Triple-Play Service Deployment

Chapter 4: Troubleshooting the Copper Plant for IP Services
Another beneficial feature is Impulse Capture. This feature is
helpful to analyze the “signature” in amplitude versus time of the
captured impulse noise event. The Impulse Capture feature can be
set up to trigger on a detected impulse noise event which exceeds
the defined threshold and automatically, graphically captures the
impulse noise event for on screen viewing or storage and export
for later analysis.
Spectral Analysis of Wideband Noise
As mentioned previously, interference from sources such as other
digital services or AM or shortwave radio stations can reduce the
performance of a copper loop. Spectral analysis provides further
analysis and source identification once the presence of a noise
problem has been determined to be present. Spectral analysis
provides a graph of where noise disturbers exist in frequency and
amplitude across the spectrum of interest and aides in correlation
with potential interferences sources. For example, if a T1 circuit in
the same binder group is interfering with the xDSL service, a
spectrum analysis will show the noise pattern on the line and
allow the technician to overlay a mask of the frequency characteristics
for a T1 signal. If the characteristics match up with the
noise on the circuit, then the interferer can be identified as a T1
source. In this example, spectral analysis provides a quick and
simple means to identify the interference source.
ADSL1 interferer—100 ohm termination ADSL1 interferer—bridge mode
Figure 4.7 Spectral analysis with ADSL mask active
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