Chapter 1: Communication's Principles

Question 1

S P R of info by electrical or electronic means

Answer 1

Communications System

Question 2

Alessandro Volta - electric battery

Answer 2

1799

Question 3

Joseph Henry - transmitted first practical signal over one mile of wire to activate electromagnet

Answer 3

1830

Question 4

Samuel Morse - invented telegraph

Answer 4

1837

Question 5

Alexander Bain - Facsimile

Answer 5

1843

Question 6

Transatlantic cable laid and failed

Answer 6

1858

Question 7

Emile Baudot - binary code for telegraph

Answer 7

1875

Question 8

Alexander Graham Bell patented the telephone.

Answer 8

1876

Question 9

Thomas Alva Edison invented the phonograph.

Answer 9

1877

Question 10

James Clerk Maxwell predicted mathematically radio propagation.

Answer 10

1864

Question 11

Alexander Graham Bell patented the photophone.

Answer 11

1880

Question 12

Heinrich Hertz verified experimentally Maxwell’s theory.

Answer 12

1887

Question 13

Friedrich Reinitzer invented liquid crystal.

Answer 13

1888

Question 14

Guglielmo Marco demonstrated wireless transmission.

Answer 14

1895

Question 15

Reginald Fessenden invents AM

Answer 15

1906

Question 16

Radio Station KDKA broadcasts the first regular licensed AM radio transmission.

Answer 16

1920

Question 17

Philo Farnsworth produced the first all-electronic television transmission.

Answer 17

1927

Question 18

Heinrich Lamm was the first to transmit images through a single glass fiber.

Answer 18

1930

Question 19

Major Edwin Armstrong invented FM (frequency modulation) radio.

Answer 19

1933

Question 20

Alec Reeves invented binary coded pulse-code modulation.

Answer 20

1937

Question 21

First use of two-way radio (walkie-talkies).

Answer 21

1939

Question 22

Invention and perfection of radar (World War II).

Answer 22

1940

Question 23

The AT&T (American Telephone and Telegraph Company) inaugurated the first mobile telephone system for the public known as Mobile Telephone System.

Answer 23

1946

Question 24

AT&T developed the concept of cellular telephony but the technology to realize the concept did not yet exist.

Answer 24

1947

Question 25

Abraham van Heel, Harold Hopkins and Narinder Kapany announced imaging bundles, which propelled the fiber optics revolution and led to the development of flexible fiberscope.

Answer 25

1954

Question 26

Russia launched the world's first artificial satellite, Sputnik 1.

Answer 26

1957

Question 27

Citizens band radio first used.

Answer 27

1961

Question 28

NASA launches its first artificial satellite Telstar.

Answer 28

1962

Question 29

HDTV (high-definition television) was introduced in Japan.

Answer 29

1970

Question 30

Bob Kahn and Vint Cerf invented TCP (transmission control protocol).

Answer 30

1972

Question 31

Robert Metcalfe invents Ethernet to wire local computers together, and Martin Cooper of Motorola invented the first practical mobile phone.

Answer 31

1973

Question 32

First commercial use of optical fiber cables.

Answer 32

1977

Question 33

Internet development and first use.

Answer 33

1982

Question 34

AT&T opened the first commercial cellular telephone system in the United States.

Answer 34

1983

Question 35

Tim Burners-Lee invents the WWW (World Wide Web).

Answer 35

1991

Question 36

First browser Mosaic.

Answer 36

1993

Question 37

Global Positioning System deployed.

Answer 37

1995

Question 38

First smartphones by BlackBerry, Nokia, and Palm.

Answer 38

1996

Question 39

First WLANS (wireless local area networks).

Answer 39

1997

Question 40

DTV (digital television) transmission begins in the United States.

Answer 40

1999

Question 41

First fourth-generation LTE (long-term evolution) cellular networks and first 100 Gbps fiber optical networks.

