RIGOL  Chapter 2 Front Panel Operation 
User’s Guide for DSA800/E Series 
  The readout resolution of the X-axis (frequency or time) is related to the span. 
For higher readout resolution, reduce the span. 
 
 
 
Delta 
 
One of the marker types. It is used to measure the delta values of X (Frequency or 
Time) and Y (Amplitude) between the reference point and a certain point on the 
trace. When selected, a pair of markers appears on the trace: Reference Marker 
(marked by a combination of the marker number and letter “R”, such as “1R”) and 
the Delta Marker (marked by the marker number, such as “1”). 
 
Key Points: 
  A reference marker will be activated at the position of the current marker if an 
active marker currently exists; or else both the reference marker and delta 
marker will be simultaneously activated at the center frequency.   
  The location of the reference marker is always fixed (both on the X-axis and 
the Y-axis); while the Delta Marker is active. You can use the numeric keys, 
knob or direction keys to change the location of the Delta Marker. 
  The frequency (or time) delta and amplitude delta between the two markers 
are displayed at the upper right corner of the screen.   
  There are two methods for defining a point as the reference point: 
a)  Open a “Normal” marker and locate it onto a point. Then, switch the 
marker type to “Delta”; at this time, this point is the reference point. You 
can modify the location of the delta point to achieve delta measurement.  
b)  Open a “Delta” marker and locate it onto a point. Then, reselect the 
Delta menu to locate the reference marker onto this point. You can 
modify the location of the delta point to achieve delta measurement.  
  When the Noise Mkr function under the Marker Fctn menu is activated, the 
result of the noise measurement will be corrected automatically and be 
normalized to 1 Hz.   
 
The application of “Delta” marker 
Measure the signal-noise ratio of single spectrum signal:  
Place the reference and delta Markers onto the signal and noise respectively, the 
amplitude in the measurement result is the signal-noise ratio.