1、BRITISH STANDARDBS EN 60444-9:2007Measurement of quartz crystal unit parameters Part 9: Measurement of spurious resonances of piezoelectric crystal unitsThe European Standard EN 60444-9:2007 has the status of a British StandardICS 31.140g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44
2、g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 60444-9:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 May 2007 BSI 2007ISBN 978 0 580 5066
3、8 0National forewordThis British Standard was published by BSI. It is the UK implementation of EN 60444-9:2007. It is identical with IEC 60444-9:2007.The UK participation in its preparation was entrusted to Technical Committee EPL/49, Piezoelectric devices for frequency control and selection.A list
4、of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal o
5、bligations. Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARD EN 60444-9 NORME EUROPENNE EUROPISCHE NORM April 2007 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normun
6、g Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 60444-9:2007 E ICS 31.140 English version Measurement of quartz crystal unit parameters - Part 9: Measurement of spu
7、rious resonances of piezoelectric crystal units (IEC 60444-9:2007) Mesure des paramtres des rsonateurs quartz - Partie 9: Mesure des rsonances parasites des quartz pizolectriques (CEI 60444-9:2007) Messung von Schwingquarz-Parametern -Teil 9: Messung der Nebenresonanzen von Schwingquarzen (IEC 60444
8、-9:2007) This European Standard was approved by CENELEC on 2007-03-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliog
9、raphical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in two official versions (English and German). A version in any other language made by translation under the responsibility of a CE
10、NELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary
11、, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Foreword The text of document 49/764/FDIS, future edition 1 of IEC 60444-9, prepared by IEC TC 49, Piezoelectric
12、 and dielectric devices for frequency control and selection, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60444-9 on 2007-03-01. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical nati
13、onal standard or by endorsement (dop) 2007-12-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2010-03-01 _ Endorsement notice The text of the International Standard IEC 60444-9:2007 was approved by CENELEC as a European Standard without any modificat
14、ion. _ EN 60444-9:2007 2 MEASUREMENT OF QUARTZ CRYSTAL UNIT PARAMETERS Part 9: Measurement of spurious resonances of piezoelectric crystal units 1 Scope This part of IEC 60444 describes two methods for determining the spurious (unwanted) modes of piezoelectric crystal resonators. It extends the capa
15、bilities and improves the reproducibility and accuracy compared to previous methods. The previous methods described in IEC 60283 (1968) were based on the use of a measuring bridge, which applies to non-traceable components such as variable resistors and a hybrid transformer, which are no longer comm
16、ercially available. Method A (Full parameter determination) Full parameter determination allows the determination of the equivalent parameters of the spurious resonances and is based on the methods described in IEC 60444-5 using the same measurement equipment. It is the preferred method, which can b
17、e applied to the measurement of low and medium impedance spurious resonances up to several k. Method B (Resistance determination) Resistance determination should be used for the determination of high impedance spurious resonances as specified, for example for certain filter crystals. It uses the sam
18、e test equipment as method A in conjunction with a test fixture, which consists of commercially available microwave components such as a 180 hybrid coupler and a 10 dB attenuator, which are well-defined in a 50 environment. This method is an improvement to the “reference method” of the obsolete IEC
19、60283. 2 Overview Piezoelectric crystal units show multiple resonances, which can be electrically represented by a parallel connection of a number of series resonant circuits. The one-port equivalent circuit of the complete crystal unit is shown in Figure 1 (taken from IEC 60444-5). EN 60444-9:2007
20、3 G0C0C1C2C3L1L2L3R1R2R3IEC 324/07 Figure 1 General one-port equivalent circuit for multiple resonances The total admittance Ytotof the equivalent circuit for n resonance modes is therefore Ytot= G0+ jC0+iiY(1) with Yi= Gi+ jBi= 1iii1RjLjC+ +(i = 1,2,n) (2) Index i = 1 represents the main mode, whil
