ERT数据采集系统信号发生模块的设计

The design of the signal generator module of ERT data acquisition system

电阻层析成像系统(Electrical Resistance Tomography,简称ERT)具有无扰动、无辐射、可视化、可在线测量等特点,在两相流测量中有很广阔的应用前景。ERT数据采集系统信号发生器模块通常有模拟式和直接数字频率合成(Direct Digital Frequency synthesizer,简称DDS)式两种类型。其中,DDS具有较高的频率分辨率,可实现快速的频率切换,且在频率改变时能够保持相位的连续,很容易实现频率、相位和幅度的数控调制。本文用DDS芯片AD7008及外围电路组成了ERT数据采集系统信号发生模块,产生频率、幅值、相位可调的正弦波。

Electrical Resistance Tomography as an online measureme nt technique has the advantages of non-invasion, non-radiation and visualization, so it has a wide prospect in the two-phase flow measurement, Signal generator module of ERT data acquisition system usually has two styles： the simulation and Direct Digital Frequency synthesizer,（DDS）.DDS has a higher frequency and can switch the frequency quickly and can keep the phase continuous when the frequency changes, It can easily achieve the frequency , phase and amplitude numerical control. Signal generator module of ERT data acquisition system is made using the DDS chip AD7008 and its Peripheral Circuit and the sine wave which has adjustable frequency, phase and amplitude is generated.