RIGOL DS1000B - Manual (Page 47)

RIGOL
User’s Guide for DS1000B Series 2-17
Key points for FFT
1. 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.
2. To reduce random noise and aliases components in repetitive or
single-shot events, set the oscilloscope acquisition mode to Average.
3. To display FFT waveforms with a large dynamic range, use the dBV
RMS
scale. The dBV
RMS
scale displays component magnitudes using a log scale.