# 3c251 CDC Ure's Set 2

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Quizzes Created: 1 | Total Attempts: 93
Questions: 124 | Attempts: 93

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• 1.

### What is an example of analog to digital and digital to analog techniques

• A.

Amplitude modulation (AM) and frequency modulation (FM).

• B.

Pulse code modulation (PCM) and frequency shift key (FSK).

• C.

Phase modulation (PCM) and quadrature phase shift key (QPSK).

• D.

Pulse code modulation (PCM) and continuously variable slope delta (CVSD) modulation.

D. Pulse code modulation (PCM) and continuously variable slope delta (CVSD) modulation.
Explanation
Pulse code modulation (PCM) is an example of analog to digital (A/D) technique, where an analog signal is converted into a digital signal by sampling and quantizing the amplitude of the signal at regular intervals. Continuously variable slope delta (CVSD) modulation, on the other hand, is an example of digital to analog (D/A) technique, where a digital signal is converted back into an analog signal by reconstructing the original waveform using a continuous variable slope technique. Therefore, PCM and CVSD modulation represent both A/D and D/A techniques.

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• 2.

### What modulation technique is a complete digitization process since it converts an analog signal into one that is discrete with respect to both time and amplitude (or polarity)?

• A.

Pulse-amplitude modulation (PAM).

• B.

Pulse-duration modulation (PMD).

• C.

Pulse-width modulation (PWM).

• D.

Pulse-code modulation (PCM).

D. Pulse-code modulation (PCM).
Explanation
Pulse-code modulation (PCM) is a complete digitization process because it converts an analog signal into a discrete signal in both time and amplitude. PCM samples the analog signal at regular intervals and assigns a binary code to each sample, representing its amplitude. This binary representation allows for accurate reproduction of the original analog signal. In PCM, the time and amplitude of the signal are both quantized, resulting in a fully digitized signal.

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• 3.

### Amplitude modulation (AM) requires a bandwidth that is

• A.

Twice that of the modulating signal.

• B.

Half that of the modulating signal

• C.

Twice that of the carrier signal

• D.

Half that of the carrier signal.

A. Twice that of the modulating signal.
Explanation
Amplitude modulation (AM) requires a bandwidth that is twice that of the modulating signal because in AM, the amplitude of the carrier signal is varied in proportion to the modulating signal. This variation in amplitude results in sidebands being created around the carrier frequency, which contain the modulating signal information. The bandwidth required to transmit these sidebands is directly related to the frequency range of the modulating signal, hence it needs to be twice the frequency range of the modulating signal.

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• 4.

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

• A.

2 decibels (dB) of improvement

• B.

4 dB of improvement

• C.

6 dB of improvement

• D.

8 dB of improvement

D. 8 dB of improvement
Explanation
The 6-to-1 improvement of the single-sideband suppressed carrier (SSBSC) modulation over conventional amplitude modulation (AM) can be expressed as 8 dB of improvement.

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• 5.

### A modulation waveform that contains a carrier plus two sidebands for each modulation frequency is a description of

• A.

A phase modulation (PM)

• B.

A pulse modulation

• C.

A frequency modulation (FM)

• D.

An amplitude modulation (AM)

D. An amplitude modulation (AM)
Explanation
An amplitude modulation (AM) is a modulation waveform that contains a carrier plus two sidebands for each modulation frequency. In AM, the amplitude of the carrier signal is varied in proportion to the instantaneous amplitude of the modulating signal. This results in the carrier signal being modulated to produce two sidebands, one above and one below the carrier frequency. Therefore, an AM waveform contains a carrier plus two sidebands for each modulation frequency.

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• 6.

### If 100 percent modulation is exceeded and there is distortion in the modulating signal, additional sidebands are generated. We identify these sidebands as

• A.

Transmitted intelligence

• B.

Intensity of speech

• C.

Composite waves

• D.

Splatter

D. Splatter
Explanation
When the modulation signal exceeds 100% and distortion occurs, additional sidebands are generated. These sidebands are known as "splatter." Splatter refers to unwanted and excessive sidebands that can cause interference and distortion in the transmitted signal. It is a result of improper modulation and can negatively impact the quality and clarity of the transmitted intelligence or speech.

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• 7.

### To prevent frequency modulation (FM) radio stations from interfering with each other, the Federal Communications Commission (FCC) has set limits that allow each station to cause its oscillator frequency to deviate no more than

• A.

