SA (Spectrum Analyzer) Mode  93 
 
Display line with annotation 
How to create and move a Display Line 
  Press Limit __8   
  Then Display Line OFF ON 
  Then enter a Y-axis value using the ▲|▼ arrows or the rotary knob, then press 
Enter. Or enter a value using the numeric keypad and press a suffix key or 
press Enter. 
Noise Marker 
For comparison purposes, electronic noise measurements are often displayed as 
though the measurement was made in a 1 Hz Res BW. However, making an actual 
measurement at a 1 Hz Res BW is impossible, and at 10 Hz, extremely slow. 
A Noise Marker, unique to SA Mode, mathematically calculates the noise 
measurement as though it were made using a 1 Hz bandwidth.  
Several data points (or ‘buckets’) are averaged together to calculate the Noise 
Marker readout.  To accurately measure noise, the Noise Marker should NOT be 
placed on, or too close to, a signal. The distance from a signal depends on several 
factors. To know if an accurate reading is being made, move the Noise Marker 
until consistent measurements are displayed in adjacent data points. 
In addition, when a Noise Marker is displayed, the Detection method is 
automatically switched to Average and PAvg is shown on the FieldFox screen. 
This occurs only when Detection is set to Auto. Learn more on page 91. 
With a Noise Marker present, the Res BW can be changed and the displayed noise 
floor will also change, but the Noise Marker readout will remain about the same.  
Noise Markers can be used like regular markers. A Noise Marker is distinguished 
from a regular marker by (1Hz) after the marker readout value. Learn more about 
regular markers on page 135. 
How to measure Noise with a marker  
  Press Marker to create or select a Normal or Delta marker to use to measure 
Noise.