3D1X3 CDC Volume 1 Ure
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(015) Who is initially responsible for reporting an electromagnetic interference (EMI)?
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The operator.
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Major command (MAJCOM).
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The frequency manager (FM).
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Federal Communications Commission (FCC).
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This quiz, titled '3D1X3 CDC Volume 1 URE', assesses knowledge on RF transmission, focusing on modulation techniques such as amplitude, frequency, and phase. It is designed for learners in the Air Force, enhancing understanding of signal transmission and modulation for effective long-distance communication.
Quiz Preview
- 2.
(023) System grounds must continually be tested
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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
System grounds must be periodically tested to ensure that they are functioning properly. Grounding systems are essential for electrical safety as they provide a path for fault currents to flow, preventing electrical shock hazards and equipment damage. Over time, grounds can deteriorate due to corrosion, moisture, or other factors, leading to an ineffective grounding system. Regular testing allows for the identification and correction of any issues, ensuring the continued safety and reliability of the electrical system.Rate this question:
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- 3.
(013) Which one of the following statements are true converning shielding?
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Cables should be of unshielded construction.
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Only ventilation ports are shielded along the walls.
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Sensitive equipment will be located within the shielded barrier.
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All power lines supplying shielded areas does not require filters.
Correct Answer
A. Sensitive equipment will be located within the shielded barrier. -
- 4.
(014) What is an example of intentionally induced electromagnetic interference (EMI)?
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Jamming.
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Spurious responses.
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Intermodulation.
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Power line noise.
Correct Answer
A. Jamming.Explanation
Jamming is an example of intentionally induced electromagnetic interference (EMI). Jamming refers to the deliberate transmission of signals to disrupt or interfere with the operation of electronic devices or communication systems. It is often used in military operations to disrupt enemy communications or radar systems. Jamming can cause interference and disrupt the normal functioning of electronic equipment, causing a loss of signal or degraded performance. Spurious responses, intermodulation, and power line noise are examples of unintentional EMI, caused by factors such as faulty equipment, electromagnetic radiation from other sources, or electrical noise in power lines.Rate this question:
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- 5.
(015) At what level does the Air Force want electromagnetic interference (EMI) 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 (EMI) problems resolved at the level of the affected unit. This means that the responsibility for resolving EMI problems lies with the specific unit that is experiencing the interference. This approach ensures that the unit directly affected by the EMI is responsible for finding a solution and taking appropriate action. It also allows for a more efficient resolution process, as the unit experiencing the interference is likely to have the most knowledge and understanding of the specific situation.Rate this question:
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- 6.
(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.
Correct Answer
A. Amplitude, frequency, and phase.Explanation
The three general categories used to produce modulation in radio frequency (RF) transmission today are amplitude, frequency, and phase. These categories refer to the different ways in which the RF signal can be modified to carry information. Amplitude modulation (AM) involves varying the amplitude of the RF signal to encode information. Frequency modulation (FM) involves varying the frequency of the RF signal. Phase modulation (PM) involves varying the phase of the RF signal. These modulation techniques are widely used in RF communication systems to transmit and receive information.Rate this question:
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- 7.
(013) What is the purpose of bonding?
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To isolate facility from any external electrical electromagnetic propagation.
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To reduce interference coupling around circuits and around interconnecting lines.
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To ensure a mechanically strong, low impedance interconnection between metal objects.
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To eliminate harmful differences of potential between the various telephone cables entering facility.
Correct Answer
A. To ensure a mechanically strong, low impedance interconnection between metal objects.Explanation
The purpose of bonding is to ensure a mechanically strong, low impedance interconnection between metal objects. This helps to create a reliable and efficient electrical pathway between the objects, reducing resistance and preventing the build-up of harmful differences in potential. By providing a secure bond, bonding also helps to minimize the risk of electrical shock and damage caused by electrical faults.Rate this question:
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- 8.
(017) Which current range on the Fluke 8025A do you select to measure 250 milliamps alternating current (AC)?
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Microamps direct current (DC).
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Microamps AC.
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Milliamps/amp DC.
