€h 01 - Principles Of Transmission Flashcards
1
Q
1-1 Metallica media – general
Volts, amp, ohm =
A
V, A, (ohm)
2
Q
1–2 electrical conductors
Common electrical conductor =
A
Except fiber or silver alloy (does not belong)
3
Q
1–2 description of conductors
Copper =
(2)
A
* Annealed copper
* 100% conductivity
4
Q
1–2 description of conductors
Alloy Copper =
A
Adverse conductivity
5
Q
1–3 solid conductor properties
Aluminum corrosion resistance =
Aluminum oxidation resistance =
A
* Good
* poor
* and vice versa for High-strength alloys
6
Q
1–4 solid vs stranded conductors
Advantages solid conductors =
A
Better transmission
7
Q
1–4 solid vs stranded conductors
Advantages stranded conductors =
(2) ^
A
* more flexible
* except better transmission (does not belong)
8
Q
1–5 AWG intro
AWG =
(2)
A
* American wire gauge
* accepted in North America
9
Q
1–5 insulation intro
PVC =
PE =
A
* Inside
* OSP
10
Q
1-5 insulation intro
a dielectric prevents direct contact =
(2)
A
* conductors
* a conductor and its environment
11
Q
1–6 insulation intro
Teflon trademark =
A
du Pont
12
Q
1–6 insulation intro
FEP trademark =
A
Daikin
13
Q
1–6 insulation intro
Halar trademark =
A
Solvay
14
Q
1–7 insulation electrical characteristics
Dielectric strength =
A
Measures maximum voltage
15
Q
1–8 balance twisted pair cable
Twisting pairs =
A
Minimize Crosstalk
16
Q
1–8 balance twisted-pair cable
Capacitance =
A
Electrical field
17
Q
1–8 balance twisted-pair cable
Mutual inductance =
A
Measure magnetic field
18
Q
1-8 balance twisted-pair cable
Pair twists =
A
Counterclockwise
19
Q
1–8 balance twisted-pair cable
Tight twists =
A
Preserves cable shape
20
Q
1–9 environmental considerations – temperature
Balance twisted-pair cable =
A
Increased attenuation above 68°F
21
Q
1–9 environmental considerations – temperature
High temperatures in =
(3)
A
* Exterior
* ceilings
* mechanical rooms
22
Q
1-14 types of shields
Shields =
A
Except fiber related, does not belong
23
Q
1-14 types of shields
Solid wall metal tubes (conduit) =
A
Best possible shield
24
Q
1–15 types of cable
Braid shield =
(2)
A
* audio = good
* magnetic field = poor
25
1–15 types of cable shields
Foil shield =
Excellent
26
1–15 shield effectiveness
Poor =
Excellent =
\* Less than 20 dB
\* more than 60 dB
27
1–15 shield effectiveness
Permeability =
Magnetic substance
28
1-16 drain wires
Shield not properly grounded =
Effectiveness reduced
29
1-16 drain wire applications
Drain wire =
Longitudinally
30
1-17 analog signal intro
Analog =
(2)
\* wave
\* example - sinusoid
31
1-18 sinusoidal signal
Human hearing =
20 Hz to 20,000 Hz
32
1-18 sinusoidal signal
Voice circuits =
300 to 3400 Hz
33
1-18 sinusoidal signal
Kilohertz =
1000 Hz
34
1-19 sinusoidal signal
Phase =
Time
35
1-19 sinusoidal signal
One cycle =
360 degrees
36
1-20 sinusoidal signal
Sinusoidal theorem =
Joseph Fourier
37
1-21 decibel (dB)
If you have one watt of power on your input and one watt on your output, what is the total amount lost in dB?
1000
500 = 3
250 = 3
125 = 3
62. 5 = 3
31. 25 = 3
15. 625 = 3
7. 8125 = 3
3. 90 = 3
1. 95 = 3
.97 = 3
** = 30dB**
^
38
1-22 decibel dB
Doubling power =
+3dB
39
1-22 decibel dB
1/2 power =
-3dB
40
1-22
Phenomenon =
Echo
41
1-23 telephony
Telecom transmission system =
(3)
\* source energy
\* medium to carry
\* receiving
42
1-23 telephony
Same load =
Same impedance
43
1-24 telephony
600 ohm impedance
Private line circuits
44
1-24 telephony
900 ohm impedance
Central office circuits
45
1-24 telephony echo
Speed of light =
186,000 mi/s
46
1-24 telephony echo
Speed of light in cable =
Or EM radiation slows
.56c to .74c
47
1-24 telephony echo
Satellite delay =
1/4 (0.25) second
48
1-25 telephony distortion
D loading =
H loading =
\* 4495ft
\* 6004ft
49
1-28 IP telephony
VIOP power source =
Except bridge, does not belong
50
1-29 digital signals
Digital signals =
Discrete steps
51
1-29 digital signals
Analog to digital =
4th step - companding
52
1-30 analog-to-digital
Analog sampling theorem =
Harry Nyquist
53
1-30 analog-to-digital
Companding =
(2)
\* A-law - Europe
\* Mu-law - United States, Canada, Japan
54
1-30 digital signal
PCM =
(2)
\* pulse code modulation
\* 256 levels
55
1-30 PCM
8000 samples/s x 8 bits / sample =
How many levels?
