HP-PNE5100A-2_Crystal Resonator Measuring Functions Of HP E5100A-B Network Analyzer

8/14/2019 HP-PNE5100A-2_Crystal Resonator Measuring Functions Of HP E5100A-B Network Analyzer

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Introduction

Crystal resonators are employedin various types of equipment thatare in great demands in recent

years such as communicationsequipment, computers and automobile electronic controls. Theincreasing performance of equipment requires higherresonator performance. Forexample, communicationsequipment uses the resonator at alow drive level, so the basicoperation of the equipment isseriously affected by resonance

failure at a low drive level,resonance failure due to changesin the drive level and temperature

characteristics when used inautomobiles, and other similaroperation failures. As a result,stricter requirements are beingimposed on the measurement of resonant frequency, resistanceand equivalent circuit constants,and the detection of spurioussignals on each drive level. It has

become essential to ensureeffective and accurate

measurements of these factors.This Product Note introduces aneffective evaluation procedure forcrystal resonators based on theHP E5100A network analyzer.

Overview of the crystal measuringfunctions for E5100A networkanalyzer

Measuring frequency range: 10kHz to 300 MHz

Measurement drive level range:

-52 dBm to +18 dBm (option 600)

Measurement parameter: Amplitude, phase, group delay,impedance, admittance

Built-in high speed waveformanalysis functions

Options dedicated for crystalmeasurement (DLD andevapolation)

Built-in HP instrument BASICfunctions

3.5 -inch FDD, built-in RAM disk(DOS format)

Crystal Resonator MeasuringFunctions of HP E5100A/BNetwork Analyzer

Product Note E5100A-2E5100A/BNetwork Analyzer


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The following describes theoptional functions of theHP E5100A that provide aneffective resonator evaluation:

(1) Measurement of high speed drive level characteristics (Measurementby Option 023)

The crystal resonator drive levelcharacteristics have recentlygained in importance togetherwith stricter requirements forquick and accurate evaluation of characteristics. The followingintroduces an effective evaluation

method for the measurement of drive level characteristics, usingthe HP E5100A.

Current problems

Use of the Pi-network test fixtureis accompanied by excessive

signal damping because the output power level in the measuringinstruments is insufficient; thisresults in measurementdifficulties on drive levels of ashigh as 100 W.

Frequency sweep of evaluation of characteristics requires theresonant frequency andimpedance to be obtained byfrequency sweep on each drivelevel, as illustrated in Figure 1.

This results in longer overallmeasurement time, and hencereduced throughput.

The number of drive levels to beevaluated is restricted by thelimited measurement time,making it difficult to ensure

detailed drive level of theevaluation characteristics(multi-point evaluation).

Use of normal power sweep toreduce measuring time results inthe resonant frequencyundergoing changes in conformityto changes in drive level. Thismakes it difficult to ensureaccurate measurement of drivelevel characteristics.

In the measurement of a devicehaving a higher Q factor, the

phase of the frequency sweep islikely to deviate significantly from0 degree in comparison with thecase where the drive level ischanged. This causes devicefrequency sweep response to bedelayed, adversely affecting theoverall throughput.

2

Frequency

P1 P2 P3

|Z|

Figure 1. Drive level characteristics evaluation based on frequency sweep


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Solutions with the HP E5100A

The HP E5100A has a built-in power splitter. The level after

passing through the power splitterranges from -52 dBm through+18 dBm (option 600). Even whenusing the Pi-network test fixturefeaturing substantial signaldamping, the CI value is 25 ohms,and power up to a maximum of 1 mW can be applied to thedevice. This permits evaluationover a wide range, from a very lowto a very high level. Furthermore,use of the HP E5100A's phasetracking measuring function(Option 023) allows quick anddetailed drive level of theevaluation characteristics.

