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1.
双膜片结构光纤光栅地震检波器低频特性的研究   总被引:4,自引:2,他引:2  
提出了一种双膜片式的光纤光栅(FBG)地震检波器,此结构有效限制了检波器横向响应。对该检波器的纵向加速度灵敏度和幅频特性进行了理论分析,并指出了影响这种检波器纵向加速度灵敏度的因素。实验结果表明,该种检波器在5~200Hz频率范围内频响平坦,纵向加速度灵敏度为24.3pm/g,谐振峰在900Hz附近,与理论计算较好的吻合。  相似文献   

2.
基于光纤Bragg光栅的地震检波器的理论与实验研究   总被引:4,自引:4,他引:0  
提出了一种新型的基于光纤Bragg光栅(FBG)的地震检波器。FBG地震检波器传感头由平面弹簧片、质量块和FBG构成。给出了该检波器的力学模型,理论推导与分析了该检波器的幅频特性和加速度灵敏特性,并讨论了影响该检波器灵敏度的主要因素。实验结果表明,该检波器具有良好的线性度、稳定性和耐受性;检波器的频率响应范围为10~140 Hz,传感器灵敏度为25.9pm/g,共振频率为167 Hz,较符合理论值;最高可检测加速度值大于30g。  相似文献   

3.
激光多普勒检波系统的研究   总被引:3,自引:3,他引:0       下载免费PDF全文
为了进一步提高地震检波器的指标,研究了激光多普勒测量方法和微弱信号检测技术等,设计出了一种LD做光源的差动式激光多普勒检波系统,此系统采用高斯光束聚焦、大口径透镜接收,能接收到很强的多普勒信号,并且具有高的空间分辨力,同时,采用声光调制技术及锁相放大技术,提高了信号的信噪比,其结构简单、紧凑,装调方便,光能利用率和空间分辨力高,可测频率范围为0.5Hz~1000Hz;振幅范围为2μm~5mm;频率测量精度为0.6%;振幅测量精度为1%。  相似文献   

4.
我们所用的各种音响、视频设备、家用电器及仪器、仪表等使用的交流电能。是由电厂发出,以50Hz的传输频率。经升压后长途跋涉最后降压成220V到达我们的使用场地。尽管教科书上、各种电器设备说明书及铭牌上的电参数中标明的工作频率都是“50Hz”,这是公认的定律。但我们影音器材的信号频率.远远都超过50Hz的频率。如音响器材的音频频率范围是20Hz~20kHz。所以,“50Hz”仅是源源不断的电能在供电网中的运载频率。  相似文献   

5.
《变频器世界》2006,(6):17-17
伦茨8200系列矢量变频器覆盖的功率范围为三相输入下0.55~90kW,具备极宽的电压及频率范围(320~550V,45~65Hz),能很好地兼容不同地域的供电标准并满足多种应用领域的需求。8200系列矢量变频器还提供了一个PID控制器,因此,无需任何外部控制即可实现节能运行。其典型应用主要包括泵类和用于空气调节的风机。  相似文献   

6.
采用DDS技术,以AD9851芯片为核心,LCD12864液晶为显示模块,采用矩阵键盘输入的函数信号发生器.该信号发生器能够产生正弦波和方波,实现正弦波输出频率范围100 Hz~10 MHz,方波输出频率为100 Hz~1 MHz,频率分辨率为0.04 Hz,在频率范围内实现步进调节和任意调节两种控制方式并可显示产生的波形的频率和步进单位等信息.该信号发生器具有频率稳定,变频快速,幅值稳定,波形失真度低,电路结构简单,体积小,功耗低,价格低廉等特点.  相似文献   

