Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ece - est > Principles of Communications > Flashcards

Principles of Communications Flashcards

You may prefer our related Brainscape-certified flashcards:
Early Childhood Education flashcards
1
Q

it is the process of sending, processing and receiving information by electrical or electronic means

A

Communications System

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

it refers to the basic process of exchanging information by - electronic means

A

Communications System

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

1799 , Invented the electric Battery

A

Alessandro Volta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

1830 , He transmitted the first practical electrical signal over one mile of wire to activate electromagnet

A

Joseph Henry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

1837, He Invented the telegraph

A

Samuel Finley Breese Morse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

1843, He Invented the Facsimile

A

Alexander Bain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

1875, She designed a fixed-length binary code for telegraph

A

Emily Baudot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

1876 , He patented the telephone

A

Alexander Graham Bell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

1877 , He invented phonograph

A

Thomas Alva Edison

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

1864 , He predicted mathematically radio propagation.

A

James Clerk Maxwell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

1880 , He patented the photophone

A

Alexander Graham Bell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

1887, He verified experimentally Maxwell’s Theory

A

Heinrich Hertz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

1888, He invented Liquid Crystal

A

Friedrich Reinitzer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

1895, He demonstrated Wireless Transmission

A

Guglielmo Marconi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

1906, He invents Amplitude Modulation (AM)

A

Reginald Fessenden

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

1920, Radio Station _____ Broadcasts the first regular licensed AM radio transmission

A

KDKA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

1927, he produced the first all-electronic television transmission

A

Philo Farnsworth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

1930, He was the first to transmit images through a single glass fiber

A

Heinrich Lamm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

1933, He invented invented FM (Frequency Modulation) radio

A

Major Edwin Armstrong

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

1937 , He Invented binary coded pulse-code modulation

A

Alec Reeves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

1946, They inaugurated the first mobile telephone system for the public known as mobile telephone system

A

AT & T ( American Telephone and Telegrap Company )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

1947, they developed the concept of cellular telephony but the technology to realized the concept did not yet exist

A

AT & T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

1954 , They announced imaging bundles, which propelled the fiber optics revolution and led to the development of flexible fiberscope

A

Abraham Van Heel, Harold Hopkins, Narinder Kapany

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

1957, Russia Launched the world’s first artificial satellite named

A

Sputnik I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

1962, NASA launches its first artificial satellite named

A

Telstar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

1970, HDTV(high-definition Tv) was introduced in

A

Japan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

1972 , they invented the TCP ( Transmission Control Protocol )

A

Bob Kahn and Vint Cerf

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

1973, he invents Ethernet to wire local computers together

A

Robert Metacalfe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

1973, He invented the first practical mobile phone

A

Martin Cooper of Motorola

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

1983, they opened the first commercial cellular telephone system in the United States

A

AT & T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

1991, He invents the WWW (World Wide Web)

A

Tim Burners-Lee

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

1996, First Smartphones

A

BlackBerry, Nokia and Palm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

It is the source of information, which must be delivered or transmitted to a particular destination over a channel.

It is a collection of one or more electronic devices or circuits that converts the original source information to a form more suitable for transmission

performs encoding and modulation

A

Transmitter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Three Basic Transmitter Components

A

Modulator (modulates the signal)
Amplifier (provides power to the signal)
Oscillator(provides the carrier signal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

it is the destination upon which information from the transmitter is delivered
it is a collection of electronic devices and circuits that accepts the transmitted signals from the transmission medium and then converts those signals back to their original form

performs decoding and demodulation

A

Receiver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Three Basic Receiver Components

A

Demodulator or Detector (demodulates the signal)
Amplifiers (it provides power to the signal)
Output Devices (such as speakers,monitor,printer etc).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

it is the path or medium that the information travels from the transmitter to the receiver(i.e it provides a means of transporting signals between a transmitter and a receiver).
Attenuation ( sometimes referred to as power loss) occurs at this point.)

