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1、 INDD 512 85 D 2595512 0077797 072 D ADOPTION NOTICE ANSI/ElA-51, “Standard Methods for Measurement of the Equivalent Electrical Parameters of Ouartz Crystal Units, 1 kHz to 1 GHz,“ was adopted on 12 September 1994, for use by the Department of Defense (DoD). Proposed changes by Dd) activities nust
2、be subnitted to the DOD Adopting Activity: Laboratory, ATTN: AIISRL-EP-RD, Fort Momiouth, NJ 07703-5601. standard fran the Defense Printing Service Detachment Office, Building 4 D (Custaner Service), 700 Robbins Avenue, Philadelphia, PA 19111-5094. AL1 private sector and other Govermient agencies ma
3、y purchase copies frm the Electronic Industries Association, 2001 Eye Street, N.U., Washington, D.C. 20006. U.S. Army Research DOO activities may obtain copies of this Custodians: Army - ER Navy - EC A i r Force - 85 NASA - NA Review Activities: Ariay - AR, MI, SH Navy - AS, CG, MC, OS, SH A i r For
4、ca - 17, 19, 99 AMSC N/A 1 of 1 DISTRIBUTION STATEMENT A. Approved for piblic release; d i s t r i h t i o n i s unlimited. Adopting Activity: Army - ER Agent: DLA - ES (Project 5955-0634) FSC 5955 7 h i r ; L f EIA 512 85 3234600 O072832 9 f STANOARO ANSI/ETA- 512- 1985 APPROVED APRIL 10, 1985 EIA
5、STANDARD S T A N D A R D MEi“0DS FOR MEXUREME“ OF THE EQUIVALE“ ELECTRICAL PARAMETERS OF QUARTZ CRYSTAL UNITS, i k z to i m z 1 UA-512 I APRIL 1985 Engineering Department ELECTRONIC INDUSTRIES ASSOCIATION E I A 512 85 m 323Lib00 0072833 O m c . . NOTICE EIA Engineering Standards and Publications are
6、 designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existe
7、nce of such Standards and Pub- lications shall not in any respect preclude any member or non-member of EIA from manufacturing or selling products not conforming to such Standards and Publications, nor shall the e.xistence of such Standards and Publications preclude their voluntary use by those other
8、 than EIA members, whether the standard is to be used either domestically or internationally. Recommended Standards and Publications are adopted by EIA without regard to whether or not their adoption may involve patents on articles, materials, or processes. By such action, EIA does not assume any li
9、ability to any patent owner, nor does it assume any obligation whatever to parties adopting the Recom- mended Standard or Publication. This EIA Recommended Standard is considered to have international standardization implications, but the IEC activity has not progressed to the point where a valid co
10、mparison between the EIA Recommended Standard and the IEC Recommendations can be made. e Published ,by ELECTRONIC INDUSTRIES ASSOCIATION Ehgineering Department 2001 Eye Street, N.W. Washington, D.C. 20006 Copyright 198 5 Ail rights reserved ELECTRONIC INDUSTRIES ASSOCIATION PRICE: $15.00 Printed in
11、U.S.A. 4 EIA 512 85 M 3234b00 0072834 2 1 . -*% O EIA- 512 TABLE OF (XNIEC SCOPE 1 IMRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . 1 SECTION I THE PIEZOELECTRIC CRYSTAL UNIT AMI ITS ELECIRICALLY EQUIVllL,NNETWORK . . . . . . . . . . . . . . . . . . . . 2 SECTION II TWO-PORT CRYSTAL,
12、UNIT MEASUREMENTS AT LOWER FREQUENCIES. . . 5 SECTION III SINGLE-PORT REFLECTOMETERMEASURFMEWT. . . . . . . . . . . . , 7 A - Calibration . . . . . . . . . . . . . . . . . . . . . . . 8 B - Corrected Measurements . . . . . . : . . . . . . . . . . . 9 SECTION IV TWO-PORT S-PARAMETER MEiASlJIEhENTS .
