3D1X3 Vol 1 CDC Ed 2
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(001) What are the three general categories used to produce modulation in radio frequency (RF) transmission today?
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Binary amplitude shift keying, frequency shift keying, and phase shift keying.
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Pulse amplitude, pulse width, and pulse position.
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Amplitude, frequency, and phase.
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Analog, digital and shift keying.
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The '3d1x3 Vol 1 CDC Ed 2' quiz assesses knowledge on RF modulation techniques, including why modulation is used, types of modulation, and calculations for modulation percentages. It is crucial for understanding effective long-distance RF transmission and is tailored for individuals in military communications roles.
Quiz Preview
- 2.
(015) At what level does the Air Force want electromagnetic interference problems resolved?
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Affected unit.
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Affected major command.
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Electromagnetic environmental effects office.
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Spectrum interference resolution office.
Correct Answer
A. Affected unit.Explanation
The Air Force wants electromagnetic interference problems to be resolved at the level of the affected unit. This means that the responsibility for resolving these problems lies with the specific unit that is experiencing the interference. It is important for the affected unit to address and resolve these issues in order to ensure proper functioning of their equipment and operations.Rate this question:
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- 3.
(015) Who is initially responsible for reporting an electromagnetic interference?
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The operator.
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Major command.
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The frequency manager.
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Federal Communications Commission.
Correct Answer
A. The operator.Explanation
The operator is initially responsible for reporting an electromagnetic interference. This means that it is the operator's duty to identify and report any instances of electromagnetic interference that may occur. The operator plays a crucial role in ensuring that any interference is promptly reported and addressed, as they are the first line of defense in maintaining the integrity and effectiveness of the electromagnetic spectrum.Rate this question:
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- 4.
(017) When you use the Fluke 8025A, which voltage range do you select to measure 50 volts DC?
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Volts AC.
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Volts DC.
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Millivolts AC.
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Millivolts DC.
Correct Answer
A. Volts DC.Explanation
When using the Fluke 8025A to measure 50 volts DC, you would select the "Volts DC" voltage range. This is because the Fluke 8025A is a multimeter that is designed to measure different types of voltages, including AC and DC. In this case, since you are measuring a direct current voltage of 50 volts, you would select the "Volts DC" range to obtain an accurate measurement.Rate this question:
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- 5.
(023) What type of equipment helps resolve intermittent electrical problems because of poor grounding?
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Earth ground tester.
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Frequency counter.
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Spectrum analyzer.
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Oscilloscope.
Correct Answer
A. Earth ground tester.Explanation
An earth ground tester helps resolve intermittent electrical problems caused by poor grounding. Poor grounding can lead to electrical issues such as voltage fluctuations, electrical noise, and equipment malfunctions. An earth ground tester measures the resistance between an electrical system and the earth, ensuring that the grounding is adequate. By identifying and fixing poor grounding, an earth ground tester can help eliminate intermittent electrical problems.Rate this question:
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- 6.
(040) What type of uninterruptible power supply (UPS) has traditionally been referred to as “offline” by technicians?
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Passive standby.
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Line interactive.
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Double conversion.
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Ferro resonant standby.
Correct Answer
A. Passive standby.Explanation
Passive standby is the type of uninterruptible power supply (UPS) that has traditionally been referred to as "offline" by technicians. This type of UPS operates by allowing the connected equipment to run directly from the main power source while also providing backup power in case of an outage. The UPS only switches to battery power when there is a power failure, hence the term "offline." This type of UPS is typically less expensive and more energy-efficient compared to other types.Rate this question:
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- 7.
(023) How often must you continue to test system grounds?
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Randomly.
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Periodically.
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Every 10 years.
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Just one time only.
Correct Answer
A. Periodically.Explanation
Periodically testing system grounds is necessary to ensure the effectiveness and safety of the grounding system. Grounding systems can deteriorate over time due to environmental factors, corrosion, or wear and tear. By testing system grounds regularly, any potential issues can be identified and addressed promptly, preventing electrical hazards and ensuring the proper functioning of the system. Random testing or testing only once may not provide a comprehensive assessment of the grounding system's condition. Therefore, periodic testing is essential to maintain the integrity of the system.Rate this question:
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- 8.
