毕业论文___dds信号产生与采集处理系统.doc

DDS信号产生 与数据采集处理系统 侏罗纪工作室 2007.3.30 摘要 本系统设计了一个基于FPGA的DDS信号源与数据采集处理系统。该系统包括DDS信号产生与数据采集处理两大模块。DDS信号源模块不仅能产生各种基本波形，可以进行信号的调频与调幅及输出两路相同频率，相位差精密可调的双路信号，还可以以线性和对数扫频的模式输出信号。数据采集处理模块通过两片高速A/D采集两路模拟信号，并输入到FPGA进行信号的变换与处理，处理单元可完成对信号参数的测量，调制与解调，及FFT频谱分析，抽取和插值及各种数字滤波变换处理。整个系统的参数预置采用矩阵式键盘输入完成，波形及其各种参数通过LCD显示。由于两大模块均采用基于FPGA的数字技术实现，使得该系统具有抗干扰性强，可靠性好，精密度高等优点。 关键词：FPGA DDS 调频 调幅 调相 扫频 FFT 滤波 Abstract The system deal with designing of DDS signal producing and data gathering and processing based on FPGA. There are two modules in this system including DDS signal producing and data gathering and processing. The module of DDS signal processing not only can generate kinds of basic waves but also can modulate frequency and modulate amplitude for the signals. Moreover it can output two signals whose frequency are the same and the phase difference can be modulate exactly in two channels, and it can output signals by the pattern of linear and logarithm sweep. The module of data gathering and processing gather two analog signal through two chip of AD and the signals that can be changed and processed are inputed to FPGA. And the cell of processing can measure the parameter of the signals , modulate and demodulate the signals also can analyse the frequency spectrum of FFT. Besides it has the fuction of interpolation and transform processing of kinds of digital filter. The parameter of the sysem is setted through matrix keyboard. The wave and the parameter are showed on the LCD. Because of the two modules are base on the digital technology of FPGA, there are many advantages of the system such as the strong anti-jamming, good reliability, high presision. Key words: FPGA DDS frequency modulation amplitude modulation phase modulation swept FFT filter 一 dds信号源 1总体设计 1.1引言 直接数字频率合成（DDS） 采用数字移相技术实现信号的移相 1.3.3 滤波方案 方案一：选用R、L和C以及运算放大器LM324等器件构成简单的二阶低通滤波器，根据实际需要选择电路参数，决定电路的形