Amplitude modulation (AM) is commonly used in aviation for radio communication systems, particularly in the context of aircraft communications. Here are a few reasons why AM is utilized in aviation:
Efficient use of bandwidth: AM allows for efficient use of the available frequency spectrum. By modulating the audio signal onto a carrier wave using AM, multiple communication channels can be accommodated within a limited frequency range. This is important in aviation, where numerous communication channels are required for different purposes, such as air traffic control, pilot-to-pilot communication, ground control, and navigation aids.
Compatibility with existing equipment: AM has been widely used in aviation for many years, and much of the existing communication equipment, such as radios and transceivers, is designed to work with AM modulation. Therefore, using AM ensures compatibility and interoperability with the existing infrastructure and aircraft systems.
Relatively simple implementation: Compared to other modulation schemes like frequency modulation (FM) or digital modulation techniques, AM is relatively simple to implement and requires less complex circuitry. This simplicity makes AM modulation more cost-effective, easier to maintain, and less prone to technical issues, making it a practical choice for aviation applications.
Resilience to noise and interference: AM signals can withstand noise and interference reasonably well. In aviation, where radio communication may be subjected to various sources of noise and interference, such as atmospheric conditions, electrical interference, or distance-related signal degradation, the robustness of AM modulation can help ensure reliable communication.
It's worth noting that in recent years, aviation communication systems have been transitioning to digital modulation techniques, such as amplitude-shift keying (ASK), phase-shift keying (PSK), or frequency-shift keying (FSK). These digital modulation schemes offer better spectral efficiency and improved resistance to noise. Nonetheless, AM continues to be used in certain aviation applications where its characteristics and compatibility with existing infrastructure remain advantageous.