This document is a report submitted by Rakshit Choubey to fulfill the requirements for a Bachelor of Engineering degree in Electronics and Instrumentation. It summarizes his industrial training at Doordarshan Kendra in Indore. Doordarshan Kendra is equipped with a studio and two 10kW transmitters for DD National and DD News. The report describes the working of different types of microphones used such as dynamic, ribbon, and condenser microphones. It provides technical details of the transmitters including frequency, power output, and coverage area.
ppt Or report of training on doordarshan TV broadcasting Siraj Ahmed
The document provides an overview of broadcasting at Doordarshan Kendra in Silchar, India. It discusses the key components of a Doordarshan studio including the studio itself, lighting, acoustic systems, cameras, and transmitter. It also describes the earth station that is used to send program signals to satellites for transmission and reception, and outlines the basic process of transmission from uplinking to satellites to downlinking to receivers.
Doordarshan, the national television service of India, is devoted to public service broadcasting. It is one of the largest terrestrial networks in the world. In the Industrial training at Doordarshan Kendra, Lucknow, provided useful knowledge which will surely be of great help in future.
This report gives an opportunity to learn the practical aspects of the knowledge of Electronics and communication. Doordarshan Kendra is a milestone in the field of entertainment and education media source. Doordarshan, Lucknow is the Program Production Center and transmission. The studios are housed at same campus and the transmitter is located at the Lucknow.
This document is Amal Roshan's summer training report submitted to NIT Calicut. It includes declarations and certificates signed by Amal Roshan and his guide, as well as sections on:
- The history of Doordarshan and Doordarshan Patna, where Amal did his summer training.
- Fundamentals of monochrome and colour TV systems, including picture formation, scanning, and interlacing.
- Details of the studio setup and coverage at Doordarshan Patna, including cameras, transmitters, and facilities.
Mobile satellite communication uses satellites to enable communication between mobile users. There are different types of satellite orbits used - geostationary, medium earth orbit, and low earth orbit. Each orbit has advantages and disadvantages for mobile communication. Mobile satellite services include maritime, land, aeronautical, personal, and broadcast. Signal propagation is impaired by effects like reflection, refraction, shadowing, and different types of noise. Thermal noise places a fundamental limit on communication performance.
This document provides an outline for a course on digital satellite communications. It begins with course objectives, then provides an introduction to satellite communication principles. The basics section explains how satellite communication works, including earth station components and signal transmission. It also covers satellite types like GEO, LEO and MEO, as well as factors that impair signals. The document discusses frequency bands, network configurations, capacity allocation methods, and applications of satellite technology. Overall it aims to give students an overview of digital satellite communication systems and components.
The word "satellite" refers to a machine that is launched into space and moves around Earth or another body in space.
The moon is the of natural satellites of earth. Thousands of artificial, or man-made, satellites moves around the Earth.
This document discusses the history and basics of satellite communication systems. It covers:
- The first satellites launched in the 1940s-1990s and the development of satellite phone systems.
- The types of satellite orbits including LEO, MEO, and GEO and how factors like altitude and inclination determine satellite period and coverage areas.
- How satellite systems extend cellular networks to provide global mobile communication through techniques like inter-satellite links and handovers between satellites and gateways.
- The challenges of satellite systems including higher latency compared to terrestrial networks and the need for complex routing and localization as satellites move.
Doordarshan is the public television broadcaster of India and a division of Prasar Bharti, and nominated by the Government of India. It is one of the largest broadcasting organizations in the world in terms of the infrastructure of studios and transmitters.
Doordarshan Kendra is amilestone in the field of entertainment and education media source. Doordarshan, muzaffarpur is the Program Production Center and transmition .. The studios are housed at same campus and the transmitter is located at the muzaffarpur.
AIR and Doordarshan aims to provide information, education and entertainment for the public. Its network of 1400 terrestrial transmitters cover more than 90.7% of India's
ppt Or report of training on doordarshan TV broadcasting Siraj Ahmed
The document provides an overview of broadcasting at Doordarshan Kendra in Silchar, India. It discusses the key components of a Doordarshan studio including the studio itself, lighting, acoustic systems, cameras, and transmitter. It also describes the earth station that is used to send program signals to satellites for transmission and reception, and outlines the basic process of transmission from uplinking to satellites to downlinking to receivers.
Doordarshan, the national television service of India, is devoted to public service broadcasting. It is one of the largest terrestrial networks in the world. In the Industrial training at Doordarshan Kendra, Lucknow, provided useful knowledge which will surely be of great help in future.
This report gives an opportunity to learn the practical aspects of the knowledge of Electronics and communication. Doordarshan Kendra is a milestone in the field of entertainment and education media source. Doordarshan, Lucknow is the Program Production Center and transmission. The studios are housed at same campus and the transmitter is located at the Lucknow.
This document is Amal Roshan's summer training report submitted to NIT Calicut. It includes declarations and certificates signed by Amal Roshan and his guide, as well as sections on:
- The history of Doordarshan and Doordarshan Patna, where Amal did his summer training.
- Fundamentals of monochrome and colour TV systems, including picture formation, scanning, and interlacing.
- Details of the studio setup and coverage at Doordarshan Patna, including cameras, transmitters, and facilities.
Mobile satellite communication uses satellites to enable communication between mobile users. There are different types of satellite orbits used - geostationary, medium earth orbit, and low earth orbit. Each orbit has advantages and disadvantages for mobile communication. Mobile satellite services include maritime, land, aeronautical, personal, and broadcast. Signal propagation is impaired by effects like reflection, refraction, shadowing, and different types of noise. Thermal noise places a fundamental limit on communication performance.
This document provides an outline for a course on digital satellite communications. It begins with course objectives, then provides an introduction to satellite communication principles. The basics section explains how satellite communication works, including earth station components and signal transmission. It also covers satellite types like GEO, LEO and MEO, as well as factors that impair signals. The document discusses frequency bands, network configurations, capacity allocation methods, and applications of satellite technology. Overall it aims to give students an overview of digital satellite communication systems and components.
The word "satellite" refers to a machine that is launched into space and moves around Earth or another body in space.
The moon is the of natural satellites of earth. Thousands of artificial, or man-made, satellites moves around the Earth.
This document discusses the history and basics of satellite communication systems. It covers:
- The first satellites launched in the 1940s-1990s and the development of satellite phone systems.
- The types of satellite orbits including LEO, MEO, and GEO and how factors like altitude and inclination determine satellite period and coverage areas.
- How satellite systems extend cellular networks to provide global mobile communication through techniques like inter-satellite links and handovers between satellites and gateways.
- The challenges of satellite systems including higher latency compared to terrestrial networks and the need for complex routing and localization as satellites move.
Doordarshan is the public television broadcaster of India and a division of Prasar Bharti, and nominated by the Government of India. It is one of the largest broadcasting organizations in the world in terms of the infrastructure of studios and transmitters.
Doordarshan Kendra is amilestone in the field of entertainment and education media source. Doordarshan, muzaffarpur is the Program Production Center and transmition .. The studios are housed at same campus and the transmitter is located at the muzaffarpur.
AIR and Doordarshan aims to provide information, education and entertainment for the public. Its network of 1400 terrestrial transmitters cover more than 90.7% of India's
If the communication takes place between any two earth stations through a satellite, then it is called as satellite communication. In this communication, electromagnetic waves are used as carrier signals.