13、. . . . . . . . . . . . . 10 A - System Calibration . . . . . . . . . . . . . . . . . . . 11 B - Corrected Measurements . . . . . . . . . . . . . . . . . . 13 SECTION V DATA REWCTION METHOD. . . . . . . . . . . . . ., . . . . . . . 16 A - Calculation of Parameters. . . . . . . . . . . . . . . 16 B -
14、 Verification of Data Integrity . . . . . . . . . . . . . . 17 SECTION VI MEASUREMENTSYSTEl6 . . . . . . . . . . . . . . . . . . . . 18 A - Instmentation. . . . . . . . . . . . . . . . . . . . . 18 B - Test Fixtures. . . , :. . . . . . . . . . . . . . . . . . 18 REFERENCES . . . . . . . . . . . :. .
15、 . . . . . . . . . . . . 20 TABLES TABLE I - SYMBOLS USED FOR DESCRIBING THE EQUIVALE“ ELECTRICAL “WORK OF A PIEZOELECTRIC CRYSTAL UNIT. . . . . . . 21 TABLE 2 - APPROXIMATE RELATIONSHIPS OF CHARAmISTIC FREQUENCIES . . . . . . . . . . . . . . . . . . . 24 EIA 512 85 = 3234b00 0072835 4 ETA-512 TABLE
16、 OF CONTENTS (cont) APPENDIX1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 FIGURES FIGURE 1 - EQUIVALENT ELECTRICAL NETWORKS CCNMONLY USED TO REPRESENT A PIEZOELECTRIC CRYSTAL UNIT OVER A NARROW FREQUENCY RANGE NEAR AN ISOLATED KIDE OF VIBRATION . . 26 FIGURE 2 - LOCI OF THE ADMITTAN
17、CE AND IMPEDANCE FUNCTIONS OF A PIEZOELECTRIC CRYSTAL UNIT FOR FREQUENCIES NEAR AN ISOLATEDMODE OF VIBRATION. . . . . . . . . . . . . 27 FIGUrG 3 - IMPEDANCE l Z l , RESISTANCE Re, REACTANCE Xe, AND SERIES-ARM REACTANCE X1 OF A PIEZOELECTRIC CRYSTAL UNIT AS FUNCTIONS OF FREQUENCY NEAR AN ISOLATED MO
18、DE OFVIBRATION, . . . . . . . . . . . . . . . . . . . . 28 FIGURE 4 - TEST CIRCUIT CONFIGURATION FOR I E A S N T OF LOW- FREQUENCY CRYSTAL UNITS. . . . . . . . . . . . . . . . . 29 F I m 5 - EQUIVALENT TRANSMISSION NETWON( OF FIGURE 4 FOR ANALYSIS OF LOW FREQUENCY CRYSTAL UNIT MEACUREMEWS. . 30 FIGU
19、RE 6 - TEST CIRCUIT CONFIGURATION FOR SINGLE-PORT REFLECTION MEASREMENTS OF CRYSTAL UNITS AT FREQUENCIES HIGHER THANlOQkHz . . . . . . . . . . . . . . . . . . . . . 31 FIGURE 7 - FLOWGRAPH OF THE REFLECTION MEASUREMENT SYSTEM OF FIGURE 6, AND THE SYSTEM RESPONSE AS A FUNCTION OF TRUE DEVICE REFLECTI
20、ON COEFFICIENT AND SYSTEM “ERROR“ VECTORS. . . . . . . . . . . . . . . . . . . . 32 FIGURE 8 - TEST CIRCUIT CONFIGURATION FOR TWO-PORT S-PARAMETER w - s . . . . . . . . . . . . . . . . . . . . . 33 FIGURE 9 - S-PARAMETER M E A S l J R E i b E W SYSTEM FLOWGRAPHS IN FORWARD ANDREVERSE CONNECTIONS. .
