DATA COMMUNICATION Lecture15 Recap of Lecture 14 w

DATA COMMUNICATION Lecture-15

Recap of Lecture 14 w Introduction to the Encoding Techniques w Digital-To-Digital Encoding w Types of Digital-To-Digital Encoding w Uni. Polar Encoding w Polar Encoding – NRZ

Overview of Lecture 15 w Types of Digital-To-Digital Encoding w Polar Encoding – Return to Zero (RZ) Encoding – Biphase Encoding w Bipolar Encoding

Conversion Methods

Types of Digital-to-Digital Encoding Digital/Digital Encoding Unipolar Polar Bipolar

Types of Polar Encoding

Return to Zero (RZ)

Biphase Encoding w Best existing solution to the problem of Synchronization w Signal changes at the middle of bit interval but does not stop at zero

Biphase Encoding Manchester Differential Manchester

Manchester

Differential Manchester

Bipolar Encoding w Like RZ, it uses three voltage levels: w Unlike RZ, zero level is used to represent binary 0 w Binary 1’s are represented by alternate positive and negative voltages

Bipolar Encoding

Alternate Mark Inversion (AMI) w Simplest type of Bipolar Encoding w Mark Comes from Telegraphy (1) w Alternate Mark Inversion means Alternate ‘ 1’ Inversion

Alternate Mark Inversion (AMI)

Bipolar 8 Zeros Substitution (B 8 ZS)

High Density Bipolar 3 (HDB 3)

Summary w Types of Digital-To-Digital Encoding w Polar Encoding – Return to Zero (RZ) Encoding – Biphase Encoding w Bipolar Encoding

Suggested Reading w Section 5. 1, “Data Communications and Networking” 2 nd Edition by Behrouz A. Forouzan