Logic circuit Representation
Difference
| Combinational | Sequential |
|---|---|
| No memory | Memory |
| No feedback loops | Feedback loops |
| Output depend only on the current input | Output depend on the input and current state |
Representation
Truth Table :
- Unique signature of a boolean function
- Expensive representation Boolean Function :
- Can have many alternative boolean expressions
- Different boolean expressions lead to different gate realizations Canonical Form : Provide a unique algebraic signature
- Sum of miterms
- Product of maxterms
Canonical forms
Sum of Products (SOP)
- Minterm : Product of literals (AND)
- Each row has a minterm
- Each minterm is true for that row and only that row
- Find all input combinations for which the output of the function is True
We can also write the sum of products as
Product of Sums (POS)
- Maxterm : Sum of literals
- Each row has maxterm
- Each maxterm is false for that row and only that row
- Find all input combinations for which the output of the function is False
We can also write the product of sums as