摘要
采用现场可编程逻辑器件(FPGA),辅以必要的模拟电路,设计实现了一个基于直接数字式频率合成(DDS)技术的数字函数信号发生器。主要模块有键盘、波形表生成、频率控制、数模转换及幅度控制、显示控制和后级处理。其中键盘用来设定频率和幅度的大小以及波形的选择;FPGA用来改变DDS频率控制字,并由FPGA来实现波形表生成和频率控制,即DDS算法实现模块;将FPGA产生的波形数据送入到AD7520进行D/A转换。幅度控制由DAC0832内部的电阻分压网络实现;后级采用低通滤波器和OCL电路来提高输出波形质量并增强其带负载能力。
This article discuss how a FPGA acts as core, auxiliary by necessity analog circuit, and the digital function generator is designed ＆ constituted based on the DDS technology. The main module have the keyboard, the wave form generation, the frequency control, the digital-analog conversion and the amplitude control, the display control and latter level processing. Among them, the keyboard is used to set the frequency and amplitude, as well as the choice of waveform ; FPGA to change the word of DDS frequency control and to realize the waveform table＇ s generation; The profile data produces which FPGA sends in AD7520 to carry on the DA transformation. The amplitude control realizes by the DAC0832 internal resistance ladder network; The latter level uses the low pass filter and the OCL amplifier in order to improve the wave quality and strengthen its load characteristic.
出处
《东华理工大学学报（自然科学版）》
CAS
2009年第4期390-393,共4页
Journal of East China University of Technology(Natural Science)
基金
江西省高校教学改革研究立项课题(JXJG-06-10-17)
