# Langley CST - 3D151 Vol 2

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Quizzes Created: 6 | Total Attempts: 2,099
Questions: 100 | Attempts: 418

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• 1.

### The process of condensation occurs when air particles are:

• A.

Pressurized, causing them to move closer together

• B.

Heated rapidly causing them to spread farther apart

• C.

Heated rapidly causing them to move closer together

• D.

Pressurized, causing them to be released to the atmosphere

A. Pressurized, causing them to move closer together
Explanation
Condensation occurs when air particles are pressurized, causing them to move closer together. When air is pressurized, the particles are forced closer, reducing the space between them. As a result, the particles lose energy and slow down, leading to the formation of liquid droplets or solid particles. This process is commonly observed when warm air cools down, such as when warm moist air comes into contact with a cold surface, leading to the formation of dew or fog.

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• 2.

### In hertz (Hz), what range of sound can the human ear detect?

• A.

200 to 3,000

• B.

20 to 20,000

• C.

20 to 200,000

• D.

Up to 2,600

B. 20 to 20,000
Explanation
The human ear can detect sound within the frequency range of 20 to 20,000 Hz. This range is commonly referred to as the audible range for humans. Frequencies below 20 Hz are known as infrasound and frequencies above 20,000 Hz are known as ultrasound, which are typically not audible to the human ear. Therefore, the correct answer is 20 to 20,000 Hz.

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• 3.

### The loudness of a sound is closely related to what part of the sine wave?

• A.

Amplitude

• B.

Frequency

• C.

Tone

• D.

Pitch

A. Amplitude
Explanation
The loudness of a sound is closely related to the amplitude of the sine wave. Amplitude refers to the maximum displacement of the particles in a medium as a sound wave passes through it. A higher amplitude corresponds to a louder sound, as it represents a greater amount of energy being transferred by the wave. Therefore, the correct answer is amplitude.

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• 4.

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

• A.

Power variations

• B.

Amplitude variations

• C.

• D.

Molecular breakdown

Explanation
Noise can be introduced into speech signals by various factors, including thermal agitation and black body radiation. Thermal agitation refers to the random movement of particles due to their thermal energy, which can cause fluctuations in the signal. Black body radiation refers to the emission of electromagnetic radiation by a perfect black body, which can also contribute to the introduction of noise in speech signals. Therefore, black body radiation is a valid explanation for the introduction of noise in speech signals.

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• 5.

### In hertz (Hz), what is the actual voice frequency band?

• A.

300 to 1,600

• B.

300 to 2,600

• C.

300 to 3,400

• D.

300 to 3,800

C. 300 to 3,400
Explanation
The actual voice frequency band, measured in hertz (Hz), ranges from 300 to 3,400. This means that the human voice typically produces sound waves within this frequency range.

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• 6.

### Which models of end offices in the Digital Multiplex System (DMS) family are commonly used at Air Force bases to provide base telephone services?

• A.

DMS-100 and Meridian System Logic (MSL)-100

• B.

DMS-100/200 and MSL-100

• C.

DMS-100/200 and DMS-200

• D.

DMS-200 and MSL-100

A. DMS-100 and Meridian System Logic (MSL)-100
Explanation
The correct answer is DMS-100 and Meridian System Logic (MSL)-100. These models of end offices in the Digital Multiplex System (DMS) family are commonly used at Air Force bases to provide base telephone services.

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• 7.

### Which model of Digital Multiplex System (DMS)-100 family switches is installed in compact modular cabinets?

• A.

• B.

DMS-100

• C.

DMS-200

• D.

Meridian System Logic (MSL)-100

D. Meridian System Logic (MSL)-100
Explanation
The Meridian System Logic (MSL)-100 model of Digital Multiplex System (DMS)-100 family switches is installed in compact modular cabinets.

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• 8.

### What is the maximum number of ports that a Meridian System Logic (MSL)-100 will support?

• A.

10,000

• B.

30,000

• C.

100,000

• D.

300,000

B. 30,000
Explanation
The maximum number of ports that a Meridian System Logic (MSL)-100 will support is 30,000. This means that the MSL-100 can handle a large number of connections or devices simultaneously. It is important for the system to support a high number of ports in order to accommodate a large volume of incoming and outgoing data traffic. This capability is crucial for organizations or businesses that require a robust and scalable communication system.

