laser satellite communication

Communication Satellites - Communication satellites are normally geostationary satellites. They have devices called transponder which receive signals from an earth station and transmit them in different directions. The signals in the form of electro..

Communication satellites are normally geostationary satellites. They have devices called transponder which receive signals from an earth station and transmit them in different directions. The signals in the form of electromagnetic radiation are transmitted from t..

) use a similar mechanism. In the case of intercontinental telecommunication, two or more satellites are linked together. High frequency radio and submarine cable systems have been widely used for long- distance overseas telecommunications. The high frequency band from 3 MHz to 30 MHz has..

For global communication, a communication satellite should move..

The area of the Earth from which a satellite is visible increases with the altitude. So, satellites at higher altitudes give larger coverage. At altitudes below 10,000 km, the number of satellites required for global coverage would be excessive. At altitudes above 20,0..

Communication Systems..

The smallest lasers used for telephone communication over optical fibres have as their active medium a semiconducting gallium arsenide crystal about the size of a pin-hea..

The development of the laser has opened many avenues of investigation and improved many others. The important characteristics that have contributed to its usefulness in these many areas are tile coherence, monochromaticity and great intensity of its radiation. (i) The smallest lasers..

(in the ruby, at the desired frequency). Such an arrangement is called a Fabry-Perot resonator. Pumping process is carried with the help of flash tube. The spiral flash tube pumps light energy into the ruby in pulses, which are generated by the charge and discharge of a capacito..

How a Laser Works - The below figure shows schematically how a population inversion can be achieved so that laser action-or lasing us it is called can occur. Atoms from the ground state E 1 are "pumped" up to an excited state E 3 , for example by the absorption of light energy f..