# Function realisation using MUX,DEC and

#### xxxyyy

Joined Oct 7, 2011
34
Problem:
Realise function F(A,B,C,D)= A*C*D + A*B*D + A*C*D + A*B*D using DEC 3/8, MUX 8/1 and required number of Nor gates. (underlined variables are complements)
I know how to realise it using only MUX 8/1,but I really have no idea how to use MUX in combination with DEC and NOR to realise function above... Can someone help me?

Last edited:

#### Yako

Joined Nov 24, 2011
245
I could use some help with this one too.

#### Yako

Joined Nov 24, 2011
245
When you formally study digital electronics you are told things like: with an OR any 1 gives a 1, and with a NOR -- any 1 gives a 0.

#### xxxyyy

Joined Oct 7, 2011
34
I'm not really sure that I understood you well,but never mind

#### Georacer

Joined Nov 25, 2009
5,182
Supposing that you can use the NOR gates to implement a SoP form with the DeMUX and you have two DeMUXs, consider the following:

Separate the function into two parts, the one that factorizes with A and the other with A'. Construct each sub-function with a DeMUX. Use the MUX with selector A to select between the outputs of the two functions. A 2/1 MUX would be sufficient here.

Check if that's ok and come back to tell us.