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प्रश्न
Write two advantages of frequency modulation over amplitude modulation.
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उत्तर
Following are the two advantages of frequency modulation over amplitude modulation:
1)Frequency modulation is more efficient than amplitude modulation because the amplitude of an FM wave is constant, irrespective of its modulation index. Thus, the transmitted power is constant. Also, all the transmitted power is useful in FM, whereas, in AM, most of the transmitted power goes waste in the transmitted carrier.
2) FM reception is quite immune to noise in comparison to AM reception, as noise is a form of amplitude variation in the transmitted signal. Thus, by using amplitude limiters in the FM receivers, we can almost eliminate the noise.
संबंधित प्रश्न
A signal of 5 kHz frequency is amplitude modulated on a carrier wave of frequency 2 MHz. What are the frequencies of the side bands produced?
Draw a block diagram of a detector for AM signal and show, using necessary processes and the waveforms, how the original message signal is detected from the input AM wave.
A modulating signal is a square wave, as shown
The carrier wave is given by `c(t) = 2 sin (8pit) "volts"`
(i) Sketch the amplitude modulated waveform
(ii) What is the modulation index?
How is amplitude modulation achieved?
The frequencies of two side bands in an AM wave are 640 kHz and 660 kHz respectively. Find the frequencies of carrier and modulating signal. What is the bandwidth required for amplitude modulation?
Explain any two factors which justify the need for modulating a low frequency base-band signal.
Why is frequency modulation preferred over amplitude modulation for transmission of music?
Draw the plot of amplitude versus ‘ω’ for an amplitude modulated wave whose carrier wave (ωc) is carrying two modulating signals, ω1 and ω2 (ω2 > ω1).
- Is the plot symmetrical about ωc? Comment especially about plot in region ω < ωc.
- 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?
The maximum and minimum voltage of an amplitude modulated signal are 60 V and 20 V respectively. The percentage modulation index will be ______.
A signal of 5 kHz frequency is amplitude modulated on a carrier wave of frequency 2 MHz. The frequencies of the resultant signal are ______.
