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	High-Accuracy Amplitude and Phase Measurements for Low-Level RF Systems 期刊论文 OAI收割 IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, 2012, 卷号: 61, 期号: 4, 页码: 912-921 作者: Wang, Z; Mao, LH; 刘熔; Liu, R 收藏 \| 浏览/下载：23/0 \| 提交时间：2016/04/08 Amplitude measurement discrete Fourier transform (DFT) digital IF high accuracy low-level RF (LLRF) oversampling phase measurement RF control
	Applications of digital if receivers and under-sampling technique in ladar 会议论文 OAI收割 international symposium on photoelectronic detection and imaging 2011: laser sensing and imaging; and biological and medical applications of photonics sensing and imaging, beijing, china, may 24, 2011 - may 26, 2013 SongZhi-Yuan; ZhuShao-Lan; DongLi-Jun; FengLi; HeHao-Dong 收藏 \| 浏览/下载：17/0 \| 提交时间：2012/07/09 Ladar Digital IF receiver Under-sampling Digital down-converter
	Earth elevation map production and high resolution sensing camera imaging analysis (EI CONFERENCE) 会议论文 OAI收割 Optoelectronic Imaging and Multimedia Technology, October 18, 2010 - October 20, 2010, Beijing, China 作者: Dai L. 收藏 \| 浏览/下载：141/0 \| 提交时间：2013/03/25 The Earth's digital elevation which impacts space camera imaging has prepared and imaging has analysed. Based on matching error that TDI CCD integral series request of the speed of image motion statistical experimental methods-Monte Carlo method is used to calculate the distribution histogram of Earth's elevation in image motion compensated model which includes satellite attitude changes orbital angular rate changes latitude longitude and the orbital inclination changes. And then elevation information of the earth's surface from SRTM is read. Earth elevation map which produced for aerospace electronic cameras is compressed and spliced. It can get elevation data from flash according to the shooting point of latitude and longitude. If elevation data between two data the ways of searching data uses linear interpolation. Linear interpolation can better meet the rugged mountains and hills changing requests. At last the deviant framework and camera controller are used to test the character of deviant angle errors TDI CCD camera simulation system with the material point corresponding to imaging point model is used to analyze the imaging's MTF and mutual correlation similarity measure simulation system use adding cumulation which TDI CCD imaging exceeded the corresponding pixel horizontal and vertical offset to simulate camera imaging when stability of satellite attitude changes. This process is practicality. It can effectively control the camera memory space and meet a very good precision TDI CCD camera in the request matches the speed of image motion and imaging. 2010 SPIE.
	Space camera imaging gain in-orbit adjusting strategy (EI CONFERENCE) 会议论文 OAI收割 2009 2nd International Conference on Intelligent Computing Technology and Automation, ICICTA 2009, October 10, 2009 - October 11, 2009, Changsha, Hunan, China 作者: Wang J.; He X. 收藏 \| 浏览/下载：17/0 \| 提交时间：2013/03/25 A Multi-Step Gain Adjusting Strategy (MSGAS) of space camera was proposed which was used to get higher SNR (Signal-Noise Rate) image. When the space camera working in poor light condition the CCD signal was so weak that it's difficult to get a clear image to reduce the quantization noise and improve the SNR we must amplify the CCD signal first and then quantize. The MSGAS was achieved by adjusting the gain of the CCD (Charge Couple Device) signal processor step by step the upper limit and lower limit were set if the MDN (Mean Digital Number) of a fixed length image data was not between the lower and upper limit the gain was adjusted step by step. In the experiment the upper limit lower limit and the step were set and the result of the experiment showed that MSGAS was robust and SNR was improved from 28 to 39. 2009 IEEE.
	The effect on tolerance distributing of an off-axis three mirror anastigmatic optical system with wavefront coding technology (EI CONFERENCE) 会议论文 OAI收割 Optical System Alignment and Tolerancing II, August 10, 2008 - August 11, 2008, San Diego, CA, United states 作者: Yan F.; Zhang X.-J.; Yan F. 收藏 \| 浏览/下载：35/0 \| 提交时间：2013/03/25 The wavefront coding technology is known as a system-level technology which can extend the depth of focus of optical system by innovative optical design and image restoration. This technology can control misfocus related aberrations including misfocus astigmatism and Petzval curvature temperature-related misfocus in digital imaging systems. It can also help optical system tolerate more residual error in optical manufacturing and alignment besides misfocus. The brief introduction of wavefront coding technology and the wavefront coded TMA system under research is presented respectively in part 1 and part 2. The "MTF similarity" is defined to describe the relationship among MTF at different position or different fields in the third part. It is also shown in this part that the MTF similarity of wavefront coded system is much higher than the normal system within a large range. In part 4 comparison between the origin system and the new system with wavefront coding technology is provided after multiple errors are introduced from which it can be observed that the system with wavefront coding technology can tolerate much bigger error than origin system. The error tolerance is re-distributed according to a new criterion based on MTF similarity. If the MTF similarity is less than a certain value it can be regarded that the system can tolerate the residual error. The new error tolerance is displayed and it is shown that the wavefront coding technology can also loosen the error distributing besides extended the depth of focus.
	AE signal processing and DSP implementation based on wavelet packet analysis (EI CONFERENCE) 会议论文 OAI收割 ICMIT 2005: Information Systems and Signal Processing, September 20, 2005 - September 23, 2005, Changchun, China 作者: Zhao J.; Wang K. 收藏 \| 浏览/下载：13/0 \| 提交时间：2013/03/25 To improve the accuracy of AE (Acoustic Emission) testing the wavelet packet analysis was introduced to process the AE signals. Extraction of the fault characteristic information would be influenced greatly if the faulted AE signal was not effectively denoised. Based on discussing the fast searching algorithm of BWPB (Best Wavelet Packet Basis) adopting Shannon entropy a new method based on BWPB was presented to denoise the AE signal from the faulted composite plate. Analyzing was performed on the denoised signal and the fault characteristic information was exacted. To improve the real-time performance of the wavelet packet analysis algorithm it was performed on the DSP (Digital Signal Processing) chip TMS320VC5409. The experimental results show that the algorithm can not only reduce the noise by 10dB but also effectively extract the faulted characteristics information from the AE signal.