Barani Institute of Management Sciences
Final-Term Exam Spring Semester 2020
Course Title : Digital Logic Design (Theory) Course Code : CS – 430
Discipline /Program : BS CS Total Marks : 30
Time allowed : 48 Hours Instructor’s Name(s): Noman Al Hassan
Instructions: Solve the paper on given template instead of creating your own or plank sheets.
Don’t change the credentials that are already filled by teacher.
Question 01: (6 Points)
Consider the combinational circuit as shown below
(a) Derive the Boolean expressions for T4.
(b) Evaluate the outputs F1 and F2 as a function of the four inputs.
(c) List the truth table with 16 binary combinations of the four input variables. Then list the binary values
for T4 and outputs F1 and F2 in the table.
(d) Plot the output Boolean functions obtained in part (c) on k- maps and show that the simplified
Boolean expressions are equivalent to the ones obtained in part (a) and (b).
Question 02: (6 Points)
Design a four‐bit shift register with parallel load using D flip‐flops. There are two control inputs: shift
and load. When shift = 1, the content of the register is shifted by one position. New data are transferred
into the register when load = 1 and shift = 0. If both control inputs are equal to 0, the content of the
register does not change.
Question 03: (6 Points)
The contents of a four-bit register are initially 1001. The register is shifted ten times to the right with
serial input being 110100101101 and then eight time left. What are the contents of the register at last
shift?