Overview of the phase trackingmeasuring function

The phase tracking measuring

function provides tracking toensure that the measurementsignal will reach the phase value(normally 0) of the specifiedresonance, thereby obtaining thefrequency and impedance at that

phase. Based on the measurementresult at the measuring point andthe information from the 3 dB

bandwidth of the device, the pointof 0 phase (the resonantfrequency) at that power and levelis predicted, and measurement isrepeated at the predictedfrequency to ensure tracking of the 0 degree phase. Figure 2illustrates the basic tracking

procedure.

3

START

|Z| - f Display

Within Limit?

Calculate Resonant Frequency

Tracking to Resonant Freq.

END

NO

N = 1

YES

|Z| - MeasurementN = N+1

|Z| - Measurement

YES

NOFail

N = NOP?

Figure 2. Flow of basic phase tracking functions


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This method allows the Fr andCI-values to be tracked while thedrive level is changed. Thiseliminates the need for frequency

sweeping at each drive level.Thus, the tracking measuringfunction permits the measurementof the deviation of resonantfrequency ( f) and the drive levelresonance impedance (|Z|)characteristics in one sweep, asshown in Figure 3. The referencefrequency of f is equal to theresonant frequency at the lowestdrive level, which makes it

possible to avoid the responsedelay resulting from changes inthe device due to frequency sweepin the measurement of drive levelcharacteristics of a device havinga high Q factor, and cuts downyour measurement time.

An example of measuring theactual drive levelcharacteristics

In the measurement of actualdrive level characteristics, theSRCHFR? command searches forresonant frequency at the drivelevel of the first of the drive levelcharacteristics after execution of

pi-calibration. The phase trackingmeasuring function obtains thedrive level characteristics in the

vicinity of the resonant frequency(See Figure 4). Figure 5 illustratesthe measurement of thecharacteristics in one sweep whenthe drive level is raised from 10nWto 10 W or lowered from 10 W to10nW.

Figure 4. Flow of drive levelcharacteristics measurement

4

|Z|- f

|Z|

Drive Level

NO-GO

GO

f (fr - fnom )

Nominal Frequency(fnom )

Figure 3. Drive level sweep by phase tracking function

START

Search Fr by SRCHFR?

END

Setup Measurement, Tracking, and Power List

Calibration

Measure Drive Level Dependency by Tracking


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Tracking measurement intemporal changes

The phase tracking measuring

function can be used to measuredrive level characteristics as wellas transient characteristics of thedevice responding toenvironmental changes. Forexample, when the device issubjected to abrupt changes intemperature from low to high inorder to measure steep transientchanges in resonant frequency andresistance of the device,measurement may not becompleted in time if frequencymust also be measured. This

problem is solved by the phasetracking measuring functionwhich ensures highly reliablemeasurement without missingabrupt changes in characteristics.Use of the phase tracking function

provides quick GO/NO-GOselection and detailed evaluationof the drive level characteristicsof the device.

5

Figure 5. An example of measuring drive level characteristics


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(2) Evaporation system control (Option 022)

In evaporation of a crystal

resonator, resonant frequency islowered and adjusted to thedesired level during silverdeposition. The evaporationsystem requires the amount of evaporated silver to be controlledwhile changes in resonantfrequency are measured duringevaporation. The frequency trapfunction of the HP E5100A(Option 022) ensures the quickmonitoring of changes in theresonant point, without using thenormal frequency sweep. Thisfunction allows real-timetransmission of the changes in theresonant frequency of the device,using control signals and provideshighly efficient control of theevaporation system.

Basic operation of thefrequency trap function in theevaporation process

With the start of evaporation, thedevice resonant frequency(frequency at phase 0) starts todecline from its resonantfrequency (f-START) prior toevaporation and approaches thetarget frequency (f-STOP), asillustrated in Figure . 6. In thiscase, as shown in Figure 7, the

phase value begins to exhibit agradual increase from around -90at the target frequency (f-STOP),and the phase becomes 0 whenthe device resonant frequency hasreached the target frequencyduring evaporation.

