Re: C64/128 vs Apple -- Video?

["Bryan Parkoff" <nospam@nospam.com>]

"Linards Ticmanis" <ticmanis@gmx.de> wrote in message 
news:44a05174$0$26254$9b4e6d93@newsread2.arcor-online.net...
> Bryan Parkoff wrote:
>
>>     Now, what about C64/128?  It has 40x25 lines so it looks like 640x200
>> resolution.  Do C64/C128 use CGA font?  Is video circuit more complex, 
>> but
>> Apple II's video circuit is little simpler?  I am curious.
>
>
> Commodore doesn't use artifact color. Their circuit creates the chroma
> signal independently of the luma. So they are not bound to a n�3.58 MHz
> pixel clock. In Commodores, there are 7 (NTSC) or 9 (PAL) chroma cycles
> per 8 luma cycles.
>
> Also this makes it easy to use almost the same circuit and still be
> fairly compatible in software for NTSC and PAL.
>
> The Euroapple uses a very indirect method of PAL color creation: It
> reads and interprets the NTSC output signal of the normal circuits, then
> duplicates it in PAL. The European Commodores create PAL directly.
>
> -- 
> Linards Ticmanis
Linards,

    Are you saying that C64 uses color reference in 7 MHz rather than 3.58 
Mhz?  I know that all NTSC and TV are capable to use 3.58MHz for all TV 
channels.  No matter how high frequency is, but it still uses artifact 
colors.  How can color reference in 7 MHz be done?  What is the difference 
between regular color and artifact color.  For example, Apple II uses Deep 
Red which it is two pixels out of four pixels plus black gap.  Do color 
reference in 7 MHz fill Deep Red in four pixels?
    I hope that Michael Mahon will explain more how it is done to overcome 
color artifact.

Bryan Parkoff