红外物理层基础

Infraredlight,commonlyreferredtoas“IR”,isacom-

mon,easy-to-use,lowpowerandlow-costmediato

transmitinformation.Amongthefew“wireless”commu-

nicationchoices,IRhasthesignificantadvantageof

compatibilitywithhundredsofmillionsofelectronic

deviceswithIRports(i.e.,laptopPCs,PDAs).

ThevastmajorityofIR-capabledevicesarecompatible

withasetofstandardsestablishedbytheInfraredData

Association,orIrDA

®

.Thesestandardsincludeguide-

linesforimplementingtheIRPhysicalLayer(IrDA

SerialInfraredPhysicalLayerspecification),ensuring

thatIRcommunicationcanbeestablishedthroughfree

spacebetweentwodissimilardevices.

Thisdocumentdescribesthefundamentalsofthe

infraredphysicallayer,theIrDAstandardandselecting

theproperdiscreteemitterandphotodiode

componentsforcircuitimplementation.MAN243FundamentalsoftheInfraredPhysicalLayerTounderstandthesteradian,wewillfirstconsidertheAuthor:PaulBarnaradian.Theradianisdefinedastheangle‘a’thatMicrochipTechnologyInc.SteveSchlangerproducesanarc‘S’thatisequalinlengthtotheradius‘R’andisequalto360/2πdegrees(~57°17’46.6”).AegisTechnologiesLLCThearciscreatedby