ROC I: Lesson Quizzes Only
1 mV decrease in a signal level of 40 dBmV is approximately equivalent to a decrease in level of
0.1 dB
minimum acceptable signal level of 0 dBmV at a TV set
1 mV across 75 ohms
you are planning a fiber optic network and want to amplify the signal so you can send it farther into the field. at which wavelength must the laser emit?
1,550 nm
input to output power ratio of a coax cable with 1 dB of attenuation
1.2589:1
power ratio for 2 dB
1.585:1
in a docsis 3.1 orthogonal frequency division multiple access (OFDMA) upstream channel, the average power of the subcarriers are normalized to what bandwidth?
1.6 MHz
input to output power ratio for 2 bels of similar impedance cable
100:1
which of the following are the aeronautical frequency bands?
108-137 and 225-400 MHz
one tenth bel or 1 dB is equal to
10th root of the bel ratio
How much signal is necessary from the subscriber's tap port @ 750 MHz to provide a minimum of 3.0 dBmV to the TV set when the drop is 150 feet of Series 6 cable and just one outlet (use 5.65 dB per 100 feet for the attenuation rate and round off to the nearest tenth of a dBmV)?
11.5 dBmV
the code words and spreading algorithm of synchronous code division multiple access (S-CDMA) enable simultaneous transmission of up to how many modems on the same RF return channel?
128
How much signal is needed from the subscriber's tap port @ 750 MHz to provide a minimum of +3.0 dBmV to each of the TV sets when there is 132 feet of Series 6 cable and a two-way splitter? (Use 5.65 dB per 100 feet for the Series 6 cable attenuation rate and 4.0 dB for the splitter attenuation)
14.5 dBmV
calculate the capacitive reactance of a power inserter's feed through capacitor when (1) the frequency is 60 Hz and (2) the capacitance value is 1,000 pF
2.65 M ohms
according to the FCC, leaks (blank) and above measured (blank) feet from the cable must be logged and repaired
20 uv/m, 10
1:5 ratio as a percentage
20%
signal increase of 1 dB represents a (blank) increase in power
25.89%
how many decimal values can eight bits of data represent?
265
the output port RF signal level is (blank) dBmV at 55.25 MHz and the tap port signal level is (blank) dBmV at 55.25 MHz for a two-way feed-through tap when: (1) the input port signal level is 30.5 dBmV at 55.25 MHz; (2) the insertion loss is 3.3 dB at 55.25 MHz; and (3) the tap loss is 7.6 dB at 55.25 MHz
27.2 and 22.9
What is the max tap value that can be installed when the tap is connected directly to a line extender amplifier output and: (1) the line extender output is 45 dBmV @ 745.25 MHz; (2) the longest amount of Series 6 coaxial cable from the tap to either of the two TV sets is 150 feet; (3) the Series 6 coaxial cable attenuation rate is 5.65 dB/100 feet @ 750 MHz; (4) the drop includes a splitter with a 4.0 dB loss; and (5) the system minimum signal level required at each of the two TV sets is 3.0 dBmV?
29 dB
When the output of a line extender is 3 dB lower than it normally should be
3 dB lower than normal from that point on
input to output power ratio of 10:1 has an input to output voltage ration of
3.162:1
when calculating return path attenuation in the drop system, what is the attenuation loss through the hot-leg of an unbalanced three-way splitter at sub-split frequencies?
3.5 dB
when using a digital signal analyzer to troubleshoot data throughput in the Data Over Cable Service Interface Specification (DOCSIS) network, what is the minimum modulation error ratio (MER) into the cable modem for a 256 quadrature amplitude modulation (QAM) carrier?
32 dB or greater
what is the output port signal level at 547.25 MHz for a directional coupler when: (1) the input signal level is 35.0 dBmV at 547.25 MHz; (2) the output port insertion loss value is 1.4 dB at 547.25 MHz and 0.7 dB at 55.25 MHz; (3) the tap port insertion loss value is 16.2 dB at 547.25 MHz and 15.9 dB at 55.25 MHz; and (4) the tap to output port isolation value is 18 dB at both 547.25 MHz and 55.25 MHz?
33.6 dBmV
what is the return signal pass band frequency used in most of North America?
