Correction factors

Multiplication of original data by a window has an impact on the amplitude of the signal in the spectral domain. Thus the amplitude of frequency peaks will not correspond to the amplitude of the oscillations of the original data.

Simcenter Amesim propose to use correction factor to compensate.

The coherent gain of a window can be computed like this:

Figure 7: Coherent gain

where w(t) is the window function

The Amplitude mode correction factor is the inverse of the coherent gain:

Figure 8: Correction factor in Amplitude

The Energy gain of a window can be computed like this:

Figure 9: Energy gain

The Energy mode correction factor is the inverse of the energy gain square root:

Figure 10: Correction factor in Energy

Using these formula, we can compute the two correction factors for all windows:

Figure 11: Window correction factors

Note

Note that Simcenter Amesim uses correction factor in Amplitude for FFT and Spectral map and correction factor in Energy for PSD.