RIGOL DS6000 Series - Manual (Page 131)

6 To Make Measurements RIGOL
DS6000 User’s Guide 6-7
4. Set the Vertical Scale
In FFT measurement, the unit of the horizontal axis changes from time to
frequency. Use HORIZONTAL SCALE to set the scale and position of the
horizontal axis respectively.
The unit of the vertical axis can be dB or Vrms which display the vertical
amplitude in logarithmic mode and linear mode respectively. If you need to
display the FFT frequency spectrum in a relatively larger dynamic range, dB is
recommended. Press Scale to select the desired unit and the default is Vrms.
Use VERTICAL SCALE and HORIZONTAL SCALE to set the vertical
amplitude and position of the FFT frequency spectrum respectively.
Tips
 Signals with DC components or deviation would cause error or deviation of
the FFT waveform components. To reduce the DC components, set the
“Channel Coupling” to “AC”.
 To reduce the random noise and aliasing frequency components of
repetitive or single pulse, set the “Acquisition Mode” of the oscilloscope
to “Average”.