5-42 MHz
what is the AC input voltage of a power inserter when: (1) the cable between the power supply and the power inserter is 200 feet long; (2) the power supply cable's DC loop resistance is 1.07 ohms/1,000 feet; (3) the power supply output voltage is 60 VAC; and (4) the total current requirements is 11.4 amps?
57.56 VAC
what would be the downstream throughput if two quadrature amplitude modulation (QAM) channels with a throughput of 38 Mbps were bonded?
76 Mbps
what is the tap port RF signal level at 547.25 MHz for a foyr-way terminating tap when: (1) the preceding tap's output port signal level is 25.0 dBmV at 547.25 MHz; (2) the cable length between the two taps is 110 feet; (3) the cable loss rate specification is 1.82 dB/100 feet at 550 MHz and 0.54 dB/100 feet at 50 MHz; and (4) the tap loss is 14.2 dB at 546.25 MHz?
8.8 dBmV
length of coax with attenuation of 10 dB will experience an input RF signal power loss of (blank), with (blank) of the signal remaining
90%, 10%
what media access control (MAC) protocols are specified for digital set-top boxes (STB)
ALOHA and time division multiple access (Tdma)
which Data Over Cable Service Interface Specification (DOCSIS) version was the first to provide an option for raising the top frequency of the upstream spectrum to 85 megahertz (MHz) in order to create enough bandwidth for upstream carriers from modems running on previous DOCSIS versions?
DOCSIS 3.0
Which DOCSIS over Cable Service Interface Specification (DOCSIS) layer is used by the cable modem termination system (CMTS) to differentiate between cable modems?
DOCSIS Data Link Layer (DDL)
Three networks of the PacketCable 1.0 architecture are
DOCSIS HFC (hybrid fiber/coax) access network; managed IP network: and PSTN
which of the following automatically captures the location of leakage data right down to the street address?
GPS assisted leakage measurement instruments
How does internet protocol (IP) multicast differ from IP broadcast?
IP multicast traffic is only sent to specific modem addresses on the network; IP broadcast is sent to all modems on the network
the first version of the Data Over Cable Service Interface Specification (DOCSIS) was approved as an international standard by what organization?
International Telecommunications Union (ITU)
which layers of the Open Systems Interconnection (OSI) reference model are specific to cable networks and are present only between Data Over Cable Service Interface Specification (DOCSIS) modems and the cable modem termination system (CMTS)?
Layers 1 through 4 (Physical, Data Link, Network, and Transport) are applied between the DOCSIS and CMTS
what information can be gathered by a return path monitoring system that captures the quadrature amplitude modulation (QAM) return channel from a do docsis modem?
PNM performs correlation of data from all the modems in the area to pinpoint where the likely problem in the network can be found
what did the 1.1 version of DOCSIS introduce, incorporating solutions for transporting real-time data applications (such as voice traffic) over the cable operators managed IP network, and doing so with quality comparable to the telephone company
PacketCable
which Open Systems Interconnection (OSI) reference model layers does the Media Access Control (MAC) Layer in the Data Over Cable Service Interface Specification (DOCSIS) overlap so that the media access control (MAC) can be used by the cable modem termination system (CMTS) to differentiate between cable modems?
Physical and Data Link Layers
why are the RF return channel carriers unusable for aligning return path equipment?
RF return channel carriers are of short duration and from multiple sources
what enables set-top boxes (STB) and data over cable service interface specification (DOCSIS) modems to operate as completly separate systems that operate independent of each other?
STB and DOCSIS modems are assigned different upstream channels with different upstream channels with dedicated receivers in the headend
which step in the troubleshooting process requires a discussion with the customer to gather more detail about the problem?
