射頻鏈路指標預(yù)算

射頻鏈路指標預(yù)算…目錄中頻盤鏈路構(gòu)成OIP3與NF計算公式發(fā)射通道鏈路預(yù)算反饋通道鏈路預(yù)算接收通道鏈路預(yù)算基本公式ACPR分析本振泄露分析DPD通道分析接收靈敏度分析阻塞與反混疊濾波器分析互調(diào)分析半中頻雜散分析LC濾波器設(shè)計濾波器帶寬要求中頻盤鏈路構(gòu)成OIP3與NF計算公式以兩階系統(tǒng)為例：發(fā)射通道鏈路預(yù)算G=10dB，NF=18.9，OIP3=31.5，Pout=-3.5PinTX-13.5DeviceGainNFIP3SGainSNFSIP3PoutLPF-11100-11100-14.5TRF37031112301223-13.5PI-55100-512.555428818-18.5RFFILTER-44100-913.5778651914-22.5PI-44100-1315.415986510-26.5BG18C15.54.5402.518.5176614225.34858-11HMC472-3335-0.518.5517219722.11891-14PI-33100-3.518.6188937319.11891-17BG18C15.54.5401218.855325133.51415-1.5PI-221001018.8574106631.51415-3.5反饋通道鏈路預(yù)算G=-15.5dB，NF=33.5，OIP3=33.8，Pout=0PinCP15.5DeviceGainNFIP3SGainSNFSIP3PoutHMC472-171735-171735-1.5HMC349-1149-181833.86479-2.5HMC485-9940-272724.73366-11.5LPF-11100-282823.73366-12.5PI-11100-292922.73366-13.5BIF3164.540-1333.536.310542.5LPF00100-1333.536.310542.5PI-11100-1433.5100105635.310541.5ETC412-1.51.5100-15.533.530020533.810530接收通道鏈路預(yù)算G=54.5dB，NF=3.21，OIP3=34.3PinRX-125DeviceGainNFIP3SGainSNFSIP3PoutLNA3033030330-95PI-22100283.00127290928-97HMC485-9940193.02515252418.96564-106LPF-11100183.03220093517.96564-107PI-22100163.05218304315.96564-109BIF3205.240363.1752821634.51999-89HMC4720035363.1752821631.74307-89SAWFILTER-101010026374307-99PI-3310023374307-102BIF3205.240433.20931746636.31592-82pxv1220s-33100403.20942092933.31592-85BIF3205.240603.20990030539.80218-65LPF-11100593.20990084238.80218-66PI-33100563.20990344135.80218-69ETC412-1.51.510054.53.2099055934.30218-70.5基本公式系統(tǒng)ACPR=RFPower–熱噪聲–NF-信號底噪–最大非線性產(chǎn)物接收靈敏度=熱噪聲+NF+SNR–處理增益OIP3=RFPower+IMD3/2，IMD3=RFPower–最大非線性產(chǎn)物最大非線性產(chǎn)物=RFPower–2*(OIP3-RFPower)OIP3=IIP3+G，IIP3=RFPower(Input)+IMD3/2(Input)接收系統(tǒng)串聯(lián)IIP2=2*RFPower+Pr=RFPower+IMR2IMR2=RFPower-PrACPR分析1.DAC時鐘相噪對DAC輸出信號底噪的貢獻：-145-20lg(737.28M/140M)=-159.43dBm/Hz2.DAC輸出信號的總底噪：-159.43+(-158)=-155.58dBm/Hz3.3.84M帶寬的擴頻增益：10lg3.84M=65.84dB4.DAC在發(fā)射通道輸出口的總噪聲：-155.58+65.84+10=-79.74dBm/3.84MHz5.發(fā)射通道輸出口的總熱噪聲：-174+65.84+10+18.86=-79.3dBm/3.84MHz6.發(fā)射通道輸出口的信號底噪：-79.3+(-79.74)=-76.5dBm/3.84MHz7.發(fā)射通道輸出口的最大非線性產(chǎn)物：-3.5–2*(31.5+3.5)=-73.5dBm8.發(fā)射信號的ACPR：[-76.5+(-73.5)]–(-3.5)=-68.2ACPRanalysisLOGorFMAGNITUDEKTB-1743.98107E-18SAMPLECLK(M)737.28

BW3840000

IF(M)140

CLKNOISE-145

DACNOISE-1581.58489E-16CLKTODACNOISE-159.431.14023E-16DACOUTPUTNOISE-155.5832.76493E-16BWGAIN65.84331

DACNOISEFLOOR-89.73981.06173E-09CHANNELNF18.86

CHANNELGAIN10

CHANNELOIP331.5

SIGNALPOWER-3.5

SIGNALNoise-79.73981.06173E-08KTBNoise-79.29671.17579E-08SIGNALNF-76.50232.23753E-08CHANNELOIP3TOACPR-70

MAXP3rd-73.54.46684E-08TotalCHANNELNoise-71.73646.70436E-08CHANNELMAXACPR-68.2364

