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Setting
up Compax3
C3I12T11
256
192-120113 N08 C3I12T11 - December 2010
4.4.9.5
Measurement of frequency spectra
In this chapter you can read about:
Functionality of the measurement .................................................................................. 256
Leak effect and windowing ............................................................................................ 257
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(see on page 251, see on page 249)
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Functionality of the measurement
Measurement of the spectral analysis
System S
2
Signal u(t)
Controller & Signal Pocessing
Steuerung & Signal-
Verarbeitung
Amplitude spectrum
Amplitudenspektrum
V(f)
C3-Software-
Oscilloscope
Upload
System S
1
During the spectral analysis of scanned signals with the aid of the discrete Fourier
transformation, a so-called frequency resolution (Df) results, Df being =fA/N,
independently of the scanning frequency (fA) and of the number of measurement
values used (N).
The spectra of scanned signals are only defined for frequencies, which are an
integer multiple of this frequency resolution.
Interpretation of the frequency spectrum