Step 1: Identify the problem
in addition to being accurate and detailed, a successful troubleshooter knows that
a critical step in troubleshooting is verifying the signal levels and signal quality at the tap to establish the baseline performance for the installation
what system is a byproduct of the "funneling effect" ?
a many-to-one system
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
as you prepare to setup the fiber optic network, you realize you need a coupler that will allow any of its ports to be used as either input or output. which coupler should you choose?
a reflective star coupler
what can be used with a signal meter (SLM) to check the drop system for RF continuity at sub-band frequencies?
a signal generator
the leakage detector calibration can be verified using the system's leakage carrier, a signal level meter, and
a variable attenuator
which advanced physical layer (PHY) technology developed and added to docsis 2.0 includes byte interleaving?
advanced time division multiple access (A-TDMA)
what access schemes were introduced with advanced physical (PHY) layer technologies in DOCSIS 2.0?
advanced time division multiple access (A-TDMA) and synchronous code division multiple access (S-CDMA)
the return amplifier
amplifies the return signals for transmission to the next return amplifier upstream relative to the forward path
which of the following devices is an active device?
an addressable tap
a passive component that reduces signal amplitude equally at all frequencies in a distribution amplifier is
an attenuation pad
what serves as an amplifier in fiber optic networks,allowing light signals to travel farther while retaining signal strength?
an erbium-doped fiber amplifier (EDFA)
how does the signal attenuation through coaxial cable in the sub-brand frequency spectrum compare to the attenuation at forward path frequencies?
at sub-band frequencies, the signal attenuation is significantly less than in the forward path
what location in the network is common path distortion (CPD) most severe?
at the output of a forward amplifier because the forward levels are highest and the return levels are lowest
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
why are the data throughput rates for both downstream and upstream in Data Over Cable Service Interface Specification (DOCSIS) networks asymmetrical?
because the narrower bandwidths and lower orders of modulation for the return path carriers cause the DOCSIS downstream and upstream data rates to be unequal or asymmetrical
where should the injected sweep pulses be placed to avoid interference with active return carriers when sweeping the return path?
between active return carriers only if there is adequate space to accommodate the bandwidth of the injected sweep pulses
what are the symptoms of hum on an upstream digital modulation channel?
bit errors occur , similar to impulse noise and ingress on the upstream path
when all other factors are equal, if the bonding wire and the cable connecting the drop cable to consumer electronics are the same size, which should be shorter in order to correctly bond the installation?
bonding wire
how is laser clipping in the return path characterized on a spectrum analyzer?
by an elevated noise floor above 42 MHz after the optical signal has been converted back to RF, typically in the headend
how can the amount of thermal noise added to a network be minimized?
by ensuring that the RF input is at or above the specified minimum input level to all amplifiers
on cable system design maps, standard symbols include
circle for a two-way tap, a square for a four-way tap, and a hexagon for an eight-way tap
In a Data Over Cable Service Interface Specification (DOCSIS) network, why is the data throughput over the return or upstream path typically less than the throughput of data over the forward or downstream path?
compared to the downstream path,cthe narrower bandwidths and lower orders of modulation used to transport data over the return patch cause the downstream and upstream data throughput to be unequal or asymmetrical
what criteria does the Data Over Cable Service Interface Specification (DOCSIS) certification process ensure?
compliance with the DOCSIS standard and interoperability between suppliers
what should be done before diagnosing a return path problem in the drop system?
confirm the hybrid/coax (HFC) network is working properly
a typical power inserter faceplate
contains electronic components, cover bolts, and interconnect pins
constant bit rate (CBR) telephone system is considered to be circuit-switching technology because the analog audio signal is
coverted into a digital DSO circuit and switched to other cable telephony customers or to the telephone company's network
The purpose of PacketCable is to
define the architecture for the delivery of real-time IP applications with service levels comparable to POTS
what evolved after the introduction of switched digital video (SDV) illustrated some limitations of legacy hybrid fiber coax (HFC) networks?
distributed access architecture (DAA)
fraction converted to a percent
divide number by denominator, multiply by 100
as cable companies have e pandemic their use of fiber optic cable, they have also brought it closer to the customer premises, increasing the bandwidth available to customers. which answer below best represents the progression of fiber optic network architecture?
fiber-to-the-feeder (FTTF), fiber-to-the-neighborhood (FTTN), fiber-to-the-curb (FTTC), fiber-to-the-home (FTTH)
which of the following statements is true?
for each power inserter, the system design must ensure that: (1) the current required by any on RF/AC port does not exceed that port's power-passing specification and (2) the current required by both RF/AC ports does not exceed the AC input port power-passing specification
house amplifiers with a passive return path are used for what type of situation?
for situations when long service drops are used and the forward path needs to be amplified but return path amplification is unnecessary
number that compares amount that is less than a whole to the whole
fraction
where do Data Over Cable Service Interface Specification (DOCSIS) modems receive their conffiles, billing system messages, and access control messages from?