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Milliamps/amp AC.
Correct Answer
A. Milliamps/amp AC.Explanation
To measure 250 milliamps alternating current (AC) on the Fluke 8025A, you would select the "Milliamps/amp AC" current range. This range is specifically designed to measure AC current in milliamps and is the most appropriate choice for this particular measurement.Rate this question:
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- 9.
(021) What test equipment provides a bit error detection system that can determine the received data quality after traveling over a communications link?
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Megger.
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Multimeter.
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Oscilloscope.
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Bit error rate (BER).
Correct Answer
A. Bit error rate (BER).Explanation
Bit error rate (BER) is the correct answer because it is a test equipment that provides a bit error detection system. It is used to determine the quality of received data after it has traveled over a communications link. The BER measures the ratio of the number of bits received in error to the total number of bits transmitted, giving an indication of the data transmission performance. The other options, Megger, Multimeter, and Oscilloscope, are not specifically designed for bit error detection and do not provide the same functionality as a BER test equipment.Rate this question:
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- 10.
(005) A type of pulse modulation (PM) that changes the amplitude of the pulse train to vary according to the amplitude of the input signal is called
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Pulse width modulation (PWM).
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Pulse position modulation.
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Pulse duration modulation.
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Pulse amplitude modulation.
Correct Answer
A. Pulse amplitude modulation.Explanation
Pulse amplitude modulation (PAM) is a type of pulse modulation where the amplitude of the pulse train is varied according to the amplitude of the input signal. This means that the height or intensity of the pulses in the pulse train is changed to represent the varying amplitude of the input signal. This allows for the transmission of analog signals over a digital communication system.Rate this question:
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- 11.
(010) What is used to extend the distance of a fiber optic communication systems link?
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Receiver.
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Transmitter.
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Repeater.
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Patch cords.
Correct Answer
A. Repeater.Explanation
A repeater is used to extend the distance of a fiber optic communication system's link. A repeater receives the optical signal, amplifies it, and then retransmits it to continue the signal transmission over longer distances. This helps to overcome the signal loss that occurs in fiber optic cables over long distances, ensuring that the signal remains strong and clear throughout the entire communication link.Rate this question:
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- 12.
(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 of the Fluke 8025A locks the measurement into the display for viewing and automatically updates the display when a new measurement is taken. This feature allows the user to capture and hold a measurement on the screen without it disappearing or changing until the user releases the button. It is a convenient way to freeze the measurement value and ensure accurate readings are easily viewed.Rate this question:
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- 13.
(012) What initial nuclear radiation elements generate electromagnetic pulses?
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Gamma rays and neutrons.
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Thermally generated x-rays.
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Transient radiation effects on electronics.
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Neutrons and thermally generated X-rays.
Correct Answer
A. Gamma rays and neutrons.Explanation
Gamma rays and neutrons are the initial nuclear radiation elements that generate electromagnetic pulses. Gamma rays are high-energy photons that are emitted during nuclear reactions, while neutrons are neutral subatomic particles that are also released during nuclear reactions. Both gamma rays and neutrons have the ability to generate electromagnetic pulses, which can disrupt electronic devices and systems.Rate this question:
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- 14.
(015) What Air Force program is used to resolve an electromagnetic interference (EMI) incident?
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Mishap prevention.
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Frequency management (FM).
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Electrostatic discharge (ESD) control.
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Spectrum interference resolution (SIR).
Correct Answer
A. Spectrum interference resolution (SIR).Explanation
Spectrum interference resolution (SIR) is the correct answer because it is the Air Force program used to resolve an electromagnetic interference (EMI) incident. This program is specifically designed to identify and mitigate any interference that may occur within the electromagnetic spectrum. It focuses on resolving issues related to frequency management and ensuring that the spectrum is effectively utilized without any interference.Rate this question:
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- 15.
(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 continunous 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 continunous audible tone.Explanation
When testing a diode with the 8025A, if the leads are placed across a "good" diode in one direction, it will produce an "OL" (open) on the display, indicating that the diode is not conducting in this direction. However, when the leads are reversed, a continuous audible tone is produced. This indicates that the diode is conducting in the reverse direction, allowing current to flow through it.Rate this question:
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- 16.
