Service Technician
What is the output port signal power level in dBmV at 50 MHz on the high output port of a three-way unbalanced splitter when: (1) the input signal level is 39 dBmV at 50 MHz and 46 dBmV at 750 MHz; and (2) the high output port insertion loss is 4.1 dB at 50 MHz and 5.2 dB at 750 MHz?
34.9 dBmV.
What is the voltage into amplifier B, the second amplifier in cascade, under the following conditions? Each amplifier draws 1.5 amps of current. The output of the 60 VAC power supply is inserted 1,188 feet from the input of amplifier A. On the output of amplifier A is 1,320 feet of cable feeding amplifier B. The cables have the same resistance of 1.1 ohm per 1,000 feet.
53.9 VAC.
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 cable's loop resistance is 1.07 Ohms/1,000 feet; (3) the power supply output voltage is 60 VAC; and (4) the total current requirement is 11.4 amps?
54.92
Bit error rate (BER) is one of the measurements a technician uses to determine how well the network is operating. What is an acceptable post-BER at the end of the drop?
<1.0E-9.
What does a digital multimeter (DMM) measure?
A digital multimeter (or VOM) measures AC and DC voltages, resistance for continuity checks, and current.
What is an air-core transformer?
An air-core transformer is a transformer that uses air or a non-magnetic material as the core material.
The square wave and the sawtooth wave AC waveforms
Seem to decrease "instantly" from a maximum positive value to a maximum negative value of voltage or current.
What happens when a capacitor is fully charged?
The current reverses directions and flows back through the source.
What does the configuration of the directional coupler faceplate and housing enable?
The housing can be installed in any orientation, regardless of the direction of signal flow.
When are the outputs of two AC generators in-phase?
The outputs of two AC generators are in-phase if they achieve their maximum magnitude at the same time.
What is the peak value of an AC waveform?
The peak value of an AC waveform is another name for the amplitude of the waveform. It is defined as the vertical distance between the most positive or most negative level on the waveform and the horizontal axis.
What is the proper troubleshooting technique?
unknown signal status in half, verify the signal condition, and repeat (if necessary) until the source of the problem is found.
Define "flux lines."
"Flux lines" are magnetic lines of force running longitudinally from the north pole to the south pole of a magnet.
What are five important components of an amplifier station?
Five important amplifier station components are: (1) input and output diplex filters that separate and combine the forward and return paths within the amplifier; (2) forward and return plug-in pads and equalizers for controlling the input signal levels; (3) an RF amplifier module; (4) an integrated or stand-alone DC power supply with DC current fusing; and (5) AC power direction control.
The Occupational & Safety Administration (OSHA) requires that operators with more than 11 employees keep accurate records of job accidents. How long must a qualifying company keep a record of an accident that required medic treatment for an employee?
Five years.
Which of the following is true about the resonant frequency?
It is the frequency at which the inductive reactance equals the capacitive reactance in a circuit with an inductor and a capacitor.
Which of the following is true about capacitive reactance?
It is the opposition to current flow in an AC circuit caused by a capacitor.
Reverse test alignment is used to adjust which of the following signal types?
Test signals from the field to the headend.
Capacitors
That are fully charged act like an open circuit to the source.
Alternating current is a current
That changes direction (or alternates) in the conductor each time the potential difference applied to the ends of the conductor changes (or alternates) its polarity.
In resistive AC circuits,
The AC power waveform has two positive half-cycles and two positive peaks.
Where does the AC voltage appear in an AC generator consisting of a loop of wire rotated between the poles of a magnet?
The AC voltage appears across the gap between the ends of the loop in an AC generator consisting of a loop of wire rotated between the poles of a magnet.
Which of the following is a requirement in the process for measuring leakage using a dipole antenna, as required by the FCC?
The antenna must be placed 3 meters from the system components and 3 meters from the ground.
Which of the following generally has the highest fixed capacitance values?
Electrolytic capacitors.
Which of the following is better at making an extrinsic semiconductor a conductor?
Electrons and holes are equally important.
When compared to unjacketed cable, jacketed hardline coaxial cable
Has additional corrosion protection, more cable support, and improved handling characteristics.
An RF/AC bypass tap
Has the added feature of being able to maintain RF signal and AC voltage continuity during faceplate removal.
Which of the following describes a A low-pass filter
It is used when upper frequencies are not required in a circuit.
Which of the following are referred to as trimmer capacitors?
Variable mica capacitors.
The type of time domain reflectometer (TDR) you use is affected by cost, personal preference, and technical specifications. If your job required that the TDR be able to generate cable signature displays, which TDR would you use?
Waveform TDR.
Which of the following is the distance occupied by 1 hertz (Hz)?
Wavelength
What type of relationship exists between wavelength and frequency?
Wavelength is inversely proportional to frequency.
What are the three main components of a typical standby power supply?
he three main components of a standby power supply are: (1) a ferroresonant transformer that supplies the output voltage; (2) a set of batteries acting as a backup power source; and (3) an AC inverter that converts the DC battery backup power to a 60 or 90 VAC output.
A distribution amplifier requires a specific power input to function. How much DC power is provided by the B+ regulated DC voltage power supply?
+24 volts DC.
What is the interfering RF signal level on output port 2 when: (1) the input leg is terminated; (2) the internal isolation is 32 dB; and (3) there is an applied signal of 7 dBmV on output port 2?
-25 dBmV
What is the time period of one cycle or wavelength of an AC waveform when the frequency of the waveform is 50 Hz?
0.0200 seconds
What is the approximate forward voltage drop of a silicon diode?
0.7 volt.
Velocity of propagation (VOP) is the speed of the RF signals traveling in a coaxial cable relative to the speed of light. What is the range of VOP factors for broadband coaxial cable?
0.78 to 0.93.
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.
What is the power consumed by the load when: (1) the voltage across the load is 7.5 volts; (2) the current flowing through the circuit is 0.25 amperes; and (3) the resistance of the load is 30 ohms?
1.88 watts
It is critical that cable signals don't interfere with communication between air craft and air traffic controllers. What is one of the aeronautical bands of concern to cable operators?
108-137 MHz
If your leakage detector indicates there is a leak and displays a reading of 14 microvolts per meter (uV/m) when you are 80 feet from a possible leak source, what is the approximate calculated level of the leak from 10 feet?
112 µV/m.
What is the value of the current when: (1) the effective voltage is 120 volts; (2) the resistance of the source is 3 ohms; (3) the resistance of the conductors is 2 ohms; and (4) the resistance of the load is 5 ohms?
12.00 amperes
What is the total inductive reactance of a circuit with three inductors in series when: (1) the inductors have individual inductances of 15 mh, 20 mh, and 25 mh; and (2) the AC power source is 50 Hz?
18.84 ohms.
A two-way splitter that is 600 feet away from an amplifier has what outputs when given the following: (1) the output of the amplifier is 25 dBmV at 50 MHz and 31 dBmV at 550 Mhz; (2) the 600 feet of cable loses 1.98 dB at 50 MHz and loses 6.48 dB at 550 MHhz; and (3) the two way splitter loses 3.8 dB at 50 MHz and loses 4.4 dB at 550 MHz?
