FMmodulering

FM modulering, also known as Frequency Modulation, is a method of encoding information onto a carrier wave by varying its frequency. In FM, the amplitude of the carrier wave remains constant, while its frequency is altered in proportion to the instantaneous amplitude of the message signal. This technique is widely used in analog radio broadcasting, specifically for FM radio, due to its superior noise immunity compared to Amplitude Modulation (AM).

The process of FM starts with a carrier wave, which has a constant frequency and amplitude. A message signal, such as audio, is then used to modulate this carrier. When the message signal's amplitude increases, the carrier wave's frequency increases above its center frequency. Conversely, when the message signal's amplitude decreases, the carrier wave's frequency decreases below its center frequency. The extent to which the carrier frequency deviates from its center frequency is determined by the amplitude of the message signal. This deviation is crucial for the fidelity of the transmitted information.

At the receiver, a demodulator performs the reverse process. It detects the variations in the carrier wave's frequency and converts them back into the original message signal. Because FM receivers are designed to ignore amplitude variations, they are less susceptible to static and interference that often affect AM signals. This makes FM particularly well-suited for broadcasting music and other high-fidelity audio content. The bandwidth required for FM transmission is generally wider than for AM, which is a trade-off for its improved quality and noise reduction capabilities.