MAINTENANCE TECH I-II CONVENTIONAL QUESTIONS
AND CORRECT DETAILED ANSWERS (VERIFIED ANSWERS)
ALREADY GRADED A+
What advantage is realized by increasing the voltage in a broadband
cable network from 60 volts alternating current (VAC) to 90 volts?
Ans✓✓✓Operating with 50% more voltage reduces the voltage drop
and current drawn in the network for more efficient power utilization.
How does surge protection at the input and output of a ferroresonant
power supply defend against voltage surges? Ans✓✓✓By passing
voltage surges (within the surge device rating) to ground without
damage.
Which part of a ferroresonant transformer regulates the load on the
secondary winding? Ans✓✓✓The magnetic shunt.
In a standby network power supply, what comes online to convert the
battery voltage to alternating current (AC), which then goes to the
ferroresonant transformer? Ans✓✓✓The battery-powered inverter.
In a power inserter with three filtering networks, what is the purpose of
the high-pass filter? Ans✓✓✓To prevent the 60 hertz (Hz) alternating
current (AC) from passing between the two radio frequency (RF)/AC
ports.
,What inserts alternating current (AC) into the network with a direct
connection to an amplifier rather than using a power inserter?
Ans✓✓✓The amplifier AC circuitry.
What is the advantage for supplying alternating current (AC) to multiple
amplifiers from one network power supply? Ans✓✓✓Allows the
designer to place amplifiers without concern about access to electrical
utility power.
Where is a clamp-on ammeter attached to measure the output current
from a network power supply? Ans✓✓✓Clamped around the conductor
attached to the lug that tightens down on the coaxial cable connector pin.
What is a priority in any standby power supply maintenance program?
Ans✓✓✓Battery care.
What is the voltage into the second amplifier in cascade, if each
amplifier draws 1.5 amps of current, the loop resistance of each section
of cable is 1.38 ohms, and the alternating current (AC) source is a 90
volts AC (VAC) network power supply? Ans✓✓✓83.77 VAC.
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? Ans✓✓✓STB
and DOCSIS modems are assigned different upstream channels with
dedicated receivers in the headend.
, What did the 1.1 version of the Data Over Cable Service Interface
Specification (DOCSIS) introduce, incorporating solutions for
transporting real-time data applications (such as voice traffic) over the
cable operator's managed IP network, and doing so with quality
comparable to that of the telephone company? Ans✓✓✓PacketCable.
Why is 38 MHz typically the highest frequency in the sub-band
frequency that is used for upstream modem transmissions? Ans✓✓✓The
upper edge of the sub-band frequency spectrum is prone to group delay
caused by the diplex filters.
What enables the set-top box (STB) upstream carrier to be located below
20 MHz and still be reliably received? Ans✓✓✓The narrow bandwidth
and quadrature phase shift keying (QPSK) modulation.
What system is a byproduct of the "funneling effect"? Ans✓✓✓A many-
to-one system.
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.
Why does the output level from customer premises equipment (CPE)
vary? Ans✓✓✓To compensate for variable amounts of attenuation in
the return path of each device.
AND CORRECT DETAILED ANSWERS (VERIFIED ANSWERS)
ALREADY GRADED A+
What advantage is realized by increasing the voltage in a broadband
cable network from 60 volts alternating current (VAC) to 90 volts?
Ans✓✓✓Operating with 50% more voltage reduces the voltage drop
and current drawn in the network for more efficient power utilization.
How does surge protection at the input and output of a ferroresonant
power supply defend against voltage surges? Ans✓✓✓By passing
voltage surges (within the surge device rating) to ground without
damage.
Which part of a ferroresonant transformer regulates the load on the
secondary winding? Ans✓✓✓The magnetic shunt.
In a standby network power supply, what comes online to convert the
battery voltage to alternating current (AC), which then goes to the
ferroresonant transformer? Ans✓✓✓The battery-powered inverter.
In a power inserter with three filtering networks, what is the purpose of
the high-pass filter? Ans✓✓✓To prevent the 60 hertz (Hz) alternating
current (AC) from passing between the two radio frequency (RF)/AC
ports.
,What inserts alternating current (AC) into the network with a direct
connection to an amplifier rather than using a power inserter?
Ans✓✓✓The amplifier AC circuitry.
What is the advantage for supplying alternating current (AC) to multiple
amplifiers from one network power supply? Ans✓✓✓Allows the
designer to place amplifiers without concern about access to electrical
utility power.
Where is a clamp-on ammeter attached to measure the output current
from a network power supply? Ans✓✓✓Clamped around the conductor
attached to the lug that tightens down on the coaxial cable connector pin.
What is a priority in any standby power supply maintenance program?
Ans✓✓✓Battery care.
What is the voltage into the second amplifier in cascade, if each
amplifier draws 1.5 amps of current, the loop resistance of each section
of cable is 1.38 ohms, and the alternating current (AC) source is a 90
volts AC (VAC) network power supply? Ans✓✓✓83.77 VAC.
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? Ans✓✓✓STB
and DOCSIS modems are assigned different upstream channels with
dedicated receivers in the headend.
, What did the 1.1 version of the Data Over Cable Service Interface
Specification (DOCSIS) introduce, incorporating solutions for
transporting real-time data applications (such as voice traffic) over the
cable operator's managed IP network, and doing so with quality
comparable to that of the telephone company? Ans✓✓✓PacketCable.
Why is 38 MHz typically the highest frequency in the sub-band
frequency that is used for upstream modem transmissions? Ans✓✓✓The
upper edge of the sub-band frequency spectrum is prone to group delay
caused by the diplex filters.
What enables the set-top box (STB) upstream carrier to be located below
20 MHz and still be reliably received? Ans✓✓✓The narrow bandwidth
and quadrature phase shift keying (QPSK) modulation.
What system is a byproduct of the "funneling effect"? Ans✓✓✓A many-
to-one system.
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.
Why does the output level from customer premises equipment (CPE)
vary? Ans✓✓✓To compensate for variable amounts of attenuation in
the return path of each device.