64,000 b/s
56
1-31 PCM
Codecs =
Conversion of speech
57
1-31 TDM
TDM =
(3)
\* Time Division Multiplexing
\* combines binary data
\* combines multiple data streams
58
1-33 TDM
E1 frame format
(8 b/x channel x 32 channels) x 8000 frame/s =
2.048 Mb/s
59
1-34 encoding
Encoding methods =
(2)
\* AMI = alternate mark inversion; bipolar
\* Manchester = +\- equal intervals; biphase
60
1-35 digital data to digital signal
Baud (rate) =
Modems
61
1-36 digital data to digital signal
Coding method STS-1 =
51.8 Mb/s
62
1-36 digital data to digital signal
Coding method STS-3 =
155 Mb/s
63
1-36 digital data to digital signals
Coding method:
ISDN (basic) =
ISDN (primary) =
\* 160 Kb/s
\* 1.544 Mb/s
64
1-41 types of transmission circuits
Transmission circuits =
(3)
\* Simplex = one direction
\* Half-duplex = both directions one at a time
\* full-duplex = both directions at the same time
65
1-42 asynchronous and synchronous transmissions
Asynchronous =
Start and stop
66
1-42 asynchronous and synchronous transmission
Synchronous =
(2)
\* more efficient
\* single master clock
67
1-43 digital hierarchy
Basic ISDN =
Residential
68
1-43 digital hierarchy
Primary ISDN North America =
(4)
\* large business
\* 1.544 Mb/s
\* 23 B channels
\* 1 D channel
69
1-43 digital hierarchy
Primary ISDN Europe =
(4)
\* large business
\*2.048 Mb/s
\* 30 B channels
\* 1 D channel
70
1-44 HSDL
HSDL =
(2)
## Footnote
\* high bit-rate digital subsciber line
\* DS1 over balananced twisted pair
71
1-44 SDSL
SDSL =
(2)
## Footnote
\* Symmetircal digital subscriber line
\* single pair version of HDSL - DS1 over 1pr balanced twisted pair cable
72
1-49 video transmission
Baseband signaling =
(2)
Composite and component
73
1-50 video transmission
Component format RGB =
Red, green, blue
74
1-51 broadband video
RF carrier=
Represents a TV channel
75
1-51 Balanced twisted pair media implementation
tradititional video transmission =
coax and fiber
76
1-51 Balanced twisted pair media implementation
Broaband analog CATV =
Category 5e or higher
77
1-53 transmission line concepts
Conductance (G) =
Represents leakage
78
1-53 Figure 1.16
resistive model
79
1-55 Figure 1.18
Inductive Model
80
1-59 transmission line concepts
Crosstalk =
Signal interference
81
1-59 transmission line concept
NVP =
(2)
\* percentage of the speed of light
\* .62c
82
1-59 transmission line concept
Balance twisted-pair cables =
.56c to .74c
83
1-60 transmission line concept
Delay skew =
(2)
\* difference in propagation delay
\* not to exceed 45ns
84
1-61 signal-to-noise ratio (SNR)
Q= 10mW signal input lead and 10 microwatts of noise 1 dB of loss per 100ft in a 1000ft run. What is rage SNR?
