Explain, why high frequency carrier waves are needed for effective transmission of signals.
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 and (ii) side-band frequencies.

Solution

High frequency carrier waves travel fast, approximately with the speed of light and are not interrupted by earth's atmosphere or surface. Hence, high frequency waves are used for transmission.

Numerical:

Here,

Frequency of message signal, v_{m} = 12 kHz P e a k v o l t a g e, E_{m} = 20 V

Frequency of carrier wave, v_{c} = 12 MHz = 12000 kHZ P e a k v o l t a g e o f c a r r i e r w a v e, E_{c} = 30 V

(i) Modulation index,

μ_{a} = \frac{E_{m}}{E_{C}} = \frac{20}{30} = 0.67

(ii) The side-bands frequencies are:

USB =

v_{c} + v_{m} = 12000 + 12 = 12012 kHz

LSB =

v_{c} - v_{m} = 12000 - 12 = 11988 kHz

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Wave Optics

Explain, why high frequency carrier waves are needed for effective transmission of signals.
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 and (ii) side-band frequencies.

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For Daily Free Study Material Join wiredfaculty

Wave Optics

Explain, why high frequency carrier waves are needed for effective transmission of signals.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 and (ii) side-band frequencies.

Some More Questions From Wave Optics Chapter

What is space wave propagation?

What is sky wave propagation?

What is the meaning of the term 'attenuation' in communication system?

What are the three basic units of a communication system?

Why are short waves used in long distance broadcasts?

What is the purpose of modulating a signal in transmission?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Explain, why high frequency carrier waves are needed for effective transmission of signals.
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 and (ii) side-band frequencies.