NCTI MT1-MT2
A dipole antenna is used for FCC tests because: - ANS-Its performance is well characterized.
A light source - ANS-Is crucial for accurately measuring optical fiber power and attenuation.
A wavelength-isolating power meter is most commonly used in - ANS-Point-to-multipoint FTTX
installations.
According to SCTE- and NCTA- recommended trunk system map symbols, fiber-optic cable is
represented by - ANS-Double arrows within a small circle on a solid line.
According to the FCC, the leakage log should contain which of the following? - ANS-The
probable cause of the leakage.
Across 6 MHz, what is the maximum in- channel frequency response (ICFR) defined in the Data
Over Cable Service Interface Specification (DOCSIS)? - ANS-3.0 dB peak-to-valley (P/N).
Besides RS-232 ports, what type of interface is common on an optical power meter? - ANS-A
USB interface can provide easy download of information to a PC.
Centralized power configurations - ANS-provide the advantage of increased reliability through
sharing of expensive backup generators and sophisticated monitoring equipment among
different power realms.
Chipsets with ingress cancellation algorithms are most effective for removing impairments in
what portion of the RF return frequency spectrum? - ANS-Within the upstream channel
bandwidth
CLI calculations do not include leakage below: - ANS-50 uv/m.
decimal values can eight bits How many of data represent? - ANS-256
During aerial plant construction, - ANS-The strand is tensioned so its sag profile matches that of
the overhead utility power lines.
Even though the downstream sweep test pulses are intended to fit in the narrow frequency band
between channels, what parameter can cause interference if set too high? - ANS-Sweep test
pulse amplitude.
House amplifiers with a passive return path are used for what type of situation? - ANS-For
situations when long service drops are used and the forward path needs to be amplified but
return path amplification is unnecessary.
How can the amount of thermal noise added to a network be minimized? - ANS-By ensuring
that the RF input is at or above the specified minimum input level to all amplifiers..
How does the signal attenuation through coaxial cable in the sub-band frequency spectrum
compare to the attenuation at forward path frequencies? - ANS-At sub-band frequencies, the
signal attenuation is significantly less than in the forward path.
How is impulse noise characterized when viewed on a spectrum analyzer? - ANS-Impulse noise
will appear as random spikes of energy across the entire return path frequency spectrum (5 to
42 MHz).
How is laser clipping in the return path characterized on a spectrum analyzer? - ANS-By an
elevated noise floor above 42 MHz after the optical signal has been converted back to RF
typically in the headend.
, How long must the leakage log be kept on file? - ANS-2 Years.
How must a directional test point be installed in an amplifier to enable insertion of upstream
sweep pulses and view the downstream sweep? - ANS-In a path common to the downstream
and upstream.
If a large signal leak is found in the aerial plant, what is a good first step in locating the leak? -
ANS-Drive around until an absolute peak is found.
If a return path impairment appears to be caused by impulse noise, why is it a good idea to
begin troubleshooting at distribution taps of 17 dB or lower? - ANS-Low value taps have less
isolation between ports and offer less attenuation to ingress and impulse noise coming from an
individual drop system.
If the power out of a transformer must equal the power in, assuming zero efficiency loss, what
happens to the output current when the transformed output voltage is 10% lower? - ANS-The
current increases 10%.
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? - ANS-112 uV/m.
In a basic step-up switcher circuit design, what does the inductor do when the switch is closed
and conducting current to ground? - ANS-It stores energy in its magnetic field with the current
lagging the voltage by 90 degrees.
In a basic step-up switcher circuit design, what is the relationship of the square- wave duty cycle
to the output voltage? - ANS-The larger the duty cycle, the higher the voltage.
In a DOCSIS 3.1 orthogonal frequency division multiple access (OFDMA) upstream channel, the
average power of the subcarriers are normalized to what bandwidth? - ANS-1.6 MHz.
In a feedback linear regulator, what enables a stable output voltage while enabling a wide range
of output current through the load? - ANS-The current across the Zener diode is constant.
In a HFC network, - ANS-Processing equipment in the headend converts the forward RF signal
to a light signal.
In a series-pass transistor regulator, which component isolates the Zener diode from changes in
the load for improved voltage regulation. - ANS-The emitter follower configured transistor
(series-pass transistor).
In a traditional analog return, the optical detectors are responsive to the power of the received
signal. How does the signal level at the output of the upstream receiver relate to changes to its
input power? - ANS-The signal level at the output of the upstream receiver changes 2 dB for
every 1 dB change of received optical power level.
In modern sweep systems, what type of nonintrusive and noninterfering test signal is inserted
into the downstream? - ANS-Narrow band continuous wave (CW) test carriers, called pulses a
frequencies between channels.
In the traditional analog return path, what is critical about the upstream optical transmitter? -
ANS-To make sure the RF level into the upstream transmitter is correct.
In what applications are avalanche photodiodes (APD) most likely to be used? - ANS-In
fiber-to-the-home (FTTH) architectures where the high attenuation of optical splitters must be
overcome.
