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-1010100263.18000564421.74307-99PI-33100233.18522311918.74307-102BIF3205.240433.20931746636.31592-82pxv1220s-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+IMR2•IMR2=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/Hz•2.DAC输出信号的总底噪：-159.43+(-158)=-155.58dBm/Hz•3.3.84M带宽的扩频增益：10lg3.84M=65.84dB•4.DAC在发射通道输出口的总噪声：-155.58+65.84+10=-79.74dBm/3.84MHz•5.发射通道输出口的总热噪声：-174+65.84+10+18.86=-79.3dBm/3.84MHz•6.发射通道输出口的信号底噪：-79.3+(-79.74)=-76.5dBm/3.84MHz•7.发射通道输出口的最大非线性产物：-3.5–2*(31.5+3.5)=-73.5dBm•8.发射信号的ACPR：[-76.5+(-73.5)]–(-3.5)=-68.2ACPRanalysisLOGorFMAGNITUDEKTB-1743.98107E-18SAMPLECLK(M)737.28BW3840000IF(M)140CLKNOISE-145DACNOISE-1581.58489E-16CLKTODACNOISE-159.431.14023E-16DACOUTPUTNOISE-155.5832.76493E-16BWGAIN65.84331DACNOISEFLOOR-89.73981.06173E-09CHANNELNF18.86CHANNELGAIN10CHANNELOIP331.5SIGNALPOWER-3.5SIGNALNoise-79.73981.06173E-08KTBNoise-79.29671.17579E-08SIGNALNF-76.50232.23753E-08CHANNELOIP3TOACPR-70MAXP3rd-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=-10dBm•2.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/3.84MHz•2.进入ADC的最大非线性产物：0–2*(33.8+0)=-67.6dBm•3.ADC的底噪：4–66–10lg(92.16M/3.84M)=-75.8dBm/3.84MHz•4.反馈信号进入ADC后所能达到的最大ACPR：[-90.16+(-67.6)+(-75.8)]–0=-66.97DPDanalysisLOGorFMAGNITUDECHANNELNF33.5CHANNELGAIN-15.5CHANNELOIP333.8SIGNALPOWER0KTBNF-90.1567NFTOACPR-90.15679.64564E-10OIP3TOACPR-67.61.7378E-07ADCFSPower4ADCSNR66ADCNF-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)=25dB•3.4.5M的热噪声：-174+10lg3.84M=-108.16dBm/3.84MHz•4.接收灵敏度：-108.16–25+3.2+6=-123.96dBm/3.84M(协议要求低于-121dBm)RSSIanalysisLOGorFMAGNITUDEKTB-174BW3840000BWGAIN65.84331NF3.2KTB3.84MBW-108.157KTBNF-104.957ProcessGain25SNR6ReceiveSensitivity-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/3.84M•3.除去热噪后可接受的总噪声：-96–(-102.66)=-97.06dBm•4.带内反混叠滤波器所需要的抑制度：-35–(-97.06)=62.06dB•5.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=65dB•6.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-115SNR6ProcessGain25AcceptableMAXnoise-962.51189E-10ChannelNF5.5KTB-1743.84MBWKTBwithNF-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：-97.06dBm•2.假设互调产物占50%：-97.06–3=-100.06dBm•3.输入IIP3：-48+[-48–(-100.6)]/2=-21.97dBm•4.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-115SNR6ProcessGain25AcceptableMAXnoise-962.51189E-10KTBIN3.84MBW-102.6575.42414E-11MAXNoiseexceptKTB-97.05651.96947E-10IMproduct-100.057Assume50%CHANNELGAIN503GPP-48dBm-48IIP3-21.9717OIP328.02825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的模拟滤波器与数字数字滤波器滤除。•2.在天线口除去热噪声后最大可接受的噪声：-97.06dBm•3.针对半中频杂散所需的抑制度：16-（-97.06）=113.06•4.换算成串联IIP2：16+113.06=129.06dBm•5.系统串联IIP2=混频器IIP2–混频器前总增益+2*滤波器抑制度•6.对应的腔体滤波器抑制度要求：(129.06+28–39)/2=59.03dBHalfIFspuranalysisLOGorFMAGNITUDEInputHalfIFspur16MAXNoiseexceptKTB-97.0565IMR2113.0565SerialIIP2129.0565MixtureIIP239datasheetGainbeforeMixture28RequireFilterIMR259.02825LC滤波器设计LC滤波器设计LC滤波器设计LC滤波器设计滤波器带宽要求•DPD算法要求能够采集到5阶互调产物•发射通道的介质滤波器的带宽=5*信号带宽+协议规定的频率范围-信号带宽•反馈通道的带通滤波器的带宽=5*信号带宽附录Thankyouf