The radio broad casting in modulation process - Amplitude modulation-Frequency modulation-Phase modulation

Radio 



In a radio broadcasting station, the sound signals are converted into electric signals using a microphone. The frequency of the audio signal varies from 20 Hz to 20KHz. This low-frequency audio signal is superimposed on a high-frequency signal called a carrier wave. The resultant wave is called a radio wave or modulated wave. This process is called modulation. The modulated wave is radiated out in the form of an EM wave using an antenna. At the receiving end, the audio signal is extracted from the modulated wave.

 A high-frequency radio wave is used to carry the audio signal. On adding the audio signal to the carrier, any one of the characteristics namely amplitude frequency or phase of the carrier wave is changed in accordance with the intensity of the audio signal. This process is known as modulation.




There are three types of modulation processes used to change carrier waves listed below.


  •   Amplitude modulation

  •   Frequency modulation

  •   Phase modulation

Amplitude modulation


    It is the process by which the amplitude of the carrier wave is changed in accordance with the instantaneous value of the modulating voltage keeping the frequency and the phase angle constant.




A amplitude modulation only a small amount of audio power is required so it is a simple method but plate efficiency is low, and output power so that Frequency modulation is advanced. 


Frequency modulation

               It is a process by which the frequency of the carrier wave is changed in accordance with the instantaneous value of the modulating voltage keeping the amplitude constant. 


             The amount by which the carrier frequency is varied from its modulated value depends upon the amplitude of the modulating signal. The rate at which the variation takes place is determined by the frequency of the modulating signal.

            FM is more advantageous than AM. An AM wave distorted by man-made and natural noise AM leads to noisy reception but FM remove the noise.

Phase modulation
              
         It is a process by which the phase of the carrier wave is changed in accordance with the instantaneous value of the modulating voltage keeping the amplitude of frequency constant.
   
         The phase modulation generally uses a smaller bandwidth than FM. Phase modulation facilitates the highest transmission speeds on a given bandwidth.
The radio broad casting in modulation process - Amplitude modulation-Frequency modulation-Phase modulation The radio broad casting in modulation process - Amplitude modulation-Frequency modulation-Phase modulation Reviewed by knowledge people creators on January 09, 2019 Rating: 5
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