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प्रश्न
Frequencies in the UHF range normally propagate by means of:
(a) Ground waves.
(b) Sky waves.
(c) Surface waves.
(d) Space waves.
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उत्तर
(d) Answer:
Space waves
Owing to its high frequency, an ultra high frequency (UHF) wave can neither travel along the trajectory of the ground nor can it get reflected by the ionosphere. The signals having UHF are propagated through line-of-sight communication, which is nothing but space wave propagation.
संबंधित प्रश्न
Which of the following frequencies will be suitable for beyond-the-horizon communication using sky waves?
(a) 10 kHz
(b) 10 MHz
(c) 1 GHz
(d) 1000 GHz
Digital signals
(i) Do not provide a continuous set of values,
(ii) Represent values as discrete steps,
(iii) Can utilize binary system, and
(iv) Can utilize decimal as well as binary systems.
Which of the above statements are true?
(a) (i) and (ii) only
(b) (ii) and (iii) only
(c) (i), (ii) and (iii) but not (iv)
(d) All of (i), (ii), (iii) and (iv).
Whatis the difference between analogue signal and. digital signal?
Answer the following question :
Define 'bandwidth' and describe briefly its importance in communicating signals ?
Block diagram of a receiver is shown in the figure:
(a) Identify ‘X’ and ‘Y’.
(b) Write their functions.
Write any two factors which justify the need for modulating a signal ?
Draw a diagram showing an amplitude modulated wave by superposing a modulating signal over a sinusoidal carrier wave.
What do you mean by bandwidth of a signal? Give its importance.
The area of the region covered by the TV broadcast by a TV tower of 100 m height is (Radius of the earth = 6.4 × 106 m):
Long distance short-wave radio broadcasting uses
Broadcasting antennas are generally
What is meant by deviation in frequency of FM wave?
The audio frequency range is
