Cable television systems originated in the 1940s to provide broadcast signals to areas without reception. A cable television system uses coaxial cable to transmit signals from an antenna site to a headend facility where the signals are processed and distributed through a network of trunk and feeder cables to subscriber drops that connect to homes. Modern cable systems are two-way and provide additional services like high-speed internet, digital cable TV, and phone through a hybrid fiber-coaxial network.

1. SEMINAR REPORT
On
“Cable Television System”
Prepared By
ABHISHEK SHARMA
(Enrollment No. : 110050111011)
6th
SEM (EC- 1 )
Guided By
Prof. VINIT PARMAR
Assistant Professor
E&C Dept., BIT
Department
Of
Electronics and Communication Engineering
Babaria Institute of Technology
Vadodara-Mumbai National Highway-8(NH-8)
Varnama, Vadodara-392140, Gujarat, India.

2. CABLE TELEVISION SYSTEM
 Cable television (TV) first began in Pennsylvania in 1948.
 Cable television also refer as COMMNITY ANTENA TELEVISION- CATV.
 This started to provide signals in that area were in shadow region or those
who did not receive signals from broadcast station.
 The “cable” in cable system refers to the coaxial cable that carries radio
frequency (RF) signals across the network. Coaxial cable is the primary
medium used to build cable TV systems.
 A typical cable operator now uses a satellite dish to gather TV signals. Early
systems were one-way with cascading amplifiers placed in series along the
network to compensate for signal loss. Taps were used to couple video signals
from the main trunks to subscriber homes via drop cables.
 A typical cable operator now uses a satellite dish to gather TV signals. Early
systems were one-way with cascading amplifiers placed in series along the
network to compensate for signal loss. Taps were used to couple video signals
from the main trunks to subscriber homes via drop cables.
 Broadband: Broadband transmission methods send multiple pieces of data
simultaneously to increase the effective rate of transmission. In cable
systems, broadband refers to the frequency-division multiplexing (FDM) of
many signals in a wide RF bandwidth over a hybrid fiber-coaxial (HFC)
network and the capability to handle vast amounts of information.
 Coaxial cable : Coaxial cable transports RF signals and has certain physical
properties that define the attenuation of the signal. These properties include
cable diameter, dielectric construction, ambient temperature, and operating
frequency. It consists of a center conductor surrounded by insulation and an
outside ground shield of braided wire. The shield is designed to minimize
electrical and RF interference.
 Tap: A tap divides the input signal RF power to support multiple outputs.
Typically, the cable operators deploy taps with two, four, or eight ports called
subscriber drop connections.
 Amplifier : An amplifier magnifies an input signal and produces a
significantly larger output signal.

3.  Hybrid fiber-coaxial (HFC): HFC is a mixed optical-coaxial network in
which optical fiber replaces the lower bandwidth coaxial where useful in the
traditional trunk portion of the cable network.
 Downstream : This is the direction of an RF signal transmission (TV
channels and data) from the source (headend) to the destination
(subscribers). Transmission from source to destination is called the forward
path.
 Upstream: This is the direction of an RF signal transmission opposite to
downstream: from subscribers to the headend, or the return or reverse path.
 There are five major components of a modern cable system:
 Antenna site: The location of an antenna site is chosen for optimum
reception of over-the-air, satellite, and sometimes point-to-point signals. The
main receiving antennas and satellite dishes are located at the antenna site.

4.  Headend: The headend is a master facility where signals are first received,
processed, formatted, and then distributed downstream to the cable network:
the transportation and distribution network. The headend facility is usually
unmanned, under security fencing, and is similar to a telephone company
central office.
 Transportation network: A transportation network links a remote
antenna site to a headend or a remote headend to the distribution network.
The transportation network can be microwave, coaxial supertrunk, or fiber-
optic.
 Distribution network: In a classic cable system called a tree-and-branch
cable system, the distribution network consists of trunk and feeder cables.
The trunk is the backbone that distributes signals throughout the community
service area to the feeder and typically uses 0.750-inch (19-mm) diameter
coaxial cable. The feeder branches flow from a trunk and reach all of the
subscribers in the service area via coaxial cables. The feeder cable is usually a
0.50-inch (13-mm) diameter coaxial cable.
 Subscriber drop: A subscriber drop connects the subscriber to the cable
services. The subscriber drop is a connection between the feeder part of a
distribution network and the subscriber terminal device (for example, TV set,
videocassette recorder [VCR], High Definition TV set-top box, or cable
modem). A subscriber drop consists of radio grade (RG) coaxial cabling
(usually 59-series or 6-series coaxial cable), grounding and attachment
hardware, passive devices, and a set-top box.
 Modern cable systems provide two-way communication between
subscribers and the cable operator. Cable operators now offer customers
advanced telecommunications services including high-speed Internet access,
digital cable television, and residential telephone service.