(020) What area of a digital storage oscilloscope takes digitized samples and performs numberous manipulations on the data including measuring rise and fall times, periods, time intervals, and math 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 correct answer is microprocessors. In a digital storage oscilloscope, the microprocessors are responsible for taking digitized samples from the input signal and performing various manipulations on the data. This includes measuring rise and fall times, periods, time intervals, and math computations. The microprocessors play a crucial role in processing and analyzing the acquired data to provide accurate measurements and visual representations on the oscilloscope's display.Rate this question:
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- 17.
(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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9,600 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 appropriate bit rate to use for a bit error rate test on a 64 Kbps data circuit. Bit error rate testing is used to measure the number of errors that occur in a data transmission, and it is important to use the same bit rate as the circuit being tested in order to accurately assess the error rate. Therefore, using a bit rate of 64 Kbps for a 64 Kbps data circuit ensures that the test is conducted at the correct speed and provides accurate results.Rate this question:
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- 18.
(001) What reason for modulation involves modulating 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 improves the ease of radiation. This means that it is easier to transmit the modulated signals over long distances without significant loss or degradation. Modulation allows for the efficient use of the available bandwidth and helps to overcome the limitations of long-distance transmission, such as signal attenuation and interference. By modulating the low frequency signals, they can be easily transmitted and received over long distances, ensuring effective communication.Rate this question:
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- 19.
(002) If the modulating audio signal is 10kHz wide, what is the bandwidth of the transmitted amplitude modulated signal?
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5 kHz
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10 kHz
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15 kHz
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20 kHz
Correct Answer
A. 20 kHzExplanation
The bandwidth of an amplitude modulated signal is determined by the sum of the highest frequency in the modulating signal and the highest frequency in the carrier signal. In this case, the modulating audio signal is 10 kHz wide, so the highest frequency in the modulating signal is 10 kHz. Assuming the carrier signal has a frequency of 0 Hz, the bandwidth of the transmitted amplitude modulated signal would be 10 kHz + 0 Hz = 10 kHz. Therefore, the correct answer is 10 kHz, not 20 kHz as stated in the given answer.Rate this question:
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- 20.
(009) Small current that flows from a photodiode even with no light is called
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Dark current.
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Dispersion.
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Distortion.
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Ionization.
Correct Answer
A. Dark current.Explanation
Dark current refers to the small current that flows through a photodiode even in the absence of light. This current is caused by thermal excitation of charge carriers in the photodiode's semiconductor material. The dark current can affect the accuracy and sensitivity of the photodiode's measurements, as it adds to the signal that is generated when light is present. By understanding and compensating for the dark current, the performance of the photodiode can be optimized.Rate this question:
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- 21.
(014) How can you normally eliminate electromagnetic interference (EMI) noise bursts caused by sodium and mercurt 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. -
- 22.
(033) What operational capability of the communication service monitor produces 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 that produces sine, square, and triangle waveforms is known as a function generator. A function generator is a device that can generate various types of waveforms with specific frequencies and amplitudes. It is commonly used in testing and troubleshooting electronic circuits and communication systems.Rate this question:
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- 23.
(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 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 occupied by the modulated signal is twice the range of frequencies present in the original modulating signal. This is because in amplitude modulation, the sidebands are created above and below the carrier frequency, resulting in the doubling of the bandwidth.Rate this question:
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- 24.
(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 light that has a fixed phase relationship between its waves, meaning that all the waves are in sync and have the same frequency and wavelength. This is different from incoherent light, which has waves that are not in sync and have different frequencies and wavelengths. Ordinary light refers to light from sources like the sun or a light bulb, which can be either coherent or incoherent. Invisible light refers to light that is not visible to the human eye, such as ultraviolet or infrared light.Rate this question:
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- 25.
(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 other electronic devices or environmental factors, rather than being caused by internal issues within the radio itself.Rate this question:
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- 26.
(014) What type of equipment often generates many spurious emissions?