(027) A power reading that uses the abbreviation dBm indicates the
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Ratio of decibels relative to a 1-milliwatt standard.
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Ratio of decibels relative to a 1-megawatt standard.
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Actual power level expressed in milliwatts.
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Actual power level expressed in megawatts.
Correct Answer
A. Ratio of decibels relative to a 1-milliwatt standard.Explanation
A power reading that uses the abbreviation dBm indicates the ratio of decibels relative to a 1-milliwatt standard. This means that the power level being measured is compared to a reference power level of 1 milliwatt. The dBm unit allows for a convenient and standardized way to express power levels in terms of decibels.Rate this question:
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- 9.
(001) What is one reason for modulation that involves modulatiing low frequency signals for transmission over long distances?
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Spectrum Conservation
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Channel allocation
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Ease of radiation
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Companding
Correct Answer
A. Ease of radiationExplanation
Modulating low frequency signals for transmission over long distances allows for ease of radiation. This means that the modulated signal can be easily transmitted and propagated through the air or other medium without significant loss or degradation. By modulating the low frequency signals, they can be converted into higher frequency signals that are more suitable for long distance transmission. This process makes it easier to transmit the signals over long distances without the need for complex and expensive equipment.Rate this question:
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- 10.
(003) A 5 kHz modulating signal has enough peak voltage to cause a deviation of 15 kHz. What is the modulation index?
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5
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0.5
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0.3
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3
Correct Answer
A. 3Explanation
The modulation index is a measure of the extent of frequency deviation in a frequency modulation (FM) signal. It is calculated by dividing the peak frequency deviation by the modulating frequency. In this case, the modulating signal has a frequency of 5 kHz and causes a deviation of 15 kHz. Therefore, the modulation index is 15 kHz / 5 kHz = 3.Rate this question:
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- 11.
(008) What type of light is emitted from a laser?
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Incoherent.
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Coherent.
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Ordinary.
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Invisible.
Correct Answer
A. Coherent.Explanation
A laser emits coherent light. Coherent light is characterized by its uniformity in wavelength and phase, meaning that all the light waves are in sync and have a consistent frequency. This is achieved through a process called stimulated emission, where photons are released in a controlled manner. Unlike ordinary light sources, such as a light bulb, which emit incoherent light with various wavelengths and phases, a laser produces a narrow, focused beam of light that is highly concentrated and can travel long distances without significant spreading or divergence.Rate this question:
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- 12.
(017) When testing a diode with the 8025A, the leads across a “good” diode produces an “OL” (open) on the display in one direction while reversing the leads produces
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A continuous audible tone.
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“SL” (short) on the display.
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A wavering audible tone.
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Three short beeps.
Correct Answer
A. A continuous audible tone.Explanation
When testing a diode with the 8025A, a "good" diode should produce an "OL" (open) on the display when the leads are connected in one direction. However, when the leads are reversed, a continuous audible tone should be produced. This indicates that the diode is functioning properly and allowing current to flow in both directions.Rate this question:
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- 13.
(040) What power line fault category is more typically referred to as Electro-Magnetic Interference and Radio Frequency Interference?
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Sag.
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Spike.
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Noise.
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Blackout.
Correct Answer
A. Noise.Explanation
The correct answer is Noise. Noise refers to the interference caused by electromagnetic and radio frequency signals, which can disrupt the normal functioning of power lines. Sag refers to a temporary drop in voltage, spike refers to a sudden increase in voltage, and blackout refers to a complete loss of power.Rate this question:
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- 14.
(036) What are the three main functions of grounding?
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Personnel safety, equipment protection, and noise reduction.
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Signal amplification, personnel safety, and emissions security.
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Equipment protection, signal amplification, and capacitance reaction.
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Corrosion prevention, emissions security, and over-voltage protection.
Correct Answer
A. Personnel safety, equipment protection, and noise reduction.Explanation
Grounding serves three main functions: personnel safety, equipment protection, and noise reduction. Grounding helps to prevent electric shock by providing a path for electrical current to flow safely into the ground. It also protects equipment by providing a reference point for voltage and reducing the risk of damage from electrical faults. Additionally, grounding helps to reduce noise and interference in electrical systems, improving the overall performance and reliability of the system.Rate this question:
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- 15.
