Test Help

QPSK delivers two bits of data at one time, enabling the delivery of data at a higher throughput but in more bandwidth than FSK.

QPSK delivers two bits of data at one time, enabling the delivery of data at a higher throughput and in less bandwidth than FSK.

QPSK delivers four bits of data at one time, enabling the delivery of data at a higher throuqhput but in more bandwidth than FSK.

QPSK delivers four bits of data at one time, enabling the delivery of data at a higher throughput and in less bandwidth than FSK.

Four data symbols containing two bits of data that can be transported over a noisy network and still be decoded by the receiver.

Two data symbols containing four bits of data that can be transported over a noisy network and still be decoded by the receiver.

Two data symbols containing four bits of data that can be transported over a noisy network and still be decoded by the receiver.

Four data symbols containing two bits of data that require low noise levels in the transport network In order to be decoded by the receiver.

Unnecessary .sidebands and harmonics that could interfere with other carriers are suppressed, but additional RF bandwidth is gained for a given symbol rate.

Unnecessary sidebands and harmonics that could interfere with other carriers are suppressed, and the RF bandwidth is equal to the symbol rate.

Unnecessary sidebands and harmonics that could interfere with other carriers are suppressed, and the RF bandwidth is narrowed to a value less than the symbol rate

Unnecessary sidebands and harmonics that could interfere with other carriers are suppressed but additional RF bandwidth is required for given symbol rate

Eight bits of data representing the decimal values 0 through 63

Two bits of data representing the decimal values 0 through 63.

Six bits of data representing the decimal values 0 through 63.

Four bits of data representing the decimal values 1 through 63.

The transmitted data frames include the transmission frequencies, the modem DOCSIS address, and the usage intervals for each particular cable modem.

The transmitted data frames include the transmission frequencies, time references, and the MAC address for each particular cable modem.

The transmitted data frames include collision detection, time references, and the usage intervals for each particular cable modem.

The transmitted data frames include the transmission frequencies, time references, and the usage intervals for each particular cable modem.

The MAC assigns priority tags to each packet which is used to shape police, and prioritize Internet protocol (IP) traffic according to the application's quality of service (QoS) traffic parameters.

The MAC sends a scouting message to determine the fastest and most direct route through the network for real-time applications.

The MAC assigns additional RF bandwidth and symbol rates to each packet according to the application's quality of service (QoS) traffic parameters.

The MAC assigns a priority Internet protocol (IP) address to the modem so that any data is routed through the network ahead of traffic from non-priority IP modems.

Ingress cancellation only removes ingress or common path distortion(CPD)that is on a return carrier ingress or CPD that falls between carriers still remains and can still cause problems. problems.

Ingress cancellation uses proprietary techniques and is only effective with specific cable modems.

Ingress cancellation only removes ingress or common path distortion (CPD) that falls between return carriers; ingress or CPO that falls on return carriers still remains and can still cause problems.

Ingress cancellation uses proprietary techniques and Is only effective with specific cable modem termination systems (CMTS).

16-QAM (quadrature amplitude modulation).

Frequency shift keying (FSK).

Phase shift keying (PSK).

Quadrature phase shift keying (QPSK).  

Increase the amplitude of the RF carrier.

Increase the number of bits per symbol from two to four.

Increase the RF transmission frequency.

Increase the RF bandwidth.

Advanced Physical Layer (PHY) technologies and the use of one of two traffic access       schemes, time division multiple access (TDMA) or synchronous code division multiple access (S   -COMA).               Advanced Physical Layer (PHY) technologies and the use of one of two traffic access       schemes, time division multiple access (TOMA) or synchronous code division multiple access (S   -COMA).                  

Advanced Physical Layer (PHY) technologies and the use of one of two traffic access schemes, advanced time division multiple access (A-TDMA) or carrier sense multfple access with collision detection (CSMA/CD).

Advanced Phvsical Layer (PHY) technologies and the use of one of two traffic access schemes, advanced time division multiple access (A- TDMA) or synchronous code division multiple access (S-CDMA).

