System Technician Conventional UPDATED ACTUAL Questions And Correct
Answers
Terms in this set (72)
Chapter 7 Chapter 7
In a broadband cable network, where would a block At the node
convertor be most likely used?
What is sent with digital TV (DTV) transmissions that A 27 MHz program clock reference (PCR)
enables the receiver to synchronize with the sending
device to decode and place the data in the correct
sequence?
What risk is there in coupling the output of an oscillator The oscillator frequency could be changed (or pulled by) the next circuit stage.
to another circuit stage?
What is the primary difference between the Hartley and The Colpitts oscillator uses capacitive feedback, and the Hartley uses inductive
Colpitts oscillator circuits? feedback.
Which must be done to create an oscillator if the circuit Another 180-degree phase shift is necessary for positive feedback.
transistor is in the common emitter configuration?
When included in an oscillator circuit, what component A varactor (or varicap) diode.
enables the oscillator frequency to be controlled by
voltage, hence, the voltage controlled oscillator (VCO)?
What is significant about how a crystal is cut with respect The cut dictates pretty much all crystal characteristics, including frequency drift
to the orientation of the quartz crystal lattice structure? with temperature.
Which resonant circuit mode of a crystal should be used Series resonant.
in applications in which frequency accuracy is most
important?
When is a temperature-controlled crystal oscillator When techniques to compensate for crystal drift are inadequate for the
(TCXO) likely to be used? application.
What is a characteristic of the monostable multivibrator? When given a suitable input signal, it generates a single pulse of fixed length.
Describe an application for a distribution amplifier in a To maintain downstream amplitude levels to the addresses farthest from the fiber-
hybrid fiber/coax (HFC) network? node.
In a distribution amplifier, why is the frequency response To reduce intermodulation distortion levels caused by amplifying high amplitude
at the input of the second output stage sloped input levels.
, What is installed in the input stage of a distribution A cable equalizer with positive slope.
amplifier for a flat frequency response into the input
amplifier when the input signal has negative tilt?
Why is the term "gain control" applied to amplifier gain The only way to vary the output of any amplifier is to adjust the amplitude level of
and controls inaccurate? the signal going into the amplifier.
How is the AC voltage separated from the RF signal in a By a capacitor that passes RF but blocks the low frequency 60 hertz (Hz) AC
distribution amplifier? voltage which finds a low resistance path through the RF choke that blocks RF.
What is the expected DC voltage on most hybrid fiber +24 VDC, ± 0.5 V.
coax (HFC) network equipment?
What term describes the frequency spectrum into an Negative tilt.
amplifier having higher amplitude at low frequencies than
the high frequencies?
When configuring the input stage of a distribution The input equalizer and attenuator pad values.
amplifier, what element values can vary from those in the
amplifier tombstone, depending on the input amplitude
measurements?
What value of interstage equalizer should be installed if Factory
the associated amplifier tombstone field is blank and the
amplifier output slope is 7 dB?
When configuring the upstream return in a distribution The distribution amplifier upstream port with the most attenuation in its upstream
amplifier with multiple upstream ports, the amplitude path.
levels for which port should be adjusted first?
Which of the following describes reactive maintenance? Network activity initiated by metrics that show degraded service performance.
In addition to device and network parameters from Analysis of the data along with network topology and device location.
DOCSIS modems, what information is needed to isolate
the source of a problem in the network?
Why are micro-reflections some of the more difficult Because they require physical inspection of the connectors and cable to find.
issues to diagnose?
A micro-reflection signature consists of what pair of The relative level of the reflected signal compared to the main signal, and the
characterizing elements? delay of the reflected signal.
When setting proactive network maintenance (PNM) 3 dB.
severity metrics for main tap ratio (MTR), how much level
change is typically worthy of attention?
When there is reflection indicated by an adaptive By dividing the time delay between the reflection and the incident signal by the
equalize, how do test instruments calculate the unknown cable velocity of propagation (VoP) per 100 feet.
distance to a reflection?
