摘要
为了对线性时不变系统进行频率特性进行测试,本设计提出了一种低成本、面向学生的频率特性测试仪的设计方案,本仪器为基于FPGA及高速ADC/DAC构建的数字频率特性测试仪系统。其通过DDS产生正弦扫频信号,经高速DAC转换输出,被测网络响应信号由ADC采集后输入FPGA,得出信号经被测网络后产生的幅度变化和相位变化。本仪器具有0~20 MHz的扫频范围、±40 d B输入增益范围、5°相位分辨率、可实时显示被测网络的幅频特性曲线和相频特性曲线,并可将测试结果保存为文件。本设计成本低、易实现、具有较强的可扩展性,可很好地满足目标人群的要求。
To measure the frequency characteristic of the linear time-invariant system, we proposed a design of a low cost FCI for university students. This instrument is based on FPGA and high-speed ADC/ DAC system.It uses DDS to generate the sine wave sweep signal.Transformed by the DAC, it is output to the measured network. Then the response of the measured network is acquired by the ADC and sent to FPGA. The FPGA measures the changes of the amplitude and the phase of the signal and sends the results to PC to display. The instrument has a frequency range of 0-20 MHz, an input gain of ±40 dB, a phase resolution of 5°, and can display the amplitude-frequency curve and the phase-frequency curve in real-time. The results can be saved as flies. The design is low cost, easy to implement and strongly scalable, and can meet the needs of the target population well.
出处
《电子设计工程》
2017年第11期102-106,110,共6页
Electronic Design Engineering