20 kHz

• B.

50 kHz

• C.

75 kHz

• D.

88 kHz

C. 75 kHz
Explanation
The Federal Communications Commission (FCC) has set limits on the amount of frequency deviation allowed for each FM radio station to prevent interference with other stations. In this case, the correct answer is 75 kHz, which means that each station is allowed to cause its oscillator frequency to deviate by a maximum of 75 kHz. This limit ensures that the stations can operate without causing significant interference to neighboring stations, allowing for clear and reliable radio broadcasts.

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• 8.

### The amount of phase shift in a phase modulation (PM) signal is directly proportional to the

• A.

Modulation index

• B.

Rate of phase shift

• C.

Frequency of the modulating signal

• D.

Amplitude of the modulating signal

D. Amplitude of the modulating signal
Explanation
The amount of phase shift in a phase modulation (PM) signal is directly proportional to the amplitude of the modulating signal. This means that as the amplitude of the modulating signal increases, the phase shift in the PM signal also increases. Phase modulation is a type of modulation where the phase of the carrier signal is varied in accordance with the modulating signal. The amplitude of the modulating signal determines the extent to which the phase of the carrier signal is shifted, resulting in a change in the phase of the PM signal.

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• 9.

### quadrature-phase shift keying (QSPK) requires

• A.

Half the bandwidth as does bi-phase shift keying (BPSK)

• B.

The same bandwidth as does BPSK

• C.

Twice the bandwidth as does BPSK

• D.

Four times the bandwidth as does BPSK

A. Half the bandwidth as does bi-phase shift keying (BPSK)
Explanation
Quadrature-phase shift keying (QPSK) is a modulation scheme that uses four different phase shifts to represent data. Each phase shift represents two bits of information. On the other hand, bi-phase shift keying (BPSK) uses only two different phase shifts to represent data, with each phase shift representing one bit of information. Since QPSK can represent twice as much information per symbol compared to BPSK, it requires half the bandwidth to transmit the same amount of data. Therefore, the correct answer is "half the bandwidth as does bi-phase shift keying (BPSK)."

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• 10.

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

• A.

Carrier presence is required to detect changes

• B.

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

• C.

It requires a more complex receiver than a basic PSK signal

• D.

The demodulator needs to detect changes in absolute phase values.

B. 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 DPSK can be implemented with simpler and more cost-effective receiver circuits, making it a practical choice for communication systems. Unlike basic PSK, DPSK does not require the receiver to detect changes in absolute phase values, which reduces complexity and improves efficiency.

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• 11.

### All of these are considered analog modulation techniques except

• A.

Pulse-amplitude modulation (PAM)

• B.

Pulse-duration modulation (PDM)

• C.

Pulse-position modulation (PPM)

• D.

Pulse-code modulation (PCM)

D. Pulse-code modulation (PCM)
Explanation
Pulse-code modulation (PCM) is a digital modulation technique that converts analog signals into a digital format. It samples the amplitude of the analog signal at regular intervals and quantizes each sample into a binary code. On the other hand, pulse-amplitude modulation (PAM), pulse-duration modulation (PDM), and pulse-position modulation (PPM) are all analog modulation techniques that modify the amplitude, duration, or position of pulses to carry information. Therefore, pulse-code modulation (PCM) is the only option that does not fall under the category of analog modulation techniques.

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• 12.

### The form of pulse modulation that requires the pulse width to be varied to convey intelligence is

• A.

Pulse-amplitude modulation (PAM)

• B.

Pulse-duration modulation (PDM)

• C.

Pulse-position modulation (PPM)

• D.

Pulse-code modulation (PCM)

B. Pulse-duration modulation (PDM)
Explanation
Pulse-duration modulation (PDM) is a form of pulse modulation where the pulse width is varied to convey intelligence. In PDM, the duration of the pulse represents the amplitude of the signal being transmitted. By varying the width of the pulses, different levels of the signal can be represented, allowing for the transmission of analog information. This is different from pulse-amplitude modulation (PAM), where the amplitude of the pulse is varied, and pulse-position modulation (PPM), where the position of the pulse within a fixed time interval is varied. Pulse-code modulation (PCM) is a digital modulation technique where the analog signal is sampled and quantized into a binary code.

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• 13.