21、. . . . . . . . . . . . . . 34 ii -_ E I A 512 85 m 3234b00 O072836 b m STANDARL) METHODS FOR M E A S U R E i b E W OF THE EQUIVALm ELECTRICAL PARAMETERS OF QUARTZ CRYSTAL UNITS, 1 kiiz to. GHz (From EIA Standards Proposal No. 1792, formulated under the cognizance of EIA P-5.4 Working Group on martz
22、 Crystals.) iii E I A 512 85 323VbOO 0072837 8 Jk e. 2 EIA-5 12 Page 1 STANDARD METHODS FOR MEASUREMENT OF THE EQUIVALENT ELECTRICAL PARAMETERS OF QUARTZ CRYSTAL UNITS, 1 kHz to 1 GHz SCOPE: Methods are described which permit determination of fhe values of the equivalent electrical parameters of pie
23、zoelectric quartz crystal units, utilizing automated measuring equipment. The methods described make use of standard coaxial terminations, standard calibrated mismatched terminations, coaxial air-lines, and short-circuit terminations for both calibration of the instrument/ test fHture error terms, a
24、nd for verification of instrument performance. These coaxial standards, designed for 50 ohm systems, are readily available, and can be standardized in terms of national standards of impedance over very wide frequency ranges. The measurement methods described are intended to provide standard referenc
25、e values of the electrical equivalent parameters. Manufacturers and users may employ any other methods of measurement de si red,“ however, when other methods are used, the values obtained shall be correlated to those obtained by the reference methods. This standard is concerned only with the equival
26、ent electrical network which approximates the admittance/ impedance characteristic of a crystal unit over a relatively narrow range of frequencies near an isolated mode of vibration, at a particular excitation level. Non-linear amplitude behavior, or the presence of interfering modes of vibration, n
27、ot only interfere with the actual measurement, also render the accepted equivalent network representation invalid. INTRODUCTION The uses of piezoelectric crystal units in frequency control, filter and timing applications require accurate determination of the value of their equivalent electrical para
28、meters. This document presents a reference method for but measurement of the parameters of crystal units, based upon the use of automated state-of-the-art instrumentation systems which have become available in recent times. Using these methods, the measured parameter values are referenced to coaxial
29、, traceable standards of impedance, and are essentially independent of the particular instruments used in the measurement. Two basic methods are described: one, utilizing a two-port transmission method, characterizes the crystal unit as a three-terminal network; the second, utilizing a single-port r
30、eflection method, characterizes the crystal unit as a two-terminal device. Both methods yield the same values for the motional-arm parameter (RI, L1, and Cl), but the static capacitance parameters are different as discussed below. Section I describes the equivalent electrical networks which characte
31、rize the crystal unit as a two-port and as a one-port device, and lists the parameters necessary to define the network behavior. O E I A 512 85 m 3234600 0072838 T m EIA-5 1 2 Page 2 Section 1% presents a description of the two-port transmission measurement method recommended for characterizing the
32、three-terminal equivalent network at frequencies below 100 kHz, where directional couplers are difficult to obtain. Section III presents a description of a single-port reflectometer method for determining the two-terminal equivalent network parameters from 100 kHz to 1 GHz. Section IV gives a descri
33、ption of the two-port s-parameter method for determining the two-port network parameters, recommended for frequencies from 100 kMz to 1 GHZ. Section V describes the calculations required to obtain the equivalent network parameters from the corrected values of transfer admittance obtained by any of t
34、he methods of Sections II, III, or IV. All of the techniques of instrument calibration, data correction, and data reduction require extensive calculations, and are based on the utilization of a large number of individual measurements, which would not be feasible without the use of automated, softwar
35、e controlled instrumentation and computerized data reduction. However, it is the availability of these tools which permits the improved accuracy and reproducibility of results, and) renders previously used manual measurement methods obsolete. Section VI outlines measurement system considerations wit
