User Manual

6 To Make Measurements RIGOL
DS4000 User’s Guide
6-7
HORIZONTAL SCALE to switch between “Split” and “Full Screen”.
4. Set the Vertical Scale
In FFT measurement, the unit of the horizontal axis changes from time to
frequency. Use HORIZONTAL SCALE and HORIZONTAL POSITION
to set the scale and position of the horizontal axis respectively.
The unit of the vertical axis can be dBVrms or Vrms which use logarithmic mode
and linear mode to display vertical amplitude respectively. If you need to display
the FFT frequency spectrum in a relatively larger dynamic range, dBVrms is
recommended. Press Scale to select the desired unit and the default is Vrms.
Press and and use to set the vertical position and amplitude 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”.