RIGOL  Chapter 6 MATH and Measurements 
6-6    DS2000E User’s Guide 
the same window to view the frequency spectrum more clearly and to perform 
more precise measurement.  
Note: In FFT mode and when MATH is the active channel, you can also press 
HORIZONTAL 
  SCALE to switch between "Split" and "Full Screen".  
 
4.  Set Horizontal Position and Horizontal Scale   
The horizontal axis of the FFT operation results represents frequency and its unit 
is Hz. Use HORIZONTAL 
  POSITION and HORIZONTAL    SCALE to 
set the horizontal position and horizontal scale of the FFT frequency domain 
waveform respectively.  
Note: Setting the horizontal position can changing the center frequency of the 
FFT operation results indirectly. 
 
5.  Set the Vertical Unit 
Press Scale to set the vertical unit to dB or Vrms and the default is dB. dB and 
Vrms 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, dB is recommended. 
 
6.  Set Vertical Position and Vertical Scale 
Press 
 and   and use   to set the vertical offset and vertical scale of 
the FFT frequency domain waveform respectively.  
 
7.  Anti-Aliasing 
Press Anti-Aliasing to enable or disable the anti-aliasing function. 
 
8.  Label 
Press Label to define a label for the operation results. For the details, please 
refer to "
MATH Label". 
 
 
  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".