A

Transmission Medium or Transmission Channel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Two Classifications of Transmission Media

A

Guided Media ( Wired ) - in a form of conduit
-Trasmission lines (Twisted Pairs , Twin Lead , Open-Wire Lines, Coaxial Cables, etc.)

Unguided Media (Wireless) - radiated through air or vacuum
-Free Space
-Earth’s Atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

it is an electronic circuit which is capable of increasing the signal magnitude or amplitude without appreciably altering the signal waveform characteristics.

A

Amplifier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

active amplifier with a maximum efficiency of 25 or 50% and a conduction angle of 360 degrees and the distortion is Low

A

Class A Amplifier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

cut-off amplifier with a maximum efficiency of 75% and a conduction angle of 180 degrees and the distortion is High

A

Class B Amplifier

42
Q

a little above cut-off region with a maximum efficiency between class A and class B and a conduction angle between 180 to 359 degrees and the distortion is moderate

A

Class AB

43
Q

Below Cut-off region amplifier with a maximum efficiency of more that 90% and a conduction angle of less than 180 and the distortion is Very High

A

Class C

44
Q

It is a circuit that produces a periodic waveform on its output with only DC supply voltage as an input.
It is a non-rotating device for producing alternating current, the output frequency of which is determined by the characteristics of the device
It can be thought as an amplifier that provides itself ( through feedback ) with an input signal

A

Oscillator

45
Q

Types of Oscillator

A

LC
RC
Crystal

46
Q

type of oscillator commonly used at High Frequencies uses a parallel resonant circuit or tank circuit

A

LC Oscillator (Inductor,Resistor)
-Hartley Oscillator (uses tapped Coil)
-Colpitts Oscillator (uses split Capacitor)
-Clapp Oscillator (similar to colpitts with additional capacitor in series with the inductor)
-Armstrong Oscillator (uses tickler coil)

47
Q

type of oscillator commonly used at Low Frequencies. provide regenerative feedback and to determine the frequency of operations

A

RC Oscillator (Resistor,Capacitor)
-Wien Bridge Oscillator (Utilize Lead-lag Circuit)
-Phase Shift Oscillator uses a series of RC Sections

48
Q

type of oscillator usually used to produce an output which is highly stable and at a very precise frequency

A

Crystal Oscillator

49
Q

It is a frequency-selective circuit which are designed to pass some frequencies and reject others

A

Filters

50
Q

filters that constructed using resistor and capacitor or inductors and capacitors that do not amplify are called

A

Passive Filters

51
Q

filters that uses RC networks with feedback in op-amp circuits, switched capacitor filters, crystal and ceramic filters , surface acoustic wave(SAW) filters and digital filters implemented with digital signal processing(DSP) techniques are called

A

Active Filters

52
Q

Basic Types of Filter Circuits

A

Low-pass Filter (pass frequency below cutoff)
High-pass Filter(pass frequency above cutoff)
Bandpass Filter(pass frequency over a narrow range)
Band-reject Filter(reject frequencies over narrow range)
All-pass filter (passes all frequencies equally)

53
Q

it is simply the number of times a particular phenomenon occurs in a given period of time.

A

Frequency

54
Q

it may be number of voltage polarity alternations or electromagnetic field oscillations that takes place in a span of time; each alternation or oscillation is known as a

A

Cycle

55
Q

frequency is measured in

A

cycle per second , or Hertz(hz) named after Heinrich Hertz, who was a pioneer in the field of electromagnetics.

