DTH Technology or (Direct To Home) Technology has acquired a key position in TV broadcasting industry in the last decade. This article will discuss DTH (Direct To Home) Technology, its architecture, components, how it works and its advantages over conventional cable TV services.
What is DTH Technology
DTH stands for Direct-To-Home. Direct-To-Home service is a digital satellite service that provides television services direct to home with a personal dish. Local cable operators are not required in DTH and puts the broadcaster directly in touch with the consumer.
Direct to Home Technology provides better picture and sound quality. It also offers services like internet access, video conferencing and email. HDTV (High Definition TV) and 3D TV are the enhanced features of this Technology. It also has options to record/rewind/pause live TV.
Fig. 1 – Introduction to DTH (Direct To Home) Technology
Components of DTH Technology
DTH (Direct to Home) System consists of the following components:
- Dish Antenna
- LNBF (Low Noise Block Down Converter plus Feedhorn)
- Coaxial Cable
- Set Top Box
It is a Parabolic Reflector. It receives the signal and redirects it to the LNBF which works as receiver for signal transmitted by satellite Parabolic Reflector.
LNBF (Low Noise Block Down Converter Feedhorn)
Small metal horn antenna on the Dish is called as Feedhorn. It collects the signal from dish and amplifies the signal bouncing off the dish and filters out the noise (signals not carrying programming).
It is the Cable that connects mini Dish and Set Top Box.
DTH Set Top Box
DTH Set Top Box, unlike the regular cable connection, decodes the encrypted transmission data and converts these signals into audio & video signal.
Fig. 2 – Components of DTH System
Architecture of Direct To Home Technology
The architecture of Direct to Home System includes:
- Broadcasting Centre
- DTH Receiver
A Geo-Stationary Satellite plays an important role in Direct To Home system. Satellites have a much larger “line of sight” range as they are higher in the sky than TV antennas. It transmits the signals to the DTH Antenna.
The Broadcast Centre is the central hub of the system. The television provider receives signals here from various programming sources and then beams a broadcast signal to satellites which are in Geostationary orbit. The satellites receive the signals from the broadcasting station and rebroadcast them to the ground.
Multiplexer is a device which transmits the information of many channels in one channel. It is a part of the broadcasting centre. In the Broadcasting Centre, the Multiplexer compresses all the frequency signals into one single channel & transmits it to the Geo-Stationary satellite. It sends the single channel to the Modulator.
Modulation is a process in which the information signal is imposed on a carrier signal which is of high strength. The Modulator modulates the signals and sends to the Encoder.
The Encoder encodes the signals to transmit the signals. The satellite sends the signals to the DTH Antenna which further transmits them to the Set Top Box.
Receiver is the end component in the entire DTH System. It decodes or descrambles the encrypted signal. For unlocking signal, it needs the proper decoder chip for that programming package. The service provider can communicate with that chip with the help of satellite signal to make required operations to its decoding program.
Fig. 3 – Basic Architecture of DTH Technology System
How does Direct To Home (DTH) Technology Work
The Satellites which are located approximately 35700 km above the Earth’s surface transmits signals to the Broadcast stations on the Earth’s Surface. The Broadcast Centre receives the signals and Transponder on the satellite helps in establishing Communication channel between Transmitting and Receiving Units. Satellite rebroadcasts the signals which are encoded.
The Encoder converts the data, audio and video signals into the digital format and these signals are muxed or combined by the multiplexer. There will be a small Dish Antenna and Set Top Box at the user end to Receive, Decode and view numerous channels.
Fig. 4 – Schematic Representation of Working Principle
Advantages of DTH Technology
The advantages of DTH Technology include:
- Greater service coverage.
- More channels.
- Better signal quality.
- Multiple language options.
- Pay only for the channels and services that the user wants.
- Applications such as Parental Lock, Pre-booked Pay-Per-View and Impulse Pay-Per-View.
Disadvantages of DTH Technology
The disadvantages of DTH Technology include:
- One of the major problems for the subscribers of Direct To Home service is unable to view any channel during heavy rains due to weak signals.
- Changing service provider is not easy as the user has to pay additional cost to buy new Set Top Box from new service provider.
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