Advanced Physical Layer (PHY) technologies and the use of one of two traffiC access \ schemes, advanced frequency division multiple access (A-FOMA) or synchronous code division multiple access (S-COMA).

700 nm, 1,300 nm, 1,550 nm, and 1,625 nm.

380 nm, 700 nm, 1,550 nm, and 1,625 nm.

850 nm, 1,300 nm, 1,550' nm, and 1,625 nm

380 nm, 1,300 nm, 1,550, and 1,625 nm.

DFB lasers use external modulation which enables suppression of wavelengths other than the center wavelength.

DFB lasers distribute and electronically feed back undesired wavelengths to maximum the output of the laser but minimize the MPN.

DFB lasers electronically feed back all of the undesired wavelengths out of phase on top of one another to cancel them out

DFB laser  have an additional structure that  suppresses wavelengths other than the center wavelength.

The laser goes into nonlinear operation and the (NPR) drops off dramatically.

The laser goes into linear operation and the NPR drops off dramatically.

The laser goes into linear operation and the NPR improves dramatically.

The laser goes into nonlinear operation and the NPR improves dramatically.

The RF output level from the optical receiver should be adjusted only after the optical power through the shortest optical path has been established.

The RF output level from the optical receiver should be adjusted only after the optical power into the receiver has been established. 

The RF output level from the optical receiver should be adjusted only after the optical power into the laser has been established.

The RF output level from the optical receiver should be adjusted only after the optical power through the longest optical path has been established.

The input to the RF amplifier should be adjusted for the correct RF output from the optical receiver.

The RF amplifier should have minimal input attenuation, so the output power should be adjusted using external attenuation between the receiver's RF output and the first RF splitter in the headend distribution network.

The RF amplifier should have minimal input attenuation, so the RF power Into the laser should be adjusted for the correct RF output from the optical receiver

The RF amplifier should have minimal input attenuation, so the optical attenuators should be used to adjust the RF output power from the optical receiver

Optical demultiplexing requires a specialized receiver to convert all the optical wavelengths into a single RF channel

Optical demultiplexing uses fiber Bragg amplifiers to separate the different wavelengths of optical signals through an optical fiber.

Optical demultiplexing use optical filter to separate the different wavelengths of optical signals through an optical fiber

Optical demultiplexing uses optical splitters to feed a portion of the optical signals to dedicated optical receivers

Following the Nyquist sampling theorem, the sampling rate must be equal to or less than that of the highest frequency contained in the analog return path signal.

Following the Nyquist sampling theorem, the sampling rate must be greater than twice that of the highest frequency contained in the analog return path signal

Following the Nyquist sampling theorem, the sampling rate must be greater than four times that of the highest frequency contained in the analog return path signal

Following the Nyquist sampling theorem, the sampling rate must equal to or greater than that of ~he highest frequency contained in the analog return path signal

Service penetration, the density of the customer base, and the distance the return signals need to be carried

Service penetration, the density of the customer base, and the distance the forward signals need to be carried.

Service penetration, the affluence of the customer base, and the distance the return signals need to be carried

Service penetration, the density of the return channels, and the distance the return signals need to be carried

DWDM converts blocks of multiple return path signals to a single digital signal digital signal before transport through the optical network.

DWDM uses a multiplexer with a narrow range of wavelengths inside the C-band.

DWDM converts blocks of multiple return paths to higher frequency bands and sequentially stacks them on top of one another

DWDM provides only two optical channels in either the 1,310 or 1,550 nanometer (nm) light spectrum.

The best optical link performance occurs when the input power to the laser causes the NPR to be on the gradual rise (left side) of the curve, at least 10 dB below the highest NPR level.

The best optical link performance occurs when the input power to the laser causes the NPR to be at the peak of the NPR curve.

The best optical link performance occurs when the input power to the laser causes the NPR to be on the gradual rise (left side) of the curve, just below the highest NPR level.

The best optical link performance occurs when the input power to m"e laser causes the NPR to be on the sharp decline (right side) of the curve just below the highest NPR level

The output of the amplifier should be reduced by instaIIing a 2 dB attenuator pad to the amplifier's output.

