1. DATA COMMUNICATION
Lecture-14

2. Recap of Lecture 13 Signals Analog and Digital Data & Signals
Periodic & Aperiodic Signals
Sine Waves and its Characteristics
Time and Frequency Domain
Frequency Spectrum and Bandwidth
Other Definitions of Bandwidth
Digital Signals

3. Overview of Lecture 14 Introduction to the Encoding Techniques
Digital-To-Digital Encoding
Types of Digital-To-Digital Encoding

4. Introduction
Information must be transformed into signals before it can be transformed across the communication media
How this information is transformed depends upon its original format and on the format of the communication hardware

5. Conversion Methods
One by one the boxes will be formed take care of the sequence (start from left) (digital/digital)

6. Digital-to-Digital Conversion
Digital-to-Digital conversion/encoding is the representation of digital information by digital signal
For Example:
When you transmit data from Computer to the Printer, both original and transmitted data have to be digital

7. Digital-to-Digital Conversion
First of all the the first block the middle blue box and the third box without signal will be shown and there will be no arrows then 1) first block that contains will blink(this box should be colored) and the first arrow will be shown (arrow in red color)……….Second the middle box which is in the figure in blue color will blink four times (You can change the color of the box as u like)and then the second arrow tht is after the blue box in the figure will be shown (remember this is only one arrow that is animated so as the second arrow is shown the first arrow will vanish ……………then at the most right hand side the signal will be shown animated……………when the second arrow will vanish as soon as the signal starts coming(we will show the formation of the signal)……………the speed of the animations should be slow in this case

8. Types of Digital-to-Digital Encoding
Digital/Digital Encoding
Unipolar
Polar
Bipolar
One by one the boxes will be formed (take care of the sequence)

9. Unipolar Encoding Simple and Primitive Almost Obsolete Today
Study provides introduction to concepts and problems involved with more complex encoding systems

10. Unipolar Encoding
The first scene will show all the things except the red signal ……………..the red signal will be animated ( we will show its formation) ……….the animation should be slow

11. Pros and Cons of Unipolar Encoding
Straight Forward and Simple
Inexpensive to Implement
CONS
DC Component
Synchronization

12. Synchronization Example
Bit Rate = 1000 bps
1000 bits second
1 bit = sec
Positive voltage of sec means five 1’s
Sometimes it stretches to seconds and an extra 1 bit is read by the Receiver

13. Polar Encoding Polar encoding uses two voltage levels
One positive and one negative
Average voltage level on the line is reduced
DC Component problem of Unipolar encoding is alleviated

14. Types of Polar Encoding
One by one the boxes will be formed( take care of the sequence)

15. Non Return to Zero (NRZ)
The level of signal is either positive or negative
NRZ
NRZ-L
NRZ-I

16. Non Return to Zero-Level (NRZ-L)
Now the first scene will show all the figure without the signals tht are in red color…………..second the first signal (above signal) will be animated (we will show its formation) ………..then when the first signal completes its formation then the second signal will come(we will show its animation)………….the most impotant is that the text (NRZ-L) and (NRZ-I) should be in Box with prominent color

17. Non Return to Zero-Invert (NRZ-I)

18. Summary Introduction to the Encoding Techniques
Digital-To-Digital Encoding
Types of Digital-To-Digital Encoding
UniPolar Encoding
Polar Encoding
NRZ

19. Suggested Reading
Section 5.1, “Data Communications and Networking” 2nd Edition by Behrouz A. Forouzan

20. DATA COMMUNICATION
Lecture-14