(009) What photo detector converts one photon to one electron?
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Light emitting diode.
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Avalanche photodiode.
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Positive intrinsic negative diode.
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Integrated photodiode/preamplifier.
Correct Answer
A. Positive intrinsic negative diode.Explanation
The correct answer is Positive intrinsic negative diode because this type of diode, also known as PIN diode, is capable of converting one photon to one electron. It has a heavily doped P region and a heavily doped N region, with an intrinsic region in between. When a photon is absorbed by the intrinsic region, it creates an electron-hole pair, and the electric field in the diode causes the electron to move towards the N region, resulting in the conversion of one photon to one electron.Rate this question:
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- 16.
(014) How can you normally eliminate electromagnetic interference noise bursts caused by sodium and mercury vapor lights that have stopped working while the power is still applied?
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Change the bulb.
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Ground out the light fixture.
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Install a noise reject filter on the light.
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Install a noise reject filter on the receiver.
Correct Answer
A. Change the bulb.Explanation
Sodium and mercury vapor lights can emit electromagnetic interference when they are not functioning properly. This interference can cause noise bursts in electronic devices. By changing the bulb, the issue can be resolved as a faulty bulb may be the cause of the interference.Rate this question:
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- 17.
(020) What area of a digital storage oscilloscope takes digitized samples and performs numerous anipulations on the data including measuring rise and fall times, periods, time intervals, and ath computations?
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Microprocessors.
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Acquisition.
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Memory.
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Input.
Correct Answer
A. Microprocessors.Explanation
The area of a digital storage oscilloscope that takes digitized samples and performs numerous manipulations on the data including measuring rise and fall times, periods, time intervals, and math computations is the microprocessors. This is because microprocessors are responsible for processing the digitized samples and performing various calculations and measurements on the data.Rate this question:
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- 18.
(022) Which of these bit rates do you use for a bit error rate test on a 64 kbps data circuit?
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511 bps.
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9600 bps.
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64 kbps.
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1.544 Mbps.
Correct Answer
A. 64 kbps.Explanation
The correct answer is 64 kbps. This is the bit rate that should be used for a bit error rate test on a 64 kbps data circuit. Bit error rate testing is used to measure the quality of a digital transmission system by intentionally introducing errors and measuring the error rate. In this case, since the data circuit has a bit rate of 64 kbps, it makes sense to use the same bit rate for the test.Rate this question:
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- 19.
(002) If a carrier frequency of 1 MHz and a modulating tone of 10 kHz goes to the modulator, the output signal include
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1.01 MHz, 1 MHz, and 0.99 MHz.
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1.1 MHz, 1 MHz, and 0.9 MHz.
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1.11 MHz, 1 MHz, 0.99 MHz.
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1.111 MHz, 1 MHz, 0.999 MHz.
Correct Answer
A. 1.01 MHz, 1 MHz, and 0.99 MHz.Explanation
When a carrier frequency of 1 MHz and a modulating tone of 10 kHz are input into the modulator, the output signal will include the carrier frequency (1 MHz), the sum of the carrier frequency and the modulating tone (1.01 MHz), and the difference between the carrier frequency and the modulating tone (0.99 MHz).Rate this question:
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- 20.
(003) In frequency modulation, a significant sideband contains at least what percentage of the total transmitted power?
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1
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3
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10
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0.1
Correct Answer
A. 1Explanation
In frequency modulation, a significant sideband contains at least 1% of the total transmitted power.Rate this question:
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- 21.
(003) What is the formula to find the modulating index?
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Deviation divided by frequency of modulation.
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Deviation times frequency of modulation.
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Sideband divide by carrier frequency.
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Sideband times carrier frequency.
Correct Answer
A. Deviation divided by frequency of modulation.Explanation
The formula to find the modulating index is deviation divided by frequency of modulation. This formula is used to calculate the extent of variation in the carrier wave caused by the modulating signal. The modulating index represents the ratio of the maximum frequency deviation to the frequency of the modulating signal. By dividing the deviation by the frequency of modulation, we can determine the modulating index and understand the degree of modulation in the carrier wave.Rate this question:
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- 22.
What man-made noise results from voltage surges, arcing, or corona discharges?
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Relays.
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Lighting.
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Power line.
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Switching equipment.
