Motorola PTP 400 Series User Manual

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The analysis produces four key metrics for each channel:

• Peak of Peaks
• Peak of Means
• 99.9% Percentile of the Means
• Mean of Means

Peak of Peaks:

is the largest peak interference measurement encountered during the

quantization period. This metric is useful for detecting large short duration spikes in the

interference environment.

Peak of Means:

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:

is the value of mean interference measurement for 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 affect on the mean of means.

Mean of Means:

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: Spectrum Management uses the 99.9% percentile as the prime interference

measurement. All subsequent references to interference level refer to this percentile

measurement.

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.

The arithmetic mean is the true power mean and not the mean of the values expressed in dBm.