MultiplexerMultiplexerDemultiplexerDemultiplexer

Lecture 10

Course Conducted by –Shuvodip Das,

Lecturer, ETE Dept.Prime University, Bangladesh.

Course Conducted by –Shuvodip Das,

Lecturer, ETE Dept.Prime University, Bangladesh.

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What is a Multiplexer (MUX)?

• A MUX is a digital switch that has multiple inputs (sources) and a single output (destination).

• The select lines determine which input is connected to the output.

• MUX Types 2-to-1 (1 select line)

4-to-1 (2 select lines)

8-to-1 (3 select lines)

16-to-1 (4 select lines)

2

Multiplexer Block Diagram

SelectLines

Inputs(sources)

Output(destination)

12N

N

MU

X

MULTIPLEXER ( DATA SELECTOR)- circuit that can select one of a number of inputs and pass the logic level of that input to the output.

BASIC TWO-INPUT MULTIPLEXERBASIC TWO-INPUT MULTIPLEXER

DATAINPUTS

I1

I0

SSELECT INPUT

SISIZ 10

3

FOUR-INPUT MULTIPLEXERFOUR-INPUT MULTIPLEXER

S0S1

I0

I1

I2

I3

4

8-to-1 Multiplexer8-to-1 Multiplexer

5

MULTIPLEXER LOGIC DIAGRAMMULTIPLEXER LOGIC DIAGRAM

I 0

I 1

I 2

I 3

I 4

I 5

I 6

I 7

ES 2 S 1 S 0

74151

MUX

DATA

INPUTS

SELECT LINES

Z_Z

6

Typical Application of a MUX

7

MP3 PlayerDocking Station

Laptop Sound Card

DigitalSatellite

DigitalCable TV

Surround Sound System

MU X

D0

D1

D2

D3

Y

B A Selected Source

0 0 MP3

0 1 Laptop

1 0 Satellite

1 1 Cable TV

Multiple Sources

Single Destination

Selector

MULTIPLEXER APPLICATIONSMULTIPLEXER APPLICATIONS

•DATA ROUTING

•PARALLEL-TO-SERIAL CONVERSION

•OPERATION SEQUENCING

•IMPLEMENT LOGIC FUNCTION OF A TRUTH TABLE

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What is a Demultiplexer (DEMUX)?• A DEMUX is a digital switch

with a single input (source) and a multiple outputs (destinations).

• The select lines determine which output the input is connected to.

• DEMUX Types 1-to-2 (1 select line)

1-to-4 (2 select lines)

1-to-8 (3 select lines)

1-to-16 (4 select lines)

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Demultiplexer Block Diagram

SelectLines

Input(source)

Outputs(destinations)

2N1

N

DE

MU

X

DEMULTIPLEXER ( DATA DISTRIBUTOR)- circuit that depending on the status of its select inputs will channel its data input to one of several outputs.

1:2 Demultiplexer

• Here the 1:2 DEMUX has 2 O/P lines Y0 and Y1 and one select (control) line S0

• When S0 =0 then output= Y0

• When S0 =1 then output= Y1

Circuit Diag.

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Inputs Output

S1 S0

0 0 Y0=D

0 1 Y1=D

1 0 Y2=D

1 1 Y3=D

Circuit diagram and truth table of 1:4 DEMUX are shown below:

1:4 Demultiplexer

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1-of-8 DEMULTIPLEXER1-of-8 DEMULTIPLEXER

12

DEMULTIPLEXER LOGIC DIAGRAMDEMULTIPLEXER LOGIC DIAGRAM•Logic circuit that depending on the status of its select inputs will funnel its data input to one of several data outputs.

•Separate enable inputs (useful for cascading decoders) into AND gate which must be high to enable the decoder outputs.

A 2 A 1 A 0

74138DEMUX

1-OF-8 DECODER

SELECT LINES

E

1E2E

3E

0O

1O

2O

3O

4O

5O

6O

7O

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Typical Application of a DEMUX

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Single Source Multiple Destinations

Selector

D0

D1

D2

D3

X

DE

MU

X

B A Selected Destination

0 0 B/W Laser Printer

0 1 Fax Machine

1 0 Color Inkjet Printer

1 1 Pen Plotter

B/W LaserPrinter

Color InkjetPrinter

PenPlotter

FaxMachine

Applications of Demultiplexer

Application areas: 1.Telegraphy2.Telephony3. Video processing4. Digital broadcasting5. Analog broadcasting

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