Chp 1

Question 1

Solid conductor Advantage

Answer 1

Price
Conductivity at high frequency
Resistance
Less complex termination systems

Question 2

Stranded conductor advantage

Answer 2

Flexibility

Less prone to damage (during termination, and over lifetime of flexing)

Question 3

Most common conductors in ICT

Answer 3

Copper
Copper clad steel
Copper Alloy
Aluminum

Question 4

Conductor used for electrical utility distribution, why

Answer 4

Aluminum
Lightest conductor with 60% conductivity. 
Other characteristics; 
Good: ductility, corrosive resistance 
Poor: oxidative resistance
Weight: approx 1/3 of copper
Tensile strength: < 1/3 of copper
Solderability: requires special techniques

Question 5

Conductor for self supporting cable

Answer 5

Type & Application:

Copper clad steel, for aerial drops

Question 6

Strongest conductor type

Answer 6

Type & application:
High strength alloys
used in aerospace and computer to meet specific characteristic requirements

Question 7

Composite conductors

Answer 7

Type & Application:
Pourable mixture to cure in cast/casing for embedded conductor applications.
ICT use: DONT. Trash it, and use other conductors if provided with equipment

Question 8

Insulators used for plenum

Answer 8

PVC

Question 9

Insulatior properties

Answer 9

Dielectric strength
IR (insulator resistance)
Dielectric constant
Dissipation factor

Question 10

Desired dissipation factor

Answer 10

Low.
This factor increases with signal frequency, and esp. concerning in MHz range (loss due to thermal exchange from “microwaves”)

Question 11

Desired Dielectric strength

Answer 11

high

Question 12

Desired dielectric constant

Answer 12

low, generally

Question 13

Desired IR

Answer 13

High

IR is determined by cable length (inverse relationship)

Question 14

Pair-to-pair capacitance unbalance is

Answer 14

a measure of the electric field coupling between two pairs if a differential voltage is applied on one pair and a differential noise voltage is measured on another pair in close proximity.

Question 15

Mutual inductance is

Answer 15

a measure of the magnetic field coupling between two pairs if a differential current is applied on one pair and a differential noise current is measured on another pair in close proximity.

Question 16

Cross-talk measured by

Answer 16

Mutual inductance and capacitance unbalance

Question 17

Tight twisting length

Answer 17

<12.7mm (.5”)

Question 18

Tight twist transmission effect

Answer 18

Preserves twists better, and therefore transmits signal more effectively

Question 19

Cable types using tight twists

Answer 19

CAT5e, 6, 6A & higher

Question 20

Tight twist physical effect

Answer 20

Cable structure maintains better

Question 21

Environmental design considerations

Answer 21

Max temperature

EMI sources

Question 22

Cable characteristics affected by temperature

Answer 22

What, trait
Conductor, resistance
Insulator, Dissipation factor
Insulator, Dielectric constant

Question 23

High temperatures likely to be found in

Answer 23

ceilings/plemuns
exterior walls
mechanical rooms
& cables using high levels of PoE

Question 24

Why temperature matters

Answer 24

Directly proportional to attenuation

Question 25

Attenuation is determined by mdeium's

Answer 25

Dielectric constant Dissipation factor Conductor resistance

Question 26

Design systems using the ____ temperature

Answer 26

potential highest

Question 27

Cabling standard reference for design

Answer 27

All twisted-pair cables are referenced in the cabling standards at 20 °C +/- 3 °C (68 °F +/- 5.4 °F). For adjustment purposes, the attenuation increase is 0.2 percent per degree Celsius for temperatures above 20 °C (68 °F) for screened cables, 0.4 percent per degree Celsius for all frequencies and for all temperatures up to 40 °C (104 °F), and 0.6 percent per degree Celsius for all frequencies and for all temperatures from 40 °C to 60 °C (104 °F to 140 °F) for all unscreened cables.

Question 28

Shielding cable

Answer 28

helps to maintain signal quality

Question 29

Often used with shields for the purpose of____

Answer 29

What, fill in blank | Drain wires, providing a conveinent means to ground shield & maintain continuity across perforations/braids/etc

Question 30

Phase is

Answer 30

What, units Reference of time in respect to the signals period Period is 360 degrees, i.e. 1/4 period = 90 degrees

Question 31

Sinusoidal signal described mathematically

Answer 31

``` formula v(t)=A*sin(2 pi f t + ø) A=amplitude f=freq t=time ø=phase ```

Question 32

Signal theory developed by

Answer 32

who | joseph fourier

Question 33

Fourier's Analog Signal Description

Answer 33

Any analog signal can be described by multiple sinusoidal signals. Each signal would be considered a component of the signal it represents. Collectively, these signals are referred to as the signals SPECTRUM. The difference across the frequencies which these signals have is the bandwidth of the signal.

Question 34

Used to express strength of signals

Answer 34

dB, dBm (dB referencing 1mW),dBW (dB referencing 1W)

Question 35

dB is

Answer 35

a ratio of power output to power input. | Often a standard unit is used to compare signals rather than using input

Question 36

Echo

Answer 36

When a signal encounters a discontinuity in the impedance of the medium carrying the signal, some of the signal power is relected back to the transmitter.

Question 37

Complex signals with many components use ___ instead of _____

Answer 37

Time, phase. | because phase can be described as delay in time

Question 38

The application of inductors, called _________, placed at intervals along a cable improves speech transmission quality.

Answer 38

loading coils

Question 39

Loading coils

Answer 39

* Compensate for the capacitance of a cable pair. | * Reduce the capacitive current loading in the range of audio frequencies.

Question 40

In telephony, Data speed transmission depends on

Answer 40

signal frequency (& medium characteristics: capacitive balance & mutual impedance)

Question 41

Higher frequencies travel _____ than low frequencies

Answer 41

faster

Question 42

Loading coils solve the speech quality issue but create a _______ issue

Answer 42

transmission delay

Question 43

Distance between loading coils determines the _____ frequency and have a _____ relationship

Answer 43

cut off | inverse

Question 44

Most common distances between loading coils

Answer 44

1.37km (for D loading) & 1.83km (for H loading)

Question 45

Issues in analog telephony

Answer 45

Issue, cause, solution, side effect Distortion, change of mediums/impedance & distance, loading coils, signal delay Echo, impedance change weakens signal cuz some bounces back, loading coils strengthen signal, signal delays

Question 46

IP Telephony

Answer 46

Uses data cabling Recommended dedicated jack so computer & phone dont compete Life safety telecom applications should use POE & UPS

Question 47

***Add cards with standards applicable to CAT3, CAT5, CAT6 from Table 1.17

Question 48

*** ADD Table 1.18 cable lengths/transmission rates & applications

Question 49

Although the cabling transmission parameters are complex, the inal result is that a transmission circuit should be cost-efective, meet applicable standards, and have:

Answer 49

• A uniform characteristic impedance that is matched to the equipment .• Low insertion loss/attenuation. • High SNR and available bandwidth. • Velocity of propagation that is relatively constant with frequency .• High NEXT and FEXT loss between pairs .• High NEXT and FEXT loss between pairs in adjacent cables and connectors .• High noise immunity.