QQ客服 官方微博 反馈留言

浏览/检索结果: 共4条，第1-4条 帮助 限定条件 发表日期：2009    内容类型：会议论文    专题：长春光学精密机械与物理研究所    第一署名单位    第一作者单位    通讯作者单位     已选(0)清除 条数/页：5101520253035404550556065707580859095100   排序方式：请选择作者升序作者降序题名升序题名降序发表日期升序发表日期降序提交时间升序提交时间降序 Transceiving protocol designc for a free space optical communication system (EI CONFERENCE) 会议论文 2008 International Conference on Optical Instruments and Technology: Optical Systems and Optoelectronic Instruments, November 16, 2008 - November 19, 2008, Beijing, China Hualong W.; Wanxin S.; Zhongbao X. 收藏  |  浏览/下载：43/0  |  提交时间：2013/03/25 A new transceiving protocol is demonstrated for a Free Space Optical (FSO) communication system  and it's discussed in two parts: the transmitting protocol and the receiving protocol. During the discussion of these two parts  the cooperation of them is also discussed. Different from wired communication  an FSO system modulates the data on a narrow beam of laser transmitting through the free space or the atmosphere  and the protocol presented in this paper is mainly optimized for terrestrial Free Space Optical links  in which the signal channel of the system is mainly the atmosphere. Due to the complex composition and activity of the atmosphere  this signal channel brings in great influence on the transmitting laser in it  for example  the absorption and scattering of the atmosphere molecules and aerosols  the scintillation of received laser power caused by the turbulence of the atmosphere  all of which results in a much higher Bit Error Rate (BER) of the communication system. Thus in designing a protocol for an FSO system  more effort should be taken in the encoding of the data stream  the synchronization of the data stream  error checking and exception handling. The main function of the transmitting protocol includes interfacing the outer input data with a parallel port  buffering the input data  encoding the input data stream  serializing the parallel data and output the serialized data. It also has an output management unit to manage the activity of each part of the transmitting protocol. The main function of the receiving protocol includes filtering and synchronizing the input serial data stream  paralleling the serial data stream  decoding the input data  error checking  exception handling and interfacing the outer receiver with a parallel port. The entire transceiving protocol could be programmed into a single FPGA chip to improve system integrity and reduce the system cost. The presented protocol could be taken as "protocol transparent" for outer interfaces  meaning that when interfacing the presented system to an outer system  you don't have to consider what protocol the outer system transceiving data stream is under  for example  the TCP/IP protocol or anything else  in the case that its I/O interface is a parallel port. Simulation and final experiment prove that the protocol presented is working fine at a certain bit rate scale. 2009 SPIE.   Application of multi-sensors parallel fusion system in photoelectric tracing (EI CONFERENCE) 会议论文 2008 International Conference on Optical Instruments and Technology: Optoelectronic Measurement Technology and Applications, November 16, 2008 - November 19, 2008, Beijing, China Cheng G.-Y.; Cai S.; Gao H.-B.; Zhang S.-M.; Qiao Y.-F. 收藏  |  浏览/下载：15/0  |  提交时间：2013/03/25 To solve the real-time and reliability problem of tracking servo-control system in optoelectronic theodolite  a multisensors parallel processing system was proposed. Misdistances of three different wavebands were imported into system  and then prediction was done in DSP1 to get the actual position information. Data fusion was accomplished in PPGA imported by multi channel buffer serial port. The compound position information was used to control the theodolite. The results were compared with external guide data in DSP2 to implement correction of above calculation  and then were imported to epistemic machine through PXI interface. The simulation experiment of each calculation unit showed that this system could solve the real-time problem of feature level data fusion. The simulation result showed that the system can satisfy the real-time requirement with 1.25ms in theodolite with three imaging systems  while sampling frequency of photoelectric encoder was 800 Hz. 2009 SPIE.   System identification of tracking error and evaluation of tracking performance using BP neural network (EI CONFERENCE) 会议论文 International Symposium on Photoelectronic Detection and Imaging 2009: Advances in Infrared Imaging and Applications, June 17, 2009 - June 19, 2009, Beijing, China Zhang N.; Shen X.-H. 收藏  |  浏览/下载：14/0  |  提交时间：2013/03/25 A novel approach for evaluating the tracking performance of optoelectronic theodolite is proposed. First  an equivalent mathematic model of tracking error is established. Then  the equivalent sine signal is inputted to the equivalent model  and the outputs are sampled. The results of evaluating the tracking performance are obtained based on the statistical calculation of output produced by equivalent model. Equivalent model using the BP (Backprogration) neural network structure is identified. The training method of BP neural network adopts the LM (Levenberg-Marquardt) algorithm for the sake of speeding up training process. The BP neural network is trained and tested by using the training and testing samples gotten from the simulation model of optoelectronic theodolite tracking system under MATLAB/SIMULINK. The estimate errors of equivalent model including average error  maximum error and standard error are 2.5872e-0060  2.8 and 1.9. The results show that the equivalent model identified based on BP neural network meets the needs of evaluating the tracking performance of optoelectronic theodolite. The accurate evaluation of tracking performance is achieved. 2009 SPIE.   Design and tolerance analysis of compensator for high order aspheric surface testing (EI CONFERENCE) 会议论文 2009 International Conference on Optical Instruments and Technology - Optoelectronic Measurement Technology and Systems, October 19, 2009 - October 22, 2009, Shanghai, China Chen X.; Liu W.; Kang Y.; Wei Z. 收藏  |  浏览/下载：19/0  |  提交时间：2013/03/25 High accuracy is required in surface testing of 90nm nodal point lithography projecting lens. By comparing various aspheric surface testing methods  the structure layout of the compensator is a meniscus positive lens combined with a Plano-convex positive lens. The design results indicate that: primary and high order aberrations are balanced well  we adopt Offner null compensator to test the aspheric surface in the point diffraction interferometer at last. In this paper  MTF exceeds diffraction limit  an Offner compensator is presented on the base of the third order aberration theory to test concave aspheric surface  root-mean-square (RMS) of wave front error /167. The F-number of the system can achieve F/1.64. By the analysis of the process of aspheric surface testing with the designed system  the optical construction parameters of which is determined by introducing equal-quantities spherical aberration to compensate all orders of aspheric coefficients. The field of view of the system is 0.02  a loosen distribution of the tolerance was presented based on the accuracy of measuring apparatus. 2009 SPIE.