# Design a 4-bit majority function.

Discussion in 'Homework Help' started by surenboy, Oct 4, 2011.

1. ### surenboy Thread Starter New Member

Oct 4, 2011
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0
A majority function is a system that will assert when there are more 1s than 0s on the inputs. Design a 4-bit majority function.
hey guys anyone please explain how to solve this. please explain it after done.thank you.

2. ### BillO Well-Known Member

Nov 24, 2008
985
136
You mean do your homework for you?

First, a couple of questions. Do you need a logic statement or a logic circuit? Or can you do this with an analogue circuit?

Now, lets try to understand where you are having difficulty. Try to do this:

If you have 4 bits named A, B, C, D, can you name for me the 4 ways you can have a majority?

Last edited: Oct 4, 2011
3. ### Georacer Moderator

Nov 25, 2009
5,142
1,266
The Homework Help section asks that you post up the work you have done so we can see it and find where you went wrong, or suggest better approaches. We will not do all your work for you, no matter how little time is left before it must be submitted.

Thank you.

4. ### surenboy Thread Starter New Member

Oct 4, 2011
3
0
hi,
A majority function is a system that will assert when there are more 1’s than 0’s on the inputs. Design a 4-bit majority function of "1".

sorry for inconvenient, this question have to be designed using digital circuit. it is my lab exercise.i don't understand what they are actually asking to do.

if there is any idea to designed this circuit,please provide it. thank you

Last edited: Oct 4, 2011
5. ### Georacer Moderator

Nov 25, 2009
5,142
1,266
You need to design a Boolean function in order to achieve your goal. Your function will have four inputs - the bits for comparison - and one output, that will say "yes" or "no".

With a 4-bit input, it is reasonable to tackle the problem by making its truth table (16 lines) and then proceeding with a Karnaugh map.

6. ### BillO Well-Known Member

Nov 24, 2008
985
136
@ Surenboy,

If you have 4 bits named A, B, C, D, can you name for me the 4 ways you can have a majority?

For example, Bob, Ted and Mary want to get something to eat. They decide that they will vote for pizza. The majority verdict will decide the vote. They realize there are 3 ways to get a clear majority. So they write down the following:

Pizza = Bob and Ted or Ted and Mary or Bob and Mary.

7. ### Markd77 Senior Member

Sep 7, 2009
2,803
594
I think there are 5 ways to have a majority.
<ed>Maybe the 5th way is unanimous, not a majority.</ed>

Last edited: Oct 4, 2011
8. ### BillO Well-Known Member

Nov 24, 2008
985
136
You are right, of course, but the unanimous situation will not need separate consideration. Done right, you only need to detect the majorities.

9. ### surenboy Thread Starter New Member

Oct 4, 2011
3
0
hi i get your point. from the truth table it shows 5 majority.
that is : A'BCD , AB'CD, ABC'D , ABCD' and ABCD.
your question helped me. thank you.