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NCT4 Flashcards

(73 cards)

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1
Q

Random electron activity in the atoms that make up the conductor

A

Thermal Noise

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2
Q

Noise floor in a 4MHz bandwidth @ 68*F is called:

A

Termination Noise

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3
Q

Difference in a peak carrier level to the noise floor:

A

Carrier to Noise

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4
Q

Amount of noise in a 4MHz bandwidth on a 75 Ohm cable @ 68*F

A

-59.16dB

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5
Q

FCC Spec for C/N

A

43dB

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6
Q

Undesired change in the waveform of a signal

A

distorion

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7
Q

Crossing of Modulation from one channel to another

A

XMOD or Cross Modulation

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8
Q

XMOD appears as

A

Vertical bars in the picture

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9
Q

2nd harmonics of any 2 channels are typically _____ below the sum/difference products

A

6dB

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10
Q

CTB products fall within _____ of the video carrier

A

30 KHz

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11
Q

Tilting the output of an amplifier improves:

A

Distortion performance

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12
Q

CSO beats fall @ __________ above the video carrier

A

1.25MHz +/- 15 KHz

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13
Q

unwanted sum/difference frequencies resulting from heterodyning of 2 or more signals

A

Beats

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14
Q

A horizontal bar in the picture is _______ Modulation

A

Hum

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15
Q

Primary cause of Hum (60Hz)

A

Power Passing Choke (60Hz)

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16
Q

A source of hum in older systems (120Hz)

A

Series regulated DC Power supplies (120Hz)

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17
Q

3 parts of fiber

A

Coating, Cladding, Core

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18
Q

When light stays in the core, this is called

A

Total Internal Reflection

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19
Q

2 wavelengths used in HFC Networks

A

1550nm & 1310nm

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20
Q

Most common type of fiber used in the cable industry

A

Single Mode Fiber

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21
Q

Wavelength is ________ proportional to frequency

A

Inversely

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22
Q

A shorter wavelength means a _______ Frequency

A

Higher

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23
Q

Compares the speed of light in a material to the speed of light in a vacuum

A

Index of Refraction

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24
Q

One Billionth of a meter

A

nanometer

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25
Device that takes the RF and modulates it onto an optical wavelength
Optical Transmitter
26
Optical transmitters use this type of diode
Laser Diode
27
What device detects light and demodulates it to RF
Optical Receiver
28
An optical receiver uses this type of Diode
Photo Diode
29
C/N Formula
L1-(NF-59.2)
30
Formula for C/N @ end of cascade
C/N1-10logN (C/N1 is equal to the C/N of a single amplifier in the cascade, N=Number of amplifiers)
31
XMOD Formula
XMOD1 - 20logN
32
CTB Formula
CTB1 - 20logN
33
Devices that are used to compensate for the forward and return loss
Amplifiers
34
What device compensates for the uneven cable loss in coax?
Equalizer
35
Amplifier input EQs are selected to do what?
Provide flat inputs to the first stage of amplification
36
amplifier interstage EQs are selected to do what?
Provide output tilt
37
Forwards trunk amplifiers are selected for their what?
Low Noise Figure (NF)
38
What compensates for fluctuations in the input signal?
AGC
39
The name of the frequency that is monitored by the AGC
Pilot
40
It provides a means to monitor levels with out interrupting service
Test Point
41
This device has substantial isolation between it's output & tap port:
Directional Coupler (DC)
42
What device has both a DC & Splitter built into it?
Tap
43
What device is considered to be the customer interface point?
Tap
44
This device compensates for reverse tilt on the feeder
In-Line EQ
45
This device has a diplex filter & a pad that will only affect the return
In-Line Conditioner
46
This device uses a low pass filter to prevent RF from entering the Power Supply
Line Power Inserter (LPI
47
This map only shows the poles & Strand
Strand Map
48
This map is the point where actives are added to the network
Design Map
49
This map shows the network changes from the original design as the design needed to be modified when it was being built
As-Built
50
This map shows only one Node
HFC Plant Map
51
The numbering system used to catalog plant maps is called:
Map Grid System
52
CLI
Cumulative Leakage Index
53
Leaks _____ and greater are included in the CLI calculation
50uV/m
54
CLI is performed how often?
annually
55
What form is used to submit CLI to the FCC?
320
56
Leakage monitoring must be performed how often?
Every 90 days
57
During Leakage monitoring, leaks _____ and greater must be logged and repaired
20uV/m
58
Leakage logs must be kept on file for how many years?
2
59
Signal levels that are ________ or higher must be offset
38.75dBmV
60
A method used to pin point a leak
Triangulation
61
FCC requires that measurements are made with a ______ antenna
Dipole (1/2 Wave Pole)
62
CTB falls within ______ of the video carrier
30KHz (all channels EXCEPT 5 & 6)
63
AM
Amplitude Modulation
64
PM
Phase Modulation
65
FM
Frequency Modulation
66
Modulation used for Video
Amplitude Modulation
67
Modulation used for Color
Phase Modulation
68
Modulation used for Audio
Frequency Modulation
69
The video carrier is ______ higher than the lower edge of the channel
1.25 MHz
70
The color carrier is ________ from the video carrier
3.58 MHz (4.83MHz from lower edge of channel)
71
The audio carrier is _________ from the video carrier
4.5 MHz
72
CSO fall ________ above the video carrier
1.25MHz +/- 15KHz
73
CTB are within _______ of the video carrier
30KHz

NCT4 (4 decks)

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