### Quantized analog modulation is actually

• A.

Pulse-amplitude modulation (PAM)

• B.

Pulse-duration modulation (PDM)

• C.

Less tolerant of noise than frequency modulation (FM)

• D.

Analog-to-digital conversion

D. Analog-to-digital conversion
Explanation
Quantized analog modulation refers to the process of converting analog signals into digital signals. This involves dividing the continuous analog signal into discrete levels or steps, which are then represented by digital values. This conversion allows for more efficient transmission and storage of the signal, as digital signals are less susceptible to noise and interference compared to analog signals. Therefore, quantized analog modulation is essentially analog-to-digital conversion.

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• 14.

### Which type of pulse modulation is least affected by noise?

• A.

Pulse-amplitude modulation (PAM)

• B.

Pulse-duration modulation (PDM)

• C.

Pulse-position modulation (PPM)

• D.

Pulse-code modulation (PCM)

D. Pulse-code modulation (PCM)
Explanation
Pulse-code modulation (PCM) is the least affected by noise compared to other types of pulse modulation. PCM converts analog signals into a digital format by sampling the amplitude of the signal at regular intervals and then quantizing and encoding it into binary code. This digital representation of the signal is more robust against noise interference because it can be accurately reconstructed at the receiver by decoding the binary code. Unlike other types of pulse modulation, PCM does not rely on the amplitude, duration, or position of the pulse, making it less susceptible to noise distortions.

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• 15.

### pulse-code modulation (PCM) code words are assigned to each sample and correspond to its

• A.

Phase

• B.

Time slot

• C.

Amplitude

• D.

Frequency

C. Amplitude
Explanation
In pulse-code modulation (PCM), code words are assigned to each sample, representing their amplitude. This means that the PCM system quantizes the amplitude of the analog signal into discrete levels and assigns a code word to each level. The code words are then used to reconstruct the original analog signal during decoding. The phase, time slot, and frequency are not directly related to the assignment of code words in PCM.

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• 16.

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

• A.

3

• B.

4

• C.

5

• D.

8

B. 4
Explanation
In a 16-step PCM system, there are 16 possible quantized analog samples. To describe these samples, 4 bits per character are used. Each bit can represent 2 possible values (0 or 1), so with 4 bits, there are a total of 2^4 = 16 possible combinations, which matches the number of quantized samples in the system. Therefore, 4 bits per character are used to describe the quantized analog sample in a 16-step PCM system.

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• 17.

### The process of coding pulse code modulation (PCM) quantized pulses to make them a constant duration and amplitude is

• A.

Encoding

• B.

Companding

• C.

Uniform quantizing

• D.

Nonuniform quantizing

A. Encoding
Explanation
The process of coding pulse code modulation (PCM) quantized pulses to make them a constant duration and amplitude is called encoding.

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• 18.

### noise in delta modulation (DM) can be reduced by varying the approximation signal step size in accordance with the input signalâ€™s

• A.

Speed

• B.

Phase

• C.

Amplitude

• D.

Frequency

C. Amplitude
Explanation
In delta modulation (DM), noise can be reduced by varying the approximation signal step size in accordance with the input signal's amplitude. By adjusting the step size based on the amplitude of the input signal, the delta modulation system can better track the changes in the signal and reduce the error or noise introduced during the approximation process. This allows for a more accurate representation of the original signal and improves the overall quality of the delta modulation system.

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• 19.

### What modulation technique varies the step size in accordance with the magnitude of the input signalâ€™s amplitude?

• A.

Delta modulation (DM)

• B.

Frequency modulation (FM)

• C.

Pulse-code modulation (PCM)

• D.

Continuous variable slope delta modulation (CVSD)

D. Continuous variable slope delta modulation (CVSD)
Explanation
Continuous variable slope delta modulation (CVSD) is a modulation technique that varies the step size in accordance with the magnitude of the input signal's amplitude. This means that as the input signal's amplitude increases, the step size also increases, allowing for a more accurate representation of the signal. CVSD is commonly used in applications where high-quality audio transmission is required, such as in telecommunications and voice recording systems.

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• 20.

### Continuous variable slope delta (CVSD) modulation circuitry includes a pulse-amplitude modulator and a

• A.

Low-pass filter

• B.

High- pass filter

• C.

Bandpass filter

• D.