19.22 dBmV at 50 MHz and 20.12 dBmV at 550 MHz.
To transmit AC power efficiently, what power line voltage-current combination would deliver the same amount of power as 10 amps and 10,000 volts, but with the least heat loss?
2 amps and 50,000 volts.
What is the total capacitive reactance of a circuit with two capacitors in series when: (1) the capacitors have individual capacitive reactances of 0.8 ohms and 1.6 ohms; (2) the AC power source is 1 MHz; and (3) the AC power source is 60 volts?
2.40 ohms.
What is the proper way to express a signal voltage of 10 mV in cable TV terms?
20log(10mV/1mV) = 20 dBmV.
What is the two-way splitter's output port signal level @ 50 MHz and 550 MHz when: (1) the amplifier output signal level is 33 dBmV at 550 MHz and 27 dBmV at 50 MHz; (2) there is 500 feet of 0.750 trunk cable between the amplifier and two-way splitter with 0.37 dB loss/100 feet at 50 MHz and 1.24 dB loss/100 feet at 550 MHz; and (3) the splitter's insertion loss is 3.70 dB at 50 MHz and 4.35 dB at 550 MHz?
21.45 dBmV at 50 MHz and 22.45 dBmV at 550 MHz.
What is the total cable loss of a 1,600-foot length of 0.750 cable at 600 MHz and 120 degree F, if at 68 degree F and 600 MHz the cable attenuation rate is 1.31 dB/100 feet? (Be sure to factor in the higher temperature.)
22.05 dB.
What is the power consumed by coaxial cable loop resistance when: (1) the current of the coaxial cable circuit is 5 amperes; (2) the loop resistance of the coaxial cable is .9345 ohms; and (3) the AC power source has an effective voltage of 60 volts?
23.36 Watts
What is the three-way splitter's port signal power level on the high output port when: (1) the input signal level is 27.50 dBmV at 50 MHz and 29.75 dBmV at 550 MHz; (2) the splitter insertion loss through output port A is 6.90 dB at 50 MHz and 7.75 dB at 550 MHz; (3) the splitter insertion loss through output port B is 6.90 dB at 50 MHz and 7.75 dB at 550 MHz; and (4) the splitter insertion loss through output port C is 3.65 dB at 50 MHz and 4.45 dB at 550 MHz?
23.65 dBmV at 50 MHz and 25.30 dBmV at 550 MHz
The output port RF signal level is ______________ dBmV at 50 MHz and the tap port signal level is _______________ dBmV at 50 MHz for a two-way feed- through tap when: (1) the input port signal level is 30.5 dBmV at 50; (2) the insertion loss is 3.3 dB at 50 MHz; and (3) the tap loss is 7.6 dB at 50 MHz.
27.2 and 22.9
What is the wavelength of one cycle of an AC waveform when: (1) the frequency of the waveform is 80 Hz; (2) the speed of light is 300,000 kilometers per second; and (3) the waveform has an amplitude of 5 volts?
3,750
Modulation error ratio (MER) is an indicator of digital modulation signal quality. For error-free reception and adequate margin, what should be the minimum MER reading for a 256-QAM (quadrature amplitude modulation) signal?Modulation error ratio (MER) is an indicator of digital modulation signal quality. For error-free reception and adequate margin, what should be the minimum MER reading for a 256-QAM (quadrature amplitude modulation) signal?
32 dB.
What is the downstream output port signal level for a directional coupler when: (1) the input signal level is 35.0 dBmV; (2) the output port insertion loss value is 1.4 dB?
33.6 dBmV.
How many electrons does Silicon have in its outer shell?
4
What is the return signal pass band frequency used in most of North America?
5-42 MHz
Calculate the capacitive reactance of a power inserter's feed-through capacitor when: (1) the frequency is 50 MHz; and (2) the capacitance value is 1,000 pF?
5.30 Ohms.
When you use a digital signal analyzer to examine a digital signal, one of the values you should check is the symbol rate. What should the symbol rate setting be for a 256-QAM signal specified by the International Telecommunication Union (ITU) in ITU-T J.83 Annex B?
5.360537 megasymbols per second (MS/s).
What would be the voltage drop across a cable 1,250 feet away from a 60 VAC power supply, if the cable is .625-inch with a resistance of 1.1 ohm per 1,000 feet, conducting 4 amperes?
5.5 VAC.
How much intermodulation distortion degradation is created when two line extender amplifiers with similar distortion characteristics are in cascade?
6 dB.
Which of the following directional coupler values will exhibit the highest output insertion loss?
7 dB
What is the average value of an AC waveform that has an effective value of 8 volts?
7.2 volts.
What is the peak-to-peak value of an AC waveform when: (1) the frequency is 60 Hz; (2) the maximum negative value of the waveform is -4 volts; and (3) the effective value of the waveform is 2.83 volts?
8.0 volts peak-to-peak.
What is the tap port RF signal level at 550 MHz for a four-way terminating tap when: (1) the preceding tap's output port signal level is 25.0 dBmV at 550 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 550 MHz?
8.8 dBmV.
What does a time domain reflectometer (TDR) measure?
A TDR measures the presence of and distance to cable faults.
In a conventional axial leaded diode (one with a cylindrical body and leads coming out either end), the cathode is usually denoted by
A band around the body of the diode.
In a line extender, which component is used to correct positive tilt?
A cable simulator.
Which tool do you use to measure the input current on the input wiring?
A clamp-on ammeter.
What is the purpose of a coaxial express cable in an HFC distribution system?
A coaxial express cable allows a particular optical node to reach farther out in the distribution system.
What does a combination SLM/leakage detector measure?
A combination SLM/leakage detector incorporates the features of both an SLM and a signal leakage detector.
What is one type of device used for output surge protection on a ferroresonant transformer?
A crowbar circuit.
Define the term cycle.
A cycle is defined as one complete rotation of an armature in a generator, one complete sine wave, two alternations of any AC waveform, or 360° of angular motion.
_____________________ is a short length of fiber that serves as an amplifier in fiber-optic networks, allowing light signals to travel farther while retaining signal strength.
A distributed fiber amplifier (DFA).
Does a fluctuating DC waveform change in polarity and/or in magnitude?
A fluctuating DC waveform does not change in polarity, but it does change in magnitude.
What is a henry (h)?
A henry is the amount of inductance a conductor or inductor has if the current flowing through it changes at the rate of 1 ampere per second and generates a cemf of 1 volt.
What is a high-pass filter?
A high-pass filter is a type of bandpass filter that passes all frequencies above a specific frequency (e.g., 50 MHz), and eliminates common path distortions, impulse noise in the return spectrum, and any other frequencies that fall below that specific frequency.
How is a rate of 4,500 cycles per minute expressed in cycles per second?