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• 9.

### Which type link is normally used to interconnect two peripheral modules (PM) in the Digital Multiplex System (DMS)?

• A.

Digital signal (DS)-1

• B.

DS-30A

• C.

DS-32

• D.

T1A

B. DS-30A
Explanation
DS-30A is the correct answer because it is the type of link that is typically used to interconnect two peripheral modules (PM) in the Digital Multiplex System (DMS). The DS-30A link provides a transmission rate of 30 Mbps, which is suitable for connecting peripheral modules and transferring data between them efficiently.

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• 10.

### What major area is connected to the central side (C-side) of a network module (NM) in the Digital Multiplex System (DMS)?

• A.

Control node (CN)

• B.

Peripheral module (PM)

• C.

Message controller (MC)

• D.

Central control

D. Central control
Explanation
The central side (C-side) of a network module (NM) in the Digital Multiplex System (DMS) is connected to the central control. This means that the central control is the major area connected to the C-side of the NM. The central control is responsible for managing and controlling the overall operation of the DMS network. It coordinates the functions of various modules and ensures efficient communication within the system.

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• 11.

### What is the mounting bracket called on which transmission or swtiching equipment is mounted in a Digital Multiplex System (DMS)?

• A.

Bay

• B.

Card

• C.

Shelf

• D.

Frame

A. Bay
Explanation
In a Digital Multiplex System (DMS), the mounting bracket on which transmission or switching equipment is mounted is called a "Bay." This term is commonly used in telecommunications to refer to a specific area or enclosure where the equipment is housed. Bays are designed to provide a secure and organized space for the installation and maintenance of various components, such as cards, shelves, and frames.

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• 12.

### What contains bays of the same functional equipment?

• A.

Bay

• B.

Card

• C.

Shelf

• D.

Frame

D. Frame
Explanation
A frame contains bays of the same functional equipment. Bays are compartments or sections within a frame that hold specific equipment. Frames are typically used in industries such as telecommunications or data centers to organize and house equipment efficiently. Each bay within a frame can hold similar equipment, making it easier to manage and access.

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• 13.

### Which Digital Multiplex System (DMS) component uses 16-bit Motorola 68000 or 8-bit Intel microprocessors?

• A.

A device controller

• B.

The network message controller

• C.

A peripheral module's (PM) peripheral processor (PP)

• D.

The computing module's (CM) central processing unit (CPU)

C. A peripheral module's (PM) peripheral processor (PP)
Explanation
The peripheral module's (PM) peripheral processor (PP) uses either a 16-bit Motorola 68000 or an 8-bit Intel microprocessor in the Digital Multiplex System (DMS). This component is responsible for controlling and managing the peripheral devices connected to the DMS. It handles the communication between the peripheral devices and the computing module's central processing unit (CPU). The choice of microprocessor depends on the specific requirements and capabilities of the DMS.

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• 14.

### How many channels of data does each digital signal (DS) 30 speech link carry?

• A.

30

• B.

32

• C.

34

• D.

36

B. 32
Explanation
Each digital signal (DS) 30 speech link carries 32 channels of data.

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• 15.

### Up to how many duplicated digital signals (DS)-30 links are used to connect a line group controller (LGC) to the network module (NM)?

• A.

6

• B.

8

• C.

16

• D.

24

C. 16
Explanation
The line group controller (LGC) is connected to the network module (NM) using duplicated digital signals (DS)-30 links. The question is asking for the maximum number of DS-30 links that can be used for this connection. The correct answer is 16, which means that up to 16 DS-30 links can be used to connect the LGC to the NM.

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• 16.

### What type of digital signal (DS) links are used to connect the Digital Multiplex System (DMS)-Core and the DMS-Bus?

• A.

1

• B.

30

• C.

30A

• D.

512

D. 512
Explanation
The correct answer is 512. In a Digital Multiplex System (DMS), the DMS-Core and DMS-Bus are connected using 512 DS links. These DS links are used to transmit digital signals between the core and the bus, allowing for communication and data transfer within the system.

