Re: TED colors (was: vic-ii pal colors)

>
> As to why the actual palette is different from what the specs say, I
> know of no evidence. (As a wild guess, the palette hasn't been a
> critical factor; that is, whatever colours finally came out of the chip
> were "fine" as long as they didn't look particularly horrible... and
> IMHO they really didn't). Another guess: the specs were made while the
> actual design was still being worked on. Haven't heard of fundamental
> differences between HMOS-I and HMOS-II i.e. 7360 and 8360 TED palettes
> so far.)
>
> If you make measurements on the signals coming out of the video out
> port, be sure to terminate them with 75 ohm resistors to ground. That
> way, you're supposed to get value ranges comparable to those defined in
> the standards. (I assume, there's no equipment connected to the signals
> being measured, other than the oscilloscope probe.)
>

I have connected a Philips CM8833 to the video output and measured signal
levels before the RF modulator, which means directly on TED pins (using an
oscilloscope).
From my point of view I want to generate the same signal (from FPGA) that
comes out of TED (e.g. luma levels between 0v-4.4v, chroma levels 1v peak
to peak). This way the RF modulator will create the same output as with TED.


> There's also a small design flaw in all 264 series machines: there is a
> ferrite bead in series with the common ground point of the video out
> port, which (i.e. the common point that has non-negligible resistance
> above the 1-2MHz mark) causes crosstalk between the signals. (This is
> the main reason why the separate luma-chroma output image of these
> machines looks bad... there is so much crosstalk between luma and chroma
> that it introduces visible moire on the image). All in all... if you
> want to get rid of a disturbance factor, find and short the FB between
> the machine's and the socket's ground.
>

The crosstalk is bad on the composite output too.  Even using the Philips
CM8833 it is terrible. When I was kid I did not bother, but now I can see
it.
I will try this FB short to see whether it improves signal.

Regards,
Istvan