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NCTI MAINTENANCE I-II QUESTIONS WITH VERIFIED ANSWERS ALREADY GRADED A+
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NCTI MAINTENANCE I-II QUESTIONS WITH VERIFIED ANSWERS ALREADY GRADED A+
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Name: Score:130 Multiple choice questions
Term 1 of 130
Why does the output level from customer premises equipment (CPE) vary?
So that the amplifier gain is equal to the path attenuation that follows the amplifier.
Less sensitive than a leakage detector and doesn't have an alarm
-There is a lot of older fiber-cable still in use that may have unacceptable water-peak
attenuation.
-To compensate for variable amounts of attenuation in the return path of each device.
Term 2 of 130
How many decimal values can eight bits of data represent?
128
512
266
256
Term 3 of 130
What system is a byproduct of the "funneling effect"?
The location of the leak.
One-quarter wavelength.
Packetcable.
A many-to-one system.
,Term 4 of 130
When a laser light source is used to test fibers,
-By an elevated noise floor above 42 MHz after the optical signal has been converted
back to RF, typically in the headend.
The light source and optical power meter must be referenced together prior to making
any field measurement.
With the flux in the core saturated, then the secondary voltage remains constant as the
primary voltage changes.
A 2 kHz modulation provides a test signal that allows the fiber under test to be detected
by an optical fiber identifier.
Term 5 of 130
The forward path signal in a traditional tree-and-branch architecture
-The meter's calibration must be traceable to the National Institute of Standards
Technology (NIST).
-Confirm that the hybrid fiber/coax (HFC) network is working properly.
Originates at the headend and is transmitted downstream through coaxial trunk cable
and trunk amplifiers
-By ensuring that the RF input is at or above the specified minimum input level to all
amplifiers.
Term 6 of 130
What happens to the data throughput when transitioning from quadrature phase shift keying
(QPSK) to 16-QAM (quadrature amplitude modulation) in a channel of the same bandwidth?
The current increases 10%.
-The Max Hold function.
Sweep test pulse amplitude.
-The data throughput doubles.
,Term 7 of 130
When aligning the optical return path, what are the ideal characteristics of the test signal
injected into the upstream optical transmitter?
-A noise signal of the same bandwidth to be used for upstream transport.
-Advanced time division multiple access (A-TDMA).
A loose seizure screw in the downstream path
-Confirm that the hybrid fiber/coax (HFC) network is working properly.
Term 8 of 130
Why is using dBmV, a voltage measurement, acceptable to express the power per Hz power
allocation across the channel bandwidth?
-Because a constant 75-ohm impedance is being used.
The constant power per hertz (power/Hz) measurement.
To select equalizers and set the output amplitude levels
-Because of the calculations required.
Term 9 of 130
What media access control (MAC) protocols are specified for digital set-top boxes (STB)?
Slope and response variations of the headend and optical transport.
-Proof of good engineering practices and that test procedures are documented.
-The signal must be turned off.
-ALOHA and time division multiple access (TDMA).
, Term 10 of 130
What are the disadvantages of using an SLM for leakage detection?
-At the output of a forward amplifier because the forward levels are highest and the
return levels are lowest.
Less sensitive than a leakage detector and doesn't have an alarm
Leaks 20 µv/m or higher measured 10 feet from the cable.
There is no FCC specified time
Term 11 of 130
If your leakage detector indicates there is a leak and displays a reading of 14 microvolts per
meter (uV/m) when you are 80 feet from a possible leak source, what is the approximate
calculated level of the leak from 10 feet?
10 µv/m
224 μv/m.
107 μv/m.
112 μV/m.
Term 12 of 130
What enables set-top boxes (STB) and Data Over Cable Service Interface Specification
(DOCSIS) modems to operate as completely separate systems that operate independent of
each other?
The value of the attenuator pad at the input of the of the STB demodulator.
-STB and DOCSIS modems are assigned different upstream channels with dedicated
receivers in the headend.*
-If the noise floor drops less than 10 dB when the input signal is removed from the
spectrum analyzer.
-A stabilized light source, an optical return loss meter, an enhanced optical power meter,
and an optical talk set.
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