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Why is amplitude modulation used ?

Amplitude modulation (AM) is a modulation technique widely used in communication systems for various reasons, providing advantages and fulfilling specific requirements in certain applications. Here are detailed explanations of why amplitude modulation is used:

  1. Efficient Use of Bandwidth:
    • Explanation: AM is more bandwidth-efficient compared to direct modulation techniques like frequency modulation (FM). In AM, the bandwidth occupied by the signal is proportional to the highest frequency in the modulating signal, making it suitable for voice and music transmission without requiring excessive bandwidth.
  2. Compatibility with Existing Receivers:
    • Explanation: AM has been in use for a long time, and there are numerous AM receivers worldwide. The compatibility of existing receivers makes AM an attractive choice for broadcasting, especially in regions where legacy equipment is prevalent.
  3. Simple Modulation and Demodulation:
    • Explanation: The process of modulating and demodulating an AM signal is relatively simple, making it cost-effective to implement in both transmitter and receiver circuits. This simplicity is advantageous for widespread adoption, especially in applications where cost is a critical factor.
  4. Long-Range Signal Propagation:
    • Explanation: AM signals have better long-range propagation characteristics, particularly in the medium-wave and short-wave bands. This makes AM suitable for broadcasting over long distances, making it a preferred choice for AM radio stations covering large geographical areas.
  5. Ease of Implementation:
    • Explanation: The implementation of AM technology is straightforward, requiring minimal circuit complexity. This simplicity is advantageous in scenarios where the design and maintenance of equipment need to be cost-effective and user-friendly.
  6. Robustness in Noisy Environments:
    • Explanation: AM signals can be more robust in noisy environments compared to some other modulation techniques. The information in an AM signal is carried in the amplitude variations, making it more resistant to certain types of interference.
  7. Voice and Music Transmission:
    • Explanation: AM is well-suited for transmitting voice and music signals. The variations in amplitude capture the nuances of these signals, providing faithful reproduction of audio content. This makes AM a common choice for broadcasting music and talk shows.
  8. Historical Legacy:
    • Explanation: The historical legacy of AM, dating back to the early days of radio, contributes to its continued use. Many radio stations, especially in the medium-wave band, have a long-established presence, and the familiarity of AM broadcasts persists in various regions.
  9. Military and Aviation Applications:
    • Explanation: AM is used in certain military and aviation communication systems. The simplicity of AM modulation/demodulation, along with its acceptable bandwidth efficiency for voice communication, makes it suitable for specific applications in these domains.

In summary, amplitude modulation is used for its bandwidth efficiency, compatibility with existing receivers, simplicity in modulation/demodulation, long-range propagation, ease of implementation, robustness in noisy environments, suitability for voice and music transmission, historical legacy, and applications in military and aviation communication.

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