Elements of a Communication System

A device used for transmission of images scanned at a transmitting point and duplicated at a receiving point is

A device mounted on a communication satellite which receives, amplifies and retransmits signals' from earth stations is called

A message signal of 12 kHz and peak voltage 20 V is used to modulate a carrier wave of frequency 12 MHz and peak voltage 30 V. Calculate the (i) modulation index (ii) side-band frequencies.

What should be the length of dipole antenna for a carrier wave of frequency $5\times {10}^8\mathrm{Hz}$ ?

What should be the length of dipole antenna for a carrier wave of frequency $6\times {10}^{8}H\text{z}$ ?

The length of a dipole antenna for a carrier wave of frequency $6\times {10}^8\text{Hz}$ is ( take speed of EM wave $3\times {10}^8 \mathrm{m} {\mathrm{s}}^{-1}$ )

A transmitting antenna at the top of a hill has a height $72 \mathrm{m}$ and the height of the receiving antenna is $128 \mathrm{m}$. The maximum distance between them for satisfactory communication in LOS mode is

(Use Radius of earth $=6.4\times {10}^6 \mathrm{m}$)

We do not transmit low frequency signal to long distances because
(a) The size of the antenna should be comparable to signal wavelength which is unreal solution for a signal of longer wavelength.
(b) Effective power radiated by a long wavelength baseband signal would be high.
(c) We want to avoid mixing up signals transmitted by different transmitter simultaneously.
(d) Low frequency signal can be sent to long distances by superimposing with a high frequency wave as well.

Therefore, the most suitable option will be :

The TV transmission tower at a particular station has a height of $125 \mathrm{m}$. For doubling the coverage of its range, the height of the tower should be increased by

A radio transmitting tower is $50$ meters high and the receiving antenna is also of similar height. The maximum distance up to which a "line of sight" mode communication between the two would be possible is approximately (take the radius of the Earth to be $6400 \mathrm{km}$ )

For the elements given below,

(A) Transmitter
(B) Information source
(C) User of information
(D) Channel
(E) Receiver
Choose the correct sequence in which these are arranged in a basic communication system.

What is the name of the process of increasing the strength of a signal using an electronic circuit?

What is used for Ring Modulator?

 In TV transmission, sound signal is _____ modulated.

In TV transmission, picture signal is _____ modulated.

Modulation is done in _____.

Which type is used and preferred in digital logic circuits?

Examples of PCM waveforms are

 When pulse code modulation is applied to non-binary symbols we obtain waveform called as.

 AVC stands for _____