov17.145013.18836@irscscm.UUCP> mlake@irscscm.UUCP (Marshall 
Lake) writes:

>Can you tell us a little bit about HDTV and when it is expected to
>arrive?

   Some people will say it has already arrived.  But there is no 'approved' 
standard.  Both Sony & Panasonic already have some HDTV gear available.  
However currently there are already two different standards.  One is SMPTE, 
which is a digital signal, with 1920 pixels by 1035 lines at a 16/9 aspect 
ratio (what you see in movie theaters/widescreen) cycling at 60Hz.  The other 
is Eureka, which is 1920 pixels by 1152 lines at a 16/9 aspect ratio, cycling 
at 50Hz.
 


 
-- 
Jonathan Heiliger ........ Electric Power Research Institute
Internet: -/- jonathan@rahul.net -/- flix@mecca.epri.com -/-
Telephone <*> (415) 855-2888