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钽酸锂晶体具有优异的压电性能,是声表面波(SAW)滤波器广泛使用的衬底材料。该文采用自主研制的提拉单晶炉,成功生长出4英寸、42°Y方向、外观完整的钽酸锂晶体。经可见及近红外分光光度计测试,晶体透过率接近80%;经X线摇摆测试,其半高全峰宽(FWHM)为28.4″,单晶性较好;采用差热分析仪对生长的晶体头尾进行居里温度测试,居里温度偏差为4.4 ℃。声表面波性能测试结果表明,钽酸锂晶体的声表面波速度、机电耦合系数和频率温度系数等指标均满足SAW滤波器的使用要求。 相似文献
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钽酸锂(LiTaO_3)是目前应用很广泛的压电、铁电和电光晶体。由于它的居里温度高(居里温度为618℃),因而制成器件可在高温下工作,不会退极化。另外它还有不溶于水、化学性能稳定等优点。现已广泛用来制作各种器件,如微声器件、机电换能器、红外探测器、激光调制器、超高频单片滤波器、与石英晶体合用作温度补偿晶体振荡器、作宽带晶体滤波器等等。无线传声器中应用LiTaO_3振子作调频振荡器的稳频控制器件,以使发射机具有良好的频率稳定性。70年代初我国研制出的无线传声 相似文献
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在目前获得高频钽酸锂晶体谐振器较难的情况下,该文以石英晶体为材料,通过化学腐蚀法,将谐振器的基波频率从45 MHz提高到63 MHz,并采用在传统差接桥型电路中插入LC调谐回路的电路展宽方式,将石英晶体滤波器的相对带宽从0.3%拓展到1%。基于该法研制出相对带宽约1%的63 MHz晶体滤波器,其带宽大于600 kHz,损耗为4 dB。 相似文献
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本文简要介绍钽酸锂晶体及器件的一些特性,对用该材料制作的21.4MHz宽带滤波器的设计、制作和测试结果作了较详细的介绍,滤波器的带宽达225kHz,矩形系数(BW_(?0dB)/BW_(3dB)为2.66,带外衰减在50dB以上。该材料在做宽带滤波器和压控振荡器方面具有优越性。 相似文献
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For the original article see ibid., vol.12, no.25, p203-3 (1976). C.C. Lin Provided an algorithm for designing symmetrical even-order all-pole bandpass polylithic crystal filters using dual-resonator monolithic crystal filter (MCF) elements. The commenter points out a couple of omissions in the algorithm given. With the corrections suggested, it was verified that the algorithm did provide a design procedure for all-pole filters that have any number of symmetrical MCF elements.<> 相似文献
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Integrated crystal filters-monolithic, tandem monolithic, and hybrid monolithic (polylithic) quartz crystal filters-are widely used in HF, VHF, UHF, and satellite communications equipments, in both commercial and military, in telephone FDM equipment, and in a number of other applications including frequency synthesizers and airborne navigation aids. Frequencies range from 5 to 180 MHz and occasionally to 250 MHz. Maximum inductorless bandwidths are usually 0.25 to 0.35 percent of center frequency below about 30-35 MHz and less at higher frequencies where overtones must be used. In the past decade, piezoelectric resonator theory has been extended to model accurately the linear and nonlinear behavior of monolithic filter devices. While most integrated crystal filters are all-pole networks, techniques for the design of filters with real and complex frequency transmission zeros are finding increasing application. A number of examples of current production filters are presented. 相似文献
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Experimental results validating a recently introduced exact theory for switched-capacitor lowpass ladder filters are presented. The prototype filter is a third-order Butterworth design using a low sampling/filter-cutoff ratio of 8.28 and has been fabricated in monolithic form. 相似文献
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介绍了以Li2B4O7为基片,150MHz声表面波窄带滤波器的设计与制作,在设计中采用了波导耦合谐振器的结构形式,按新研究的光刻腐蚀方法,成功地制作出了150MHz的窄带滤波器,验证了波导耦合谐振滤波的理论,证实了Li2B4O7确实是较怕表面波基片材料。 相似文献