磁感应断层成像中的高频率稳定度信号源的选择

磁感应断层成像系统中信号源频率稳定度对相位测量精度有着重要的影响.推导了信号源频率稳定度与系统相位漂移的关系,且对采用DDS、PLL两种方式实现的信号源频率稳定度进行了测量和对比,测量了采用不同频率稳定度的信号源时系统的相位漂移.结果表明,DDS产生的信号频率稳定度较高,系统相位漂移随信号源频率稳定度的提高而减小.

Selection of High Frequency Stable Signal Source in Magnetic Induction Tomography

Frequency stability of signal sources has an important effect on phase measurement accuracy in a magnetic induction tomography system. This article derives the relation of signal source frequency stability to system phase drift, and measures and compares the frequency stability of signal sources by using DDS and PLL. The system phase shift is also measured by using different signal sources. Experiments show that the frequency stability of signals generated by DDS is upgraded, and the system phase shift is reduced with the upgraded signal source stability.