基于DDS算法的12导联心电信号发生器设计

心电信号发生器是研发智能心电仪器的关键设备,心率连续可变是心电信号发生器研究的难点。提出了一种用DDS(direct digital frequently synthesis)算法合成心率连续可变的多导联心电信号的方法,并在基于ARM的嵌入式实时操作系统uC/OS-II上用软件实现了该方法。首先证明了用软件实现DDS算法产生心电信号的可行性;针对心电信号的频率特点给出了算法的基本参数;并根据DDS算法思想给出了一种查找表(LUT)长度调整的方法;最后分析了本方法误差的主要来源,通过理论推导得出系统误差为26×10-6。实验结果证明本方法行之有效,具有理论和实际意义。

Design of 12 lead ECG signal generator based on DDS arithmetic

ECG signal generator is a key apparatus in the development of intelligent ECG equipment. How to create a consecutive variable heart rate ECG is the difficulty of ECG signal generator. In this paper, a method based on DDS (direct digital frequently synthesis) arithmetic for multi-lead ECG is given, which is realized on the ARM7 processor based real-time operating system uC/OS-II. At first, the thesis proves the feasibility of the method based on DDS arithmetic. The primary parameters of the arithmetic are elicited according to the frequency characteristics of ECG signal. Then, the paper gives out a means to adjust the length of LUT. At last, the main source of the frequency error is analyzed. And theoretical derivation indicates that the system error of the method is 26×10~(-6)Experiment results indicate that the proposed method is effective and has important theoretical and practical values.