【摘要】 本文提出一种利用FPGA和眼图实现在工程上测量数字信号传输性能的一种方案;重点介绍了其结构、算法原理及具体实现原理;以ALTER公司的EP1C6Q240C8N为核心实现数字信号的编译码,通过三个2阶巴特沃斯低通滤波器和一个伪随机信号发生器用来模拟传输信道,滤波器采用TI的OPA系列作为核心芯片,加法电路采用的是THS4001、整形电路采用的是LM331,利用FPGA产生时钟信号、M序列、伪随机序列和曼彻斯特码,同时它也用于曼彻斯特码同步时钟信号的提取和译码。在本系统中10MHZ的伪随机序列用来模拟实际环境中的噪声。通过该系统将原信号进行编码、传输以及解调得到解调信号。实现了一个简单的数字传输性能分析仪的设计与制作,最终测量正确的眼图,达到预期的效果。更多还原

【Abstract】 The article proposes an approach to implement the measurement of the digital signal transmission performance on the project by using FPGA and the eye pattern,which mainly introduces its structure,the algorithm and the detailed principle of the implementation.Encoding and decoding the digital signal is based on EP1C6Q240C8N of ALTER company.By using three 2-order Butterworth low-pass filters and a pseudo-random signal generator to simulate the transmission channel.The filters use TI’s OPA842 as the core chips.The addition circuit is THS4001.The shaping circuit uses LM331.The clock signal,M series,pseudo-random sequence and Manchester code are generated by FPGA,it’s also used to recover the synchronous clock signal from Manchester code and decode at the same time.The 10MHZ pseudo-random sequence simulates the actual environment noise in the system.The system can encode the original signal,transmit it and get the demodulated signal finally,which implements the design and production of a simple digital transmission performance analyzer and ultimately measure the correct eye pattern.更多还原