Chapter B, Problem 39E

Explanation of Solution

3-bit Counter using three D flip-flops:

Explanation:

The above block diagram describes about the 3-bit counter using D-flip flops. If x=o then, the counter must be multiplied by even numbers and the count will be increased. If x=1 then, the counter must be multiplied by odd numbers and the count will be decreased.

Truth table:

...

x	Current state	Next State	Dff 1	Dff 2	Dff 3
0	000	010	0	1	0
0	010	100	1	0	0
0	100	110	1	1	0
0	110	000	0	0	0
1	111	101	1	0	1