網(wǎng)絡(luò)分析儀測(cè)試基本概念與工作原理

1、page 1page 2page 3雙功器LO LC 濾波器功分器TX IF LC濾波器耦合器隔離器平衡/非平衡轉(zhuǎn)換混頻器LNA放大器SAW 濾波器SAW 濾波器天線射頻前端模塊平衡/非平衡轉(zhuǎn)換page 4 Lightwave入射入射反射反射透射透射 RF/MWpage 5 Gain, Phase, Group delay VSWR, , , Impedancel 工作頻率工作頻率; 信號(hào)功率信號(hào)功率page 6 dB全匹配全匹配(ZL = Zo) RLVSWR01全反射全反射 (ZL = 開路開路,短路短路 )0 dB1=ZL-ZOZL+OZ=V反射V輸入=F= -20 log(),VSWR

2、 = EmaxEmin=1 + 1 - EmaxEmin (功率比值功率比值)page 7 0+R+jX-jXRectilinear impedance plane.-90o0o180o+-.2.4.6.81.090o 0 0等電抗圓等電抗圓等電阻圓等電阻圓Smith Chart 圓圖上圓圖上 一點(diǎn)一點(diǎn)位置反映對(duì)應(yīng)的位置反映對(duì)應(yīng)的阻抗阻抗(R+jx)和和反射反射(模和相位模和相位)LZ = 0=180 O1(短路點(diǎn)短路點(diǎn)) Z = L=0 O1(開路點(diǎn)開路點(diǎn)) Z = ZoL= 0大電阻區(qū)大電阻區(qū)小電阻區(qū)小電阻區(qū)電感區(qū)電感區(qū)電容區(qū)電容區(qū) Z=R+jx Z=R+jx page 8RL / RSR

3、SRLRL = RS: 負(fù)載上最大功率傳輸負(fù)載上最大功率傳輸 Zs = R + jXZL = Zs* = R - jX ZL = ZS* (共軛匹配共軛匹配)RL / RS00.20.40.60.811.2012345678910Load Power (normalized)page 9V傳輸V輸入傳輸系數(shù)傳輸系數(shù) = T T=VTransmittedVIncident = tf tfDUT增益增益 (dB) = 20 Log VTrans VInc = 20 log t t插入損耗插入損耗 (dB) = - 20 Log VTrans VInc = - 20 log t tpage 10Ti

4、meAtoFrequencyf1TimeSin 360 * f * tFrequencyA phase shift = to * 360 * f1fDUT A * Sin 360 * f ( t - t )輸入輸入輸出輸出TimeFrequencyf1page 11系統(tǒng)頻率帶寬內(nèi)幅頻特性為常量系統(tǒng)頻率帶寬內(nèi)幅頻特性為常量MagnitudePhaseFrequencyFrequency系統(tǒng)頻率帶寬內(nèi)相頻特性為線性系統(tǒng)頻率帶寬內(nèi)相頻特性為線性 V = a f( t - to)輸出輸出V = f(t)輸入輸入DUTpage 12網(wǎng)絡(luò)分析儀相位補(bǔ)償網(wǎng)絡(luò)分析儀相位補(bǔ)償+=Frequency(Electr

5、ical delay )FrequencyPhase 1 /DivoPhase 45 /DivoFrequency 應(yīng)用應(yīng)用: 測(cè)量器件相位特性 難于定量分析相位特性線性 應(yīng)用應(yīng)用: 便于對(duì)相位特性線性的分析網(wǎng)絡(luò)分析儀的相位補(bǔ)償處理功能：網(wǎng)絡(luò)分析儀的相位補(bǔ)償處理功能： page 13in radiansin radians/secin degreesf in Hertz (w = 2 p f)fwfGroup Delay (t )g =-d fd w=-1360od fd f*Frequency群時(shí)延抖動(dòng)群時(shí)延抖動(dòng)平均時(shí)延平均時(shí)延totg PhasefDfFrequencyDwwpage 14

