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प्रश्न
On radiating (sending out) an AM modulated signal, the total radiated power is due to energy carried by ωc, ωc – ωm and ωc + ωm. Suggest ways to minimise cost of radiation without compromising on information.
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उत्तर
Sideband frequencies: The AM wave contains three frequencies ωc, (ωc + ωm) and (ωc – ωm), ωc is called carrier frequency, (ωc + ωm) and ( ωc – ωm) are called sideband frequencies.
(ωc + ωm) = Upper sideband (USB) frequency
(ωc – ωm) =Lower sideband (LSB) frequency
Sideband frequencies are generally close to the carrier frequency.
Only side band frequencies contain information in amplitude modulated signal, [only (ωc+ ωm) and (ωc + ωm)].
Here, the total radiated power is due to energy carried by ωc, (ωc – ωm) and (ωc+ωm)
For reduction of the cost of radiation without compromising on information, ωc can be left and transmit the frequencies (ωc + ωm), (ωc – ωm) or both (ωc + ωm) and (ωc – ωm).
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संबंधित प्रश्न
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In amplitude modulation ______.
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- Extrapolate and predict the problems one can expect if more waves are to be modulated.
- Suggest solutions to the above problem. In the process can one understand another advantage of modulation in terms of bandwidth?
An audio signal vm = 20sin2π(1500t) amplitude modulates a carrier vc = 80 sin 2π (100,000t). The value of percent modulation is ______.
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The maximum amplitude for an amplitude modulated wave is found to be 12V while the minimum amplitude is found to be 3V. The modulation index is 0.6x where x is ______.
