3d1x2 5 Level CDC Vol. 1

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  • 1/69 Questions

    The information-carrying components that occur on either side of a carrier are called

    • Sidebands.
    • Sine waves.
    • Frequency translators.
    • Modulating fequencies.
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About This Quiz

This quiz, titled '3D1X2 5 level CDC vol. 1', tests knowledge on signal processing techniques such as analog and digital modulation. It covers key concepts like PCM, CVSD modulation, and the characteristics of amplitude modulation, enhancing skills crucial for communications technology professionals.

Signal Processing Quizzes & Trivia

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  • 2. 

    The only basic waveform in nature is a

    • Carrier wave.

    • Pure sine wave.

    • Resultant wave.

    • Composite wave.

    Correct Answer
    A. Pure sine wave.
    Explanation
    A pure sine wave is the only basic waveform in nature because it represents a single frequency with no harmonics or distortion. It is a smooth, continuous waveform that oscillates between positive and negative values in a regular pattern. Other waveforms, such as a composite wave or resultant wave, are formed by combining multiple sine waves of different frequencies and amplitudes. Therefore, the pure sine wave is the most fundamental and natural waveform found in nature.

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  • 3. 

    Three categories of synchronization used in digital data circuits are

    • Synchronous, asynchronous, and isochronous.

    • Isochronous, asynchronous, and bisynchronous.

    • Nonsynchronous, bisynchronous, and synchronous.

    • Asynchronous, bisynchronous, and nonsynchronous.

    Correct Answer
    A. Synchronous, asynchronous, and isochronous.
    Explanation
    The correct answer is synchronous, asynchronous, and isochronous. These three categories of synchronization are commonly used in digital data circuits. Synchronous synchronization refers to a method where data is transmitted in a synchronized manner with a clock signal. Asynchronous synchronization, on the other hand, does not rely on a clock signal and instead uses start and stop bits to indicate the beginning and end of each data packet. Isochronous synchronization is used for real-time data transmission, ensuring a constant and predictable data rate.

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  • 4. 

    If 100 percent modulation is exceeded and there is distortion in the modulating signal, addititonal sidebands are generated. We indentify these sidebands as what?

    • Transmitted intelligence

    • Intensity of speech

    • Composite waves

    • Splatter

    Correct Answer
    A. Splatter
    Explanation
    When the modulating signal exceeds 100 percent modulation and distortion occurs, additional sidebands are generated. These sidebands are known as "splatter". Splatter refers to the unwanted and excessive sidebands that result from distortion in the modulating signal.

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  • 5. 

    What term is associated with the delay or lag introduced in the application of voltage from one section to the next?

    • Latency.

    • Phase delay.

    • Propagation constant.

    • Phase delay distortion.

    Correct Answer
    A. Latency.
    Explanation
    Latency is the term associated with the delay or lag introduced in the application of voltage from one section to the next. It refers to the time it takes for a signal to travel from its source to its destination. In the context of this question, latency is the most appropriate term as it directly relates to the delay in voltage application. The other options, phase delay, propagation constant, and phase delay distortion, are not as directly related to the delay in voltage application as latency is.

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  • 6. 

    When using an ohmmeter to take a resistance reading, what preliminary precaution should you take?

    • Properly seat the test lead into the current input terminal jack.

    • Disconnect the power from the circuit being tested.

    • Place the meter in the frequency mode.

    • Set the range for maximum reading.

    Correct Answer
    A. Disconnect the power from the circuit being tested.
    Explanation
    When using an ohmmeter to take a resistance reading, it is important to disconnect the power from the circuit being tested as a preliminary precaution. This is necessary to ensure safety and prevent any potential damage to the meter or the circuit. By disconnecting the power, you eliminate the risk of electrical shock or short circuits that could occur if the circuit is still energized. It is always recommended to prioritize safety when working with electrical circuits and equipment.

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  • 7. 

    What converts analog signal informaton into an analog carrier signal?

