BCA Semester 1 – Digital Logic – Unit 5 Sequential Logic Design

Design MOD-7 counter with state and timing diagram.

Distinguish between sequential and combinational logic with example? Discuss the design procedure of combinational logic.

A sequential circuit with two D flip flops, A and B, two inputs x and y, and one output z, is specified by the following next state and output equations.$A(t + 1) = x'y + xAB(t + 1) = x/B + xAz = B.$

1. Draw the logic diagram.
2. Derive the state

Write short Notes on (any Two):

a) Parallel Adder

b) PLA

c) State Diagram

Differentiate between asynchronous and synchronous sequential circuits with example. Draw a block diagram, truth table and timing diagram to store 2001 in 4-bit SIPO register.

Define counter. Write a procedure to design a counter circuit. Design MOD-8 up counter.

Differentiate between synchronous and asynchronous counter. Design 3-bit up ripple counter.

What is counter? Design a mod 7 synchronous counter with state table, state diagram, circuit diagram.

Differentiate between synchronous and ripple counter. Design mod 7 ripple counter with its state diagram, sequence table, logic diagram and timing diagram.

What is state diagram? A sequential circuit with two D flip-flops A and B, one input x and one output z is specified by the following next state and output equations:

$A(t + 1) = A' + B, B(t + 1) = B' x, z = A + B'$

i) Draw the logic diagram of the circuit ii) Draw the state table iii) Draw the state diagram

Explain ring counter. Design a 3-bit asynchronous up counter with block diagram, count sequence table, and timing diagram.

Explain the design procedure of a clocked sequential circuit. Design a clocked sequential circuit whose state diagram is given in the figure.

Write short notes on (any two):

a) State reduction table 
b) Multiplexer
c) Synchronous and Asynchronous counter

Explain shift register with parallel load. Design a synchronous Mod-10 counter to count in the sequence 0,2,4,5,6,8 using T flip-flops.