Re: RosAsm?

From: Evenbit (nbaker2328_at_charter.net)
Date: 04/18/04 

Date: 18 Apr 2004 06:10:43 -0700

The Wannabee <shakainzulu@hotmail.com> wrote in message news:<opr55101lnvbbpro@news.broadpark.no>...
[SNIP]
> Would this be possible ? I know its kind of lame question, but is technoly
> today so good that it would be possible to distiguigh more than one
> voltage level in a transistor ? What I am getting at is this :Wouldnt that
> make better use of transistors ? I mean if you could store a byte or
> longint value in each by storing a more accurate voltage level ? Wouldnt
> that make them much more valuable ?

Already been done, been in extremely popular use for decades, it
landed the first man on the moon, and is exactly what the binary
digital system was designed to counter because of its limits. What
the heck am I talking about? Well, let us take your scenario to the
extreme. Why stop at a 3-state device when a 5-state one would be
better? Heck, why stop at 5-state when a 500-state device would be
even better still? Forget that...our competitor took his device to
infinity! Wait! An infinite number of states would mean that we have
an ANALOG device, right? Right! That is why I said... Already been
done, been in extremely popular use for decades, it landed the first
man on the moon, and is exactly what the binary digital system was
designed to counter because of its limits.

Analog circuits are the foundation of our communications (television,
radio, telephone) infrastructure. It is limited by the fact that its
function is determined in hardware (by the designer) and is seldom
capable of being determined by the information {software} passing
through it (by the user). But you are wrong if you assume that analog
devices cannot be computing devices. The mechanical watch or clock is
an excellent example. The gears perform an analog computation of the
time…the face and hands convert this analog movement into digital form
with the help of digits (either the Arabic numerals 0-9 or the roman
numerals I, III, VI, IX and tic marks) at the appropriate spots.
Think about the drive train in an automobile. Look at the rear axle
of a pickup truck. In the center is a bulbous area where the drive
shaft attaches. We call this the pumpkin. Inside are what we call
spider gears…gears that are arranged so that the wheel on one side of
the truck can rotate faster than the wheel on the other side of the
truck when the truck is taking a turn. The technical name for the
pumpkin is differential. But you'd be wrong if you conclude that this
name refers simply to the speed DIFFERENCE between the two sides.
Take a calculus class and learn about derivatives and integrals: the
process of finding the derivative for a given function is called
differentiation. Wooh-Hoo! This analog device can calculate
derivatives and integrals in real-time!

Now, how did we put a man on the moon without using modern day 3GHz
CPUs for navigation? "Ground Control to Major Tom." How do I monitor
my speed and distance in the vacuum of space? There are no mile
markers here. And no asphalt for my wheels to run on so my
speedometer and mileage indicator aren't working. My altimeter
stopped working too! "Major Tom to Ground Control!!!!!!" Well, let
us start with simple math. Velocity is distance * time (v = d * t, or
the derivative of distance to time in calculus terms). Acceleration
is velocity * time (a = v * t, or the derivative of velocity to time
in calculus terms). Now, it is fairly easy to construct an
accelerometer (a device that senses accelerations). And, it is fairly
easy to construct an analog electrical circuit that performs
integrals. So, if we attach to our spaceship an accelerometer for
each direction of movement and one for each axis of spin, and we
attach to each of these an integrator to compute the integral of
acceleration to give us velocity for that particular time, and we
attach to each of these an integrator to compute the integral of
velocity to give us distance for that particular time, then we can
navigate our USS Enterprise 1701-Z just fine provided we have a
stellar map and some knowledge of orbital mechanics.

