Poetry is a good reason - Circuit riddle

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February 14th, 2010


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07:27 pm - Circuit riddle
There’s a box with three input signals: A, B, C. It has three output signals: ~A, ~B, ~C (that is, the negation of each input).

Design a circuit satisfying the above description. You have two NOT gates, and as many AND and OR gates as you like.

(If you solve this, don’t tell me the answer — I haven’t solved it yet; I just want to share the misery.)

(Not via avva.)
Current Music: Los Diablos - Un rayo de sol

(see my 7 | call my bluff)

Comments:


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From:tddpirate
Date:February 14th, 2010 08:56 pm (UTC)

Silly Questions

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1. Does the circuit have also a clock input?
2. Can I assume that the gates have delays?
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From:gaal
Date:February 16th, 2010 07:21 pm (UTC)

Re: Silly Questions

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I'm pretty sure there's no clock. I don't think you can assume #2 but I'll check with my source.
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From:shlomif
Date:February 18th, 2010 10:54 pm (UTC)

Re: Silly Questions

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Heh, heh, heh. Words of a true electrical engineer.
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From:gaal
Date:February 19th, 2010 06:03 am (UTC)

Re: Silly Questions

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No delays. Pure theoretical circuit.
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From:shlomif
Date:February 18th, 2010 10:59 pm (UTC)

I found a solution using a series of Perl programs

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Hi Gaal! After being immersed in this program for a long time, I've started writing a series of Perl 5 programs to explore and eventually solve them. You can find the sources for them online in their BitBucket Mercurial repository (no spoiler at the link, but you can browse to more offending stuff. Licence is the MIT/X11 Licence.

Without giving a spoiler, I should note that the solution my programs found was horribly complicated, and would have taken me a long time to reach. And it appears there's only one solution to this problem.

Just to let you know - do with this information as you please.

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From:gaal
Date:February 19th, 2010 06:04 am (UTC)

Re: I found a solution using a series of Perl programs

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Nice. I've not looked at the code or the solution. Just remember you can reuse the output of a subcircuit, in case that simplifies things.
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From:shlomif
Date:February 19th, 2010 07:11 am (UTC)

Re: I found a solution using a series of Perl programs

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Yes, I know that one can reuse the output of a subcircuit, and my programs take it into account.

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