DTH is a new technology and it has matured to its full potential in other parts of the world. There are many application has been found every day for exploitation of benefits of DTH? The word ‘DTH’ is synonymous with transmission of digital video channel to home subscriber’s using a small dish antenna. The DTH utilizes a technology which enables a home to receive high speed internet broadband access data communication, voice over internet protocol (IP) telephony and much more using an open standard Digital Video Broadcasting (DVB) technology. The video channels are received with a suitable set top box. It is Capable of demodulating Motion Picture Engineering Group (MPEG-2) standard videos. It is for the return channel required for other services such as voice over internet protocol and broadband access data communications, that a return channel is also required for the home terminal. The return channel via the satellite is called RCS and is an open standard. Hardware compatible with DVB-RCS technology are readily available in the market in both Ku-band and C-band. DVB-RCS is an international open standard for multimedia satellite network where the return data rates in access of 2 Mbps are possible using low cost user terminals. The forward ink is usually at 40 Mbps. Today, most satellite TV customers in developed television markets get their programming through a direct broadcast satellite (DBS) provider, such as DISH TV or DTH platform. The provider selects programs and broadcasts them to subscribers as a set package. Basically, the provider’s goal is to bring dozens or even hundreds of channels to the customer’s television in a form that approximates the competition from Cable TV. Unlike earlier programming, the provider’s broadcast is completely digital, which means it has high picture and stereo sound quality. Early satellite television was broadcast in C-band - radio in the 3.4- gigahertz (GHz) to 7-GHz frequency range. Digital broadcast satellite transmits programming in the Ku frequency range (10 GHz to 14 GHz). There are five major components involved in a direct to home (DTH) satellite.

1. JODHPUR INSTITUTE OF ENGINEERING AND TECHNOLOGY
A PRESENTATION ON SEMINAR TOPIC
DTH TECHNOLOGY
Guide
PROF. PRADEEP KUMAR SHARMA
Submitted by:-
SURAJ SINGH SOLANKI
B.Tech 4th year (8th semester)
Branch : Electronics and Communication
Engineering
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2. 2
CONTENTS
 Definition of DTH.
 Components for DTH.
 Working Procedure of DTH.
 Working of DTH components.
 Broadcasting Centre.
 Satellite.
 Dish antenna.
 Set top Box.

3. 3
DEFINITION OF DTH
o DTH stands for Direct-to-Home.
o Direct to home (DTH) television is a wireless system for delivering
television programs directly to the viewer's house.
o In DTH television, the broadcast signals are transmitted from
satellites orbiting the Earth to the viewer's house.
o Each satellite is located approximately 36,000 km above the Earth
in geosynchronous orbit.
o These satellites receive the signals from the broadcast stations
located on Earth and rebroadcast them to the Earth.

4. 4
COMPONENTS FOR DTH
There are 5 main components of DTH:
o Programming Sources.
o Broadcasting centre.
o Satellites.
o Dish antennas.
o Receiver (set top box).

5. 5
WORKING PROCEDURE OF DTH
Fig.1 : Working Procedure of DTH

6. 6
WORKING OF DTH COMPONENTS
o Programming Sources: These are simply the channel that provides
programming/content for broadcasting like movies, live matches and shows etc. They
Broadcast their via satellite.
o Broadcasting Centre: It is the central hub of the system which receives the all
programming channels from satellite and transmit it in wave form towards the satellite.
Uplink frequency range – 17.3 to 17.8 GHz
Downlink frequency range – 12.2 to 12.7 GHz
o Satellites: Which the signals from broadcast station and re-broadcast to them on the
earth.
o Dish: It picks up the signal from the satellite and passes it on to the receivers in the
viewers house.
o Receiver: It processes the signal and passes it to the standard television. Ex. Set top
Box, which demodulates the received signal and converts into audio and video signal.