from the cable modem termination system (CMTS), which interfaces with the operations support system (OSS) and acts as a proxy or messenger that transfers messages and files between the modems and their respective servers
directional tap that feeds a signal through to other taps
has a directional coupler portion that efficiently routes most of the signal to the output port while removing a small amount of the signal and passing it to the splitter network
RF/AC bypass tap
has the added feature of being able to maintain RF signal and AC voltage continuity during faceplate removal
In following the six step troubleshooting process, one of the first pieces of information to establish is
how many customers are affected in order to identify the issue to a specific customer premises or multiple customers
when should a preamplifier be used to measure impairments with a spectrum analyzer?
if the noise floor drops less than 10 dB when the input signal is removed from the spectrum analyzer
how is impulse noise characterized when viewed on a spectrum analyzer?
impulse noise will appear as random spikes of energy across the entire return path frequency spectrum ( 5MHZ - 42 MHZ)
in what applications are avalanche photodiodes (APD) most likely to be used?
in fiber-to-the-home (FTTH) architectures where high attenuation of optical splitters must be overcome
which of the following statements is true?
in general, the closer the tap is to the amplifier output port, the higher the tap value
what distinguishes a micro-reflection from other types of signal reflections?
in micro-reflections, the echoed signals arrive back at the source with a time delay relative to the incident or transmitted signal, ranging from nanoseconds (ns) to a few microseconds
what signal leakage information and measurements must be included with the annual reporting to the FCC?
information carried on signals in the aeronautical bandwidths
signal power level in a directional coupler
is greater at a 7 dB tap port than at a 12 dB tap port with the same input signal level
terminating tap
is the last tap installed at the end of the feeder cable run
which of the following describes a power inserter?
it contains a high-pass filter network that passes RF signals between the two RF/AC ports and blocks 60-Hz 60 VAC between the same two ports
when light strikes a medium at an angle less than the critical angle, what happens to the light?
it is reflected
What layers of the Open Systems Interconnection (OSI) reference model are specific to cable networks and are present only between Data Over Cable Service Interface Specification (DOCSIS) modems and the cable modem termination system (CMTS)?
layers 1 through 4 (Physical, Data Link, Network, and Transpirt) are applied between the DOCSIS modem and CMTS
why is a leakage detector preferable to a signal meter for detecting leakage?
leakage detector has an increased sensitivity to weak signals
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?
low value taps have less isolation between ports and offer less attenuation it ingress and impulse noise coming from an individual drop system
what are the units that can be used to represent signal level values
millionth (mV), decibel millivolt (dBmv), microwatt (uW), nanowatt (nW)
if a leak is at an amplifier location, which antenna would be best for more precise determination of the exact source?
near field probe
what recourse do broadband cable operators have if citizens band (CB) and ham radio signals ingress into their network?
none, as long as the radio transmissions are at or below legal power levels, it is the cable operators obligation to prevent these signals from entering their network
what should be done when the location of electrical interference in the power network is identified?
notify the power company with the exact location so the cause of the interference can be repaired
most line extender housings have...
one input port for receiving the forward RF signals and one or two output ports for distributing the amplified forward RF signals
What was introduced in Data Over Cable Service Interface Specification (DOCSIS) 3.0 to allow enough bandwidth for upstream carriers from previous DOCSIS versions?
option to increase the top frequency of the upstream to 85 MHz
what are two features that were added in Data Over Service Interface Specification (DOCSIS) 3.1 to extend the viability of hybrid fiber/coax (HFC) networks into the next decade?
orthogonal frequency division multiplexing (OFDM) and low density parity check (LDPC)
what features were introduced with the 3.1 version of the Data Over Cable Service Interface Specification (DOCSIS 3.1) to increase the downstream and upstream data throughput?
orthogonal frequency division multiplexing (OFDM) and low density parity check (LDPC)
line extender amplifier housing has...
plug-in connectors that direct the incoming forward RF signals from the input port to the RF amplifier module and the outgoing amplified signals from the amplifier module to the output port
what practice can uncover potential return path problems in the drop system that can be mitigated before entering the network?
