A modulating signal is a square wave, as shown below, The carrier wave is given by c ( t ) = 2 sin ( 8 π t ) volts . What is the modulation index?

It can be observed from the given modulating signal that the amplitude of the modulating signal, A m = 1 V It is given that the carrier wave c ( t ) = 2 sin ( 8 π t ) Therefore, Amplitude of the carrier wave, A c = 2 V Time period of the modulating signal T m = 1 sec The angular frequency of the modulating signal is calculated as: ω m = 2 π T m ω m = 2 π rad / sec . . . . . ( i ) The angular frequency of the carrier signal is calculated as: ω c = 8 π rad / sec . . . . . ( ii ) From equations (i) and (ii), we get: ω c = 4 ω m μ = A m A c = 1 2 = 0 . 5 The modulation index is 0 . 5 .

A modulating signal is a square wave, as shown below: The carrier wave is given by c ( t ) = 2 sin 8 πt volts . Sketch the amplitude modulated waveform.

It can be observed from the given modulating signal that the amplitude of the modulating signal, A m = 1 V It is given that the carrier wave c ( t ) = 2 sin ( 8 π t ) Therefore, Amplitude of the carrier wave, A c = 2 V Time period of the modulating signal T m = 1 sec The angular frequency of the modulating signal is calculated as: ω m = 2 π T m ω m = 2 π rad / sec . . . . . ( i ) The angular frequency of the carrier signal is calculated as: ω c = 8 π rad / sec . . . . . ( ii ) From equations (i) and (ii), we get: ω c = 4 ω m The amplitude modulated waveform of the modulating signal is shown in the following figure,

Mention the frequency range of speech signals.

Speech signal are those which emerges from a speaker's mouth, nose and cheeks, is a one- dimensional function (air pressure) of time. The speech signal don't have much information to carry. So, their frequency range is low, 300 Hz t o 3100 Hz .

E M B I B E

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 16 - Communication Systems>Exercise>Q 11

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IMPORTANT

Earn 100

What should be the size of the antenna or aerial? How the power radiated is related to length of the antenna and wavelength?

Important Questions on Communication Systems

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IMPORTANT

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 16 - Communication Systems>Exercise>Q 12

Explain amplitude modulation.

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 16 - Communication Systems>Exercise>Q 13

A carrier wave of peak voltage

12 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 % ?

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IMPORTANT

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 16 - Communication Systems>Exercise>Q 14

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

The carrier wave is given by

c (t) = 2 \sin (8 π t) volts .

What is the modulation index?

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IMPORTANT

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 16 - Communication Systems>Exercise>Q 15

For an amplitude modulated wave, the maximum amplitude is found to be

10 V

while the minimum amplitude is found to be

2 V

. Determine the modulation index,

μ .

What would be the value of

μ

if the minimum amplitude is zero volt?

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 16 - Communication Systems>Exercise>Q 16

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.

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 16 - Communication Systems>Exercise>Q 17

Define modulation. Why is it necessary?

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 16 - Communication Systems>Exercise>Q 18

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