Answer 41

2009

Question 42

Source of information. Performs encoding and modulation

Answer 42

Transmitter

Question 43

M - modulation the signal A - provides power to signal O - provides carrier signal

Answer 43

Modulator, amplifier, oscillator

Question 44

Destination of information. Performs decoding and demodulation

Answer 44

Receiver

Question 45

D - Demodulates signal A - provides power O - devices such as speaker, monitor, etc.

Answer 45

Demodulator (detector), amplifier, output devices

Question 46

Path or medium, which info travels unto. Attenuation (power loss) happens here

Answer 46

Transmission channels or medium

Question 47

Electronic circuit for increasing signal magnitude or amplitude w/o altering signal

Answer 47

Amplifier

Question 48

Produces periodic waveform with DC supply voltage as input. Non-rotating device to produce AC. Can be thought of as an ampli that provides itself (feedback)

Answer 48

Oscillator

Question 49

Parallel resonant circuit. Used at high frequency.

Answer 49

LC oscillator Note: RC oscillators are simpler, have lower cost, and are more suited for digital logic applications. LC oscillators are primarily used for higher-frequency applications, offer greater stability, and produce cleaner, nearly sinusoidal waveforms with fewer harmonics. They are commonly used in RF applications.

Question 50

H oscillator - tapped coil as feedback Co oscillator - split capacitor Cl oscillator - addtl capacitor in series Ar oscillator- tickler or transformer coil

Answer 50

Hartley Colpitts Clapp Armstrong

Question 51

USES RC networks for regenative feedback. Used for low frequencies

Answer 51

RC oscillator *Note: The impedance of an RC filter approaches R as the frequency enters the pass band. The impedance of an LC filter approaches 0. So an RC filter will always be an attenuator while the ideal LC filter is not.

Question 52

W B - oscillator- a sinusoidal feedback uses lead-lag circuit P S- series of RC sections Cr - output are highly stable and very precise frequency

Answer 52

Wien Bridge oscillator Phase shift oscillator Crystal oscillator

Question 53

● Frequency selective circuit. Passes or rejects frequency. ● Simple filters constructed by RC or LC are? ● Special filters that uses RC w/ feedback opamp circuit... can use DSP

Answer 53

Filters, passive filters, active filters

Question 54

Types of filter circuits: LP - passes frequency below cutoff or critical frequency and attenuate above cutoff HP- passes above but rejects below cutoff frequency BP - passes frequency over narrow range between lower and upper cutoff BR - rejects frequency over narrow range but allows frequency above and below to pass AP - passes all equally but has phase shift characteristics

Answer 54

Low pass, high-pass, bandpass, band reject, All-pass

Question 55

●Number of times a phenomenon occurs in a period of time. ●1 positive alteration and 1 negative alteration = ?

Answer 55

Frequency (Hz), 1 cycle

Question 56

defined as a single-valued function of time that conveys information

Answer 56

Signal

Question 57

time-varying voltages or currents that are continuously changing such as sine and cosine waves. Electrical signals of which amplitude changes continuously with respect to time with no breaks or discontinuities. Voice and video voltages

Answer 57

Analog signals

Question 58

voltages or currents that change in discrete steps or levels. Electrical signals amplitude maintains constant level for a prescribed period of time and then it changes to another level with respect to time with no breaks or discontinuities. Most digital signals use binary or two-state codes.

Answer 58

Digital signals

Question 59

frequency range over which information signal is transmitted or over which a receiver or other circuits operates

Answer 59

Bandwidth

Question 60

Known as cutoff, -3dB, breakup points

Answer 60

Half power points

Question 61

Fundamental quantity for rate at which energy is used. Can be converted to heat

Answer 61

Power

Question 62

Form of external noise when info signals from one source produce frequency that falls outside their allocated bandwidth and affects another source

Answer 62

Interference

Question 63

●Most common type of noise. ●Can noise be fully eliminated? ●Noise can be reduced by?

Answer 63

Thermal noise, no only minimize, reducing bandwidth

Question 64

●Used to determine the degree of intelligibility of a received signal ●Used to determine how much SN deteriorates as signal passes thru ●previous answer in dB

Answer 64

Signal to noise ratio, noise factor, noise figure