prescreening the drop system for ingress and egress
DOCSIS 1.1 added Service Flow to its media access control (MAC) protocol to
provide a mechanism for upstream and downstream quality of service management
which type of digital modulation contains 4 symbols with 2 bits in each symbol?
quadrature phase shift key (QPSK)
what requirements were needed for PacketCable to deliver a quality and reliable telephone service over a Data Over Cable Service Interface Specification (DOCSIS) access network?
quality of service (QoS) controls, enhanced security, and adaptive equalization in the upstream path
what are the FCC requirements regarding leakage monitoring?
quarterly monitoring and annual reporting
why is it imperative to keep all ingress and impulse noise, even that outside of the frequency range of the RF return carriers, to a minimum?
regardless of the frequency, if the impulse noise or ingress is high enough, it can cause laser clipping
the line extender amplifier...
requires the AC input voltage typically to be received through the port seizure screw
the impedance of coaxial cable or a device is made up of the combined effects of which three electrical properties?
resistance, inductance, and capacitance
what is the one limitation of fabry-Perot (fp) lasers that is eliminated in distributed feedback (DFB) lasers?
side modes
tap loss is...
signal attenuation between the input port and each tap port at a specific frequency
when adjusting amplifier controls, remember that
signal level controls compensate for slight variations in the input signal level caused by temperature changes and by signal loss from coaxial cable and passive devices
what is the definition of tap value?
signal loss between the tap input portand the tap ports
what is ingress?
signals leaking into the cable system
which technology will carry a signal the greatest distance without a repeater?
single mode
what amplitude level should the output of return amplifier be adjusted?
so that the amplifier gain is equal to the path attenuation that follows the amplifier
what is it necessary in the optical return path to get the most performance from the DOCSIS 3.1 specification?
some combination of higher transmit power, more sensitive receivers, and lower path loss
directional coupler
tap port leg can supply signal to a multiple dwelling unit (MDU) or a smaller number of customers whole maintaining the maximum amount of signal on the original cable
signal attenuation between two individual customer tap ports at a specific frequency, with all other ports terminated, is the definition of
tap-to-tap isolation
what is the primary difference between coaxial express cable and coaxial distribution cable in an HFC architecture?
taps are installed on coaxial distribution cable and not on express cable
"bel" originated with
telephone
when looking at the cable model's PreEqualization tap response, what do you know if the ninth bar is less than 10 dB below the eighth bar?
that their are high micro-reflections and that the cause is near the modem, likely in the drop
when comparing different sizes of directional coupler with identical input signal levels
the DC-12's resulting tap port signal voltage levels are lower and output port signal voltage levels are higher than the respective port output levels for DC-7
why is installing high-class filters (HPF) at the tap on drops without two-way services considered a short-term solution to ingress and impulse noise migrating into the hybrid fiber/coax (HFC) network?
the HPF will have to be removed when cable modems and digital set-top boxes (STB) are activated at the address that have an HPF installed
what does the spectrum analyzer Zero Span function do?
the Zero Span function stops the analyzer's sweep and parks its tuner to a specific frequency, displaying amplitude vs time
which optical band is used for optical amplifiers due to the attenuation loss and availability of economical optical fibers?
the c band
what is reported when the signal level meter (SLM) in a return path alignment system displays the return test carriers as a delta measurement?
the calculated difference between the configured input and the recieved input
what type of measurement removes any errors attributable to bandwidth and provides an "apple's to apples" comparison between carriers of differing bandwidths?
the constant power per Hertz (power/Hz) measurement
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 data throughput dobles
in the forward signal path of the line extender
the first equalizer is where the frequency dependant attenuation (tilt) caused by the coaxial cable between the line extender and the previous upstream amplifier is corrected
why is the broadband cable industry developing its own passive optical network (PON) standard instead of using standards already developed by the International Telecommunications Union (ITU) and the Institute of Electrical and Electronics Engineers (IEEE)?
the industry has invested a lot of money in HFC networks, Data Over Cable Service Interface Specification (DOCSIS), and other systems and devices that are still currently being used, but they are not compatible with ITU and IEEE PON standards
what spectrum analyzer function is particularly useful as it captures and holds ingress, impulse noise, and other impairments on its display so they can be viewed and analyzed?
the max hold function
what enables the set-top box (STB) upstream carrier to be located below 20 MHz and still be reliably received?