An area where analog (or infinite digital) electronics really trumps
binary digital electronics is in transmission. Flip a flashlight on
and then flip it off. Then on again, then off, then on, off, on,
off… etc. While you do this, keep track of the time that it is on and
the time that it is off. Draw a graph of this data. This graph is
what we call a square wave. It is composed of straight lines (exactly
vertical and exactly horizontal) and sharp corners. Very different
from a sine wave. You can draw a sine wave by thinking of firing a
model rocket in a light wind without a parachute. At launch, the
rocket travels almost straight up rather fast but eventually starts
slowing down and being pushed to the side by the wind. At the very
top of its flight, the rocket is no longer gaining altitude, but it
will be travelling sideways (and thus no longer being straight
overhead of the launch point) a good distance because of the wind. As
the rocket falls, it gains speed and its path becomes less affected by
the wind with respect to the time of travel, thus, at the end of its
journey, it falls nearly straight down to the ground. THUD [then I
go cry to my mother that my rocket is destroyed because the parachute
failed to open ;-)] The path this rocket traveled represents one-half
of a sine wave. The other half would be if the rocket were to
magically dig its way into the ground and follow a similar (but upside
down) trajectory and coming out again some distance ahead. A good
example of a sine wave is what you get at a wall socket. In the US,
it is 120 volts rms (root-mean-squared, the direct current ‘DC'
{square wave} equivalent) at 60 hertz. So, graphing this out, the
voltage starts at zero volts and quickly rises, approaching 120 volts,
actually peaks somewhere above 120 volts, then drops back toward zero
volts where the polarity switches (the negative wire becomes the
positive wire and the positive wire becomes negative / the current
flows the opposite direction), so the voltage quickly rises,
approaching -120 volts, actually peaks somewhere below -120 volts,
then drops back toward zero volts where the polarity switches, etc….
60 hertz means it is doing this positive/negative cycle 60 times per
second. ANYWAY.... That all said and done, allow me to get to the
POINT here. It is much easier for sine waves to travel through
circuits and arrive on the other end almost completely in tact than it
is for square waves. And the reason why is because of harmonics.
Yes, this involves complex math again, but I will simplify. Take a
sine wave, say 60Hz, now double it = 120Hz. 120Hz is the first
harmonic of 60Hz. Now double the 120Hz sine wave = 240Hz. 240Hz is
the second harmonic of the 60Hz wave. Now, pause for a moment and
combine the 60Hz with the 120Hz with the 240Hz into one wave and look
at it carefully. My Lord! There is a sort of pattern taking shape in
this waveform. Could it be? Yes, it is beginning to look like a very
rough, scetchy approximation of a square wave. And it keeps looking
more and more like a square wave as I add higher and yet higher
harmonic frequencies to the composite waveform. But it will never
look like a PERFECT square wave until I add an INFINITE number of
harmonics to it. SO, a square wave is ACTUALLY made up of an infinite
number of harmonic frequencies! Now, talk about bandwidth! Are you
really going to be able to design a circuit that passes an infinite
number of frequencies? Take a look at the standard telephone service.
 Normal human hearing is 20Hz to 20kHz. But the telephone service
cuts off big chunks at both ends of this range. Why? Because it
saves money, reduces design headaches, and nobody notices anyway (very
Eeor-like there ;-). Circuits work best when they don't have to deal
with a large range of frequencies. So, if I were designing a phone, I
would perhaps use three circuits...1) one that responds well at the
low frequencies near 20Hz, 2) one that responds to the mid-range
frequencies, and 3) one that responds to the high frequencies near
20kHz. HOWEVER, nobody would buy this phone! It is too expensive.
It has 3-times the number of components and 3-times the amount of
complexity that the competitor brand has. The competitor brand phone
has only one circuit responding to the mid-range frequencies.

Now, try pushing a square wave through the narrow bandwidth of the
standard telephone service. Very difficult! But there are tricks to
the trade and engineers are always looking for ways accomplish the
impossible. That's why we had the gradual increase in modem speeds...
300 baud, then 600 baud, 1200, as they discovered new ways to make the
square wave increasingly appear non-square....and then hitting a brick
wall at about 56kbps.

Well, this post is becoming Bethonian, so I'd better stop here. Just
pretend that this post goes on to discuss hugging trees, standing in
front of tanks, and doing these things in a massively parallel and
non-centralized manner. Crap! I almost forgot the trademark... And
that's the beauty of Mr. Analog's design. ;-)

L8r...

Evenbit.

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