Correct Answer
A. Power line.Explanation
Voltage surges, arcing, and corona discharges can cause disturbances in power lines, resulting in man-made noise. This noise can be generated due to the fluctuations in voltage, the arcing of electricity, or the corona discharges occurring along the power line. Therefore, the correct answer is power line.Rate this question:
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- 23.
(016) Which feature of the Fluke 8025A multimeter do you use to select various measurement functions?
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Circuit jacks.
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Rotary switch.
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Range push button.
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Touch-hold button.
Correct Answer
A. Rotary switch.Explanation
The rotary switch is the feature of the Fluke 8025A multimeter that allows you to select various measurement functions. The rotary switch is a dial that can be turned to different positions, each corresponding to a specific measurement function such as voltage, current, resistance, or continuity. By rotating the switch to the desired function, you can easily select and switch between different measurement modes on the multimeter.Rate this question:
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- 24.
(016) Which feature of the Fluke 8025A locks the measurement into the display for viewing and automatically updates the display when you take a new measurement?
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Rotary switch.
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Range push button.
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Power-up self-test.
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Touch-hold push button.
Correct Answer
A. Touch-hold push button.Explanation
The touch-hold push button feature on the Fluke 8025A locks the measurement into the display for viewing and automatically updates the display when a new measurement is taken. This means that once a measurement is made, it will remain on the screen until a new measurement is taken, ensuring that the user can easily view and compare the results without the need to constantly hold down a button.Rate this question:
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- 25.
(033) What operational capability of the communication service monitor produce sine, square and triangle waveforms?
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Scope.
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Duplex.
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Receiver
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Function generator.
Correct Answer
A. Function generator.Explanation
The operational capability of a communication service monitor to produce sine, square, and triangle waveforms is known as a function generator. A function generator is a versatile tool that can generate a variety of waveforms with different frequencies and amplitudes. It is commonly used in testing and troubleshooting electronic devices and communication systems.Rate this question:
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- 26.
(002) The bandwidth of an amplitude modulated signal is
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Two times the modulating signal.
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The same as the modulating signal.
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Determined by the modulation index.
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Defined in terms of maximum amount of modulation.
Correct Answer
A. Two times the modulating signal.Explanation
The bandwidth of an amplitude modulated signal is two times the modulating signal. This means that the range of frequencies needed to accurately represent the modulating signal is twice the highest frequency present in the modulating signal. This is because in amplitude modulation, the sidebands are located above and below the carrier frequency, and their width is equal to the highest frequency in the modulating signal. Therefore, the total bandwidth required to transmit the modulated signal is twice the modulating signal's bandwidth.Rate this question:
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- 27.
(006) If an error should occur, what transmission is lost in an synchronous transmission?
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One Character
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Block of data
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A parity bit
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A stop bit
Correct Answer
A. Block of dataExplanation
In synchronous transmission, data is sent in blocks rather than individual characters. Each block of data is transmitted as a single unit and is synchronized with the clock signal. If an error occurs during transmission, the entire block of data may be lost, resulting in the loss of multiple characters. Therefore, in synchronous transmission, the block of data is lost if an error occurs.Rate this question:
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- 28.
(010) Which repeater amplifies optical signal without converting to and from the electrical domain?
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Receiver.
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Repeaters.
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Regenerators.
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Optical amplifiers.
Correct Answer
A. Optical amplifiers.Explanation
Optical amplifiers are devices that amplify optical signals directly without converting them to electrical signals. Unlike repeaters, which regenerate and amplify electrical signals, optical amplifiers work in the optical domain, amplifying the signal without the need for conversion. Therefore, optical amplifiers are the correct answer for this question.Rate this question:
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- 29.
(002) Which statement concerning bandwidth is true?
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Overmodulating increases bandwidth because the distortion produces harmonics.
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Undermodulating increases bandwidth because the distortion produces harmonics.
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Overmodulating increases bandwidth because the output’s increased amplitude.
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Undermodulating increases bandwidth because the output’s decreased amplitude.