Band-reject filter

C. Bandpass filter
Explanation
CVSD modulation is a technique used to encode analog signals into digital form. It works by continuously varying the slope of the signal waveform. In order to achieve this, a bandpass filter is used in the CVSD modulation circuitry. A bandpass filter allows only a specific range of frequencies to pass through while attenuating frequencies outside of that range. This is important for maintaining the integrity of the analog signal during the modulation process. Therefore, a bandpass filter is the correct choice for the CVSD modulation circuitry.

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• 21.

### Which modulation technique was developed to reduce signal loss and noise in a tactical environment?

• A.

Delta modulation (DM)

• B.

Pulse-code modulation (PCM)

• C.

Conditioned diphase interface modulation (CDI)

• D.

A. Delta modulation (DM)
Explanation
Delta modulation (DM) was developed to reduce signal loss and noise in a tactical environment. This modulation technique samples the difference between the input signal and the quantized version of the previous sample, resulting in a stream of pulses that represent the changes in the signal. By only transmitting the changes in the signal, DM reduces the amount of information that needs to be transmitted, minimizing the impact of signal loss and noise in a tactical environment.

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• 22.

### Up to what percent of speech is redundant?

• A.

35

• B.

45

• C.

65

• D.

75

D. 75
Explanation
Redundancy in speech refers to the repetition or inclusion of unnecessary information. The correct answer is 75 because it suggests that 75% of speech is redundant, meaning that a significant portion of spoken language contains unnecessary or repetitive elements. This emphasizes the importance of concise and efficient communication to avoid redundancy and ensure clear and effective speech.

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• 23.

### The accepted standard for the voice frequency band is

• A.

300 to 1,600 hertz (Hz)

• B.

300 to 2,600 Hz

• C.

300 to 3,400 Hz

• D.

300 to 3,800 Hz

C. 300 to 3,400 Hz
Explanation
The accepted standard for the voice frequency band is 300 to 3,400 Hz. This range encompasses the frequencies at which human voices typically produce sound. Frequencies below 300 Hz are generally considered to be in the lower range and may be associated with deeper voices or certain musical instruments. Frequencies above 3,400 Hz are in the higher range and may include higher pitched voices or certain sound effects. Therefore, the range of 300 to 3,400 Hz covers the majority of frequencies at which human voices are heard.

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• 24.

### Noise may be introduced into speech signals by thermal agitation and

• A.

Power variations

• B.

Amplitude variations

• C.

• D.

Molecular breakdown of electronic components

Explanation
Black body radiation refers to the electromagnetic radiation emitted by an object due to its temperature. In the context of speech signals, black body radiation can introduce noise by causing random fluctuations in the signal. This noise can affect the amplitude and power of the speech signal, leading to variations and distortions. Therefore, black body radiation is a possible source of noise in speech signals.

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• 25.

### Bits taken from an input channel data stream at a rate at least twice the highest frequency appearing in the intelligence signal we call

• A.

The sampling rate

• B.

Pulse-bit stuffing

• C.

Pulse-code modulation

• D.

Elastic storage implementation

A. The sampling rate
Explanation
The correct answer is "the sampling rate". This refers to the rate at which bits are taken from an input channel data stream. It should be at least twice the highest frequency appearing in the intelligence signal to ensure accurate representation of the signal. This is necessary for various processes such as pulse-bit stuffing, pulse-code modulation, and elastic storage implementation.

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• 26.

### Which of these sampling rates is correct for a time division multiplexing (TMD) channel if the highest frequency appearing in the channel is 4 kilohertz (kHz)

• A.

4 kHz

• B.

8 kHz

• C.

12 kHz

• D.

16 kHz

B. 8 kHz
Explanation
The correct answer is 8 kHz because according to the Nyquist-Shannon sampling theorem, the sampling rate should be at least twice the highest frequency in order to accurately reconstruct the original signal. Since the highest frequency in the TMD channel is 4 kHz, the minimum sampling rate required would be 8 kHz.

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• 27.

### Having marker pulses at the beginning of each frame of time-division multiplexing (TDM) signal is one method of

• A.

Encryption

• B.

Synchronization

• C.

Sampling the signal

• D.

