Analysis Procedure

Analysis Procedure   AU Dec.-11,12, May-15

Steps to analyse combinational circuit

1. First make sure that the given circuit is combinational circuit and not the sequential circuit. The combinational circuit has logic gates with no feedback path or memory elements.

2. Label all gate outputs that are a function of input variables with arbitrary symbols, and determine the Boolean functions for each gate output.

3. Label the gates that are a function of input variables and previously labeled gates and determine the Boolean function for them.

4. Repeat the step 3 until the Boolean function for outputs of the circuit are obtained.

5. Finally, substituting previously defined Boolean functions, obtain the output Boolean functions in terms of input variables.

Example 1.10.1 Analyse the combinational circuit shown in Fig. 1.10.1 to determine the truth table and the Boolean expressions governing the outputs of the circuit.         AU: Dec.-12, Marks 10

Example 1.10.2 Consider the combinational circuit shown in Fig. 1.10.2.

i) Derive the Boolean expressions for T₂ through T₄ . Evaluate the outputs F₁ and F₂  as a function of the four inputs.

ii) List the truth table with 16 binary combinations of the four input variables. Then list the binary values  T₁ through T₂  for and outputs F₁ and F₂  in the table.

iii) Plot the output Boolean function obtained in part (ii) on maps and show that simplified Boolean expressions are equivalent to the ones obtained in part (i)           AU: Dec.-11, Marks 16

The simplified Boolean expressions are equivalent to the ones obtained in part (i). 

Example 1.10.3 Explain the analysis procedure. Analyze the following logic diagram.  AU May-15, Marks 8