How To Implement This Function With 2 Input Nand

  • Thread starter Thread starter transgalactic
  • Start date Start date
  • Tags Tags
    Function Input
AI Thread Summary
The discussion focuses on implementing a function using only two-input NAND gates, specifically for the expression F(w,x,y,z) = (w'+x'+y')(+)xyz. Participants suggest transforming the function into a Sum of Products (SOP) format, which can then be modified for NAND implementation. A key point is the application of DeMorgan's theorem to derive alternative forms of the function, emphasizing the use of NAND gates as inverters. The conversation also highlights the importance of simplifying the expression by considering logical identities, such as A + AB = A. The final goal is to achieve a workable form of F suitable for implementation with NAND gates.
transgalactic
Messages
1,386
Reaction score
0
Default How To Implement This Function With 2 Input Nand..
(+) =XOR

F(w,x,y,z)=(w'+x'+y')(+)xyz

i tried to :

F(w,x,y,z)=(w'+x'+y')(+)xyz=(w'+x'+y')' *(xyz) + (w'+x'+y')(xyz)'=
=(wxy)(xyz)+(w'+x'+y')(x'+y'+z')
..
..
in the end i get
=wxyz+w'x'+w'y'+w'z'+x'+x'y'+x'y'+y'+y'z'+y'z'

what to do know?
how to transform implement it with a two input line NANDs
?
 
Physics news on Phys.org
Well, the word NAND should scream Sum of Products (SOP), so try to get your function to that point, then you can modify it further. After playing around with your function, you should get something like:

F = \overline{x} + \overline{y} + (\overline{w})(\overline{z}) + wxyz

(Keep in mind that A+AB = A; your final equation doesn't take that into account).

I'm going to show you another useful proof:

\overline{ABCD} = \overline{A}+\overline{B}+\overline{C}+\overline{D} = (\overline{A}+\overline{B})+(\overline{C}+\overline{D}) = \overline{AB}+\overline{CD} = \overline{(\overline{AB})(\overline{CD})}

The function is also equal to (through DeMorgan):
F = \overline{xy ( \overline{ \bar{w} \bar{z} })( \overline{wxyz}) }

Use the proof above on that form of F. Use the proof above to get \overline{(wxyz)}, too. Use NANDs as inverters to get w' and z'.
 
I think There is a mistake it should be \overline{AB}+\overline{CD} = \overline{({AB})({CD})}
 
Back
Top