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प्रश्न
Explain, with the help of a suitable diagram, the space wave mode of propagation. Give two examples in communication systems where this mode is used. What is the frequency range of these waves? Give reason for using this range of frequency.
उत्तर
A space wave travels in straight line from a transmitting antenna to a receiving antenna. They are used for transmitting frequency signals above 40 MHz. Space waves are used for line of sight communication as well as satellite communication. The propagation of signal through a space wave is shown below:
Space wave mode of propagation is used in:
(i) Television broadcast
(ii) Satellite communication
The frequency range for these waves is 40 MHz or above. The reason for using this range of frequency is that at frequencies above 40 MHz, the antennas are relatively smaller and can be placed at heights of many wavelengths above the ground.
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संबंधित प्रश्न
Draw a neat, labelled block diagram for a generalised communication system.
Name the essential components of a communication system.
The figure given below shows the block diagram of a generalized communication system. Identify the element labelled 'X' and write its function.
Write two basic modes of communication
Any device that converts one form of energy into another is termed as ______.
(A) amplifier
(B) transducer
(C) receiver
(D) demodulator
Explain the terms : Receiver in communication system
What is the line of sight communication?
Explain the basic concept of mobile telephoning.
Name the type of waves which are used for line of sight (LOS) communication. What is the range of their frequencies?
A transmitting antenna at the tope of a tower has a height of 20 m and the height of the receiving antenna is 45 m. Calculate the maximum distance between them for satisfactory communication in LOS mode. (Radius of the Earth = 6.4 × 106 m)
Mention the function of any two of the following used
(i) Transducer
(ii) Repeater
(iii) Transmitter
(iv) Bandpass Filter