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Slow tuning receiver.
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Rapid tuning receiver.
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Slow tuning transmitter.
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Rapid tuning transmitter.
Correct Answer
A. Rapid tuning transmitter.Explanation
Rapid tuning transmitters often generate many spurious emissions. This is because the rapid tuning process can cause frequency instability and result in unintended emissions at frequencies other than the desired one. Slow tuning receivers and transmitters, on the other hand, are less likely to generate spurious emissions as they have a more stable frequency tuning process.Rate this question:
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- 27.
(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
The abbreviation dBm is commonly used to indicate power levels in a logarithmic scale relative to a 1-milliwatt standard. It represents the ratio of decibels, which is a unit used to express the relative difference between two power levels, in this case, the power level being measured and the 1-milliwatt standard. Therefore, the correct answer is that dBm indicates the ratio of decibels relative to a 1-milliwatt standard.Rate this question:
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- 28.
(007) What error detection method adds stacked characters, divides it by 255, and disregards the answer except for the remainder?
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Checksum.
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Block check character.
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Cyclic redundancy check.
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Vertical redundancy check.
Correct Answer
A. Checksum.Explanation
Checksum is an error detection method that adds stacked characters, divides it by 255, and disregards the answer except for the remainder. It is commonly used in data transmission to detect errors that may occur during the transmission process. By comparing the calculated checksum at the receiving end with the transmitted checksum, any errors can be identified.Rate this question:
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- 29.
(008) Laser diode power coupling is measured in which range
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Megawatt.
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Microwatt.
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Milliwatt.
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Kilowatt.
Correct Answer
A. Milliwatt.Explanation
Laser diode power coupling is measured in the milliwatt range. This is because laser diodes are typically used in applications that require low to moderate power output. Milliwatts are a suitable unit for measuring the power output of laser diodes as they provide a precise measurement within the appropriate range for these devices. Megawatts, kilowatts, and microwatts are not commonly used to measure laser diode power coupling.Rate this question:
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- 30.
(025) What component on a protocol analyzer process the frames based on the selected test and user configuration inputs?
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Counter.
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Buffer.
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Central processing unit (CPU).
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Filter.
Correct Answer
A. Central processing unit (CPU).Explanation
The central processing unit (CPU) on a protocol analyzer is responsible for processing the frames based on the selected test and user configuration inputs. It is the main component that executes instructions and carries out the necessary calculations and operations to analyze the frames. The CPU performs tasks such as filtering, capturing, decoding, and analyzing network traffic, allowing users to monitor and troubleshoot network protocols effectively.Rate this question:
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- 31.
(014) What type of electromagnetic interference (EMI) occurs when a receiver responds to off-frequency signals?
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Rusty Bolt.
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Co-channel.
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Brute force.
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Spurious responses.
Correct Answer
A. Spurious responses.Explanation
Spurious responses refer to electromagnetic interference that occurs when a receiver responds to off-frequency signals. This means that the receiver is picking up signals that are not on the intended frequency, leading to interference and potentially affecting the performance of the receiver.Rate this question:
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- 32.
(014) 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 generate noise on power lines. These disturbances can cause fluctuations in the electrical current flowing through the power lines, resulting in audible noise. This noise can be heard as crackling, buzzing, or humming sounds. Therefore, the correct answer is "Power line."Rate this question:
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- 33.
(029) When reading forward power on a wattmeter, what does two right facing arrow head mean?
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Equipment malfunction.
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Calculating forward power.
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No power is applied for reading.
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Power exceeds 120 percent of the range.
Correct Answer
A. Power exceeds 120 percent of the range.Explanation
The two right facing arrow heads on a wattmeter indicate that the power being measured exceeds 120 percent of the range. This means that the power being measured is higher than what the wattmeter is designed to handle, potentially indicating an overload or equipment malfunction.Rate this question:
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- 34.
(002) When the modulating signal and carrier signal are combined within a modulator, the output signal contains a/an
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Modulating signal, upper sideband, 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 output signal contains the carrier signal, as well as the upper sideband and lower sideband. The carrier signal is the original unmodulated signal, while the upper and lower sidebands are the result of the modulation process.Rate this question:
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- 35.
