Categories

# Q: Design custom ripple counter

Q- Design the ripple counter whose output sequence is represented by the following state diagram.

Ans: As it is a 3-bit counter hence we firstly arrange 3 FFs and now we design the combinational circuit to reset the counter at appropriate point.

Q2         Q1          Q0                          OUTPUT

0              0              0                              0

0              0              1                              1

0              1              0                              1

0              1              1                              1

1              0              0                              1

1              0              1                              1

1              1              0                              1

1              1              1                              0

And using K-map we get the combinational circuit as:

And the equation we get is

Z= Q2. (Q1 bar) + Q0. (Q1bar)

+ Q1. (Q0bar)

= Q2. (Q1 bar) + XOR (Q1, Q0)

OR

We can also have the equation as

Z= Q0. (Q1 bar) + Q1. (Q2bar)

+ Q2. (Q0bar)

And hence can have two types of combinational circuits to achieve the above counter. And the whole circuit with first combinational circuit as: 