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Noise Measurement Methodology
This section describes the proper methodology for conducting average and peak upstream
noise measurements. The procedures provided are designed to establish a consistent
methodology for obtaining the requested information during the characterization of the
installation site. The HP 8591C is the recommended spectrum analyzer to use for conducting
these measurements.
Average Upstream Noise Measurement
This section defines a procedure for taking the average upstream noise measurements
requested as part of the RF plant/HFC environment characterization. A statistical sample of
total nodes terminated at the installation site (10% recommended) should be taken. Table 8
provides the appropriate setup configuration settings for the HP 8591C spectrum analyzer.
Table 8: Average Noise Spectrum Analyzer Settings
1.
2.
3.
Upon completing the measurement, the analyzer display should resemble Figure 1 on
page 14.
Setting
Start Frequency
Stop Frequency
Resolution Bandwidth
Video Bandwidth
Scale
Internal Amplifier
Attenuator
Reference Level Offset
1
Reference Level
Number of Averages
1. This value may need to be adjusted for your particular test environment.
Connect the spectrum analyzer to the selected upstream signal at the upstream splitter
or at the CMTS upstream port.
Configure the spectrum analyzer per the values defined in Table 8.
Start the measurement.
Noise Measurement Methodology
Value
2 MHz
45 MHz
100 kHz
30 kHz
5 dB/div
On
0 dB
-28 dB
-5 dBmV
100
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