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NCT4 > NCT4 > Flashcards

NCT4 Flashcards

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
Q

Device that takes the RF and modulates it onto an optical wavelength

A

Optical Transmitter

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26
Q

Optical transmitters use this type of diode

A

Laser Diode

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27
Q

What device detects light and demodulates it to RF

A

Optical Receiver

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28
Q

An optical receiver uses this type of Diode

A

Photo Diode

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29
Q

C/N Formula

A

L1-(NF-59.2)

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30
Q

Formula for C/N @ end of cascade

A

C/N1-10logN (C/N1 is equal to the C/N of a single amplifier in the cascade, N=Number of amplifiers)

31
Q

XMOD Formula

A

XMOD1 - 20logN

32
Q

CTB Formula

A

CTB1 - 20logN

33
Q

Devices that are used to compensate for the forward and return loss

A

Amplifiers

34
Q

What device compensates for the uneven cable loss in coax?

A

Equalizer

35
Q

Amplifier input EQs are selected to do what?

A

Provide flat inputs to the first stage of amplification

36
Q

amplifier interstage EQs are selected to do what?

A

Provide output tilt

37
Q

Forwards trunk amplifiers are selected for their what?

A

Low Noise Figure (NF)

38
Q

What compensates for fluctuations in the input signal?

A

AGC

39
Q

The name of the frequency that is monitored by the AGC

A

Pilot

40
Q

It provides a means to monitor levels with out interrupting service

A

Test Point

41
Q

This device has substantial isolation between it’s output & tap port:

A

Directional Coupler (DC)

42
Q

What device has both a DC & Splitter built into it?

A

Tap

43
Q

What device is considered to be the customer interface point?

A

Tap

44
Q

This device compensates for reverse tilt on the feeder

A

In-Line EQ

45
Q

This device has a diplex filter & a pad that will only affect the return

A

In-Line Conditioner

46
Q

This device uses a low pass filter to prevent RF from entering the Power Supply

A

Line Power Inserter (LPI

47
Q

This map only shows the poles & Strand

A

Strand Map

48
Q

This map is the point where actives are added to the network

A

Design Map

49
Q

This map shows the network changes from the original design as the design needed to be modified when it was being built

A

As-Built

50
Q

This map shows only one Node

A

HFC Plant Map

51
Q

The numbering system used to catalog plant maps is called:

A

Map Grid System

52
Q

CLI

A

Cumulative Leakage Index

53
Q

Leaks _____ and greater are included in the CLI calculation

A

50uV/m

54
Q

CLI is performed how often?

A

annually

55
Q

What form is used to submit CLI to the FCC?

A

320

56
Q

Leakage monitoring must be performed how often?

A

Every 90 days

57
Q

During Leakage monitoring, leaks _____ and greater must be logged and repaired

A

20uV/m

58
Q

Leakage logs must be kept on file for how many years?

A

2

59
Q

Signal levels that are ________ or higher must be offset

A

38.75dBmV

60
Q

A method used to pin point a leak

A

Triangulation

61
Q

FCC requires that measurements are made with a ______ antenna

A

Dipole (1/2 Wave Pole)

62
Q

CTB falls within ______ of the video carrier

A

30KHz (all channels EXCEPT 5 & 6)

63
Q

AM

A

Amplitude Modulation

64
Q

PM

A

Phase Modulation

65
Q

FM

A

Frequency Modulation

66
Q

Modulation used for Video

A

Amplitude Modulation

67
Q

Modulation used for Color

A

Phase Modulation

68
Q

Modulation used for Audio

A

Frequency Modulation

69
Q

The video carrier is ______ higher than the lower edge of the channel

A

1.25 MHz

70
Q

The color carrier is ________ from the video carrier

A

3.58 MHz (4.83MHz from lower edge of channel)

71
Q

The audio carrier is _________ from the video carrier

A

4.5 MHz

72
Q

CSO fall ________ above the video carrier

A

1.25MHz +/- 15KHz

73
Q

CTB are within _______ of the video carrier

A

30KHz

NCT4 (4 decks)

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