UGC NET CSE | June 2009 | Part 2 | Question: 05

Question

In order to implement a $\text{n}$ variable switching function, a $\text{MUX}$ must have :

• A. $2^{n}$ inputs
• B. $2^{n}+1$ inputs
• C. $2^{n-1}$ inputs
• D. $2^{n}-1$ inputs

Answer 1

Ans: A

Any n-variable logic function, in canonical sum-of minterms form can be implemented using a single 2^n -to-1 multiplexer.

Any n-variable logic function can be implemented using a smaller 2^(n-1)-to-1 multiplexer and a single inverter

ref: http://meseec.ce.rit.edu/eecc341-winter2001/341-1-15-2002.pdf

Answer 2

A n-variable function can be implemented by a mux with n-1 selection lines. Thus the MUX must have $2^{n-1}$ data inputs.

Answer C