the narrow bandwidth and quadrature phase shift keying (QPSK) modulation
you are doing an aerial installation of fiber optic cable. when you survey the installation path, you see that the path runs near several outbuildings and over a series of hedges. which installation method should you use?
the pull-in method
in a traditional analog return, the optical dectors are responsive to the power of the recieved signal. how does the signal level at the output of the upstream recicer relate to changes to its input power?
the signal level at the output of the upstream receiver changes 2 db for every 1 db of received optical power level
operational gain is...
the signal level difference between the input signal and the output signal
when analyzing a problem, what can the technician learn by asking the customer to show or demonstrate the problem?
the symptoms of the problem can be viewed and any unusual screens or customer entries can be identified
three components of the tap housing (and not the tap faceplate) are
the threaded mounting tap, seizure screw mechanism, and right-angled input and output ports
the "bypass AC current capacity" is...
the total AC current the line extender amplican pass through to other active devices
why is 38 MHZ typically the highest frequency in the sub-brand frequency that 8s used for upstream modem transmissions?
the upper edge of the sub-frequency spectrum is prone to group delay caused by the duplex filters
what should be checked if a large percentage of set-top boxes (STB) transmit above 55 dBmV, the upper end if the STB transmission level range
the value of attenuator pad at the input of the STB demodulator
why is the E band undefined for fiber-optics communications?
there is a lot of older fiber-cable still in use that may have unacceptable water-peak attenuation
why are 6 MHz and 41 MHz good choices for test carriers when injecting test carriers into a return path spectrum of 5 MHz to 42MHz?
these frequencies are at the edges of return frequency spectrum and are available
what should be done about injected test carriers at the node appearing at the transceiver in the headend with a frequency response variations if less than 1 dB?
these variations are normal and can usually be disregarded
values expressed in dBmV progress in a nonlinear fashion because
they are based on logarithms of power ratios
what is a characteristic of orthogonal frequency division multiplexing (OFDM) channel subcarriers?
they can be modulated at maximum order of modulation for a given bandwidth that is suitable for the condition if the network
when closing any distribution amplifier housing...
tighten the bolts to the recommended torque in the power tightening sequence, using an appropriate torque wrench
what communications access technology does the first version of the Data Over Cable Service Interface Specification (DOCSIS 1.0) use to send data upstream over the network's radio frequency (RF) return path?
time division multiple access (TDMA)
which testing device is the best to use to measure cable faults?
time domain reflectometer (TDR)
which of the following is true?
to calculate the directional coupler output port and tap port signal levels in dBmV, first obtain the manufacturer's specifications for insertion losses
why does output level from customer premises equipment (CPE) vary?
to compensate for variable amounts of attenuation in the return path of each device
in a fiber optic cable, what is the purpose of the cladding?
to guide light down the fiber
in the traditional analog return path, what is critical about the upstream optical transmitter?
to make RF level into the upstream transmitter is correct
what is the best explanation of the function cladding performs in a fiber optic cable?
to reflect light as it passes through a cable
what purpose do duplex filters fulfill when installed at the input and output of a two-way amplifier module?
to route the forward and return signals over different circuit paths to the appropriate section so that they can be amplified separately
it is important to follow safety procedures when installing and handling fiber optic cable. what should you use to pick up fiber pieces after you splice a cable?
tweezers
in the term 10BaseT what does the T mean?
twisted pair
values expressed in dBmV that are preceded by a minus sign represent
voltage less than 1 mV across 75 ohms
which of the following is the distance occupied by 1 hertz (Hz)?
wavelength
which of the following is used to define the waveform of an optical signal?
wavelength
when is the return path considered to be properly balanced with unity gain?
when the test carriers injected into the last amplifier in the cascade reach the transceiver I. the headend with the same level as from the node
when is UTP cable preferred over STP?
when there is little electrical interference
poor performance in the fiber optic network leads you to believe that there is a fault in the fiber optic cable and you want to test a section of the network with an optical time domain reflectometer (OTDR). how should you connect the OTDR to the fiber optic cable?
with an optical mechanical splice
chipsets with ingress cancellation algorithms are most effective for removing impairments in what portion of the RF return frequency spectrum?
within the upstream channel bandwidth