Correct Answer
A. Overmodulating increases bandwidth because the distortion produces harmonics.Explanation
Overmodulating increases bandwidth because the distortion produces harmonics. When a signal is overmodulated, the amplitude of the signal exceeds the maximum limit, causing distortion. This distortion results in the creation of additional frequencies known as harmonics. These harmonics increase the overall bandwidth of the signal as they occupy additional frequency space. Therefore, overmodulating a signal leads to an increase in bandwidth due to the presence of harmonics.Rate this question:
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- 30.
(004) In phase modulation, what part of the carrier signal is varied?
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Frequency
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Amplitude
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Height
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Phase
Correct Answer
A. PhaseExplanation
In phase modulation, the part of the carrier signal that is varied is the phase. This means that the timing of the carrier signal is adjusted in order to encode the information being transmitted. By changing the phase of the carrier signal, different symbols or bits can be represented, allowing for the transmission of data.Rate this question:
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- 31.
(007) When using forward error control as a method of error correction, where does error correction take place?
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Receiving end.
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In the oscillator.
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Transmitting end.
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In the primary buffers.
Correct Answer
A. Receiving end.Explanation
Error correction takes place at the receiving end when using forward error control as a method of error correction. This means that the errors are detected and corrected after the data has been transmitted and received by the intended recipient. The receiving end is responsible for identifying any errors in the received data and applying the necessary corrections to ensure the accuracy and integrity of the transmitted information.Rate this question:
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- 32.
(011) Which fiber-optic connector uses quick-release, keyed bayonet couplings that are preferred in situations where severe vibrations are not expected?
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Biconic.
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Field (FC).
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Straight tip (ST).
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Sub-miniature, type A (SMA).
Correct Answer
A. Straight tip (ST).Explanation
The straight tip (ST) fiber-optic connector uses quick-release, keyed bayonet couplings that are preferred in situations where severe vibrations are not expected. This means that the ST connector is designed to provide a secure and stable connection while still being easy to install and remove. The quick-release feature allows for quick and convenient installation and removal, while the keyed bayonet couplings ensure a secure and reliable connection. This makes the ST connector a suitable choice for applications where vibrations are not a concern.Rate this question:
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- 33.
(020) What type of sampling does a digital storage oscilloscope normally use on single-shot or seldom-occurring signals?
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Sequential
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Repetitive.
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Real-time.
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Random.
Correct Answer
A. Real-time.Explanation
A digital storage oscilloscope (DSO) normally uses real-time sampling on single-shot or seldom-occurring signals. Real-time sampling allows the DSO to capture and display the waveform accurately, without missing any details or distortions that may occur in the signal. This is important for capturing transient or unpredictable events, as the DSO can capture and store the waveform in real-time for analysis and measurement. Sequential sampling would not be suitable for single-shot or seldom-occurring signals, as it may miss important information between samples. Repetitive sampling is used for periodic signals, and random sampling is not commonly used in DSOs.Rate this question:
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- 34.
(034) Why should the number of splices be controlled during fiber optic installation?
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Prevent eavesdropping.
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To aid in troubleshooting.
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Reduce potential damage.
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Minimize transmission loss.
Correct Answer
A. Minimize transmission loss.Explanation
Controlling the number of splices during fiber optic installation is important to minimize transmission loss. Splices are points where two fiber optic cables are joined together, and each splice introduces a certain amount of signal loss. By minimizing the number of splices, the overall transmission loss can be reduced, ensuring that the signal strength remains strong throughout the fiber optic network. This is crucial for maintaining optimal performance and ensuring that data can be transmitted over long distances without significant degradation.Rate this question:
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- 35.
(006) In asynchronous transmissions, what bit is used by the receiving device to verify that the transmission was received correctly?
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Control
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Parity
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Start
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Stop
Correct Answer
A. ParityExplanation
Parity is used in asynchronous transmissions to verify that the transmission was received correctly. Parity is a bit that is added to the data being transmitted. The receiving device checks the parity bit to ensure that the number of bits set to 1 in the data is either even or odd, depending on the type of parity being used. If the parity check fails, it indicates that there was an error in the transmission.Rate this question:
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- 36.
(007) When using vertical redundancy check, what significance does the amount of ones have in a data bit pattern?
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Determines parity.
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Determines transmission rate.
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Determines whether transmission is in ASCII format.
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Determines whether transmission is synchronous or asynchronous.