A rate of 4,500 cycles per minute is equal to 75 cycles per second. To calculate: 4,500 ⁄ 60 = 75 cps.
As you prepare to set up 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 refractive star coupler.
What does a signal leakage detector measure?
A signal leakage detector is an RF receiver with an installed input antenna that measures broadband cable signals leaking from the system within FCC assigned aeronautical frequency bands.
What does the output waveform of a ferroresonant transformer most closely resemble at maximum load?
A sine wave.
What is a slip ring in an AC generator consisting of a loop of wire rotated between the poles of a magnet?
A slip ring is a smooth circular band of conducting material connected to one end of the loop, in an AC generator consisting of a loop of wire rotated between the poles of a magnet.
A system design map is used to analyze system for the device common to the customers so far affected before traveling to make additional signal status checks.
A system design map is used to analyze system for the device common to the customers so far affected before traveling to make additional signal status checks.
How can a distribution system design map aid the troubleshooting process, after gathering as much information as possible about the extent of the affected area?
A system design map is used to analyze system for the device common to the customers so far affected before traveling to make additional signal status checks.
Which testing device is the best to use to measure cable faults?
A time domain reflectometer (TDR).
What is a transformer?
A transformer is two circuits combined using inductors in close proximity to each other for the express purpose of energy transfer.
Where does the feeder system forward path start and end in a tree-and-branch design?
A tree-and-branch feeder system forward path starts at the output of the bridger amplifier module in the trunk/bridger amplifier station and ends at the tap port of an RF tap.
Which tool do you use to accurately measure the output voltage of a ferroresonant power supply?
A true RMS (root mean square) DMM.
Convert the following values to peak-to-peak values:
A. A peak voltage value, Epk = 5.5 volts B. An average voltage value, Eav = 15.9 volts C. An effective current value, IEFF = 1.061 amperes An RMS current value, IRMS = 2.123 amperes The converted peak-to-peak values are: (A) 11 volts; (B) 50 volts; (C) 3 amperes; and (D) 6 amperes. To calculate: (A) 2 × 5.5 volts = 11 volts peak-to-peak; (B) 2 × (15.9 volts/0.636) = 50 volts, or 2 × 1.57 × 15.9 = 50 volts peak-to-peak; (C) 2 × (1.061 amperes/0.707) = 3 amperes peak‑to-peak, or 2 × 1.414 × 1.061 amperes = 3 amperes peak-to- peak; and (D) 2 × 1.414 × 2.123 amperes = 6 amperes peak-to-peak.
A hardline RF splitter's
AC characteristics determine the maximum amount of current the splitter can pass and how much hum is introduced to the RF signal.
Define an AC power source.
AC generator" is the term used more commonly than "alternator" to describe an AC power source.
What is converted by a transformer in an AC power transmission system?
AC power developed from one voltage-current combination is converted to a different voltage-current combination by a transformer in an AC power transmission system.
How is AC power transmitted in an RF tap?
AC power passes bidirectionally through the tap, but is prevented from passing through to the tap ports except by design in power-distributing taps.
What does a signal level meter (SLM) measure?
An SLM measures individual analog video and audio, and digital carrier levels.
Which of the following devices is an active device?
An addressable tap.
Automatic level control (ALC) and thermal control are two methods used to maintain consistent signal levels in line extenders. Which type of application requires the use of one of these methods?
Aerial installation
Where are air-core transformers typically used?
Air-core transformers are typically used in radio-frequency electronic applications.
Which of the three values are assumed to be effective values, unless specified otherwise, in the power equation P = EI for AC resistive circuits?
All the three values of power, voltage, and current are assumed to be effective values, unless specified otherwise, in the power equation P = EI for AC resistive circuits.
Many cable companies require which type of leaks to be fixed?
All types of leaks must be fixed.
When does alternating current change direction in the conductor?
Alternating current changes direction (or alternates) in the conductor each time the potential difference applied to the ends of the conductor changes (or alternates) its polarity.
All true AC waveforms
Always are symmetrical about the horizontal axis.
What does an AC generator produce using magnetism and mechanical motion?
An AC generator produces AC voltage using magnetism and mechanical motion.
Define an AC waveform.
An AC waveform is a continuous plot of the magnitude of a current or voltage with respect to some quantity, usually time.
Shorts in the coaxial cable and excessive amounts of current can damage the distribution amplifier. Several devices can be used to protect the distribution amplifier from these problems. Which device shorts to ground when an overvoltage situation occurs?
An FTEC (Fast Transfer Electronic Crowbar).
Where does the distribution system forward path begin and end in an HFC design?
An HFC distribution system forward path begins at the output of an RF amplifier located in the optical node and ends at the tap port of an RF tap.
There are several passive components in a distribution amplifier. Each component changes the signal in a different way. Which component reduces the signal equally at all frequencies?
An attenuator pad.
Which type of distribution amplifier gain control maintains the amplifier's RF output at a set level if the input levels to the amplifier change (within design tolerances)?
An automatic gain control (AGC).
You have a cable modem analyzer and you want to replace the cable modem to determine whether the modem is bad. How should the modem analyzer be connected to replace the modem?
An ethernet cable is connected from the cable modem analyzer to the customer's computer and the RF drop input cable is connected to the cable modem analyzer
What is the function of an interdiction unit?
An interdiction unit controls the level of service to the drop ports it contains.
If we have chosen our dopants correctly to generate light energy of the correct wavelength, what must be added to a light emitting diode to make it a Fabry Perot (F-P) laser?
An interferometer, consisting of a mirror on one end of the laser diode and a partially- reflecting mirror on the other end.
What is an iron-core transformer?
An iron-core transformer is a transformer that uses high permeability material such as iron or ferrite as the core material.
In a standby ferroresonant power supply, what device keeps the battery- powered AC power from feeding back to the utility?
An isolation relay.
A time domain reflectometer (TDR) will measure through coaxial cable and many types of cable devices. Which type of device will a TDR not measure through?
An unpowered active device.
Which of the following FCC required information must a cable system keep on file for two years?
Annual CLI calculations, regular (quarterly) monitoring programs, and a list of all channels used in the aeronautical bands.
What are two uses of PIN diodes?
As current-variable RF resistors and fast RF switches.
What part of an AC waveform corresponds to a negative polarity for the voltage or current?
Any part of an AC waveform below the horizontal axis usually corresponds to a negative polarity for the voltage or current.
Inductors
Are rated in units of henrys.
Skin-effect losses
Are reduced by using multiple-strand conductors instead of a single, large diameter conductor.
Hardline three-way RF splitters
Are unbalanced when they have two 'low-level' output ports with more signal loss and the one 'high-level' output port with less signal loss.
What happens as a conductor is passed through a magnetic field?
As a conductor is passed through a magnetic field, the magnetic field around each free electron interacts with the flux lines of the large magnetic field as the conductor cuts through them, and electromotive force (emf) is exerted on each electron.
One application for the varactor diode is
As a reference frequency standard that locks 10 MHz oscillator to a precise frequency.
