How Do You Identify XOR in Karnaugh Maps?

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Discussion Overview

The discussion revolves around identifying the XOR operation in Karnaugh Maps (K-maps) and obtaining the minimum Boolean expression from a given map. Participants explore techniques for grouping ones and zeros in the K-map, particularly focusing on the parity conditions necessary for XOR logic.

Discussion Character

  • Homework-related
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant expresses confusion about circling groups in the K-map, noting the requirement for odd parity of ones and even parity of zeros.
  • Another participant suggests circling the four "0" entries for not A, indicating that this approach does not yield nice square blocks due to the nature of XOR.
  • A different participant proposes a specific grouping strategy, identifying the black box as ##\bar a## and the others as ##b##, ##c##, and ##d##, leading to the expression ##z = \bar a \oplus b \oplus c \oplus d##.
  • One participant provides a detailed breakdown of the Boolean expression derivation, listing out all the ones and applying various Boolean algebra techniques, ultimately arriving at an expression involving XOR and XNOR operations.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best method for circling in the K-map or the final expression. Multiple approaches and interpretations are presented, indicating ongoing debate and exploration of the topic.

Contextual Notes

The discussion includes various assumptions about the properties of XOR and XNOR, as well as the specific configurations of the K-map that may affect the grouping strategy. Some mathematical steps remain unresolved, and participants rely on different interpretations of the Boolean expressions.

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Homework Statement



Using XK-map techniques, obtain the minimum Boolean expression for the following map:

Screen Shot 2015-04-19 at 1.58.29 PM.png


Homework Equations

The Attempt at a Solution



So I've been doing some reading and I found this has to do with Reed Muller logic. This was unfortunately not covered in the course I'm taking, so I'm a tad bit confused.

How exactly am I supposed to circle this map? I know I have to circle groups of zeroes and ones such that the parity of the ones is odd and the parity of the zeroes is even.

For reference, the answer is listed as:

$$Z = \bar a \bigoplus b \bigoplus c \bigoplus d$$

I have experimented with a few circling combinations, but cannot find one that gives the answer above.
 
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You could "circle" the four "0" for not A i guess. They all have odd parity for B,C,D. Similar for A.
That does not give nice square blocks - it cannot, you are looking for XOR.
 
After staring at this for a few more minutes, I came up with this:

Screen Shot 2015-04-19 at 1.58.29 PM.png


So the black box would be ##\bar a##. The red box would be ##b##. The blue box would be ##c##. The green box would be ##d##.

So ##z = \bar a \oplus b \oplus c \oplus d##.
 
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I am in high school and my Computer Science teacher teach us this and I figure it out by kinda like a Math way.
First I list out all the 1s.
A'B'C'D'+A'B'CD+A'BC'D+A'BCD'+ABC'D'+ABCD+AB'C'D+AB'CD'
=(A'B'C'D'+A'BCD'+ABC'D'+AB'CD')+(A'B'CD+A'BC'D+ABCD+AB'C'D)
=D'(A'B'C'+A'BC+ABC'+AB'C)+D(A'B'C+A'BC'+ABC+AB'C')
=D'(C'[A'B'+AB]+C[A'B+AB'])+D(C[A'B'+AB]+C'[A'B+AB'])
RECALL THAT
A'B + AB' = A XOR B
A'B' + AB= A XNOR B

=D'(C'[A XNOR B]+C[A XOR B]) + D(C[A XNOR B]+C'[A XOR B])
WHILE XNOR = (XOR)'
=D'(C'[A XOR B]'+C[A XOR B]) + D(C[A XOR B]'+C'[A XOR B])
=D'([A XOR B] XNOR C)+ D([A XOR B] XOR C)
=D'(A XOR B XOR C)' + D(A XOR B XOR C)
=A XOR B XOR C XNOR D
=A ⊕ B ⊕ C ⊕ D'
OR IF U PULL OUT 'A' AT FIRST IT WILL BE THE SAME
 

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