Digital signal

Introduction

Theinformationagehascomewithoutnotice.Wearesurroundedbyvarioussignalsallthetime.Theessenceofthesignalisthephysicalquantitythatrepresentsthemessage(information),suchascommonInthesinusoidalelectricalsignal,ifitisdifferentamplitude,differentfrequency,ordifferentphase,itmeansdifferentmessages(information).Thedatawiththesignalasthecarriercanrepresentanyinformationintherealphysicalworld,suchastextsymbols,images,etc.Fromitsspecificmanifestation,thesignalcanbedividedinto:analogsignalanddigitalsignal.

Digitalsignalreferstotheuseofasetofspecialstatestodescribethesignal.Thetypicalsignaliscurrentlyrepresentedbythemostcommonbinarynumber.ThefundamentalreasonwhythebinarynumberisusedtorepresentthesignalisthatthecircuitonlyItcanrepresenttwostates,namelytheonandoffofthecircuit.Inactualdigitalsignaltransmission,acertainrangeofinformationchangesareusuallyclassifiedasstate0orstate1.Thesettingofthisstategreatlyimprovestheanti-noisecapabilityofthedigitalsignal.Notonlythat,intermsofconfidentiality,anti-interference,transmissionquality,etc.,digitalsignalsarebetterthananalogsignals,anditsavessignaltransmissionchannelresources.

Thedifferencebetweendigitalsignalanddiscrete-timesignalliesinthedependentvariable.Theindependentvariableofthediscrete-timesignalisdiscreteandthedependentvariableiscontinuous.Theindependentvariableisrepresentedbyaninteger,andthedependentvariableisrepresentedbyanumbercorrespondingtothesizeofthephysicalquantity.Afterthesizeofthediscrete-timesignalisrepresentedbyafinitebinarynumber,itisadigitalsignal.

Advantages

Therearemanyadvantagesofdigitalsignal.Firstofall,ithasaparticularlystronganti-interferenceability.Itcanbeusednotonlyincommunicationtechnology,butalsoininformationprocessingtechnology.ItisfashionableHigh-definitionTV,VCD,DVDlasermachinesallusedigitalsignalprocessingtechnology.Secondly,theelectroniccomputersweusearealldigital,andthesignalstheyprocessareoriginallydigitalsignals.Theuseofdigitalsignalsincommunicationsmakesiteasytocombinecomputerswithcommunicationsandusetheadvantagesofcomputersininformationprocessingforcommunications.Forexample,aprogram-controlleddigitalswitchisusedintelephonecommunication,andcomputersareusedtoreplacetheoperator'swork.Notonlyistheconnectionfastandaccurate,butitalsooccupiesasmallareaandishighlyefficient.Itsavesalotoflaborandequipment,whichmakestelephonecommunicationaqualitativeleap.Thirdly,digitalsignalsareeasytostore.NowpopularCDs,MP3discs,VCDs,DVDvideodiscsandcomputerdiscsallusedigitalsignalstostoreinformation.Inaddition,digitalcommunicationcanalsobecompatiblewiththetransmissionofmultipletypesofinformationsuchastelephone,telegraph,data,andimages,andcantransmitmultipletypesofinformationsuchastelephone,cableTV,andmultimediaonthesameline.Thedigitalsignalisalsoconvenientforencryptionanderrorcorrection,withstrongconfidentialityandreliability.

Becausethedigitalsignalusestwophysicalstatestorepresent0and1,itsabilitytoresisttheinterferenceofthematerialitselfandenvironmentalinterferenceismuchstrongerthanthatoftheanalogsignal;inthesignalprocessingofmoderntechnology,thedigitalsignalSignalsareplayingmoreandmoreroles,andalmostcomplexsignalprocessingcannotbeseparatedfromdigitalsignals;inotherwords,aslongasthemethodofsolvingproblemscanbeexpressedbymathematicalformulas,computerscanbeusedtoprocessdigitalsignalsthatrepresentphysicalquantities.

Indigitalcircuits,thedigitalsignalhasonlytwostates:0and1.Itsvalueisjudgedbythecentralvalue.Belowthecentralvalue,itisdefinedas0,andtheaboveisdefinedas1,soevenifitismixedForotherinterferencesignals,aslongasthevalueoftheinterferencesignaldoesnotexceedthethresholdrange,theoriginalsignalcanbereproduced.Evenifthevalueoftheinterferencesignalexceedsthethresholdrangeandtheerroroccurs,itiseasytodetectandcorrecttheerrorsignalaslongasacertaincodingtechnologyisadopted.Therefore,comparedwiththeanalogsignal,thedigitalsignalhasmoreadvantagesinthetransmissionprocess.Highanti-interferenceability,longertransmissiondistance,andsmalldistortion.

