Problem of Measurements in Noisy Environments

8/4/2019 Problem of Measurements in Noisy Environments

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Verification of UWB RF

omp ance

noisy environments

JRC

Beijing, 20th November 2009


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Noiseanditssources

Measurementmet o s

UWBmeasurementso C a enges

o Setups

Conclusions


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Natural:

o erma no se

o Cosmicnoise

o Absorptionnoise

o Shotandflickernoise

Manmade:o Electromagneticinterference(EMI)

o Electromagneticpulses(EMP)


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65dBm/MHz*

97dBm/MHz*

Source: ETSI TR 102 273-1-1 V1.2.1

z

*at1mdistance


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Internal: External:

LocalOscillatornoise

(phasenoise)

o Cosmic/atmospheric

Amplifiernoise

o Thermalnoise

P=k T B

o seNoise

Noise Noise

Measurement

antenna

LNA Spectrumanalyzer


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Conducted

o Preferredmethod

Nominalimpedances

Improvedsensitivityofmeasurement

Reducedmeasurementuncertainty

Integralantennas/antennacharacteristics

DetectionofRFleaks/spuriousemissions

Radiatedo Useofantennas

Calibratedmeasurementantennasrequired

o Requiresdedicatedtestfacilities(complex,expensive)

Semi orfullyanechoicchamber,OTA,MAPS

o

Separationdistances

Calibrationofantennas

o Pathloss

Variesoverfrequencyrange


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Maintasks:

o er ca ono ev ces con ormance o mas s

o VerificationofUWBdevicescompliancewithmitigation

mechanismparameters


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Challenge:Reliabledetectionofverylowpowersignals

o x: rans on rom . m o m ncaseo opera ng

zonechange

o Lowestsignallevelis 90dBm

o Incaseofradiatedmeasurements,freespacepathlossbetween

equipmentundertest(EUT)andmeasurementantennareducessignal

o Signalstobemeasuredshouldbe+6dBabovethenoisefloorofthe

instrumentation

o UWBsignallevelsof70dBm/MHzareconsideredthedetectionlimit*

* At 2.7 GHz/1 m distance. Source: ERA Technology Report 2006-01713 (Issue 2): Conducted and Radiated Measurements for Low Level UWB Emissions


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UWBPSDmask

[dB

m/MHz]

traldensit -40

-50

powerspe

-60

-70

im

umm

ea

-80

-90

Ma

3.1 3.4 3.8 4.2 4.8 6 8.5 92.71.6 10.6

Frequency [GHz]

Without mitigation

With mitigation


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ConsumerUWBdevicestypically Eveniftheydo,replacingan

thereforeconductedmeasure

mentsarenotpossible

significantlyalterthedevices

RFTxcharacteristics

Radiatedmeasurementsaretheonlywayforverifyinga

pro uct scomp ancew t regu at onsan stan ar s


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Measurementsetup

41.3to 90dBm/MHzG:40dB

NF:

1.6

dB

NF:21dB

1 2

0,4dB 0,4dB

LNA SpectrumanalyzerEUT

LowestTxlevel: 90dBm/MHzT erma no se eve : 114 Bm MHz

Tx= 90.4dBm/MHz,noiselevel= 114dBm/MHz,SNR=23.6dB1

2 Tx= 50.8dBm/MHz,noiselevel= 72dBm/MHz,SNR=21.2dB

Spectrumanalyzernoisefloor: 93dBm/MHz

=>TheUWBsignalcanbedetectedwithoutproblem


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Measurementantennas

o ormeasuremen sa ove z, recommen swavegu e orn

antennas,althoughlogperiodicsmaybeused,aswell(EN302065

v1.2.1)

Broadbandhornantenna Logperiodicantenna


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Broadbandhornantennas

o xamp e: c warz ec use y e

Frequencyrange:1 18GHz,Gain:616dBi


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Measurement

antennaLNA SpectrumanalyzerEUT

d1 d2

Farfieldcalculation

D=

D d1=4cmd2=28cm

f=4GHz

=7.49cm

a. themeasurementismadeintheantennafarfield Typicalmeasurementdistancesare3mand1m

D=273cm

b. D>5d1


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Farfielddistancecalculationbasedonthegivenantennaparameters

PL(D)=20log( )4 fD

c

UWBBG#1


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Antennagainisnotflatbutvariesbetween6and13dBi


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ea xs gna(minimumlevelsthataretobedetected)

30

40

50

60

70

80

90


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ReceivedUWBTxsignal(at3mdistance)40

SNR[dB]

30

MinimummeasurementDesired

measurement

10B]

marginmargin

10dB

0SNR

[ 6dB

0dB

10

Everythingbelowthisline

is buried in thermal noise

30

Farfieldconditionviolated

1,0 2,0 3,0 4,0 5,0 6,0 7,0 8,0 9,0 10,0 11,0

Frequency[GHz]


