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Ch. 1 * (Principles of Transmission) Flashcards Preview

RCDD > Ch. 1 * (Principles of Transmission) > Flashcards

Flashcards in Ch. 1 * (Principles of Transmission) Deck (153)
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0
Q

Alloying

A

Adverse effect

1
Q

Most common electrical conductors…

A

Fiber does not belong

2
Q

Advantages of stranded conductors

A

Except better transmission

3
Q

Another name for insulation

A

Dielectric

4
Q

North America standard

A

American Wire Gauge

5
Q

Teflon

A

Dupont

6
Q

Dielectric strength

A

Measures maximum voltage an insulation can withstand without breakdown

7
Q

Reason for twisting pairs

A

Minimize Crosstalk

8
Q

Mutual inductance

A

Magnetic field

9
Q

Direction of twists

A

Counter clockwise

10
Q

Where are high temperatures found?

A

Exterior building walls, ceiling spaces, mechanical rooms

11
Q

Types of shields

A

Fiber does not belong

12
Q

Braid

A

Good

13
Q

Foil

A

Excellent

14
Q

Shield effectiveness

A

Less than 20 dB = poor

More than 60 dB = excellent

15
Q

Braid/Magnetic Field rating

A

Poor

16
Q

Drain wires

A

Applied longitudinally

17
Q

Analog signal

A

Sign wave

18
Q

Range of human hearing

A

20-20,000 Hz

19
Q

Frequency of telephone circuits

A

300-3,400 Hz

20
Q

Wave

A

Sinusoidal

21
Q

Sinusoidal theory

A

Joseph Fourier

23
Q

Phase

A

Time

24
Q

One watt of power on your input and one milliwatt of power on your output - what is the total amount of power lost in dB?

A

30

25
Q

Telecommunications transmission system consists of three basic components:

A

Source
Medium
Receiver

26
Q

Speed of light

A

186,000

27
Q

Speed of cable

A

.56c - .74c

28
Q

Round-trip delay for satellites

A

.25

29
Q

Power source options for VoIP

A

Except “bridge”

30
Q

Digital signals

A

Discrete steps

31
Q

One cycle

A

360 degrees

32
Q

Sampling theory

A

Harry Nyquist

33
Q

Companding types

A

Mu-Law

A-Law

34
Q

Companding standard for U.S.

A

Mu-Law

35
Q

PCM

A

Pulse Code Modulation

36
Q

PCM

A

256

37
Q

OC1

A

ATM (STS-1)

38
Q

Encoding rate of STS–1

A

51.8 Mbps

39
Q

OC-3

A

ATM (STS-3)

40
Q

Encoding rate of STS–3

A

155 Mbps

41
Q

Transmission circuit classifications

A

Simplex
Half duplex
Full duplex
Except…

42
Q

Baseband analog signal types

A

Composite

Component

43
Q

Component format

A

RGB

44
Q

Resistive model

A

Teeth

45
Q

Inductive model

A

Rings

46
Q

10 milliwatt signal on input lead and 10 microwatt of noise in a 1,000’ run:

A

SNR = 20dB

47
Q

10BASE-T

10BASE-T4

A

4 Pairs

48
Q

Three parts comprising a simple telecommunications system:

A

Transmitter
Receiver
Medium

49
Q

Multimode wavelength

A

850

1300

50
Q

Single mode wavelength

A

1310

1550

51
Q

VCSEL

A

Vertical cavity surface emitting laser

52
Q

Factors for determining fiber type

A

Distance
Bandwidth
Active equipment

53
Q

OM1

A

62.5/125

54
Q

OM2

A

50/125

55
Q

OM3

A

50/125 (laser)

56
Q

OS1

A

Singlemode

57
Q

OS2

A

Singlemode (low water-peak)

58
Q

Frequency of category 3

A

16 MHz

59
Q

Frequency of category 5e

A

100 MHz

60
Q

Fiber dispersion

A

Picoseconds

61
Q

Classifications of fiber

A

Multimode

Singlemode

62
Q

Supported distance of 1 Gbps over multimode

A

1,804’

63
Q

Singlemode attenuation

A

.5dB - OSP

1dB - Inside Plant

64
Q

Channel continuation distance calculation:

A

of strands X .75 + .3dB

65
Q

Power penalty

A 
LED = 2dB
Laser = 3dB
66
Q

Repair margin

A

Two splices

67
Q

Connection loss

A

.75dB

68
Q

Four steps for converting analog signals to digital:

A

Filtering
Sampling
Quantizing
Companding

69
Q

OC-1

A

28 T1s

70
Q

OC-3

A

(3) OC-1s

71
Q

OC-12

A

(4) OC-3s

72
Q

WDM

A

Lenses

73
Q

DS1

A

T1

74
Q

DS1C

A

Bonded T1

75
Q

OC-1

A

DS3

76
Q

Splice loss

A

.3dB

77
Q

Common electrical conductors

A

Copper
Copper covered steel
High-strength copper alloys
Aluminum, silver and gold

