tral density (PSD).

It is 1 if attribute ``scaling == 'psd'``.
The window can be scaled to a psd spectrum by using the method
`scale_to`.

See Also
--------
fac_magnitude: Scaling factor for to a magnitude spectrum.
scale_to: Scale window to obtain 'magnitude' or 'psd' scaling.
scaling: Normalization applied to the window function.
ShortTimeFFT: Class this property belongs to.
r;