    • Delta modulation (DM)

    • Digital modulation

    • Analog modulation

    • Adaptive modulation

    Correct Answer
    A. Analog modulation
    Explanation
    Analog modulation is the process of converting analog signal information into an analog carrier signal. This involves varying the amplitude, frequency, or phase of the carrier signal in accordance with the input analog signal. By doing so, the information contained in the analog signal can be transmitted over long distances through the carrier signal. This method is commonly used in various communication systems, such as radio and television broadcasting, where the original analog signal needs to be converted into a format suitable for transmission.

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  • 8. 

    In Time Division Multiplexing (TDM), the transmitting multiplexer will put  a bit or byte from each of the incoming lines into a specifically allocated what?

    • Channel

    • Trunk

    • Time slot

    • Port

    Correct Answer
    A. Time slot
    Explanation
    In Time Division Multiplexing (TDM), the transmitting multiplexer will allocate a specific time slot for each bit or byte from the incoming lines. This time slot is where the data from each line is placed before being transmitted. Therefore, the correct answer is "time slot."

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  • 9. 

    Which section of a bit error rate test (BERT) set measures the received test pattern?

    • Transmitter

    • Emitter.

    • Detector.

    • Receiver.

    Correct Answer
    A. Receiver.
    Explanation
    The section of a bit error rate test (BERT) set that measures the received test pattern is the receiver. The receiver is responsible for receiving the transmitted test pattern and analyzing it to determine the number of bit errors that occurred. It compares the received pattern with the expected pattern to calculate the bit error rate, which is a measure of the quality of the transmission. The transmitter is responsible for sending the test pattern, the emitter is not a relevant term in this context, and the detector does not directly measure the received test pattern.

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  • 10. 

    What is the main advantage of differential phase shift keying (DPSK)?

    • Carrier presence is required to detect change

    • It requires a less complex receiver than a basic phase shift keying (PSK) signal

    • It requires a more complex receiver than a basic PSK signal

    • The demodulator needds to detect changes in the absolute phase values

    Correct Answer
    A. It requires a less complex receiver than a basic phase shift keying (PSK) signal
    Explanation
    Differential phase shift keying (DPSK) has the main advantage of requiring a less complex receiver than a basic phase shift keying (PSK) signal. This means that the receiver in a DPSK system can be simpler and more cost-effective compared to a PSK system. In DPSK, the receiver only needs to detect changes in the relative phase values between consecutive symbols, rather than detecting changes in the absolute phase values. This simplifies the receiver design and reduces its complexity, making DPSK a more efficient modulation scheme in terms of receiver implementation.

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  • 11. 

    What unit is most commonly used in data systems to express signaling speed?

    • Baud

    • Baudot

    • Sense interface

    • Bits per second (bps)

    Correct Answer
    A. Bits per second (bps)
    Explanation
    The correct answer is bits per second (bps). Baud is a unit that measures the number of signal changes per second, which is not the same as the number of bits transmitted per second. Baudot is a character encoding scheme, not a unit of measurement. Sense interface is not a commonly used unit for signaling speed in data systems. Therefore, bits per second (bps) is the most commonly used unit to express signaling speed in data systems.

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  • 12. 

    The method of multiplexing the T1 multiplexer uses is

    • Frequency division.

    • Binary division.

    • Pulse division.

    • Time division.

    Correct Answer
    A. Time division.
    Explanation
    The T1 multiplexer uses the method of time division. Time division multiplexing (TDM) is a technique where multiple signals are combined into a single transmission channel by allocating specific time slots to each signal. In the case of T1 multiplexing, it combines multiple voice or data signals into a single T1 line by dividing the available time slots among the signals. This allows for efficient utilization of the transmission medium and enables multiple signals to be transmitted simultaneously.

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  • 13. 

    What are the two major sections of a bit error rate test (BERT) set?

    • Emitter and detector.

    • Emitter and receiver.

    • Transmitter and detector generator.

    • Transmitter and receiver.