6、PhasePhaseGroup DelayGroup Delay- -d f fd w w- -d f fd w wffffpage 15TransmittedIncident傳輸特性傳輸特性增益增益S參數(shù)參數(shù)S21,S12群延時(shí)群延時(shí)Delay傳輸系數(shù)傳輸系數(shù)相位相位PhaseReflectedIncident反射特性反射特性SWRS參數(shù)參數(shù)S11,S22反射系數(shù)反射系數(shù)阻抗阻抗 R+jX, G+jB 反射損耗反射損耗 , , T,tT,t輸入輸入反射反射輸出輸出RBAAR=BR=page 16S11=ReflectedIncident=b1a1a2= 0S21=TransmittedInc

7、ident=b2a1a2= 0S22=ReflectedIncident=b2a2a1= 0S12=TransmittedIncident=b1a2a1= 0輸入輸入傳輸傳輸S21S11反射反射b1a1b2Z0Loada2= 0DUT正向正向輸入輸入傳輸傳輸S12S22反射反射b2a2ba1= 0DUTZ0Load反向反向1S-parameters 電壓線性值定義電壓線性值定義page 17FrequencyFrequencyTimeTimepage 18CH1 S21 1og MAG 1 dB/ REF 32 dB 30.991 dB 12.3 dBmC2 IF BW 3 kHz SWP 4

8、20 msecSTART 5 5dBm CW 902 MHz STOP 15 dBm1 dB compression point: 輸入功率增加導(dǎo)致器件增益下降輸入功率增加導(dǎo)致器件增益下降1dBl相對(duì)測(cè)試相對(duì)測(cè)試l輸出輸出1dB壓縮點(diǎn)壓縮點(diǎn)(絕對(duì)測(cè)試絕對(duì)測(cè)試) 測(cè)試功率測(cè)試功率 測(cè)試頻率測(cè)試頻率01dB 輸入輸入1dB壓縮點(diǎn)壓縮點(diǎn)page 19飽和工作電平飽和工作電平壓縮工作區(qū)壓縮工作區(qū)線性工作區(qū)線性工作區(qū) (slope = small-signal gain)1dBpage 20AmplitudeTimeAM (dB)PM (deg)Mag(AMin)Test StimulusAmplitu

9、deTimeAM (dB)PM (deg)Mag(AMout)Mag(PMout)Output ResponseAM - PM Conversion =Mag(PMout)Mag(AMin)(deg/dB)DUTPower sweepIQAM to PM conversion can cause bit errors輸入功率對(duì)器件相位特性的影響輸入功率對(duì)器件相位特性的影響page 21Port 2功率分配/開關(guān)源R1APort 1R2B衰減器衰減器測(cè)量接收機(jī)參考接收機(jī)參考接收機(jī)反射信號(hào)(A)傳輸信號(hào)(B)輸入信號(hào)輸入信號(hào)輸出信號(hào)輸出信號(hào)DUT信號(hào)源信號(hào)源信號(hào)分離裝置信號(hào)分離裝置接收機(jī)接收機(jī)處理

10、顯示單元處理顯示單元RAB輸入源輸入源LO 源源RFN*LO +/- IF反射反射傳輸傳輸輸入?yún)⒖夹盘?hào)輸入?yún)⒖夹盘?hào)輸入信號(hào)輸入信號(hào)輸出信號(hào)輸出信號(hào)BRARl提供被測(cè)件激勵(lì)信號(hào)提供被測(cè)件激勵(lì)信號(hào)l具備具備頻率和功率掃描頻率和功率掃描功能功能l合成源實(shí)現(xiàn)合成源實(shí)現(xiàn)頻率合成源頻率合成源ALCALCDriverALC 檢測(cè)檢測(cè)衰減器衰減器源源ALC = 自動(dòng)電平控制自動(dòng)電平控制 (automatic level control)l功分器功分器提供參考信號(hào)提供參考信號(hào)寬頻率覆蓋寬頻率覆蓋6 dB50 W50 W6 dBl定向耦合器定向耦合器l電橋電橋方向性方向性低插入損耗低插入損耗Main signal