Introduction
Need for communication
Satellite Communication
How a satellite works
Frequency Band of a satellite communication
Kepler’s Laws
Earth Orbit satellites
● Geosynchronous Earth Orbit
● Medium Earth Orbit
● Low Earth Orbit
Subsystems
● Space Subsystem
AOC Subsystem
TTCM Subsystem
Power and Antenna Subsystems
Transponders
● Earth Subsystem
Transmitter
Receiver
Earth Station Antenna
Tracking Subsystem
Multiple Access Techniques
● FDMA (Frequency Division Multiple Access)
● TDMA (Time Division Multiple Access)
● CDMA (Code Division Multiple Access)
Satellite Communication Services
● One-way satellite communication link service
● Two-way satellite communication link service
Global Positioning System
● GPS codes and services
● GPS receiver
Advantages
Disadvantages
Application
Bibliography
Conclusion
The document discusses satellite communication systems. It provides background on the history of satellite communications beginning in 1945. It then describes different types of satellite systems including geostationary, low earth orbit (LEO), and medium earth orbit (MEO) systems. Finally, it discusses key concepts for satellite systems such as localization, handover procedures, and examples of operational LEO and MEO networks.
Thermal noise from components and the environment is a major source of noise in satellite communication systems. Noise comes from internal components as well as external sources like the sun, atmosphere, and space. The signal-to-noise ratio indicates the strength of the signal relative to noise, with a higher ratio desired. Forward error correction, adaptive equalization, and diversity techniques can help compensate for noise and other issues like fading that affect signal quality. Maintaining stability, power supply, and operating in the harsh environment of space present ongoing challenges for satellite systems.
This document is Satyendra Gupta's summer industrial training report on his training at Doordarshan Kendra Lucknow. It provides an overview of Doordarshan Lucknow and describes the key divisions of Studio, Transmitter, and Earth Station. It also covers the fundamentals of monochrome and color television systems as well as concepts like the color composite video signal, television cameras, lighting, microphones, video tape recording, vision mixing, 3D graphics, transmission, antennas, outdoor broadcasting vans, and direct-to-home satellite broadcasting.
Communication satellites orbit Earth and are used to transmit radio, television and other signals. The first artificial satellite was Sputnik 1, launched in 1957. There are different types of satellites including active satellites that amplify and retransmit signals, addressing disadvantages of early passive satellites. Geostationary satellites orbit at the same rate as Earth's rotation, allowing ground antennas to remain fixed. Other orbits include medium Earth orbit and low Earth orbit. VSAT systems use small ground terminals to communicate via satellite. GPS uses a constellation of satellites to provide location services worldwide.
1) A satellite communication system consists of a communication satellite in orbit that receives and amplifies signals and redirects them, a ground-based control station, and earth stations for transmission and reception.
2) Satellites receive signals from earth stations, amplify and translate frequencies, and broadcast to other earth stations. Signals travel from an earth station to the satellite and back to another earth station.
3) Satellite transponders act as repeaters with receivers and transmitters, picking up signals from earth, amplifying them, translating frequencies, and retransmitting to earth.
ATI Courses Satellite Communications Systems Engineering Professional Develop...Jim Jenkins
ATI Courses Satellite Communications Systems Engineering course sampler. This three-day course is designed for satellite communications engineers, spacecraft engineers, and managers who want to obtain an understanding of the "big picture" of satellite communications. Each topic is illustrated by detailed worked numerical examples, using published data for actual satellite communications systems. The course is technically oriented and includes mathematical derivations of the fundamental equations. It will enable the participants to perform their own satellite link budget calculations. The course will especially appeal to those whose objective is to develop quantitative computational skills in addition to obtaining a qualitative familiarity with the basic concepts.
The document discusses various terms and concepts related to satellite communications. It describes different types of satellites based on coverage area, service provided, and orbit. It also defines terms like earth stations, uplinks, downlinks, transponders, elevation angles, and coverage angles. Finally, it discusses concepts like frequency division multiple access (FDMA), time division multiple access (TDMA), different satellite orbits like GEO, LEO and MEO, and factors that affect satellite link performance.
Satellite communication provides long distance communication by using satellites to transmit signals between locations on Earth. There are three types of satellites - active satellites that amplify and change the frequency of signals, passive satellites that simply reflect signals, and broadcasting satellites used for radio and television. Satellites orbit Earth in different patterns depending on their inclination and eccentricity. Key elements of satellite communication systems are the space segment including satellites, and the ground segment including earth stations. Satellite communication services can be one-way, such as broadcasting, or two-way, such as telephone calls.
This document provides an overview of satellite communication. It discusses what satellites are, how satellite communication works using satellites as relay stations, the different types of satellites and orbits. It describes the key elements of a satellite communication system including the space and ground segments. It outlines various satellite communication services such as one-way and two-way links. Finally, it discusses the advantages and disadvantages of satellite communication as well as its applications.
This document provides an overview of 5 units that make up a course on satellite communication systems:
1) Orbital mechanics, orbits, and launching methods. 2) Geostationary orbit and the space segment. 3) The earth segment and space link. 4) Satellite access methods including FDMA, TDMA, and CDMA. 5) Geographic information systems and their integration with remote sensing from satellites. It also lists 4 textbooks and 4 references for further reading on topics within satellite communications.
Satellite communication uses satellites in geosynchronous orbit to provide wide area coverage of the Earth's surface for transmission of data. There are over 750 communication satellites currently in use. Satellites can transmit signals over long distances with only a 0.3 second delay and transmission costs do not depend on distance between locations. Common satellite systems use different frequency bands for uplinks and downlinks to mitigate interference. Common satellite orbits include low earth orbit (LEO), medium earth orbit (MEO), and geosynchronous earth orbit (GEO). VSAT networks use small satellite dishes for a star topology that is well-suited for centralized networks like banking.
Satellite systems provide global coverage without the need for wiring infrastructure. They can broadcast TV and radio signals and provide telecommunication services. Early systems included Syncom (1963), the first geostationary satellite, and Intelsat (1965), the first commercial geostationary system. Modern systems include Iridium (66 satellites at 780km), Globalstar (48 satellites at 1414km), and proposed systems like Teledesic (288 satellites at 700km) that provide voice and data services from low Earth orbit. Handover between satellites and ground stations allows mobility but introduces complexity in routing calls and data.
The document discusses satellite communication and the key components involved. It covers:
1) The three main segments of a satellite link - the transmitting Earth station, the satellite, and the receiving Earth station.
2) Components of Earth stations including antennas, amplifiers, modulators, and more.
3) Factors that impact satellite transmission such as frequency bands, transmission losses, polarization, and more.
The document discusses satellite link design and communication. It covers:
- The history of satellite communication from 1945 to 1998.
- Different types of satellite orbits including LEO, MEO, GEO and their applications.
- Elements of a satellite link such as transmit power, antenna gain, path losses, receiver properties and design margins.
- Concepts like free space path loss, additional losses, Shannon capacity formula, EIRP and frequencies/wavelengths.
- Factors affecting satellite signal propagation like elevation angle and atmospheric effects.
- Standards like DVB-S used for digital satellite television and radio.
The document provides an overview of satellite communication systems. It discusses key topics such as:
1. How satellite communication works by transmitting signals between Earth-based stations and satellites.
2. The components involved including the uplink from Earth to satellite and downlink from satellite to Earth.
3. Technical aspects like frequency bands, conversions, and satellite positioning in geostationary orbit.
4. Applications of satellite communication including broadcasting, internet access, and GPS navigation.
This document provides an overview of satellite communication and satellite systems. It discusses different types of transmission systems including radio, coaxial cable, and optical fiber systems. It describes how radio systems use electromagnetic waves to transmit signals and the portions of the frequency spectrum used. The document outlines the layers of the atmosphere and how the ionosphere and troposphere can propagate radio waves. It also categorizes different types of radio communication including ionosphere communication, line of sight microwave communication, and troposphere scatter communication. The document discusses advantages of satellite communication and components of a satellite communication network including the space and ground segments. It covers topics like satellite orbits, frequency bands used, and multiple access techniques in satellite systems.
