AM was the first method used to transmit human speech over long distances. Its primary strength lies in its . Because the hardware required to transmit and receive AM signals is relatively inexpensive and easy to build, it became the global standard for the first half of the 20th century.
Despite its history, AM has clear limitations. Because it relies on changes in power, it is highly susceptible to . Lightning, power lines, and even household appliances create electrical "noise" that mimics changes in amplitude. This results in the characteristic static or hissing sound familiar to AM radio listeners. amplitude modulation
Furthermore, AM signals—specifically those in the medium-wave band—have a unique ability to travel long distances. At night, these waves can bounce off the Earth’s ionosphere, a phenomenon known as "skypath propagation," allowing a listener in one country to tune into a broadcast from thousands of miles away. The Trade-offs AM was the first method used to transmit