Digital Electronics and Logic Circuits (CSCT2202)
Computer Science - COS
Semester: Second Semester
Level: 200
Year: 2018
REPUBLIC OF CAMEROON THE UNIVERSITY OF BAMENDA
Peace-Work-Fatherland P. O Box 39 Bambili
School/Faculty: HTTTC Department: CS Lecturer(s): SP TCHASSO
Level:100 Semester: Academic Year:
Course Code: ENGL 4101 Course Title: DIGITAL ELECTRONICS AND LOGIC CIRCUITS
Date: /07/2018 Hall: Time: 1hr
Instructions: Answer all questions
Exercise 1
A logic circuit has 04 inputs: A, B, C, D and an output X. the output X is high only if C
and D are low while A or B or both are high. The input A is the most significant bit and
the input D the least significant bit.
1-
Draw the truth table of the system
2-
Find the output expression X
3-
Simplify X using Boolean algebra
4-
Fill the truth table in a karnaugh-map and find the new expression of X
5-
Draw the logic diagram of the logic expression of question 4
Exercise2
The figure 6.14 below shows the block diagram of an electronic circuit which
accepts two binary numbers of two bits X
1
X
0
and Y
1
Y
0
and gives at the output the
binary number Z
3
Z
2
Z
1
Z
0
which is equal to the arithmetic product of the two
input numbers. For the inputs, X
3
and Y
0
are the least significant bits (L-SB)
while fore the outputs, Z3 is the most significant bit (MSB) and Z
0
is the least
significant bit.
Figure 6.14: Multipiicator circuit.
www.schoolfaqs.net
a. What do you understand by the statements "Least Significant Bit" and “Most
Significant Bit"?
b. Establish the truth table of the system.
c. Write the expression of each of the outputs Z
3
, Z
2
, and Z
0
as function of X
1
, X
0
,
Y
1
and Y
0
.
d. Using k-maps, simplify the output equations obtained from above.
e. Draw the logic diagram of the electronic multiplicator circuit using the
simplified output equations from the k-maps:
www.schoolfaqs.net