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• 17.

### How many inter-message switch links (IMSL) can be configured in a SuperNode?

• A.

2

• B.

4

• C.

8

• D.

16

A. 2
Explanation
A SuperNode can have a maximum of 2 inter-message switch links (IMSL) configured. This means that it can connect with two other nodes or devices for message switching purposes. Having more IMSLs would require a higher level of complexity and resources, which may not be necessary or feasible in the given context.

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• 18.

### Where are the system clocks located within the SuperNode?

• A.

Network module (NM)

• B.

Peripheral module (PM)

• C.

Digital Multiplex System (DMS)-Bus

• D.

DMS-Core

C. Digital Multiplex System (DMS)-Bus
Explanation
The system clocks within the SuperNode are located in the Digital Multiplex System (DMS)-Bus.

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• 19.

### What type of digital signal (DS) protocol is used as a message carrier between the Digital Multiplex System (DMS)-Bus and the network modules (NM) and input/output controller (IOC)?

• A.

1

• B.

3

• C.

30

• D.

512

C. 30
Explanation
The correct answer is 30. The question is asking about the type of digital signal protocol used as a message carrier between the Digital Multiplex System (DMS)-Bus and the network modules (NM) and input/output controller (IOC). The answer 30 suggests that the protocol used is likely DS-30, which is a digital signal protocol commonly used in telecommunications for transmitting voice and data signals.

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• 20.

### Where are the DMS-Core and DMS-Bus housed?

• A.

Line trunk controller (LTC)

• B.

Dual plane combined core (DPCC)

• C.

Multipoint controller (MC)

• D.

Multipoint control unit (MCU)

B. Dual plane combined core (DPCC)
Explanation
The DMS-Core and DMS-Bus are housed in the Dual plane combined core (DPCC).

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• 21.

### What is the first step in the pulse code modulation (PCM) process?

• A.

Discrete amplitudes are assigned to the sampling pulses

• B.

A binary code number is assigned to the sample

• C.

The quantizer limits the amplitude of the pulses

• D.

The analog signal is band-limited

D. The analog signal is band-limited
Explanation
In pulse code modulation (PCM), the first step is to band-limit the analog signal. This means that the signal is filtered to remove any frequencies that are outside the desired range. Band-limiting is necessary to prevent aliasing, which can distort the signal during the sampling process. By limiting the bandwidth of the analog signal, it ensures that only the desired frequencies are captured accurately during the sampling process.

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• 22.

### In the pulse code modulation (PCM) process, changing the quantized samples into a binary word is called:

• A.

Encoding

• B.

Sampling

• C.

Quantization

• D.

Band limiting

A. Encoding
Explanation
In the pulse code modulation (PCM) process, changing the quantized samples into a binary word is called encoding. This is because encoding involves converting the analog signal into a digital format by assigning specific binary codes to each quantized sample. The binary word represents the amplitude of the signal at a given point in time and is used for transmission or storage purposes. Sampling refers to the process of measuring the amplitude of the analog signal at regular intervals, quantization is the process of approximating the continuous analog signal into discrete levels, and band limiting refers to restricting the frequency range of the signal.

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• 23.

### What is a method of putting many users on a single cable pair?

• A.

Time code multiplexing

• B.

Pulse code modulation

• C.

Pulse amplitude modulation

• D.

Time division multiplexing

D. Time division multiplexing
Explanation
Time division multiplexing is a method of putting many users on a single cable pair. It works by dividing the available time slots on the cable into smaller intervals and assigning each user a specific time slot to transmit their data. This allows multiple users to share the same cable pair without interfering with each other's transmissions. Each user takes turns transmitting their data during their allocated time slot, ensuring efficient utilization of the cable's capacity.

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• 24.

### In the time division multiplexing (TDM) process, the rate of sampling must be equal to:

• A.

The lowest frequency sampled multiplied by the sampling rate per cycle

• B.

The highest frequency sampled multiplied by the sampling rate per cycle

• C.

Twice the lowest frequency sampled multiplied by the sampling rate per cycle

• D.

