Network Architecture (Ulearn Network Technician Core Skills)

Question 1

The point of origination for downstream optical signals and the destination for upstream optical signals.

Answer 1

Headend/Hub

Question 2

Point where optical fibers may be spiced or routed to various network destinations.

Answer 2

Fiber Enclosure

Question 3

Point of conversion from optical signal to RF signal and vice versa.

Answer 3

Node

Question 4

Steel wire used to support aerial HFC devices.

Answer 4

Strand

Question 5

Couples 60 vAC or 90 vAC to the coaxial cable for powering active HFC devices. AC and RF travel simultaneously on the same coaxial cable.

Answer 5

Power Inserter

Question 6

A passive RF-splitting device. Passes most of the RF power directly through while tapping off a small amount of RF power to a coupled port.

Answer 6

Directional Coupler, or DC

Question 7

Connects to the commercial power to provide the network with AC power

Answer 7

Power Supply

Question 8

Signal-amplifying devices used to compensate for the losses of the coaxial and passive devices in the network.

Answer 8

Amplifiers or Line Extenders

Question 9

Devices that provide access points for underground installations. They may contain taps, line extenders, or other devices.

Answer 9

Pedestals

Question 10

Used to supply the RF signal to the individual customer premises.

Answer 10

Taps

Question 11

Contains layer 0, layer 1, and layer 2 devices. Layer 0 and Layer 1 devices include regional or master headends and switch headend sites or primary hubs, as they are sometimes called. Layer 2 devices include metro technical sites or secondary hubs, as they are sometimes called.

Answer 11

Core Network

Question 12

Interfaces between the core network and individual subscribers. It contains layer 3, layer 4, and layer 5 devices. Layer 3 includes access fiber. Layers 4 and 5 include the copper twisted pairs, coaxial cable, and optical fiber that connect to individual subscribers.

Answer 12

Access Network

Question 13

High-performance devices used in applications where the RF signals must travel long distances to reach subscribers.

Answer 13

Trunk Amplifier

Question 14

As the network approaches the individual subscribers, it splits into multiple branches called

Answer 14

Feeders

Question 15

Produces multiple outputs with high signal levels that are required to feed the various branches of the feeder.

Answer 15

Bridger Amplifier

Question 16

Provide gain to compensate for the coaxial, splitter, and tap loss in the feeder portion of the network

Answer 16

Line Extender or LE

Question 17

Frequency-selective devices that separate the downstream frequency band from the upstream frequency band.

Answer 17

diplex filters

Question 18

Optical-to-electrical converters or O-to-E converters.

Answer 18

Optical Receiver

Question 19

Two types of lasers are used in the access portion of an HFC network.

Answer 19

Fabry Perot (FP) lasers and distributed feedback (DFB) lasers

Question 20

A small output current is produced by a photodiode when there is no light present at the input

Answer 20

Photodiode dark current

Question 21

Will act as the first stage of amplification of the RF signal. In this stage, the signal coming into the amplifier is balanced with the EQ and pad.

Answer 21

Preamp

Question 22

In this stage of the amplifier, the RF will experience the largest gain in power.

Answer 22

Inter-stage

Question 23

Type of amplifiers that were replaced by fiber optic cables

Answer 23

Distribution

Question 24

Noise caused by amplifiers and the random motion of electrons due to heat.

Answer 24

Thermal or Gaussian

Question 25

Three examples of distortions

Answer 25

Composite triple beat (CTB), composite second-order (CSO), and cross-modulation (XMOD)

Question 26

Refers to the reduction of signal amplitude.

Answer 26

Attenuation