    Correct Answer
    A. Transmitter and receiver.
    Explanation
    The two major sections of a bit error rate test (BERT) set are the transmitter and receiver. In a BERT test, the transmitter generates a known test pattern and sends it to the receiver. The receiver then compares the received pattern with the expected pattern to determine the bit error rate. The emitter and detector options are incorrect as they do not accurately represent the components involved in a BERT test.

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  • 14. 

    The upper sideband in a single-sideband suppressed carrier (SSBSC) modulation is eliminated by

    • Filtering.

    • Detection.

    • Compression.

    • Companding.

    Correct Answer
    A. Filtering.
    Explanation
    In a single-sideband suppressed carrier (SSBSC) modulation, the upper sideband is eliminated by filtering. Filtering refers to the process of selectively allowing certain frequencies to pass through while attenuating or blocking others. In the case of SSBSC modulation, a filter is used to remove the upper sideband, leaving only the lower sideband. This is done to conserve bandwidth and improve spectral efficiency. By eliminating the upper sideband through filtering, the transmitted signal can be more efficiently transmitted and received.

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  • 15. 

    Individual pulses within a digital signal are

    • Bits.

    • Bytes.

    • Codes.

    • Blocks.

    Correct Answer
    A. Bits.
    Explanation
    Individual pulses within a digital signal are represented as bits. A bit is the basic unit of information in computing and digital communications. It can have a value of either 0 or 1, representing the two possible states of a digital signal. Bytes, codes, and blocks are larger units of data that are composed of multiple bits. Therefore, bits are the correct answer as they represent the individual pulses within a digital signal.

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  • 16. 

    In what type of signal does the signal level move to one of the discrete signal levels, but returns to the zero level after a predetermined time?

    • Non-return-to-zero (NRZ) level.

    • Non-return-to-zero mark.

    • Non-return-to-zero space.

    • Return-to-zero.

    Correct Answer
    A. Return-to-zero.
    Explanation
    In a return-to-zero signal, the signal level moves to one of the discrete signal levels but returns to the zero level after a predetermined time. This means that the signal alternates between high and low levels, with each level being held for a specific duration before returning to zero. This type of signal is commonly used in digital communication systems to represent binary data, where the presence of a signal level represents a binary "1" and the absence of a signal represents a binary "0".

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  • 17. 

    Any actions we take to protect our forces, facilities, and equipment for electronic action that can destroy or degrade our capabilities is considered

    • Electronic combat.

    • Electronic protection.

    • Electronic attack.

    • Electronic warfare support.

    Correct Answer
    A. Electronic protection.
    Explanation
    Electronic protection refers to the measures taken to safeguard our forces, facilities, and equipment from electronic actions that can harm or weaken our capabilities. This can include implementing security protocols, using encryption techniques, and employing countermeasures to prevent unauthorized access, interference, or disruption of electronic systems. It focuses on defending our electronic infrastructure and ensuring its proper functioning, rather than actively engaging in offensive electronic actions.

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  • 18. 

    Which push-buttons would you select to get 125-ohm (Ω) impedance on the time domain reflectometer?

    • 50Ω, 75Ω, and 125Ω.

    • 75Ω and 125Ω .

    • 50Ω and 125Ω .

    • 50Ω and 75Ω.

    Correct Answer
    A. 50Ω and 75Ω.
    Explanation
    To achieve a 125-ohm impedance on the time domain reflectometer, you would need to select the push-buttons for 50Ω and 75Ω. The impedance is determined by the combination of resistances in the circuit, and selecting these two resistances in parallel would result in a total impedance of 125Ω.

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  • 19. 

    Jamming a portion of the frequency spectrum is an example of

    • Electronic combat.

    • Electronic protection.

    • Electronic attack.

    • Electronic warfare support.

