User's Guide Part 2

User Guide: PTP 600 Series Configuring the PTP 600
phn-0896_009v003
Feb 2010
UNDER DEVELOPMENT
6-23
The analysis produces three key metrics for each channel:
Peak of Means
This is the largest mean interference measurement encountered during the
quantization period. The peak of means is similar to the peak of peaks and is useful for
detecting slightly longer duration spikes in the interference environment.
99.9% Percentile of the Means
This is the value of mean interference measurement which 99.9% of all mean
measurements fall below, during the quantization period. The 99.9% percentile metric
is useful for detecting short duration repetitive interference that by its very nature has
a minimal effect of the mean of means.
Mean of Means
This is the arithmetic mean of the measured means during a quantization period. The
mean of means is a coarse measure of signal interference and gives an indication of
the average interference level measured during the quantization period. The metric is
not very good at predicting intermittent interference and is included to show the
spread between the mean of means, the 99.9% percentile and the peak of means.
NOTE
The arithmetic mean is the true power mean and not the mean of the values
expressed in dBm.
Spectrum Management uses the 99.9% percentile as the prime interference
measurement. All subsequent references to interference level refer to this
percentile measurement.
Statistical summary
The display of statistical measurement on the spectrum management page always
shows a statistical summary of all channel measurement. The statistical summary is
controlled by the Statistics Window attribute. This attribute defaults to a value of
twenty minutes, which means that the mean and percentile values displayed for each
channel are calculated over the 20 minute period. All channel decisions are made
using the values computed over the statistics window period.