This document provides an overview of digital electronics and chapter 1 of the course on intro to digital systems. It includes details about the student's personal information and contact details, an outline of topics to be covered in chapter 1, and the content of chapter 1 which discusses numerical representation in digital and analog systems, the advantages and disadvantages of digital techniques, and how digital systems overcome the limitations of analog systems using ADCs and DACs. It provides examples of analog and digital systems and concludes with assigning a group work on describing TTL or CMOS technology.

1. DIGITAL ELECTRONICS
(BEL 20303)
Section 5 & 6

2. PERSONAL DETAILS
Name: Nur Ilyani Ramli
Room: Block C15, Room 17
Contact No: 013-4549494
Email: ilyani@uthm.edu.my

3. CHAPTER 1
INTRO TO DIGITAL
SYSTEM
1.
2.
3.
4.
5.
6.
Numerical Representation
Digital & Analog Systems
Advantages of Digital Techniques
Limitation of Digital Techniques
Overcoming the limitation of an analog world
TTL and CMOS technology (Assignment 1)

4. Learning Outcomes
At the end of this chapter, you must be able to:
1. Distinguish between analog & digital representations
2. State the advantages and disadvantages of digital
techniques compared with analog
3. Appreciate the need for ADCs and DACs
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5. 1. Numerical Representations
- Most naturally occurring physical quantities in our world are
analog in nature.
- Quantities are measured, monitored, recorded, manipulated
arithmetically, observed in most physical systems.
- Important when dealing with quantities
– To represent their values efficiently and accurately
– 2 ways to represent them:
1) ANALOG representation
2) DIGITAL representation
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6. Analog Representation
Represent a quantity by a continuously variable
Characteristic of analog quantities
– They vary over a continuous range of values
Example
– 1) Speedometer
– 2) Thermometer
Use a mechanical
means
⇒ In electrical mean, the measured/processed physical quantity is converted to
a proportional electrical signal (V or I) → used by the system for display,
processing or control purposes
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7. Digital Representation
Represent a quantity by a symbol, called digits.
Characteristic of digital quantities
– They varied in discrete steps
Example
1) Digital Clock
2) Digital weighting scale
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8. Digital Number Systems
There are many numbering systems used in digital
technology.
– Decimal ⇒ most familiar to us
– Binary
– Octal
– Hexadecimal
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9. 1.2 Digital & Analog Systems
ANALOG SYSTEM
Devices that manipulate physical quantities that are
represented in analog form.
Example: magnetic tape recording and playback
equipment
DIGITAL SYSTEM
Combination of devices designed to manipulate
logical information or physical quantities that are
represented in digital form.
Example: digital calculator
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10. Example 1: Tape
During playback, the ferromagnetic
material in the tape head is magnetized
as the magnetic tape passes.
Then, the magnetic field penetrates a coil
of wire which is wrapped around it.
Change in magnetic field will induce a
voltage in the coil according to
Faraday's law. This induced voltage
forms an electrical image of the signal
which is recorded on the tape.
Source: http://hyperphysics.phy-astr.gsu.edu/HBASE/Audio/tape.html#c4
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11. Example 2: Computer
All the stored and processed data are in binary form.
Why ?
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12. Example 3: CD
CD player: digital and analog parts co-exist together
(source: How Stuff Works website)
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13. 1.3 Advantages of Digital Techniques
1. Digital systems are easier to design
2. Information storage is easy
3. Accuracy & precision are easier to maintain
throughout the system
4. Operation can be programmed
5. Digital circuits are less affected by noise
6. Digital circuitry can be fabricated on IC chips
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14. 1.4 Disadvantages of Digital Techniques
1. The real world is analogue
2. Processing digitised signals takes time
3. Digital circuits use more energy than analogue
circuits & produce more heat
4. Digital circuits are made from analogue components
– must make sure the digital behaviour is not
affected by the analogue
5. Digital circuits are sometimes more expensive (in
small quantity)
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15. 1.5 Digital Systems Overcome the Drawback
of Analog Systems
When dealing with analogue inputs and outputs,
four steps must be followed
1. Convert the physical variable to an electrical signal
(analogue)
2. Convert the electrical (analogue) signal into digital
form ⇒ ADC (Analogue Digital Converter)
3. Process (operate on) the digital information
4. Convert the digital outputs back to real-world
analogue form ⇒ DAC (Digital Analogue
Converter)
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16. DIGITAL
Example: Block diagram for a digital temperature control system
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17. Reference
Thomas L. Floyd, Digital Fundamentals (10th edition),
Pearson, 2009
Ronald J. Tocci, Neal S. Widmer & Gregory L. Moss,
Digital Systems: Principles and Applications (11th
edition), Pearson, 2011
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18. Group Assignment 1
Prepare a one page work describing TTL or CMOS
Technology.
1- Explain current TTL/CMOS technology in general.
2- Advantage and disadvantage of TTL/CMOS.
3- Application.
Dateline: Tuesday, 17 September 2013
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