    Correct Answer
    A. Electronic attack.
    Explanation
    Jamming a portion of the frequency spectrum refers to the deliberate interference with electronic signals in order to disrupt, deny, or degrade communication or radar systems. This is a form of electronic attack, as it involves actively disrupting the enemy's electronic capabilities. Electronic combat refers to the broader concept of using electronic means in warfare, which includes electronic attack, electronic protection (defensive measures to protect friendly electronic systems), and electronic warfare support (providing information and intelligence on enemy electronic systems). Therefore, the correct answer is electronic attack.

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  • 20. 

    When is the voltage applied in loop-start signaling?

    • When dial tone is present.

    • On-hook condition.

    • Off-hook condition.

    • During the ringback signal.

    Correct Answer
    A. Off-hook condition.
    Explanation
    Loop-start signaling is a method used in telecommunication systems to establish a connection between two devices. In loop-start signaling, the voltage is applied when the phone is in the off-hook condition. The off-hook condition refers to the state when the phone receiver is lifted or when a call is in progress. This voltage allows the signaling and communication to take place between the two devices. Therefore, the correct answer is off-hook condition.

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  • 21. 

    What is the power that is reflected back to an optical source in the time domain reflectometer (TDR)?

    • Reflection.

    • Backscatter.

    • Scatter coefficient.

    • Reflection coefficient.

    Correct Answer
    A. Backscatter.
    Explanation
    In a time domain reflectometer (TDR), the power that is reflected back to an optical source is referred to as backscatter. Backscatter occurs when some of the incident light is scattered or reflected back towards the source due to changes in the optical properties of the medium it encounters. This can happen when the light encounters variations in the refractive index or physical structure of the medium. The backscattered power can provide valuable information about the characteristics of the medium being measured, such as its composition or any defects present.

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  • 22. 

    What converts analog signal informaton into a digital carrier signal?

    • Delta Modulation (DM)

    • Digital modulation

    • Analog modulation

    • Adaptive modulation

    Correct Answer
    A. Digital modulation
    Explanation
    Digital modulation is the process of converting analog signal information into a digital carrier signal. This is achieved by using techniques such as amplitude shift keying (ASK), frequency shift keying (FSK), or phase shift keying (PSK) to encode the analog signal into a digital format. These modulation techniques allow for efficient transmission and reception of the digital signal, ensuring accurate and reliable communication.

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  • 23. 

    Which statement best describes a binary with eight-zero substitution (B8ZS) signal?

    • The information is transmitted in three different voltage levels.

    • A logic one is transmitted as positive voltage if the previous logic one was negative.

    • The level always returns to zero for 50 percent of the bit cycle after every transition.

    • Bipolar violations are intentionally inserted into a data signal to break up long strings of zeros.

    Correct Answer
    A. Bipolar violations are intentionally inserted into a data signal to break up long strings of zeros.
    Explanation
    B8ZS, or binary with eight-zero substitution, is a line code used in telecommunications to ensure proper synchronization and prevent long strings of zeros. It intentionally inserts bipolar violations into the data signal, which means it alternates between positive and negative voltage levels, to break up consecutive zeros. This helps maintain the integrity of the signal and ensures accurate transmission.

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  • 24. 

    What type of error is the result of two successive logic one pulses of the same polarity in violation of alternate mark inversion coding rules?

    • Cyclic redundancy check.

    • Bipolar violation.

    • Bit slip.

    • Frame.

    Correct Answer
    A. Bipolar violation.
    Explanation
    A bipolar violation is the error that occurs when two successive logic one pulses of the same polarity are transmitted in violation of alternate mark inversion coding rules. In alternate mark inversion coding, logic one pulses are supposed to alternate in polarity to ensure proper synchronization and error detection. When two consecutive logic one pulses of the same polarity are transmitted, it results in a bipolar violation. This violation can cause errors in data transmission and can be detected using techniques like line coding and error detection algorithms like cyclic redundancy check (CRC).

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  • 25. 

    The definition of electronic attack can be found in which publication?

    • Air Force Doctrine Document 2–5.1.

    • Air Force Instruction 10–101.

    • Air Force Policy Memorandum 2–1.

