You wrote:
> If you could refresh my memory... Did Atari use the multipliers for the
> BIP control? Size was just a matter of gain in the op-amps, no?
>From my Space Duel docs (which I conveniently have at work ;-) here is what I see:
A couple transistors are used to generate a DAC reference voltage and are
tied to the BIP pots.
The output of the BIP pots is tied to the IO output of the 6012 DACs on ach axis
The analog signal then goes through a couple op amps with the video invert
circuitry and !CENTER bypass (equivalent of the 13331 in the cinematronics
circuit, I assume)
The X output then splits, with one leg going to a 1495 that an XCOR signal to
the Y axis 1495, and the other leg going to the X axis 1495. The equivalent
happens on the Y circuit, so a YCOR signal comes into the X 1495 as well.
The XSIZE pot feeds into the X axis 1495,
The XCENTER pot sits on the output of the 1495 (adjusts DC bias level), which
is also tied to the next op amp in the chain, which feed the XLIN pot, which
then feeds the output buffer.
My read is that the BIP pots help set the bias in the linear range. It seems
that a correction multiplier needs to be applied to each axis, depending on
where the other axis is, which is why the correction signals are fed into the
multipliers for each axis.
If folks don't have this schematic, e-mail me a FAX number and I can send it out.
Since people have mentioned that the Boxing Bugs translator board also has a
couple 1495s, I think it is safe to assume that the WG monitors need a
correction multiplier to compenate for non-orthogonalities between the signals
to the axes?
Ray