Twice the highest frequency sampled multiplied by the sampling rate per cycle

B. The highest frequency sampled multiplied by the sampling rate per cycle
Explanation
In time division multiplexing (TDM), multiple signals are combined into a single signal by allocating each signal a specific time slot. The rate of sampling in TDM must be equal to the highest frequency sampled multiplied by the sampling rate per cycle. This is because the highest frequency sampled determines the maximum rate at which the signals need to be sampled in order to accurately reconstruct the original signals. By sampling at a rate equal to or higher than the highest frequency, the TDM system can capture all the necessary information from each signal and avoid aliasing or loss of data.

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• 25.

### Each 125 microsecond time period in the digital signal (DS) 30 signaling format (used within the voice network system) is called a:

• A.

Span

• B.

Frame

• C.

Channel

• D.

Snapshot

B. Frame
Explanation
In the digital signal (DS) 30 signaling format, each 125 microsecond time period is referred to as a "frame". This term is commonly used within the voice network system to describe a specific duration of time in which data is transmitted. Frames are essential for organizing and synchronizing the transmission of information within the DS 30 signaling format.

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• 26.

### Integrated Services Digital Network (ISDN) can combine voice and data services over the same wires because it uses

• A.

Internet data lines

• B.

Digital subscriber lines

• C.

Direct connection lines

• D.

Standard telephone lines

D. Standard telephone lines
Explanation
ISDN can combine voice and data services over standard telephone lines because it is a set of communication standards that allows for the transmission of digital data over traditional copper telephone lines. It uses a technique called circuit switching, which establishes a dedicated physical connection between the sender and receiver, allowing for simultaneous transmission of voice and data signals. This enables ISDN to provide faster and more reliable communication compared to traditional analog telephone lines.

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• 27.

### What type of information is transmitted on an Integrated Services Digital Network (ISDN) B-channel?

• A.

Call control

• B.

Supervisory

• C.

Signaling

• D.

User (voice or data)

D. User (voice or data)
Explanation
On an Integrated Services Digital Network (ISDN) B-channel, user information is transmitted. This includes both voice and data from the user. The B-channel is responsible for carrying the actual content of the communication, whether it is a phone conversation or data transfer. This is in contrast to other types of information that may be transmitted on ISDN, such as call control, supervisory, or signaling information, which are not directly related to the user's content.

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• 28.

### What are the two major established Integrated Services Digital Network (ISDN) transmission rates?

• A.

Bearer rate interface and data rate interface

• B.

Basic rate interface and primary rate interface

• C.

Basic rate interface and secondary rate interface

• D.

Primary rate interface and secondary rate interface

B. Basic rate interface and primary rate interface
Explanation
The correct answer is Basic rate interface and primary rate interface. ISDN is a telecommunications network that provides digital transmission of voice, video, and data over traditional telephone lines. The Basic rate interface (BRI) is designed for residential and small business use, offering two B channels for data and one D channel for signaling. The Primary rate interface (PRI) is intended for larger businesses, providing 23 B channels and one D channel in North America, and 30 B channels and one D channel in Europe. These two transmission rates are the major established options for ISDN connections.

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• 29.

### What is the Integrated Services Digital Network (ISDN) R-interface?

• A.

Connection point between a non-ISDN compatible device and a terminal adapter (TA)

• B.

Connection point between a network termination 1 device and the ISDN

• C.

Incoming connection point of a network termination 2 device

• D.

Outgoing connection point of a network termination 2 device

A. Connection point between a non-ISDN compatible device and a terminal adapter (TA)
Explanation
The Integrated Services Digital Network (ISDN) R-interface is the connection point between a non-ISDN compatible device and a terminal adapter (TA). This interface allows the non-ISDN device to connect to the ISDN network through the TA, which acts as a bridge between the two systems. The TA converts the signals from the non-ISDN device into a format that can be transmitted over the ISDN network, enabling communication between the two devices.

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• 30.

### The Network Layer of the Open Systems Interconnection (OSI) model provides the:

• A.

Physical characteristics between the Integrated Services Digital Network (ISDN) interface and the network

• B.

Logical links between customer equipment and the circuit switch

• C.

Final preparation of the signal before it is routed

• D.

