Agilent Technologies FieldFox N9912A - What Is a Peak

Data Analysis Features 143
 Track Peaks ON OFF When Track Peaks is ON, markers will find the new
peak with every sweep. While in this Mode, the markers can NOT be turned
OFF or moved.
 Find 3 Peaks Three markers are created and find the highest peaks (faults)
on the trace.
What Is a ‘Peak’
You define what the FieldFox considers a "peak" by setting the Peak Threshold
and Peak Excursion.
These two peak criteria settings are set individually for each trace and for each
mode (CAT, SA, or NA).
These settings do NOT survive a FieldFox or Mode Preset.
NOTE The Peak Threshold and Excursion settings are NOT available in DTF
measurements. To make these settings, create a non-DTF CAT mode
measurement, then change the measurement back to DTF.
How to set Peak Criteria
 Press Mrk ->/Tools.
 In CAT and NA modes:
o Then Peak Search.
 In SA mode:
o Then More
o Then Mkr Properties
 Then Peak Criteria
 Then select the following:
o Peak Threshold Minimum amplitude (dB). To be considered valid, the peak
must be above the threshold level. The valley on either side can be below the
threshold level. Default = –190 for CAT and NA Modes; –90 for SA Mode.
Note: CAT mode Loss measurements are displayed in positive values. In
these cases, the Peak Threshold setting is inverted. For example, Peak
Threshold = -20 will consider any peak that has less Loss than 20 dB to be
valid.
o Peak Excursion The vertical distance (dB) between the peak and the
valleys on both sides. To be considered a peak, data values must "fall off"
from the peak on both sides by the excursion value. Default = 0.5 dB for CAT
and NA Modes; 6 dB for SA Mode.
For example, the settings for the trace in the following image are:
o Threshold: –10 dB
o Excursion: 1 dB
o Scale = 1 dB / Division.