EICO 460 simulation

[Allan Adler]

Suppose that, working either from schematics and/or from a close examination
of an old EICO 460 oscilloscope, I obtain detailed information about how
it is put together. Is it then possible for me to use (hopefully free)
software to analyze the entire operation of the oscilloscope, or is that
too big a job for the available software? I'm inclined to think it is
entirely feasible, but I have no experience with electronics software.

I have two ancient EICO 460 oscilloscopes and a lot of documentation on
them, so this question is not entirely hypothetical.

Ignorantly,
Allan Adler
ara@zurich.ai.mit.edu

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* Disclaimer: I am a guest and *not* a member of the MIT Artificial *
* Intelligence Lab. My actions and comments do not reflect *
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[John Jardine]

Allan Adler <ara@nestle.ai.mit.edu> wrote in message
news:y93d6f3besa.fsf@nestle.ai.mit.edu...

Suppose that, working either from schematics and/or from a close
examination
of an old EICO 460 oscilloscope, I obtain detailed information about how
it is put together. Is it then possible for me to use (hopefully free)
software to analyze the entire operation of the oscilloscope, or is that
too big a job for the available software? I'm inclined to think it is
entirely feasible, but I have no experience with electronics software.

I have two ancient EICO 460 oscilloscopes and a lot of documentation on
them, so this question is not entirely hypothetical.

Ignorantly,
Allan Adler
ara@zurich.ai.mit.edu


****************************************************************************
*
*
* Disclaimer: I am a guest and *not* a member of the MIT Artificial
*
* Intelligence Lab. My actions and comments do not reflect
*
* in any way on MIT. Moreover, I am nowhere near the Boston
*
* metropolitan area.
*
*
*

****************************************************************************

It's a truly, truly brave man who will attempt that level of simulation from
scratch .
The answer is that Yes! it is feasible, (but not in it's entirety).
The circuitry you would finally get on screen could not include the very
important scope' tube. nor would any of the numerous switches and pots be
directly useable. Items such as the HT transformer would have to be modelled
specifically, even though that extreme level of detail will not be in the
documentation. Even with the best will in the world, the end result would
only be a simplified, rough approximation of the actual 'scope circuitry.
Simulation time would also be horrendously slow with numerous convergence
failures.
OTOH ... A complete functional block, something like that 'orribly
complicated looking 'Y' amplifier, or the 'X' timebase driver, would
simulate nicely and a lot could be learned.
Best of luck!
regards
john

 

[Allan Adler]

John Jardine wrote:

It's a truly, truly brave man who will attempt that level of simulation from
scratch .

I'm sure a very ignorant optimist will suffice.

The answer is that Yes! it is feasible, (but not in it's entirety).

It did seem like a lot to ask. On the other hand, I recall reading, maybe
10 years ago or more, that the advent of supercomputers offered the possibility
of simulating an entire airplane, instead of just parts of it which then had
to be assembled and tested to evaluate the ensemble. This was hailed as a
way of designing passenger planes that would fly near the top of the atmosphere
would get you from New York to Tokyo in half an hour. So, I just figured that
if they could contemplate that, why not my dinky little EICO 460?

The circuitry you would finally get on screen could not include the very
important scope' tube. nor would any of the numerous switches and pots be
directly useable.

I don't know what it means to simulate the oscilloscope tube in this context.
Does it mean to simulate it as a circuit element or does it mean to worry
about the electrons and fields and heat? I guess it means both, since
ultimately I'd want to know what is going to appear on the oscilloscope
screen.

I did a search of www.ams.org/mathscinet for math papers whose reviews
contain the words "cathode ray tube" and found a few that try to model
it directly and several which try to use the tube to present graphs of
solutions to differential equations and other problems. I can't say
without looking at the papers, but that does sound as though they must
have considered some aspect of the simulation problem for the crt in
order to do that.

Regarding the switches and pots, they describe the state of the scope. Part
of the simulation can be to let the user specify some functions that will
govern the state of the pots and switches at each moment of time. Likewise,
the device one is hoping to connect to the oscilloscope can be simulated
either by a function describing the input signal (treating the device as a
signal generator) or by writing the circuit for the device and grafting it
onto the circuit for the oscilloscope.

When I use words like "can" here, I don't necessarily mean possible,
merely conceivable at my low level of understanding.

Items such as the HT transformer would have to be modelled
specifically, even though that extreme level of detail will not be in the
documentation.

When you talk about modeling the HT (what is HT?) transformer specifically,
I gather that means you have to worry about details of its construction,
geometry and winding that you might only know from taking it apart. If you
did know all that, what kind of software would model it?

Alternatively, maybe one could remove the transformer and use a computer
controlled device to test it and store a lookup table of its behavior
under various conditions.

Even with the best will in the world, the end result would
only be a simplified, rough approximation of the actual 'scope circuitry.
Simulation time would also be horrendously slow with numerous convergence
failures.

Since my scopes are in storage, it will be faster than actually trying
to use them.

OTOH ... A complete functional block, something like that 'orribly
complicated looking 'Y' amplifier, or the 'X' timebase driver, would
simulate nicely and a lot could be learned.

I'll take a look at the schematics. Thanks for the suggestion.

Ignorantly,
Allan Adler
ara@zurich.ai.mit.edu

****************************************************************************
* *
* Disclaimer: I am a guest and *not* a member of the MIT Artificial *
* Intelligence Lab. My actions and comments do not reflect *
* in any way on MIT. Moreover, I am nowhere near the Boston *
* metropolitan area. *
* *
****************************************************************************