hertz



Basicintroduction

History

HeinrichRudolfHertz(1857~1894),aGermanphysicist,firstusedexperimentsin1887Theexistenceofelectromagneticwaveswasconfirmed,andapaperwaspublishedin1888.Hemadeagreatcontributiontoelectromagnetism,sotheHertz,theSIunitoffrequency,isnamedafterhim.

Electricity(voltageorcurrent)canbedividedintoDCandAC.Incommunicationapplications,alternatingcurrentisgenerallyusedforsignaltransmission.

Hertzexperimentsprovedthatelectromagneticwavesexist,andthepropagationspeedofelectromagneticwavesisequivalenttothespeedoflight.TheHertzexperimentsopenedupinnovativewaysforthedevelopmentofradioelectronictechnologiessuchasradio,radar,andtelevision.Hestudiedtheinfluenceofultravioletlightonsparkdischargeanddiscoveredthephotoelectriceffect.Hebelievedthatobjectscanreleaseelectronsundertheirradiationoflight.ThisdiscoverybecamethebasisforEinstein'stheoryoflightquantum.

Real-worldapplications

Hertz(hertz)isabbreviatedasHz.Thephysicalmeasurementunitoffrequencyreferstothenumberofperiodicfluctuationspersecond.ThemeasurementunitsofhighfrequencymainlyincludekHz(ie1000Hz),MHz(ie1000kHz),GHz(ie1000MHz),andTHz(ie1000GHz).

Frequencyisthenumberofrepetitions,cyclesorvibrationsofaperiodicprocessperunittime,usuallyexpressedbyf.

Radiofrequencyisusuallymeasuredinkilohertz(kHz)ormegahertz(MHz).

Thepassbandofsingle-modefiberis100GHz/km,andthepassbandofmultimodefibercanexceed10GHz/km.

Unitconversion

Internationalsystemofunitsnotationderivedunits

1kilohertz(kHz103Hz)=1000Hz

1MHz(MHz106Hz)=1000000Hz

1GHz(GHz109Hz)=1000000000Hz

1Terahertz(THz1012Hz)=1000000000000Hz

1BeatHz(PHz1015Hz)=1000000000000000Hz

1Ah(EHz1018Hz)=1000000000000000000Hz

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