    • Air Force Manual 2–5.1.

    Correct Answer
    A. Air Force Doctrine Document 2–5.1.
    Explanation
    The correct answer is Air Force Doctrine Document 2–5.1. This publication is likely to contain the definition of electronic attack as it is a doctrine document that provides guidance and direction for Air Force operations. It is a comprehensive source of information that outlines the principles, concepts, and procedures for electronic attack, making it the most appropriate publication to find the definition.

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  • 26. 

    What form of modulation is insensitive to signal variations?

    • Delta

    • Frequency shift keying (FSK)

    • Pulse-amplitude modulation (PAM)

    • Binary-phaseshift keying or bi-phase shift keying (BPSK)

    Correct Answer
    A. Binary-phaseshift keying or bi-phase shift keying (BPSK)
    Explanation
    Binary-phaseshift keying or bi-phase shift keying (BPSK) is insensitive to signal variations because it uses two phases to represent the digital data. Each phase represents a different bit value, usually 0 or 1. The phase shift between the two states is 180 degrees, which means that even if there is noise or interference in the signal, the receiver can still distinguish between the two phases and accurately decode the data. This makes BPSK a robust modulation scheme that is commonly used in applications where signal variations are a concern, such as satellite communications and wireless data transmission.

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  • 27. 

    How many bits per character of a 16-step pulse-code modulation (PCM) system are used to describe the quantized analog sample?

    • 3

    • 4

    • 5

    • 8

    Correct Answer
    A. 4
    Explanation
    A 16-step PCM system uses 4 bits per character to describe the quantized analog sample. In PCM, the analog signal is sampled and then quantized into a discrete set of levels. The number of bits per character determines the number of quantization levels that can be represented. In this case, with 4 bits per character, there are 2^4 = 16 quantization levels available, which matches the 16-step PCM system mentioned in the question.

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  • 28. 

    How many bits are in the extended superframe format (ESF) framing sequence?

    • 8

    • 12

    • 24

    • 48

    Correct Answer
    A. 24
    Explanation
    The extended superframe format (ESF) framing sequence consists of 24 bits.

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  • 29. 

    What communications information signal uses a continuous 350- and 440-Hz frequency pair?

    • Dial tone.

    • Ringback signal.

    • Off-hook alert.

    • Call waiting.

    Correct Answer
    A. Dial tone.
    Explanation
    A dial tone is a communications information signal that uses a continuous 350- and 440-Hz frequency pair. It is the sound heard when a telephone line is active and ready for dialing. When a user picks up the phone, they hear the dial tone indicating that they can start dialing a number. The specific frequency pair of 350- and 440-Hz is used to generate this distinct sound.

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  • 30. 

    What communications information signal uses a signal cycled on and off for 0.5 second and contains the generation of a 480- and 620-Hz frequency pair?

    • Dial tone.

    • Busy signal.

    • Off-hook alert.

    • Call waiting.

    Correct Answer
    A. Busy signal.
    Explanation
    A busy signal is a communications information signal that is cycled on and off for 0.5 seconds. It indicates that the line is currently busy and cannot accept another call. The generation of a 480- and 620-Hz frequency pair is a characteristic of the busy signal. This combination of frequencies is used to create the distinct sound of a busy signal.

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  • 31. 

    Bit count integrity problems are  primarily  caused by

    • Impedance mismatch.

    • System timing faults.

    • Improper equipment settings.

    • Changes in atmospheric conditions.

    Correct Answer
    A. System timing faults.
    Explanation
    Bit count integrity problems occur when there are errors or discrepancies in the number of bits being transmitted or received. System timing faults refer to issues in the synchronization of the timing signals between different components or devices in a system. These faults can disrupt the proper timing of data transmission, leading to errors in counting the number of bits. Therefore, system timing faults can be the primary cause of bit count integrity problems.

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  • 32. 

    What communications control signal uses a two-frequency dialing combination?  

    • Pulse dialing.

    • Tone dialing.