The document discusses satellite communications, beginning with the basics of how satellites work as relay stations between two earth stations. It describes the advantages and disadvantages of satellite communication compared to terrestrial systems. The types of satellite orbits - GEO, LEO, MEO, and Molniya - are outlined, along with factors that affect satellite transmission. The document concludes by covering capacity allocation methods like FDMA and TDMA, and the frequency bands used in satellite communications.
This document discusses various topics related to microwave and satellite communication systems including:
1. Microwave systems are classified as long haul or short haul based on the distance served and frequency bands used. Common frequency bands include 2GHz, 4GHz, 6GHz, 7GHz, and 11GHz.
2. Satellites can provide communication services from various orbits including Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and Geosynchronous Earth Orbit (GEO). A transponder on each satellite receives and retransmits signals to allow communication between Earth stations.
3. Factors like orbit altitude, orbital speed, and rotation period distinguish different categories of satellites like LEO, MEO,
Satellite communications uses satellites as relay stations to transmit signals between Earth stations that are too far for direct transmission. Signals are sent to the satellite (uplink) and retransmitted to another station (downlink). Satellites provide wide coverage and transmission costs are independent of distance. Orbits include GEO, LEO, MEO and HAPs. Capacity is allocated using FDMA or TDMA, dividing available frequencies or time slots between users.
DTH (Direct-to-Home) technology allows television broadcasts to be received directly by homes via satellite signals and a dish antenna, without requiring cable television. It began in the 1960s with early satellite transmissions but matured later. In India, DTH was proposed in 1996 but faced issues before being allowed in 2000. Major components of DTH systems include satellites that transmit signals, a broadcast center that receives programming and beams it to satellites, multiplexers that combine channels, and set-top boxes that receive the signals for viewing.
I'm Parikshit Kuldiya. i have done my traing at AIR Jodhpur. This Report is all about ALL INDIA RADIO JODHPUR, Prasar Bharati. as there are now resources to get this Report on net..i had to suffer a lot..so this is dedicated to all my friends who have done their training from AIR JODHPUR.
If the communication takes place between any two earth stations through a satellite, then it is called as satellite communication. In this communication, electromagnetic waves are used as carrier signals.
Introduction
Need for communication
Satellite Communication
How a satellite works
Frequency Band of a satellite communication
Kepler’s Laws
Earth Orbit satellites
● Geosynchronous Earth Orbit
● Medium Earth Orbit
● Low Earth Orbit
Subsystems
● Space Subsystem
AOC Subsystem
TTCM Subsystem
Power and Antenna Subsystems
Transponders
● Earth Subsystem
Transmitter
Receiver
Earth Station Antenna
Tracking Subsystem
Multiple Access Techniques
● FDMA (Frequency Division Multiple Access)
● TDMA (Time Division Multiple Access)
● CDMA (Code Division Multiple Access)
Satellite Communication Services
● One-way satellite communication link service
● Two-way satellite communication link service
Global Positioning System
● GPS codes and services
● GPS receiver
Advantages
Disadvantages
Application
Bibliography
Conclusion
The document discusses satellite communication systems. It provides background on the history of satellite communications beginning in 1945. It then describes different types of satellite systems including geostationary, low earth orbit (LEO), and medium earth orbit (MEO) systems. Finally, it discusses key concepts for satellite systems such as localization, handover procedures, and examples of operational LEO and MEO networks.
Thermal noise from components and the environment is a major source of noise in satellite communication systems. Noise comes from internal components as well as external sources like the sun, atmosphere, and space. The signal-to-noise ratio indicates the strength of the signal relative to noise, with a higher ratio desired. Forward error correction, adaptive equalization, and diversity techniques can help compensate for noise and other issues like fading that affect signal quality. Maintaining stability, power supply, and operating in the harsh environment of space present ongoing challenges for satellite systems.
This document is Satyendra Gupta's summer industrial training report on his training at Doordarshan Kendra Lucknow. It provides an overview of Doordarshan Lucknow and describes the key divisions of Studio, Transmitter, and Earth Station. It also covers the fundamentals of monochrome and color television systems as well as concepts like the color composite video signal, television cameras, lighting, microphones, video tape recording, vision mixing, 3D graphics, transmission, antennas, outdoor broadcasting vans, and direct-to-home satellite broadcasting.
Communication satellites orbit Earth and are used to transmit radio, television and other signals. The first artificial satellite was Sputnik 1, launched in 1957. There are different types of satellites including active satellites that amplify and retransmit signals, addressing disadvantages of early passive satellites. Geostationary satellites orbit at the same rate as Earth's rotation, allowing ground antennas to remain fixed. Other orbits include medium Earth orbit and low Earth orbit. VSAT systems use small ground terminals to communicate via satellite. GPS uses a constellation of satellites to provide location services worldwide.
1) A satellite communication system consists of a communication satellite in orbit that receives and amplifies signals and redirects them, a ground-based control station, and earth stations for transmission and reception.
2) Satellites receive signals from earth stations, amplify and translate frequencies, and broadcast to other earth stations. Signals travel from an earth station to the satellite and back to another earth station.
3) Satellite transponders act as repeaters with receivers and transmitters, picking up signals from earth, amplifying them, translating frequencies, and retransmitting to earth.
ATI Courses Satellite Communications Systems Engineering Professional Develop...Jim Jenkins
ATI Courses Satellite Communications Systems Engineering course sampler. This three-day course is designed for satellite communications engineers, spacecraft engineers, and managers who want to obtain an understanding of the "big picture" of satellite communications. Each topic is illustrated by detailed worked numerical examples, using published data for actual satellite communications systems. The course is technically oriented and includes mathematical derivations of the fundamental equations. It will enable the participants to perform their own satellite link budget calculations. The course will especially appeal to those whose objective is to develop quantitative computational skills in addition to obtaining a qualitative familiarity with the basic concepts.
The document discusses various terms and concepts related to satellite communications. It describes different types of satellites based on coverage area, service provided, and orbit. It also defines terms like earth stations, uplinks, downlinks, transponders, elevation angles, and coverage angles. Finally, it discusses concepts like frequency division multiple access (FDMA), time division multiple access (TDMA), different satellite orbits like GEO, LEO and MEO, and factors that affect satellite link performance.
Satellite communication provides long distance communication by using satellites to transmit signals between locations on Earth. There are three types of satellites - active satellites that amplify and change the frequency of signals, passive satellites that simply reflect signals, and broadcasting satellites used for radio and television. Satellites orbit Earth in different patterns depending on their inclination and eccentricity. Key elements of satellite communication systems are the space segment including satellites, and the ground segment including earth stations. Satellite communication services can be one-way, such as broadcasting, or two-way, such as telephone calls.
This document provides an overview of satellite communication. It discusses what satellites are, how satellite communication works using satellites as relay stations, the different types of satellites and orbits. It describes the key elements of a satellite communication system including the space and ground segments. It outlines various satellite communication services such as one-way and two-way links. Finally, it discusses the advantages and disadvantages of satellite communication as well as its applications.
