User Manual
Chapter 2 Front Panel Operation  RIGOL 
User’s Guide for DSA800 Series   
2-3 
Center Freq 
Set the center frequency of the current channel. Press this key to switch to center 
frequency/span input mode. The center frequency and span values are displayed 
at the lower left and right sides of the grid respectively. 
Key Points: 
  The start and stop frequencies vary with the center frequency when the span 
is constant. 
  Changing the center frequency horizontally shifts the current channel and the 
adjustment is limited by the specified frequency range. 
  In Zero Span mode, the start frequency, stop frequency and center frequency 
are always the same. If one is changed, the others are updated to match. 
  You can modify this parameter using the numeric keys, knob or direction keys. 
Refer to “Parameter Setting” for more details. 
Table 2-1 Center Frequency 
Parameter  Explanation 
Default 
3.75 GHz 
Range* 
0 Hz to 7.5 GHz 
Unit 
GHz, MHz, kHz, Hz 
Knob Step  Span > 0, step = Span/200 
Span = 0, step = RBW/100 
Min = 1 Hz 
Direction Key Step  CF step 
Note: *The range is from 50 Hz to (7.5 GHz-50 Hz) in non-zero span. 
Start Freq   
Set the start frequency of the current channel. Press this key to switch to 
start/stop frequency input mode. The start and stop frequencies are displayed at 
the lower left and right sides of the grid respectively.  
Key Points: 
  The span and center frequency vary with the start frequency. The change of 