Replace the internal amplifier stage with one that has only 18 dB of gain.

The output of the amplifier should be reduced by installing a 2 dB attenuator pad in the amplifier's input stage

The output of the amplifier should be decreased by replacing the internal port director with one having 2 dB more attenuation in the signal path

A high percentage of cable modems are transmitting at their maximum output level.

The output levels from the return amplifiers are 3 dB low.

The cable modems are operating fine, but the set-top boxes (STB) are not responding to polls.

A high percentage of cable modems are transmitting at their minimum output level

Because forward carriers are not always present making it difficult to measure carrier levels in and out of a return amplifier.

Because return carriers only operate at 20 dBmV, repeat every 300 milliseconds and occupy 18 MHz

Because return carriers are always present making it difficult to measure carrier levels in and out of a return amplifier.

Because return carriers are not always present making it difficult to measure carrier levels in and out of a return amplifier.

To determine the gain of the amplifier installed in the return section of the amplifier module.

To determine the signal flow through the amplifier module and to identify where to inject the test carriers.

To determine the type of mechanism used to direct signal flow through the amplifier module.

To determine what value attenuator pad and equalizer should be installed in the return section of the amplifier module.

The technician must calculate the difference between the measurements of a single path number and that of multiple paths funneling into the transceiver.

The technician must calculate the difference between the specified input to the transceiver and the  measured input.

The technician must ca cu ate the bandwidth correction for a quadrature amplitude modulation (QAM) carrier.

The technician must calculate the bandwidth correction for cumulative carriers being received by the transceiver.

Place the sweep pulses every 6 MHz from 5 to 42 MHz to avoid interfering with the quadrature amplitude modulation (QAM) carriers

Place the sweep pulses at the center frequency of each of the quadrature amplitude modulation (QAM) carriers to avoid interference.

Place the sweep pulses 4.5 MHz above the center frequency of the quadrature amplitude modulation (QAM) carriers to avoid interference.

Place the sweep pulses between the quadrature amplitude modulation (QAM) carriers to avoid interference.

Consider the voltage at the power inserter test point

Consider any attenuation such as a splitter, that may exist between the signal level meter (SLM) and the test point.

Consider the output power of the laser and all Insertion losses in the path to the optical path to the headend.

Consider the amplitude of the input signal reaching the amplifier from all the customer premises equipment (CPE).

The normalized reference establishes a baseline sweep response that is used to compare and adjust all the subsequent amplifiers in a specific return path.

The normalized reference establishes a baseline sweep response that is used to establish the power level into the return laser.

The normalized reference establishes a baseline sweep response that is used to compare and adjust all the frequency response of all the return lasers.

The normalized reference establishes a baseline input into the cable modem termination system (CMTS) that is used to establish the power output from the cable modems.

Distribution amplifiers typically have multiple return paths coming from different nodes at different amplitude levels.

Distribution amplifiers typically have multiple return paths which may contain different amounts of attenuation.

Distribution amplifiers typically have multiple return paths which have dedicated amplifiers for each path.

Distribution amplifiers typically have multiple return paths which contain equal amounts of attenuation.

Install a return equalizer closest to the value of the tilt.

Install a return equalizer 20 dB more than the value of the tilt.

Install a return equalizer half the value of the tilt.

Install a return equalizer double the value of the tilt.

Attenuation in the return path is primarily due to the passive devices.

Attenuation in the return path is primarily due to fiber-optic cable.

Attenuation in the return path is primarily due to the active devices.

Attenuation in the return path is primarily due to the coaxial cable

Long-loop AGC adjusts the receive levels of the customer premises equipment.

Long-loop AGC adjusts the transmit levels from the headend to the customer premises equipment.

Long-loop AGC adjusts the transmit levels of the customers premises equipment.

Long-loop AGC adjusts the receive levels from the headend to the customer premises equipment.

Each return amplifier must be adjusted so that the levels received at the next amplifier are within 15 dB of each other

Each return amplifier must be adjusted by the decibel (dB) value of the directional coupler (DC).

Each return amplifier must be adjusted so that the levels received at the next amplifier are 25 dbmv.

