oktavbåndfiltre

An oktavbåndfilter, also known as an octave band filter, is a type of frequency-selective filter used in signal processing and acoustic analysis. It divides a signal's frequency spectrum into a series of bands, where each band has a width that is one octave. An octave is a doubling of frequency. For example, if one band covers the frequencies from 100 Hz to 200 Hz, the next band would cover 200 Hz to 400 Hz, and so on. This logarithmic scaling of bandwidth is characteristic of octave band filters.

These filters are commonly employed in applications where analyzing the distribution of sound energy across different frequency ranges is important. This includes noise measurement and assessment, audio equalization, and psychoacoustic studies. By breaking down sound into octave bands, it becomes easier to understand how different frequencies contribute to the overall perceived loudness or character of a sound.

The center frequency of each octave band is typically chosen such that the geometric mean of its lower and upper frequencies is the center frequency. For example, in a third-octave band filter, the bandwidth is one-third of an octave. While full octave band filters are simpler, third-octave band filters provide finer resolution and are often preferred for more detailed spectral analysis. The output of an oktavbåndfilter is often a measure of the sound pressure level within that specific frequency band, which can then be visualized or further processed.