78
Q

Used for reference value

A

Annealed copper

79
Q

Sets the standard for comparing conductivity of other metals

A

Copper

80
Q

Corrosion resistance of high-strength alloy

A

Poor

81
Q

Oxidation resistance of aluminum

A

Poor

82
Q

Advantages of solid conductors

A

Less expensive
Less complex terminations
Better transmission performance

83
Q

Lower dielectric =

A

Better transmission performance

84
Q

Common insulation types

A

PVC - polyvinylchloride

PE - polyethylene

85
Q

Insulation used for low smoke (better performance)

A

FEP - flourinated ethylene propylene (Teflon)

ECTFE - ethylene clorotriflouroethylene (halar)

86
Q

Neoflon

A

Daikin

87
Q

Halar

A

Solvay Solexis

88
Q

Lowest dielectric insulation

A

FEP

89
Q

Dielectric constant of air

A

1.0

90
Q

Dielectric constant (def.)

A

Ratio of capacitance between insulated conductor and uninsulated conductor in air

91
Q

Insulation resistance (IR)

A

The longer the cable the less the IR (insulation resistance)

92
Q

Capacitance unbalance

A

Electric field coupling

93
Q

Temperature for balance twisted-pair cables

A

Attenuation increases above 68°

94
Q

Shields reduce ___

A

Radiated signals
EMI
Effects of electrical hazards

95
Q

Types of shields

A 
Braided
Spiral wrapped
Foils
Hybrids
Metal tubes
96
Q

Best shield

A

Conduit (metal tube)

97
Q

Non-grounded shield

A

Effectiveness is reduced

98
Q

3 dB =

A

Halving or doubling the power ratio

99
Q

Max transmission occurs when ___

A

Transmitting/receiving device have:

  • same load
  • same impedance
100
Q

Loading coils

A

Improves speech quality

101
Q

D loading

A

4495’

102
Q

H loading

A

6004’

103
Q

Codecs

A

Conversion of speech

104
Q

Baud

A

Modem

105
Q

BRI

A

160 Kbps

106
Q

STS

A

Synchronous Transport Signal

107
Q

Bipolar alternate mark inversion

A

AMI (graphic looks like a heartbeat)

108
Q

Biphase Manchester

A

Graph looks like Manhattan building’s skyline

109
Q

Synchronous

A

Single master clock

110
Q

HDSL

A

High bit rate DSL (2 pair)

111
Q

SDSL

A

Symmetrical DSL (1 pair)

112
Q

Electrical conductor (def.)

A

Any material that can carry an electric charge

113
Q

RF Carrier

A

TV channel

114
Q

Traditional video transport medium

A

Fiber

Coax

115
Q

NVP (nominal velocity propagation)

A

Stated as a percentage of the speed of light

116
Q

Delay skew

A

45 nanoseconds

117
Q

Return loss

A

Power of reflected signal

118
Q

Impedance mismatch

A

Signal reflections (echo)

119
Q

Attenuation to Crosstalk Ratio (ACR)

A

Minimum NEXT - Maximum Attenuation

120
Q

Impedance matching device

A

Balun

121
Q

EIA 232-F

A

150’

122
Q

DS1 distance

A

4920’

123
Q

Frequency of category 6

A

250 MHz

124
Q

Frequency of category 6a

A

500 MHz

125
Q

PSEC

A

Picoseconds

126
Q

Visible light

A

400-700 microns

127
Q

Attenuation of light

A

Visible – higher

Infrared – lower

128
Q

Wavelength for suitable communications

A

Window

129
Q

Mechanical splice

A

Temporary

130
Q

Fusion splice

A

Permanent

131
Q

Inventor of ethernet

A

Metcalf

132
Q

Lenses

A

Refract light

133
Q

Multimode loss

A 
850 = 3.5 dB
1300 = 1.5 dB
134
Q

Multimode characteristics

A

Chromatic and modal dispersion

135
Q

TDM

A

Combines multiple streams/signals

136
Q

Methods of encoding

A

Manchester

AMI

137
Q

Private line

A

600 Ohms

138
Q

Central office

A

900 Ohms

139
Q

Phenomenon

A

Echo

140
Q

Solid wall metal tube =

A

Conduit

141
Q

Pair to pair capacitance unbalance

A

Electrical field

142
Q

Bandwidth can be expressed as ___

A

PSACR > 0

143
Q

Average splice loss for singlemode mechanical splice

A

.10 dB

144
Q

Fiber transmitter power measured in ___ or ___

A

dBm or mW

145
Q

Fiber transmission change in intensity

A

Modulation frequency

146
Q

VDSL

A

ATM

147
Q

Propagation of balance twisted-pair depends primarily on ___

A

Dielectric materials surrounding conductors

148
Q

Transmission systems designed for analog are ___ w/ digital

A

Not efficient

149
Q

Encoding

A

Manchester
Differential Manchester
Bipolar alternate mark inversion (AMI)
Except “pulse coding”

150
Q

Range of wavelengths

A

Spectral width

151
Q

Numerical aperture value of OM1

A

0.275

152
Q

Multimode and singlemode connector parts are ___

A

Compatible

153
Q

Minimum system loss for fiber

A

Excess system gain over receiver dynamic range

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