Polybench® for biosignals / reference 1.34.1 Applies a standard window function on input vectors.

# Window

## Overview

This operator applies a window function on the input vector. This is used when an FFT is applied on non-periodic data.

The type of window function can be chosen in the property WindowFunction.

## Operator ports

Input V: Specific sample type, see below.

Output V_f: Floating point value buffers

## Properties

WindowFunction
type: Select from the list
Select one of the standard window functions from the list.
Select one of those presets:
Hanning
Hanning window
Hamming
Hamming window
BlackmanHarris
Blackman-Harris window
Cosine
Cosine window
Gausian
Gaussian window

Caption
type: Word or phrase
The name of the object in the project. This name must not contain '.', '\$' nor '@' characters.

Documentation
type: See description
Optional documentation of this object. If this object is an operator, the Documentation text is displayed below the operator symbol.

## Details

This operator offers a number of well known and often used window filter functions.

Hanning
This window function uses the formula:
H = ( 1 - cos(2*PI*n / N) ) / 2

Hamming
This window function uses the formula:
H = 0.54 - 0.46 * cos(2*PI*n / N)

Gaussian
This window function uses the formula:
H = e ^ ( -0.5 * (a * (n - N/2) / N/2)^2)
with a being inversely proportional to sigma.

Blackman-Harris
This window function uses the formula:
H = 0.35875 - 0.48829 * cos(2*PI* n / N) + 0.14128 * cos(4*PI*n/N) - 0.01168 * cos(6*PI*n/N)

Cosine
This window function uses the formula:
H = sin(PI * n / N)

where n is the field position in the vector, and N is the length of the vector.

## Examples

Example: Window Example
This example shows how the window operator can be used. It decreases the spectral leakage. Different window function can be choosen.
Examples\DF0600152_001_Window_Exmp.xmc