(007) When using vertical redundancy check (VRC), 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 American Standard code for Information Interchange (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 parity. Parity is a form of error checking where an extra bit is added to the data to ensure that the number of ones in the data is always even or odd. This allows the receiver to detect if there has been an error during transmission by checking the parity bit. If the number of ones in the received data does not match the expected parity, then an error has occurred.Rate this question:
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- 36.
(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
When using forward error control as a method of error correction, error correction takes place at the receiving end. This means that the errors in the transmitted data are detected and corrected at the destination or receiver of the data. The receiver uses the error control mechanism to identify and fix any errors that may have occurred during transmission, ensuring that the received data is accurate and reliable.Rate this question:
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- 37.
(009) What photo detector converts one photon to one electron?
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Light emitting diode (LED).
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Avalanche photodiode.
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Positive intrinsic negative (PIN) diode.
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Integrated photodiode/preamplifier (IDP).
Correct Answer
A. Positive intrinsic negative (PIN) diode.Explanation
A positive intrinsic negative (PIN) diode is a type of photodetector that converts one photon to one electron. This is because the PIN diode has a wide depletion region, allowing it to absorb more photons and generate a larger current. This makes it more sensitive to low light levels and capable of converting individual photons into individual electrons.Rate this question:
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- 38.
(015) What is the first step in the Air Force spectrum interference resolution (SIR) program?
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Identify the source.
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Verifying the source.
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Resolving the interference.
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Reporting the interference.
Correct Answer
A. Identify the source.Explanation
The first step in the Air Force spectrum interference resolution (SIR) program is to identify the source of the interference. This involves determining the origin or location of the interference signal or source that is causing disruption in the spectrum. Once the source is identified, further steps can be taken to verify, resolve, and report the interference.Rate this question:
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- 39.
(015) What do you do when you are reasonably sure electromagnetic interference (EMI) 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 (SIR) office.
Correct Answer
A. Systematically gather data for analysis.Explanation
When you are reasonably sure electromagnetic interference (EMI) exists, the best course of action is to systematically gather data for analysis. This means collecting relevant information and data about the interference, such as its frequency, intensity, and duration. By doing this, you can better understand the nature and source of the interference, which will help in finding a solution or mitigating its effects. Requesting engineering assistance or contacting the base frequency manager or spectrum interference resolution (SIR) office may be necessary later on, but gathering data for analysis is the first step in addressing EMI.Rate this question:
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- 40.
(018) How are voltage, time, and depth represented on the oscilloscope display?
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Voltage = intensity, time = vertical axis, and depth = horizontal axis.
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Voltage = intensity, time = horizontal axis, and depth = vertical axis.
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Voltage = horizontal axis, time = vertical axis, and depth = intensity.
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Voltage = vertical axis, time = horizontal axis, and depth = intensity.
Correct Answer
A. Voltage = vertical axis, time = horizontal axis, and depth = intensity.Explanation
Voltage is represented on the vertical axis of the oscilloscope display, with higher voltages being displayed higher on the axis. Time is represented on the horizontal axis, with the display showing the progression of time from left to right. Depth, in this context, refers to the intensity or brightness of the waveform being displayed, and it is represented by the intensity of the waveform on the screen.Rate this question:
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- 41.
(011) Short sections of single fiber cables that has a connector at each end is called a
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Pigtail.
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Patch cord.
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Jumper.
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Breakout cables.
Correct Answer
A. Patch cord.Explanation
A short section of single fiber cables that has a connector at each end is called a patch cord. A patch cord is used to connect devices or components in a network or telecommunications system. It is often used to connect equipment in a data center or to connect a device to a patch panel. Patch cords are typically used for temporary or semi-permanent connections and can be easily plugged and unplugged. They are available in various lengths and connector types to accommodate different equipment and network configurations.Rate this question:
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- 42.
(032) What test equipment combines the operations of many test instruments in a single compact unit?
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Volt meter.
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Oscilloscope.
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Impedance meter.