To adjust the device resonantfrequency to the target frequency,the HP E5100A continues phasemeasurement at the target

frequency from the start of adjustment. The systemdetermines that the targetfrequency is reached when the

phase has changed from anegative value to 0 at thatfrequency and sends the I/Ocontrol signal to the evaporationsystem to terminate evaporation.

Figure 7. Changes of phase at the targetfrequency during evaporation

6

Phase

FrequencyfstartfstopFigure 6. Behavior of the device resonant frequency during evaporation

0

Frequency

Phase

Time

Time

fstop


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An example of use in an actualevaporation system

As in the basic operation shown

above, where the evaporationcontrol consists of only on/off control, evaporation should beterminated if the phase hasreached 0 at the target frequency.In addition to such on/off controlin actual evaporation, however, itis possible to control thefrequency adjustment by thegradual reduction of the amountof deposited silver, as illustratedin Figure 8. This is made possible

by repeating the above procedure. A concrete example is given inFigure 9. The HP E5100Ameasuring frequency is set atmore than one point; it is set

between the frequency prior toadjustment and the targetfrequency, as well as at the finaltarget frequency. Phasemeasurement is carried outsequentially from the highestfrequency. When the phase of 0 ismeasured, the I/O signal is sentand the next frequency ismeasured; this process isrepeated.

7

f2

+90

-90

0

f1 f0

P 2 P 1P 3

f3

Phase

Frequency

Figure 8. Changes of device phase in evaporation control at more than one point

f0

f1f2

P 0 P 1 P 2

0

Frequency

Phase

Time

Time

I/O Output

Figure 9. Changes of HP E5100A measurement frequency and measurement phase inevaporation control at more than one point


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Additional HP E5100Afunctions andcharacteristics in crystal

device measurement(1) High speed measurementand analysis

List sweep function

This function permits the highspeed measurement of amaximum of 0.04ms/points. Inaddition, the list sweep function

provides high speed measurement by setting the measurement

segment only at the frequency andlevel required for measurement.Even when the measurementfrequencies are separated fromeach other, as, for example, insimultaneous evaluation of the

basic resonance and harmonics,this function permitsmeasurement of only frequenciesclose to the desired frequency andtheir effective measurement andanalysis.

High speed analysiscommand/resonance parameteranalysis

Crystal parameter analysisThis function provides a highspeed analysis of resonantfrequency (Fr) and resonanceresistance (CI value) at the phaseof 0 as basic parameters of thecrystal resonator, with a singlecommand.

Analysis of spurious levels(resistance)Spurious response may be presentas a specific characteristic of the

device. Generally, spurious occurswithin a frequency range of 10%of the resonant frequency.High-quality resonance circuits

can be designed only whenresistance of the circuit issufficiently higher than theresonance resistance at the

nominal resonant frequency. Thus,not only the CI value close to thenominal frequency but alsospurious level are sometimesevaluated to see if there is anyspurious effect. In this case, themeasurement shown in Figure 2 is

performed to confirm differencesin resistance between the two.The HP E5100A uses themaximum/minimum peak valuesanalysis function to provide highspeed evaluation of spurioussignal resistance and the CI value.

8

Resonant Frequency & Impedance (Fr,CI)

0

|Z| -

Frequency

Anti-Resonant Frequency & Impedance (Fa,Za)

Figure 10. High speed analysis of resonant frequency and resistance atthe phase of 0


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Equivalent circuit analysisfunction

The equivalent circuit constant aswell as the resonant frequencyand resistance of the device areimportant parameters inevaluating the characteristics of the device. Generally, the4-element equivalent circuitshown in Figure 3 is used as acrystal resonator equivalentcircuit. In practice, however,resistance is also present in theresonator lead and electrode;therefore, more accurate analysismay be ensured by the 6-elementequivalent circuit as given inFigure 4. Furthermore, if themeasurement data close to theresonant point is used to analyzethe parallel capacitance C0 as an

equivalent circuit parameter, acapacitance greater than theactual C0 value due to theinfluence of sub-resonance willresult (Figure 5). In this case,measurements mode at afrequency sufficiently separatedfrom the resonant frequency areeffective an effective method forseparating C0 from the dataobtained in this way. In additionto the general 4-elementequivalent circuit analysiscommand, the HP E5100A alsohas commands to analyzes the6-element equivalent circuit and toanalyze the C0 value withsub-resonance and its effecteliminated. This ensures stricter,high speed equivalent circuitconstant analysis.

