Combinational-Circuits
Question 1 |
The amount of ROM needed to implement a 4 bit multiplier is
64 bits | |
128 bits | |
1 Kbits | |
2 Kbits |
Question 1 Explanation:
To implement a 4-bit multiplier we need to store all the possible combinations of 24 x 24 inputs and their corresponding 8 output bits. The total ROM size needed = 28 x 8 bits = 211 bits = 2 Kbits.
Hence option D is the answer.
Hence option D is the answer.
Question 2 |
A circuit outputs a digit in the form of 4 bits. 0 is represented by 0000, 1 by 0001, ..., 9 by 1001. A combinational circuit is to be designed which takes these 4 bits as input and outputs 1 if the digit ≥ 5, and 0 otherwise. If only AND, OR and NOT gates may be used, what is the minimum number of gates required?
2 | |
3 | |
4 | |
5 |
Question 2 Explanation:
= A + BD + BC
= A + B (D + C)
So minimum two OR gates and 1 AND gate is required. Hence, in total minimum 3 gates is required.
Question 3 |
In the following truth table, V = 1 if and only if the input is valid.
What function does the truth table represent?
Priority encoder | |
Decoder | |
Multiplexer | |
Demultiplexer |
Question 3 Explanation:
It is a 22 × 2 encoder. The inputs have priorities. So, it is a priority encoder.
Question 4 |
Which of the following logic operations is performed by the following given combinational circuit?
EXCLUSIVE-OR | |
EXCLUSIVE-NOR | |
NAND | |
NOR |
Question 4 Explanation:
There are 4 questions to complete.