11、Coupled signalRECEIVER / DETECTORPROCESSOR / DISPLAYREFLECTED(A)TRANSMITTED(B)INCIDENT (R)SIGNALSEPARATIONSOURCEIncidentReflectedTransmittedDUT 定向耦合器連接端點(diǎn)定向耦合器連接端點(diǎn): 反射特性測(cè)試點(diǎn)反射特性測(cè)試點(diǎn)Test PortDetector(入射信號(hào)泄漏入射信號(hào)泄漏)(被測(cè)件反射方向被測(cè)件反射方向)定向耦合器定向耦合器(定向耦合器輸入端定向耦合器輸入端)Data MaxAdd in PhaseDeviceDirectivityReturn Los

12、sFrequency03060DUT RL = 40 dBCancel Data 0DeviceDirectivityData = Vector SumDirectivityDeviceData Min 被測(cè)件反射信號(hào)被測(cè)件反射信號(hào)與定向耦合器泄漏的與定向耦合器泄漏的 輸入信號(hào)輸入信號(hào)在接收機(jī)端矢量疊加在接收機(jī)端矢量疊加 影響測(cè)試精度影響測(cè)試精度接收機(jī)類型Tuned ReceiverScalar broadband (no phase information)Vector(magnitude and phase)DiodeDCACRFIF FilterIF = F LOFRFRFLOADC /

13、 DSPRECEIVER / DETECTORPROCESSOR / DISPLAYREFLECTED(A)TRANSMITTED(B)INCIDENT (R)SIGNALSEPARATIONSOURCEIncidentReflectedTransmittedDUT300kHz8.5 GHz混頻器前端混頻器前端ADC / DSP幅度幅度+相位信息相位信息接收機(jī)帶寬接收機(jī)帶寬 :70kHz-100dBError Due to Interfering Signal0.0010.010.11101000-5-10-15-20-25-30-35-40-45-50-55-60-65-70Interfer

14、ing signal (dB)Error (dB, deg)phase errormagn error+-網(wǎng)絡(luò)分析儀測(cè)試精度與測(cè)試動(dòng)態(tài)范圍關(guān)系網(wǎng)絡(luò)分析儀測(cè)試精度與測(cè)試動(dòng)態(tài)范圍關(guān)系T/R vs S-Parameter Test SetslRF always comes out port 1lport 2 is always receiverlresponse, one-port cal availablelRF comes out port 1 or port 2lforward and reverse measurementsltwo-port calibration possibleTran

15、smission/Reflection Test SetPort 1Port 2SourceBRADUTFwdPort 1Port 2Transfer switchSourceBRAS-Parameter Test SetDUTFwdRevRECEIVER / DETECTORPROCESSOR / DISPLAYREFLECTED(A)TRANSMITTED(B)INCIDENT (R)SIGNALSEPARATIONSOURCEIncidentReflectedTransmittedDUTAB負(fù)載失配負(fù)載失配串?dāng)_串?dāng)_方向性誤差方向性誤差DUT頻率響應(yīng)誤差頻率響應(yīng)誤差l傳輸跟蹤誤差傳輸跟蹤誤差R 單端口共單端口共 6 項(xiàng)誤差項(xiàng)誤差 雙端口共雙端口共 12 項(xiàng)誤差項(xiàng)誤差 反射信號(hào)反射信號(hào)l S11MS11ASHORTOPENLOADthruthruSHORTOPENLOAD電子校準(zhǔn)件電子校準(zhǔn)件(Ecal)機(jī)械校準(zhǔn)件機(jī)械校準(zhǔn)件校準(zhǔn)件多次連接校準(zhǔn)件多次連接Shorts, Open, Loads, Thru單次連接；多端口校準(zhǔn)單次連接；多端口校準(zhǔn)Single Connection1.不校準(zhǔn)不校準(zhǔn) 2. 頻響校準(zhǔn)頻響校準(zhǔn) 3. 1-PORT單端校準(zhǔn)單端校準(zhǔn) 4. FULL 2-PORT雙端校準(zhǔn)雙端校準(zhǔn)l復(fù)雜,校準(zhǔn)件多次連接l高精度l消除測(cè)試中所有