Good Composite->VGA converters for classic computers (& video games...)

[Eric Smith]

Josh wrote:
> Anyone out there use a composite->VGA upscaler for their classic
> computing and/or gaming needs?
[...]
and about a specific model:
> it gets really confused by the composite signal coming from other
> systems (like the Apple II and Sega Genesis) and is unusable with them.

The problem with the Apple II is that it does NOT produce NTSC video,
but rather something close enough to fool an analog television set or
monitor.  The timings are deliberately wrong, especially the frequency
and phase relationships of the color subcarrier to the horizontal
sync.

Converters use commodity NTSC decoder chips that get confused
by signals with significant deviations from standard NTSC.