Chapter 2 121
Front-Panel Key Reference
Marker
NOTE Pressing Delta again moves the reference marker to the active marker 
position, so you can make delta measurements from differing reference 
points without having to turn off the markers and begin again.
NOTE The delta marker function permits signal-to-noise measurements 
provided the signal is a single spectral component (sinusoid). Place a 
normal marker on the signal, press 
Delta, place the delta marker in the 
noise, and activate 
Marker Noise (see below). The indicated amplitude 
difference is signal-to-noise/Hz.
Delta Pair 
Ref Delta
Enters a mode that allows adjustment of both the Ref (start) and Delta 
(stop) markers independently. Pressing 
Delta Pair, toggles between the 
reference and delta markers. The start marker number is indicated 
with a number and an R above the marker (for example, 1R) and the 
delta marker is indicated with a marker number. This mode is useful in 
functions such as 
Band Power. (For information on using this function 
while in segmented sweep, refer to “Interaction with Other Analyzer 
Functions” in the segmented sweep section of this chapter which begins 
on “Segmented” on page 197.)
Key Access: 
Marker 
NOTE Ref and Delta markers maintain their displayed x-axis location, but not 
their frequency values when you change a parameter that redefines the 
x-axis scale. Reset these markers when parameters such as Span or 
Center Freq are changed.
Span Pair 
Span Center
Enters a mode that allows adjustment of both the ref and delta 
markers. Pressing 
Span Pair, toggles between the span and center 
markers. The start marker number is indicated with a number and an R 
above the marker (for example, 1R) and the stop marker is indicated 
with a marker number. Adjusting the span changes the frequency 
difference between the two markers while maintaining the midpoint 
between the two markers at a fixed frequency. Changing the center 
changes the center point between the two markers while maintaining 
the frequency difference. This mode is useful in functions such as 
Band Power. (For information on using this function while in segmented 
sweep, refer to “Interaction with Other Analyzer Functions” in the 
segmented sweep section of this chapter which begins on “Segmented” 
on page 197.)
NOTE Span Pair is not available when FREQUENCY, Scale Type (Log) is 
selected.
Key Access: 
Marker