1. A SEMINAR ON “SATELLITE DIGITAL RADIO”

2. CONTENTS SATELLITE RADIO SIRIUS SATELLITE RADIO WORLD SPACE
BASIC COMPONENT OF SATELLITE RADIO
XM SATELLITE RADIO
GROUND REPEATERS
THE SATELLITE RADIO RECEIVERS
TECHNOLOGY
FREQUENCY OF OPERATION
EARTH ORBITS

3. SATELLITE RADIO
Satellite radio is a subscriber based radio service that broadcast directly from satellites.
It is an advanced form of mobile radio service where one can receive compact disc quality music and other entertainment channels.
Even if the person is miles away from the radio station, the quality of the program is not affected

5. Sirius Satellite Radio
Operated in the United States and Canada
Provides 69 channels of music
65 channels of news, sports and entertainment
Broadcast 24 hours a day commercial free from three satellites

6. WorldSpace Based in Silver Spring
First stated by wanting to improve literacy in Africa
Covers Asia, Europe, and Africa
Licensed to serve Central and South America
AfriStar (serves Africa) and AsiaStar (serves Asia and Europe)
3 transmission beams; 50 channels each
WorldSpace satellite receivers are capable of receiving data at a rate of 128 kilobits per second (Kbps).

7. BASIC COMPONENTS OF SATELLITE RADIO
The three satellite radio systems:
Satellites
Ground Repeaters
Radio Receivers

8. XM Satellite Radio United States and Canada
73 music, 39 news, sports and entertainment, 29 regional traffic and weather, 23 play-by-play sports.
XM Radio uses two Boeing HS 702 satellites, appropriately dubbed "Rock" and "Roll," placed in parallel geostationary orbit, one at 85 degrees west longitude and the other at 115 degrees west longitude.
Geostationary Earth orbit (GED) is about miles (35,764 km) above Earth, and is the type of orbit most commonly used for communications satellites

9. GROUND REPEATERS:
Satellite radio reception, poses threats from weather, tall building_ and mountains that can potentially interfere with broadcasts.
To avoid the interference caused by tall structures, both Sirius and XM Radio are supplementing their satellite coverage with terrestrial transmitters, called ground repeaters.

10. THE SATELLITE RADIO RECEIVER:
Existing AM/FM car radio will not be able to receive satellite radio broadcasts.
Replacement of the radio with a 3-band capable receiver (AM, FM, Sirius or XM Satellite).

11. Technology 25 MHz in S band 2.3 GHz 2 multichannel operators
MHz (Sirius)
MHz (XM)
complementary terrestrial repeaters
to overcome effects of satellite signal blockage and multipath interference
AM/FM/SAT receivers
Spring 2006

12. FREQUENCY OF OPERATION
Digital radio is operated in a frequency range of between MHz (Mega Hertz).
This part of the radio spectrum is sometimes called Band III, or VHF, and was previously used for some television transmissions and by the military.
The central frequency for the BBC National Multiplex is MHz.

13. Satellite Radio vs. Others
Listening availability- SR very high, others are moderate to low
Sound Quality-SR high, AM=very low, FM=High
Variety-SR Highest, Variable due to economic factors

14. Earth Orbits

15. Orbits NGSO GSO Low Earth Orbits Height: 700-2000 km
Rotation Period: 90 min.
Time in LOS of
earth station: 15 min.
Medium Earth Orbits
Height: km
Rotation Period: 5-12 hrs.
Time in LOS of
earth station: 2-4 hrs.
Geostationary Orbits
Height:35,780 km
Rotation Period: 24 hrs.
Time in LOS of
earth station: 24 hrs.
Spring 2006

16. Geosynchronous Orbit (GSO)
Uses XM (85oW 115oW)
Communications (DBS, data)
Advantages
1 orbit per siderial day (23h56m) (geostationary)
wide coverage
Disadvantages
round trip latencies exceed .5 seconds
weak coverage
inadequate elevation angles at high latitudes
Congestion

17. Medium Earth Orbit (MEO)
Uses
Cellular telephone communications
GPS (global positioning system)
Advantages
antenna size and power are relatively modest and the latency is still small
Disadvantages
Proximity to Van Allen belt creates hazards to electronic systems

18. Low Earth Orbit (LEO) Uses Advantages Disadvantages
Data-communications (Little LEO)
Data-and-voice communications (Big LEO)
Advantages
Low power requirements
Short propagation delays
Disadvantages
Greater no. of satellites needed for coverage
Big LEO req’d to provide continuous service to US

19. CONCLUSION
It will be an intelligent communications device that will offer more services and conveniences than can be provided by conventional analog technology.
For the broadcaster, digital radio is not just a way to stay competitive with other forms of digital sound, but one that offers numerous new business opportunities as well.
It is a bright future for listeners and broadcasters alike: a future that truly promises to provide 'the best sound on the airwaves' for the world.

20. REFERENCES http://www.seminar.com/article/sdr_1.html,
digital radio.pdf  

21. THANK YOU....

22. QUERIES???