Cambium PTP 670 Series, Руководство пользователя

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Chapter 7: Operation Spectrum Management
Page 7-50
Spectrum Expert example
In this example from a real-world link, shown in Figure 238 , the channel at 5740 MHz has been
selected for analysis.
The Spectrum display is based in the most recent 20 minute period. The height of the colored
bar in the selected channel shows that the 99.9th percentile of the interference is at
about -66 dBm. The orange color of the bar is a reminder that this level is above the
interference threshold of -85 dBm.
The upper bar of the “I” bar indicates the peak level of the interference. The lower bar of the
“I” bar indicates the mean level of the interference. The height of the “I” bar represents the
peak to mean ratio. In this channel, the peak to mean ratio is about 15 dB.
The red and black traces in the Timeseries plot show that the peak and mean interference
levels have been maintained at approximately constant levels over a period of about two
hours. Before that period, the interference level was considerably lower, at about -90 dBm.
In the Interference Waterfall plot, the selected time period is from 2 hours 20 minutes to 9
hours ago. The plot shows that interference occurred suddenly, across a broad band of
channels, shortly after the selected period, or about two hours ago, and that it has been
maintained at an approximately constant level since then. The Histogram plot shows that, prior
to the onset of interference, the interference level was consistently close to -90 dBm,
corresponding to the earlier part of the Timeseries plot.
Figure 238 Spectrum Expert, example 1
In
Figure 239 , the time period for the Histogram plot has been set to the most recent 20
minutes. The histogram shows that interference levels are distributed over the range of
approximately -74 dBm to approximately -54 dBm.