Actual routing of the signal

D. Actual routing of the signal
Explanation
The Network Layer of the OSI model is responsible for the actual routing of the signal. This layer takes care of determining the best path for the data packets to travel from the source to the destination across different networks. It handles tasks such as addressing, packet forwarding, and routing protocols. By analyzing the network topology and making decisions based on routing tables, the Network Layer ensures that data packets are efficiently delivered to their intended destinations.

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• 31.

### What circuit board in the REDCOM switch provides two signaling channels and is only necessary when interfacing with an Integrated Services Digital Network (ISDN)-capable switch?

• A.

T1 legacy to Internet

• B.

Message transceiver interface

• C.

T1 direct digital interface

• D.

Basic rate U

B. Message transceiver interface
Explanation
The correct answer is "Message transceiver interface". The message transceiver interface circuit board is necessary when interfacing with an Integrated Services Digital Network (ISDN)-capable switch. It provides two signaling channels for communication between the REDCOM switch and the ISDN switch. This allows for the transmission of messages and signaling information between the two switches.

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• 32.

### One of the main purposes of the Integrated Services Digital Network (ISDN) handset telephone test set is to:

• A.

Detect noise

• B.

Insert tones

• C.

Verify a dial tone

• D.

Insert signal delay

C. Verify a dial tone
Explanation
The main purpose of the Integrated Services Digital Network (ISDN) handset telephone test set is to verify a dial tone. This means that the test set is used to check if a dial tone is present and functioning properly on the telephone line. It ensures that the user can make outgoing calls successfully by confirming the availability of a dial tone.

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• 33.

### What is the frame rate in feet per second (FPS) for transmitting video teleconferencing data on the Integrated Services Digital Network (ISDN)?

• A.

24

• B.

30

• C.

32

• D.

64

B. 30
Explanation
The frame rate in feet per second (FPS) for transmitting video teleconferencing data on the Integrated Services Digital Network (ISDN) is 30. This means that 30 frames of video are transmitted every second over the ISDN network.

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• 34.

### What component in the video teleconferencing (VTC) system converts analog signals to digital signals?

• A.

Camera

• B.

Coder/decoder (CODEC)

• C.

Network termination 1

• D.

Central processing unit (CPU)

B. Coder/decoder (CODEC)
Explanation
The correct answer is the coder/decoder (CODEC). In a video teleconferencing (VTC) system, the CODEC is responsible for converting analog signals, such as those from a camera, into digital signals that can be transmitted over a network. The CODEC also decodes digital signals received from the network back into analog signals for display on a screen or monitor. It plays a crucial role in ensuring the compatibility and quality of audio and video signals in a VTC system.

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• 35.

### How many channels are used when a voice over Internet Protocol (VoIP) session is established between a private branch exhange (PBX) and another IP host?

• A.

One, they share the same channel

• B.

Two, one for each direction

• C.

Three, two to transmit/receive and one to signal

• D.

Four, two to transmit and two to receive

B. Two, one for each direction
Explanation
When a voice over Internet Protocol (VoIP) session is established between a private branch exchange (PBX) and another IP host, two channels are used, one for each direction. This means that there is a separate channel for transmitting audio from the PBX to the IP host, and another channel for transmitting audio from the IP host to the PBX. This allows for bidirectional communication between the two devices during the VoIP session.

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• 36.

### What component of voice over Internet Protocol (VoIP) is an endpoint on the network that provides real time, bi-directional communications between H.323 terminals and other switch circuit networks (SCN)?

• A.

Gateway

• B.

Gatekeeper

• C.

• D.

Multipoint control unit (MCU)

A. Gateway
Explanation
A gateway is a component of VoIP that acts as an endpoint on the network and facilitates real-time, bi-directional communication between H.323 terminals and other switch circuit networks (SCN). It serves as a bridge between different communication protocols and enables the conversion of voice signals into digital data packets that can be transmitted over the IP network. Gateways also handle tasks such as call routing, protocol conversion, and signal processing, allowing for seamless communication between different networks and devices.

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• 37.

### What component of voice over Internet Protocol (VoIP) provides call management functions in a defined local area called a zone?

