Consider a $2-$by$-2$ switch. It has two input data ports, x$(0)$ and x$($l$),$ and a $2-$bit

control signal, ctrl$.$ The input data are routed to output ports y $(0)$ and y $($I according

to the ctrl signal. The function table is specified below.

$96$ CONCURRENT SIGNAL ASSIGNMENT STATEMENTS OF VHDL

Input Output Function

ctrl yl y$0$

$00$ xi x$0$ pass

$01$ x$0$ xi cross

$10$ x$0$ x$0$ broadcast x$0$

$11$ xi xi broadcast xi

$($a$)$ Use concurrent signal assignment statements to derive the circuit.

$($b$)$ Draw the conceptual diagram.

$($c$)$ Expand it into gate$-$level circuit and derive the simplified logic expression in

sum$-$of$-$products format.