hfc now Flashcards
What would happen if there was awidespread outage during the SuperBowl 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 problemthat 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 atleast two headends with full signalacquisition of all video programmingsources in a major market?
In case of an outage, there would still beanother headend that would keep thenetwork 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 thedistribution or primary hub?
High-speed routers Two-way service equipment
What process can be utilized to combinemultiple optical signals onto the samefiber?
Wavelength division multiplexing
What are used to combine and splitoptical wavelengths onto the single fiber?
Optical Filters.
Loose tube fiber
consists of a single strengthmember in the center surrounded by colorcodedbuffer tubes, which contain fibersthat are also color-coded. These buffertubes may be covered with a fiberglassyarn (Kevlar®), an armored jacket isplaced around the entire bundle, and ajacket covering the cable helps to keep itweatherproof.
Flex tube fiber
consists of buffer tubes surrounded by a fiberglass wrap and twosteel 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 strengthmembers, and a jacket.
Ribbon configuration fiber
is the same as uni-tube, except fibers arearranged side-by-side.
Ribbon stranded fiber
is similar to loose tube. However, ribbon-stranded ribbonfibers are contained in buffer tubes.
Patch Panel-Related fiber problem
This could includeimproperly installed connectors andjumpers, contamination of the connector,improper cable routing, or a localizedfailure.
System-Related fiber problem
This would usually be due to over or under-driving theoptical transmitter.
Installation-Related fiber problem
This type of failure would be due to causes such asimproper bending radius or a clamped cable
Construction-Related fiber problem
These failures would normally be due toconstruction and work-related activities. In the case of an aerial cable, it canalso be damaged by improper installation techniques, gunshots, fallingbranches, and automobile crashes, just to name a few.
Thisconnector offers a good balance betweenloss and reflections and is the mostcommonly used connector.
Standard Connector (SC)
This connector provides a notch-push andscrew-on connection. It is less frequently used but will be seen in someinstallations.
Ferruled Connector (FC)
This connector has a flat cut on the end ofthe fiber and any reflections may be directed back to the source. It providesthe best insertion loss but about 5 dB worse return loss.
UPC (Ultra Polish Connector)
It provides an angle cut of 8 to 12 degreeson the end of the fiber. The loss is low, but any reflections may be directedback 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 anew 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 thegreatest loss?
Cable.
What do we call a device in the CATV distribution that has a gain between itsinput 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 cascadeprogresses.
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 systemspecification. Tilt is linier in nature starting at the lowest frequency and gains as frequencyincreases.
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 inthe network. All subsequent measurements will be taken relative to that point. Typically used atthe 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 andtheir levels.
Directional Couplers
Any sweep response that falls within peak to valley limits and which matches the point ofnormalization 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 designatedinjection 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 measuringdevice to each other.
Telemetry Frequencies
What is reverse path noise?
The summation of all noise from all the amplifiers in the reverse path.
