Frekvenssimoduulaatio

Frekvenssimoduulaatio, often abbreviated as FM, is a method of encoding information onto a carrier wave by varying its frequency. This is in contrast to amplitude modulation (AM), where the amplitude of the carrier wave is varied. In FM, the amplitude of the carrier wave remains constant, while its instantaneous frequency deviates from the center frequency in proportion to the instantaneous amplitude of the modulating signal.

The concept of frequency modulation is fundamental to many modern communication systems, particularly in radio broadcasting. FM radio stations transmit audio signals using FM, which offers several advantages over AM, including a higher signal-to-noise ratio and greater resistance to interference. This results in a clearer, more pristine sound quality. The frequency deviation, which is the maximum change in frequency from the carrier frequency, is a key parameter in FM. It determines the bandwidth occupied by the FM signal.

The mathematical representation of an FM signal involves a carrier wave whose frequency is a function of the message signal. When the message signal is a simple sinusoid, the FM signal's frequency oscillates symmetrically around the carrier frequency. The rate of this oscillation is determined by the frequency of the message signal, while the extent of the oscillation is determined by the amplitude of the message signal. This technique is widely used not only for audio transmission but also in various other applications, including telecommunications, radar, and magnetic recording.