EXFO OSA20 User Manual page 75

To define the PT Search parameters:
Search Settings
PT Threshold

Threshold value for the discrimination of peaks and troughs in the spectrum.
Default values:
OSA and PCT analysis mode: 0.5 dB

WDM, RLT and OFA analysis modes: 3 dB

SML analysis mode: 0.5 dB

MML and BBS analysis modes (not settable): 3 dB

Mode Threshold (WDM, OFA, PCT and RLT analysis modes only)

Rejected
The only peaks retained are the ones with power higher than:
[Max power]-[Mode Threshold].
Default value in WDM, OFA, PCT and RLT analysis modes: 20 dB
Default value in OSA and SML analysis modes (not settable): 100 dB
Auto Noise Threshold


measurement (over 10 points surrounding the point of interest) and deduces a
value of noise threshold, below which a peak or trough cannot be effectively
detected.
This input has been introduced due to the strong dependence of spectral noise to
detected power (see the following figure, in which Noise Level @1575nm is
represented by Calculation Threshold). This noise threshold is then added to the PT
threshold for the peak and trough search.

OSA20
Mode Threshold
peaks
(default): the algorithm automatically detects the localized RMS noise of the
: the algorithm does not filter the local noise.
Setting Up Peaks and Troughs Search
Detected Channels
Wavelength or Frequency
Analyzing Traces
67