Correct Answer
A. Determines parity.Explanation
The amount of ones in a data bit pattern determines the parity. Parity is a form of error checking where an extra bit is added to a data transmission to ensure that the number of ones in the transmission is always even or odd. By checking the parity bit, the receiver can detect if any errors occurred during transmission.Rate this question:
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- 37.
(014) If the interference can be eliminated by disconnecting the receiving antenna, the source of the disturbance is most likely
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Line noise.
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Internal to the radio.
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External to the radio.
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Radio receiver trouble.
Correct Answer
A. External to the radio.Explanation
If disconnecting the receiving antenna eliminates the interference, it suggests that the source of the disturbance is external to the radio. This means that the interference is coming from an external source, such as another electronic device or a nearby power line, rather than being caused by a fault within the radio itself.Rate this question:
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- 38.
(015) What do you do when you are reasonably sure electromagnetic interference exists?
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Request engineering assistance.
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Contact the base frequency manager.
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Systematically gather data for analysis.
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Contact the spectrum interference resolution office.
Correct Answer
A. Systematically gather data for analysis.Explanation
When you are reasonably sure electromagnetic interference exists, the best course of action is to systematically gather data for analysis. This involves collecting information about the interference, such as its frequency, intensity, and duration, in order to better understand its source and potential impact on the system. This data can then be analyzed to determine the appropriate steps to mitigate or resolve the interference. Requesting engineering assistance or contacting the base frequency manager or spectrum interference resolution office may be necessary at a later stage, but the initial step is to gather data for analysis.Rate this question:
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- 39.
(020) In acquiring a 4K record length on a digital storage oscilloscope, how many samples can you view at one time?
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1,000.
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2,000.
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3,000.
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4,000.
Correct Answer
A. 1,000.Explanation
The correct answer is 1,000. A 4K record length on a digital storage oscilloscope means that the oscilloscope can store 4,000 samples of waveform data. However, it does not necessarily mean that you can view all 4,000 samples at once. The oscilloscope's display screen may have a limited size, and it may only be able to display a certain number of samples at a time. In this case, the oscilloscope can only display 1,000 samples at one time.Rate this question:
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- 40.
(024) Resistance reading on the ground under test is plotted on a graph of
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Resistance versus distance.
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Current versus distance.
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Frequency versus time.
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Amplitude versus time.
Correct Answer
A. Resistance versus distance.Explanation
The correct answer is resistance versus distance. This is because the question is asking about the reading on the ground under test, which implies that the resistance is being measured at different distances. The resistance reading is then plotted on a graph, with the x-axis representing distance and the y-axis representing resistance. This graph allows for a visual representation of how the resistance changes with distance.Rate this question:
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- 41.
(002) When the modulating signal and carrier signal are combined within a modulator, the output signal contains
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Modulating signal, upper sideband, and lower sideband.
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Carrier, upper sideband, and lower sideband.
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Upper sideband and modulating signal.
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Carrier and modulating signal.
Correct Answer
A. Carrier, upper sideband, and lower sideband.Explanation
When the modulating signal and carrier signal are combined within a modulator, the resulting output signal will contain the carrier signal as well as the upper and lower sidebands. The carrier signal is the original unmodulated signal, while the upper sideband represents the frequencies above the carrier frequency and the lower sideband represents the frequencies below the carrier frequency. Therefore, the correct answer is that the output signal contains the carrier, upper sideband, and lower sideband.Rate this question:
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- 42.
(003) What is it called when a narrow frequency band between adjacent stations prevent frequency modulated sidebands from overlapping?
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Space
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Guard Band
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Buffer zone
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Prevention field
Correct Answer
A. Guard BandExplanation
A guard band is a narrow frequency band that is used to prevent frequency modulated sidebands from overlapping between adjacent stations. It acts as a buffer zone or prevention field to ensure that the signals do not interfere with each other. This helps to maintain the clarity and integrity of the transmitted signals and prevents any distortion or overlap that could occur if the frequencies were not properly separated.Rate this question:
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- 43.
(004) In phase modulation, the carrier’s
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Phase is shifted at the rate of the modulating signal.
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Phase shifted with the phase of the modulating signal.
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Amplitude is shifted at the rate of the modulating signal.
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Amplitude is shifted with the phase of the modulating signal.