The output of each return amplifier must be adjusted so that the input levels received at the next amplifier are the same.

Most cable modems are configured to operate above 28 and below 38 MHz

Most cable modems are configured to operate above 5 and below 20 MHz

Most cable modems are configured to operate above 38 and below S4 MHz.

Most cable modems are configured to operate above 38 and below 42 MHz

The drop cable loss is 3.2 dB plus 7.0 dB (the loss of a three-way splitter) plus 9 dB (directional coupler loss), for a total of 19.2 dB in drop return path loss.

The drop cable loss is 3.2 dB minus 3.5 dB (the hot-leg loss of a three-way splitter) plus 9 dB (directional coupler loss) for a total of 8.7 dB In drop return path loss.

The drop cable loss is 3.2 dB plus 3.5 dB (the hot-leg loss of a three-way splitter) plus 9 dB (directional coupler loss), for a total of 15.7 dB in drop return path loss.

The drop cable loss is 3.2 dB plus 3.5 dB (the hot-leg loss of a three-way splitter) minus 9 dB (directional coupler loss), for a total of -2.3dB in drop return path loss.

Unpowered house amplifiers that reflect signals back to their source.

Loose or bad connections at the tap or nonterminated splitter ports in the drop system.

The use of splitters instead of directional couplers in the drop system.

Overloaded input levels to a house amplifier that are reflected back to their source.

Impulse noise can be reduced by locating taps and splitters close to switching power supplies.

Impulse noise can be reduced by tightening all connections and installing 75omb  terminators on unused taps.

Impulse noise can be reduced by tightening all connections and installing 10 dB "1 S~ ~ ~ attenuator pads on all used taps.

Impulse noise can be reduced by transmitting power on the distribution amplifiers.

At the coax interface on the node.

At the headend.

The customer premises and the drop cable

At the distribution amplifier.

Window filters act on specific frequencies from 5-42 MHz

Window filters act on specific frequencies above 5-42 MHz

High-pass filters block all frequencies above 108 MHz

Step attenuators provide 100 dB of attenuation on frequencies from 5-42 MHz

Installing high-pass filters on all unused tap ports

Installing high-pass filters on tap ports that are 17 dB or less

Replacing tap plates of 17db or less with higher value tap plates

Installing terminators on all unused tap ports

The transmission level of the cable modem Is controlled and adjusted by the HFC network return amplifier's automatic gain control (AGC), so the modem's operation is dependent on the stability of the HFC network.

The transmission level of the cable modem is controlled and adjusted by the return amplifiers in the HFC network, so the modem's operation is dependent on the stability of the HFC network.

The transmission level of the cable modem is controlled and adjusted by the number of carriers in the HFC network, so the modem's operation is dependent on the stability of the HFC network.

The transmission level of the cable modem Is controlled and adjusted from the headend over the HFC network, so the modem's operation is dependent on the stability of the HFC network.

The cable modem emulator must be registered with the cable operator's billing system as before it can be used to check the operations of a cable modem

The cable modem emulator must be registered with the cable modem termination system (CMTS) before it can be used to check the operations of a cable modem

The cable modem emulator must be added as a feature of the signal level meter by the cable operator's billing system before it can be used to check the operations of a cable modem.

The cable modem emulator must be registered with the emulator supplier before it can be used to check the operations of a cable modem

In a return path sweep and alignment system the transceiver receives and measures the test carrier that are injected into the  return path from a signal level meter (SLM), then sends the measurements to the SLM via the forward path on a telemetry carrier.

In a return path sweep and alignment system the transceiver sends the test carriers that are injected into the return path to a signal level meter (SLM) that sends a receipt message via the return path on a telemetry carrier to the transceiver as confirmation that the test loop is complete.

In a return path sweep and alignment system the transceiver sends and receives the test carriers that are used to test and troubleshoot the return path through the network.

In a return path sweep and alignment system the transceiver receives and measures the test carriers that are injected into the return path by the cable modems and set-top boxes (STB), then sends the measurements to the SlM via the forward path on a telemetry carrier

By capturing the QAM return carrier from a DOCSIS modem, QAM analysis can be used to j determine the modem's return path data throughput.

