Communication Systems

Match List I with List II .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-c3ow{border-color:inherit;text-align:center;vertical-align:top} .tg .tg-7btt{border-color:inherit;font-weight:bold;text-align:center;vertical-align:top} .tg .tg-0pky{border-color:inherit;text-align:left;vertical-align:top} List I List II A. Troposphere I. Approximate 65-75 km over Earth's surface B. E-Part of Stratosphere II. Approximate 300 km over Earth's surface C. F$_2$-Part of Thermosphere III. Approximate 10 km over Earth's surface D. D-Part of Stratosphere IV. Approximate 100 km over Earth's surface Choose the correct answer from the options given below :

Match List I with List II .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-c3ow{border-color:inherit;text-align:center;vertical-align:top} .tg .tg-7btt{border-color:inherit;font-weight:bold;text-align:center;vertical-align:top} .tg .tg-0pky{border-color:inherit;text-align:left;vertical-align:top} List-I List-II A. AM Broadcast I. 88-108 MHz B. FM Broadcast II. 540-1600 kHz C. Television III. 3.7-4.2 GHz D. Satellite Communication IV. 54MHz - 890MHz Choose the correct answer from the options given below :

A carrier signal C(t) = 25 sin(2.512 $\times$ 10¹⁰t) is amplitude modulated by a message signal m(t) = 5 sin(1.57 $\times$ 10⁸t) and transmitted through an antenna. What will be the bandwidth of the modulated signal?

In amplitude modulation, the message signal V_m(t) = 10 sin (2$\pi$ $\times$ 10⁵t) volts and Carrier signal V_C(t) = 20 sin(2$\pi$ $\times$ 10⁷ t) volts The modulated signal now contains the message signal with lower side band and upper side band frequency, therefore the bandwidth of modulated signal is $\alpha$ kHz. The value of $\alpha$ is :

Only 2% of the optical source frequency is the available channel bandwidth for an optical communicating system operating at 1000 nm. If an audio signal requires a bandwidth of 8 kHz, how many channels can be accommodated for transmission :

Amplitude modulated wave is represented by ${V_{AM}} = 10\,[1 + 0.4\cos (2\pi \times {10^4}t)]\cos (2\pi \times {10^7}t)$. The total bandwidth of the amplitude modulated wave is :

Choose the correct statement for amplitude modulation :

A sinusoidal wave y(t) = 40sin(10 $\times$ 10⁶ $\pi$t) is amplitude modulated by another sinusoidal wave x(t) = 20sin (1000 $\pi$t). The amplitude of minimum frequency component of modulated signal is :

A signal of 100 THz frequency can be transmitted with maximum efficiency by :

At a particular station, the TV transmission tower has a height of 100 m. To triple its coverage range, height of the tower should be increased to

Which of the following frequencies does not belong to FM broadcast ?

Choose the correct statement :

If a message signal of frequency 'f_m' is amplitude modulated with a carrier signal of frequency 'f_c' and radiated through an antenna, the wavelength of the corresponding signal in air is :

A message signal of frequency 5 kHz is used to modulate a carrier signal of frequency 2 MHz. The bandwidth for amplitude modulation is :

Consider telecommunication through optical fibres. Which of the following statements is not true?

This question has Statement - $1$ and Statement - $2$. Of the four choices given after the statements, choose the one that best describes the two statements. Statement -$1$ : Sky wave signals are used for long distance radio communication. These signals are in general, less stable then ground wave signals. Statement -$2$ : The state of ionosphere varies from hour to hour, day to day and season to season.

A radar has a power of $1kW$ and is operating at a frequency of $10$ $GHz.$ It is located on a mountain top of height $500$ $m.$ The maximum distance upto which it can detect object located on the surface of the earth (Radius of earth $= 6.4 \times {10^6}m$) is :

A signal is to be transmitted through a wave of wavelength $\lambda$, using a linear antenna. The length l of the antenna and effective power radiated P_eff will be given respectively as : (K is a constant of proportionality)

A telephonic communication service is working at carrier frequency of 10 GHz. Only 10% of it is utilized for transmission. How many telephonic channels can be transmitted simultaneously if each channel requires a bandwidth of 5 kHz ?