射频链路指标预算

射频链路指标预算…目录中频盘链路构成OIP3与NF计算公式发射通道链路预算反馈通道链路预算接收通道链路预算基本公式ACPR分析本振泄露分析DPD通道分析接收灵敏度分析阻塞与反混叠滤波器分析互调分析半中频杂散分析LC滤波器设计滤波器带宽要求中频盘链路构成OIP3与NF计算公式以两阶系统为例：发射通道链路预算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反馈通道链路预算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接收通道链路预算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基本公式系统ACPR=RFPower–热噪声–NF-信号底噪–最大非线性产物接收灵敏度=热噪声+NF+SNR–处理增益OIP3=RFPower+IMD3/2，IMD3=RFPower–最大非线性产物最大非线性产物=RFPower–2*(OIP3-RFPower)OIP3=IIP3+G，IIP3=RFPower(Input)+IMD3/2(Input)接收系统串联IIP2=2*RFPower+Pr=RFPower+IMR2IMR2=RFPower-PrACPR分析1.DAC时钟相噪对DAC输出信号底噪的贡献：-145-20lg(737.28M/140M)=-159.43dBm/Hz2.DAC输出信号的总底噪：-159.43+(-158)=-155.58dBm/Hz3.3.84M带宽的扩频增益：10lg3.84M=65.84dB4.DAC在发射通道输出口的总噪声：-155.58+65.84+10=-79.74dBm/3.84MHz5.发射通道输出口的总热噪声：-174+65.84+10+18.86=-79.3dBm/3.84MHz6.发射通道输出口的信号底噪：-79.3+(-79.74)=-76.5dBm/3.84MHz7.发射通道输出口的最大非线性产物：-3.5–2*(31.5+3.5)=-73.5dBm8.发射信号的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.共站时腔体滤波器所需抑制度：-10–(-86)=76dBLOleakageLOGorFIQleakage-35TXchannelgain10PAgain50RFfilter35PAleakage-10coexistrequirement-86Cavityfilter76DPD通道分析1.进入ADC的热噪声：-174+65.84+33.5-15.5=-90.16dBm/3.84MHz2.进入ADC的最大非线性产物：0–2*(33.8+0)=-67.6dBm3.ADC的底噪：4–66–10lg(92.16M/3.84M)=-75.8dBm/3.84MHz4.反馈信号进入ADC后所能达到的最大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接收灵敏度分析1.WCDMA灵敏度测试使用的是单载波3.84M带宽。2.处理增益：10lg(3.84M/12.2k)=25dB3.4.5M的热噪声：-174+10lg3.84M=-108.16dBm/3.84MHz4.接收灵敏度：-108.16–25+3.2+6=-123.96dBm/3.84M(协议要求低于-121dBm)RSSIanalysisLOGorFMAGNITUDEKTB-174

BW3840000

BWGAIN65.84331

NF3.2

KTB3.84MBW-108.157

KTBNF-104.957

ProcessGain25

SNR6

ReceiveSensitivity-123.957

阻塞与反混叠滤波器分析1.当有大阻塞信号进入时，为了使ADC不溢出，混频器与小功率放大器有更好的线性表现，上行DCA增益是需要衰减的。衰减后整个上行的噪声系数为5.5。2.热噪声：-174+10lg3.84M+5.5=-102.66dBm/3.84M3.除去热噪后可接受的总噪声：-96–(-102.66)=-97.06dBm4.带内反混叠滤波器所需要的抑制度：-35–(-97.06)=62.06dB5.考虑到上行通道的平坦度，以及阻塞大信号进入上行通道后所引起的非线性效应，需要再保留3dB。带内反混叠滤波器所需要的抑制度：62.06+3=65dB6.带外阻塞信号为-15dBm，所以对于带外阻塞信号反混叠滤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

互调分析1.在天线口除去热噪声后最大可接受的噪声：-97.06dBm2.假设互调产物占50%：-97.06–3=-100.06dBm3.输入IIP3：-48+[-48–(-100.6)]/2=-21.97dBm4.输出OIP3：-21.97+50=28.03dBm互调信号相对于灵敏度信号依然是大信号，所以上行通道也需要做适当的衰减，这样可以降低上行通道OIP3的要求，节约器件成本。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

半中频杂散分析1.半中频杂散：频率为IF/2+Flo，经过混频器下变频以后会进入中频不会被混频器以后