Overview of digital communication in hsn, digital communication in multimedia and application, Overview of digital communication in high speeed networking, Overview of digital communication in hsn

1. OVERVIEW OF DIGITAL
COMMUNICATION
SATYA PRAKASH JOSHI

2. GUIDED MEDIA
• Guided Media Guided Transmission Media uses a cabling
system that guides the data signals along a specific path .
• The data signals are bound by the cabling system .
• Guided Media is also known as Bound Media or Wired media

3. TWISTED PAIR OVERVIEW
• A type of cable that consists of two
independently insulated wires twisted around
one another. It consist of two conductors, each
with it’s own plastic insulation.
• The use of two wires twisted together helps to
reduce crosstalk and electromagnetic induction.
• While twisted-pair cable is used by older
telephone networks and is the least expensive
type of local-area network (LAN) cable, most
networks contain some twisted-pair cabling at

4. SHIELDED TWISTED PAIR
• STP cable was first developed by IBM for Token Ring networks.
• It consists of two individual wires wrapped in a foil shielding
that helps provide more reliable data transmission.
• STP cable has metal foil or braided mesh covering that encases
each pair of insulated conductors.
• Although metal casing improves the quality of cable by
preventing the penetration of noise or crosstalk.

5. UNSHIELDED TWISTED PAIR
• UTP cable is a cable used in computer networking that consists
of two shielded wires twisted around each other.
• Most common twisted pair cable used in communication is
referred to as unshielded twisted pair (UTP).

6. COAXIAL CABLE
• Coaxial cable or coax carries signals of higher frequency ranges than
those in twisted pair cable.
• Coax has central core conductor of solid or stranded wire (usually
copper) enclosed in an insulating sheath.
• The outer metallic wrapping serves both as a shield against noise and
as the second conductor, which completes the circuit.
• This outer conductor is also enclosed in an insulating sheath and the
whole cable is protected by a plastic cover.

7. FIBER OPTICS
• A fiber-optic cable is made of glass or plastic and transmit
signals in the form of light.
• To understand the optical fiber, we first need to explore several
aspects of the nature of light.
• Light travels in a straight line as long as it is moving through a
single uniform substance.

8. UNGUIDED MEDIA
• Unguided media transport electromagnetic waves without using
a physical conductor.
• This type of communication is often referred to as wireless
communication.
• Signals are normally broadcast through free space and thus are
available to anyone who has a device capable of receiving them.

9. VSAT
• VSAT stands for very small aperture terminal (VSAT) is a two-
way satellite ground station.
• A VSAT consists of two parts, a transceivermthat is placed outdoors
in direct line of sight to the satellite and a device that is placed
indoors to interface the transceiver with the end
user's communications device, such as a PC.
• The transceiver receives or sends a signal to a satellite transponder
in the sky. The satellite sends and receives signals from a ground
station computer that acts as a hub for the system.
• Each end user is interconnected with the hub station via the satellite,
forming a star topology.

10. SATELLITE
• A communications satellite is an artificial satellite that relays
and amplifies through the use of a transponder, radio
telecommunications signals, between a source transmitter and
a receiver at different locations on Earth.

11. TRANSMISSION CHARACTERISTICS
• Attenuations
• Attenuations means a loss of energy.
• When a signal, simple or composite, travels through a medium, it loses
some of it’s energy in overcoming the resistance of the medium.
• That is why a wire carrying electric signals gets warm, if not hot, after a
while.
• Some of the electrical energy in the signal is converted to heat.

12. NOISE
• Noise is the another cause of impairment. Several types of
noise, such as thermal noise, crosstalk, and impulse noise, may
corrupt the signal.
• Noise may cause loss of data, may cause re-transmission of
data. Noise may corrupt the signal, or that may create extra
signal.

13. SIGNAL TO NOISE RATIO (SNR)
• SNR = average signal power/ average noise power
• SNR is actually the ratio of what is wanted (signal) ro what is
not wanted (noise).
• A high SNR means the signal is less corrupted by noise;
• Low SNR meant the signal is more corrupted by noise;

14. PROPAGATION DELAY
• Propagation delay measures the time required for a bit to travel
from the source to destination.
• The propagation delay is calculated by dividing the distance by
the propagation speed.
• PD = Distance / Propagation Speed