DNT231 DIGITAL SYSTEM
Laboratory Module
DNT 231
Digital System
Semester 1 2008/2009
LAB 5
MULTIPLEXER & DEMULTIPLEXER
MARKS
LECTURER
ASSOC PROF DR KENNETH SUDARAJ
DEMO:
PLV
MRS FARIDAH HASSAN
REPORT:
TECHNICIAN
MR BAZLI BAHADON
TOTAL:
Student’s Particular:
Name
Matrix No.
Programme
Group
Date of exp.
Received by
:______________
Date
:______________
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DNT231 DIGITAL SYSTEM
Laboratory Module
LAB 5: MULTIPLEXER & DEMULTIPLEXER
OBJECTIVES
1. To understand the operation of multiplexer and demultiplexer.
2. To design basic multiplexer and demultiplexer circuit
EQUIPMENTS/COMPONENTS




Logic gates ( 3 pcs 7408, 1 pc 7404, 1 pc 7432)
1 pc LED
6 pcs toggle switch
1 resistor 330
INTRODUCTION
A digital multiplexer (MUX) or data selector is a logic circuit that accepts several digital
data inputs and selects one of them at any given time to pass on to the output. Primarily
they are used for data routing which selects a transmission path for outgoing data
according to the coding criteria established by binary inputs. The routing of the desired
data input to the output is controlled by SELECT inputs (often referred to as ADDRESS
inputs). Figure 5.1(a) shows the functional diagram of a general digital multiplexer.
I0
I1
Output Z
I N-1
Select inputs
Figure 5.1(a) Functional diagram of digital multiplexer (MUX)
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Laboratory Module
A Multiplexer takes several inputs and transmits one of them to the output. A
demultiplexer performs the reverse operations. It takes a single input and distributes it
over several outputs. Figure 5.1(b) shows the functional diagram for digital demultiplexer
(DEMUX). The select inputs code determines to which output the DATA input will be
transmitted. In other words, the demultiplexer takes one input data sources and
selectively distributes it to 1 of N output channels just like multiposition switch.
O0
O1
Data
Input
O N-1
Select inputs
Figure 5.1 (b) General demultiplexer (DEMUX)
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PROCEDURE
1. Figure 5.2 shows the logic diagram of 4:1 MUX. Design the MUX by showing:
a) Truth Table
b) Boolean Expression
c) Circuit Diagram
4 to 1 MUX
I0
I1
Output
I2
I3
S1 S2
Selector
Figure 5.2 4:1 MUX
2. Construct the circuit for MUX that you have designed in procedure 1. Check the
operation of the circuit and compare the result with the truth table construct at
procedure 1.
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DNT231 DIGITAL SYSTEM
Name: ___________________________________
Laboratory Module
Matrix No. : ____________
RESULT
4:1 MUX
a)
b)
c)
Truth Table
Boolean Expression
Circuit Diagram
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DNT231 DIGITAL SYSTEM
Laboratory Module
Name: ___________________________________
Matrix No. : ____________
EXERCISE
1. Figure 5.3 shows the logic diagram of 1:4 DEMUX. Design the DEMUX by
showing:
a. Truth Table
b. Boolean Expression
c. Circuit Diagram
1 to 4 DEMUX
Y0
Y1
Input
Y2
Y3
S1 S2
Selector
Figure 5.3 1:4 DEMUX
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DNT231 DIGITAL SYSTEM
Name: ___________________________________
Laboratory Module
Matrix No. : ____________
Answer:
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DNT231 DIGITAL SYSTEM
Name: ___________________________________
Laboratory Module
Matrix No. : ____________
DISCUSSION
CONCLUSION
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