ROC 2 PART 2 Questions and Answers
Cumulative Leakage Index (CLI) - ✔ A calculation of the relative amount of signal
leakage in a broadband cable network that is provided annually as a numerical score to
the Federal Communications Commission (FCC) that represents a cable system's
signal leakage prevention.
Triangulation - ✔ A signal leakage-finding technique in which the intersection of an
imaginary line drawn at a right angel from two separate dipole antenna locations
identifies the leakage source.
Near-field probe - ✔ A short antenna fixed at the end of a connector cable that allows
for close-in measurements in places such as attics or crawl spaces; signal leakage
antenna that provides the most narrowly focused measurement and the greatest
accuracy, often used in confined areas such as attics or crawl spaces.
Which of the following problem(s) are caused by egress from a hybrid fiber/coax (HFC)
network? - ✔ • Interference with aeronautical navigation and communication, amateur
radio, public service, and cellular communications.
What leakage level must be entered in the leakage log? - ✔ • Leaks 20 microvolts per
meter (μV/m) or higher measured 10 feet from the cable.
Which is a benefit of an aggressive signal leakage policy?• - ✔ Decreased ingress-
related service calls.
What is done for leak measuring 1.25 microvolts per meter (μV/m) from about 160 feet
away from the coaxial cable network?• - ✔ The leak level is likely 20 μV/m or higher
when measured 10 feet from the cable and must be fixed and recorded in the leakage
log.
If the leakage detector indicates there is a leak and displays a reading of 14 microvolts
per meter (uV/m) measured at 80 feet from a possible leak source, what is the
approximate calculated level of the leak from 10 feet? - ✔ • 112 uV/m.
When using the triangulation technique to find the source of a leak, why is a dipole
antenna used? - ✔ • The dipole antenna is directional and picks up the strongest signal
that is at a right angle, or perpendicular to the antenna elements.
When trying to find the source of a very strong leakage signal, what should be done? -
✔ • Reduce the sensitivity of the leakage detector or even remove the antenna and
allow the connector alone to pick up the leakage signal.
When troubleshooting signal leakage in the drop system, what does it mean if all signs
of signal leakage disappear when the ground block is disconnected and terminated on
,the side connected to the customer premises? - ✔ • Something in the customer
premises is the leakage source.
According to the Federal Communications Commission (FCC) leakage regulations,
what distance must an antenna be from the network for leakage level measurements? -
✔ • The antenna must be 3 meters (10 feet) from the network elements and 3 meters
(10 feet) above the ground.
When calculating the network cumulative leakage index (CLI), what is done with leaks
that are equal to or greater than 50 microvolts per meter (µVm) measured 10 feet from
the network? - ✔ • The leakage values are squared and then added together, then
multiplied times a factor based on how much of the network was tested in 90 days.
What geometric shape is a sine wave based upon? - ✔ • A right-degree triangle.
What are the three elements of a carrier wave that can be manipulated? - ✔ •
Amplitude, frequency, and phase.
What are the peaks and minima of the amplitude modulation (AM) waveform envelope
related to? - ✔ • The amplitude of the modulation signal.
In a hybrid fiber/coax (HFC) network what type of crude amplitude modulation (AM)
detector causes common path distortion (CPD)? - ✔ • An envelope detector.
In a conventional amplitude modulation (AM) transmission, how much power is in the
sidebands and how much is in the carrier? - ✔ • Two-thirds of the power is in the carrier
with one-third in the sidebands.
Why can Carson's Rule be used to determine the bandwidth of a frequency modulation
(FM) carrier? - ✔ • In most cases, the amplitude of the sidebands furthest from the
carrier frequency are so low that they can be ignored.
Applying Carson's Rule to calculate the bandwidth of a narrowband frequency
modulation (FM) signal, which factor below must be known? - ✔ • The maximum
modulation signal frequency.
Under what principle do frequency modulation (FM) detector circuit designs operate? -
✔ • That voltage is created when the signal frequency moves from the center
frequency.
How many symbols are available at the output of a quadrature phase shift keying
(QPSK) modulator? - ✔ 4 symbols, each containing 2 bits of data.