By capturing the QAM return carrier from a DOCSIS modem, QAM analysis can be used to troubleshoot the cause of linear distortions ( group delay, in-band ripple/tilt, and micro reflections) on a single QAM carrier in the  return path.

By capturing the QAM return carrier from a DOCSIS modem, QAM analysis can be used to pinpoint sources of ingress in the drop system.

By capturing the QAM return carrier from a DOCSIS modem, QAM analysis can be used to troubleshoot the cause of nonlinear distortions (group delay, common path distortion, and micro reflections) on a single QAM carrier in the return path

Decreasing the path attenuation in the drop system can increase the C/N of the drop system since the output of the modem/STB is increased to compensate for the lower attenuation by the long-loop automatic gain control (AGC).

Adding to the path attenuation in the drop system can increase the c/n of the drop system by attenuating any noise if the output of the modem/STB is increased to compensate for the added attenuation by the Iong - loop automatic gain control (AGC).

Adding to the path attenuation in the drop system can increase the C/N of the drop system by attenuating any noise if the output of the modem/STB is decreased to compensate for the added attenuation by the long-loop automatic gain control (AGC).

Decreasing the path attenuation in the drop system can increase the C/N of the drop system since the output of the modem/STB is decreased to compensate for the lower attenuation by the long-loop automatic gain control (AGC)

Look for elements that cause extra attenuation to the return path signal from the STB outlets. If nothing obvious Is identified during the Inspection, check the splitter/DC configuration for excessive attenuation in the return path of the STB outlets.

Look for elements that amplify the return path signal from the STB outlets. If nothing obViOUSis identified during the inspection, check the splitter/DC configuration for excessive attenuation in the return path of the cable modem

Look for elements that cause extra attenuation to the return path signal from the cable modem outlet. If nothing obvious is identified during the inspection, check the splitter/DC cIo.nfiguration for excessive attenuation in the return path of the cable modem.

Look for elements that cause extra attenuation to the return path signal from the cable modem outlet. If nothing obvious is identified during the inspection, check the splitter/DC

Replace the drop cable fr~e lap to the customer premises following current standards for weather protection.

Inspect every connector for water corrosion and then add water displacement grease to prevent any future migration of water inside the connector .

Install drip loops below every connection exposed to weather elements to prevent water migration into the connections.

Replace all connectors and drop system components, (splitters, directional couplers blocks,etc.)  following current standards for weather protection at every connection.

If the noise floor is less than 10 dB from the carrier peak when the input signal is removed from the spectrum analyzer, a preamplifier should be used to increase the amplitude levet of the signal into the analyzer.

If the noise fIoor drops less than 10db  when the input signal is removed from the spectrum analyzer, a preamplifier should be used to increase the amplitude level of the signal into the analyzer.

If the noise floor drops by 10 dB or more when the input signal is removed from the spectrum analyzer, a preamplifier should be used to increase the amplitude level of the signal into the analyzer.

If the noise floor is more than 10 dB from the carrier peak when the input signal is removed from the spectrum analyzer, a preamplifier should be used to increase the amplitude level of the signal into the analyzer.

Low value taps (17 dB and lower) have high isolation between ports and offer less attenuation to ingress and impulse noise coming from an Individual drop system.

Low value taps (17 dB and lower) have high isolation between ports causing cable modems and set-top boxes (STB) attached to the same tap to interfere with the other's return path transmission.

Low value taps (17 dB and lower) have less isolation between ports causing cable modems and set-top boxes (STB) to transmit at higher output levels.

Low value taps (17 db and lower) have less isolation between ports and offer less attenuation to ingress and impulse noise coming from an individual drop system.

Hum at 120 Hz or higher is caused by too much current flowing through

Hum at 120 Hz or higher is caused by the filtering of the RF signal from an AC power supply.

Hum at 120 Hz or higher is caused by induced voltage from a shielded power cable onto the center conductor of the coaxial cable.

Hum at 120 Hz or higher is caused by poor filtering of the AC signal from a DC power supply.