FFT Window Functions

The window type list for Perform FFT on Report includes:


Window Function

Preferred Use

Rectangular

A low dynamic range function offering good resolution for signals of comparable strength. Poor when signals have very different amplitudes. w(n)=1

Rectangular Window

Tri

A Bartlett window with the endpoints valued at zero.

Barlette Window

Van Hann

A moderate dynamic range function, designed for narrow band applications.

Van Hann Window Equation

Hann Window

Blackman

A high dynamic range function, with lower resolution, designed for wide band applications.

Blackman Window Equation

where a0 =(1-a)/2; a1=1/2; a2=a/2

 

Blackman Window

Hamming

A moderate dynamic range function, designed for narrow band applications. It minimizes the maximum sidelobe.

Hamming Window Equation

Hamming Window

Lanczos

The Lanczos window offers a windowed form of the infinite sinc filter, providing the central lobe of a horizontally stretched sinc, sinc(x/a) for -a £ x £ a.

Sinc or Lanczos Window

Weber

 

Welch

This approach applies a parabola-shaped window to the frequency domain data. It is based on the Bartlett method but splits the signal into overlapping segments, which are then windowed. The intent is to balance the influence of data in the center of the function.