This document provides an overview of 5 units that make up a course on satellite communication systems:
1) Orbital mechanics, orbits, and launching methods. 2) Geostationary orbit and the space segment. 3) The earth segment and space link. 4) Satellite access methods including FDMA, TDMA, and CDMA. 5) Geographic information systems and their integration with remote sensing from satellites. It also lists 4 textbooks and 4 references for further reading on topics within satellite communications.
Satellite communication uses satellites in geosynchronous orbit to provide wide area coverage of the Earth's surface for transmission of data. There are over 750 communication satellites currently in use. Satellites can transmit signals over long distances with only a 0.3 second delay and transmission costs do not depend on distance between locations. Common satellite systems use different frequency bands for uplinks and downlinks to mitigate interference. Common satellite orbits include low earth orbit (LEO), medium earth orbit (MEO), and geosynchronous earth orbit (GEO). VSAT networks use small satellite dishes for a star topology that is well-suited for centralized networks like banking.
Satellite systems provide global coverage without the need for wiring infrastructure. They can broadcast TV and radio signals and provide telecommunication services. Early systems included Syncom (1963), the first geostationary satellite, and Intelsat (1965), the first commercial geostationary system. Modern systems include Iridium (66 satellites at 780km), Globalstar (48 satellites at 1414km), and proposed systems like Teledesic (288 satellites at 700km) that provide voice and data services from low Earth orbit. Handover between satellites and ground stations allows mobility but introduces complexity in routing calls and data.
The document discusses satellite communication and the key components involved. It covers:
1) The three main segments of a satellite link - the transmitting Earth station, the satellite, and the receiving Earth station.
2) Components of Earth stations including antennas, amplifiers, modulators, and more.
3) Factors that impact satellite transmission such as frequency bands, transmission losses, polarization, and more.
The document discusses satellite link design and communication. It covers:
- The history of satellite communication from 1945 to 1998.
- Different types of satellite orbits including LEO, MEO, GEO and their applications.
- Elements of a satellite link such as transmit power, antenna gain, path losses, receiver properties and design margins.
- Concepts like free space path loss, additional losses, Shannon capacity formula, EIRP and frequencies/wavelengths.
- Factors affecting satellite signal propagation like elevation angle and atmospheric effects.
- Standards like DVB-S used for digital satellite television and radio.
The document provides an overview of satellite communication systems. It discusses key topics such as:
1. How satellite communication works by transmitting signals between Earth-based stations and satellites.
2. The components involved including the uplink from Earth to satellite and downlink from satellite to Earth.
3. Technical aspects like frequency bands, conversions, and satellite positioning in geostationary orbit.
4. Applications of satellite communication including broadcasting, internet access, and GPS navigation.
This document provides an overview of satellite communication and satellite systems. It discusses different types of transmission systems including radio, coaxial cable, and optical fiber systems. It describes how radio systems use electromagnetic waves to transmit signals and the portions of the frequency spectrum used. The document outlines the layers of the atmosphere and how the ionosphere and troposphere can propagate radio waves. It also categorizes different types of radio communication including ionosphere communication, line of sight microwave communication, and troposphere scatter communication. The document discusses advantages of satellite communication and components of a satellite communication network including the space and ground segments. It covers topics like satellite orbits, frequency bands used, and multiple access techniques in satellite systems.
The document discusses satellite communications, beginning with the basics of how satellites work as relay stations between two earth stations. It describes the advantages and disadvantages of satellite communication compared to terrestrial systems. The types of satellite orbits - GEO, LEO, MEO, and Molniya - are outlined, along with factors that affect satellite transmission. The document concludes by covering capacity allocation methods like FDMA and TDMA, and the frequency bands used in satellite communications.
This document discusses various topics related to microwave and satellite communication systems including:
1. Microwave systems are classified as long haul or short haul based on the distance served and frequency bands used. Common frequency bands include 2GHz, 4GHz, 6GHz, 7GHz, and 11GHz.
2. Satellites can provide communication services from various orbits including Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and Geosynchronous Earth Orbit (GEO). A transponder on each satellite receives and retransmits signals to allow communication between Earth stations.
3. Factors like orbit altitude, orbital speed, and rotation period distinguish different categories of satellites like LEO, MEO,
Satellite communications uses satellites as relay stations to transmit signals between Earth stations that are too far for direct transmission. Signals are sent to the satellite (uplink) and retransmitted to another station (downlink). Satellites provide wide coverage and transmission costs are independent of distance. Orbits include GEO, LEO, MEO and HAPs. Capacity is allocated using FDMA or TDMA, dividing available frequencies or time slots between users.
DTH (Direct-to-Home) technology allows television broadcasts to be received directly by homes via satellite signals and a dish antenna, without requiring cable television. It began in the 1960s with early satellite transmissions but matured later. In India, DTH was proposed in 1996 but faced issues before being allowed in 2000. Major components of DTH systems include satellites that transmit signals, a broadcast center that receives programming and beams it to satellites, multiplexers that combine channels, and set-top boxes that receive the signals for viewing.
I'm Parikshit Kuldiya. i have done my traing at AIR Jodhpur. This Report is all about ALL INDIA RADIO JODHPUR, Prasar Bharati. as there are now resources to get this Report on net..i had to suffer a lot..so this is dedicated to all my friends who have done their training from AIR JODHPUR.
This document is Sakib Hussain's vocational training report from his 2-week training at All India Radio Kolkata. It details his training experiences at 4 centers: Akash Bani Bhaban (control room), Golf Green FM transmitter center, HPT Amtola (medium wave transmission), and HPT Amtola (medium and short wave transmission). The report is divided into 4 parts covering introductions to communication systems, AIR studio and broadcasting, AIR MW and SW transmission systems, and AIR FM transmission systems.
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.
Amateur radio is a hobby that allows individuals to communicate with other amateur radio operators around the world using radio transmitters and receivers. The document discusses how amateur radio can be used for voice communication, Morse code communication, digital communication via satellites, repeaters, and the internet. It also highlights how amateur radio operators provide important emergency communication services during disasters when other forms of communication may fail.
Fm transmitter and future radio technologyChima Chukwu
ABSTRACT
FM Transmitter is a device which generates frequency modulated signal. It is
one element of a radio system which, with the aid of an antenna, propagates
an electromagnetic signal. Standard FM broadcasts are based in the 88 - 108
MHz range. Advancements have been made in the way FM is broadcast. This
includes utilizing such technologies as Hybrid Digital (HD) Radio, Software
Defined Radio (SDR) and Cognitive Radio.
HD Radio uses IBOC (In-Band On-Channel) as a methodof broadcasting digital
radio signals on the same FM channel, and at the same time as the
conventional analog signal while Software defined radio (SDR) is the term used
to describe radio technology where some or the entire wireless physical layer
functions are software defined.
Cognitive radio networks on the other hand, are intelligent networks that can
automatically sense the environment and adapt the communication
parameters accordingly. These types of networks have applications in dynamic
spectrum access, co-existence of different wireless networks, interference
management, etc.
This document provides an overview of Doordarshan High Power Transmitter in Kanpur, including:
1. It discusses the history and components of Doordarshan, including TV studios, vision mixers, earth stations, and OB Vans.
2. While Doordarshan was an important part of electronic media in India, it is now losing viewers due to a lack of engaging content for youth and not adapting to changing market trends.
3. Suggestions are provided to help Doordarshan modernize and better utilize its resources, such as promoting content on social media and allowing more creative freedom.
