Old NTSC tricks: 240p?

Christian Corti cc at informatik.uni-stuttgart.de
Tue Mar 17 05:45:10 CDT 2015

On Mon, 16 Mar 2015, John Foust wrote:
> I'm trying to understand at a low level how some early computers
> and game consoles generated a non-standard form of NTSC.
> The Wikipedia http://en.wikipedia.org/wiki/Low-definition_television says:
> "Older video game consoles and home computers generated a nonstandard NTSC
> or PAL signal which sent a single field type which prevented fields from
> interlacing. This is equivalent to 240p and 288p respectively, and was
> used due to requiring less resources and producing a progressive
> and stable signal."

This has absolutely *nothing* to do with NTSC or PAL (or SECAM or 
whatever). NTSC etc. are colour encoding standards and don't describe in 
any way how a image signal is generated (fields, syncs, timing). They only 
describe how to put colour information into the signal.


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