A dipole antenna is used for FCC tests because: - ANS-Its performance is well characterized.
A light source - ANS-Is crucial for accurately measuring optical fiber power and attenuation.
A wavelength-isolating power meter is most commonly used in - ANS-Point-to-multipoint FTTX
installations.
According to SCTE- and NCTA- recommended trunk system map symbols, fiber-optic cable is
represented by - ANS-Double arrows within a small circle on a solid line.
According to the FCC, the leakage log should contain which of the following? - ANS-The
probable cause of the leakage.
Across 6 MHz, what is the maximum in- channel frequency response (ICFR) defined in the Data
Over Cable Service Interface Specification (DOCSIS)? - ANS-3.0 dB peak-to-valley (P/N).
Besides RS-232 ports, what type of interface is common on an optical power meter? - ANS-A
USB interface can provide easy download of information to a PC.
Centralized power configurations - ANS-provide the advantage of increased reliability through
sharing of expensive backup generators and sophisticated monitoring equipment among
different power realms.
Chipsets with ingress cancellation algorithms are most effective for removing impairments in
what portion of the RF return frequency spectrum? - ANS-Within the upstream channel
bandwidth
CLI calculations do not include leakage below: - ANS-50 uv/m.
decimal values can eight bits How many of data represent? - ANS-256
During aerial plant construction, - ANS-The strand is tensioned so its sag profile matches that of
the overhead utility power lines.
Even though the downstream sweep test pulses are intended to fit in the narrow frequency band
between channels, what parameter can cause interference if set too high? - ANS-Sweep test
pulse amplitude.
House amplifiers with a passive return path are used for what type of situation? - ANS-For
situations when long service drops are used and the forward path needs to be amplified but
return path amplification is unnecessary.
How can the amount of thermal noise added to a network be minimized? - ANS-By ensuring
that the RF input is at or above the specified minimum input level to all amplifiers..
How does the signal attenuation through coaxial cable in the sub-band frequency spectrum
compare to the attenuation at forward path frequencies? - ANS-At sub-band frequencies, the
signal attenuation is significantly less than in the forward path.
How is impulse noise characterized when viewed on a spectrum analyzer? - ANS-Impulse noise
will appear as random spikes of energy across the entire return path frequency spectrum (5 to
42 MHz).
How is laser clipping in the return path characterized on a spectrum analyzer? - ANS-By an
elevated noise floor above 42 MHz after the optical signal has been converted back to RF
typically in the headend.
, How long must the leakage log be kept on file? - ANS-2 Years.
How must a directional test point be installed in an amplifier to enable insertion of upstream
sweep pulses and view the downstream sweep? - ANS-In a path common to the downstream
and upstream.
If a large signal leak is found in the aerial plant, what is a good first step in locating the leak? -
ANS-Drive around until an absolute peak is found.
If a return path impairment appears to be caused by impulse noise, why is it a good idea to
begin troubleshooting at distribution taps of 17 dB or lower? - ANS-Low value taps have less
isolation between ports and offer less attenuation to ingress and impulse noise coming from an
individual drop system.
If the power out of a transformer must equal the power in, assuming zero efficiency loss, what
happens to the output current when the transformed output voltage is 10% lower? - ANS-The
current increases 10%.
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? - ANS-112 uV/m.
In a basic step-up switcher circuit design, what does the inductor do when the switch is closed
and conducting current to ground? - ANS-It stores energy in its magnetic field with the current
lagging the voltage by 90 degrees.
In a basic step-up switcher circuit design, what is the relationship of the square- wave duty cycle
to the output voltage? - ANS-The larger the duty cycle, the higher the voltage.
In a DOCSIS 3.1 orthogonal frequency division multiple access (OFDMA) upstream channel, the
average power of the subcarriers are normalized to what bandwidth? - ANS-1.6 MHz.
In a feedback linear regulator, what enables a stable output voltage while enabling a wide range
of output current through the load? - ANS-The current across the Zener diode is constant.
In a HFC network, - ANS-Processing equipment in the headend converts the forward RF signal
to a light signal.
In a series-pass transistor regulator, which component isolates the Zener diode from changes in
the load for improved voltage regulation. - ANS-The emitter follower configured transistor
(series-pass transistor).
In a traditional analog return, the optical detectors are responsive to the power of the received
signal. How does the signal level at the output of the upstream receiver relate to changes to its
input power? - ANS-The signal level at the output of the upstream receiver changes 2 dB for
every 1 dB change of received optical power level.
In modern sweep systems, what type of nonintrusive and noninterfering test signal is inserted
into the downstream? - ANS-Narrow band continuous wave (CW) test carriers, called pulses a
frequencies between channels.
In the traditional analog return path, what is critical about the upstream optical transmitter? -
ANS-To make sure the RF level into the upstream transmitter is correct.
In what applications are avalanche photodiodes (APD) most likely to be used? - ANS-In
fiber-to-the-home (FTTH) architectures where the high attenuation of optical splitters must be
overcome.
