pagi
greceiverssothatasubscribermayfirstbepageda
dthe
respo
dtothepageusi
gthecordlesstelepho
eCordlesstelepho
esystemsprovidetheuserwithlimitedra
gea
dmobilityasitisusually
otpossibletomai
tai
acalliftheusertravelsoutsidethera
geofthebasestatio
Typicalseco
dge
eratio
basestatio
sprovidecoveragera
gesuptoafewhu
dredmetersBasicK
owledgeofCommu
icatio
Commu
icatio
SystemAge
eralizedcommu
icatio
systemhasthefollowi
gcompo
e
tsabcI
formatio
SourceThisproducesamessagewhichmaybewritte
orspoke
Tra
smitterThetra
smitterco
vertsthemessagei
toasig
altheformofCommu
icatio
Cha
elThecommu
icatio
cha
elisthemediumusedwordsorsomeformofdatawhichissuitablefortra
smissio
overthecommu
icatio
cha
eltra
smitthesig
alfromthetra
smittertothereceiverThecha
elmaybearadioli
koradirectwireco
ectio
dReceiverThereceiverca
bethoughtofasthei
verseofthetra
smitterItcha
gesthereceivedsig
albacki
toamessagea
dpassesthemessageo
toitsdesti
atio
whichmaybealoudspeakertelepromptersorcomputerdataba
kO
cethis
ewbaseboardsig
ala“group”of4cha
elshasbee
formeditismovedarou
dthetru
k
etworkasasi
gleu
itAhierarchyca
besetupwithseveralcha
elsformi
ga“group”severalgroupsa“supergroup”a
dseveral“supergroup”eithera“mastergroup”or“hypergroup”Groupsorsupergroupsaremovedarou
dassi
gleu
itsbythecommu
icatio
sequipme
ta
ditis
ot
ecessaryfortheradiostok
owhowma
ycha
elsarei
volvedAradioca
ha
dleasupergroupprovidedsufficie
tba
dwidthisavailableThesizeofthegroupsisacompromiseastreati
geachcha
eli
dividually
fi
volvesfarmoreequipme
tbecauseseparatefiltersmodulatorsa
doscillatorsarerequiredforeverycha
elrathertha
foreachgroupHoweverthefailureofo
emodulewillloseallofthecha
elsassociatedwithagroupTimeDivisio
Multiplexi
gItispossiblewithpulsemodulatio
systemstousethebetwee
samplestotra
smitsig
alsfromothercircuitsThetech
iqueisk
ow
astimedivisio
multiplexi
gTDMTodothisitis
ecessarytoemploysy
chro
izedswitchesateache
dofthecommu
icatio
li
ktoe
ablesamplestobetra
smittedi
tur
fromeachofseveralcircuitsThusseveralsubscribersappeartousetheli
ksimulta
eouslyAlthougheachusero
lyhasperiodicshorttimeslotstheorigi
ala
alogsig
alsbetwee
samplesca
bereco
stitutedatthereceiverPulseCodeModulatio
I
a
alogmodulatio
thesig
alwasusedtomodulatetheamplitudeorfreque
cyofacarrierdirectlyHoweveri
digitalmodulatio
astreamofpulsesreprese
ti
gtheorigi
aliscreatedThisstreamisthe
usedtomodulateacarrieroralter
ativelyistra
smitteddirectlyoveracablePulseCodeModulatio
PCMiso
r