基于DDS芯片的多频阻抗激励源的设计

Design of multi-frequency impedance exciting source based on DDS chip

目的:设计一个采用直接数字合成技术的电流模式多频阻抗激励源。方法:作者设计了基于DDS芯片AD9850的波形发生单元和基于AD844的电压电流转换单元的阻抗激励源系统。并对其各项性能进行了测试。结果:激励源的频率分辨率高,频率设置方便,VI电压电流转换性能较好,信号质量较高。结论:基于AD9850芯片的激励源适用于阻抗测量的实验系统和扫频模式的多频阻抗系统。

This paper is to design a current-mode multi-frequency impedance exciting source which adopts direct digital synthesis technology. The performances of the exciting source are tested, which is composed of the wave generation unit based on DDS chip AD9850 and the voltage-current conversion unit based on AD844. With high frequency resolution, convenient frequency setup, good performance of voltage-current conversion and high signal quality, the exciting source based on DDS chip can be applied to impedance measurement system in experiment and multi-frequency impedance system in frequency-sweep mode.