Capacitor - ✔ Electronic component comprised of two parallel conductors separated by
dielectric material that when charged, temporarily stores energy in the form of an
, electrostatic field. Common applications are in power supplies to filter AC, and to block
DC or low frequency AC signals while passing high frequency RF signals.
What information remains after the intermediate frequency (IF) signal is detected, or
demodulated? - ✔ Analog or digital baseband information.
In a radio receiver, what is almost universally used to conduct the energy between the
antenna and the receiver tuner? - ✔ • Coaxial cable.
What two significant signals go into the mixer to create the intermediate frequency (IF)?
- ✔ The RF signal frequency at the output of the front-end filter and the local oscillator
(LO) signal.
What part of a receiver has several functions that include limiting the number of signals
that reach the amplifier and mixer? - ✔ The front-end filter.
What is used in set-top boxes (STB) to strike a balance between image rejection, the
bandwidth of the intermediate frequency (IF) filter, and the frequency at which
demodulation is done? - ✔ • Double IF conversion.
What type of bandpass filters offer the precision, stability, and bandwidth most suitable
for TV and set-top box (STB) intermediate frequency (IF) sections? - ✔ • Surface
acoustic wave (SAW) filters.
What is used in some receivers to remove all attenuation before the amplifier until the
received signal level reaches a designed threshold? - ✔ • Delayed automatic gain
control (AGC).
Which class of amplifier utilizes a push-pull amplifier configuration in which each
transistor conducts current during opposite cycles of the input signal? - ✔ • Class B
amplifier.
Which class of amplifier has an output that is very high in harmonics and must be
attenuated by a filter network? - ✔ Class C amplifier.
Which class of amplifier efficiency approaches, but never achieves, 100%? - ✔ • Class
D amplifier.
Ferroresonant - ✔ A power supply technology that uses the non-linear inductance of a
transformer with a resonate capacitor to effectively operate with a steady output voltage
with changing input voltages.
What characterizes N-doped silicon that is used in bipolar junction transistors (BJT)? -
✔ • N-doped silicon has an excess of free electrons compared to P-doped silicon.
Cumulative Leakage Index (CLI) - ✔ A calculation of the relative amount of signal
leakage in a broadband cable network that is provided annually as a numerical score to
the Federal Communications Commission (FCC) that represents a cable system's
signal leakage prevention.
Triangulation - ✔ A signal leakage-finding technique in which the intersection of an
imaginary line drawn at a right angel from two separate dipole antenna locations
identifies the leakage source.
Near-field probe - ✔ A short antenna fixed at the end of a connector cable that allows
for close-in measurements in places such as attics or crawl spaces; signal leakage
antenna that provides the most narrowly focused measurement and the greatest
accuracy, often used in confined areas such as attics or crawl spaces.
Which of the following problem(s) are caused by egress from a hybrid fiber/coax (HFC)
network? - ✔ • Interference with aeronautical navigation and communication, amateur
radio, public service, and cellular communications.
What leakage level must be entered in the leakage log? - ✔ • Leaks 20 microvolts per
meter (μV/m) or higher measured 10 feet from the cable.
Which is a benefit of an aggressive signal leakage policy?• - ✔ Decreased ingress-
related service calls.
What is done for leak measuring 1.25 microvolts per meter (μV/m) from about 160 feet
away from the coaxial cable network?• - ✔ The leak level is likely 20 μV/m or higher
when measured 10 feet from the cable and must be fixed and recorded in the leakage
log.
If the leakage detector indicates there is a leak and displays a reading of 14 microvolts
per meter (uV/m) measured at 80 feet from a possible leak source, what is the
approximate calculated level of the leak from 10 feet? - ✔ • 112 uV/m.
When using the triangulation technique to find the source of a leak, why is a dipole
antenna used? - ✔ • The dipole antenna is directional and picks up the strongest signal
that is at a right angle, or perpendicular to the antenna elements.
When trying to find the source of a very strong leakage signal, what should be done? -
✔ • Reduce the sensitivity of the leakage detector or even remove the antenna and
allow the connector alone to pick up the leakage signal.
