1. If you apply DeMorgan's theorem to the expression of Y above , which answer do you get? (a, b, c, or d)

2. Which single two-input gate is equivalent to thecircuit of the figure above? A. AND B. OR C. NAND D. XNOR E. XOR

3. A Code-Word generator is to be designed. It uses four binary inputs, ABCD, and one output f. The circuit works as follows: there are only six valid input code words. Each valid code word consists of four-bits words (ABCD) that always contain two 0 and two 1, not necessarily in order, for instance ABCD = 0101 and ABCD = 1100 are valid code words. The output f will be 1 if the input is a valid code word that corresponds to an even number (using ABCD as binary number with A the most significant digit and D the less significant digit) and 0 if the input is a validinput code that corresponds to a odd number. For instance the code word 1010 will be interpreted as the number ten (an even number) and therefore the output f will be 1. Observe that a combination such as ABCD ="1000" (contain three equal inputs) is not valid and it will never occur.

The expression for the function f is: A. f = ?m(2,4,6,8,10,12,14,15) B. f = ?m(8,9,10,11,12,13,14,15) + d(0,1,2,3,4,5,6,7) C. f = ?m(6,10,12) + d(0,1,2,4,7,8, 11,13,14,15) D. None of the above

Y=AB(C + BD) Options: a)Y=A+B+CBD b) =A+B+CB+D c) Y = AB + C(B + D))