Frekvensmodulerat

Frekvensmodulerat, often abbreviated as FM, is a method of encoding information onto a carrier wave by altering its frequency. This technique is widely used in radio broadcasting, specifically for transmitting audio signals. In FM, the frequency of the carrier wave is varied in proportion to the instantaneous amplitude of the modulating signal. This means that the higher the amplitude of the original audio signal, the higher the frequency deviation from the carrier, and vice versa.

The primary advantage of FM over other modulation techniques, such as amplitude modulation (AM), is its superior noise immunity. Because the information is encoded in the frequency rather than the amplitude, external noise, which often manifests as amplitude fluctuations, has a much smaller impact on the received signal quality. This leads to clearer audio with less static and interference. FM also allows for a wider bandwidth, which can accommodate higher fidelity audio signals.

The process of generating an FM signal involves a device called a voltage-controlled oscillator (VCO). The audio signal is fed into the VCO, which then adjusts its output frequency based on the input voltage. At the receiver, a demodulator circuit detects the frequency variations and converts them back into an audio signal. The effectiveness of FM broadcasting is evident in its widespread adoption for music and talk radio where sound quality is paramount.