High speed resonant pointsearch by SRCHFR? command(Option 023)

Without using the frequencysweep, the SRCHFR? commandautomatically moves the E5100Asignal source to the 0 phase

point, thereby finding the Fr andCI values. This function finds theFr and CI values at a much higherspeed than normal frequencysweep measurement. TheSRCHFR? command is

particularly effective for deviceshaving high Q-values. Sweepingover an extensive range will berequired if accurate resonantfrequency is not clear. When themeasurement range is the same,measurement with the SRCHFR?command is much more rapidthan by frequency sweep. Forexample, measurement requiringabout 350 sec. by frequency sweepmethod can be completed only in3.12 sec. by the SRCHFR?command. Since measurement ismade directly at the phase of 0,this method provides higherfrequency accuracy thaninterpolation with frequencysweep.

9

|Z|

Frequency

Fundamental Spurious

Figure 11. Comparison of the CI value and spurious signal resistance

Figure 12. 4- and 6-element equivalent circuit models

R1C1 L1

C0

G0

R0

R1C1L1

C0

Resonator

Electrode


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(2) High accuracymeasurement when usingPi-network test fixture

The Pi-network test fixture shownin Figure 13. is currently used as ameasurement fixture for highfrequency crystal resonators than1 MHz. The E5100A providesmany functions to facilitate theuse of the Pi-network test fixture.

Direct power setting whenusing Pi-network test fixture

The network analyzer output power has been represented in

terms of dBm. In addition to this,the E5100A permits setting interms of watts and amperes, withconsideration given to dampingwhen using the Pi-network testfixture. Accordingly, the drivelevel applied to the device can beset directly from the front panel.

3-term calibration function of Pi-network test fixture

When using the Pi-network testfixture for measurement,THRU-calibration alone will makeit more difficult to remove theimpact of residual impedance andstray admittance around thefixture with increasing frequency(mainly in the range of 10 MHz ormore) and will result in increasedmeasurement errors. This problemcan be solved by the 3-termcalibration function (pi-calibrationfunction) of the HP E5100A.

Figure 13. Pi-network test fixture

Basic pi-calibration principles

As shown in Figure 14, thePi-network test fixture in S21measurement contains four errorcomponents. Assuming the deviceequivalent circuit as shown in Figure15; then these error components canbe replaced by three variables. Toeliminate these three errorcomponents, three standards(OPEN/SHORT/LOAD) are used toperform 3-term calibration

(pi-calibration), as shown in Figure16. This pi-calibration allows allthree error components to beremoved and enables the Pi-network test fixture to make highly accuratemeasurements at high frequenciesthat would be difficult if onlyconventional through-calibrationwere used.

10

X'tal

66.2 66.2

159 14.2 14.2 159

50 5012.5 12.5

EXFS 21M

ETF

ELFESF S 11AS 21A

S 22A

S 12A

Device Under Test

ETFS 21A(1 - E SF S 11A) (1 - E LFS 22A) - E LFESF S 21AS 12AS

21M = E XF +

Figure 14. Pi-networktest fixture errormodel


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(3) Automatic measurementand effective data processing

HP Instrument BASIC(I-BASIC) programmingfunctionThe system has a built-inHP I-BASIC programming functionand provides automaticmeasurement and GO/NO-GOselection as a single the networkanalyzer. In addition to control of measuring functions from anexternal PC, the HP E5100Asupports a program subsystemcommand that allowsmeasurement and analysis data

processing in the PC-controlledautomatic measurement systemand optimization of themeasurement sequence. When thisfunction is utilized, analysis dataand calculation results obtainedfrom the I-BASIC program can betransmitted to the external PC.This function also allows changesin the I-BASIC arrays from theexternal PC, and permits transferof the I-BASIC program itself

between the external PC andHP E5100A.

