HFC now! Flashcards
What would happen if there was a
widespread outage during the Super
Bowl or a major Pay-Per-View event?
Lots of very unhappy customers
Lost revenue
what does market health help?
By determining what affects the score, you can then identify the problem
that is common to the MAC addresses that are contributing to the score.
What is the impact to the customer of performing a reset in scout?
Temporary interruption of Xfinity Internet and Xfinity Voice service.
Why do you think we should have at
least two headends with full signal
acquisition of all video programming
sources in a major market?
In case of an outage, there would still be
another headend that would keep the
network in operation.
How can we minimize any fiber cut exposure between multiple headends?
Connect headends with a route-diverse fiber ring.
What is the second part of the headend and combining network?
The Distribution Hub
What equipment is located in the
distribution or primary hub?
High-speed routers
Two-way service equipment
What process can be utilized to combine
multiple optical signals onto the same
fiber?
Wavelength division multiplexing
What are used to combine and split
optical wavelengths onto the single fiber?
Optical Filters.
Loose tube fiber
consists of a single strength member in the center surrounded by colorcoded buffer tubes, which contain fibers that are also color-coded. These buffer tubes may be covered with a fiberglass yarn (Kevlar®), an armored jacket is placed around the entire bundle, and a jacket covering the cable helps to keep it weatherproof.
Flex tube fiber
consists of buffer tubes surrounded by a fiberglass wrap and two
steel strength members on each side molded into the jacket.
Uni-tube fiber
cable consists of larger buffer tubes with the fibers inside,
surrounded by fiberglass water block tape, armor, two steel strength
members, and a jacket.
Ribbon configuration fiber
is the same as uni-tube, except fibers are
arranged side-by-side.
Ribbon stranded fiber
is similar to loose tube. However, ribbon-stranded ribbon
fibers are contained in buffer tubes.
Patch Panel-Related fiber problem
This could include improperly installed connectors and jumpers, contamination of the connector, improper cable routing, or a localized failure.
System-Related fiber problem
This would usually be due to over or under-driving the
optical transmitter.
Installation-Related fiber problem
This type of failure would be due to causes such as
improper bending radius or a clamped cable
Construction-Related fiber problem
These failures would normally be due to
construction and work-related activities. In the case of an aerial cable, it can
also be damaged by improper installation techniques, gunshots, falling
branches, and automobile crashes, just to name a few.
This
connector offers a good balance between
loss and reflections and is the most
commonly used connector.
Standard Connector (SC)
This connector provides a notch-push and
screw-on connection. It is less frequently used but will be seen in some
installations.
Ferruled Connector (FC)
This connector has a flat cut on the end of
the fiber and any reflections may be directed back to the source. It provides
the best insertion loss but about 5 dB worse return loss.
UPC (Ultra Polish Connector)
It provides an angle cut of 8 to 12 degrees
on the end of the fiber. The loss is low, but any reflections may be directed
back in the cladding and not to the source.
APC (Angle Polish Connector)
This is the newer optical transport system that uses fibers in pairs with a
new LC and/or SC. They are different so that they can be plugged in sideby-
side.
LC
In a typical CATV distribution, what passive component contributes the
greatest loss?
Cable.
What do we call a device in the CATV distribution that has a gain between its
input and output?
It is called an “active device.”
The difference in RF signal level from the highest point on the sweep trace to the lowest point,
measured in dB. Limitations are generally set on how high this number can get as the cascade
progresses.
Peak-to-Valley
Progressive loss of signal level at a band edge.
Roll Off
Level of power difference between carriers in a given spectrum, usually determined by system
specification. Tilt is linier in nature starting at the lowest frequency and gains as frequency
increases.
Tilt
The actual sweep response of equipment prior to normalization.
Raw Sweep
A function of a sweep meter that ‘zeroes out’ the frequency response at a particular location in
the network. All subsequent measurements will be taken relative to that point. Typically used at
the node for both forward and return sweep, and sometimes used in troubleshooting.
Normalization
Used to insert (combine) the sweep points forward and return telemetry into the downstream/
upstream path and provide the sweep transceiver with a sample of the forward channels and
their levels.
Directional Couplers
Any sweep response that falls within peak to valley limits and which matches the point of
normalization reasonably well given its depth in cascade.
Normal Response
Signal loss that must be compensated for when utilizing probe locations on equipment.
Test Point Compensation
Previous stored normalization sweep of points within the system.
Sweep Reference
Total level (of a reference carrier, sweep etc.) injected in the return path, at a designated injection facility in the network (typically an active device).
Injection level
Upper and lower frequency limits of standard channel carrier/spectrum.
Band Edge
Used to combine more than one NBTC while sweeping multiple returns.
Combiners
Equipment used to receive data from more than one field unit simultaneously.
Return Receivers
A frequency (usually digital) that is used to connect via network more than one measuring device to each other.
Telemetry Frequencies
What is reverse path noise?
The summation of all noise from all the amplifiers in the reverse path.