36、h respect to instrumentation and fixturing. H . THE PIEZOELECTRIC CRYSTAL UNIT AND ITS ELECTRICALLY EQUIVALENT NETWORK A crystal unit consists of a mechanically resonant piezoelectric vibrator (usually a plate, bar, or tuning fork) with electrodes attached to or supported near to the element to exci
37、te one of its resonant frequencies. The electrical behavior of the crystal unit, as evidenced by the electrical admittance (or impedance) observed from its terminals, over a narrow range of frequencies near a resonance, can be represented by an equivalent electrical network. When the resonant mode o
38、f interest is sufficiently isolated from other modes of motion, the parameters of the equivalent network may be considered to be independent of frequency, and the equivalency will be nearly exact over a frequency band of at least a few percent. (If the mode of interest is not essentially isolated, t
39、he methods of measurement presented may still be used to determine the impedances of the unit, but any attempts to relate the frequency dependence of its impedance to the electrically equivalent network of Figure 1 will be futile!) Figure 1A shows the three-terminal equivalent-circuit representation
40、 of a crystal unit which is valid over a few percent band centered at resonance for an isolated mode of vibration. There are six parameters shown: . - . - . : : : . , ., . - -“.: *: . i;:.; . . . .- EIA-5 12 Page 3 C13 = Static capacitance from pin 1 to enclosure C23 = Static capacitance from pin 2
41、to enclosure Co = Static capacitance from pin 1 to pin 2, including the capacitance between electrodes and between support structures R1 = Series resonant resistance L, = Motional inductance Cl = Motional capacitance If the crystal unit is considered to be a two-terminal element (enclosure connectio
42、n neglected), it has an electrical equivalent as shown in Figure 1B. The motional parameters (R1, L1, and Cl) are the same as above; however, the value of Co will include the series combination of Cl, and C, as well as some effects of the capacitance from enclosure to ground. The frequency dependenc
43、e of device impedance will only be modeled as well as the various components of the composite Co are known. Consequently, the two-terminal equivalent circuit is recommended for use only in those applications where operation at a single frequency near series resonance is anticipated. The static capac
44、itance values are quite easily measured by conventional means, as they are relatively independent of frequency and not related to the resonant properties of the vibrator. Co will be slightly influenced by the impedance of the measuring circuit, as the free and clamped values for piezoelectric materi
45、als are different, depending on the piezoelectric coupling coefficient; for quartz crystals, however, the effect is small, and a quite satisfactory value of Co can be obtained, for example, as the average of a value measured a few percent below resonance, and a second value measured a few percent ab
46、ove anti-resonance. The trans-admittance (admittance between pins 1 and 2) of the crystal unit is quite accurately modeled by that of the equivalent network in Figure lA, over a band of frequencies extending several percent above and below resonance. Fortunately, this bandwidth is adequate to descri
47、be the behavior of almost any circuit in which the device will be used. The admittance characteristic is shown in Figure 2A, which is the admittance-plane locus of the vector relationship . - + j OC, - . 1 1 I R1 1 y 1 2 = Ri2 + (wL1 - -)2 OC1 This circular locus in the Y-plane clearly maps into a c
48、orresponding circular locus in the Z-plane, as shown in Figure 2B. There are several characteristic values which are commonly used in describing crystal units, whose relationship becomes clear from examination of Figure 2. The “fundamental“ constants which depend only on the motional properties of t
49、he vibrator are the series resonant frequency, f, and the values of Rl, L1, and Cl, associated with the motional arm circuit. The other frequencies of interest are: E I A 512 85 36334laOO I072840 8 = EIA-512 Page 4 fm = frequency of minimum impedance fr = frequency of zero-phase, low impedance fa = frequency of zero-phase, high impedance fn = frequency of maximum impedance fp = parallel resonance frequency (lossless) Clearly, all of these frequencies depend to at least some degree upon the effective value of Co; since connection into any use-
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