Owon PDS5022S User Manual page 37

User's Manual of OWON Colour Digital Storage Oscilloscope
Quick Tips
If desired, use the zoom feature to magnify the FFT waveform.
Use the default dBV RMS scale to see a detailed view of multiple frequencies, even if they have
very different amplitudes. Use the linear RMS scale to see an overall view of how all frequencies
compare to each other.
Signals that have a DC component or offset can cause incorrect FFT waveform component
magnitude values. To minimize the DC component, choose AC Coupling on the source signal.
To reduce random noise and aliased components in repetitive or single-shot events, set the
oscilloscope acquisition mode to average.
Term interpretation
Nyquist frequency: The highest frequency that any Real Time Digital Oscilloscope can measure is
exactly half of the sampling rate under the condition of no mistakes,which is called Nyquist frequency.
If under-sampling occurs when the frequency sampled is higher than Nyquist frequency, "False Wave"
phenomenon will appear. So pay more attention to the relation between the frequency being sampled
and measured.
NOTE：
In FFT mode ,the following settings are prohibited:
window
Fig.24 Hanning
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