Browsing by Author "Zelenka, Jiří"
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- ItemFrequency Temperature Characteristics Of The X-Length Strip Resonators Of At-Cut Quartz(I E E E, 1993) Zelenka, Jiří; Lee, Peter C. Y.The equations of motion of the coupled thickness-shear, thickness-length flexure, width-shear and width-length flexure deduced by neglecting of the piezoelectric coupling deduced from a system of one-dimensional equations of motion for AT-cut quartz strip resonators (by Lee and Wang, 1992) is employed for the study of the frequency temperature characteristics of the x-length AT-cut quartz strip resonators. The computed dispersion curves, frequency spectrum and the thickness-shear resonance frequency-temperature curves (the last two as a function of dimensions ratios) are given.
- ItemInfluence of electrode mass-loading on the electrical equivalent circuit of the trapped-energy at-cut quartz resonators(IEE, Stevenage, United Kingdom, 1996) Zelenka, JiříThe static Co and motional Cn capacitance of the electrical equivalent circuit of the AT- and BT-cut quartz resonators are computed. Another one comparison is done for infinitely large planparallel plate, for planparallel energy trapped resonator by considering the mass loading of electrodes and for the energy trapped resonator by considering the mass loading of electrodes and the spherically contoured surface of the plate. The calculated values are compared also with the measured one.
- ItemThe influence of electrodes on the frequency-temperature characteristics of rotated Y-cut quartz resonators(Elsevier Science Bv, 1997) Zelenka, JiříThe incremental two-dimensional equation of motion for small amplitude waves superposed on the omogeneous thermal strain are used for the theoretical description of the influence of the elastic stiffnesses and inertia of electrodes on the frequency-temperature characteristics of the fundamental thickness-shear vibration of the rotated Y-cut quartz resonators. The resonators are considered in the shape of the strip bounded in the X axis direction of the quartz crystal and fully covered on the faces perpendicular to the thickness direction by conducting electrodes. The piezoelectric properties of a quartz plate are neglected. The theoretically obtained results are compared with the measured frequency-temperature characteristics of the AT- and BT-cut quartz plates. 0 1997 Elsevier Science B.V.
- ItemThe influence of the dimensions of electrodes on the frequency-temperature characteristics of at and BT-cut quartz resonators(1996) Zelenka, JiříThe comparison of the measured resonant frequency-temperature characteristics of the AT- and BT-cut square and circular quartz resonators with the computed ones is given in the paper. The curves which express the frequency-temperature behaviour of the resonators are compared. The influence of the thickness of the silver and gold electrodes on the first order frequency temperature coefficient is presented. The influence of the dimension ratio of the wafer on the orientation for which the zero first order temperature coefficient occures at the temperature To = 25°C are given.
- ItemThe Influence Of The Electric Stiffening On The Resonant-Frequency Temperature-Dependence Of Quartz Resonators(Gordon Breach Sci Publ Ltd, 1992) Zelenka, JiříHolland, Sinha and Tiersten, Lee and Yong proposed a new method for the more precise determination of the temperature dependence of the resonant frequency of quartz resonators in the period from 1976 to 1984. The method is based on the proposition that the small vibrations of the quartz plate are superposed on the large thermally induced deformation. The extension of the Lee and Yong's method is explained in the paper. The piezoelectric properties and the temperature dependence of the piezoelectric constants and permitivities are considered by the description of the modified method.
- ItemKompaktní elektrické filtry s objemovými a povrchovými vlnami(Technická univerzita v Liberci, 1988) Zelenka, Jiří; Slavík, Milan; Košek, Miloslav; Stach, Vladimír; Katedra elektrotechnikyZpráva shrnuje výsledky řešeni dílčího státního úkolu základního výzkumu III-7-6/05 za léta 1987 a 1988. Je popsána řešená problematika, uvedeny dosažené výsledky a navržen další postup řešeni v oblasti metodiky návrhu filtrů a rezo-nátorů PAV, návrhu miniaturních páskových piezoelektrických rezonátorů a návrhu koaxiálního přepínače pro hromadné měřeni rezonátorů a oscilátorů. Zpráva je doplněna přehledem vynaložených nákladů a seznamem vzniklých zpráv a publikaci.