MODEL QUESTIONS (IPE PATTERN)

Which of the following frequencies will be suitable for beyond the horizon communication using sky waves?

Digital signals,
(i) do not provide a continuous set of values,
(ii) represent values as discrete steps,
(iii) can utilise binary system, and
(iv)can utilise decimal as well as binary system.
Which of the above statements are true?

Is it necessary for a transmitting antenna to be at the same height as that of the receiving antenna for line of sight communication? A TV transmitting antenna is $81 \mathrm{m}$ tall. How much service area can it cover if the receiving antenna is at the ground level? (The radius is taken as $6.4\times {10}^6$)

A carrier wave of peak voltage $12 \mathrm{V}$ is used transmit a message signal. What should be the peak voltage of the modulating signal in order to have a modulation index of $75 \%?$

A modulating signal is a square wave, as shown below:

The carrier wave is given by $c\left(t\right) =2 \sin \left(8\mathrm{\pi t}\right) \mathrm{volts}.$Sketch the amplitude modulated waveform.

A modulating signal is a square wave, as shown below,

The carrier wave is given by $c \left(t\right)= 2 \sin \left(8\pi t\right) \mathrm{volts}.$ What is the modulation index?

For an amplitude modulated wave, the maximum amplitude is found to be $10 \mathrm{V}$  while the minimum amplitude is found to be $2 \mathrm{V}$. Determine the modulation index, $\mu .$ What would be the value of $\mu$  if the minimum amplitude is zero volt?

Due to economic reasons, only upper side-band of an AM wave is transmitted, but at the receiving station, there is a facility for generating the carrier. Show that if a device is available which can multiply two signals, then it is possible to recover the modulating signal at the receiver station.