intro to wired

8/9/2019 Intro to Wired

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ECE 433Wired Communications



Week # Topics

1 Fundamental of wire communications, History of wire

communications and evolution of technology

2 Nature and characteristics of sound, Sound and Speech

parameters

3 Telegraphy

4 Telephony

5 Signaling, management of trunk and local loop, The rotary and

pulse dialing techniques

6 Basic CPE, Types of transmitters, receivers and microphones

7 MTE

8 Basic Element of Telephone Networks and Outside Plant facilities

and architecture

9 Plant Switching facilities and techniques

10 PSTN Value Added Services (VAS), ISDN, DSL and systems



Week # Topics

11 Mobile telephone, Cordless phone, Marine and radio mobile

telephony, Introduction to Analog transmission, NMT, AMPS,

etc., Analog multiplexing

12 Introduction to Digital coding and Multiplexing

The PCM, MMS, SMS, and other VAS, Introduction to CDMA,

GSM, Third Generation Phone (3G), video transmission over the

telephone

13 Other wire systems of communicationsCATV, TVRO, and CCTV systems

14 ETE



Evolution of Telephone

System1876

February 14,Alexander GrahamBell submits a patentapplication or!!impro"ement intele#raphy,$$ %hichresults in the %orld$s

&rst telephonepatent' ()arch 1*,Bell calls !!)r'Watson, come here, +%ant you' Bell’s first telephone



1877

First permanenttelephone line isinstalled bet%eenBoston and omer"ille,

)assachusetts' -disonde"elops the carbontelephone transmitter'

iemens . /als0e start

telephone production inGermany' Manual exchange used in Germany

around 1900



1878

)anual telephone s%itchboard operates in e%/a"en, Connecticut'

utt starts as the &rst %oman telephone operator' Bell 2elephone Company opens telephone ser"ice

in 3ondon'

3ouis(Francois Bre#uet starts telephoneproduction in aris'



1881

+nternational telephoneoperation starts bet%een

5etroit in the nitedtates and Windsor,ntario, in Canada'

1886 tro%#er Company

de"elops the telephone(dialin# dis0

189

tro%#er telephoneexchan#e operates in 3aorte, +ndiana

Telephon of Reis, 1863:left, the receiver; right, the transmitter.



Wall telephone, 1888.Luxury table telephone used by the

Vatican, 1900



11:

e% ;or0<anFranciscotelephone lineopens usin#

telephoneampli&ers'

=ohn G' >obertsand =ohn '>eynolds obtainthe &rst patent orcrossbar s%itchin#' Inauguration of the New

York–Chicago telephone lineby A.Graham Bell onOctober 18, 1892



19:

CC+2 ?Consultati"e Committee +nternational on

2ele#raphy@ and CC+F ?Consultati"e Committee+nternational on 3on# 5istance 2elephony@ areounded'

196 2he &rst crossbar s%itch is installed at unds"all,

%eden

197''<'' intercontinental radiotelephony be#ins'



16

Bristol<lymouth, '', lon#(distance cable carries19 multiplexed telephone channels

16*

-lectronic telephone exchan#e is installed in)orris, +llinois'

17*

5i#ital s%itchin# be#ins operation in 3annion,France'

(''<'' intercontinental direct dialin# be#ins



17

Cellular radio be#ins operation in =apan'

115i#ital cellular radio ?G)@ be#ins operation in

Finland'



Elements of Electronics

Communications-lectronics Communications ystem < transerinormation rom one place to another'

-lectronics Communication < transmission,reception, and processin# o inormation bet%eent%o or more locations usin# electronic circuits'

• 2he ori#inal source inormation can be in analo#orm such as the human "oice or music, or in

di#ital orm such as binary(coded numbers oralphanumeric codes'



SOUND• ound is de&ned as any pressure "ariation that

the ear can detect ran#in# rom the %ea0estsounds to sound le"els %hich can dama#ehearin#'

• 2he study o sound is called ACOUSTICS andco"ers all &elds o sound production, soundpropa#ation and sound reception, %hether

created and recei"ed by human bein#s or bymachines and measurin# instruments'



Physics of Sound• ound can propa#ate throu#h compressible

media such as air, %ater and solids aslon#itudinal %a"es and also as a trans"erse%a"es in solids'

• 2he sound %a"es are #enerated by a soundsource, such as the "ibratin# diaphra#m o astereo spea0er'

• 2he sound source creates "ibrations in the

surroundin# medium'• As the source continues to "ibrate the medium,

the "ibrations propa#ate a%ay rom the source atthe speed o sound, thus ormin# the sound %a"e'



• At a &xed distance rom the source, the pressure,

"elocity, and displacement o the medium "ary intime'

• At an instant in time, the pressure, "elocity, anddisplacement "ary in space'

•

2he beha"ior o sound propa#ation is #enerallyaDected by three thin#sE

A relationship bet%een density and pressure' 2his

relationship, aDected by temperature, determinesthe speed o sound %ithin the medium'



2he propa#ation is also aDected by the motion o

the medium itsel' For example, sound mo"in#throu#h %ind' +ndependent o the motion osound throu#h the medium, i the medium ismo"in#, the sound is urther transported'

2he "iscosity o the medium also aDects themotion o sound %a"es' +t determines the rate at%hich sound is attenuated' For many media, suchas air or %ater, attenuation due to "iscosity isne#li#ible'



Sound Waves Properties

and Characteristics• Freuency

• Wa"elen#th

• Wa"e umber

• Amplitude

• ound ressure

• ound +ntensity

•

peed o ound• 5irection



• ound that is perceptible by humans hasreuencies rom about 20 Hz to 20,000 Hz.

• +n air at standard temperature and pressure, thecorrespondin# %a"elen#ths o sound %a"es ran#erom 17 m to 17 mm.

• ometimes speed and direction are combined asa "elocity "ector %a"e number and direction arecombined as a %a"e "ector'



Speed of Sound

• 2he speed o sound depends on the medium thatthe %a"es pass throu#h, and is a undamentalproperty o the material'

• 2he &rst si#ni&cant eDort to%ards the measure othe speed o sound %as made by e%ton'

• /e belie"ed that the speed o sound in aparticular substance %as eual to the suare rooto the pressure actin# on it ?2@ di"ided by itsdensity'



• 2his %as later pro"en %ron# %hen ound toincorrectly deri"e the speed'

• French mathematician 3aplace corrected theormula by deducin# that the phenomenon osound tra"elin# is not isothermal, as belie"ed bye%ton, but adiabatic'

• 2hose physical properties and the speed o soundchan#e %ith ambient conditions'

• For example, the speed o sound in #asesdepends on temperature' +n 9* HC ?68 HF@ air at

sea le"el, the speed o sound is approximately4 mIs ?1,9* 0mIh 767 mph@ usin# the ormulaJ" K ?1 L *'6 2@ mIsJ'



• +n resh %ater, also at 9* HC, the speed o soundis approximately 1,489 mIs ?:,: 0mIh,1: mph@'

• +n steel, the speed o sound is about :,6* mIs?91,46* 0mIh 1,* mph@'



Did you know that?

Mero dB(3 < threshold o hearin#

1* dB(3 < sound o lea"es rustlin#

19*(14* dB(3 < sound produced by Net en#ine

19* dB(3 < threshold o pain

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