Digitalsignalsnotonlyhavehighanti-interferenceperformanceduringtransmission,butalsocanbecompressedtooccupylessbandwidth,andachievethetransmissionofmoreandhighervideoandotherdigitalsignalsinthesamebandwidth.Effect.Inaddition,digitalsignalscanalsobestoredinsemiconductormemoryanddirectlyusedforcomputerprocessing.Iftheimage,text,videoandotherdataprocessedbytelephone,fax,TVandothervariousformsofsignalsareconvertedintodigitalpulsesfortransmission,itisalsoconducivetoformingaunifiedcommunicationnetwork,realizingtoday’speoplefromallwalksoflifeandtelecommunicationsindustryWestronglyrecommendIntegratedServicesDigitalNetwork(IS-DN).Soastoprovidepeoplewithbrandnew,moreflexibleandmoreconvenientservices.Preciselybecauseoftheoutstandingadvantagesofdigitalsignals,itisrapidlyandhasbeenwidelyused.

Conversionbetweenanalogsignalanddigitalsignal

Analogsignal

Analogsignalwaveformsimulationchangeswiththechangeofinformation,andthecharacteristicofanalogsignaliscontinuousamplitude(Themeaningofcontinuousisthatanunlimitednumberofvalues​​canbetakenwithinacertainrangeofvalues).Analogsignal,itssignalwaveformisalsocontinuousintime,soitisacontinuoussignal.ThesampledsignalaftertheanalogsignalissampledatacertaintimeintervalT,becauseitswaveformisdiscreteintime,buttheamplitudeofthissignalisstillcontinuous,soitisstillananalogsignal.Telephone,fax,andtelevisionsignalsareallanalogsignals.

Afterthesignalissampled,thetimeisdiscrete,buttheamplitudeisnotdiscrete.Commonsamplingsignalsareperiodicrectangularpulseandperiodicimpulsepulsesampling.Theanalogsignalisdefinedontheentiretimeaxis,andthemeaningofthe"noamplitude"areaisthattheamplitudeiszero.Discretetimesignalsareonlydefinedatdiscretemoments.Theyarenotdefinedelsewhere.Itisadifferentconceptfromzeroamplitude.Thesetwosignalslooksimilaronthetimeaxis,buttheyareactuallybasedondifferenttypesofsystems.Thiskindofsignalisfundamentallydifferent.Intuitivelyspeaking,thehorizontalaxisofthediscretetimesignalcanberegardedasnolongerrepresentingtime.

Analogsignaltodigitalsignal

Theconversionofanalogsignaltodigitalsignalrequiresfourbasicsteps:signalsampling,signalholding,signalquantizationandsignalencoding.

Samplingistodiscretethecontinuoussignalintime,thatis,collecttheinstantaneousvaluepointbypointontheoriginalanalogsignalaccordingtoaspecifictimeinterval.Fromtheeffectpointofview,thehigherthesamplingfrequency,thecloserthediscretesignalobtainedistotheoriginalanalogsignal,butthehigherthesamplingfrequency,thehighertherequirementsfortheactualcircuit,whichwillalsobringalotofcalculationandstorage.Ifthesamplingfrequencyistoolow,itwillcauselossofinformation.Aftertakingitsinstantaneousvalue,itshouldbekeptintheoriginalpositionforaperiodoftime,sothattheformedsawtoothwavesignalisprovidedforsubsequentsignalquantization.

Toquantizethecollecteddiscretesignalistoconvertthesignalofaspecificamplitudeintoanintegermultipleofthesmallestunitoftheanalog-to-digitalconverter.Thissmallestunitisalsocalledthequantizationunitoftheanalog-to-digitalconverter.Eachsampledvaluerepresentstheinstantaneousamplitudeoftheanalogsignalobtainedbyonesample.Usuallythequantizationunitisamultipleof2.Themorequantizationbits,thesmallerthequantizationerror,andthebettertheresultofquantization.Intheactualquantizationprocess,approximateprocessingisrequired,sotheremustbeaquantizationerror.Thiserrorwillbereproducedinthefinaldigital-to-analogconversion.Thiserrorisusuallycalledquantizationnoise.Thisquantizationerrorcanusuallybereducedbyincreasingthenumberofquantizationbits,butwhenthesignalamplitudeisreducedtoacertainvalue,thecorrelationbetweenthequantizationnoiseandtheoriginalanalogsignalbecomesmoreobvious.

Encodingthequantizeddiscretesignalisthefinalstepofconvertinganalogsignalsintodigitalsignals.CommonlyusedparallelcomparisoncircuitsandsuccessiveapproximationcircuitsareusedtoconvertthequantizeddiscretesignalsintocorrespondingDigitalsignal.

