Delta markers are marker pairs that measure 
the difference in frequency/time and amplitude 
between a reference marker and a delta marker.  
When delta markers are activated, the reference 
and delta marker appear at the position of the 
selected marker, or in the center of the display 
if the selected marker has not yet be activated. 
The marker measurement is located at the top 
of the display, under the “normal marker” 
measurement.  
> Select Marker[F1] and select a 
marker number. 
2.  Press [F2] to turn the selected marker on. 
3.  Press Delta[F4]>Delta[F1] to set the selected 
marker to the Delta type.