Decreasing bandwidth required

B. Synchronization
Explanation
Marker pulses at the beginning of each frame of time-division multiplexing (TDM) signal are used for synchronization. These marker pulses help to align and synchronize the different channels within the TDM signal, ensuring that each channel starts and ends at the correct time. By using marker pulses, the receiver can accurately identify the boundaries of each channel and extract the correct data from the TDM signal. Therefore, synchronization is the correct answer in this case.

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• 28.

### What modulation format is usually used with time slot interchange (TSI)?

• A.

Phase modulation (PM)

• B.

Pulse code modulation (PCM)

• C.

Pulse-duration modulation (PDM)

• D.

Pulse-amplitude modulation (PAM)

B. Pulse code modulation (PCM)
Explanation
TSI is a technique used in digital communication systems to rearrange the order of time slots in a signal. Pulse code modulation (PCM) is a digital modulation format that converts analog signals into digital signals by encoding the amplitude of the analog signal at regular intervals. PCM is commonly used with TSI because it allows for the efficient transmission and manipulation of digital signals, making it suitable for rearranging time slots in a communication system.

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• 29.

### How are incoming and outgoing channels connected within the time slot interchange?

• A.

By physical channel

• B.

By a switch matrix

• C.

By circuit identifier

• D.

By time

D. By time
Explanation
The incoming and outgoing channels within the time slot interchange are connected based on time. This means that the channels are allocated specific time slots within the interchange, and the data from the incoming channels is transmitted during their respective time slots to the outgoing channels. This time-based connection allows for efficient and organized data transfer between channels within the interchange.

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• 30.

### How are channels connected in space division multiplexing?

• A.

By virtual channel

• B.

By switch matrix

• C.

By circuit identifier

• D.

By time

B. By switch matrix
Explanation
Space division multiplexing is a technique used to transmit multiple signals simultaneously by allocating different physical channels in space. In this method, channels are connected by a switch matrix, which is a network of switches that allows the signals from different channels to be routed to their respective destinations. The switch matrix ensures that each signal is directed to the correct channel, enabling the transmission of multiple signals simultaneously.

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• 31.

### Which multiplex scheme periodically redefines the length of its frames?

• A.

Asynchronous time division multiplexing (TDM)

• B.

Frequency data multiplexing (FDM)

• C.

Synchronous TDM

• D.

Isochronous TDM

A. Asynchronous time division multiplexing (TDM)
Explanation
Asynchronous time division multiplexing (TDM) is the multiplex scheme that periodically redefines the length of its frames. In this scheme, each input signal is divided into time slots of fixed length, but the length of the frames can vary. This allows for more efficient use of the available bandwidth as the length of the frames can be adjusted based on the amount of data being transmitted. This is different from synchronous TDM, where the length of the frames remains constant. FDM and isochronous TDM do not redefine the length of their frames.

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• 32.

### In pulse-code modulation (PCM) systems, synchronizing bits may be inserted

• A.

Only at the beginning of a frame

• B.

Only at the end of a frame

• C.

Throughout a frame

• D.

Between frames

C. Throughout a frame
Explanation
In pulse-code modulation (PCM) systems, synchronizing bits are inserted throughout a frame. This is done to ensure that the sender and receiver are in sync and can accurately interpret the transmitted data. By inserting synchronizing bits at regular intervals within the frame, the receiver can easily identify the start and end of each sample within the frame, allowing for accurate decoding of the PCM signal.

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• 33.

### Which type of time-division multiplexing (TDM) synchronization recovers clock from the traffic signal?

• A.

Asynchronous

• B.

isochronous

• C.

Synchronous

• D.

Pulse stuffing

A. Asynchronous
Explanation
Asynchronous time-division multiplexing (TDM) does not require a clock signal to synchronize the transmission of data. Instead, each channel is allowed to transmit data at its own pace, and the receiver extracts the data based on start and stop bits. Therefore, asynchronous TDM does not recover the clock from the traffic signal.

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• 34.

### In a synchronous system, performance of all operations is controlled by a

• A.

Step pulse

• B.

Master clock

• C.

Start-stop pulse

• D.

Synchronization pulse

B. Master clock
Explanation
In a synchronous system, the performance of all operations is controlled by a master clock. The master clock serves as the central timing reference for all components in the system, ensuring that they operate in sync and at the correct timing intervals. It provides a consistent and reliable timing signal that coordinates the execution of various tasks and operations within the system. This allows for precise coordination and synchronization of actions, ensuring smooth and efficient operation of the system as a whole.

