【作者】 张洁；

【导师】 戴居丰；

【作者基本信息】 天津大学 ， 电磁场与微波技术， 2007， 硕士

【摘要】 随着信息时代的到来,传统的通过电缆传递信息的方式已不能满足需要。光纤损耗低、带宽宽、容量大、原材料丰富,从各方面讲都是替代传统电缆的最好选择,所以国内对光纤检测仪器的需求很大。目前,光纤检测仪,即光时域反射仪,主要依赖于进口,这非常不利于我国知识产权的自主化,所以亟需开发一种低成本、测量准确、适合工程应用的光时域反射仪。本论文首先介绍了光纤测量技术的现状并给出了光时域反射仪的基本光学原理和基本工作原理,在此基础上提出使用嵌入式系统是实现此功能的最好选择;接下来详细介绍了我所搭建的数字平台,从功能、开发难度和成本几方面综合考虑最终确立了以DSP为中心主控芯片,FLASH、SDRAM和CPLD为外围功能模块的总体方案;而后介绍如何根据BOXcar原理编写程序完成系统功能,最后给出系统调试方法,包括硬件调试和软件调试以及在实际应用中积累的一些经验。文章深入探讨了ADI公司的ADSP-BF531的功能和开发过程,同时提出一种在功能和速度上都能很好满足系统需要的一种算法:BOXcar算法,并给出算法框图。ADSP-BF531是ADI公司新一代16位高速DSP产品,这一新产品是专为通信和互联网应用而设计的通用DSP芯片,能处理广泛用于互联网的大量图像、声音、文本和数据流,适用于电信和各种互联网设备。BOXcar算法是基于硬件BOXcar提出的一种改良算法,克服了硬件实现时离散性大,设备复杂等缺点,它的核心概念是积累平均。经过实际验证,证明该系统能够根据国际标准完成对光纤的衰减和长度等指标的检测且测量准确迅速,可以达到国外先进水平。更多还原

【Abstract】 Nowadays, our country’s information industry is developing at a phenomenal rate, through the traditional media to transfer the information have failed to meet the increased needs. The optical fiber as a new carrier has many merits, such as the lower spoilage, broader band width, larger capacity and the enough material, so it is the best choice to replace the traditional carrier. At present, the main device to detect the optical fiber is Optical Time Domain Reflector. Because in the project it is essential, so the demand is very big in our country, but the majority of instruments rely on in import. So it is not advantageous to the independence of our country’s intellectual property rights. Therefore we must develop one kind of low cost, suitable project application OTDR.Firstly, this paper introduce the present situation of the optical fiber examination technology and the basic optics principle and basic principle of work, in this foundation, proposing the embedded system is the best choice to realize this function. The embedded system is a popular research area, it widely applies in the electron, the medical service, the aviation and the automobile industry. Nest I introduce the digital platform, on this basis, I raised the main chip is ADSP-BF531, and the peripheral chips are FLASH、SDRAM and CPLD. After that, I introduced how to program according to the BOXcar principle. Last, I introduced the methods of system debugging.Mainly, I emphasized the function of main chip ADSP-BF531 and the main algorithm: BOXcar algorithm. ADSP-BF531 is ADI corporation’s new generation of high speed DSP product, this new product is designed for the communication and internet applications, and it can process the massive images, the sound, the text and data stream. The BOXcar algorithm is a kind of improvement algorithm, which based on the BOXcar device, it overcome a lot of shortcoming of the device.The experiments prove that this system can test the attenuation and the length of the optical fiber accurately according to the international standard.更多还原