7.
迈克尔逊干涉型加速度地震检波器集成芯片   总被引:7,自引:3,他引:4  
提出了一种新型的迈克尔逊干涉型混合集成光学加速度地震检波器。以尺寸为38mm×6mm×2mm的X切Y传LiNbO3晶体为基底,详细分析并设计了迈克尔逊干涉芯片的双Y分支波导、相位调制器和偏振器。对成功制作的迈克尔逊干涉芯片进行了通光测试,并对检测器进行了测试。结果表明,检波器及芯片性能良好,振动与检波器输出信号吻合良好。该检波器系统的主要设计参数为:自然频率3549Hz,相位检测灵敏度ΔΦ/a为1.1×10-2rad/m/s2,工作频带0~1065Hz。  相似文献   

8.
刘超  周瑜  张健博  张乐意  王坤博  李勤 《电视技术》2021,45(10):120-124
针对基于3×3相位解调的光纤地震检波器展开研究.利用基于最小二乘法的椭圆拟合法和微分交叉相乘算法,实现基于3×3相位解调的光纤地震检波器的两路输出信号的归一化,减小光纤3×3耦合器的非对称性和激光器的功率波动对光纤地震检波器的影响,解调出光纤地震检波器的相位,实现振动信号的准确还原.实验采用对比法测试了基于3×3相位解调的光纤地震检波器的性能,其灵敏度为320 rad/g@100 Hz,在5~400 Hz频率范围内的波动约为0.7 dB.该研究能够很好地应用于石油、天然气等地质勘探、地震监测以及周界安防等领域.  相似文献   

9.
四、箱体的作用 品质优良的扬声器单元是 保证高保真重放的必要条件,但不是充分条件,即使有了性能优良的信号源和功率放大器也是这样。比如,要获得一个重播频率范围为35~20000Hz的放声装置,假设信号源和功率放大器都能轻易满足这个要求,那么即使你选择一个谐振频率f_0为28Hz,有效频率范围为28~4000Hz的低音扬声器和有效频率范围为2500~25000Hz的优质高音扬声器,把它们与放大器连接在一起。我们会发现,它们根本达不到我们的要求:一是频率范围达不  相似文献   

10.
设计了一种频率可调范围约830MHz全集成CMOS LC压控振荡器.该压控振荡器利用了一种改进的四位二进制加权的开关电容阵列扩大了其调谐范围;采用了可变尾电流源设计,使得振荡信号在整个频率范围内幅度变化不大.结果表明,该压控振荡器总调节范围1.12~1.95GHz,功耗为6.5~19.1mW,采用0.35μm CMOS RF工艺设计版图面积为360μm×830μm,工作于1.1GHz和1.9GHz时,1MHz频偏处的单边带相位噪声分别为-122dBc/ Hz、-120dBc/ Hz.  相似文献   

11.
DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.  相似文献   

12.
This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel's.  相似文献   

13.
Waveguide multilayer optical card (WMOC) is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling & processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic (VB) language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.  相似文献   

14.
It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.  相似文献   

15.
The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.  相似文献   

16.
Today, micro-system technology and the development of new MEMS (Micro-Electro-Mechanical Systems) are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.  相似文献   

17.
The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.  相似文献   

18.
From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.  相似文献   

19.
The effect of laser microbeam trapping the bioparticles has been appfied widely in the biology .However the micromechanism of the acting that realizes the laser-microbeam trapping bioparticles is still lacking. In this paper ,the act microchenism of the gradiant force of laser microbeam for the bioparticles is analysed by means of quantum theory ,The result accords with our experiment.  相似文献   

20.
We have fabricated the white organic light-emitting devices (WOLEDs) based on 4,4' -bis(2,2 -diphenyl vinyl)-1,1' - biphenyl (DPVBi) and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene (rubrene). The device structure is ITO/2T-NATA (20 nm)/NPBX (20 nm)/CBP: x%Ir(ppy)3:0.5% rubrene (8 nm)/NPBX (5 nm)/DPVBi (30 nm)/Alq(30 nm)/LiF(0.5 nm)/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris (2-phenylpyridine) iridium [Ir(ppy)3], acts as a yellow light-emitting layer, and N,N' -bis- (1-naphthyl)- N,N' -diphenyl -1, 1' -biphenyl-4,4' -diamine (NPBX) acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir (PPY)3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.  相似文献   

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