This document provides information about radio broadcasting in India. It discusses:
- The history of radio broadcasting in India, beginning with the first broadcast license in 1922 and the establishment of the All India Radio network in 1936.
- The technical aspects of radio transmission, including how radio waves carry signals and how receivers convert those signals back into audio.
- The components and functions of a radio broadcasting studio, including mixing boards, recording rooms, and transmission equipment.
- Details about AIR's network today, which includes 149 MW transmitters, 54 SW transmitters, and 171 FM transmitters covering over 91% of India.
DTH (Direct to Home) technology involves transmitting satellite programming directly to small dish antennas at individual homes. It does not require a local cable operator and allows broadcasters to connect directly with consumers. DTH systems consist of an uplink antenna, satellite, minidish antenna, low noise block down converter, and set top box. DTH offers better picture quality than cable TV since the signal travels directly from satellite to user without passing through coaxial cables. DTH has expanded television access to both urban and rural areas in India.
J Kishor completed a summer internship at All India Radio in Dharwad, where he learned about radio broadcasting equipment and processes. He gained hands-on experience in radio studios and with microphones, modulation techniques, transmitters, antennas, satellite communications, and power systems. The internship provided valuable practical knowledge to supplement his electrical engineering education. Kishor thanks the staff at AIR for their support and guidance during the internship.
This document provides an overview of All India Radio (AIR) in Jodhpur, India. It discusses:
- The history and establishment of AIR, including its network of transmitters and studios.
- The three-tier broadcasting system used by AIR, including transmitters, studios, and console equipment.
- Key components like antennas, antenna arrays, and the different types of antennas used.
- Facilities like studios for drama, music, and commercial broadcasts, as well as playback and dubbing studios.
The document aims to educate about AIR's infrastructure and the technical aspects of radio broadcasting.
This document provides an overview of All India Radio (AIR) in Jodhpur, India. It discusses the history and establishment of AIR, describing how it has grown from 2.75 million receiving sets at independence to 132 million today. It also outlines AIR's three-tier broadcasting system and key components like transmitters, studios including drama, talk, music, and commercial broadcasting studios, and control consoles. The document concludes by thanking the audience and opening the floor for any questions.
The document is a seminar report on IBOC (In-Band On-Channel) technology. It discusses FM transmitters and their limitations. It then provides an overview of IBOC technology, which allows digital radio signals to be broadcast simultaneously with analog signals on the same FM channel. IBOC utilizes additional digital subcarriers or sidebands to multiplex digital information onto existing FM broadcasts without requiring new frequencies. This allows for multiple program channels but can reduce stereo bandwidth on FM. Stations can eventually transition to being fully digital. IBOC focuses on a digital transition that works within existing broadcasting infrastructure.
In my summer Vacations of Pre Final year ,I joined DDK Lucknow for my summer training.
Here i Learnt a lot which i want to share with you guys.
You can also take it as a reference slide for your presentations too.
UNDERWATER ACOUSTIC MODEM FOR SHORT –RANGE SENSOR NETWORKS ijiert bestjournal
This document describes the design of an underwater acoustic modem for short-range sensor networks. It discusses the challenges of underwater acoustic communication and outlines the major components of acoustic modems, including transducers, analog transceivers, and digital control platforms. The document then provides details on the design of an amplitude-shift keying acoustic modem, including the transmitter, receiver, and testing results. It concludes that the designed modem represents a low-cost alternative to existing commercial underwater acoustic modems.
This document summarizes the National Frequency Allocation Plan-2011 (NFAP-2011) of India. Key points:
- NFAP-2011 allocates frequency bands in India based on international and regional agreements, catering to new technologies like UWB, ITS, and short range devices.
- It aims to ensure equitable and optimal use of limited radio frequency spectrum while protecting existing services. Provisions encourage indigenous development and manufacturing.
- New technologies covered include ultra wideband devices for wireless applications, intelligent transport systems for vehicle communication, and E-band radios utilizing millimeter wave spectrum.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Design and Implementation of A VHF Tri Loop Antenna for 2 Meter Amateur Bandijtsrd
This paper presents the design and implementation of a triangular loop antenna using aluminum tubing of diameter 10mm with high electrical conductivity and reflecting ability. The antenna operates in very high frequency VHF band covering a frequency range of 140 to 150MHz. It has a gain of 3 dB and a radius of coverage of about 100 kilometers. It was constructed as a prototype antenna and tested at the author home base QTH with grid locator of PK23CO, where signals from DW4PGS, DW4PLN, DW4GSV, and DV4RBC were received with sharp audible sound Q5 and full signal strength S9 . Better receptions were recorded for PD03, KB912 19, and KB951 -B157 on days with good propagation. Measurement result shows that the proposed antenna can work properly and meet well to be used in as reliable low cost homebrew effective VHF wide band antenna and it is an omnidirectional antenna. Dexter M. Toyado "Design and Implementation of A VHF Tri-Loop Antenna for 2-Meter Amateur Band" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-6 , October 2019, URL: https://www.ijtsrd.com/papers/ijtsrd28120.pdf Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/28120/design-and-implementation-of-a-vhf-tri-loop-antenna-for-2-meter-amateur-band/dexter-m-toyado
The document summarizes a summer training presentation at Rajiv Gandhi Proudyogiki Vishwavidalaya about a 2-week internship at Doordarshan Kendra Maintenance Centre in Indore, MP. It describes the training institute and provides an overview of the TV studio components including cameras, lighting, audio equipment, and the vision mixer. It also explains the typical video and audio chains and covers other areas like the master switching room, earth station, outside broadcasting vans, and digital satellite news gathering technology. In the conclusion, it notes that Doordarshan is losing viewers due to a lack of youth programming, not utilizing assets fully, and not gathering user feedback.
DTH technology enables direct transmission of TV signals to homes through a satellite receiver installed in the house. In India, DTH services involve broadcasting encrypted multi-channel signals via satellites that subscribers can receive using a dish antenna and set-top box provided by the broadcasting company. Key components of DTH services include broadcasting centers that transmit signals to satellites, satellites that receive and rebroadcast the signals, and receivers and decoders in homes that unscramble the signals for viewing on TVs. DTH provides benefits like nationwide coverage, a large number of channel options, and eliminating intermediaries like cable operators.
1. 1
A Report on
Satellite communication and Digital earth station
INDUSTRIAL TRAINING
Doordarshan Indore
Submitted at
Rajiv Gandhi Technical University, Bhopal
In partial fulfillment of the degree
Of
Bachelor of Engineering
In
Electronics and Instrumentation
Electronics and Instrumentation Department
MEDI-CAPS INSTITUTE OF TECHNOLOGY
AND MANAGEMENT INDORE- 453331
2013-14
2. 2
A Report on
Satellite communication and Digital earth station
INDUSTRIAL TRAINING
Doordarshan Indore
Submitted at
Rajiv Gandhi Technical University, Bhopal
In partial fulfillment of the degree
Of
Bachelor of Engineering
In
Electronics and Instrumentation
Submitted by: Submitted to:
Rakshit Choubey Mr. Vinit Gupta
(0812EI101043) Industrial Training In charge
Electronics and Instrumentation Department
MEDI-CAPS INSTITUTE OF TECHNOLOGY
AND MANAGEMENT INDORE- 453331
2013-14
3. 3
Certificate
This is to certify that Mr./Miss Rakshit Choubey, student of B.E.
