Scaled Time Domain Window (Not in Base Package)

Applies the selected window to the time-domain signal. Details  Example

	Waveform is the time-domain signal.
	window is the time-domain window to be used. 0 Uniform 1 Hanning 2 Hamming 3 Blackman-Harris 4 Exact Blackman 5 Blackman 6 Flat Top 7 Four Term Blackman-Harris 8 Seven Term Blackman-Harris 9 Low Sidelobe
	Windowed Waveform is the time-domain signal, multiplied by the scaled window.
	window constants contains the window constants for the selected window. The default values are set to those of the uniform window (no window). eq noise BW is the equivalent noise bandwidth of the selected window. You can use this value to divide a sum of individual power spectra of the power spectrum or to compute the power in a given frequency span. coherent gain is the inverse of the scaling factor applied to the window.

Scaled Time Domain Window Details

The Scaled Time Domain Window VI scales the result so that when the power or amplitude spectrum of the windowed waveform is computed, all windows provide the same level within the accuracy constraints of the window. The Scaled Time Domain Window VI also returns important window constants for the selected window. These constants are useful when you use VIs that perform computations on the power spectrum, such as the Power & Frequency Estimate VI and the Spectrum Unit Conversion VI.

Defining Equations

All cosine windows without scaling are defined by the following equation.

where , n is the number of elements in X, and m is the number of elements in the window coefficient array a[].

For this VI, the preceding equation is modified to include division by the coherent gain (cg), as shown in the following equation.

Coefficients and Window Parameters for the Different Window Types

This section provides information about the a coefficients and window parameters for each window type available in this VI. Each window type has the following window parameters:

• coherent gain (cg)
• equivalent noise bandwidth (enbw)
• 6dB bandwidth (6dB BW)

Example

Refer to the Sound Card Simple Spectrum Analyzer VI in the labview\examples\sound\sound adv.llb directory for an example of using the Scaled Time Domain Window VI.