The absolute calibration of hydrophones using the planar scanning technique in the frequency range 0 , 5 mhzto 15 mhz 用0 . 5mhz 15mhz频率的水平扫描技术对水下扩音器进行的绝对校准
The absolute calibration of hydrophones using the planar scanning technique in the frequency range 0 , 5 mhz to 15 mhz 采用频率范围为0 . 5mhz至15mhz的平面扫描技术对水听器的绝对校准
Specification for absolute calibration of hydrophones using the planar scanning technique in the frequency range 0 , 5 mhz to 15 mhz 在0 . 5mhz - 15mhz频率范围使用的平面扫描技术水珍器绝对校正规范
The absolute calibration of hydrophones using the planar scanning technique in the frequency range 0 , 5 mhz to 15 mhz iec 61101 : 1991 ; german version en 61101 : 1993 0 . 5mhz至15mhz频率范围平面扫描技术对水听器的绝对校
2 . the radiant characteristics of the sar images are evaluated , which includes relative calibrations and absolute calibrations of the sar images , corrections of the antenna patterns , and ratio transforms and contrast adjustments of the sar images 2 . sar定标与其图像辐射特性评价,包括图像的内定标和外定标,以及以天线方向图校正、比例变换和反差调整为内容的sar图像的辐射校正和增强。
On the basis of practically achieved low - frequency laser - vibration measuring - system , this thesis analyses the principle of laser - vibration measuring - system , the optical factors which have effect on contrast degree of interference fringe , the optical - electric transformation factors which have effect on measuring accuracy , the important of filter for improving the accuracy in the absolute calibration and the outward vibration which has effect on system accuracy , etc . in chapter one , the background of laser measuring vibration , and then followed by its current status , is introduced and analyzed 本论文根据实际研制的激光测振仪系统,从提高激光测振仪精度的角度出发介绍了激光测振仪的原理,并详细地剖析了光路对测振仪干涉条纹对比度的影响、光电转换对测量精度的影响、光电信号的滤波放大以及外界振动对测振仪系统的影响等技术问题。
A new method of absolute calibration of photodetector sensitivity based on spontaneous parametric down - conversion ( spdc ) biphoton field is described . the process of spdc is studied theoretically . the single photon detection probability and two - photon coincidence probability are derived and the calibration principle for photodetectors is explained . an experimental system has been set up . the sensitivity of a photon - counting photomultiplier tube was measured , and the results were compared with those obtained using conventional method 讨论了一种基于自发参量下转换双光子场绝对校准光电探测器灵敏度的新方法,着重推导了对自发参量下转换过程中产生的单光子的探测概率和双光子的符合速率,从而阐明了绝对测量光电探测器量子效率的原理.基于这一方法对光子计数型光电倍增管的响应灵敏度进行了测量,并将实验结果与常规方法测得的结果进行了比较