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.