Digital Logic


Q11.

Consider the minterm list form of a Boolean function F given below. F(P,Q,R,S)=\sum m(0,2,5,7,9,11)+d(3,8,10,12,14) Here, m denotes a minterm and d denotes a don't care term. The number of essential prime implicants of the function F is ______.
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Q12.

In the diagram above, the inverter (NOT gate) and the AND-gates labeled 1 and 2 have delays of 9, 10 and 12 nanoseconds (ns), respectively. Wire delays are negligible. For certain values a and c, together with certain transition of b, a glitch (spurious output) is generated for a short time, after which the output assumes its correct value. The duration of glitch is:
GateOverflow

Q13.

Let \bigoplus and \bigodot denote the Exclusive OR and Exclusive NOR operations, respectively. Which one of the following is NOT CORRECT?
GateOverflow

Q14.

The 2-input XOR has a high output only when the input values are
GateOverflow

Q15.

What is the minimum number of two-input NAND gates used to perform the function of two-input OR gate?
GateOverflow

Q16.

Given f(w,x,y,z) = \sum_{m} (0,1,2,3,7,8,10) + \sum_{d} (5,6,11,15), where d represents the don't care condition in Karnaugh maps. Which of the following is a minimum product-of-sums (POS) form of f(w,x,y,z) ?
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Q17.

If w, x, y, z are Boolean variables, then which one of the following is INCORRECT ?
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Q18.

Consider the Karnaugh map given below, where x represents "don't care" and blank represents 0. Assume for all inputs (a, b, c, d) the respective complements (\bar{a},\bar{b},\bar{c},\bar{d}) are also available. The above logic is implemented 2-input NOR gates only. The minimum number of gates required is ____________.
GateOverflow

Q19.

The simplified SOP (Sum of Product) from the Boolean expression(P + \bar{Q} + \bar{R}) . (P + {Q} + R) . (P + Q +\bar{R})is
GateOverflow

Q20.

The minimum Boolean expression for the following circuit is
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