Figure 17 illustrates the use of the program subsystem command tothe variables gained in theI-BASIC program from an externalPC. This function serves to ensurethat measurement, analysis anddata analysis processing areexecuted by the I-BASIC program,and that only the final result issent to the external PC.

This allows the external PC processing load to be reduced,and enables all measurement-related files to be managed on the

PC. Furthermore, the EXECUTEcommand is dedicated to theI-BASIC program, thus providingquicker handshaking than theHP-IB command, and ensuringhigh speed data analysis.

11

S 21M = EXF +1 + E MS 21A

ETS 21 A

OPEN

SHOR

LOAD

Total = 55

10 ASSIGN @E5100 TO 71720 OUTPUT @E5100; "PROG:NUMB? A"30 ENTER @E5100; Total40 DISP "Total= "; Total50 END

10 A=020 FOR I=1 TO 1030 A=A+I

40 NEXT I50 PAUSE

External PC Program E5100A I-BASIC Program

Figure 17. An example of data transmission using the program subsystem command

Figure 15. Basic formula for deviceequivalent circuit and 3-termcalibration

Figure 16. Three standards forpi-calibration


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3.5-inch FDD and built-in RAM diskThe DOS format 3.5-inch floppydisk drive incorporated in the

system ensures easy programmanagement and statistical

processing of the measurementdata by the PC.

24 bit/8 bit parallel I/O interfaceUse of the parallel I/O interfaceallows high speed handshakingwith the automatic equipment.This function ensures effectivesystem design for automaticmeasurement accompanying theGO/NO-GO selection. This

function can also be used fortrigger input from an externalswitch, including a foot switch inthe manual measurement mode.

Conclusion

The many functions of theHP E5100A support an effectivecrystal resonator production lineand from pre-process to

post-process, provide an effectivemeans of evaluation throughoutan automatic inspection line.

For more information on Hewlett-PackardTest and Measurement products,applications, or services please call yourlocal Hewlett-Packard sales office. Acurrent listing is available via the Web

through AccessHP at http://www.hp.com. If you do not have access to the internet, please contact one of the HP centers listed below and they will direct you to yournearest HP representative.

United States:Hewlett-Packard CompanyTest and Measurement Organization5301 Stevens Creek Blvd.Bldg. 51L-SCSanta Clara, CA 95052-80591 800 452 4844

Canada:Hewlett-Packard Canada Ltd.5150 Spectrum Way

Mississauga, OntarioL4W 5G1(905) 206 4725

Europe:Hewlett-PackardEuropean Marketing CentreP.O. Box 9991180 AZ AmstelveenThe Netherlands

Japan:Hewlett-Packard Japan Ltd.Measurement Assistance Center9-1, Takakura-cho, Hachioji-shi,Tokyo 192, JapanTel: (81) 426 48 3860

Fax: (81) 426 48 1073

Latin America:Hewlett-PackardLatin American Region Headquarters5200 Blue Lagoon Drive9th FloorMiami, Florida 33126U.S.A.(305) 267 4245/4220

Australia/New Zealand:Hewlett-Packard Australia Ltd.31-41 Joseph StreetBlackburn, Victoria 3130

Australia131 347 ext. 2902

Asia Pacific:Hewlett-Packard Asia Pacific Ltd17-21/F Shell Tower, Times Square,1 Matheson Street, Causeway Bay,Hong Kong(852) 2599 7070

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Copyright 1996Hewlett-Packard CompanyData subject to changePrinted in U.S.A. 8/965965-4972E

HP-PNE5100A-2_Crystal Resonator Measuring Functions Of HP E5100A-B Network Analyzer

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