When you service a line extender, you measure AC and DC voltage levels. Where do you measure the AC ripple?
At the B+ test point.
You are performing periodic maintenance on a standby ferroresonant power supply. Where should you measure the output current?
At the stinger wire.
Performing preventive maintenance will help the cable operator avoid system outages. How should the priority for preventive maintenance be determined?
Based on its importance to the system operations. Areas that affect the entire system should be checked most frequently.
How is skin effect similar to eddy currents?
Both skin effect and eddy currents are caused by the presence of AC voltages in the conductors, and both are frequency dependent.
What factors define the extent of a power realm?
Cable resistance, combined amplifier load requirements, individual amplifier voltage minimums, and limits on AC current define the extent of power realms.
A fluctuating DC waveform
Can be identical to an AC waveform, except that the fluctuating DC waveform never changes polarity.
Eddy currents
Can cause a loss of power in an AC circuit.
Which of the following was a popular circuit in the vacuum tube era?
Center-tapped circuit.
On cable system design maps, standard symbols include a
Circle for a two-way tap, a square for a four-way tap, and a hexagon for an eight-way tap.
What are two other names for inductor?
Coil and choke are two other names for inductor
As you work with distribution amplifiers on the cable system, you must be aware that what you do can affect the various types of signal distortions. What type of distortion is defined as "an interfering beat whose frequency is ±.75 MHz or ±1.25 MHz from the video carrier frequency"?
Composite second order (CSO).
The total capacitance of individual capacitors
Connected in series is always smaller than the smallest capacitor value.
In a power transmission circuit, the transformer located near the user's home, Typically
Converts the high voltage, low current combination carried on the transmission lines to a low voltage, high current combination for residential use.
A distribution amplifier is housed in a die-cast aluminum housing. What is another item that can be mounted to the housing cover that connects to the distribution amplifier?
DC power supply.
Inductance in an inductor
Decreases when the number of turns around the core are decreased or when there is an increase in the spacing between the turns around the core.
The eddy-current losses in the conductors of an AC circuit are
Dependent on the frequency of the current flowing through the conductors.
In order to form a junction diode, you put p-type and n-type semiconductor materials abutting each other. When you do, then some electrons cross the junction, as do some holes. The region occupied by the holes and semiconductors that have crossed the junction is referred to as the __________ region.
Depletion region.
The polarity of a DC waveform
Does not change.
If a large signal leak is found in the aerial plant, what is a good first step in locating the leak?
Drive around until an absolute peak is found.
What are the basic types of electronic circuit grounds we might encounter in a modern electronic circuit?
Earth ground, chassis ground, and signal ground.
How are eddy currents created?
Eddy currents are created in the conductors of an AC circuit by the changing magnetic field around the conductor as alternating current flows through the conductor. The changing magnetic field induces voltages inside the conductor, and these voltages generate small currents in the conductor.
What apparent effect do eddy currents have on the power consumed in conductors in AC circuits?
Eddy currents cause eddy current loss, which combines with the ohmic resistance of the conductors to increase the power consumed in the conductors
What is the effect of eddy currents on the power consumed in the circuit?
Eddy currents dissipate some of the power present in the circuit in the form of heat.
What does eliminating a discovered signal leak accomplish?
Eliminating a discovered leak averts a potential outage or trouble call.
Which is inductive reactance?
Equal to 2πƒL; π (pi) is 3.14, f is the frequency of the applied AC source voltage in hertz, and L is the circuit inductance in henrys.
One time constant (t)
Equals the time required to charge a capacitor to 63% of its fully charged voltage.
Why does it take a few minutes for a cable modem analyzer to become functional once connected to the network?
Every time the cable modem analyzer function is enabled, the instrument's internal modem must be provisioned with the cable modem termination system (CMTS).
It is the technicians' responsibility to inspect the equipment that they use. How Often should technicians inspect hand tools and ladders?
Every time they are used.
As cable companies have expanded 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).
List three mechanical forces used to turn the armature of AC generators in large-scale AC power production.
Flowing water, burning coal to produce steam, and using a nuclear reactor to produce steam are three mechanical forces used to turn the armature of AC generators in large-scale AC power production.
Which of the following statements is true?
For each power inserter, the system design must ensure that (1) the current required by any one RF/AC port does not exceed that ports power-passing specification and the current required by both RF/AC ports does not exceed the AC input port power-passing specification
Name four common true AC waveforms.
Four common true AC waveforms are the sine wave, the square wave, the sawtooth wave, and the quasi-square wave.
Define frequency.
Frequency is defined as the number of cycles that an armature turns, or the number of cycles of an AC waveform that occur, in one second.
Which of the following items is used to help protect power inserters from lightning damage?
Gas discharge pellets.
Air-core transformers
Get their name from the material used as the core of the transformer.
What is one of the basic principles of resistance reflected in the familiar practices of grounding and bonding?
Grounding and bonding practices reflect the basic principle that electricity always follows the path of least resistance.
To connect two line passive or active devices together without jumper cables, use a(an)
Housing-to-housing adapter.
What information about the digital carrier can be learned by accessing the adaptive equalizer function of the digital signal analyzer?
How much the adaptive equalizer has to compensate for linear distortions of the digital carrier
If the primary and secondary coil voltages are equal in an ideal transformer, what is the relationship of the primary and secondary coil currents?
If the primary and secondary coil voltages are equal in an ideal transformer, the primary and secondary coil currents must be equal also.
How does increasing the number of turns of the winding around the core of the inductor affect the inductance?
Increasing the number of turns of the winding around the core of the inductor increases the inductance.
Flooding compound should be cleaned from the cable
Immediately after removing the jacket and/or armoring.
Why does a conductor with no flowing current have no magnetic field around it?
In a conductor with no flowing current, free electrons move randomly and their magnetic fields cancel each other, resulting in a total magnetic field value of zero around the conductor.
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 unit of frequency replaced cps in the 1960s?
In the 1960s, cps was replaced by hertz (Hz), which is equal to one cycle per second.
Technician safety is important to the cable operator, and an important part of OSHA guidelines. Where should personal protective equipment (PPE) for field employees be stored?
In the truck.
Coherent interference causes the constellation display to look like a series of small donuts. What is one cause of coherent interference?
In-channel ingress.
What two properties of an AC circuit must be negligible compared to the resistance of the circuit for the circuit to be considered completely resistive?
Inductance and capacitance in an AC circuit must be negligible compared to the resistance of the circuit to consider the circuit completely resistive.
What is inductance?
Inductance is the property of an electrical circuit or conductor that tends to resist changes in the current flowing through the circuit or conductor.
Define induction.
Induction, otherwise known as electromagnetic induction, is the production of anelectromotive force, or emf, in a conductor by changes in the magnetic field surrounding the conductor.
As frequency increases through a splitter,
Insertion loss increases.
Why are insulating-core inductors also called air-core inductors?
Insulating-core inductors also called air-core inductors because the insulating core is only for supporting the coiled conductor, and the insulating core has no magnetic properties.
