Declaration

THannKernel = class(TWindowedSincKernel)

Description

THannKernel implements a sinc filter modulated by a Hann (raised cosine) window function.

Mathematics

The Hann window function $w(x)$ for window radius $W$ is defined as:

$$w(x)=0.5+0.5\cos \left(\frac{\pi x}{W}\right)$$

The overall filter function is $f(x)=\text{sinc}(x)\cdot w(x)$ for $|x|\le W$.

References

• Ralph Beebe Blackman & John Wilder Tukey, "The measurement of power spectra from the point of view of communications engineering — Part I.", The Bell System Technical Journal. 37 (1), 1958.
• Hann function (Wikipedia)