• A.

Gateway

• B.

Gatekeeper

• C.

• D.

Multipoint control unit (MCU)

B. Gatekeeper
Explanation
A gatekeeper is a component of Voice over Internet Protocol (VoIP) that provides call management functions in a defined local area called a zone. It acts as a central control point for managing and directing calls within the network. It authenticates and authorizes users, controls bandwidth allocation, manages call routing, and provides other administrative functions. A gatekeeper ensures efficient and secure communication by regulating access and managing resources in the VoIP network.

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• 38.

### How many milliseconds should the one-way delay be from endpoint to endpoint in order to implement voice over Internet Protocol (VoIP)?

• A.

Less than 50

• B.

Less than 150

• C.

Greater than 50

• D.

Greater than 150

B. Less than 150
Explanation
In order to implement voice over Internet Protocol (VoIP), the one-way delay from endpoint to endpoint should be less than 150 milliseconds. This is because any delay greater than this can result in noticeable voice quality degradation and communication issues. Therefore, to ensure smooth and real-time communication, it is important to keep the one-way delay below 150 milliseconds.

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• 39.

### What is the control system that generates a signal with a fixed relation to the phase of a reference signal and responds to both the frequency and the phase of the input signals?

• A.

Quality of service (QoS)

• B.

Remote control protocol (RCP)

• C.

Forward error correction (FEC)

• D.

Phase-locked loop (PLL)

D. Phase-locked loop (PLL)
Explanation
A phase-locked loop (PLL) is a control system that generates a signal with a fixed relation to the phase of a reference signal. It not only responds to the frequency but also the phase of the input signals. In other words, a PLL locks onto the phase of a reference signal and adjusts the frequency and phase of its output signal accordingly. This makes it a suitable control system for applications that require precise synchronization and tracking of phase and frequency, such as in communication systems, audio/video equipment, and clock generation.

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• 40.

### What are frequencies from 30 to 300 megahertz (MHz) internationally designated as?

• A.

High

• B.

Medium

• C.

Very high

• D.

Ultra high

C. Very high
Explanation
Frequencies from 30 to 300 megahertz (MHz) are internationally designated as "Very high." This range of frequencies falls within the VHF (Very High Frequency) band, which is commonly used for various purposes such as FM radio broadcasting, television broadcasting, and aviation communication.

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• 41.

### The ultra high frequency designation applies to frequencies from:

• A.

3 to 30 megahertz (MHz)

• B.

300 to 3,000 MHz

• C.

3 to 30 gigahertz (GHz)

• D.

30 to 300 GHz

B. 300 to 3,000 MHz
Explanation
The correct answer is 300 to 3,000 MHz. Ultra high frequency (UHF) refers to a range of frequencies between 300 to 3,000 MHz. This range is commonly used for various applications like television broadcasting, wireless communication, and satellite communication. It is higher than the frequencies used for AM and FM radio but lower than the frequencies used for microwave and radar systems.

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• 42.

### Which of the following frequencies has the shortest wavelength?

• A.

14 kilohertz (kHz)

• B.

1.4 megahertz (MHz)

• C.

14 MHz

• D.

140 MHz

D. 140 MHz
Explanation
The correct answer is 140 MHz because the frequency and wavelength of a wave are inversely proportional. This means that as the frequency increases, the wavelength decreases. Since 140 MHz has the highest frequency among the given options, it will have the shortest wavelength.

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• 43.

### A mode of operation in which communication is possible between two or more stations, in both directions, using the same frequency, is called:

• A.

Simplex

• B.

Duplex

• C.

Hybrid

• D.

Half-duplex

A. Simplex
Explanation
Simplex is the correct answer because it refers to a mode of operation where communication can occur between two or more stations using the same frequency, but only in one direction at a time. In simplex mode, there is no simultaneous transmission or reception, and stations take turns sending and receiving messages. This mode is commonly used in applications where one station needs to transmit data to multiple stations, such as radio broadcasting or walkie-talkies.

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• 44.

### What communication mode(s) of operation allows two or more stations to send intelligence in both directions but not simultaneously?

• A.

Duplex only

• B.

Half duplex only

• C.

