无线电接收机英文资料及中文翻译

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1、------------------------------------------------------------------------------------------------无线电接收机英文资料及中文翻译英文资料及中文翻译RadioReceiverAblockdiagramforamodernradioreceiverisshowninFig..2-4.Theinputsignalstothisradioareamplitude-modulatedradiowaves.Thebasicelectroniccircuit

2、sinclude:antenna,tuner,mixer,localoscillator,IFamplifier,audiodetector,AFamplifier,loudspeaker,andpowersupply.Fig.2-4ABlockDiagramForModernRadioReceiverAnyantennasystemcapableofradiatingelectricalenergyisalsoabletoabstractenergyfromapassingradiowave.Sinceeverywavepassing

3、thereceivingantenna.Inducesitsownvoltageintheantennaconductor,itisnecessarythatthereceivingequipmentbecapableofseparatingthedesiredsignalfromtheunwantedsignalsthatarealsoinducingvoltagesintheantenna.Thisseparationismadeonthebasisofthedifferenceinfrequencybetweentransmitt

4、ingstationsandiscarriedoutbytheuseofresonantcircuits,whichcanbemadetodiscriminateverystronglyinfavorofaparticularfrequency.Ithasalreadybeenpointedthat,bymakingantennacircuitresonanttoaparticularfrequency,theenergyabstractedfromradiowavesofthatfrequencywillbemuchgreaterth

5、antheenergyfromwavesofotherfrequencies;thisalonegivesacertainamountofseparationbetweensignals.Still——————————————————————————————————————------------------------------------------------------------------------------------------------greaterselectiveactioncanbeobtainedbyt

6、heuseofadditionalsuitablyadjustedresonantcircuitslocatedsomewhereinthereceiverinsuchawayastorejectallbutthedesiredsignal.Theabilitytodiscriminatebetweenradiowavesofdifferentfrequenciesiscalledselectivityandtheprocessofadjustingcircuitstoresonancewiththefrequencyofadesire

7、dsignalisspokenofastuning.Althoughintelligibleradiosignalshavebeenreceivedfromthestationsthousandsofmilesdistant,usingonlytheenergyabstractedfromtheradiowavebythereceivingantennamuchmoresatisfactoryreceptioncanbeobtainedifthereceivedenergyis1amplified.Thisamplificationma

8、ybeappliedtotheradio-frequencycurrentsbeforedetection,inwhichcaseitiscalledradio-frequencyamplification