Chapter 2 71
Front-Panel Key Reference
Auto Couple
PhNoise Opt
Auto Man
Chooses the LO (local oscillator) phase noise behavior that is optimum 
for measurement accuracy. 
Key Access: Auto Couple
Auto  Allows the analyzer to automatically select an LO 
phase noise behavior that is optimum for the selected 
span and RBW. The 
Auto rules choose Fast Tuning 
whenever the span is 
>
10 MHz otherwise the 
Auto rules 
choose 
Optimize £(f).
Key Access: 
Auto Couple, PhNoise Opt Auto Man
Optimize £(f)
  Optimizes for LO phase noise. 
Key Access: 
Auto Couple, PhNoise Opt Auto Man
Optimize LO for Fast Tuning
  The LO behavior compromises phase noise 
within approximately 10 MHz of the carrier. This 
allows rapid measurement throughput when changing 
the center frequency or span.
Key Access: 
Auto Couple, PhNoise Opt Auto Man
Detector Auto Man
Selects a specific detector, or in Auto, picks the appropriate detector for 
a particular measurement.
When discussing detectors, it is important to understand the concept of 
a trace “bucket.” For every trace point displayed, there is a finite time 
during which the data for that point is collected. The analyzer has the 
ability to look at all of the data collected during that time and present a 
single point of trace data based on the detector mode. We call the 
interval during which the data for that trace point is being collected, 
the “bucket.” Thus a trace is more than a series of single points. It is 
actually a series of trace “buckets.” The data may be sampled many 
times within each bucket.
Selecting 
Detector (Auto) and BW/Avg, Average (On) changes the detector. 
The 
Auto choice depends on marker functions, trace functions, and the 
trace averaging function. If a marker function or measurement is 
running, the 
Auto choice of detector is either Average or Sample. When 
one of the detectors (such as 
Average) is manually selected instead of 
Auto, that detector is used regardless of other analyzer settings.
The 
Average detector displays the average of the signal within the 
bucket. The averaging method depends upon 
Avg Type selection (Video 
or RMS).
The 
Peak detector displays the maximum of the signal within the 
bucket.
The 
Sample detector displays the instantaneous level of the signal at 
the time of the sampling.