Which of the following is the least important characteristic of an intrinsic semiconductor?
Intrinsic semiconductors are typically made of silicon material.
Where are iron-core transformers typically used?
Iron-core transformers are typically used in electric power distribution systems.
When the primary-to-secondary turns ratio in a transformer
Is 1:2 or 1/2, the secondary coil voltage is two times larger than the primary coil voltage.
The average value
Is 3.18 volts for a waveform with a peak value of 5 volts.
A farad
Is a unit of capacitance.
The peak value of a waveform
Is another name for the amplitude of the waveform.
The output voltage waveform generated by an AC generator during one complete rotation of the generator's armature
Is called a sine wave.
Through magnetism and mechanical motion.
Is directly proportional to the amount of resistance present and to the square of the amount of current.
One cycle
Is equal to one complete rotation of the armature of an AC generator.
The total inductance of an AC circuit
Is equal to the sum of all the individual inductances when the circuit's inductors are connected in series.
A phase angle
Is the amount of time, in degrees, that separates two waveforms.
The terminating tap
Is the last tap installed at the end of the feeder cable run.
Induction
Is the production of an electromotive force (emf) in a conductor by changes in the magnetic field around the conductor.
The trunk and feeder coaxial cable's DC loop resistance
Is the sum of the center conductor resistance and the aluminum sheath resistance.
The center conductor of trunk and feeder coaxial cable
Is typically bonded to the dielectric with a polymer adhesive coating or center conductor treatment to inhibit moisture migration and corrosion.
The intrinsic region in the middle of a PIN diode is useful because
It allows the RF resistance of the diode to be controlled by the DC current in the diode.
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.
Which of the following describes counter electromotive force (cemf)?
It determines the amount of current flowing through the circuit from the AC source, in an inductive AC circuit.
Which characterizes a feed-through tap?
It 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.
Which statement about the total inductive reactance of a circuit with two inductors in parallel is true?
It is always smaller than the lowest individual inductive reactance value among the inductors in the circuit.
When light strikes a medium at an angle less than the critical angle, what happens to the light?
It is reflected.
Which of the following is true about the bandwidth of a resonant circuit?
It is the band of frequencies between the 70.7% points of the voltage curve for parallel resonant circuits or the current curve for series resonant circuits.
What are the three main metric prefixes associated with frequency, and what do they represent?
Kilo, mega, and giga are the three main metric prefixes associated with frequency. Kilo = 1,000, mega = 1,000,000, and giga = 1,000,000,000.
Why are large diameter wires and silver wires not commonly used to reduce resistance in power transmission circuits?
Large diameter wires and silver wires are not commonly used to reduce resistance in power transmission circuits because they cost much more than thinner, copper wires.
Line extenders can be powered from the cable system or from a 120 VAC source. Which of the following statements about line extender power sources is true?
Line extenders powered by the cable system can pass current to other devices.
What tasks are involved in maintaining physical plant integrity within the distribution system?
Maintaining physical plant integrity involves: (1) checking and tightening loose connectors, housing enclosures, and tap face plates; (2) lubricating pedestal and power supply padlocks periodically during normal access; and (3) securing and documenting any broken lashing wire to prevent further deterioration.
When you are installing or troubleshooting a distribution amplifier, what should you do to make sure that there is a flat frequency response coming from the amplifier?
Make sure the cover plates are tightened.
The hardline RF splitter mechanical component that
Makes a mechanical and an electrical connection between the splitter and the coaxial cable's pin connector is the seizure screw.
Complying with Occupational Safety & Health Administration (OSHA) standards is which of the following?
Mandatory
The basic power relationship "p(t) = e(t)i(t)"
Means the power at a specific instant equals the voltage at that same instant times the current at that instant.
You want to check the blind spot of the coaxial cable for cable faults. Which of the following actions would be correct?
Measure the cable from the opposite end.
What is done to reduce skin-effect losses in AC power conductors?
Multiple-strand conductors, instead of large, single-strand conductors, are used in AC power cables to reduce the skin losses.
The standard impedance in trunk and feeder coaxial cable
Must be maintained to prevent picture distortions, such as ghosting and smearing.
What is mutual inductance?
Mutual inductance is the property possessed by two inductors so positioned that the changing magnetic field lines around one of the inductors encircle, or link, the turns of the other inductor and induce an emf, or voltage, in that inductor.
The time domain reflectometer (TDR) cannot find a fault located in the blind spot or dead zone of the cable. Where is the blind spot in a cable located?
Near the output of the TDR.
When adjusting or selecting the elements of a dipole antenna for measuring signal leakage, what is the approximate length of each element relative to the wavelength of the signal being measured?
One-quarter wavelength.
How many cable faults can a digital TDR (time domain reflectometer) detect at one time?
One.
How many amps combined with 1,000 volts equal the power produced by 10 amps combined with 100 volts?
One amp combined with 1,000 volts equal the power produced by 10 amps combined with 100 volts.
What is the wavelength in miles and in meters of one cycle of an AC waveform whose frequency is 1,000 Hz?
One cycle of an AC waveform whose frequency is 1,000 Hz has a wavelength of 186 miles or 300,000 meters. To calculate in miles: 186,000 miles per second/1,000 Hz = 186 miles. To calculate in meters; 300,000,000 meters per second/1,000 Hz = 300,000 meters.
What is the period of one cycle of a waveform with a frequency of 1,000 Hz?
One cycle of an AC waveform with a frequency of 1,000 Hz has a period of 0.001 seconds. To calculate: 1 cycle/1,000 Hz = 0.001 seconds.
After wrench-tightening a two-piece pin connector's front nut to an amplifier, two adjustable wrenches are required because
One wrench keeps the front nut from rotating while the other wrench tightens the back nut against the front nut.
If you needed to couple a control signal from one circuit to another, while keeping the ground connections isolated in the two circuits, what component would you use?
Opto-isolator.
How often are outages caused by equipment failures?
Outages caused by equipment failures generally occur less frequently than other outage categories.
Define the term period.
Period is the amount of time it takes to complete one cycle of an AC waveform.
Define phase difference.
Phase difference is the amount of time in degrees separating two waveforms.
What information is provided from a Ping command?
Ping is used to measure the round-trip time for a ping packet to travel over the network from the cable modem to the cable modem termination system (CMTS), or other server, and back.
As the RF signal travels on the coaxial cable, one portion of the signal may be attenuated more than the others. What term is used to describe a situation where cable attenuation is low, causing signal levels to remain greater at the higher frequencies than at the lower frequencies?
Positive tilt.
What are six performance checks involved in maintaining power supplies?
Power supply performance checks include: (1) AC input voltage; (2) AC output voltage; (3) output current (amperage) draw; (4) individual battery voltages; (5) charging (float) voltages; and (6) standby switching capability.
After a foam dielectric cable is properly cored and stripped, the cable's center conductor should be
Prepared with a pyramid-shaped cut to the tip.
