Yin is always better than Yang - or vice versa - I forget.
What, a grammatical/spelling mistake? Is someone impersonating Mr
One of my favorite quotes about J.E.H is from the series Homicide.
Very like RO. In RO, you drill little holes in some plastic so that only
If you used a water jet cutter running on ultra pure water, the
Glass usually has metal impurities such as iron in it too.
that nothing is coming out of it below 800 , nor above 2700,
Is your scope that fast, that you can actually see the 1440 MHz ?
Sublimate the outside in a vacuum, and use the core.
Wow. May your sales stall big time for wasting our time ;-)
After you are done you have to clean out the hole. A chemical company
Not much.
Think of what he could have done with a department of "Homeland Security".
Yabbut, the point is, it's contrary to everything they said from day 1 of
Not to mention top-posting.
The data sheets for analog 4-quadrant multiplier-on-a-chip chips are
remarkably vague as to what goes on inside the chip. I'm thinking
specifically of the Anaalog Devices AD633 and the Burr-Brown MPY634,
which are (at my level of viewing) similar in overall function and
specs (but different in some details.)
Some thoughts:
1. One-quadrant multiplying doesn't seem too hard. Take the logs, add
the logs, exponentiate the log. Basic building blocks are things I
think I understand pretty well.
2. Four-quadrant multiplying is still somewhat a mystery. The AD633
just says it has a "translinear core". I have about as much
understanding of that as if they had said "dilithium crystals". The
MPY634 data sheet doesn't even say that much, it just jumps right into
an equation without relating it to any internal functions.
3. Maybe a four-quadrant multiplier can be done with a one-quadrant
multiplier, some absolute-value-taking circuits, and some comparators,
and a final multiply-by x1 or x-1 depending on the comparators.
4. One clue that the MPY634 and AD633 don't use the method I suggest
in (3) is a lack of symmetry in the X and Y inputs. One input always
has a linearity of maybe 4 times better linearity than the other. This
indicates to me that internally there is some assymetry that isn't
necessarily implied by my simple suggestion.
5. Maybe the "translinear core" is something like a Gilbert cell. Or
is it just a clever application of the Barrie patent that describes how
things like the AD603 work? (See my thread here from September about
how the AD603 works.) Even then that only gets you two quadrants...
but there is an assymetry in the input such that maybe some other trick
comes in.
So how many of my 5 thoughts above are completely and hopelessly wrong?
All 5?
If there's some Barrie patent that explains all this, I'd love to read
it. When I've been pointed directly towards them in the past, they were
always a joy to read. But I've got an exceptionally thick head and
unless I'm pointed towards a specific one my eyes still glaze over in
the claims section :-(
Tim.
I'll take that for a zero.
Nothing to this specific disaster, but we give a few K a year to DWB,
So many people expect somebody else, somebody better off, to do the
ok, noted.
yup, goes up to 4GHz.
