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