welch

Welch windowing function.

Syntax

welch(vec_expr)

Argument

vec_expr
A valid vector expression.

Example

Curve Math Vectors Results
x = c1.x

y = fftmag(welch(c1.y))

 A curve is created which is the original curve windowed using the Welch window function.

A plot of this example is shown below:

Figure 1.


Each of the markers indicates where the plot has crossed the axis (zero-line).

Comments

The resultant vector is vec_expr multiplied by the Welch windowing function. This function is given by:



where w is the windowing function and N is the number of elements of vec_expr. Windowing functions are normally used in conjunction with frequency operations. A Welch windowing function is shown below.

Figure 2.


The resulting curve is power-normalized, in other words, the root mean square (RMS) of the original curve equals the RMS of the resulting curve. The mean is subtracted from the input before windowing in order to eliminate DC bias.