What are the three most common components of an atom, and where are they located in the atom?
Protons and neutrons are located in the nucleus of the atom, and electrons are located in orbit around the nucleus.
How and why does pulling the iron core out of the windings affect the inductance of a variable iron-core inductor?
Pulling the iron core out of the windings reduces the inductance of a variable iron-core inductor, because fewer of the inductor windings have their flux lines concentrated by the focusing effect of the magnetic iron core.
A henry is
Quite a large amount of inductance, so inductance in AC circuits is usually expressed as a smaller value; in fractions of one henry.
Which type of signal impairment causes the constellation symbol points to spread out toward the grid lines?
Random noise.
Attenuation in trunk and feeder coaxial cable
Reduces the amplitude of transmitted signals.
The impedance of coaxial cable or a device is made up of the combined effects of which three electrical properties
Resistance, inductance, and capacitance.
In use, a photodiode is normally
Reverse biased.
To weatherproof a pin connector with heat shrink, the tubing
Should be cut straight and clean if it needs to be trimmed, because jagged edges might split the tubing when it is heated.
Unity gain is achieved when the signal strength along a cable is maintained at a specific level by the amplifiers. If the gain generated by an amplifier is too high, what will be the most likely result?
Signal distortion.
What effect does skin effect have on the power consumed in the conductor?
Skin effect increases the power consumed in the conductors by increasing the resistance of the conductor.
What causes skin effect?
Skin effect is caused by the voltages induced in the core of the conductor by the changing magnetic field around the conductor causing the electrons flowing in the conductor to be packed closer together nearer the surface than at the core, or center, of the conductor, as they flow through the conductor.
What is skin effect?
Skin effect is the concentration of flowing current near the surface of the conductor.
Which of the following is created by an amplifier module?
Slope.
To properly prepare hardline coaxial cable for connectorization
Some combination coring/stripping tools have an optional stop that automatically sets the coring/stripping depth for the proper center conductor length.
What is the role of splitters and directional couplers in the forward and return paths?
Splitters and directional couplers divide and route the forward RF signal transmission throughout the distribution system, and combine return-path signals arriving from separate feeder runs.
Certain ways of using a time domain reflectometer (TDR) are considered best practices, and are most likely to give you the most accurate results in the shortest amount of time. If you want to check a coaxial cable for faults and measure its length using the best practice, how would you set the pulse width?
Start with the shortest pulse width.
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.
Current exists in a diode when which condition obtains?
The anode is more positive than the cathode.
What is the relationship of the primary coil current to the secondary coil current in an out-of-phase transformer?
The amount of current flowing in the primary coil is directly proportional to the amount of current flowing in the secondary coil in an out-of-phase transformer.
What is the relationship between the amount of inductance and the permeability of the inductor core?
The amount of inductance is directly proportional to the permeability of the inductor core.
What is the relationship between the amount of inductance and the length of the inductor, or coil, if the number of turns is held constant?
The amount of inductance produced by an inductor is inversely proportional to the length of the inductor, or coil, if the number of turns is held constant.
What is the decrease in the amount of power wasted as heat when the current is cut in half in a transmission line?
The amount of power wasted as heat is cut to one-fourth of the original amount of heat loss when the current is cut in half in a transmission line.
What is the relationship between eddy currents loss and the frequency of the current in an AC circuit?
The amount of the eddy currents loss due to eddy currents in the conductors of an AC circuit is directly proportional to the frequency of the current flowing through the conductors.
Define amplitude.
The amplitude of any AC waveform is defined as the most positive or most negative level achieved by the waveform.
How do frequency and cable size affect the attenuation of a broadband signal?
The attenuation of a broadband signal increases with higher frequencies and decreases with larger cable size.
What is the average value of one complete cycle of a sine wave whose peak voltage value is +5 volts?
The average value of one complete cycle of any AC waveform is zero because the symmetry of AC waveforms causes the sum of the positive and negative average values to equal zero.
When troubleshooting signal leakage in the drop system, what is indicated if all signs of signal leakage disappear when the ground block is disconnected and terminated on the side connected to the customer premises?
The backward route from the ground block to the tap can be eliminated as a source of leakage.
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?
The bonding Wire
What are the characteristics that determine the amount of inductance for an inductor?
The characteristics determining the amount of inductance for an inductor are: (1) the number of turns in the inductor winding; (2) the spacing between the turns or the actual length of the inductor; (3) the cross-sectional area of the core; and (4) the permeability of the core.
What is the circuit symbol for an inductor?
The circuit symbol for an inductor is a coil symbol.
Which of the following best describes demand maintenance procedures with regard to signal leakage?
The demand maintenance procedures can improve the CLI measurement results by identifying and correcting the largest leaks first.
Which of the following statements is true?
The dielectric supports the center conductor inside the aluminum sheath while providing an insulating material between the two conductors.
The return loss in trunk and feeder coaxial cable is
The difference in dB between the signal power applied to a terminated cable and the reflected signal power.
What is represented by the distance between any point on an AC waveform and the horizontal axis?
The distance between any point on an AC waveform and the horizontal axis corresponds to the magnitude of the voltage or current with respect to that instant of time.
What is the distinction between a line extender amplifier and a distribution amplifier?
The distinction is a line extender, which has a single output port and a distribution amplifier, or minibridger, which has multiple output ports (typically three ports; a through-port and two auxiliary output ports).
Why can the effect of electrical inertia be quite significant and present all the time in an AC circuit?
The effect of electrical inertia can be quite significant and present all the time in an AC circuit because the alternating current is continually changing in amplitude and direction.
Why is the effect of electrical inertia very small in a DC circuit?
The effect of electrical inertia very small in a DC circuit because the delay between the application of the DC voltage to the circuit and the time that the direct current reaches its maximum amplitude is very small, and because the inertia is only present when the voltage is applied or removed.
What is the effective value of AC?
The effective value of AC is that value of AC that causes the same effect (such as heat in a resistor) caused by an equal amount of DC.
Unless specified otherwise, I = E/R for an AC circuit is assumed to mean
The effective value of the current equals the effective value of the voltage divided by the resistance.
What is the equation for calculating the effective value of a sine wave?
The equation for calculating the effective value of a sine wave is: Effective value = 0.707 × peak value.
What is the equation for calculating the average value of any sine wave?
The equation for determining the average value of any sine wave is: Average value = 0.636 × peak value.
It is important to understand how to read the wave forms on the time domain reflectometer (TDR) because they can be distorted by anomalies such as echoes and blind spots. What causes an echo on a waveform TDR?
The extra distance that the TDR pulse travels after initially reflecting off the end of the cable span.
What are the differing forward-path transmission bandwidths for traditional tree-and-branch and HFC architectures?
The feeder system in a traditional tree-and-branch architecture supplies the forward signal up to a 50-550 MHz pass band, and the distribution system in an HFC network transmits the forward signal up to a 50-1,000 MHz pass band.
What is the formula for calculating the total inductance of two inductors connected in parallel, with individual inductance values of L1 and L2?
