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浏览/检索结果: 共2条，第1-2条 帮助 限定条件 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 A new approach to realize UART (EI CONFERENCE) 会议论文 2011 International Conference on Electronic and Mechanical Engineering and Information Technology, EMEIT 2011, August 12, 2011 - August 14, 2011, Harbin, China Wang Y.; Song K. 收藏  |  浏览/下载：23/0  |  提交时间：2013/03/25 In order to connect DSP which has synchronous serial ports to the devices implementing asynchronous communications protocol  a method to implement UART communications based on programmable logic device is proposed in the paper. In the proposed method  the core function of UART is integrated in CPLD with VHDL. Firstly  UART data frame format and operational principle of UART were introduced after reviewing some methods to realize UART. The methods to implement UART transmitter  UART receiver and baudrate generator using VHDL were illustrated in detail. Then pre-simulation and synthesize of VHDL program were executed. Finally  the test with bit error rate was carried out on physical system. Experimental results indicate that 75 percent of the GLB are used by UART  and the bit error rate is less than 109. The experiment was implemented utilizing the RS-422 protocol and the baudrate is 62.5kb/s. The proposed method can satisfy the system requirements of high integration  stabilization  low bit error rate  strong anti-jamming and low cost. 2011 IEEE.   Study on the fabrication of blazed grating with sub-micrometer space on aluminum film (EI CONFERENCE) 会议论文 12th International Manufacturing Conference in China, IMCC2006, September 21, 2006 - September 23, 2006, Xi'an, China Lun S.; Hao D.; Qi X. 收藏  |  浏览/下载：12/0  |  提交时间：2013/03/25 The saw tooth grooves of blazed grating ruled by ruling engine are formed by diamond tool which presses on the aluminum film evaporated on the substrate of optical glass or metal. The real shape of ruled saw tooth groove is different from that of the ideal groove and the ruling process indicates that there are the zero order planes  similar to the flat tops  on the grating grooves. The results of Fourier analysis for the real ruled grating featuring the zero order plane structure shows that the flat top width is an important factor for grating efficiency. Additionally  bigger pressure value loaded on the diamond tool and bigger lateral pressure value on the aluminum film will be benefit to the improvement of grating diffraction efficiency. Based on the grating interferometer  the high precision positioning control system of ruling engine guarantees the accuracy of the grooves space. High density blazed grating whose space is 0.83p.m is manufactured and its' grooves spaces are very equidistant and uniform under the view field of AFM. And the infrared blazed grating  whose diffraction efficiency in the first order is up to 97 percent  is ruled successfully also.