Communication systems practice · Medium

The galaxy in which we live is

The area of television telecast is made twice, the height of antenna will be changed as

An amplitude modulated voltage is expressed as
$e = 10\left( {1 + 0.8\,\cos \,2000\,\pi t} \right)\cos \,3 \times {10^6}\,\pi t\,{\text{volt}}$. The peak
voltage of carrier wave is

The source of time varying magnetic field may be
(A) a permanent magnet
(B) an electric field changing linearly with time
(C) direct current
(D) a decelerating charge particle
(E) an antenna fed with a digital signal
Choose the correct answer from the options given below.

Which of the following is not the main characteristic of laser beam?

Array gain of an antenna is

The maximum range, ${\mathrm{d}_{\mathrm{max}}}$ of radar is

Frequency range for microwaves is

In frequency modulation

A ground receiver station is receiving a signal at $100 \mathrm{~MHz}$, transmitted from a ground transmitter at a height of $300 \mathrm{~m}$ located at a distance of $100 \mathrm{~km}$. Then, $\left(N_{\max}=10^{12}\right.$ per $\left.\mathrm{m}^3\right)$

In the above question, if oscillator output is modulated by audio frequencies upto 10 kHz, the frequency range occupied by the side bonds will be

Remote sensing technique is used for

In amplitude modulation, the bandwidth is

Large band width for higher data rate is achieved by using

When ${\omega _m}$ is the modulation frequency in frequency modulation, the modulation index is proportional to

Assertion : In the transmission of long distance radio signals. short wave band issued.

Reason : In the shorter wavelength attenuation is very less.

A Television tower has a height of $75 \mathrm{~m}$. What is the maximum distance and area up to which this TV transmission can be received? Take radius of the earth as $6.4 \times$ $10^6 \mathrm{~m}$.

The physical sizes of the transmitter and receiver antenna in a communication system are

The ozone layer absorbs

The population inversion necessary for laser action used in solid state lasers is

To radiate EM signal of wavelength $\lambda$ with high efficiency, The antennas should have a minimum size equal to:

The output stage of a television transmitter is most likely to be a

Which fibers are less expensive and simple to construct?

The difference in the refractive index of the fiber core and fiber cladding in step-index fibers is typically

Height $h$ of transmitter antenna when $R$ is radius of earth to have range $d$ is

A 25 m long antenna is mounted on an antenna tower. The height of the antenna tower is 75 m.
The wavelength (in meter) of the signal transmitted by this antenna would be:

A message signal of frequency $10 \mathrm{~kHz}$ and peak voltage of 10 volts is used to modulate a carrier of frequency $1 \mathrm{~MHz}$ and peak voltage of 20 volts. The side bands are $1010 \mathrm{~kHz}$ and _____$\mathrm{kHz}$.

The characteristic impedance $\left( {{\mathrm{Z}_0}} \right)$ of free space is

A wave is represented as $e = 10\sin \left( {{{10}^8}t + 6\sin 1250t} \right)$ then the modulating index is

The T.V. transmission tower in Delhi has a height of $240 \mathrm{~m}$. The distance up to which the broadcast can be received (taking the radius of earth to be $6.4 \times 10^6 \mathrm{~m}$ ) is: