GATEverse — GATE CSE previous year questions

Consider a digital display system $\text{(DDS)}$ shown in the figure that displays the contents of register $\text{X}.$ A $16 – \text{bit}$ code word is used to load a word in $\text{X},$ either from $\text{S}$ or from $\text{R}.$ $\text{S}$ is a $1024-$ word memory segment and $\text{R}$ is a $32-$ word register file. Based on the value of mode bit $\text{M, T}$ selects an input word to load in $\text{X. P}$ and $\text{Q}$ interface with the corresponding bits in the code word to choose the addressed word. Which one of the following represents the functionality of $\text{P, Q,}$ and $\text{T}?$

(A)

$\text{P}$ is $10:1$ multiplexer $; \qquad \; \;\text{Q}$ is $5:1$ multiplexer $; \qquad \; \text{T}$ is $2:1$ multiplexer

(B)

$\text{P}$ is $10:2^{10}$ decoder $; \qquad \quad \text{Q}$ is $5:2^{5}$ decoder $; \qquad \quad \text{T}$ is $2:1$ encoder

(C)

$\text{P}$ is $10:2^{10}$ decoder $; \qquad \quad \text{Q}$ is $5:2^{5}$ decoder $; \qquad \quad \text{T}$ is $2:1$ multiplexer

(D)

$\text{P}$ is $1:10$ de-multiplexer $; \quad \; \;\text{Q}$ is $1:5$ de-multiplexer $; \quad \text{T}$ is $2:1$ multiplexer