Duplex and half duplex

• D.

Simplex and half duplex

D. Simplex and half duplex
Explanation
Simplex mode of operation allows communication in only one direction, where one station can transmit while the other can only receive. Half duplex mode allows communication in both directions, but not simultaneously, meaning that stations can take turns transmitting and receiving. Therefore, the correct answer is "Simplex and half duplex" as both modes allow two or more stations to send intelligence in both directions, but not simultaneously.

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• 45.

### Producing radio frequency (RF) energy and radiating useful signals into space is the purpose of:

• A.

Reciever

• B.

Transmitter

• C.

Antenna coupler

• D.

Transmission lines

B. Transmitter
Explanation
A transmitter is responsible for producing radio frequency (RF) energy and transmitting useful signals into space. It converts the electrical signals into electromagnetic waves that can be transmitted through the air or space. The transmitter is an essential component in any communication system as it enables the transmission of information over long distances.

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• 46.

### What type modulation produces a constant amplitude transmission?

• A.

Frequency

• B.

Amplitude

• C.

Phased

• D.

Pulse

A. Frequency
Explanation
Frequency modulation produces a constant amplitude transmission. In this type of modulation, the frequency of the carrier signal is varied in proportion to the instantaneous amplitude of the modulating signal. The amplitude of the carrier signal remains constant throughout the modulation process. This allows for efficient transmission of signals with minimal distortion, as variations in the amplitude of the signal are minimized.

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• 47.

### The ability to maintain a constant output carrier frequency refers to a transmitter's frequency:

• A.

Accuracy

• B.

Distortion

• C.

Sensitivity

• D.

Signal-to-noise ratio

A. Accuracy
Explanation
The ability to maintain a constant output carrier frequency refers to the accuracy of a transmitter's frequency. This means that the transmitter is able to consistently produce the desired carrier frequency without any significant deviations or variations. Accuracy is an important factor in ensuring reliable communication and minimizing interference with other signals. It allows the transmitter to stay within the specified frequency range, ensuring that the transmitted signal can be properly received and decoded by the intended receiver.

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• 48.

### The process of mixing or combining two frequencies in a nonlinear device in an amplitude modulated (AM) receiver is called:

• A.

Limiting

• B.

Amplifying

• C.

Heterodyning

• D.

Discriminating

C. Heterodyning
Explanation
Heterodyning is the process of mixing or combining two frequencies in a nonlinear device in an amplitude modulated (AM) receiver. This technique is used to convert the received signal to a lower frequency, known as the intermediate frequency (IF), which is easier to process and amplify. By mixing the received signal with a local oscillator signal, a new frequency is generated in the IF range, allowing for easier filtering and amplification of the desired signal. Heterodyning is a crucial step in the demodulation process of an AM receiver.

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• 49.

### What component of a frequency modulated (FM) receiver removes the original signal from the sidebands and recreates the audio intelligence?

• A.

Limiter

• B.

Detector

• C.

Amplifier

• D.

Discriminator

D. Discriminator
Explanation
The discriminator is the component of a frequency modulated (FM) receiver that removes the original signal from the sidebands and recreates the audio intelligence. It does this by demodulating the FM signal and converting it back into an audio signal. The discriminator is responsible for extracting the audio information from the FM carrier wave and restoring it to its original form.

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• 50.

### What characteristic enables a receiver to reproduce a desired signal from several closely spaced stations or from interfering frequencies?

• A.

Sensitivity

• B.

Selectivity

• C.

• D.

Thermal noise

B. Selectivity
Explanation
Selectivity is the characteristic that enables a receiver to reproduce a desired signal from several closely spaced stations or from interfering frequencies. It refers to the ability of a receiver to separate and extract the desired signal while rejecting unwanted signals or interference. A selective receiver is able to filter out unwanted frequencies and only amplify and process the specific frequency or range of frequencies that it is tuned to receive. This allows for clear and accurate reproduction of the desired signal, even in the presence of nearby stations or interfering frequencies.

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• Current Version
• Mar 21, 2023
Quiz Edited by
ProProfs Editorial Team
• Jun 02, 2017
Quiz Created by
Jordan

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