Answers
Terms in this set (72)
Chapter 7 Chapter 7
In a broadband cable network, where would a block At the node
convertor be most likely used?
What is sent with digital TV (DTV) transmissions that A 27 MHz program clock reference (PCR)
enables the receiver to synchronize with the sending
device to decode and place the data in the correct
sequence?
What risk is there in coupling the output of an oscillator The oscillator frequency could be changed (or pulled by) the next circuit stage.
to another circuit stage?
What is the primary difference between the Hartley and The Colpitts oscillator uses capacitive feedback, and the Hartley uses inductive
Colpitts oscillator circuits? feedback.
Which must be done to create an oscillator if the circuit Another 180-degree phase shift is necessary for positive feedback.
transistor is in the common emitter configuration?
When included in an oscillator circuit, what component A varactor (or varicap) diode.
enables the oscillator frequency to be controlled by
voltage, hence, the voltage controlled oscillator (VCO)?
What is significant about how a crystal is cut with respect The cut dictates pretty much all crystal characteristics, including frequency drift
to the orientation of the quartz crystal lattice structure? with temperature.
Which resonant circuit mode of a crystal should be used Series resonant.
in applications in which frequency accuracy is most
important?
When is a temperature-controlled crystal oscillator When techniques to compensate for crystal drift are inadequate for the
(TCXO) likely to be used? application.
What is a characteristic of the monostable multivibrator? When given a suitable input signal, it generates a single pulse of fixed length.
Describe an application for a distribution amplifier in a To maintain downstream amplitude levels to the addresses farthest from the fiber-
hybrid fiber/coax (HFC) network? node.
In a distribution amplifier, why is the frequency response To reduce intermodulation distortion levels caused by amplifying high amplitude
at the input of the second output stage sloped input levels.
, What is installed in the input stage of a distribution A cable equalizer with positive slope.
amplifier for a flat frequency response into the input
amplifier when the input signal has negative tilt?
Why is the term "gain control" applied to amplifier gain The only way to vary the output of any amplifier is to adjust the amplitude level of
and controls inaccurate? the signal going into the amplifier.
How is the AC voltage separated from the RF signal in a By a capacitor that passes RF but blocks the low frequency 60 hertz (Hz) AC
distribution amplifier? voltage which finds a low resistance path through the RF choke that blocks RF.
What is the expected DC voltage on most hybrid fiber +24 VDC, ± 0.5 V.
coax (HFC) network equipment?
What term describes the frequency spectrum into an Negative tilt.
amplifier having higher amplitude at low frequencies than
the high frequencies?
When configuring the input stage of a distribution The input equalizer and attenuator pad values.
amplifier, what element values can vary from those in the
amplifier tombstone, depending on the input amplitude
measurements?
What value of interstage equalizer should be installed if Factory
the associated amplifier tombstone field is blank and the
amplifier output slope is 7 dB?
When configuring the upstream return in a distribution The distribution amplifier upstream port with the most attenuation in its upstream
amplifier with multiple upstream ports, the amplitude path.
levels for which port should be adjusted first?
Which of the following describes reactive maintenance? Network activity initiated by metrics that show degraded service performance.
In addition to device and network parameters from Analysis of the data along with network topology and device location.
DOCSIS modems, what information is needed to isolate
the source of a problem in the network?
Why are micro-reflections some of the more difficult Because they require physical inspection of the connectors and cable to find.
issues to diagnose?
A micro-reflection signature consists of what pair of The relative level of the reflected signal compared to the main signal, and the
characterizing elements? delay of the reflected signal.
When setting proactive network maintenance (PNM) 3 dB.
severity metrics for main tap ratio (MTR), how much level
change is typically worthy of attention?
When there is reflection indicated by an adaptive By dividing the time delay between the reflection and the incident signal by the
equalize, how do test instruments calculate the unknown cable velocity of propagation (VoP) per 100 feet.
distance to a reflection?
