# 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

Find more information about changing properties here: "Properties Viewer"WindowFunction

*type: Select from the list*

Select one of the standard window functions from the list.

Select one of those presets:

Hanning window

Hamming window

Blackman-Harris window

Cosine window

Gaussian window

**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.

For more information about the rules and usage of the Caption property, please refer to "Caption property - background and usage".

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*