21、e i = 2 n represents the spurious resonance modes. The spurious modes are regarded as uncoupled modes. Coupled modes can also be found by the described test methods, however their strong amplitude dependence does not allow for the precise determination of their parameters. The attenuation ispura , o
22、f a spurious mode i, is defined as the logarithmic ratio (expressed in dB) of its resistance Ri, to the resistance R1of the main mode: i ispur 101Ra20logR=(3) Figure 2 shows a typical spectrum for the spurious resonances of an AT-cut quartz crystal unit as displayed on a spectrum analyzer using a -n
23、etwork according to IEC 60444-1. EN 60444-9:2007 4 0 10 20 30 40 50 60 70 80 Attenuation dB20 900 000 21 000 000 21 100 000 21 200 000 Frequency HzIEC 325/07 Figure 2 Spectrum of spurious responses NOTE The attenuation values measured on a network analyzer depend on the termination resistance of the
24、 test fixture used (e.g. 25 for a -network of IEC 60444-1). They are different from the spurious attenuation as computed from equation (3). NOTE The frequencies and attenuation values measured on a network analyzer are different if the crystal resonator is connected to a load capacitor. See also not
25、e under 3.2.1.2. 3 Measurement methods The following measurement parameters are necessary and should be given in the detail specification: frequency range of the spurious resonances FRspurto be evaluated; level of drive. Care must be taken in selecting a suitable measurement (sweep) time. 3.1 Method
26、 A (Full parameter determination) The measurement system consists of a -network or an s-parameter test fixture in accordance with IEC 60444-1 and IEC 604445 in conjunction with a network analyzer or an equivalent setup. The admittance of the crystal is measured within the specified frequency range F
27、Rspur. The spurious resonances are isolated with the method of successive removal of resonances. From the admittance data, the equivalent circuit parameters of the various resonance modes are computed using one of the evaluation procedures described in IEC 60444-5. 3.1.1 Measurement procedure The te
28、chnique is described in more detail in 11. The measurement sequence is as follows: a) measurement of the static capacitance C0as in IEC 60444-5; 1Figures in square brackets refer to the bibliography. EN 60444-9:2007 5 b) measurement of the main mode parameters (i = 1) as in IEC 60444-5, the resultin
29、g parameters are: series resonance frequency fs= f1= 12equivalent electrical parameters R1, C1, and L1, and quality factor Q = 11111111RCRLQ= (4) c) measurement of the complex admittance Yres(f) in the specified frequency range FRspurMeasurement parameters: Assuming Q2, Q3, Qn Q1(5) the minimum sett
30、ling time tsetfor each frequency is: tset= 11Q(6) For at least two data points within the resonance bandwidth, the minimum number of data points N is N = spur1FR2Q (7) The minimum sweep time tswpis then tswp= tset N (8) NOTE If necessary the frequency sweep range FRspurmust be divided into several s
31、ub-intervals. Resulting parameters: The array of complex admittance Yres(f), expressed, for example as arrays for magnitude |Yres(j)|, phase res(j) and frequency f(j) with j = 1,2, N and f(1) = f1, the frequency of the main mode. Search for spurious resonance peaks The search for spurious resonances
32、 requires several steps to distinguish the resonance peaks from noise peaks and from broadband responses. See flowchart in Figure 3 for reference. Identify local maxima of Re(Yres(j) for neighbouring data points (j 1, j, j +1) For the analysis the real part of the admittance is used. Re(Yres(j) = |Y
33、res(j)|cos(res(j) (9) For j = 2 N1 the admittance values are analysed as follows: If Re(Yres(j) Re(Yres(j1) and Re(Yres(j) Re(Yres(j+1) then fpeak =f(j) is a candidate for a spurious resonance peak. EN 60444-9:2007 6 Distinguish between real peaks and fake peaks Fake peaks due to noise, etc. can be
34、identified by assuming a realistic Q-value for the spurious resonances with respect to Q1as determined in step b). Upper limit Qmax: Qmax= kmaxQ1with kmax= 2 10 (recommended: kmax= 5) (10) The minimum 3 dB half-bandwidth BWminfor a spurious resonance peak is therefore BWmin= 1maxf2Q(11) For each can