    • Digit dialing.

    • Address dialing.

    Correct Answer
    A. Tone dialing.
    Explanation
    Tone dialing is the correct answer because it uses a two-frequency dialing combination. In tone dialing, each number on the telephone keypad corresponds to a specific combination of two frequencies. When a number is dialed, the phone generates these tones, which are then transmitted to the telephone exchange to establish the call. This method is more efficient and faster than pulse dialing, where each digit is represented by a series of pulses. Digit dialing and address dialing are not commonly used terms in telecommunications.

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  • 33. 

    In common associated signaling (CAS), what is the seventh bit in frames 6 and 12 used to convey signaling information known as?

    • Bit robbing.

    • Bit stuffing.

    • Frame correction.

    • Frame enhancement.

    Correct Answer
    A. Bit robbing.
    Explanation
    The seventh bit in frames 6 and 12 in common associated signaling (CAS) is used to convey signaling information known as "bit robbing." Bit robbing refers to the process of stealing one bit from each frame to carry signaling information. This technique allows for the transmission of additional information without requiring extra bits or frames.

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  • 34. 

    Varying the pulse repetition frequency on a radar set is an example of

    • Electronic combat.

    • Electronic attack.

    • Electronic protection.

    • Electronic warfare support.

    Correct Answer
    A. Electronic protection.
    Explanation
    Varying the pulse repetition frequency on a radar set is an example of electronic protection. Electronic protection refers to measures taken to protect electronic systems from electronic attacks. By varying the pulse repetition frequency, the radar set can confuse or deceive potential attackers, making it more difficult for them to accurately detect and track the radar signal. This technique helps to safeguard the radar system and maintain its operational integrity.

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  • 35. 

    The form of pulse modulation in which the pulse is varied within a set range of positoins is known as

    • Pulse-amplitude modulation (PAM).

    • Pulse-duration modulation (PDM).

    • Pulse-positon modulation (PPM).

    • Pulse-code modulation (PCM).

    Correct Answer
    A. Pulse-positon modulation (PPM).
    Explanation
    Pulse-position modulation (PPM) is a form of pulse modulation where the position of the pulse within a set range is varied. In PPM, the timing or position of the pulse represents the information being transmitted. This modulation technique is commonly used in digital communication systems to transmit data over a channel. PAM, PDM, and PCM are different forms of pulse modulation where the amplitude, duration, and code of the pulse, respectively, are varied instead of the position. Therefore, PPM is the correct answer in this case.

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  • 36. 

    Wave-division multiplexing (WDM) creates teh virtual channels for multiplexing them together for transmission by using different

    • Wavelengths or lambas.

    • Wavelengths or gammas.

    • Frequencies or lambdas.

    • Frequencies or gammas.

    Correct Answer
    A. Wavelengths or lambas.
    Explanation
    Wave-division multiplexing (WDM) is a technology that combines multiple optical signals onto a single fiber by using different wavelengths or lambdas. Each wavelength represents a virtual channel, allowing for the transmission of multiple signals simultaneously. The use of different wavelengths ensures that the signals do not interfere with each other and can be easily separated at the receiving end. Therefore, the correct answer is wavelengths or lambdas.

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  • 37. 

    What communications supervisory signal uses a continuous application of direct current voltage for signaling?

    • Record warning.

    • Fast busy signal.

    • Loop-start.

    • E and M.

    Correct Answer
    A. Loop-start.
    Explanation
    Loop-start is the correct answer because it is a communications supervisory signal that uses a continuous application of direct current voltage for signaling. This signaling method is commonly used in telecommunications systems to indicate the start of a call or to supervise the status of the telephone line. The loop-start signal is generated when a circuit loop is closed, allowing the flow of current to indicate the availability of the line for communication.

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  • 38. 

    In what common channel signaling (CCS) mode are the messages relating to signaling between two points conveyed directly interconnecting these signaling points?

    • Associated mode.

    • Nonassociated mode.

    • Quasi-associated mode.

