基于FPGA的频率特性测试仪的设计

Design of Frequency Characteristic Testing Instrument Based on FPGA

该频率特性测试仪主要包括系统控制部分,双路同步DAC部分,被测网络部分,信号采集处理部分,显示部分和电源部分。全系统以FPGA为主体,正交扫频信号源采用双通道高速DA模块实现,可产生两路正交输出的信号,扫频范围及扫频步进值可设置。被测网络由一个RLC串联谐振电路构成。频率特性测试及显示部分使用正交解调原理,将经过被测网络的信号与两路正交信号相乘,经低通滤波后,由单片机ADC采集数据,经单片机处理后在示波器屏上画出幅频特性曲线和相频特性曲线。通过调试和完善完成了题目要求的基本部分和发挥部分,并有自己创新的部分。

The frequency characteristic testing instrument mainly comprises a system control part, a double channel synchronous DAC part, a test network part, a signal collecting and processing part, a display part and a power supply part. The system takes the FPGA as the main body, and the orthogonal frequency sweep signal source is realized by using the dual channel high speed DA module, which can produce the signals of two channels quadrature output, the sweep frequency range and the sweep frequen- cy step value can be set up. The network is composed of a RLC series resonant circuit. Frequency characteristic test and display part using quadrature demodulation principle, will be through the detected network signal and two orthogonal signals are multi- plied, after low-pass filtering, by MCU ADC data acquisition, SCM processing on the oscilloscope screen draw the amplitude frequency curve and phase frequency curve. Through the debugging and improvement of the basic part of the requirements of the completion of the requirements and play a part, and have their own innovation.