少模光纤通信频域均衡中的大尺度FFT设计

发布时间：2018-01-06 03:39

本文关键词：少模光纤通信频域均衡中的大尺度FFT设计　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着对光纤中各个自由度复用的深入研究,由于非线性效应的影响,提升单模光纤信道容量的研究已陷入瓶颈。采用少模光纤进行模分复用是高速光通信研究的新潮流,但多个模式信道的传输中,模式色散的存在对信道均衡提出了严格的要求,而模式群延时随着传输距离的增大导致对均衡器中大尺度FFT的电路资源利用率有较高的要求。FFT的设计也从传统的中小点数向大尺度发展,并且设计重点由传统的提升运算速度和精度转向对资源的优化利用。本文对DFT的原理以及减少运算量的二维FFT和基-r算法进行了详细研究。对比了基-2、基-4和基-22算法的基本原理和实现过程,并对几种不同基数算法的运算量和控制复杂性进行比较,选择将二维算法与基-22算法结合使用来实现16384点的快速傅里叶变换,同时,结合FFT的运算特点采用顺序结构与流水线结构相结合的电路结构在FPGA中设计了16384点的FFT处理器及其使用的短点数运算模块。根据FFT的数据运算特点设计了各级的蝶形模块和数据存储模块;优化复数乘法器结构,减少占用的逻辑资源;根据数据寻址特点,设计了RAM和ROM地址发生器;最后设计了状态发生器产生整个FFT运算器的各个控制信号。对设计的FFT处理器各模块进行了功能仿真,通过Modelsim和MATLAB的联合仿真,验证了处理器功能的正确性。在50MHz时钟下,在Altera开发板上对处理器进行了调试,系统正确性在板级得到验证,最后,对FFT处理器的性能进行分析,在资源使用上具有明显优势,满足少模光纤通信频域均衡系统的需求。
[Abstract]:With the in-depth study on the reuse of different degrees of freedom in the fiber, due to nonlinear effect, enhance the channel capacity of single-mode fiber has been caught in a bottleneck. The few mode fiber mode division multiplexing is a new trend of high speed optical communication, but the transmission of multiple channel mode, existing mode dispersion and put forward strict requirements for channel equalization, and the mode of group delay with the increase of transmission distance to rate design of.FFT high requirements of the development from the traditional medium to large scale utilization of resource points to the large scale circuit equalizer FFT, and design the focus from traditional lifting speed and precision to the optimal use of resources in detail. This paper studies the principle of DFT and reduce the amount of computation of the two-dimensional FFT based -r algorithm. And compared based on -2, the basic principle and implementation process based on -4 and -22 algorithm based on, and several The amount of calculation and control algorithm are compared with the complexity of the base, choose the combination of two-dimensional algorithm and -22 based algorithm to achieve fast Fourier transform, 16384 points at the same time, combined with the operational characteristics of FFT circuit structure by sequence structure and pipeline structure is used to design a short point arithmetic module of FFT processor and its use in 16384 FPGA. According to the data characteristics of FFT at all levels of the butterfly module and data storage module design; optimize the structure of complex multiplier, reduce the occupied logic resources; according to the data addressing characteristics, design RAM and ROM address generator; each control signal generator generates the final design of the state of the FFT operator on the FFT processor design. The various modules of the functional simulation, through co simulation of Modelsim and MATLAB, to verify the correctness of the processor function. Under 50MHz clock in Altera The debugger is debugged on the development board, and the correctness of the system is verified at the board level. Finally, the performance of the FFT processor is analyzed, which has obvious advantages in resource utilization, and meets the needs of the frequency domain equalization system of the small mode fiber communication.

【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.11

【相似文献】