Ch. 1 * (Principles of Transmission) Flashcards
Alloying
Adverse effect
Most common electrical conductors…
Fiber does not belong
Advantages of stranded conductors
Except better transmission
Another name for insulation
Dielectric
North America standard
American Wire Gauge
Teflon
Dupont
Dielectric strength
Measures maximum voltage an insulation can withstand without breakdown
Reason for twisting pairs
Minimize Crosstalk
Mutual inductance
Magnetic field
Direction of twists
Counter clockwise
Where are high temperatures found?
Exterior building walls, ceiling spaces, mechanical rooms
Types of shields
Fiber does not belong
Braid
Good
Foil
Excellent
Shield effectiveness
Less than 20 dB = poor
More than 60 dB = excellent
Braid/Magnetic Field rating
Poor
Drain wires
Applied longitudinally
Analog signal
Sign wave
Range of human hearing
20-20,000 Hz
Frequency of telephone circuits
300-3,400 Hz
Wave
Sinusoidal
Sinusoidal theory
Joseph Fourier
Phase
Time
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?
30
Telecommunications transmission system consists of three basic components:
Source
Medium
Receiver
Speed of light
186,000
Speed of cable
.56c - .74c
Round-trip delay for satellites
.25
Power source options for VoIP
Except “bridge”
Digital signals
Discrete steps
One cycle
360 degrees
Sampling theory
Harry Nyquist
Companding types
Mu-Law
A-Law
Companding standard for U.S.
Mu-Law
PCM
Pulse Code Modulation
PCM
256
OC1
ATM (STS-1)
Encoding rate of STS–1
51.8 Mbps
OC-3
ATM (STS-3)
Encoding rate of STS–3
155 Mbps
Transmission circuit classifications
Simplex
Half duplex
Full duplex
Except…
Baseband analog signal types
Composite
Component
Component format
RGB
Resistive model
Teeth
Inductive model
Rings
10 milliwatt signal on input lead and 10 microwatt of noise in a 1,000’ run:
SNR = 20dB
10BASE-T
10BASE-T4
4 Pairs
Three parts comprising a simple telecommunications system:
Transmitter
Receiver
Medium
Multimode wavelength
850
1300
Single mode wavelength
1310
1550
VCSEL
Vertical cavity surface emitting laser
Factors for determining fiber type
Distance
Bandwidth
Active equipment
OM1
62.5/125
OM2
50/125
OM3
50/125 (laser)
OS1
Singlemode
OS2
Singlemode (low water-peak)
Frequency of category 3
16 MHz
Frequency of category 5e
100 MHz
Fiber dispersion
Picoseconds
Classifications of fiber
Multimode
Singlemode