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• 35.

### a synchronizing technique used to overcome propagation delay in time-division

• A.

Isochronous

• B.

Master clock

• C.

Pulse stuffing

• D.

Synchronization pulse

C. Pulse stuffing
Explanation
Pulse stuffing is a synchronizing technique used to overcome propagation delay in time-division. It involves inserting extra pulses into the data stream to ensure that the receiving device stays synchronized with the transmitting device, compensating for any delays in the propagation of the signal. This technique helps to maintain the timing and accuracy of the data transmission, ensuring that it is synchronized and aligned properly.

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• 36.

### which module transfers data between the local AN/FCC-100(V) 9 operation and communicates with all the other AN.FCC-100(V) 9 modules and subassemblies

• A.

Processor module

• B.

Aggregate module

• C.

Port carrier module

• D.

Interface module

A. Processor module
Explanation
The processor module is responsible for transferring data between the local AN/FCC-100(V) 9 operation and communicating with all the other AN.FCC-100(V) 9 modules and subassemblies. It acts as the central processing unit and controls the flow of information within the system.

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• 37.

### which module supervises AN/FCC-100(V) 9 internal high-speed bus and the transmission path to the remote AN/FCC-100(V) 9 unit

• A.

Multiplexer/ demultiplexer (mux/demux) module

• B.

Aggregate module

• C.

Port carrier module

• D.

Interface module

B. Aggregate module
Explanation
The correct answer is the Aggregate module. The Aggregate module is responsible for supervising the internal high-speed bus and the transmission path to the remote unit. It is likely that this module is responsible for aggregating and managing data from multiple sources before transmitting it to the remote unit.

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• 38.

### which module provides the interface and termination capability for two pieces of data terminal equipment (DTE) and is designed to accept four plug-in sub modules which interface the DTE

• A.

Processor module

• B.

Aggregate module

• C.

Port carrier module

• D.

Interface module

C. Port carrier module
Explanation
The port carrier module provides the interface and termination capability for two pieces of data terminal equipment (DTE). It is designed to accept four plug-in sub modules that interface the DTE.

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• 39.

### which module is the communication link between the AN/FCC-100(V) 9 and the operatorâ€™s panel or an external control terminal

• A.

Processor module

• B.

Aggregate module

• C.

Port carrier module

• D.

Interface module

D. Interface module
Explanation
The correct answer is the interface module. The interface module serves as the communication link between the AN/FCC-100(V) 9 and the operator's panel or an external control terminal. It allows for the exchange of information and commands between these components, facilitating the control and operation of the system.

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• 40.

### wave-division multiplexing (WDM) creates the virtual channels for multiplexing them together for transmission by using different

• A.

Wavelengths or lambdas

• B.

Wavelengths or gammas

• C.

Frequencies or lambdas

• D.

Frequencies or gammas

A. Wavelengths or lambdas
Explanation
Wave-division multiplexing (WDM) is a technique used to combine multiple optical signals onto a single optical fiber by assigning each signal a different wavelength or lambda. This allows for the transmission of multiple virtual channels simultaneously. The correct answer states that WDM creates the virtual channels for multiplexing by using different wavelengths or lambdas. This is accurate as WDM utilizes different wavelengths or lambdas to separate and combine the signals, enabling efficient and high-capacity transmission over a single fiber.

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• 41.

### what wave-division multiplexing (WDM) technology sends a large number of optical signals closely together

• A.

WMD

• B.

coarse wave division multiplexing (CWDM)

• C.

Dense wave division multiplexing (DWDM)

• D.

Long wave division multiplexing (LDWDM)

C. Dense wave division multiplexing (DWDM)
Explanation
DWDM technology sends a large number of optical signals closely together.

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• 42.

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

• A.

Baud

• B.

Baudot

• C.

Sense interface

• D.

Bits per second

D. Bits per second
Explanation
The most commonly used unit in data systems to express signaling speed is bits per second. This unit measures the number of bits that can be transmitted or processed in one second. Baud is a unit that measures the number of signal changes per second, while Baudot is a character encoding scheme. Sense interface is not a unit of measurement for signaling speed.

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• 43.

### bit count integrity problems are primarily caused by

• A.

Impedance mismatch

• B.

System timing faults

• C.

Improper equipment settings

• D.

