Question

We wish to design a decoder, with three inputs, x, y, z, and eight active high outputs, labeled 0, 1, 2, 3, 4, 5, 6, 7. There is no enable input required. (For example, if xyz = 011, then output 3 would be 1 and all other outputs would be 0.) The only building block is a two-input, four output decoder (with an active high enable).

Answer 1

Answer:

the only building block is a two-input, four output decoder (with an active highe enable). the truth table is shown:

EN A B 0 1 2 3

0 X X 0 0 0 0

1 0 0 1 0 0 0

1 0 1 0 1 0 0

1 1 0 0 0 1 0

1 1 1 0 0 0 1

A------        --------0

B------        --------1

                --------2

                --------3

Explanation: