Thursday, 22 December 2011

DIGITAL ELECTRONICS IN APPLICATION...


Last day we had our first class on digital electronics and today Sir asked to design some logical circuits based on the facts that we have studied. Unlike the last time we were grouped into 2 with 4 members in each group. We were to solve 3 questions from among the 6 questions.

                             The questions selected by our group were

1. Design a full adder circuit.
2. Design a DFA to accept even number of zeroes.
3. Design a digital circuit to compare two 3 bit input.

   
                        Full adder circuit was the simplest question. We were to perform the add operation on 3 bit input. We implemented it using XOR and AND. The addition starts with the least significant bit  say z1 and z2 and the carry will be used as the third bit for the next two bits say y1 and y2. Thus it is continued.

                   Next was the comparator.  We consider two inputs A2 A1A0 and B2 B1 B0. To check if A and B were equal all the respective bits shall be equal. For A>B the cases can be:
A2=1 & B2=0
A2=1, B2=1.A1=1, B1=0
A2=1, B2=1, A1=1, B1=1, A0=1, B0=0
If the case is not any of these or A=B then it will be undoubtedly A<B

We implemented this circuit using four XNOR, one OR gate, two AND gates with three inputs, one AND gate with four inputs and one AND gate with two inputs.

                      Next was the circuit of a DFA to accept even number of zeroes. This was the most tiring circuit. We were not aware of the way by which we could give a sequential input and a random input too. Our circuit was found to be working for the ordered input 101010………

                  Even though we had a session on digital electronics as per the schedule of the day Miss didn’t turn up for some reasons and Mahesh Sir talked on some general topics. Sir was curious to know our parent’s opinion regarding the HPC classes.

Yes that was for the day. Had a good day at HPC as usual.

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