高通RF Calibration 介紹課件

RFCalibrationIntroduction高通RFCalibration介紹AgendaWhatisRFcalibration.Whycalibration.NVitemsofRFcalibration.RxCalibration.TxCalibration.高通RFCalibration介紹WhatisRFcalibration?RFcalibrationistheprocessofmeasuringdatatobeusedinthe systemforthepurposeofcompensationofnon-linear characteristicsandfrequencyvariations,andtoprovideabsolute powerreferenceandtemperaturecompensationtoensure performanceoftheTxandRxpathsofasubscriberunit.?Outputfromthecalibrationprocessisstoredinnon-volatile(NV) memoryitemsinAMSS.?AMSSusescalibrationvaluesduringnormaloperationtoensure systemperformanceismet.高通RFCalibration介紹Setup:WhatisRFcalibration高通RFCalibration介紹WhycalibrationSubscriberunitshavedifferingRFcharacteristicsDifferencesindesignPart-to-partvariationsofcomponentsofthesamedesign高通RFCalibration介紹IndividualphonesalsochangetheirownRFcharacteristics:

overfrequencychannelovertemperatureWhycalibration高通RFCalibration介紹WhycalibrationThesubscriberunitmustestimatetheRxpowerproperlyto maximizesignal-to-noiseratiosandtoprovideabasisforTx poweroutput.ThesubscriberunitmusttransmitatcorrectTxpowerlevelover itslargedynamicrange.TheMobileStationModem?(MSM?)deviceandsystemsoftware combinationmustknowtheRFandanalogcharacteristicsofthe particularunit.FailuretocompensatefordifferingRF/analogcharacteristicsmay causetheunittofailminimumperformancespecifications高通RFCalibration介紹Thecompensationvaluesareclassified:StaticRFNVitems:Measuredonceperdesign.CalculatedRFNVitems:RFNVitemsthatarecalculatedbasedonotherparametersofthedesignconfigurations.MeasuredRFNVitems:IsdeterminedbytheRFcalibrationprocess.NVitemsofRFcalibration高通RFCalibration介紹RxcalibrationPhilosophyofRxAGC(AutomaticGaincontrol)loop.DVGA(DigitalVGA)offsetcalibration.LNA(LowNoiseAmplifier)offsetcalibration.高通RFCalibration介紹Rxcalibration(RxAGCloop)EachRxchainhasitsownreceiver.?ReceivercalibrationprimarilyconsistsofmeasuringtheDVGAoffset(also calledVGAgainoffset)andmultipleLNAoffsets,allateachchosen frequencyindex.?Softwareloadsthefrequency-compensatedDVGAandLNAoffsetvaluesinto thehardwareregistersshownabove.高通RFCalibration介紹PhilosophyofRxDVGAoffsetcalibration:Rxcalibration(DVGAoffset)高通RFCalibration介紹Rxcalibration(LNAoffset)PhilosophyofRxLNAoffsetcalibration:高通RFCalibration介紹Rxcalibration(LNAoffset)高通RFCalibration介紹TxcalibrationPhilosophyofTxAGC(AutomaticGaincontrol)loop.TxLinearizerTxCompensationHDET(Highpowerdetector)高通RFCalibration介紹Txcalibration(AGCLoop)ThetransmitterAGCmustadjusttheTxpowerlevelbasedontheRSSI,accessprobeparameters,closed-looppower-controlbits(PCBs),andchannel-configurationattributes.高通RFCalibration介紹Txcalibration(AGCLoop)高通RFCalibration介紹Txcalibration(TxAGCCharacteristic)高通RFCalibration介紹Txcalibration(TxLinearizer)高通RFCalibration介紹Txcalibration(TX_GAIN_CTRL.)高通RFCalibration介紹Txcalibration(HDETFeedbackloopop.)高通RFCalibration介紹Txcompensation(1/3):NV_BCy_TX_COMP0_I~NV_BCy_TX_COMP3_INV_BCy_TX_COMP0_I=CDMA_TX_COMP_VS_FREQ[15:0]+ CDMA_TX_LIN_VS_TEMP[7:0]+ CDMA_TX_SLP_VS_TEMP[7:0]

Txcalibration(TxComp.)高通RFCalibration介紹CDMA_TX_LIN_VS_TEMP[7:0]:-UsedtoshifttheeffectiveTx-linearizercurvebyaconstantfortemperature-basedgainchanges.Forexample:Giventemperatureindex,theelementinthistableis0x05,eachofthe36offsetsintheadjustedmastercurvetablewillbeincreasedbyfive,whenthetemperaturecorrespondstothatgivenindex.CDMA_TX_SLP_VS_TEMP[7:0]

-UsedtoshifttheeffectiveTx-linearizercurvebyagraduatedamountfortemperature-basedgainchanges.Ps.typicallyallzerosunlessextraprecisionisdesired.Txcalibration(TxComp.)高通RFCalibration介紹High-powerdetector(HDET)(1/5):1.OutputatthepowerleveldefinedbyTX_GAIN_CTL.2.TheHDETcircuitmeasurestheoutputpower.3.TheHDETvalueissampled.4.TablethatmapstheHDETvaluetoTxpowerlevel.TheHDET’sestimatedpowerleveliscomparedtoTX_GAIN_CTLtodetermineanerrorvalue.TX_GAIN_LIMITisadjustedbythaterrorvalue.Note:OnlythemaximumpowerlimitisaffectedbytheHDETcircuit.

Txcalibration(TxHDET)高通RFCalibration介紹HDET(2/5):NV_BCy_TX_LIM_VS_FREQ_I:TheADCreadingsoftheHDETcircuitmayhavesomefrequencydependencies,thisNVitemcanbeusedtocompensateforsuchdependenciesTxcalibration(TxHDET)高通RFCalibration介紹HDET(4/5):NV_BCy_EXP_HDET_VS_AGC_I:AMSSusesthisNVitemtobuildalookuptable,whichindexesTxpowerestimationviaascaledTX_GAIN_CTL(representingthedesiredTxpower),totheassociatedHDETcircuitvaluesatreferencetemperatureandthereferencefrequency.Procedure:Breakuptheupper1/4ofTX_GAIN_CTLinto16segments.VarythedesiredTxpowerbymanipulatingtheTX_AGC_ADJPDM.ReadthevalueoftheHDETcircuitovereachofthe16segmentsandstoretheresultsinNV_BCy_EXP_HDET_VS_AGC[15:0]