The document focuses on digital design, specifically multiplexers (mux) and demultiplexers (demux), detailing their real-life applications and functions. It includes problem-solving exercises involving basic logic gates, waveforms, and Karnaugh maps (k-maps) to reinforce understanding. The content is structured as part of a 2020 educational session, aiming to enhance practical knowledge in digital design.

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Session 14: Focus
 Multiplexers (MUX)
◦ Usage in Real-life Applications
 Demultiplexer (DEMUX)
◦ 1-to-4-line Demultiplexer
◦ Symbols or Representation
◦ Usage in Real-life Applications
 Solving problems
◦ With Basic Gates
 Solving Logical problems
 Home work problems
◦ Logic Gates
◦ K-maps

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Multiplexer (MUX)

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Multiplexer: Real-life Applications - 1
 Time Division Multiplexer (TDM) is one of the types of
multiplexers which join data streams by allotting every
stream a different time slot, in a sequence.

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Multiplexer: Real-life Applications - 2
 Choosing one input from multiple input lines, to be
given to Arithmetic Logic Unit (ALU)
Selector
Inputs Output Lines
Bringing out
One of the
Input values

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Demultiplexer (DEMUX)

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Demultiplexer (DEMUX)
 A demultiplexer
(DEMUX) basically
reverses the multiplexing
function
 It takes digital
information from one
line and distributes it to
one of the output lines
 Based on the data-select
inputs
 For this reason, it is also
known as data
distributor
3 Select Lines
8 Output
Lines

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1-to-4 line Demultiplexer
 For example, if the data select lines are (S1S0 - 10b) then data
input will be sent out through D2 output line

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Quiz 1: Draw the Output Waveforms
 Given data-input and data-select waveforms, draw the output
waveforms on D0 to D3

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DEMUX: Symbol or Representations

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Demux : Application
One of the Paths (A/B/C/D) is chosen,
to get different amplification of input signal
A: OpAmp:
Operational Amplifier

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Solving Problems with Basic Gates

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Problem 1: Draw the output waveform

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Problem 2: Draw the output waveform

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Problem 3: Draw the output waveform
This is a 4-input NAND Gate, operating as negative OR. Use DeMorgon’s Theorem
 What is the equivalent logic gate? 4-input NAND

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Problem 4: Draw the output waveform
This is a 4-input NOR Gate, operating as negative AND. Use DeMorgon’s Theorem.
 What is the equivalent logic gate? 4-input NOR

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Problem 5: Draw the output waveform

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Problem 6: Draw the output waveforms
XNOR Gate
XOR Gate

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Solving Some Logical Problems

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Problem 7: When does the alarm sound?
 The alarm sounds when any one of the three doors are opened.

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Problem 8: When does the alarm sound?
 Below is the circuit of car seat belt alarm system.
 When will the alarm sound?
 The alarm will sound if the seat belt is not buckled within 30 seconds of
switching ON the ignition !!!
Delay
Initially LOW. when Ignition is
ON, it becomes HIGH After 30
seconds of delay

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Problem 9: Staircase Two-way Switch
How does it work?

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Home Work Problems

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HW 1: Draw the output waveform

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HW 2: Draw the output waveform

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HW 3: Draw the output waveform

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HW 4: Draw the output waveform

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Solving Problems
with
K-maps

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HW 5: Group 1s in each of the K-maps

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HW 6: Group the 1s the K-map

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HW 7: Find the SOP terms

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HW 8: Find the SOP terms

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HW 9: Map to K-map from Truth table
What is the simplified expression in sum-of-products form? AB

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HW 10: Find the POS terms

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HW 11: Find the SOP & POS terms
A
AC
SOP:
POS:

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HW 12: Group the 1s in the K-map

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HW 13: Find the product terms

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HW 14: Simplify using 5-variable K-map

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Session 14: Summary
 Multiplexers (MUX)
◦ Usage in Real-life Applications
 Demultiplexer (DEMUX)
◦ 1-to-4-line Demultiplexer
◦ Symbols or Representation
◦ Usage in Real-life Applications
 Solving problems
◦ With Basic Gates
 Solving Logical problems
 Home work problems
◦ Logic Gates
◦ K-maps

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References
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