86  N9912A FieldFox User’s Guide  
o  Auto Sweep is set to the fastest sweep possible with the current settings.  
o  Man Enter a relative acquisition value between 1 and 5000, where: 
o  1 = Fastest sweep possible 
o  5,000 = Slowest sweep possible 
o  # is shown in front of the actual sweep time to indicate a manual setting. 
Some Detector and Video Bandwidth settings will raise the Auto Sweep 
Acquisition value greater than 1. In these cases, manually setting Sweep 
Acquisition lower than the Auto value may have NO effect. 
NOTE  Measurement speed specifications do NOT apply in Temperature Control Mode. 
Learn more on page 14. 
Zero Span Measurements 
When setting the frequency span to Zero, there is NO spectrum of frequencies to 
display, so the X-axis units becomes Time. The SA becomes like a tunable 
oscilloscope, with the center frequency being the frequency of interest.  This 
capability is useful for analyzing modulation characteristics, such as pulsed 
measurements. 
 
GSM signal, framed data format, timeslot 0 and 3 on. Sweep Time is set to 
approximately the frame interval. Press Single several times until the 
waveform section of interest is viewable and stable. Then markers can be 
used to measure the timeslot width and interval as shown. 
How to set Zero Span 
  Set Center to the frequency of interest  
o  then set Span to 0 Hz 
o  or select Zero/Last Span. Each key press toggles the frequency span 
between 0 Hz and the last specified frequency span.