Correct Answer
A. Phase is shifted at the rate of the modulating signal.Explanation
In phase modulation, the phase of the carrier signal is shifted at the rate of the modulating signal. This means that the instantaneous phase of the carrier signal is varied according to the amplitude of the modulating signal. This allows for the transmission of information by encoding it in the changes in phase of the carrier signal.Rate this question:
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- 44.
(005) What part of the pulse code modulation process converts a continuous time signal into a discrete time signal?
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Sampling
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Rectifying
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Oscillating
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Band Limiting
Correct Answer
A. SamplingExplanation
Sampling is the part of the pulse code modulation process that converts a continuous time signal into a discrete time signal. In this process, the continuous time signal is sampled at regular intervals to obtain a series of discrete samples. These samples represent the amplitude of the signal at specific points in time. Sampling is essential to convert analog signals into digital signals, which can be processed and transmitted more efficiently.Rate this question:
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- 45.
(008) Light sources that are applicable to fiber optic waveguide are light-emitting diodes and
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Photo transistors.
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Hybrid photodiodes.
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Semiconductor laser diodes.
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Integrated photodiode/preamplifiers.
Correct Answer
A. Semiconductor laser diodes.Explanation
Semiconductor laser diodes are applicable to fiber optic waveguides because they can generate coherent light with a narrow beam divergence. This makes them suitable for transmitting light signals over long distances through the fiber optic cables. Light-emitting diodes (LEDs) can also be used, but they are less efficient and have a wider beam divergence. Photo transistors and integrated photodiode/preamplifiers are used for detecting the light signals in the fiber optic system, but they are not used as the light source. Hybrid photodiodes are not commonly used in fiber optic waveguides.Rate this question:
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- 46.
(012) A system-generated electromagnetic pulse is a problem for satellites and reentry vehicles that are
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Susceptible to the wideband frequency phenomenon.
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Directly exposed to nuclear radiations from a high-altitude burst.
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Affected by the azimuthal magnetic fields and time-varying air conductivity.
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Influenced by the signal fading or waveform distortion caused by the structured plasma field.
Correct Answer
A. Directly exposed to nuclear radiations from a high-altitude burst.Explanation
Satellites and reentry vehicles can be affected by a system-generated electromagnetic pulse if they are directly exposed to nuclear radiations from a high-altitude burst. This means that if these vehicles are in close proximity to a high-altitude nuclear explosion, the resulting radiation can cause disruptions to their systems. This is because the electromagnetic pulse generated by the explosion can interfere with the electronics and communication systems of these vehicles, potentially causing malfunctions or damage.Rate this question:
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- 47.
(014) Which type of intermodulation interference varies significantly with temperature and weather conditions?
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Transmitter.
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Rusty-bolt.
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Spurious
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Receiver.
Correct Answer
A. Rusty-bolt.Explanation
Rusty-bolt interference is a type of intermodulation interference that is caused by the presence of rusty or corroded metal objects in the vicinity of the radio communication system. This type of interference can vary significantly with temperature and weather conditions because these factors can affect the conductivity and resistance of the rusty metal, leading to changes in the level of interference.Rate this question:
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- 48.
(029) The two switches on the front panel of the wattmeter correspond to the
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Power range of the reverse element.
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Power range of the forward element.
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Frequency range of the reverse element.
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Frequency range of the forward element.
Correct Answer
A. Power range of the forward element.Explanation
The two switches on the front panel of the wattmeter correspond to the power range of the forward element. This means that the switches control the power range that the forward element of the wattmeter can measure. The forward element of the wattmeter is responsible for measuring the power flowing in the forward direction, so the switches allow the user to select the appropriate power range for their measurement needs.Rate this question:
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- 49.
(041) How many phases of generator power are usually required for industrial and commercial applications?
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Single.
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Double.
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Three.
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Four.
Correct Answer
A. Three.Explanation
For industrial and commercial applications, three phases of generator power are usually required. This is because three-phase power provides a more balanced and efficient distribution of electrical power compared to single or double phases. Three-phase power allows for higher power transmission capacity, increased stability, and reduced voltage drop. It is the standard choice for powering heavy machinery and large-scale operations in industrial and commercial settings.Rate this question:
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Mar 21, 2023Quiz Edited by
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Oct 21, 2013Quiz Created by
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