**20dB**
SNR (dB) = 20 log
( Vo / Vn) = 20 log (Vi / Vo)
Vo = received signal voltage level
Vn = noise signal voltage level at the receiver
Vi = transmitted signal voltage level
85
1-61 transmission line concepts
ACR =
(2)
\* Attenuation to Crosstalk ratio
\* minimum NEXT loss - maximum attenuation
86
1-62 Return loss
better impedance matching =
lower reflected engery and higher return loss
87
1-62 Return loss
Return loss =
derived from reflection coefficient
88
1-62 Return loss
mismatched impedance =
signal reflectoins (echoes)
89
1-63 balance twisted-pair performance
Balance twisted pair cables =
Impedance of 100 ohms
90
1-72 balance twisted-pair applications
ANSI/TIA/EIA-232-F =
^
ANSI/TIA/EIA-422-F =
^
\* 150ft
\* 50ft to 4000ft
91
1-72 balance twisted-pair applications
DS1 rate =
2 twisted-pair
92
1-72 balance twisted-pair applications
100BASE – T4 =
4 twisted-pair
93
1-72 balanced twisted-pair applications
10GBASE-T =
4 twisted-pair
94
1-75 Shared Sheath Applications and Compatibilty
No more than 12 10BASE-T =
in the same binder group
95
1-76 balanced twisted pair applications
Baluns =
(3)
\* impedance matching device
\* twisted-pair to coaxial and coaxial to twisted-pair
\* UTP to coaxial
96
1-77 Signal Converters
Advantages =
(2)
## Footnote
\* decrease EMI problems
\* extend DTE signal reach
97
1-79 optical fiber intro
Simple model of telecom systems =
(3)
\* transmitter
\* receiver
\* medium
98
1-80 optical fiber transmitters
850 nm/1300 nm =
1310 nm/1550 nm =
\* Multimode (mm)
\* singlemode (SM)
99
1-86 optical fiber transmitters
VCSEL =
Vertical cavity surface emitting laser
100
1-86 optical fiber transmitters
VSCEL advantages =
(2)
\* cost-effective mm transmitter for gigabit ethernet and fibre channel
\* 10Gigabit and fibre channel
101
1-90 optical fiber medium
Core size selection =
(3)
\* active equipment
\* distance
\* bandwidth (data rate)
102
1-91 optical fiber medium
Type Bandwidth
OM1 =
OM2 =
OM3 =
\* 62.5um MM 200 & 500MHz/km
\* 50um MM 500 & 500MHz/km
\* 50um laser, VSCEL 2000 &500MHz/km
103
1-91 Optical fiber media
OS2 =
Low-water peak
104
1-92 balance twisted-pair channel performance
ISO Class C =
ISO Class D =
\* Cat3, 16MHz
\* Cat5e, 100MHz
105
1-98 optical fiber bandwidth
Dispersion =
(3)
\* bandwidth limitations
\* light pulse to broaden
\* measured in picoseconds (psec)
106
1-99 optical fiber bandwidth
Chromatic dispersion =
Multimode
107
1-102 Optical fiber bandwidth
Classifications of fiber =
MM & SM
108
1-102 optical fiber bandwidth
MM 1Gb/s =
1804ft
109
1-106 optical fiber bandwidth
Visible light wavelengths =
400nm to 700nm
110
1-106 optical fiber bandwidth
wavelength =
Windows
111
1-107 optical fiber bandwidth
SM loss value =
(2)
\* outside cable .5dB
\* inside cable 1.0dB
112
1-109 optical fiber application support
12 connectors x 0.75dB =
6 connectors x 0.75dB =
\* 9.3
\* 4.8
113
1-109 optical fiber application support info
Maximum attenuation for
50um mm =
62.5um mm =
Singlemode (OSP) =
\* 3.5dB & 1.5dB
\* 3.5dB & 1.5dB
\* 0.5dB & 0.5dB
114
1-116 attenuation
Power penalty for:
LED's =
Lasers =
\* 2dB
\* 3dB
115
1-116 attenuation
Power penalty for repair margin =
Two repair splices
116
1-118 attenuation
Temperature changes =
2dB/km
117
1-118 attenuation
Maximum connection loss =
Maximum splice loss =
\* 0.75dB
\* 0.3dB
118
1-118 vattenuation
Splice loss for fusion:
MM & SM =
Max 0.3dB
119
1-118 attenuation
Splice loss of mechanical:
MM & SM =
Max 0.3dB
120
1-118 attenuation
Fusion =
Mechanical =
\*permanent, 0.3db
\* emergency/temporary, 0.3db
121
1-122 optical fiber SONET & SDH concepts
SONET =
Synchronous optical network
122
1-122 optical fiber SONET & SDH concepts
SDH =
Synchronous digital hierarchy
123
1-122 optical fiber SONET & SDH concepts
STS-1/OC-1 =
\* 51.84 MB/s
\* 672 voice channel
124
1-122 optical fiber SONET & SDH concepts
STS-3/OC-3 =
\* 155.52 MB/s
\* 2016 voice channels
125
1-122 optical fiber SONET & SDH concepts
STS-12/OC-12 =
622.08 Mb/s
8064 voice channels
126
1-123 Figure 1.30
mux =
DSX =
\* multiplexing
\* digital signal cross-connect
127
1-124 optical fiber SONET & SDH concepts
WDM =
(2)
\* wavelength division multiplexing
\* uses lenses
128
1-124 optical fiber SONET & SDH concepts
WDM lenses =
Refract and direct light
129
1-129 North American digital signal
DS1 =
DS1C =
DS3 =
\* 24 channels
\* 48 channels
\* 672 channels