56
Q

Frequency Formula:

A

f = 1/Time (in second)

57
Q

it is the time required for one complete cycle of a repetitive waveform, and it is known as the reciprocal of frequency

A

Period

58
Q

Time Formula:

A

f = 1/Frequency (in Hertz)

59
Q

waves travel at characteristic speeds depending on the type of wave and the nature of the propagation of the medium
electromagnetic wave velocity in the atmosphere or free space is approximately equal to the speed of light in vacuum

A

Velocity of Propagation
vp = vf * c
where:
vf = velocity factor , unitless
c = speed of light in a vacuum
c = 3x10^8 m/s
c = 186000 mi/s

60
Q

it is the distance between two similar points of similar cycles of a periodic wave

the distance traveled by an electromagnetic wave during the time of one cycle

A

Wavelength (lambda)
lambda = c / f or = vp / f
where:
c = 3x10^8 m/s
f = frequency in hertz
vp = velocity of propagation m/s

61
Q

it is defined as a single-valued function of time that conveys information(i,e for every instant of time there is a unique value of the function)

A

Signal

62
Q

Two types of Signal

A

Analog Signal (Continous) Ex : sine wave
Digital Signal (Discrete) Ex: binary code

63
Q

is the process of extracting information from a signal, conditioning a signal from subsequent use, signal transformation, or altering a signal structure.

A

Signal Processing

64
Q

Simply describes the frequency content of the signal

A

Spectra

65
Q

Two Types of Waveform Representation:

A

TDR - Time Domain Representation
FDR - Frequency Domain Representation

66
Q

the signal amplitude is plotted against time like in a standard oscilloscope display

A

Time Domain Representation

67
Q

the signal amplitude is plotted against frequency like in a spectrum analyzer

A

Frequency Domain Representation

68
Q

It is also known as -3db bandwidth or half-power bandwidth which indicates the portion of the electromagnetic spectrum occupied by a signal.

A

Bandwidth - (Frequency Range)

69
Q

Bandwidth Formula:

A

B = f(upper) - f(lower) or B(eff) = (pi/2)(B)
f(upper) = fr + B/2
f(lower) = fr - B/2
fr = (f(upper) + f(lower) / 2
where:
B= bandwidth, hz , B(eff) = effective bandwidth
fr = Resonant Frequency , hz

70
Q

these are also known as cut-off points , breakup points and -3db points

A

Half - Power Points

71
Q

Half Power points(-3db) :
Voltage, Current and Power :

A

V = 0.707Vmax
I = 0.707Imax
P = 0.5Vmax

72
Q

Electromagnetic Spectrum Mnemonics:

A

Every, Very, Very, Loving, Mom, Has, Very, Understanding, Son, Except, I

Inject, Viagra, Until, Xplosive, Growth, of Cock

VHS at 3:30 kasi Ma Galing - (frequency ranges)

My kili-kili Has D Most Decent C Mill

73
Q

Electronics Communications Systems uses frequecy ranges from

A

Very Low Frequency up to Light Frequencies

74
Q

Radio waves are signals with frequencies that lies between _ to _ and commonly used in wireless communication systems

A

Very Low Frequency up to Extremely High Frequencies ,

75
Q

it is the fundamental quantity representing the rate at which energy is used, and it is more readily measurable since it can be converted to heat

A

Power

76
Q

it literally means one-tenth of a Bel, it is a logarithmic unit that can be used to measure ratio (not an absolute unit, but rather , it indicates the relation between two powers.)

A

Decibel

77
Q

Decibel Computations :

A

Bel = log(P2/P1)
P(db) = 10log ( P2/P1 )
P(db) = 20log( V2/V1 )
P(db) = 20log( I2/I1 )
P(dbm) = 10log (P / 1mW)
P(dbu) = 10log (P / 1uW)
P(dbW) = 10log (P / 1W)

78
Q

the Unit Neper defined in terms of natural logarithm is equivalent to

A

20 log (e) or 8.686 decibels

79
Q

Gains are expressed in ______ decibels while Losses are expressed in _______ decibels

A

Gains (positive decibels)
Losses (negative decibels)

80
Q

It is a random, unwanted , undesireable electrical energy that enters the communication system via the communicating medium and interferes with the transmitted message

A

Noise

81
Q

is any waveform pertubation or deviation caused by the imperfect response of the system to the desired signal

A

Distortion

82
Q

is any contamination by extraneous or external signals from human sources, other transmitters, power lines, machinery, switching circuits, etc.