Digitalsignaltoanalogsignal

Theconversionofdigitalsignaltoanalogsignaliseasiertounderstand.Infact,thedigital-to-analogconversioncanberegardedasdecodingadigitalsignal.Thedigital-to-analogconversionconvertstheinputbinarynumberintothecorrespondinganalogquantityaccordingtoitsactualweight,andthenaddstheanalogquantitycorrespondingtoeachdigit.Thetotalanalogquantityobtainedisproportionaltotheinputdigitalquantity,whichrealizestheconversionfromdigitalsignaltoanalogsignal.

Relatedtechnology

Digitalsignalprocessorisaprofessionalsignalprocessingequipment.Itsendsthecollectedrawdatasignaltothedigitalsignalprocessor.Throughsignalfiltering,samplingprocessinganddigitalsignaltransmission,thesignalconversionisrealizedaccordingtoactualneeds.Thissignalprocessingtechnologyiswidelyusedinmedicalandhealth,automationengineering,radardetection,aerospaceandotherfields.Intheprocessofcontinuousdevelopmentofscienceandtechnology,digitalsignaltechnologyhasbeenfavoredbyenterprises.Theproductsandtechnologieswithitasthecoreplayanirreplaceableroleinelectronicinformationengineering.

Features

Digitalsignalprocessingtechnologyextractssignaldata,filtersoutvalidandinvalidinformation,andfinallyconvertsthevalidinformationintoamoresuitablesignalform,makingthesignalmorestableandaccurate.Theprevioustechnologymainlyusesanalogsignals,butthismethodmakesitdifficulttomodifythedataparametersandthesignalsensitivityisnothigh.Indigitalsignaltechnology,binarylogictechnologyisused.Thistechnologyhasstrongperceptionandadaptabilitytotemperatureandcolorchanges.Bettersignalinputandoutput.

Advantages

Largescopeofapplication:Digitalsignalprocessingtechnologyiswidelyusedinvariousfieldsandhasawiderangeofapplicability.Digitalsignalprocessingtechnologycanbeappliedinmanyfields,becausetherearemanytypesofdigitalsignalprocessors,whichcanbeusedbyvarioussoftware,andcanalsobeselectedaccordingtodifferentneeds.Whenoperatorsstoredatainadigitalprocessingsystem,theycaneasilyconvertvariousinformationprocessingintotherequiredform.Takecomputernetworktechnologyasanexample.Incomputers,digitalsignalscanbeusedasamodulationprocessortechnology.,Applydigitalsignalprocessingtechnologytoprogramprogramming.

Fastprocessingspeed:Comparedwithanalogsignalprocessors,digitalsignalprocessorshaveobviousadvantagesinhigh-speedprocessing.Thechipofthedigitalsignalsimulatoritselfisquitedifferentfromotherchips.ItmainlyadoptstheHarvardstructure.Theprofessionalofelectronicengineeringcanseparatethedigitalinformationprogramandthestoragespacetoensurethatthetwodonotinterferewitheachotherandformadigitalsignalprocessor.Workflow.Comparingthedigitalsignalprocessingsystemwiththetraditionalsignalprocessing,thedigitalsignalcanberecognizedandprocessedwithotherinstructionsduringtheprocessingprocess,whichgreatlyimprovestheefficiencyofinformationprocessingandincreasesthespeed.

Developmentprospects

Withthedevelopmentanduseofdigitalsignalprocessingtechnology,overtime,theefficiencyandperformanceofdigitalsignalprocessingtechnologyhasbeencontinuouslyimproved.Withitsownuniqueadvantages,digitalsignalprocessingtechnologyhasgraduallybeenwelcomedbyelectronicproducts,andhasalsoreplacedthecoretechnologythatoncereacheditspeak,andhasachieveddevelopmentandimprovementinthisfield.Thecurrentuseofdigitalsignalprocessingtechnologyisinitsinfancy.Inthefuturedevelopment,thelevelofdigitalsignalprocessingtechnologywillcontinuetoimproveinpractice.Accordingtothecharacteristicsandadvantagesofdigitalsignalprocessingtechnologyandthefieldsthathavebeenenteredanddevelopedatpresent,thefuturedevelopmentofdigitalsignalprocessingtechnologywillmainlybereflectedinthefollowingaspects.Firstofall,digitalsignalprocessingtechnologywillpaymoreattentiontospeed,reducethelossofelectronicequipmentfunctionsandresources,reducegeometricdimensions,sothatdigitalsignalprocessingtechnologycanmeettheneedsofmodernsocietyandindustry.Thedemandintheproductionsectorcontinuestogrow.Secondly,thedevelopmentofdigitalsignalprocessingtechnologywillfocusontheimprovementandchangeofthecorestructure,andmorefocusontheapplicationofthecoremicro-architectureofthedigitalsignalprocessor.