The formula for calculating the total inductance of two inductors connected in parallel, with individual inductance values of L1 and L2, is: LTotal = 1/(1/L1 + 1/L2).
What happens to a high voltage, low current combination carried on transmission lines when it reaches a transformer located near a power user's home?
The high voltage, low current combination carried on transmission lines is converted to a low voltage, high current combination when it reaches a transformer located near a power user's home.
Many factors influence signal attenuation. What is the effect of temperature on cable signal attenuation?
The higher the temperature, the greater the cable signal attenuation.
What is the relationship between the amount of inductance and the cross-sectional area of the inductor?
The inductance of the inductor is directly proportional to the cross-sectional area of the inductor core.
Why is the broadband cable industry developing its own passive optical network (PON) standard instead of using standards already developed by the International Telecommunication 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 (DOCISIS), and other systems and devices that are still currently being used, but they are not compatible with ITU and IEEE PON standards.
Which of the following statements about instantaneous values is true?
The instantaneous value is the value of a single point on the AC waveform at a specific moment, or instant, of time.
What is the instantaneous value of an AC waveform?
The instantaneous value of an AC waveform is the value of a single point on the waveform at a specific moment or instant of time.
What is the left-hand rule?
The left-hand rule states that when the index finger points in the direction of the magnetic field and the thumb points in the direction that the conductor moves through a magnetic field, the middle finger points in the direction that the electromotive force causes the current to flow.
What is the letter symbol for the inductance of an inductor?
The letter symbol for the inductance of an inductor is the capital letter L.
What is the mathematical equation that expresses Ohm's Law for a resistive AC circuit at any instant of time?
The mathematical equation that expresses Ohm's Law for a resistive AC circuit at any instant of time is i(t) = e(t) ⁄ R, or i = e ⁄ R.
The amplitude of a waveform is defined as
The maximum level of either half-cycle of the waveform.
What are measurement applications for using SLMs, DMMs, TDRs, leakage detectors, and combination leakage detectors?
The measurement applications include: (1) balancing amplifier (bridger, distribution, and line extender) output levels (SLM); (2) verifying system and amplifier power supply operation (DMM); (3) identifying cut or damaged cable spans (TDR); (4) identifying sources of ingress (signal leakage detector, SLM); and (5) monitoring and measuring signal leakage (egress) for system CLI reporting (combination SLM/leakage detector).
What are the most basic parts of a transformer?
The most basic parts of a transformer are a primary winding, one or more secondary windings, and a medium between the primary and secondary windings.
What are three groups of outage causes associated with cut or damaged cables?
The outage groups are: (1) cables cut by underground digging equipment (a backhoe, a trencher, a post-hole digger, a shovel, etc); (2) aerial cable damaged by lightning or downed power lines; and (3) downed aerial cable due to traffic accidents or severe weather.
What is the valence band?
The outer layer, or shell, of electrons surrounding a nucleus.
What is the peak-to-peak value of an AC waveform?
The peak-to-peak value of an AC waveform is the vertical distance between the positive and negative peaks of the waveform.
What type of relationship exists between period and frequency?
The period of one cycle of an AC waveform is inversely proportional to the frequency of that waveform.
What is the phase angle of a point on a waveform?
The phase angle of a point on a waveform is the amount of time indegrees that it takes the waveform to change from the 0° reference point to that point on the waveform.
What happens when a source of DC voltage is applied to the plates of a capacitor?
The plate connected to the positive terminal of the source receives a positive charge.
What is the power consumed by coaxial cable loop resistance when: (1) the current of the coaxial cable circuit is 8 amperes; and (2) the loop resistance of the coaxial cable is 1.07 ohms?
The power consumed by coaxial cable loop resistance is 68.48 watts when: (1) the current of the coaxial cable circuit is 8 amperes; and (2) the loop resistance of the coaxial cable is 1.07 ohms. To calculate: (8 amperes)2 × 1.07 ohms = 64 × 1.07 = 68.48 watts.
- What is the power consumed by the load resistance when: (1) the voltage across the load resistance is 7 volts; and (2) the load resistance is 35 ohms?
The power consumed by the load resistance is 1.4 watts when: (1) the voltage across the load resistance is 7 volts; and (2) the load resistance is 35 ohms. To calculate: (7 volts)2/35 ohms = 49/35 = 1.4 watts.
What is the power loss in the conductors when: (1) the circuit current is 0.8 amperes; (2) the resistance of the conductors is 3 ohms; and (3) eddy current loss and skin-effect loss are considered equal to zero?
The power loss in the conductors is 1.92 watts when: (1) the circuit current is 0.8 amperes; (2) the resistance of the conductors is 3 ohms; and (3) eddy current loss and skin-effect loss are considered equal to zero. To calculate: (0.8 amperes)2 × 3 ohms = 0.64 × 3 = 1.92 watts.
How is power loss due to conversion to heat proportional to the current and resistance in a transmission line?
The power lost due to conversion to heat in a transmission line is directly proportional to the amount of resistance and to the current squared.
What is the main difference between the waveforms of voltage, current, and power in a resistive AC circuit?
The power waveform in a resistive AC circuit has no negative attenuation and no negative peak, as do the voltage and current waveforms.
How are the primary and secondary coils wound in an out-of-phase transformer?
The primary and secondary coils are wound in opposite directions in an out-of-phase transformer.
What is the primary difference between AC and DC waveforms?
The primary difference between AC and DC waveforms is that the magnitude and polarity of an AC waveform changes, while the magnitude and polarity of a DC waveform does not change.
According to the FCC, the leakage log should contain which of the following?
The probable cause of the leakage.
Inductance is
The property of an electrical circuit or conductor that tends to resist changes in the current flowing through the circuit or conductor.
Mutual inductance is
The property possessed by two inductors positioned so that the changing magnetic field lines around one of the inductors encircle, or link, the turns of the other inductor and induce an emf, or voltage, in that inductor.
You are doing an aerial installation of fiber-optic cable. When you survey the installation path, you see that the path runs near several short outbuildings and over a series of hedges. Which installation method should you use?
The pull-in method.
The capacitance of a capacitor is
The ratio of the electric charge transferred from one plate to the other, to the potential difference between the plates caused by the applied voltage.
Which of the following distribution amplifier parts is controlled manually?
The response control.
How does the secondary coil voltage compare to the primary coil voltage in a step-up transformer, in which the secondary coil has more turns than the primary coil?
The secondary coil voltage is larger than the primary coil voltage in a step-up transformer, in which the secondary coil has more turns than the primary coil.
Tap loss is
The signal attenuation between the input port and each tap port at a specific frequency.
What are two reasons why the output signal level from a directional coupler is less than the input signal level?
The signal power sent to the tap port is not available to go to the output port, and the loss in the transformers and other parts of the directional coupler.
What is probably the most common AC waveform?
The sine wave is probably the most common AC waveform.
Three components of the tap housing (and not the tap faceplate) are
The threaded mounting tap, seizure screw mechanisms, and right-angled input and output ports.
