TAG: GS-3: SCIENCE AND TECHNOLOGY
THE CONTEXT: AM (Amplitude Modulation) and FM (Frequency Modulation) are techniques to encode information onto carrier waves.AM varies amplitude, while FM changes frequency. Signal modulation enables efficient communication over distances and minimises interference, with digital modulation offering enhanced resistance to noise.
EXPLANATION:
What is signal modulation?
Radio signals are broadcast using AM (or Amplitude Modulation) and FM (or Frequency Modulation). Electromagnetic waves are used to transfer data in both cases. The amplitude of the signal or carrier delivered is modulated (changing) depending on the information being sent, but the frequency remains fixed.
Modulation Types:
The modulation is of six various types:
- Amplitude modulation (AM):The amplitude of the data signal alters.
- Frequency modulation (FM):The frequency of the wave alters.
- Phase modulation (PM):The phase shift alters.
- Polarisation modulation:In an optical signal, the angle of rotation alters.
- Pulse modulation:The pulse of the wave shifts.
- Quadrate amplitude modulation (QAM)
Modulation:
- Basically, it is a process in a communication system. For communication, we need some fundamental elements.
- One is the high-frequency carrier wave, and the other is the information that has to be transmitted (modulating signal) or input signal.
- These are essential for communication which is done using a device from one place to another. All in all, we need the help of the communication system.
How does AM (Amplitude Modulation) work:
Amplitude modulation is a modulation technique where the amplitude of a carrier varies depending on the information signal. AM radio broadcast signals use lower carrier frequencies, which helps them travel long distances. Sometimes AM signals can be able to bounce off the ionosphere. The distance travelled by the AM is much larger than the FM.
- It contradicts the scenario where the signal’s frequency or phase is up for a change.
- Amplitude is the maximum height or distance that a wave reaches.
- It alters the strength of the signal wave.
- The amplitude modulation does not change the nature of the carrier waves. Rather, it adds a modulated wave with altered amplitudes from the carrier wave.
- Amplitude modulation is one of the requirements for communications, where the data has to be converted into electronic signal waves and vice versa.
How does FM (Frequency Modulation) work:
In this module, the carrier wave frequency is modified according to the signal that carries information. The radio signals have large bandwidth than AM radio signals, which helps to offer much better sound quality. Frequency modulation also enables to transmit stereo signals.
- It involves the altering of the frequency of the carrier wave.
- It is an important aspect of communications and broadcasting.
- On changing the frequency dimensions of the carrier wave, the data-carrying signals are changed into modulated signals.
What is the All India Radio (AIR):
- AIR, officially known since 1957 as Akashvani is the national public radio broadcaster of India and is a division of Prasar Bharati. It was established in 1936.
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