基于直接数字合成技术用于心内膜三维标测的激励源设计

背景：低频电场定位方式下的心内膜三维标测技术中,激励源的设计是探测导管位置的前提。目的：旨在设计一种结构简单、集成度高、专用于心内膜三维标测的激励源,并通过动物实验对激励源性能进行测试分析。方法：基于直接数字合成技术,采用模块化设计,以单片机STC89C52控制三块直接数字合成芯片AD9851为核心,生成三路频率分别为28,30,32kHz的1mA正弦恒流信号。施加三路信号于动物体,采集并处理右心房内的定位信号数据,对激励源性能进行评价和分析。结果与结论：动物实验结果表明,三路信号的电流值均可稳定于1mA,其频率误差分别为0.054%,0.097%及0.056%,同时标测导管采集数据正常,能够分离出3个方向的电压信号。激励源恒流特性好、频率误差小,可满足心内膜三维标测的使用要求。

Excitation source design for endocardial three-dimensional mapping based on direct digital synthesis

BACKGROUND：The excitation source＇s design is precondition of detecting the catheter＇s position in endocardial three-dimensional （3D） mapping by low-frequency electric field.OBJECTIVE：To design an excitation source for endocardial 3D mapping with simple structure and high integration,furthermore,to test the performance of the excitation source through animal experiments.METHODS：Three channel different frequencies （28,30,32 kHz） sine voltage signals were generated based on the direct digital synthesis （DDS） technology and modularization design through three AD9851 chip controlled by single-chip microcomputer STC89C52.The excitation source＇s performance is analyzed by acquisition and processing the localization signal in animal right atrium.RESOULTS AND CONCLUSION：The animal experimental results show that three signals＇ current value can be stable at 1mA and the frequency errors are 0.054%,0.097%,0.056%,respectively,furthermore,voltage signals in three directions can be extracted from the mapping catheter＇s sampling data.The excitation source has little frequency error and higher constant-current performance,and therefore can satisfy the endocardial mapping requirements.