7. 7
BROADCASTING CENTRE
o The broadcasting centre
is the central hub of the
whole DTH system.
o It doesn’t create the
programs/content directly
of the channel, it pays an
amount to the channel
company receives the
signal from them through
satellite.
Fig.2 : Broadcasting Centre

8. 8
BROADCASTING CENTRE
o The encoder converts the audio, video & data signals into the digital format &
the multiplexer mixes these signals.
o Now the multiplexed output signal is then modulated by QPSK modulator.
o Then the modulated signal is amplified by IF amplifier.
o Encryption scrambles the digital data in such a way that it can decrypted by
those receiver, which has the correct decoding satellite receiver with
decryption algorithm and security keys.
o It transmit it into space towards satellite , which frequency is in the range of
17.3 to 17.8 GHz.
Fig.3 : Block diagram of broadcasting centre

9. 9
SATELLITE
 Geostationary satellites are positioned
at an exact height above the earth
(about 36000 Km).
 At this height they rotate around the
earth at the same speed as the earth
rotates around its axis, so in effect
remaining stationary above a point on
the earth (normally directly overhead
the equator).
 It basically receives the signal from
broadcasting center and rebroadcast
them towards earth in the wide area.
Fig.4 : Rebroadcasting of signal
through Satellite towards the earth

10. 10
DISH ANTENNA
 The standard dish consists of a
parabolic (bowl-shaped)
surface and a central feed horn
(LNB).
 It receives the signal from
satellite & through parabolic
surface, it is focused towards
the feeder i.e. LNB (Low noise
block down converter)
frequency .
Fig.5: Parabolic dish
Antenna

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 When a beam hits the
curved dish, the parabola
shape reflects the radio
signal inward onto a
particular point, just like a
concave mirror focuses
light onto a particular point.
 The curved dish focuses
incoming radio waves onto
the feed horn.
DISH ANTENNA
Fig.6: Reflection of signal through parabolic reflector and
focusing towards LNB

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 The central element in the feed horn is
low noise block-down converter.
 An LNB sits on the end of an arm and
faces the parabolic reflector(dish) which
focuses the signals from a satellite into
the feed horn of the LNB.
 Block-down converter (so called because
it converts a whole band or ‘block of
frequencies’ to a lower band) i.e. it
converts the 12.2 to 12.7 GHz band to
950 to 1450 MHz and then it sends to the
Set top box through Coaxial cable.
DISH ANTENNA
Fig.7: LNB (Low noise block down
Converter)

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SET TOP BOX
Fig.8: Block diagram of set top box

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o The set top box accepts the entire down converted band & separates out
the individual transponder frequency.
o Then signals are first converted to fixed IF & then QPSK demodulated.
o Then the decoder extracts the bits for wanted channel, & sends them to
MPEG decoder, & finally generates analog Audio & Video signals with
DIA converters to drive TV set.
o The microcontroller controls the functioning of all the blocks of DTH.
SET TOP BOX

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 It is cost effective communication,
information and entertainment to all .
 With DTH service we can get direct
television services to our home.
 DTH also give us best sound and
clear picture quality.
 With DTH service we can select the
channel programs as our choice.
ADVANTAGES OF DTH

16. DISADVANTAGES OF DTH
 Service is interrupted if the Direction of Dish is changed.
 Transmission is interrupted due to sun outage.
 We cannot shift to other service provider as it was linked. We must
buy a new set top box.
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17. 17
 Study Of Recent Developments In DTH (Direct-To-Home) Technology by
Dheeraj Gandla. Dheeraj Gandla Int. Journal of Engineering Research and
Applications Vol. 3, Issue 5, Sep-Oct 2013, pp.628-635
 Aychaudhuri, Dipankar, et al. "An HDTV compression system." U.S. Patent No.
5,122,875. 16 Jun. 1992.
BOOKS:
 Electronic Communication Systems – Wayne Tomasi.
 Communication Systems – M.V. Raghunadh.
REFERENCES

18. THANKYOU
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