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Communication service monitor.
Correct Answer
A. Communication service monitor.Explanation
A communication service monitor combines the operations of many test instruments in a single compact unit. It is designed to perform a wide range of functions such as measuring voltage, current, impedance, and other parameters. It is commonly used in the telecommunications industry for testing and troubleshooting communication systems.Rate this question:
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- 43.
(002) If a carrier frequency of 1 MHz and a modulating tone of 10 kHz goes to the modulator, the output signal includes
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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 inputted into the modulator, the output signal will include the carrier frequency (1 MHz), the sum of the carrier and modulating frequencies (1.01 MHz), and the difference between the carrier and modulating frequencies (0.99 MHz). This is due to the process of modulation, where the modulating signal is used to vary the amplitude, frequency, or phase of the carrier signal.Rate this question:
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- 44.
(010) Which repeater amplifies optical signal without converting to and from the electrical domain?
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Repeaters.
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Regenerators.
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Optical amplifiers.
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Receiver.
Correct Answer
A. Optical amplifiers.Explanation
Optical amplifiers are devices that amplify optical signals without converting them to electrical signals. They use a process called stimulated emission to amplify the signal by adding energy to it. This allows the signal to travel longer distances without degradation. Repeaters, on the other hand, regenerate electrical signals by converting them to optical signals and then back to electrical signals. Regenerators are similar to repeaters but are used for digital signals. Receivers are devices that receive and convert signals from one form to another, such as from optical to electrical.Rate this question:
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- 45.
(012) Atmospheric disturbances from initial nuclear radiation on higher frequencies affect comunications by which types of effects?
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Blackout.
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Absorption.
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Scintillation.
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Attenuation.
Correct Answer
A. Scintillation.Explanation
Atmospheric disturbances caused by initial nuclear radiation can affect communications through scintillation. Scintillation refers to the rapid fluctuations in the intensity and phase of electromagnetic waves as they pass through a turbulent medium, such as the atmosphere. These fluctuations can cause signal fading and distortion, leading to disruptions in communication. Absorption refers to the process of energy being absorbed by a medium, attenuation refers to the gradual decrease in signal strength over distance, and blackout refers to a complete loss of communication. However, in the context of the given question, scintillation is the most relevant effect caused by atmospheric disturbances from initial nuclear radiation.Rate this question:
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- 46.
(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 normally uses real-time sampling on single-shot or seldom-occurring signals. Real-time sampling allows the oscilloscope to capture and display the waveform as it occurs, ensuring accurate representation of the signal. This type of sampling is essential for capturing transient or sporadic signals that may occur infrequently. Sequential sampling would not be suitable as it involves capturing samples in a sequential manner, which may miss important details of the signal. Repetitive sampling is used for repetitive signals, while random sampling is used for random signals.Rate this question:
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- 47.
(006) If an error should occur, what data transmission is lost in a 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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Synchronization (SYNC) bit.
Correct Answer
A. Block of data.Explanation
In synchronous transmission, data is transmitted in blocks. Each block consists of multiple characters. If an error occurs during transmission, it means that one or more characters within the block have been corrupted or lost. Therefore, the correct answer is "Block of data" as the entire block of data is lost in case of an error in synchronous transmission.Rate this question:
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- 48.
(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. -
- 49.
(002) Which statement concerning bandwidth is true?
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Overmodulating increases bandwidth due to the production of harmonics.
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Undermodulating increases bandwidth due to the production of harmonics.
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Overmodulating increases bandwidth due to the output's increased amplitude.
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Undermodulating increases bandwidth due to the output's increased amplitude.
Correct Answer
A. Overmodulating increases bandwidth due to the production of harmonics.Explanation
Overmodulating refers to the process of increasing the amplitude of a signal beyond its normal limits. This causes the signal to produce harmonics, which are additional frequencies that are multiples of the original signal frequency. These harmonics increase the overall bandwidth of the signal. Therefore, overmodulating increases bandwidth due to the production of harmonics.Rate this question:
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Mar 21, 2023Quiz Edited by
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Jul 19, 2011Quiz Created by
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