    • Multi-associated mode.

    Correct Answer
    A. Associated mode.
    Explanation
    Associated mode is the correct answer because in this mode, the messages related to signaling between two points are conveyed directly through the interconnection of these signaling points. In other words, the signaling messages are sent directly from one point to another without any intermediate nodes or additional signaling paths. This mode is commonly used in common channel signaling (CCS) systems where a dedicated signaling channel is established between the two points for efficient and direct communication.

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  • 39. 

    Electronic warfare support includes devices such as

    • Anti-radiation missiles and directed energy weapons.

    • Intelligence platforms and noise jamming systems.

    • Radar warning receivers and intelligence systems.

    • Directed energy weapons and radar warning receivers.

    Correct Answer
    A. Radar warning receivers and intelligence systems.
    Explanation
    The correct answer is radar warning receivers and intelligence systems. Electronic warfare support involves the use of radar warning receivers to detect and identify radar signals, providing early warning to the operator. Intelligence systems are also crucial in electronic warfare support as they gather and analyze information about enemy radar systems, helping to develop effective countermeasures. The other options mentioned, such as anti-radiation missiles and directed energy weapons, are not specifically related to electronic warfare support.

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  • 40. 

    We can express the 6-to-1 improvement of the single-sideband suppressed carrier (SSBSC) mopdulation over conventional amplitude modulation (AM) as

    • 2 decibels (dB) of improvement

    • 4 decibels of improvement

    • 6 decibels of improvement

    • 8 decibels of improvement

    Correct Answer
    A. 8 decibels of improvement
    Explanation
    The 6-to-1 improvement of SSBSC modulation over conventional AM means that the SSBSC modulation provides a signal-to-noise ratio (SNR) that is 6 times better than conventional AM. In terms of decibels, a 6-to-1 improvement corresponds to an improvement of 8 decibels. Decibels are a logarithmic unit used to express the ratio between two power levels, and an improvement of 6-to-1 corresponds to an increase of 8 decibels. Therefore, the correct answer is 8 decibels of improvement.

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  • 41. 

    The amount of deviation in a frquency modulation (FM) signal is directly proportinal to the modulating signal's

    • Phase.

    • Amplitude.

    • Frequency.

    • Apmlitude and frequency.

    Correct Answer
    A. Amplitude.
    Explanation
    In frequency modulation (FM), the amount of deviation in the signal is directly proportional to the modulating signal's amplitude. This means that as the amplitude of the modulating signal increases, the frequency of the carrier signal will deviate more. Therefore, the correct answer is amplitude.

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  • 42. 

    The two major types of frame structures are

    • Low speed and high speed

    • High speed and EBCDIC

    • CCITT and low speed

    • EBCDIC and CCITT

    Correct Answer
    A. CCITT and low speed
    Explanation
    The correct answer is CCITT and low speed. CCITT (Comité Consultatif International Téléphonique et Télégraphique) is a standardization body that focuses on telecommunications. Low speed refers to a type of frame structure that operates at a slower data transfer rate. Therefore, CCITT and low speed are the two major types of frame structures mentioned in the question.

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  • 43. 

    The most common wave-division multiplexing (WDM) system uses how many wavelengths?

    • 1

    • 2

    • 3

    • 4

    Correct Answer
    A. 2
    Explanation
    The most common wave-division multiplexing (WDM) system uses 2 wavelengths. WDM is a technology that allows multiple optical signals to be transmitted simultaneously over a single optical fiber by using different wavelengths of light to carry each signal. This increases the capacity of the fiber and allows for more data to be transmitted. Using 2 wavelengths in a WDM system allows for efficient transmission of multiple signals without interference.

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  • 44. 

    Which option is a characteristic of synchronous data operation?

    • Timing pulses are transmitted within the signal stream.

    • Start and stop pulses control data transmission.

    • System timing is not of critical importance.

    • All data bits are the same length in time.