(Electronics and Instrumentation Engineering) , 4th Year, VII Semester ,
Medi-Caps Institute of Technology and Management has pursued his/her
Industrial Training course on TV Transmitter, Studio Equipment, Earth
Station and their associated equipments from 17/06/2013 to 12/07/2013
from Doordarshan Kendra , Indore .
Industrial Training In charge
4. 4
ACKNOWLEDGEMENT
I take this opportunity to thank Mr. Abhay Shrivastava (Assistant engineer) for his
valuable guidance and encouragement throughout the course of my training on “Satellite
communication and Digital earth station“.
Also I would like to express my gratitude to Mr. Vivek D. Kasture for offering all the
facilities, sincere co-operation, guidance, timely encouragement and thankful advice.
I am also thankful to all the Doordarshan Indore staff members who gave their time for our
training program and helped us learn some practical and theoretical aspects of our project.
5. 5
CONTENTS
Cover Page
Institution Certificate
Acknowledgement
Industry Certificate
Chapter No. Subject Page No.
1. Brief Introduction of Organization 7
2. Purpose behind visit 9
3. Machines/Equipments – Working & Specifications 10
4. Details of the Project under taken 18
5. Conclusion 24
List of Figures and Tables
References
6. 6
1. BRIEF INTRODUCTION OF ORGANISATION
Doordarshan (DD) is country’s Public Service Television and has the distinction of being
one of the world’s largest terrestrial networks. DD is the biggest media organization in the
country covering over 90.1 % of its population and 78.2 % of its area. Doordarshan operates
24 channels – Four All India Channels, Eleven Regional Languages Satellite Channels,
Eight Hindi Belt Network and One International Channel.
DD started off its operations with a Public Service Aim behind it…
• To inform
• To educate
• To entertain
Its countrymen and hence got the distinction of a PUBLIC SERVICE BROADCASTER
Doordarshan. Three-tier program service Doordarshan has a three-tier program service
National, Regional and Local. The NATIONAL Program include News, Current Affairs,
Science, Cultural Magazines, Sports, Music, Dance, Drama, Serials and Feature Films. The
REGIONAL Programs carried on all the Transmitters in the different states of India also
deal with similar programs, but in the language and idiom of the particular Region/State.
The LOCAL Programs are area specific and cover local issues featuring local people.
National and Regional Program Services of Doordarshan are also available on Satellite and
DTH.
1.1 History of Doordarshan
In 1959, Philips (India) made an offer to the Government of a transmitter at a reduced cost.
Earlier, Philips had demonstrated its use at an exhibition in New Delhi. The Government
decided employing it on an experimental basis “to train personnel, and partly to discover
what TV could achieve in community development and formal education”. A UNESCO
grant of $20,000 for the purchase of community receivers and a United States offer of some
equipment proved much too tempting to resist, and on September 15, 1959, the Delhi
Television Centre went on air for half an hour, three days a week and inaugurated by Sh.
Rajendra Prasad, President of India from Vigyan Bhawan.
7. 7
The range of the transmitter was forty kilometers round and about Delhi. Soon programs
began to be beamed twice a week, each of 20 minutes’ duration. The audience comprised
members of 180 ‘teleclubs’ which were provided sets free by UNESCO. Entertainment and
information programs were introduced from August 1965, in addition to some social
education programs for which purpose alone TV had been introduced in the capital. The
Federal Republic of Germany helped in setting up a TV production studio. By 1970, the
duration of the service was increased to three hours, and included, besides news,
information and entertainment programs, two weekly programs running to 20 minutes each
for ‘teleclubs’, and another weekly program of the same duration called ‘KrishiDarshan’ for
farmers in 80 villages.‘KrishiDarshan’ programs began in January 1967 with the help of the
Department of Atomic Energy, the Indian Agricultural Research Institute, the Delhi
Administration and the State Governments of Haryana and Uttar Pradesh. The programs
could easily be picked up in these States, as the range of the transmitter was extended to 60
kilometers. By the end of the decade there were more than 200,000 sets in Delhi and the
neighboring states. Today, Doordarshan operates 30 channels in 22 languages and is one of
the largest Terrestrial Network in the World.
8. 8
2. PURPOSE BEHIND VISIT
The main purpose of the industrial training was to understand and experience real
life situations in industrial organizations and their related environment.
To learn the formal and in-formal relationships in an industrial organization so as to
promote favorable human relations and teamwork.
To gain hands-on experience on the equipments used in the industry and to relate
them with the knowledge we gained during our engineering.
During the visit we learned various safety practices used in the industry.
9. 9
3. EQUIPMENTS - WORKING AND SPECIFICATIONS
3.1 SPECIFICATIONS:-
Doordarshan Kendra, Indore is equipped with studio, two high power transmitters for
primary channel coverage. The transmitters are of 10kW power, one is for DD National and
other is for DD News telecasting.
3.1.1 Technical Details of Transmitter
Table.1 Transmitter DD National:
Date of commissioning
Replaced by Rhode & Schwarz transmitter
28-11-1984 (Bel transmitter)
18-07-05
Make and type Rohde &Schwarz
NM7100E/V
Frequency 203.23 MHz for visual & 208.73 MHz for
aural
Output power 10kW for visual and 1 kW for aural
Primary coverage area 65-70 km radially
Table.2 Transmitter DD News:
Date of commission 03-07-2000
Make and type Thom cast 45321.165-981A
Service relayed DD-news
Band and channel VHF-III, CH#11
Frequency 217.250017 MHz for visual &
222.750015 MHz for aural.
Output power 10kW for visual and 1 kW for aural
Primary Coverage area 65-70 km radial
10. 10
3.2 WORKING:-
Microphones:
Microphones are transducers that convert acoustical energy into electrical energy. The three
main types of microphones (according to their principles of operation) are:
Dynamic(moving coil)
Ribbon
Condenser
Dynamic Microphones:
Dynamic mics consist of a diaphragm suspended in front of a magnet to which a coil of
wire is attached. The coil sits in the gaps of the magnet. Vibrations of the diaphragm make
the coil move in the gap causing an AC to flow. Coils of wire are used to increase the
magnitude of the induced voltage and current. The mass of the coil-diaphragm structure
impedes its rapid movement at high frequencies (where there is usually low response).A
resonant peak is usually found at around 5 kHz, making it a favorite with vocalists.
Fig.1 Fig.2
Ribbon microphones:
It consists of a thin strip of conductive corrugated metal(ribbon) between magnetic plates
.Vibration of the ribbon according to the acoustic wave induces a current. Its electrical
output is very small and needs to be stepped up by a transformer .The lightness of the
ribbon guarantees a flat frequency response for mid and high frequencies up to 14kHz. It
resonates at very low frequencies (around 40Hz). It is very delicate and well suited for the
recording of acoustic instruments.
11. 11
Condenser microphones:
A capacitor is an electrical device able to store electrical charge between
two closely-spaced conductors (plates).Capacitance (C) measures how much charge (Q) is
stored for a given voltage (V), such that C = Q/V. Capacitance is inversely proportional to
the distance (d) between plates.In condenser mics, the front plate is the diaphragm which
vibrates with the sound. The charge (Q) is fixed, thus changes in the distance d between
plates result on changes of voltage (V).
Condenser mics can be extremely high quality. The diaphragm can be very light, rendering
a flat frequency response (with a small resonance peak at above 12kHz). Output of
condenser mics is much higher than for dynamic mics. High output makes it more robust to
noise.
To charge the capacitor a source of power is needed (usually phantom power - to be
discussed later in the course).An alternative to using a power source is to introduce a
permanent electrostatic charge during manufacture, resulting on the “electret” mic.Electret
microphones can be very small, high quality (back electrets) and cheap, e.g. Tie-clip TV
microphones.
