Test bank for electronic communication systems by blake

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CHAPTERg1:gINTRODUCTIONgTOgCOMMUNICATIONgSYSTEMS

1. Itgmovesginformationgfromgagsourcegtogagdestinationgthroug Communicationg System
hgagchannel.



2. Elementsgofgagcommunicationgsystem
Source,gTransmitter,gCh
annel,gReceiver,gDestination

3. Threegessentialgelementsgofganygcommunicationgsystem Transmitter,gReceiver,gChannel

4. Sourcesgofginformationgsignals AnaloggandgDigital

5. Sourcesgaregoftengdescribedgingtermsgofgtheg FrequencygRange
gthatgtheygoccupy




6. Thegelementgofgagcommunicationgsystemgwhereingthegsignalgwill Transmitter
gbegdrivengoutgofgthegsourcegtogthegchannel.




7. Thisgelementgofgcommunicationgsystemgcangbegagpairgofgconductor Channel
sgorgangopticalgfibergorgthegfreegspacegwhereingthegsignalgisgtraveli
nggtogthegreceiver



8. Ingagfreegspacegchannel,g Carrier
signalgisgrequiredgtogavoi
dginterference.



9. Whengagcarriergisgused,gtheginformationgsignalgcangbegalsogcalle ModulatinggSignal
dgas
.



10. Sincegthegcarriergfrequencygisggenerallygmuchghighergthangthatgofgt Baseband
heginformationgsignal,gthegfrequencygspectrumgofgtheginformationgsi
gnalgisgoftengreferredgtogasg .



11. Modulationgisgdonegatgtheg . Transmitter
12. Thisgprocessgtakesgplacegatgthegreceivergwhereingthegsignalghasgtogbe
Demodulation
restoredgtogitsgoriginalgbasebandgsignal.
13. Itgstatesgthatgthegamountgofginformationgthatgcangbegtransmittedg
ingaggivengtimegisgproportionalgtogbandwidthgforgaggivengmodula Hartley’sgLaw
tinggscheme..

14. Itgrefersgtogthegcombininggofgtwogorgmoreginformationgsignals.
Multiplexing

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gFrequency-

Division
15. Methodsgofgmultiplexing. Multiplexing,
gTime-

Divisiong Multiplexing
16. Whengthegavailablegfrequencygisgdividedgamonggthegsignals,gthe Frequency-divisiong Multiplexing

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processgisgknowngasg .
17. Ingthisgprocess,gthegentiregbandwidthgisgusedgforgeachgsignal,gbutg
Time-Divisiong Multiplexing
onlygforgagsmallgpartgofgtime.
18. Itgisgthegavailablegbandwidthgofgagcommunicationgsatellitegdivi
Transponder
dedgamonggagnumbergofgtransmitter-receivergcombinations.


19.g Itgisganygundesirablegchangeginganginformationgsignal. Distortion
HarmonicgDistortion
,gIntermodulationgDistortion,gN
20.g Possiblegtypesgofgdistortion. onlineargFrequencygResponse,g
NonlineargPhasegResponse,
Noise,Interference

21. Agrepresentationgofgagsignal’sgpowergorgamplitudegasgagfunctio
FrequencygDomain
ngofgfrequency.


22. Agwaygofgrepresentinggthegperiodicgfunctionsgasgagseriesgofgsinusoids. FouriergSeries
23. Anygundesiredgdisturbancegthatgisgsuperimposedgongagsignalgand
Noise
obscuresgitsginformationgconten
t


24. Twogtypesgofgnoise. InternalgandgExternalgNoise
25. Noisegwhichgoriginatesgwithingthegcommunicationgequipment. InternalgNoise
26. Noisegoutsidegthegcommunicationgequipment. ExternalgNoise
27. Noiseggeneratedgbygequipmentgthatgproducesgsparks. EquipmentgNoise
28. Noisegthatgisgoriginatedgfromglightning. Atmosphericg Noise
29. Refergtogno.g28:ganothergnamegforgthisgkindgofgnoise Static
30. Noisegthatgcomesgfromgheavenlygbodiesgthatgaregpowerfulgsourcesgof
SpacegNois
radiation.
31. Thisgnoisegisgproducedgbygthegrandomgmotiongofgelectronsgi
egThermalgNoi
ngagconductorgduegtogheat.
32. Thisgisgduegtograndomgvariationsgingcurrentgflowgingactivegdevicesgs
segShotgNois
uchgasgtubes,gtransistors,gandgsemiconductorgdiodes.
33. NoisegthatgoccursgingthegpartitiongofgthegNegativegandgPositivegelem
e
entsgingagsemiconductorgsuchgasgBJT.

PartitiongNoise

34. Thisgnoisegisgcausegbygvariationsgingcarriergdensity. ExcessgNoise
35. Refergtogno.g34:ganothergnamegforgit. FlickergNoise,gPinkgNoise
36. Noisegthatgmanygjunctiongdevicesgproducegduegtogcut-offgfrequency
Transit-Timeg Noise
reaching.


37. ratiogofgsignalgtognoisegpowergatgaggivengpointgingagsystem. Signal-to-Noiseg Ratio

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38. Devicegforgdisplayinggsignalsgingthegfrequencygdomain. SpectrumgAnalyzer