When troubleshooting signal leakage in the drop system, what does it mean if all signs
of signal leakage disappear when the ground block is disconnected and terminated on
,the side connected to the customer premises? - ✔ • Something in the customer
premises is the leakage source.
According to the Federal Communications Commission (FCC) leakage regulations,
what distance must an antenna be from the network for leakage level measurements? -
✔ • The antenna must be 3 meters (10 feet) from the network elements and 3 meters
(10 feet) above the ground.
When calculating the network cumulative leakage index (CLI), what is done with leaks
that are equal to or greater than 50 microvolts per meter (µVm) measured 10 feet from
the network? - ✔ • The leakage values are squared and then added together, then
multiplied times a factor based on how much of the network was tested in 90 days.
What geometric shape is a sine wave based upon? - ✔ • A right-degree triangle.
What are the three elements of a carrier wave that can be manipulated? - ✔ •
Amplitude, frequency, and phase.
What are the peaks and minima of the amplitude modulation (AM) waveform envelope
related to? - ✔ • The amplitude of the modulation signal.
In a hybrid fiber/coax (HFC) network what type of crude amplitude modulation (AM)
detector causes common path distortion (CPD)? - ✔ • An envelope detector.
In a conventional amplitude modulation (AM) transmission, how much power is in the
sidebands and how much is in the carrier? - ✔ • Two-thirds of the power is in the carrier
with one-third in the sidebands.
Why can Carson's Rule be used to determine the bandwidth of a frequency modulation
(FM) carrier? - ✔ • In most cases, the amplitude of the sidebands furthest from the
carrier frequency are so low that they can be ignored.
Applying Carson's Rule to calculate the bandwidth of a narrowband frequency
modulation (FM) signal, which factor below must be known? - ✔ • The maximum
modulation signal frequency.
Under what principle do frequency modulation (FM) detector circuit designs operate? -
✔ • That voltage is created when the signal frequency moves from the center
frequency.
How many symbols are available at the output of a quadrature phase shift keying
(QPSK) modulator? - ✔ 4 symbols, each containing 2 bits of data.
Capacitor - ✔ Electronic component comprised of two parallel conductors separated by
dielectric material that when charged, temporarily stores energy in the form of an
, electrostatic field. Common applications are in power supplies to filter AC, and to block
DC or low frequency AC signals while passing high frequency RF signals.
What information remains after the intermediate frequency (IF) signal is detected, or
demodulated? - ✔ Analog or digital baseband information.
In a radio receiver, what is almost universally used to conduct the energy between the
antenna and the receiver tuner? - ✔ • Coaxial cable.
What two significant signals go into the mixer to create the intermediate frequency (IF)?
- ✔ The RF signal frequency at the output of the front-end filter and the local oscillator
(LO) signal.
What part of a receiver has several functions that include limiting the number of signals
that reach the amplifier and mixer? - ✔ The front-end filter.
What is used in set-top boxes (STB) to strike a balance between image rejection, the
bandwidth of the intermediate frequency (IF) filter, and the frequency at which
demodulation is done? - ✔ • Double IF conversion.
What type of bandpass filters offer the precision, stability, and bandwidth most suitable
for TV and set-top box (STB) intermediate frequency (IF) sections? - ✔ • Surface
acoustic wave (SAW) filters.
What is used in some receivers to remove all attenuation before the amplifier until the
received signal level reaches a designed threshold? - ✔ • Delayed automatic gain
control (AGC).
Which class of amplifier utilizes a push-pull amplifier configuration in which each
transistor conducts current during opposite cycles of the input signal? - ✔ • Class B
amplifier.
Which class of amplifier has an output that is very high in harmonics and must be
attenuated by a filter network? - ✔ Class C amplifier.
Which class of amplifier efficiency approaches, but never achieves, 100%? - ✔ • Class
D amplifier.
Ferroresonant - ✔ A power supply technology that uses the non-linear inductance of a
transformer with a resonate capacitor to effectively operate with a steady output voltage
with changing input voltages.
What characterizes N-doped silicon that is used in bipolar junction transistors (BJT)? -
✔ • N-doped silicon has an excess of free electrons compared to P-doped silicon.
