How to convert Excess 3 to Binary 4-bit?

Discussion in 'Homework Help' started by ajprameswari, Oct 13, 2011.

  1. ajprameswari

    Thread Starter New Member

    Oct 13, 2011
    3
    0
    I need to convert Excess 3 to binary 4-bit and implement it into K-Map and combinational circuit.

    What makes me confused is..

    Do I need to start the input in Truth Table from -3 and set the output to Don't care?

    This is what I meant.

    Decimal Excess-3 Binary 4-bit
    A B C D W X Y Z
    ---------------------------------
    -3 0 0 0 0 X X X X
    -2 0 0 0 1 X X X X
    -1 0 0 1 0 X X X X
    ---------------------------------
    0 0 0 1 1 0 0 0 0
    1 0 1 0 0 0 0 0 1
    2 0 1 0 1 0 0 1 0
    3 0 1 1 0 0 0 1 1
    4 0 1 1 1 0 1 0 0
    5 1 0 0 0 0 1 0 1
    6 1 0 0 1 0 1 1 0
    7 1 0 1 0 0 1 1 1
    8 1 0 1 1 1 0 0 0
    9 1 1 0 0 1 0 0 1
    10 1 1 0 1 1 0 1 0
    11 1 1 1 0 1 0 1 1
    12 1 1 1 1 1 1 0 0
    ---------------------------------
    13 X X X X 1 1 0 1
    14 X X X X 1 1 1 0
    15 X X X X 1 1 1 1


    Do I need to set the Outpout of dec(-3,-2, and -1) into (1101, 1110, and 1111) as signed bit for negative?

    Any help would really be appreciated.
    Thanks
     
  2. Georacer

    Moderator

    Nov 25, 2009
    5,142
    1,266
    It really depends on the purpose of your circuit, which you have not shared with us.

    Is that thread of any help?
     
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