本振泄露分析1.功放口的本振泄露：-35+10+50-35=-10dBm2.共站時腔體濾波器所需抑制度：-10–(-86)=76dBLOleakageLOGorFIQleakage-35TXchannelgain10PAgain50RFfilter35PAleakage-10coexistrequirement-86Cavityfilter76DPD通道分析1.進入ADC的熱噪聲：-174+65.84+33.5-15.5=-90.16dBm/3.84MHz2.進入ADC的最大非線性產(chǎn)物：0–2*(33.8+0)=-67.6dBm3.ADC的底噪：4–66–10lg(92.16M/3.84M)=-75.8dBm/3.84MHz4.反饋信號進入ADC后所能達到的最大ACPR：[-90.16+(-67.6)+(-75.8)]–0=-66.97DPDanalysisLOGorFMAGNITUDECHANNELNF33.5

CHANNELGAIN-15.5

CHANNELOIP333.8

SIGNALPOWER0

KTBNF-90.1567

NFTOACPR-90.15679.64564E-10OIP3TOACPR-67.61.7378E-07ADCFSPower4

ADCSNR66

ADCNF-75.80212.62899E-08CHANNELMAXACPR-66.96732.01035E-07接收靈敏度分析1.WCDMA靈敏度測試使用的是單載波3.84M帶寬。2.處理增益：10lg(3.84M/12.2k)=25dB3.4.5M的熱噪聲：-174+10lg3.84M=-108.16dBm/3.84MHz4.接收靈敏度：-108.16–25+3.2+6=-123.96dBm/3.84M(協(xié)議要求低于-121dBm)RSSIanalysisLOGorFMAGNITUDEKTB-174

BW3840000

BWGAIN65.84331

NF3.2

KTB3.84MBW-108.157

KTBNF-104.957

ProcessGain25

SNR6

ReceiveSensitivity-123.957

阻塞與反混疊濾波器分析1.當有大阻塞信號進入時，為了使ADC不溢出，混頻器與小功率放大器有更好的線性表現(xiàn)，上行DCA增益是需要衰減的。衰減后整個上行的噪聲系數(shù)為5.5。2.熱噪聲：-174+10lg3.84M+5.5=-102.66dBm/3.84M3.除去熱噪后可接受的總噪聲：-96–(-102.66)=-97.06dBm4.帶內(nèi)反混疊濾波器所需要的抑制度：-35–(-97.06)=62.06dB5.考慮到上行通道的平坦度，以及阻塞大信號進入上行通道后所引起的非線性效應(yīng)，需要再保留3dB。帶內(nèi)反混疊濾波器所需要的抑制度：62.06+3=65dB6.帶外阻塞信號為-15dBm，所以對于帶外阻塞信號反混疊濾波器所需要的抑制度：-15-（-97.06）+3=85.06dBBlockanalysisLOGorFMAGNITUDEBLOCKSIGNAL-353GPP=-40dBWantedSINGAL-115

SNR6

ProcessGain25

AcceptableMAXnoise-962.51189E-10ChannelNF5.5

KTB-174

3.84MBWKTBwithNF-102.6575.42414E-11TotalNoise-97.05651.96947E-10FilterRestriction62.0565

互調(diào)分析1.在天線口除去熱噪聲后最大可接受的噪聲：-97.06dBm2.假設(shè)互調(diào)產(chǎn)物占50%：-97.06–3=-100.06dBm3.輸入IIP3：-48+[-48–(-100.6)]/2=-21.97dBm4.輸出OIP3：-21.97+50=28.03dBm互調(diào)信號相對于靈敏度信號依然是大信號，所以上行通道也需要做適當?shù)乃p，這樣可以降低上行通道OIP3的要求，節(jié)約器件成本。IP3analysisLOGorFMAGNITUDEWantedSINGAL-115

SNR6

ProcessGain25

AcceptableMAXnoise-962.51189E-10KTBIN3.84MBW-102.6575.42414E-11MAXNoiseexceptKTB-97.05651.96947E-10IMproduct-100.057Assume50%CHANNELGAIN50

3GPP-48dBm-48

IIP3-21.9717

OIP328.02825

半中頻雜散分析1.半中頻雜散：頻率為IF/2+Flo，經(jīng)過混頻器下變頻以后會進入中頻不會被混頻器以后