1. Two bit counter

1. Two bit counter :
X
0
0
0
0
1
1
1
1
Q1
0
0
1
1
0
0
1
1
Q0
0
1
0
1
0
1
0
1
Q'1
0
0
1
1
0
1
1
0
Q'0
0
1
0
1
1
0
1
0
D1
0
0
1
1
0
1
1
0
D0
0
1
0
1
1
0
1
0
2 . Three bit counter :
X
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Q2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Q1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
Q0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Q'2
0
1
1
1
1
1
1
X
1
0
0
1
1
1
1
X
Q'1
0
0
0
0
0
1
0
X
0
1
1
0
0
0
1
X
Q'0
1
0
0
1
0
0
0
X
0
0
1
0
0
0
1
X
D2
0
1
1
1
1
1
1
X
1
0
0
1
1
1
1
X
D1
0
0
0
0
0
1
0
X
0
1
1
0
0
0
1
X
D0
1
0
0
1
0
0
0
X
0
0
1
0
0
0
1
X