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GATE CS Digital Logic questions

Practise Digital Logic questions for GATE CS. Explore official PYQs and original subject-wise quizzes, check answers and view available solutions. Free, no sign-in.

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Official PYQ2012Digital LogicCombinational CircuitsMCQ · 1 mark
The amount of ROM needed to implement a 4-bit4\text{-bit} multiplier is
Official PYQ2012Digital LogicNumber Representations (Fixed and Floating Point)MCQ · 1 mark
The decimal value 0.50.5 in IEEE single precision floating point representation has
Official PYQ2012Digital LogicBoolean AlgebraMCQ · 1 mark
The truth table XY(X,Y)000010101111{\begin{array}{|c|c|c|}\hline \textbf{X}& \textbf{Y}& \textbf{(X,Y)} \\ \hline 0& 0& 0 \\ \hline 0& 1&0\\ \hline 1& 0& 1 \\ \hline 1& 1& 1 \\ \hline \end{array}} represents the Boolean function
Official PYQ2011Digital LogicCombinational CircuitsMCQ · 1 mark
Consider the following circuit involving three D-type flip-flops used in a certain type of counter configuration. If all the flip-flops were reset to 00 at power on, what is the total number of distinct outputs (states) represented by PQRPQR generated by the counter?
Official PYQ2011Digital LogicSequential CircuitsMCQ · 1 mark
Consider the following circuit involving three D-type flip-flops used in a certain type of counter configuration. If at some instance prior to the occurrence of the clock edge, P,QP, Q and RR have a value 00, 11 and 00 respectively, what shall be the value of PQRPQR after the clock edge?
Official PYQ2011Digital LogicSequential CircuitsMCQ · 1 mark
The minimum number of D\text{D} flip-flops needed to design a mod-258 counter is
Official PYQ2011Digital LogicMinimization (K-Maps etc.)MCQ · 1 mark
The simplified SOP (Sum of Product) from the Boolean expression (P+Qˉ+Rˉ).(P+Qˉ+R).(P+Q+Rˉ)(P + \bar{Q} + \bar{R}) . (P + \bar{Q} + R) . (P + Q +\bar{R}) is
Official PYQ2010Digital LogicCombinational CircuitsMCQ · 1 mark
In the sequential circuit shown below, if the initial value of the output Q1Q0Q_1Q_0 is 0000. What are the next four values of Q1Q0Q_1Q_0?
Official PYQ2010Digital LogicCombinational CircuitsMCQ · 1 mark
What is the boolean expression for the output ff of the combinational logic circuit of NOR gates given below?
Official PYQ2010Digital LogicCombinational CircuitsMCQ · 1 mark
The Boolean expression of the output ff of the multiplexer shown below is
Official PYQ2010Digital LogicNumber Representations (Fixed and Floating Point)MCQ · 1 mark
PP is a 1616-bit signed integer. The 22's complement representation of PP is (F87B)16(F87B)_{16}. The 22's complement representation of 8×P8\times P is
Official PYQ2010Digital LogicCombinational CircuitsMCQ · 1 mark
The main memory unit with a capacity of 44 megabytes\text{megabytes} is built using 1M×1-bit1\text{M} \times \text{1-bit} DRAM chips. Each DRAM chip has 1K1\text{K} rows of cells with 1K1\text{K} cells in each row. The time taken for a single refresh operation is 100  nanoseconds100\; \text{nanoseconds}. The time required to perform one refresh operation on all the cells …
Official PYQ2010Digital LogicBoolean AlgebraMCQ · 1 mark
The minterm expansion of f(P,Q,R)=PQ+QRˉ+PRˉf(P,Q,R) = PQ +Q \bar{R}+P\bar{R} is
Official PYQ2009Digital LogicSequential CircuitsMCQ · 1 mark
Given the following state table of an FSM with two states AA and BB,one input and one output. …
Official PYQ2009Digital LogicCombinational CircuitsMCQ · 1 mark
How many 32K×132K \times 1 RAM chips are needed to provide a memory capacity of 256K256K bytes?
Official PYQ2009Digital LogicCombinational CircuitsMCQ · 1 mark
What is the minimum number of gates required to implement the Boolean function (AB+C)\text{(AB+C)} if we have to use only 2-input NOR2\text{-input NOR} gates?
Official PYQ2009Digital LogicNumber Representations (Fixed and Floating Point)MCQ · 1 mark
(1217)8(1217)_8 is equivalent to
Official PYQ2008Digital LogicBoolean AlgebraMCQ · 1 mark
If P,Q,RP, Q, R are Boolean variables, then (P+Qˉ)(P.Qˉ+P.R)(Pˉ.Rˉ+Qˉ)(P + \bar{Q}) (P.\bar{Q} + P.R) (\bar{P}.\bar{R} + \bar{Q}) simplifies to
Official PYQ2008Digital LogicBoolean AlgebraMCQ · 1 mark
Given f1f_1, f3f_3 and ff in canonical sum of products form (in decimal) for the circuit f1=Σm(4,5,6,7,8)f_1 = \Sigma m(4, 5, 6, 7, 8) f3=Σm(1,6,15)f_3 = \Sigma m(1, 6, 15) f=Σm(1,6,8,15)f = \Sigma m(1, 6, 8, 15) then f2f_2 is
Official PYQ2008Digital LogicNumber Representations (Fixed and Floating Point)MCQ · 1 mark
Let rr denote number system radix. The only value(s) of rr that satisfy the equation 121r=11r\sqrt{121_r}={11}_r is/are