Question
Download Solution PDFWhich of the following modulations is used in India for radio transmission?
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFThe correct answer is option 3
AM & FM both are used in India for radio transmission.
Concept:
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FM |
AM |
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The amplitude of FM wave is constant. It is independent of the modulation index. |
The amplitude of AM wave will change with the modulating voltage. |
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Hence, transmitted power remains constant. It is independent of mf. |
Transmitted power is dependent on the modulation index. |
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All the transmitted power is useful. |
Carrier power and one-sideband power are useless. |
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FM receivers are immune to noise. |
AM receivers are not immune to noise |
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It is possible to increase noise further by increasing deviation. |
This feature is absent in AM. |
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Bandwidth = 2[Δf + fm]. The bandwidth depends on modulation index |
BW = 2 fm. It is not dependent on the modulation index. |
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BW is large. Hence, wide channel is required |
BW is much less than FM. |
Advantages of Frequency Modulation:
- Frequency modulation is also not affected by noise and interference.
- Any variation in signal level does not affect the output as long as the receiver can cope up with the signal level. This makes the FM ideal for two-way radio communication or mobile communication application.
- It is also easier to apply modulation at a low-level power stage of a transmitter.
Disadvantages of Frequency Modulation:
- FM doesn’t have as efficient spectral efficiency as some of the other modulation formats.
- The sidebands for frequency modulation transmission extend out to infinity.
- Frequency modulation has a little more complicated and slightly more expensive demodulator than the AM.
Advantages OF AM:
- It is simple to implement.
- It can be demodulated using a circuit consisting of very few components.
- AM receivers are very cheap as no specialized components are needed.
Disadvantages of AM:
- It is not efficient in terms of its power usage.
- It is not efficient in terms of its use of bandwidth, requiring a bandwidth equal to twice that of the highest audio frequency.
- It is prone to high levels of noise because most noise is amplitude-based and AM detectors are sensitive to it.
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