基于FPGA的同步信号发生器设计

发布时间：2018-02-25 23:37

本文关键词： 同步信号 FPGA 直接数字频率合成 UART　出处：《西安电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：FPGA(Field Programmable Gate Array)器件的应用是继单片机之后,当今嵌入式系统开发的关键技术之一,无论在高校还是企业都得到了广泛的应用。直接数字频率合成(DDS,Direct Digital Synthesizer)技术是从信号相位概念出发,以高速数字器件为基础,直接合成所需波形的一种全数字频率合成技术,相对于传统的模拟频率合成技术,具有成本低廉,性能稳定,功能集成度高以及产品体积小等一系列优点。本文以FPGA为硬件基础,结合DDS技术作为理论支撑,设计了一款同步信号发生器,其功能是产生两路频率可实时调整,且分辨率在0.001Hz以下的方波信号,分别作为视频信号的行同步信号和场同步信号,最终运用在视频还原项目中。本文的主要工作如下:1.对串行异步通信进行了研究。根据项目的实际需求,需要通过计算机来控制FPGA输出两路同步信号,考虑到串行通信具有成本低,易实现的特点,因此采用通用异步收发传输器(UART,Universal Asynchronous Receiver/Transmitter)作为计算机与FPGA的通信接口。本文主要对该通信方式的数据格式、波特率以及数据采样等特性进行了研究,并在FPGA上设计实现了这种通信方式。2.对DDS技术进行了研究。计算机将目标信号的频率值通过串口传输到FPGA内部后,以DDS的方式合成信号,因此本文对DDS的技术原理及实现方式进行了研究,并在FPGA内部搭建了以DDS为基础的模块。由于同步信号发生器最终产生的是方波信号,并不需要产生正弦波和三角波,本文对DDS的ROM模块进行了简化和修改,使其更加适合项目的需求。3.对所有模块进行综合实现和仿真。模块代码完成之后,需要用综合工具进行由代码转换为实际电路的工作。本文采用Xilinx公司自带的综合工具ISE对模块进行编译、综合和布局布线,之后将程序烧入FPGA内部,用示波器对波形进行观察。发现问题之后,通过不断对程序进行仿真与综合,以及对输出波形的直观观察查找问题,解决问题。4.完成最终电路板和上位机程序。波形正确之后,完成电路板的焊接工作,最后由于项目需求,即需要用计算机输入频率值,本文通过对串口调试程序源码进行更改,在计算机上实现上位机程序,可以顺利的与FPGA之间进行频率信息的传输。
[Abstract]:The application of FPGA(Field Programmable Gate Arraydevice is one of the key technologies in the development of embedded system after the single chip microcomputer, which is widely used in universities and enterprises. Direct Digital Frequency Synthesis (DDS) Digital Synthesis (DDS) technology is based on the concept of signal phase. Based on high-speed digital devices, an all-digital frequency synthesizer which directly synthesizes the required waveforms, compared with the traditional analog frequency synthesis technology, has the advantages of low cost and stable performance. Based on FPGA and DDS technology, a synchronous signal generator is designed, whose function is to generate two channels of frequency that can be adjusted in real time. A square wave signal with a resolution of less than 0.001Hz is used as a line synchronization signal and a field synchronization signal, respectively. The main work of this paper is as follows: 1. The serial asynchronous communication is studied. According to the actual requirements of the project, we need to control the FPGA to output two synchronous signals through the computer. Considering the low cost and easy realization of serial communication, UART Universal Asynchronous receiver / Transmitter is used as the communication interface between computer and FPGA. The characteristics of baud rate and data sampling are studied, and this communication mode is designed and implemented on FPGA. The DDS technology is studied. The frequency value of the target signal is transmitted to the FPGA through the serial port by computer. In this paper, the technical principle and implementation of DDS are studied, and a module based on DDS is built in FPGA. Because the synchronous signal generator produces square wave signal, There is no need to generate sine wave and triangle wave. This paper simplifies and modifies the ROM module of DDS to make it more suitable for the requirements of the project .3.All the modules are implemented and simulated synthetically. After the completion of the module code, It is necessary to use synthesis tool to convert code to actual circuit. In this paper, the module is compiled, synthesized and wired by ISE, which is a comprehensive tool of Xilinx Company, and then the program is burned into FPGA. Using oscilloscope to observe the waveform. After discovering the problem, we can solve the problem by constantly emulating and synthesizing the program, and by observing and finding the output waveform directly. Finally, the final circuit board and upper computer program are completed. After the waveform is correct, To complete the welding of the circuit board, because of the requirement of the project, that is, to input the frequency value with the computer, this paper changes the source code of the serial port debugging program, and realizes the upper computer program on the computer. The frequency information can be transmitted smoothly with FPGA.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM935

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