# need help with outputs for a truth table

Discussion in 'Homework Help' started by micachu, Nov 2, 2014.

1. ### micachu Thread Starter New Member

Oct 13, 2014
15
0
Hi I'm given the following expressions
Ja = X(Qb)+Y'(Qb)'
Jb = XQa'
Ka = XY'(Qb)'
Kb = XY' + Qa
Z = XY(Qa) + X'Y'(Qb)
and suppose to find state equations

I started by making the truth table shown below

I'm not sure if I'm doing the outputs correctly for Qa+1 and Qb+1. The way I did the output Qa+1 was I looked at Ja Ka and Qa. For example if Ja Ka Qa is 101, according to the JK truth table that's suppose to be a set, so I placed a 1 on the output of Qa+1. But since I have X and Y as inputs, do I have to look at those as well?

Thanks in advance. Will appreciate any help.

2. ### WBahn Moderator

Mar 31, 2012
18,079
4,917
It sounds like you are on the right track. The output of Qa is dependent only on Ja, Ka, and Qa (as is the case with any JKFF). Your state equations, on the other hand, will be in terms of X, Y, Qa, and Qb since those define the system's state and inputs.