Troubleshooting and Maintenance
At what layer of the OSI model is a technician working on when they are replacing a hardline connector?
1 physical
signal leakage limits 54-216 mhz
20 μV/m at a distance of 10 ft
characteristic impedance
75 ohms
An FVD can be used to test for the presence of _______________.
ac
What device is a good mid-point to use when applying divide and conquer to the distribution network?
amp
For a digital channel what portion of the signal will it use for the RF power level measurement?
center frequency of the channel
Visual display of modulation errors on a QAM signal.
constellation
why are channel plans important?
correct plan ensures meter has correct frequency and modulation type for each rf channel used in a system
What test is used to obtain the transmit power level?
docsis
How often is a cable company required to do a ride out through the entire system
every 3 months
CTB and CSO measurements can only be taken on digital signals.
false
If the RF signal level is within specifications, it is not necessary to check any other signal performance metrics such as MER and BER.
false
A MOS score of 2.5 or greater is considered acceptable.
false - mean opinion score, quality of voip - 3.1 minimum
What tool should be used with a signal leakage detector in order to get the most precise measurement?
half-wave dipole antenna
Beside new detection equipment in the field, what other equipment is needed to test for signal leakage in a digital system?
headend eq to add detection signal
The picture on all TVs at the customer premises fluctuates from good to bad. Which item could be the cause?
house amp plugged into switch outlet
what 3 devices can provide PNM data?
modem, emta, stbs - cablecards cannot
reduce ingress - several points
proper craftsmanship cables meeting specs equipment not damaged, meets specs TEST
The type of meter used to test downstream digital signal quality such as BER, MER or constellations, is called:
qam analyzer
A VOM or DMM can be used to test phone line:
shorts/opens
A ___ is a device or tool that displays a plot of signal frequency versus signal amplitude, used to verify frequency response.
spectrum analyzer
Device used to locate damage, transmission line discontinuities, or impedance mismatches in coaxial cable by using distance and phase is called:
tdr
What happens when the MER falls into the digital cliff range?
tiling
The tool used to identify specific wires of twisted pair or station wire and their route at the location is called:
tone and probe kit
A cable locator can be used to locate buried coaxial cable.
true
An audible alert occurs when 50 VAC is detected.
true
By comparing Pre and Post BER, a technician can determine if FEC is able to correct the problems encountered in the cable system.
true
If the downstream RF signal level is not within specifications, you must be address this problem before proceeding any further with the CPE.
true
True or False: A line loop tester or brown meter finds faults in the telephone wires of the customer's home.
true
True or False: Group delay is defined as the rate of change of phase with respect to frequency, the amplitude ripple produces fine-grained phase ripple, which in turn may result in large group delay ripple.
true
True or False: The FCC rules require that all signal leakage of 20uV/meter measured at a distance of 10 feet in the aeronautical bands, must be logged and repaired.
true
You can use a toner and probe to determine the twisted pair cable that is connected to the eMTA.
true
what 4 tests can be done by whole home certification?
up/down quality, moca frequency response, ingress
For an analog channel what portion of the signal will it use for the RF power level measurement?
video carrier
The ___ ___ ___ is required to accurately use a TDR or OTDR.
vop velocity of propagation - rf speed relative to speed of light in a vacuum
What is the comparison between the speed at which a signal propagates down the cable compared to the speed of light in a vacuum?
vop velocity of propagation
Twisted pair wire bundles require a ___ for wire identification.
wire mapper
