Just a question

Discussion in 'Homework Help' started by aceminer, Nov 5, 2011.

  1. aceminer

    Thread Starter New Member

    Aug 26, 2011
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    Hi guys,

    Just to check, is there any exam papers i could find on the net provided with solutions as my digital logic exam is just round the corner. Would appreciate greatly any material or exam papers. I am a Year 1 CS student anyway.
     
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Read through This

    It will help you a lot. Especially since it is FREE too!
     
  3. bertus

    Administrator

    Apr 5, 2008
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  4. aceminer

    Thread Starter New Member

    Aug 26, 2011
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    Hey bertus, thanks for the link but they are apparently too hard for me to understand. I am only a Year 1 student so the course i am undergoing is relatively introductory so do you have any other links which are relatively less complicated. To be honest, i couldnt even understand the questions or the answers in the worksheet.
     
  5. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Everything in the worksheet and quiz is covered in the link I posted.
     
  6. aceminer

    Thread Starter New Member

    Aug 26, 2011
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    Well i have a question which goes like this:

    Given an Equation :
    F = A'B'CD' + B'C'D + A'B'C' + AB'D
    use a 4x1 multiplexer with an enable input plus other gates
    draw out the circuit based on this equation. Anyway the enable is active-low.

    I do have the answer but i cannot seem to understand why do they use A and C inputs as the select bits whereas the D inputs are belonging to the 4 x 1 multiplexer with one input being constant. Could some1 kindly please explain to me.
     
  7. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Skip to Here and draw out the truth table for the expression.

    From there, look at the behavior of a 4-1 multiplexer with enable.

    The ' as in A' means NOT A, and AB means A AND B, A+B is A OR B, and A'B is NOT A AND B

    It's just a system of notation for text discussion of logic.
     
  8. Georacer

    Moderator

    Nov 25, 2009
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  9. aceminer

    Thread Starter New Member

    Aug 26, 2011
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    Hi. Thanks a lot guys! I think i figured my question and answer out. You guys are a great help!
     
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