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SNR[dB]

30

MinimummeasurementDesired

measurement

10B]

marginmargin

10dB

0SNR

[ 6dB

0dB

10



30

Farfieldconditionviolated

1,0 2,0 3,0 4,0 5,0 6,0 7,0 8,0 9,0 10,0 11,0

Frequency[GHz]


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Backgroundnoise

o pur ousem ss on m smay e g er an max.s gna eve s

CISPR&FCCClassB(residentialITE):54dBV/m= 41.3dBm/Mhz

ITURSM.32910(CatB): 30dBm/MHzforf>1GHz

o Example:PC

equ pmen may e n egra e n o os equ pmen

Notebook

UWBequipmentcanonlyfunctionincombinationwithahost

PCcard

USBdongle


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UWBTxmask

Spuriousemissions

measuredin1m

distance

gna n

1mdistance

GraphbasedondatafromTDKRFSystems


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UWBdynamicrange:~49dB(41.3dBmto 90dBm)

Lowestsignalleveltobedetected: 90dBm

Requiredreceiversensitivity: 96dBm -41 dBm

-114 dBm

1 2 3

Spectrum

2

-41 dBm

Path loss: 53 dB

D = 3 m

na yzer

Example:3.5GHzo

Pathloss(3m):~53dB -114 dBm

-94 dBm

SNR: 20 dB

o Min.UWBTxlevel: 90dBm

o Requiredsensitivity: 96dBm -82 dBmAntenna gain: 12 dB

-94 dBm

o :

o Thermalnoiselevel: 114dBmo =>23dBofSNRmustbegained

-114 dBm

SNR: 32 dB3


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ThereareseveralwaystoincreasetheSNR

o IncreaseTxsignalpower

Direct=AmplifyTxsignal n rect= e ucemeasurement stance

o Reducelinkloss

Reducemeasurementdistance


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Increaseantennagain

o a n an ennas ze

Increaseoffarfielddistance=increaseofpathloss

o Hi her ainbroadbandantennast icall cover

smallerfrequencyranges

MultipleantennasneededtocoverUWBrange(1)

Reducemeasurementdistance

o ear e measuremen s

o Smallformfactorwidebandantennas

Planarbroadbandantennas Cavitybackedspiralantennas

(3)

Size:35mmx39,5mm

(2)

Size:35mmx25mm

12 ource: 312 zWITHRIDGEDGROUNDPLANEC.C.LinandH.R.Chuang,DepartmentofElectricalEngineeringNationalChengKungUniversity,TainanProgressInElectromagneticsResearch,PIER83,307321,2008

3 ource: n oJXTXLX40804~8GHzBroadbandSpiralAntennaTestreport

magesource: cen e o r guez, . .,

AntennaSelectionforAutomotiveEMC

EmissionsandImmunityApplications(100

kHzto18GHz),Directory&DesignGuide

2005


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Hypotheticalmeasurementantenna(size:4cm,gain:0dBi)o Farfielddistance:25cm(3.1 4.8GHz)*

27

25

]

Referenceantenna

Smallsizeantenna

31

29

aoutput)[dB

35

33

Tx=>antenn

39

37

kb

udget(EU veragega n:~9

43

Lin

3,1 3,2 3,3 3,4 3,5 3,6 3,7 3,8 3,9 4,0 4,1 4,2 4,3 4,4 4,5 4,6 4,7 4,8

Frequency[GHz]AssuminganEUTantennasizeof4cm**Assumingareferenceantannameasurementdistanceof3m


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SNR[dB]

30

Minimummeasurement

Desired

measurement

10B]

marginmargin

10dB

0SNR

[ 6dB

0dB

=9dB

10



30

1,0 2,0 3,0 4,0 5,0 6,0 7,0 8,0 9,0 10,0 11,0

Frequency[GHz]


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Measuringdistance3m

Dynamicrange:

~34dB


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Measuringdistance1m

Dynamicrange:

34dB

~43dB

Gaineddynamic

ran e


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Receivernoise

o seo ow oss, owno secomponen s

o Filtering

Ambientnoise

o Filteringo Spectralsubtraction

o Temperaturereduction


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Criticalcomponents

o

Highgain(>30dB)

LowNF(


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PROs

o e u c o no am en an par so rece verno se

o Improvedsystemstabilitybyeliminatinginterferingoutofband

signals

CONs

o Introducesadditionalloss

o Maysuppressspuriousemissions


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2dB

Noisereductioninrelationtoroomtem erature 2 0K

Noiseandtemperature

12dB-110

=114

-120

-

z]

-130

-125

er[dBm

/M

-140

-135

Noise

po

-145

-150

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300

Temperature [K]


