Michael J. Mahon wrote:
In the personal computing world of the early 1980s, there were two
video "camps": those who used the artifact color trick and those
who didn't. One glance at the master clock frequency was usually
enough to tell the difference. ;-)
Hmmm... Commodores use a 14.31818 MHz main quartz too (the NTSC
versions, that is). Their pixel clock is quartz frequency divided by 7,
then multiplied by 4.
But did they also use the 14MHz clock divided by 4 for the chroma
subcarrier frequency? In that case, they just saved having to add
a 3.58MHz crystal for the chroma modulator. I suppose that saved
a fraction of a dollar.
Yes, that's the case. And we all know how cheap they were... ;-)
Though deriving everything from a single quartz probably also cuts down
on Moir� effects, of the kind that plague the PAL Apples.
In fact they used 17.733475 MHz crystals in their PAL models and divided
that by 9 for the "1 MHz" CPU clock, ending up more than 4% slower than
the NTSC boxes.