Ch 1 - P 1 - Terminology

Question 1

Amplitude

Answer 1

The maximum absolute value reached by a voltage or current waveform.

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Question 2

Amplitude Modulation (AM)

Answer 2

The modulation in which the amplitude of a carrier wave is varied in accordance with some characteristic of the modulating signal.

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Question 3

Analog Signal

Answer 3

A signal in the form of a wave that uses continuous variations of a physical characteristic over time (e.g., voltage amplitude, frequency) to transmit information.

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Question 4

Attenuation

Answer 4

The ratio in decibels of the output power (or voltage) to the input power (or voltage) when the load and source impedance are matched to the characteristic impedance of the cable.

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Question 5

ATM

Answer 5

Asynchronous Transfer Mode - A high-speed packet switching protocol that uses fixed-length (53-byte) packets organized into cells to carry all types of traffic (e.g., voice, data, still image, audio/video). Fixed length cells allow cell processing to occur in the hardware, thereby reducing transit delays. ATM is designed to take advantage of high-speed transmission media, such as E3, synchronous optical network (SONET), and T3. TDMM Page G-13

Question 6

AWG

Answer 6

American Wire Gauge - A system used to specify wire size. The greater the wire diameter the smaller the AWG value.

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Question 7

Bandwidth

Answer 7

A range of frequencies available for signaling expressed in hertz (Hz). It is used to denote the potential information handling capacity of the medium, device, or system.

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Question 8

Broadband Cable

Answer 8

Composite baseband video and audio signals that are amplitude and frequency modulated, respectively, with an RF carrier in accordance with the video and audio information that need to be conveyed (e.g., CATV).

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Question 9

CO

Answer 9

Central Office - A common carrier switching center office (also called public exchange) that is conveniently located in areas to service subscriber homes and businesses. It provides telephony service (lines) that are connected on a local loop. The CO contains switching equipment that can switch calls locally or to long-distance carrier telephone offices.

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Question 10

Codec

Answer 10

A device that converts speech to a digital signal and its subsequent decoding to speech.

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Question 11

Cross Talk

Answer 11

The signal interference between cable pairs, which may be caused by a pair picking up unwanted signals from either adjacent pairs of conductors or nearby cables.

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Question 12

Decibel

Answer 12

A logarithmic unit for measuring the relative voltage, current, or power of a signal. One tenth of a bel.

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Question 13

Delay Skew

Answer 13

The difference in propagation delay between any pairs within the same cable sheath.

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Question 14

Digital Signal

Answer 14

Information used by digital devices in the form of a sequence of discrete pulses (e.g., a binary signal with two values used to transmit the two states [0, 1]).

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Question 15

Dispersion

Answer 15

1. The loss of signal resulting from the scattering of light pulses as the are transmitted through a medium.
2. The widening or spreading out of a the modes in a light pulse as it progresses along an optical fiber.
3. The characteristics of the sound coverage field of a speaker.

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Question 16

EMI

Answer 16

Electromagnetic Interference
Stray electrical energy radiated from electronic equipment and electronics systems (including cabling).

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Question 17

Frequency

Answer 17

The number of cycles that a periodic signal completes in a given time. If the unit of time is a one second, the frequency is stated in hertz (Hz). One Hz is equal to one cycle per second.

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Question 18

IP

Answer 18

Internet Protocol - The Open Systems Interconnection (OSI) Reference Model Layer 3 (network layer) protocol most commonly used for internet working. Required for communications over the internet.

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Question 19

ISDN

Answer 19

Integrated Services Digital Network - A digital communications facility designed to provide transparent end-to-end transmission of voice, data, audio/video and still images across the public switched telephone (PSTN). Different versions and configurations exist regionally and internationally.

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Question 20

NVP

Answer 20

Nominal Velocity of Propagation - The coefficient used to determine the speed of transmission along a cable relative to the speed of light in a vacuum, typically expressed as a percentage. Also called phase velocity and velocity of propagation.

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Question 21

PCM

Answer 21

Pulse Code Modulation - A technique for representing an analog signal as a string of bits. The analog signal is converted to a bit string by periodically sampling the amplitude of the analog signal and representing each sample as a binary number.

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Question 22

Phase

Answer 22

1. The relationship in time between two waveforms of the same frequency.
2. The relationship in time between two parameters of a single waveform (e.g., voltage and current).

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Question 23

PoE

Answer 23

Power over Ethernet - A network subsystem that offers the ability for the LAN switching infrastructure to provide power over balanced twisted-pair cabling to an endpoint device (e.g., access point [AP], camera, telephone set).

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Question 24

Propagation Delay

Answer 24

The time required for a signal to travel from one end of the transmission path to the other end. (TIA)

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Question 25

QAM

Answer 25

Quadrature Amplitude Modulation - A means of encoding digital information over radio, wireline, or optical fiber transmission links. It is a modulation technique that uses variations in signal amplitude and phase, allowing data encoded symbols to be represented as a multitude of 2N states, where each state encodes 2N bits (e.g. 2, 4, 8, 16, 32, 64, 128, 256).

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Question 26

Sinusoid

Answer 26

An oscillating, periodic signal that is completely described by three parameters; amplitude, frequency, and phase.

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Question 27

TDM

Answer 27

Time Division Multiplexing - A process that combines binary data from several different sources (e.g., voice channels) into a single composite bit stream.

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