Fig.3 Condenser microphone
Characteristics of microphones:
• Professional microphones have a low-impedance usually around of 200 ohms - this
enables the use of long leads.
• Another important characteristic is sensitivity, i.e. a measure of the electrical output (in
volts) per incoming SPL.
• Sensitivity is usually given in terms of a reference SPL, e.g. 94 dB or 1 Pascal (Pa).
• Condenser microphones (5-15 mV/Pa) are more sensitive than moving coils (1.5-3
mV/Pa) and ribbons (1-2 mV/Pa).
12. 12
• More amplification is needed for moving-coils and ribbons (which are thus more
susceptible to interference). Also, low-sensitivity mics need high-quality (low noise) amps
and mixers.
• All microphones generate some noise. This is usually expressed in “A-weighted” self-
noise (given in dBA).
• High-quality condenser and moving-coil mics achieve self-noise of 17-18dBA. Ribbon
mics’ noise can be of the order of 23dBA, which means that for quite signals low-noise
amps need to be used. A
self-noise in the region of 25dBA results in poor performance.
Directional Response :
1.Microphones are designed to have a directional response pattern. This pattern is
characterized by a polar diagram showing magnitude of the output (in dB) vs angle of
incidence .An omni-directional microphone picks up sound equally in all directions .This is
achieved by opening the diaphragm at the front and completely enclosing it at the back. At
high frequencies the wavelength is comparable to the size of the capsule, resulting in a loss
of gain off front center. Smaller capsules result in better high frequency performance.TV
tie-clip microphones are usually omni electrets.
Fig.4 Fig.5
2.Figure eight or bidirectional microphones have an output close to cos(θ), where θ = angle
of incidence. This directional pattern is mostly associated with ribbon microphones (open
both at the front and rear).The response is thus the result of the pressure difference between
diaphragm front and rear (which is why response is null at 90/270°) The long wavelengths
at low frequencies (resulting in small phase differences) cause a reduction of the output.
Because of the ribbon’s shape, ribbon mics have a better polar response when upright or
upside down, than when positioned horizontally.
13. 13
3.Cardiod microphones result from the combination of omnidirectional and bidirectional
patterns.Their output is close to 1 + cos(θ).They are unidirectional. The response is obtained
by leaving the diaphragm open at the front while using acoustic labyrinths in the rear to
cause differences of phase and amplitude in the incoming sound. Mid frequency response is
usually very good.
.
Fig.6 Fig.7
4. There are a number of specialized microphones such as so-called shotgun microphones
or parabolic microphones which are highly directional. A shotgun mic, example, is cardiod
with a long barrel with openings aimed at causing canceling phase differences.
CCD-CAMERA:
Camera captures the real image into electrical form.The transducer used in modern Cameras
is CCD chips.CCD = Charge Coupled Device. Replaces photographic film and
photomultiplier tubes. Consists of a thin silicon wafer divided into thousands (or millions)
of tiny light sensitive squares (photosites). Each photosite corresponds to an individual
pixel in the final image. Turns light (photons) into electrons (charge) – photoelectric effect
– analog device.Each photosite has a positively charged capacitor that attracts the electrons.
Uses movement of charge within the device. Output – voltage from each photosite
dependent on number of photons that penetrated the silicon surface. Output voltage
converted to a digital signal (electronics).Instead of taking a picture – records an
image.CCD chip was developed in 1969 by AT&T’s Bell Labs.
Working of CCD:
At beginning of exposure Capacitors are positively charged and disconnected (bias)
Shutter is opened Photons enter silicon crystal lattice and are absorbed – raising
14. 14
some electrons from a low-energy valence band to a high energy conduction band (in other
words, some electrons are liberated from their silicon atoms) .Electrons are attracted to
nearest positively charged capacitor – partially discharges capacitor (changes voltage).
Degree of discharge is proportional to number of photons that hit each photosite during the
exposure At end of exposure, the electrons at each photosite are passed to a charge-
sensing node, amplified, and passed to read-out electronics to be digitized and sent to the
computer.
For silicon – energy difference between valence (tightly bound electrons) and conduction
band (free electrons) is 1.1 ev. Only photons with energy greater than 1.1 ev will be
detected (11000 Angstroms, in the infrared).At shorter wavelengths, silicon becomes more
reflective, so photons never enter silicon crystal. Blue cut off is about 3000
Angstroms.CCDs are linear (# of electrons is proportional to number of photons) as long as
you don’t have too many electrons. Charge can leak from one photosite to the next if there
are too many electrons bleeding. Photosites are arranged in rows and columns. Size of
photosites varies.
Fig.8 Basic structure of CCD
15. 15
The output digital signal from CCD is stored in a memory chip and is sent to processor for
image processing.
Audio Mixer:
Audio are used to combine the input signal from various microphones units. The output
signal obtained is transmitted to distant station by transmitter.
Fig.10
Diagram shows the 3-channel sound mixer circuit using three Norton-opamps. The input
levels can be set by potentiometers P1 or P3. Furthermore, each input level can be trimmed
with the help of trimmers pots P4 to P6 to adapt each input to the source. The resistors at the
non-inverting inputs of the opamps work as DC bias and set the DC output at 50 percent of
the power supply for this powered audio mixer. All three input signals are summed by the
16. 16
fourth opamp A4 through the resistors R3, R7 and R11. The commom volume level is
cotrolled through the potentiometer P7.
You can switch an input channel on or off through the switches S1 and S3. An input
channel is turned off when its switch is closed. It is also possible to replace these
mechanical switches with transistor gates. By doing so, you can build an analog multiplexer
circuit that can be easily expanded by several inputs
TRANSMITTER:
"Transmitter" is a telemetry device which converts measurements from a sensor into a
signal, and sends it, usually via wires, to be received by some display or control device
located a distance away.
Fig.11 Transmitter
Above block diagram shows a frequency modulated transmitter.In frequency modulation
(fm) the modulating signal combines with the carrier to cause the frequency of the resultant
wave to vary with the instantaneous amplitude of the modulating signal. Figure shows you
the block diagram of a frequency-modulated transmitter. The modulating signal applied to a
varicap causes the reactance to vary.
17. 17
4. DETAILS OF PROJECT UNDERTAKEN
Introduction
A satellite is essentially a space-based receiving and transmitting radio. In other words, it
sends electromagnetic waves, carrying information over distances without the use of wires.
Since its function is to transmit information from one point on Earth to one or more other
points, it actually functions as a “radio-frequency repeater.”
A satellite receives radio-frequency signals, uplinked from a satellite dish on the Earth,
known as an Earth Station or Antenna1. It then amplifies the signals, changes the frequency
and retransmits them on a downlink frequency to one or more Earth Stations.
Basic Working of a Satellite Communication System
Two Stations on Earth want to communicate through radio broadcast but are too far
away to use conventional means.
The two stations can use a satellite as a relay station for their communication
One Earth Station sends a transmission to the satellite. This is called a Uplink.
The satellite Transponder converts the signal and sends it down to the second earth
station. This is called a Downlink.
Fig.12 Satellite communication system
18. 18
Frequency Bands and Capacity Allocation
1. Frequency Bands
Different kinds of satellites use different frequency bands.
