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Title: Lesson 3 Data Representation and Digital Electronics
Description: This lecture note will cover about Data Representation and and the two types of signals. It will also include the concept of Digital Electronics like digital signal and the different types of coding systems in computers. This lecture note is very simple, concise and yet very informative.
Description: This lecture note will cover about Data Representation and and the two types of signals. It will also include the concept of Digital Electronics like digital signal and the different types of coding systems in computers. This lecture note is very simple, concise and yet very informative.
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Data Representation and Digital
Electronics
Objectives
• Define data representation
• Know how computers represent
numbers, words, and letters using
bits
• Differentiate bits from bytes
• Define digital electronics
• Define and know today’s
microprocessors
Data Representation
• Makes it possible to convert letters, sounds,
and images into electrical signals
• Signal
• Codified message
• Sequence of states in a communication channel
that encodes a message
Signal
• Two main types of signals
• Digital
• Data is made up of discrete
numbers, with each bit being
either a 1 or a 0 – it’s either
on or off, nowhere in
between
• Analog
• Data is made up of a
continuous wave of
information, with varying
degrees in between
Digital Electronics
Digital Electronics
• Bytes are used to represent one character – a
letter, number, or punctuation mark
• For example, the letter H is represented in binary
code as 01001000
• An exclamation point (!) is 001000001
Digital Electronics
• Digital vs
...
Analog
Digital Electronics
• How can a computer represent numbers,
characters, pictures and sounds using bits?
• Numeric Data
• Character Data
• Sounds and pictures
Digital Electronics
• Numeric Data
– Base 2
– The numbers that might be
used in arithmetic
operations
– The following table lists
some decimal numbers
and their binary
equivalent
– Encoded differently
Digital Electronics
• Character Data
– Consist of letters, symbols and numerals that
will not be used in arithmetic calculations
– A digital computer uses a series of bits to
represent letters, characters, and numerals
– 3 popular coding system
•
•
•
•
ASCII
Extended ASCII
EBCDIC
UNICODE
Digital Electronics
• ASCII
– Pronounced as “ASK ee”
– American Standard Code for Information
Interchange
– Requires only seven bits for each character
– For example, the ASCII code for uppercase M is
77
...
– Provides codes for 128 additional characters
Digital Electronics
• Extended ASCII
Digital Electronics
• EBCDIC
– Pronounced as “EB seh dick”
– Extended Binary Coded Decimal Interchange
Code
– An alternative 8-bit code usually used by IBM
mainframe computers
Digital Electronics
• UNICODE
• Unicode uses 16 bits
and provides codes for
65,000 characters – a
bonus for representing
alphabets of multiple
languages
– Used for foreign
language support
• “You ni code”
Digital Electronics
• Sounds and pictures
– Sounds and pictures must be transformed into a
format the computer can understand
– A computer must somehow digitize colors,
notes, and instrument sounds 1s and 0s, in order
to work sounds and pictures
...
– A red dot on your computer screen might be
represented by 110, a green dot by 0010
Digital Electronics
• File Header
– Data files have a file header
– Tells the computer how the binary code is used to
represent the data
– The header tells the computer if the binary code
represents a music file, a graphic, a text
document, etc
Digital Electronics
• When a computer works with a series of 1s
and 0s, how does it know which code to use
– All of the things that a computer works with is
stored in files as a long series of 1s and 0s
...
– Most computer files contain a file header with
information on the code that was used to represent
the file data, to avoid confusion
–
...
– An integrated circuit designed to process
instructions
– The most significant component of computer
and usually the most expensive single
component
...
– Introduced the world’s
first microprocessor, the
4004, during 1971
Companies produce most of today’s
popular microprocessors
• AMD (Advanced Micro
Devices)
– Intel’s chief rival in the
PC chip market
...
• A digital computer is a simpler technology
than an analog computer
...
Why are computers digital?
• Computers are digital because computer
designers have found it to be relatively
simple, dependable, and adaptable
technology
• A digital computer is a simpler technology
than an analog computer
• Most computers use the simplest type of
digital technology, their circuits have only
two possible states
How does a computer store and
transport all those bits?
• Bits take the form of electrical
pulses that can travel over
circuits
• The circuits, chips, and
mechanical components
forming a computer are
designed to work with bits
• These components are housed
within the computer’s system
unit
Questions?
Clarifications?
Title: Lesson 3 Data Representation and Digital Electronics
Description: This lecture note will cover about Data Representation and and the two types of signals. It will also include the concept of Digital Electronics like digital signal and the different types of coding systems in computers. This lecture note is very simple, concise and yet very informative.
Description: This lecture note will cover about Data Representation and and the two types of signals. It will also include the concept of Digital Electronics like digital signal and the different types of coding systems in computers. This lecture note is very simple, concise and yet very informative.