### Mathematical formulae used in Sonor

These are a few of the formulae used in Sonor.
**FIR filter:**

In Sonor, *n*=128, and a 20-coefficient FIR filter is calculated.

**Resampling:**

where <*n*> is the integer value of *n*.

**FFT:**

Sonor does not actually use FFT, it uses discrete cosine transform, or DCT for short, as it is more accurate:

*s *is a strength factor.

**Add frequency:**

*s* is the amplitude of the wave from 0.0 to 1.0. *f* is the frequency of the sample.