Raised-cosine filter

The raised-cosine filter is a filter frequently used for pulse-shaping in digital modulation due to its ability to minimise intersymbol interference (ISI). Its name stems from the fact that the non-zero portion of the frequency spectrum of its simplest form (${\displaystyle \beta =1}$) is a cosine function, 'raised' up to sit above the ${\displaystyle f}$ (horizontal) axis.