Changes in atmospheric conditions

C. Improper equipment settings
Explanation
Bit count integrity problems are primarily caused by improper equipment settings. When the equipment settings are not configured correctly, it can lead to errors in counting the number of bits transmitted or received. This can result in data corruption and integrity issues. It is important to ensure that the equipment settings are properly configured to maintain the accuracy and integrity of the bit count.

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• 44.

### three categories of synchronization used in digital data circuits are

• A.

Impedance mismatch

• B.

System timing faults

• C.

Improper equipment settings

• D.

Changes in atmospheric conditions

A. Impedance mismatch
Explanation
Impedance mismatch refers to a situation where the impedance of the sending and receiving devices in a digital data circuit do not match. This can result in signal reflections and distortions, leading to errors in data transmission. It is one of the three categories of synchronization issues that can occur in digital data circuits, along with system timing faults and improper equipment settings. Changes in atmospheric conditions, on the other hand, are not directly related to synchronization in digital data circuits.

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• 45.

### in synchronous data operation

• A.

Timing pulses are transmitted within the signal stream

• B.

Start and stop pulses control data transmission

• C.

System timing is not of critical importance

• D.

All data bits are the same length in timing

D. All data bits are the same length in timing
Explanation
In synchronous data operation, all data bits are the same length in timing. This means that each bit of data is transmitted within a fixed and consistent time frame. This ensures that the receiving end can accurately interpret and decode the data. Having all data bits of the same length in timing allows for efficient and reliable communication between devices.

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• 46.

### a digital signal that contains synchronizing bits within the signal stream describes

• A.

Synchronous operation

• B.

Asynchronous operation

• C.

Synchronous and /or isochronous operation

• D.

Asynchronous and/or synchronous operation

B. Asynchronous operation
Explanation
A digital signal that contains synchronizing bits within the signal stream describes asynchronous operation. In asynchronous operation, the sender and receiver do not share a common clock signal, and instead rely on start and stop bits to synchronize the transmission. The presence of synchronizing bits within the signal stream indicates that the transmission is asynchronous, as it includes additional information to ensure proper synchronization between sender and receiver.

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• 47.

### in communications, what is essential for continuous error-free performance?

• A.

Strong signal

• B.

Good timing

• C.

Standardized signal format

• D.

Error correction software

B. Good timing
Explanation
Good timing is essential for continuous error-free performance in communications. Timing refers to the synchronization of signals and data transmission, ensuring that information is transmitted and received at the correct time. Without proper timing, signals may be received or transmitted incorrectly, leading to errors in communication. Therefore, having good timing is crucial for maintaining a reliable and error-free communication system.

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• 48.

### while timing ensures the equipment is sending and receiving bits at the same time intervals, synchronization ensures that the

• A.

Receive equipment timing is set properly

• B.

Transmit equipment timing is set properly

• C.

Receive equipment can find its place in the bit stream

• D.

Transmit equipment can find its place in the bit stream

C. Receive equipment can find its place in the bit stream
Explanation
Synchronization ensures that the receive equipment can find its place in the bit stream. This means that the receive equipment is able to accurately identify and locate the incoming bits within the stream, allowing for proper decoding and processing of the data. Without synchronization, the receive equipment may struggle to correctly interpret the incoming bits, leading to errors and loss of data.

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• 49.

### how many signal levels does an return-to-zero alternate mark inversion (RZ AMI) signal have?

• A.

1

• B.

2

• C.

3

• D.

4

C. 3
Explanation
An RZ AMI signal has three signal levels. In this type of signal, the voltage alternates between positive and negative values, with a zero voltage level representing a binary 0. The positive and negative voltage levels represent binary 1s, resulting in three signal levels in total.

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• 50.

### 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?

• A.

Non-return-to-zero (NZR) level

• B.

Non-return-to-zero mark

• C.

Non-return-to-zero space

• D.

Return-to-zero level

B. Non-return-to-zero mark
Explanation
The correct answer is "non-return-to-zero mark". In a non-return-to-zero (NRZ) encoding scheme, the information is represented by the presence or absence of a signal level. In this case, the transition from one state to the other only occurs when a mark bit is sent, indicating the presence of a signal. Therefore, the information is contained in the transition and specifically in the "mark" state.

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• Current Version
• Jul 30, 2023
Quiz Edited by
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• Jan 15, 2010
Quiz Created by
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