What are three principle characteristics that define an AC waveform?
The three principle characteristics that define an AC waveform are: (1) frequency; (2) wavelength; and (3) amplitude.
What is the total inductance of a circuit containing several inductors connected in series?
The total inductance of a circuit containing several inductors connected in series is equal to the sum of all the individual inductances.
In a ferroresonant transformer, what part regulates the load on the secondary winding?
The transformer shunts.
In what two ways is turns ratio expressed?
The turns ratio of the transformer is expressed Np/Nsor Np:Ns.
What are the two types of inductors as classified by the type of core material?
The two types of inductors as classified by the type of core material are air-core inductors and iron-core inductors.
What effective values are assumed in the Ohm's Law equation I = E⁄R for a resistive AC circuit?
The use of I = E ⁄ R with a resistive AC circuit assumes that the values for I and E are the effective values of the current and voltage.
What is the value of the current when: (1) the effective voltage is 20 volts; (2) the resistance of the source is 4 ohms; (3) the resistance of the conductors is 2 ohms; and (4) the resistance of the load is 10 ohms?
The value of the current is 1.25 amps when: (1) the effective voltage is 20 volts; (2) the resistance of the source is 4 ohms; (3) the resistance of the conductors is 2 ohms; and (4) the resistance of the load is 10 ohms. To calculate: 20 volts / (4 ohms + 2 ohms + 10 ohms) = 20/16 = 1.25 amps.
Which of the following statements is true?
The velocity of propagation is the rate that RF signals travel through the coaxial cable versus the speed that RF signals travel in free space.
Which of the following statements is true of a forward-biased silicon diode?
The voltage drop across the diode is approximately 0.7 volt.
Describe the three types of voltage or current increases in a sine wave, square wave, and sawtooth wave AC waveforms.
The voltage or current increase is nonlinear in a sine wave, instantaneous in a square wave, and linear in a sawtooth wave AC waveform.
It is important to use safety precautions when using a time domain reflectometer (TDR) in order to avoid electrical shock. What is the primary source of the electrical hazard?
The voltages in the coaxial cable.
How are the terms "lead" and "lag" used to describe two out-of-phase waveforms?
The waveform or generator output that completes a cycle first "leads" the other waveform or output, while the output or waveform that completes a cycle after the other "lags" the other output or waveform.
Why would a three-way unbalanced splitter be used in a system design?
There is a need for one of the three output ports to have a lower insertion loss than the other two ports.
Which type of signal level control uses passive circuitry to maintain a constant output signal level on a line extender?
Thermal control.
What is the state of the RF signals in a line extender when they are fed into the pre-amplifier?
They are in a flat state.
Schottky barrier diodes are popular as rectifiers because
They have a lower voltage drop than do silicon diodes.
How is an AC resistive circuit the same as a DC resistive circuit?
They have similar Ohm's law and power relationships, with certain exceptions.
How many gaskets do hardline two-way RF splitters have? They have two gaskets, an RFI gasket and an environmental gasket.
They have two gaskets, an RFI gasket and an environmental gasket.
To connect a coaxial cable to a 750 MHz amplifier, use a
Three-piece or two-piece pin connector.
A simple AC generator containing a wire loop rotating between the poles of a magnet produces AC voltage
Through magnetism and mechanical motion
Capacitor charging
Time is directly related to the size of the circuit resistance and the capacitance of the capacitor.
Combination coring/stripping tools are used
To core the dielectric while simultaneously stripping and beveling the aluminum sheath.
When preparing armored cable for connectorization, a tubing cutter is used
To cut all the way through the outer jacket and steel armoring so they can be removed using a knife and pliers.
In a fiber-optic cable, what is the purpose of the cladding?
To guide light down the fiber.
There are three filtering networks in a power inserter. What is the purpose of the high-pass filter?
To prevent the 60 VAC or 90 VAC from passing between the two RF/AC ports.
Many cable operators have a drop certification program and require measurements using a digital signal analyzer with minimum and maximum criteria programmed into the instrument. Why should the technician recognize and understand which channels are being measured when automated measurements are being performed by the digital signal analyzer?
To save measurement time, some cable operators perform automated measurements on a sample of channels which can result in problems going undetected in unmeasured channels.
What is the purpose of a back-facet diode in an optical transmitter?
To sense the light level being put out by the diode.
A time domain reflectometer (TDR) can be used to test the impedance continuity of a new reel of coaxial cable. What is the purpose of testing the same cable for impedance continuity after it is installed?
To test for damage to the cable.
Preventive maintenance can include the use of special modules that track data and communicate it to the headend, which are placed inside amplifiers and power supplies. What are these modules called?
Transponders.
How are true AC waveforms symmetrical?
True AC waveforms are symmetrical about the horizontal axis.
In abnormal coaxial cable attenuation changes,
Trunk and feeder cable can also possess imperfections that cause random differences in attenuation at different frequencies.
What is turns ratio?
Turns ratio is the ratio between the number of turns in the primary coil and the number of turns in the secondary coil of a transformer.
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.
What are two commonly used values for inductance?
Two common values used for inductance are millihenry (mh) and microhenry (μh).
How is underground cable manufactured?
Underground cable is manufactured with a protective outer jacket covering the aluminum sheath and flooding compound between the jacket and the sheath.
Which typical over-the-air signal sources can cause a false alarm with a signal leakage detector?
Typical sources include aircraft communication signals and ham, mobile, and government radio broadcasts.
The polyethylene jacket on non-armored coaxial cable should be removed
Using the correct jacket or non-armored coaxial cable should be removed
What is usually displayed on the vertical and horizontal axes of an AC waveform graph?
Usually, the voltage or current is displayed on the vertical axis and time is displayed on the horizontal axis of an AC waveform graph.
What is the phase relationship between voltage and current in a resistive AC circuit?
Voltage and current in a resistive AC circuit are always in-phase with each other.
What is the phase relationship between voltage, current, and power in a resistive AC circuit?
Voltage, current, and power are all in-phase in a resistive AC circuit.
Define wavelength.
Wavelength is the physical distance that one impulse of current travels during the time it takes to complete one cycle of the voltage waveform. It also is defined as the physical length of one cycle of the AC voltage waveform.
Which of the following is used to define the waveform of an optical signal?
Wavelength.
What happens to the individual magnetic fields of the electrons in a conductor when a DC voltage is applied?
When a DC voltage is applied to a conductor, the individual magnetic fields of the lectrons combine almost instantly to create one large magnetic field extending outside of and surrounding the conductor.
There are many ways that cable signals can be "pirated," or taken without compensation to the cable operator. Which of the following is an example of passive piracy?
When an installer does not have a trap during basic service installation.
Which of the following statements is true?
When the capacitor plates have no charges on them, no electric field exists between the plates.
Which statement characterizes a directional coupler?
Which statement characterizes a directional coupler?
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.
A transformer
is either an air-core or an iron-core transformer.