35、didate for a spurious resonance peak, the data points next to |Yres(fpeak)| are inspected. If the amplitude at each side is less than according to Qmax: res peakres peak minY(f )2Y(f BW )(12) then this peak is still accepted as a candidate. Otherwise, the peak is considered as a fake. Lower limit Qm
36、in: Qmin= kminQ1with kmin= 0,1 0,5 (recommended: kmin= 0,2) (13) The maximum 3 dB half-bandwidth BWmaxfor a spurious resonance peak is therefore BWmax= 1minf2Q(14) For each candidate for a spurious resonance peak , the data points next to |Yres(fpeak)| are inspected. If the amplitude at each side is
37、 greater than according to Qmax: res peakres peak maxY(f )2Y(f BW )(15) then the selected peak is accepted as a true spurious resonance peak. Otherwise, the peak is considered as a fake. Resulting parameters: n1 spurious resonance frequencies imf (i = 2 n) NOTE If the spurious resonances are very cl
38、ose to strong modes, it is recommended that a 1 dB instead of a 3 dB bandwidth is used. In the above equations, the term 2 must then be replaced by the factor 1,122, and the values for BWmaxand BWminmust be changed accordingly. EN 60444-9:2007 7 Y(fpeak) 2Y(fpeak BWmin)START j = 2 Increment j by 1 Y
39、ESBWmin=NONOPeak is a resonance peakYESRe(Y(i) Re(Y(j1) AND Re(Y(i) Re(Y(j+1) f12 Qmax, BWmax= f12 QminY(fpeak) 2Y(fpeak BWmax)YESIEC 326/07 NOFigure 3 Flowchart for spurious resonance search d) zooming of the identified spurious resonances For each of the true spurious peaks fspur(i) identified in
40、step c) a new set of admittance data is taken by zooming the frequency intervals fspur(i) BWmaxwith at least Ni= 11 data points per sweep interval and a minimum sweep time tswpof min maxswpmin 110 Q Qtk(16) EN 60444-9:2007 8 Resulting parameters: Arrays of admittances for each spurious resonance ()i
41、rawYf, expressed by the arrays of amplitude ()iresYj, phase ()iresarg(Y j ) , and frequency fi(j) with i = 2 n and j = 1. 11 e) removal of the admittances of the main mode (i = 1) and of C0From each set of raw admittances ()irawYf the contribution of the main mode and of the static capacitance C0are
42、 subtracted. ()iresYf = ()irawYf Y1(f) Y0(f) (i = 2 n) (17) with Y1(f) = 1iii1RjLjC+ +(18) ()00CjfY = (19) 2f= (20) Resulting parameters: Arrays of admittances for each spurious resonance ()iresYf, expressed by the arrays of amplitude ()iresYj, phase ()iresarg(Y j ) , and frequency fi(j) with i = 2
43、n and j = 1. 11 f) Calculation of the series resonance frequency and the equivalent parameters of the strongest (remaining) mode The strongest (remaining) mode is selected. This is the kthmode, in which the maximum value of the real part given by ()()( )iresmax Re Y f is largest. Calculation for the
44、 series resonance frequency fks, the motional parameters Rk, Ck, and Lk, and the Q-factor Qkfrom Ykres(f) are given in IEC 60444-5. Resulting parameters: Series resonance frequency ksf , motional parameters Rk, Ck, Lk, and Qkof strongest (remaining) mode. NOTE If the settling time computed from k ks
45、etksQt2f=(21) is larger than swpitN(see equation (16), then the measurement of that spurious mode must be repeated with an accordingly corrected sweep time. g) Removal of the evaluated spurious resonance From all remaining sets of admittances ()iresYf the contribution of the kthspurious mode evaluat
46、ed in f) is subtracted. EN 60444-9:2007 9 ()iresYf:= ()iresYf Yk(f) (i = 2 n, i k) (22) with Yk(f) = 1kkk1RjLjC+ +(23) and Yires(f) is replaced by the result of the next iteration. h) Continue with step g) for all remaining spurious resonance i) Evaluation of the validity of the analysis (optional)
47、From the parameters of all determined spurious resonance modes and the main mode the total admittance Ytotcan be computed as ()=+=niiiifCjfCjfLjRfY101tot2212 (24) and compared with the admittance Yres(f) measured in step c). From the normalized sum of error squares a measure of the quality of data f
48、itting can be derived. NOTE As all resonances can influence each other, the sum of error squares can be minimized further by variation of the parameters C0, f(i), Ri, Ciand Liwith i = 1. n. 3.2 Method B (Resistance determination) The measurement system consists of the same equipment setup as describ
49、ed in IEC 60444-5, but uses a different test fixture, which consists of a 50 , 180 hybrid coupler, a 10 dB attenuator and a variable balancing capacitor. All parts are commercially available components. Figure 4 shows the electrical circuit diagram of the test fixture. XUT is the crystal under test, Cbalis a variable capacitor of 1 10 pF range. The 50
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