    Correct Answer
    A. All data bits are the same length in time.
    Explanation
    The characteristic of synchronous data operation is that all data bits are the same length in time. This means that each bit of data is transmitted for the same duration, ensuring that the receiver can accurately interpret the information being transmitted. This allows for reliable and efficient data transmission as the receiver can easily synchronize with the sender and decode the data correctly.

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  • 45. 

    In what type of signal is the information contained in the transition, and there is a transition from one state to the other only when a mark bit is sent?

    • Non-return-to-zero (NRZ) level.

    • Non-return-to-zero mark.

    • Non-return-to-zero space.

    • Return-to-zero level.

    Correct Answer
    A. Non-return-to-zero mark.
    Explanation
    In Non-return-to-zero mark (NRZ-M) encoding, the information is contained in the transition from one state to the other only when a mark bit is sent. In this type of signal, a transition from a high to low voltage level represents a mark bit, while the absence of a transition represents a space bit. This encoding scheme is commonly used in digital communication systems to transmit data.

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  • 46. 

    When using a multimeter, which mode should be used if the reading is unreadable due to fluctuations?

    • Range.

    • Frequency.

    • Display hold.

    • Minimum/maximum (MIN/MAX).

    Correct Answer
    A. Display hold.
    Explanation
    When using a multimeter, the display hold mode should be used if the reading is unreadable due to fluctuations. This mode allows the multimeter to freeze the reading on the display, preventing it from constantly changing and making it easier to read. By using the display hold mode, the user can accurately measure and record the value without being affected by any fluctuations in the measurement.

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  • 47. 

    Which statement best describes an alternate mark inversion (AMI) signal?

    • The information is transmitted in three different voltage levels.

    • A logic one is transmitted as positive voltage if the previous logic one was negative.

    • The level always returns to zero for 50 percent of the bit cycle after every transition.

    • Bipolar violations are intentionally inserted into a data signal to break up long strings of zeros.

    Correct Answer
    A. A logic one is transmitted as positive voltage if the previous logic one was negative.
    Explanation
    AMI stands for Alternate Mark Inversion, which is a line code used for transmitting digital signals. In AMI, a logic one is represented by a positive voltage if the previous logic one was negative. This helps in maintaining a balanced signal and prevents the buildup of DC voltage on the line. By alternating the polarity of consecutive logic ones, AMI ensures that the average voltage over time remains close to zero. This technique is commonly used in telecommunications systems to transmit data efficiently and reliably.

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  • 48. 

    Quanitized analog modulation (QAM) is actually

    • Pulse-amplitude modulation (PAM).

    • Pulse-duration modulation (PDM).

    • Less tolerant of noise than frequency modulation (FM).

    • Analog-to-digital conversion

    Correct Answer
    A. Analog-to-digital conversion
    Explanation
    QAM, or Quanitized analog modulation, is a method of converting analog signals into digital signals. It involves dividing the analog signal into multiple levels or states, each representing a specific digital value. This allows for more efficient transmission and storage of the signal. Therefore, the correct answer is analog-to-digital conversion.

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  • 49. 

    What are the two principle weighting characteristics in use with telecommunication circuit noise?

    • Institute of Electronic and Electrical Engineers and CCITT psophometric.

    • Noise analysis and CCITT psophometric.

    • CCITT psophometric and C-message.

    • C-message and noise analysis.

    Correct Answer
    A. CCITT psophometric and C-message.
    Explanation
    CCITT psophometric and C-message are the two principle weighting characteristics used in telecommunication circuit noise. CCITT psophometric is a standardized measurement that evaluates the subjective annoyance caused by noise in telecommunication systems. C-message is a weighting characteristic that takes into account the frequency response of the human ear and is used to measure the overall loudness of speech signals. These weighting characteristics are important in assessing and quantifying the impact of noise in telecommunication circuits.

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Quiz Review Timeline (Updated): Mar 18, 2023 +

Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.

  • Current Version
  • Mar 18, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Nov 03, 2011
    Quiz Created by
    Woodjh
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