A

Interference

83
Q

it is a noise that is present regardless whether there is a signal present or not

A

Uncorrelated Noise

84
Q

it is a noise that cannot be present in a circuit unless there is a signal

A

Correlated Noise

85
Q

it is a type of noise that affects the communication system coming from the outside environment

A

External Noise

86
Q

it is also known as Static Noise which is naturally occuring electrical disturbance that originates within Earth’s atmosphere. It is caused by lightning discharges in thunderstorms and other natural electrical disturbances . it has very high peak-to-average power ratio and dominates at lower frequencies

A

Atmospheric Noise

87
Q

it consist of electrical signals that originate from outside Earth’s Atmosphere and is also known as Space or Deep-space Noise

A

Extraterrestrial Noise

88
Q

it is generated directly from the sun’s heat like in solar cycle every 11 years like corona and sunspots , it is more important at higher frequencies

A

Solar Noise

89
Q

it is also known as Sky noise, Stellar noise or Black Body noise. it is an RF noise radiated by distant stars, and what they lack in nearness, they nearly makeup in numbers. it is also continously distributed throught the galaxies

A

Cosmic Noise

90
Q

it is noise other than solar and cosmic noise

A

Galactic Noise

91
Q

it is also known as man-made noise, since it is produced by mankind. usually between 1-600MHz usually most intense in industrial and densely populated areas

A

Industrial Noise

92
Q

it is an electrical interference generated within a device or circuit

A

Internal Noise

93
Q

it is associated with the rapid and random movement of electrons within a conductor due to thermal agitation. It is known as Brownian noise after its discoverer and also as Johnson Noise after the man related to Brownian particle movement of electron movement. it is also known as White Noise because of a random movement and also kwown as Gaussian Noise

A

Thermal Noise

94
Q

Noise Power Formula:

A

Pn = kTB
k = Boltzmann’s constant (shift 7 > 25)
B = Bandwidth, hz
T = Temperature in Kelvin

Kathryn Bernardo

Total Noise Power = Pn1 + Pn2 + …

95
Q

Noise Voltage Formula :

A

Vn = Sqrt(4kTBR)
R=Resistance

nag squirt ng apat na beses si Kathryn Bernardo

Total Noise Voltage and Current
= Sqrt (Vn1^2 + Vn2^2 + Vn3^2 + …. )
or
= Sqrt (In1^2 + In2^2 + In3^2 +… )

96
Q

it is caused by the random arrival of carriers (holes and electrons) at the output element of an electronic device. it is due to random variations in current flow specifically in active devices such as tubes, transistors , semiconductor diodes, etc it is commonly found in devices with PN junctions

A

Shot Noise

97
Q

Noise Current Formula In:

A

In = Sqrt ( 2qBI(dc) )
where :
q = 1.6x10^-19 C, electron charge in Coulomb (shift 7 > 23)
or
In = Sqrt( 2B (I(dc) + 2(I(s)) q )
where :
I(s) = reverse saturation current

98
Q

it is also known as transistor noise since it is commonly found in transistors. it is similar to shot noise but occurs only in devices where singler current separates into two or more paths

A

Partition Noise

99
Q

it is also known as Modulation noise ,Flicker noise or 1/f noise because its noise power varies inversely with frequency. it is also known as pink noise because there is more energy in low frequency end of the spectrum. used for testing and setting up audio systems

A

Excess Noise

100
Q

it is an irregular, random variation produced by any modification to a stream of carriers as they pass from input to output of a device. its greates effect is in microwave region, and therefore also known as high frequency noise

A

Transit Time Noise

101
Q

it is also known as popcorn noise which is a low frequency noise found in transistors such as BJTs . it appears as series of burst at two or more levels

A

Burst Noise

102
Q

these are large noise spikes present in the avalanche current due to oscillation that result in the avalanching region

A

Avalanche Noise

ece - est (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions