GATE EC 2020 Set 1 — Question 20
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Digital Circuits → Combinational Logic → MUX, DEMUX, Decoders & Encoders
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Question
The figure below shows a multiplexer where and are the select lines, to are the input data lines, EN is the enable line, and is the output.
is
is
Correct answer
(A) PQ + QR
Solution
From the figure: EN is active-low and tied to 0, so the MUX is enabled. The data inputs are , , , , with , .Combining the first two terms: , soCheck the others: (B) gives for , but the MUX outputs ; (C) gives for , but the MUX outputs ; (D) gives for , but the MUX outputs .Answer: (A)
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