90 
Measuring Noise
Improving Phase Noise Measurements by Subtracting Signal Analyzer Noise
Figure 7-12  Measurement of Analyzer Noise
8 Subtract the noise from the 
DUT phase noise 
measurement using the 
Power Diff math function. 
a. Press Trace/Detector, Select Trace, 
Trace 3, Clear Write.
b. Press More, More, Math, Power 
Diff, Trace Operands, Operand 1, 
Trace 1, Operand 2, Trace 2.
Notice the phase noise 
improvement at 100 kHz 
offset between trace 1 
(yellow trace) and trace 3 
(magenta trace).
See Figure 7-13.
Step Action Notes