A $4$ to $2$ priority encoder has four inputs Y$3,$ Y$2,$ Y$1$ & Y$0$ and two outputs A$1$ & A$0.$ The

input Y$3$ has the highest priority, whereas the input, Y$0$ has the lowest priority. In this case,

even if more than one input is $1$ at the same time, the output will be the binary code

corresponding to the input, which is having higher priority. $(25$ pts$)$

We will consider one more

output, V

in order to know, whether the code available at outputs

is valid or not.