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प्रश्न
How is amplitude modulation achieved?
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उत्तर
Amplitude modulation is the process of varying the amplitude of the carrier signal in accordance with the amplitude of the message signal.
Amplitude modulated signals can be produced by adding the carrier signal with the message signal and passing the resultant signal through a square law device (eg: FET). Then the signal from the square law device is passed through band pass filter to allow only the signals centered at carrier frequencies to pass. The output of the band pass filter is power amplified and transmitted by the antenna.
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.
Explain any two factors which justify the need for modulating a low frequency base-band signal.
Write two advantages of frequency modulation over amplitude modulation.
Define amplitude modulation in a communication system.
In amplitude modulation ______.
A message signal of frequency ωm is superposed on a carrier wave of frequency ωc to get an amplitude modulated wave (AM). The frequency of the AM wave will be ______.
In amplitude modulation, the modulation index m, is kept less than or equal to 1 because ______.
- m > 1, will result in interference between carrier frequency and message frequency, resulting into distortion.
- m > 1 will result in overlapping of both side bands resulting into loss of information.
- m > 1 will result in change in phase between carrier signal and message signal.
- m > 1 indicates amplitude of message signal greater than amplitude of carrier signal resulting into distortion.
Compute the LC product of a tuned amplifier circuit required to generate a carrier wave of 1 MHz for amplitude modulation.
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 ______.
