Seminar on direct to home
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Transcript of Seminar on direct to home
WELCOME
ARYAN INSTITUTE OF TECHNOLOGY GHAZIABAD
SEMINAR
DTH
DTH can be defined as :
The reception of satellite programmers with a personal dish
at individual home.
DTH does not require the local cable operator and put the
broadcaster directly in touch with the consumer.
WHAT IS DTH
DTH Stand’s for Direct to home television .
HISTORYThe first person who invented the technology for DTH was sir ARTHURE CLARLES CLARKE , a british inventor in late 1946.The DTH service was first proposed in INDIA in 1996 , but was not approved due to concern over national security.Finally , 2000 DTH service was allowded and Doordarshan was first to
To provide the service to the consumers from 1st of April ,2000.
After this other DTH service provider like ZEE and STAR starded
pushing hard for DTH service in INDIA and setup earth station whose cost was 2.15 million and was valid
for 10 years in INDIA.
MAIN PARAMETER OF DTH DTH network consist of
Broadcasting center .Satellite encodes.
Multiplexer.Modulator.
DTH receiver.
DTH NETWORK
UPLINK ANTENNAUplink satellite dishes are large in size which provides accurate
aiming and increase signal strength
The y are pointed toward specific satellite and the frequency used
is specific so that satellite transponder can receive the signal.
The EIRP (Effective isotropically radiated power) for the uplink
antenna
EIRP = Pt – Lc + Ga
Where Pt = Power of transmitter (dbm)
Lc = Line loss(db)Ga = Gain of antenna(dbi)
SATELLITEA typical satellite can have 32
transponder for Ku band (10 Ghz to 18 Ghz) and 24 transponder for
C band( 4 Ghz to 8 Ghz).A typical transponder can
have bandwidth between 27 Mhz to 50 Mhz.
The satellite retransmits the signal back to earth in Ku band
and C band frequency.
MINIDISH ANTENNA It is parabolic reflector it receives the signal and fed to the LNBF(low noise band down converter) ,which works as a receiver for signal transmitted by satellite. LNBF
Parabolic reflector
( 60 to 120 cm )
SIGNAL RECEIVED BY MINIDISH
LOW NOISE BLOCK DOWN CONVERTER(LNBF)
It collect the signal from minidish.
It receive the signal from Ku band and down convert to radio frequency
signal.It amplify and remove the distortion
from the received signal.
BLOCK DIAGRAM OF DTH SYSTEM
Low noise amplifier
Down Converter
Amplifier
Down Converter
Tunable Local Oscillator
Filter
Demodulator
TV SET
Video baseband
Channel selector
Low noise block down converter
COAXIAL CABLE The coaxial cable connect LNBF to
set top box.A transmission cable consist of
outer metal condutor
enclosing and insulated from a
central conduting core.
Impedance provided by the coaxial cable
can be calculated by the formulaZ0 =( 1/2∏)√μ/ ε ln(D/d)
Where μ = relative permeability of
inisulator ε = dielectric constant
D =outer diameter of the coaxial cable
d = inner diameter of coaxial cable.
A settop box can demodulate
the received signal and can convert these
signal into audio and
video signal.
SETTOP BOX
SET TOP BOX
TUNER DEMODULATOR
DECODER
AMPLIFIER
MICROCONTROLLER
DISH ANTENNA
CAS SYSTEM
A
V
GENERAL BLOCK DIAGRAM OF SETTOP BOX
TUNNERIt select particular channel range
from 48 Mhz to 840 MhzDEMODULATOR
Selected channel demodulated and fed to decoder
DECODERIt is a D to A converter which
provide audio and video signal as output.
MICROCONTROLLERIt control all the process performed
by each block.
HOW DOES DTH DIFFER FROM CABLE TVIn DTH , TV channel are directly
transmitted from satellite to a small dish antenna at the
subscriber home.The broadcaster directly
connect to the subscriber ,the middlemen like local cable
operator are not there in the picture , hence provide better picture quality directly from
satellite to the user.
The cable TV was limited to the urban area ,but the DTH followed
cable TV in urban as well as in rural area.
DTH technology is more resistive to the weather condition ,it can work in
any type of environment.Since coaxial cable connection are
used in DTH technology less distortion of the signal take place ,
which ultimately provides better picture quality and better signal.
FUTUTRE PROSPECT OF DTHThe DTH market in
INDIA is relatively incresing day by day
and in next 5 years (by 2014 ) we will be able
to add another 30 million subscriber.
In the next 5 years ..,we have manage to overtake JAPAN as
the largest DTH market in ASIA.
DTH SERVICE PROVIDER
CONCLUSIONDTH has made the hopes for
people of the rural area to come true.
It help to develop the economy condition of our country
It provide the wide thinking of rural people which helps to
develop the culture of society.