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Old 26th Jun 2010, 10:01 am   #9
Parabola
Retired Dormant Member
 
Join Date: Sep 2008
Location: London, UK.
Posts: 117
Default Re: Test Card / Teletext Generator - Phase 1

Quote:
Originally Posted by ppppenguin View Post
What you really want is a small CPLD.
I knew you'd say that! I know you find my adhesion to TTL/CMOS unfathomable

Quote:
Originally Posted by ppppenguin View Post
Should be possible to get a Xilinx Coolrunner evaluation kit quite cheaply.
But then I'd have to learn how to program it, and I'm monumentally lazy. I also think that would make any future 'production' cost more. At the moment, all the bits I've used really are bargain basement.

Quote:
Originally Posted by ppppenguin View Post
Alternatively in CMOS etc the only sensible way to do it is with '163 chips.
Nah! On this one I'm going to dare to fail to concur with your assertion! There was a reason I ruled out '163s at an early stage.

Quote:
Originally Posted by ppppenguin View Post
I think RR used 12MHz because it allowed a convenient size PROM and ran a speed that was friendly to the PROM. It's pretty marginal for full bandwidth TV. 13.5MHz is the international standard for SDTV.
I know what you're saying, but I reasoned that 720 pixels at 625 was fine for a still image. All the resolution bars are produced correctly. I could push it up to 13.5 (may need 55ns PROMs) if you think it would add a certain something I've overlooked

Parabola
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