report about the digital system and logic design

1. Choman technical Institute
IT-Department
First Stage
Computer Organization and Logic Design
Lecture 1
Introduction to Digital Systems
Lecturer: Nergz Star Mohammed
Email: nsm170h@cs.soran.edu.iq

2. 1
Digital Concept
The term digital is derived from the Way computers perform operations, by
counting digits.
Digital technology is applied in a wide range of areas in addition to computers.
Such applications
television,
communications systems, radar, navigation and guidance systems,
military systems,
medical instrumentation.

3. Digital and Analog Quantities

4. Digital and Analog Quantities
Types of electronic devices or instruments:
Analog
Digital
Combination analog and digital
Analog
 An Analog Electronic System
Public Address System used to amplify sound so that it can be heard by large
audience.

6. Digital
 A computer performs operations Digitally.
Analog and Digital
 A System Using Digital and Analog Methods

7. Binary Digits
The conventional numbering system uses ten digits:
0,1,2,3,4,5,6,7,8, and 9.
The binary numbering system uses just two digits: 0 and 1.

8. Binary Digits
 The two binary digits are designated 0 and 1
 They can also be called LOW and HIGH, where LOW = 0 and HIGH = 1

9. Binary Digits v.s. Logic Levels
Binary values are also represented by voltage levels
Logic Levels
Major parts of a digital pulse

10.  Base line
 Amplitude
 Rise time (tr)
 Pulse width (tw)
 Fall time (tf)
Logic Levels
tw = pulse width
 T = period of the waveform
 f = frequency of the waveform

11. Duty Cycle of a Binary Waveform

12. The duty cycle off a binary waveform ibis defined as:

13. Basic Logic Operations

14. Not Operation [Inverter]
When the input is LOW, the output is HIGH
When the input is HIGH, the output is LOW
The output logic level is always opposite the input logic level.
AND Operation
When any input is LOW, the output is LOW

15. When both inputs are HIGH, the output is HIGH
OR Operation
When any input is HIGH, the output is HIGH
When both inputs are LOW, the output is LOW

17. Truth Table