Digital Logic
Q61.
If half adders and full adders are implements using gates, then for the addition of two 17 bit numbers (using minimum gates) the number of half adders and full adders required will beQ62.
Consider the two cascaded 2-to-1 multiplexers as shown in the figure. The minimal sum of products form of the output X isQ63.
Consider the following combinational function block involving four Boolean variables x, y, a, b where x, a, b are inputs and y is the output. f (x, y, a, b) { if (x is 1) y = a; else y = b; } Which one of the following digital logic blocks is the most suitable for implementing this function?Q65.
How many programmable fuses are required in a PLA which takes 16 inputs and gives 8 outputs? It has to use 8 OR gates and 32 AND gates.Q66.
A half Combinational Circuit is implemented with XOR and AND gates. A full Combinational Circuit is implemented with two half Combinational Circuits and one OR gate. The propagation delay of an XOR gate is twice that of an AND/OR gate. The propagation delay of an AND/OR gate is 1.2 microseconds. A 4-bit ripple-carry binary Combinational Circuit is implemented by using four full Combinational Circuits. The total propagation time of this 4-bit binary Combinational Circuit in microseconds is____________.Q67.
Consider an eight-bit ripple-carry Combinational Circuit for computing the sum of A and B, where A and B are integers represented in 2's complement form. If the decimal value of A is one, the decimal value of B that leads to the longest latency for the sum to stabilize is ________.Q68.
How many 3-to-8 line decoders with an enable input are needed to construct a 6-to-64 line decoder without using any other logic gates?Q69.
In a 8-bit ripple carry adder using identical full adders, each full adder takes 34 ns for computing sum. If the time taken for 8-bit addition is 90 ns, find time taken by each full adder to find carry.