Karnaugh map decomposition

Discussion in 'Homework Help' started by transistortransistor, Jan 21, 2014.

  1. transistortransistor

    Thread Starter New Member

    Oct 9, 2013
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    Hello everyone,

    I need to implement the following function:

    f(A,B,C) = (sum of the miniterms 2,4,5,6)

    I can only use 4 NAND gates with two inputs. A,B,C complement are not available.

    The question suggests that I should use K-Map Decomposition.

    My question is: how am I supposed to use this technique? should I magically know how each operation looks on a K-map and think of ways to gather them?
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    You are supposed to have been shown how to draw Karnaugh maps.

    Draw a Karnaugh map for three variables A, B and C.

    Show the minterms 2, 4, 5, and 6 on the map. Then we'll guide you from there.
     
  3. transistortransistor

    Thread Starter New Member

    Oct 9, 2013
    11
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    [​IMG]

    Ok, whats the next step?
     
  4. t06afre

    AAC Fanatic!

    May 11, 2009
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    We do not mind helping in this section of forum. But we will not just serve you a solution on a silver plate. In this case it is quite apparent that you have not done much reading in your books or lecture notes. Anyway try to read this http://www.uotechnology.edu.iq/dep-eee/lectures/1st/Digital techniques/part2.pdf Then feel free to come back with your questions
     
  5. MrChips

    Moderator

    Oct 2, 2009
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    Group the 1s in powers of 2 (pairs, quads etc.) and write them down as sums of products.
     
  6. transistortransistor

    Thread Starter New Member

    Oct 9, 2013
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    Hello MrChips, thanks for helping.

    Anyway, I know how K-Maps works.

    [​IMG]

    In this case, I would use 3 NAND's to get the "complement" of the variables + 3 NANDS to the products (BC, AC, AB) + 1 NAND with three inputs to get the final function.

    But the question says that I need to use just 4 two input NAND.

    And then it suggests K-Map decomposition.

    Here a image of an example:

    [​IMG]

    Thats why I said "guess". It's not guessing, but I would need to know beforehand how AND/ORS or any other operation look on K-MAP so I would be able to gather them and get my function.
     
  7. MrChips

    Moderator

    Oct 2, 2009
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    If you know how K-Maps work then what is your question?
     
  8. transistortransistor

    Thread Starter New Member

    Oct 9, 2013
    11
    0
    It's about k-map "decomposition"

    Please, take a look at the example of my lecture slide:

    http://postimg.org/image/ed1e2mlqn/
     
  9. WBahn

    Moderator

    Mar 31, 2012
    17,757
    4,800
    So what on earth is preventing you from drawing the K-Map for A AND B and/or A OR B and seeing what it looks like on a K-MAP?
     
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