narrow frequency modulation (NFM)

Speech signals occupy a much smaller frequency spectrum than audio signals such as music.

For this reason, frequency mod ulation with a significantly reduced frequency deviation is used in certain radio technologies for phonic transmission, such as voice radio, radio microphones and amateur radio. This modulation technique is called Narrow Frequency Modulation (NFM), in contrast to Wide Frequency Modulation (WFM), which is used in VHF broadcasting and in other radio areas with music transmission. The frequency deviation of narrowband frequency modulation is less than 50 kHz.