Conversion to Bubble Logic

 

-       Logic output function can be determined directly from the diagram, without keeping track of complements if bubble output is connected to bubble input.

 

Example

a

b

a’

b’

P

0

0

1

1

0

0

1

1

0

0

1

0

0

1

0

1

1

0

0

1

 

P = a * b

 

-       Logic diagram can be converted to bubble logic by applying De Morgan’s rule.

 

Procedure:

 

-       Start at the output gate.  Connect any output gate that has a logic-level mismatch. (logic-level mismatch: low-active output to a high-active input or vice versa)

-       Reduce the output gate to conform the conversion convert next level of mismatch, so that logic levels between inputs & outputs are matched.

-       Redraw diagram.

-       Repeat the process until no more rematches are present.