Budin N, Abboud S
Biomedical Engineering Department, Faculty of Engineering, Tel Aviv University, Israel.
Comput Biol Med. 1994 Nov;24(6):451-62. doi: 10.1016/0010-4825(94)90043-4.
A real-time multichannel fetal ECG monitor based on a personal computer (PC) and a MOTOROLA DSP56001 Digital Signal CoProcessor (DSP) is introduced. The DSP board is plugged into the PC, which functions as a HOST computer. An analog 8 Leads Interface and Analog to Digital circuits module is connected to the DSP through a synchronous, optical-isolated communication channel. The fetal ECG detection is based on a cross-correlation technique. An averaged maternal ECG waveform is generated using a cross-correlation alignment procedure and a user-defined template. The fetal ECG signals present in the maternal waveform is suppressed during the averaging procedure, since both are uncorrelated. The average maternal ECG waveform is then subtracted from the abdominal real time signals, and maternal-free fetal ECGs signals are obtained, including fetal QRS complexes that coincide with maternal ones. Using the abdominal ECGs signals after subtraction, an averaged fetal waveform is generated. The maternal and the fetal heart rate are calculated during the process. The algorithm described above can be performed in real time on up to eight abdominal ECG traces by the DSP, and the desired results are passed to the HOST PC, to be stored and displayed. Electrodes positioning procedures for detecting the fetal QRS complexes with the best signal to noise ratio are not needed. Using the multichannel system, the user can select the best channel for fetal QRS detection, and accurate results for the heart rate signal are obtained. Averaged fetal waveforms are obtained from all the leads.
介绍了一种基于个人计算机（PC）和摩托罗拉DSP56001数字信号协处理器（DSP）的实时多通道胎儿心电图监测仪。DSP板插入PC，PC作为主机。一个模拟8导联接口和模数转换电路模块通过同步光隔离通信通道连接到DSP。胎儿心电图检测基于互相关技术。使用互相关对齐程序和用户定义模板生成平均母体心电图波形。由于两者不相关，在平均过程中母体波形中存在的胎儿心电图信号被抑制。然后从腹部实时信号中减去平均母体心电图波形，得到无母体的胎儿心电图信号，包括与母体心电图信号重合的胎儿QRS复合波。利用减法后的腹部心电图信号生成平均胎儿波形。在此过程中计算母体和胎儿的心率。上述算法可由DSP对多达八个腹部心电图通道实时执行，并将所需结果传递给主机PC进行存储和显示。不需要用于检测具有最佳信噪比的胎儿QRS复合波的电极定位程序。使用多通道系统，用户可以选择用于胎儿QRS检测的最佳通道，并获得心率信号的准确结果。从所有导联获得平均胎儿波形。