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Receiverside

o s ngacryogen c a very ow empera urescanm n m ze e

receivernoiseleveltofractionsofadBabovethetheoreticalminimum

0.1 6GHzcryogenicLNA

operatingdownto20K


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Configurations

1Spectrum

analyzer

Spectrum

analyzer

RegularLNA

2

CryogenicLNA

pec rum

analyzer3

Spectrum

analyzer

CryogenicLNA RegularLNA

4


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Overallgain

Spectrum

Gain:12dBNF:21dB

41.3dBm

Gain: 1.4dB

93.9dBm

Overallgain: 10.6dBGain(excl.Antenna): 1.4dB

Overallnoisefigure: 22.3dB

SignalpoweratSA: 83.3dBm

SAnoisefloor: 93dBm

SNR: 9.7dB


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Overallgain

Gain:12dBNF:21dB

Spectrum

anal zer

Gain:40dB

NF:1.6dB

Gain: 1.4dBGain: 0.1dB93.9dBm

Overallgain: 50.5dBGain(excl.Antenna): 38.5dB

Overallnoisefigure: 1.7dB

SignalpoweratSAinput: 43.4dBm

.

SAnoisefloor: 93dBm

SNR: 30.3dB


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Overallgain

Gain:12dBNF:21dB

Gain:30/32dB

NF:1.0/0.4dB

Spectrum

anal zer

Gain: 1.4dBGain: 0.1dB93.9dBm

Overallgain: 40.5dB

Gain(excl.Antenna): 28.5dB

Overallgain: 42.5dB


Overallnoisefigure: 1.7dB Overallnoisefigure: 0.9dB

.

NoiselevelatSAinput: 83.7dBm

SAnoisefloor: 93dBm

.


SAnoisefloor: 93dBm

SNR: 30.3dB SNR: 31.1dB


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Overallgain

Gain:12dBNF:21dB

Gain:30/32dB

NF:1.0/0.4dB

Spectrum

analyzer

Gain:40dB

NF:1.6dB

Gain: 1.4dBGain: 0.1dB Gain: 0.1dB93.9dBm

Overallgain: 80.5dB


Overallgain: 82.5dB


Overallnoisefigure: 1.1dB Overallnoisefigure: 0.5dB

.


SAnoisefloor: 93dBm

.


SAnoisefloor: 93dBm

SNR: 30.9dB SNR: 31.5dB


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SpectrumAnalyzernoisefloor

Noisefloor: 93dBm


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Noisefloor,LNA2poweredon

Noisefloor: 74dBm


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Noisefloor,LNA1andLNA2poweredono LNA1temperature:+20 C

Noisefloor:~ 44dBm


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First&secondrun

o e ercoo ngon y:

o Peltier+CO2 cooling: 87.8 C


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Thirdrun


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UsingacryogenicLNAatverylowtemperaturescanminimize

theoreticalminimum

This,however,willnotreducethethermalnoisepresentatthe

inputandoutputofthemeasurementantenna

Inordertoachieveasignificantreductionofthethermalnoise

theentiremeasurementsetupincludingEUTwouldhavetobe

cooledtoverylowtemperatureswhichisnotfeasible


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Gain:Upto5dB


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Physicallimitsmakeitpracticallyimpossibletoverifythe

byregulatoryandstandardizationbodies

o Increasemeasurementantennagain(maintaindistance)

o Reducemeasurementdistance(maintainantennasize)

o

=>Conductnearfieldmeasurementso Reducemeasurementantennasize(reducemeasurementdistance)

Reducedpathlossoffsetsantennagainreduction

o Usinganumberofdifferentantennasmaybenecessarytocoverthe

entireUWBfre uenc ran ePragmaticsolutionandWALTERrecommendationtoETSI:

Ifitcannotbemeasured,itisconsideredcompliant


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ETSITR10227311V1.2.1ElectromagneticcompatibilityandRadiospectrum

Matters(ERM);ImprovementonRadiatedMethodsofMeasurement(usingtest

site)andevaluationofthecorrespondingmeasurementuncertainties;Part1:

Uncertaintiesinthemeasurementofmobileradioequipmentcharacteristics

ETSI EN 302 065 V1.1.1 Ultra WideBand UWB technolo ies for communication

purposes;HarmonizedENcoveringessentialrequirementsofarticle3.2ofthe

R&TTEDirective

theradiospectrumforequipmentusingultrawidebandtechnologyinaharmonisedmannerintheCommunity

y u : u

MeasurementsforLowLevelUWBEmissions

WALTERDeliverableD4.2WALTERreportonlimitationsoftestmethods

WALTERDeliverableD5.2WALTERNetworkedlaboratory.Operational

configuration


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Coordinator Presenter

FranckLeGall(inno)

[email protected]

DetlefFuehrer

[email protected]

+33492388418 +390332783056

http://www.walteruwb.eu


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Problem of Measurements in Noisy Environments

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