L–Band: 1 to 2 GHz, used by MSS
S-Band: 2 to 4 GHz, used by MSS, NASA, deep space research
C-Band: 4 to 8 GHz, used by FSS
X-Band: 8 to 12.5 GHz, used by FSS and in terrestrial imaging, ex: military and
meteorological satellites
Ku-Band: 12.5 to 18 GHz: used by FSS and BSS (DBS)
K-Band: 18 to 26.5 GHz: used by FSS and BSS
Ka-Band: 26.5 to 40 GHz: used by FSS
2. Capacity Allocation
FDMA
Satellite frequency is already broken into bands, and is broken in to smaller channels in
Frequency Division Multiple Access (FDMA).
Overall bandwidth within a frequency band is increased due to frequency reuse (a frequency
is used by two carriers with orthogonal polarization).
The number of sub-channels is limited by three factors:
Thermal noise (too weak a signal will be effected by background noise).
Inter modulation noise (too strong a signal will cause noise).
Crosstalk (cause by excessive frequency reusing).
FDMA can be performed in two ways:
19. 19
Fixed-assignment multiple access (FAMA): The sub-channel assignments are of
a fixed allotment. Ideal for broadcast satellite communication.
Demand-assignment multiple access (DAMA): The sub-channel allotment
changes based on demand. Ideal for point to point communication
TDMA
Time Division Multiple Access breaks a transmission into multiple time slots, each one
dedicated to a different transmitter. TDMA is increasingly becoming more widespread in
satellite communication. TDMA uses the same techniques (FAMA and DAMA) as FDMA
does.
Advantages of TDMA over FDMA:
Digital equipment used in time division multiplexing is increasingly becoming
cheaper.
There are advantages in digital transmission techniques. Ex: error correction.
Lack of inter modulation noise means increased efficiency.
Elements of Satellite Communication
Essentially, a satellite system consists of three basic sections:
1. The uplink
2. The satellite transponder
3. The downlink
1. The Uplink Model (Uplink Transmitter):
An Earth station transmitter is designed to accept information signals of whatever kind
(including voice signals, radio or television broadcasts, and data), use them to modulate a
carrier, possibly add error detection or correction coding, and amplify and radiate the
modulated signal toward a satellite. This shows, for example, the elements that might
20. 20
constitute a satellite news gathering (SNG) uplink station
Fig.13 Uplink model
The primary component within the section of a satellite system is the earth station
transmitter. A typical earth station transmitter consists of an IF modulator, an IF to RF
microwave up-converter, a high power amplifier (HPA).The IF modulator converts the
input baseband signals to either an FM, a PSK or a QAM modulated intermediate
frequency. The up-converter (mixer and BPF) converts the IF to an appropriate RF carrier
frequency. The HPA provides adequate input sensitivity and output power to propagate the
signal to the satellite transponder. The HPA’s commonly used are klystrons and TNT’s.
2. The Satellite Transponder:
The circuitry in the satellite that acts as the receiver, frequency changer, and transmitter is
called a transponder. This basically consists of a low noise amplifier, a frequency changer
consisting a mixer and local oscillator, and then a high power amplifier. The filter on the
input is used to make sure that any out of band signals such as the transponder output are
reduced to acceptable levels so that the amplifier is not overloaded. Similarly the output
from the amplifiers is filtered to make sure that spurious signals are reduced to acceptable
levels. Figures used in here are the same as those mentioned earlier, and are only given as
an example. The signal is received and amplified to a suitable level. It is then applied to the
mixer to change the frequency in the same way that occurs in a super heterodyne radio
receiver. As a result the communications satellite receives in one band of frequencies and
transmits in another.
21. 21
In view of the fact that the receiver and transmitter are operating at the same time and in
close proximity, care has to be taken in the design of the satellite that the transmitter does
not interfere with the receiver. This might result from spurious signals arising from the
transmitter, or the receiver may become de-sensitized by the strong signal being received
from the transmitter. The filters already mentioned are used to reduce these effects.
Fig.14 Satellite transponder
Signals transmitted to satellites usually consist of a large number of signals multiplexed
onto a main transmission. In this way one transmission from the ground can carry a large
number of telephone circuits or even a number of television signals. This approach is
operationally far more effective than having a large number of individual transmitters.
Obviously one satellite will be unable to carry all the traffic across the Atlantic. Further
capacity can be achieved using several satellites on different bands, or by physically
separating them apart from one another. In this way the beam width of the antenna can be
used to distinguish between different satellites. Normally antennas with very high gains are
used, and these have very narrow beam widths, allowing satellites to be separated by just a
few degrees.
A transponder is a part of a satellite, which is a combination of transmitter and receiver. The
main function of transponder is frequency translation and amplification. Based on the
frequency translation process, there are three basic transponder configurations. These are
single conversion transponder, double conversion transponder and regenerative transponder.
The uplink signal is received by the receiving antenna. The received signal is first band
limited by Band Pass Filter (BPF), then it is routed to Low Noise Amplifier (LNA).
22. 22
The amplified signal is then frequency translated by a mixer and an oscillator. Here only the
frequency is translated from high-band up-link frequency to the low-band down link
frequency. The mixer output (down link signal) is then applied to BPF then it is amplified
by a High Power Amplifier (HPA). This down link signal is then transmitted to receiver
earth station through a high power transmitting antenna.
3. The Downlink Model (Downlink Receiver):
An earth station receiver includes an input BPF, an LNA and an RF to IF down converter.
Fig.15 Downlink model
The BPF limits the input noise power to the LNA. The LNA is a highly sensitive, low noise
device. The RF-to-IF down converter is a mixer, BPF combination which converts the
received RF signal to an IF frequency.
The most common frequencies used for satellite communications are 6/4 and 14/12 GHz
bands. The first number indicates the uplink (earth station-to-transponder) frequency and
the second number is downlink (transponder-to-earth station) frequency. Since C band is
most widely used, this band is becoming overcrowded. A typical C band transponder can
carry 12 channels, each with a bandwidth of 36 MHz.
23. 23
5. CONCLUSION
Industrial training was based on the topic “TV Transmitter, Studio Equipment, Earth Station
and their associated equipments”. I have learned different ways of communication and the
instruments used in the industry. I would like to conclude that I have gained some
knowledge which I cannot obtain from the books or references. The experience in the
industry during five weeks is valuable for me. I have learned to be responsible for my
position and be punctual.
With the help of all this knowledge, I will be able to work in an industry. I am very thankful
to Mr. Vivek D. Kasture (Training coordinator) for his valuable guidance.
24. 24
LIST OF FIGURES AND TABLES
List of Tables
Table.1 Transmitter DD National Page 10
Table.2 Transmitter DD News Page 10
List of Figures
Fig.1 Cross section of dynamic microphone Page 11
Fig.2 Ribbon microphone Page 11
Fig.3 Condenser microphone Page 12
Fig.4 Polar plot Page 13
Fig.5 Polar plot Page 13
Fig.6 Polar plot Page 14
Fig.7 Polar plot Page 14
Fig.8 Basic structure of CCD Page 15
Fig.9 Principle behind CCD chip readout Page 16
Fig.10 Audio mixer circuit Page 16
Fig.11 Transmitter Page 17
Fig.12 Satellite communication system Page 18
Fig.13 Uplink model Page 21
Fig.14 Satellite transponder Page 22
Fig.15 Downlink model Page 23
25. 25
REFERENCES
Microphones, VET-Entertainment, Freshwater Senior Campus
Bernd Girod, Information Systems Laboratory, Department of Electrical
Engineering, Stanford University
International Journal of Advanced Research in Computer Science and Software
engineering, Volume 2, Issue 1, January 2012
Djordje Mitrovic, University of Edinburgh