Filtering method of power frequency interference in ECG signals / 生物医学工程学杂志

Electrocardiogram (ECG) signals are susceptible to be disturbed by 50 Hz power frequency in the process of acquisition and conversion. This paper puts forward the improved Levkov algorithm combined with the antisymmetry of sine wave and the characteristic of not--easily mutation of the sine wave amplitude. The improved and the original algorithms were compared with signal to noise ratio (SNR), root mean square error (RMSE) and coincidence of the signals. Based on the experimental comparison, it was concluded that the improved algorithm had better filte-ring functions, because it not only highly coincided with ECG, but also retained certain details of ECG.

Continuous ECG recording for freely moving patients / 生物医学工程学杂志

As more and more people are becoming aged in China and many of them tend to suffer from chronic cardiac problems, the long-term dynamic cardiac monitoring for freely moving patients becomes essential. A new design for continuous ECG recording on the freely moving patients at home and/or at work is proposed here. It is miniature in size, using digital technologies of the low gain amplifier, the high resolution analog to digital converter and the real-time digital filter that features > 100dB input signal dynamic range (ISDR), > 100dB common-mode rejection ratio (CMRR), and < 5microV (RMS) internal noise. The device works continuously more than 24 hours with a pair of AAA batteries, and is capable of storing the recorded data into a storage card. The preliminary tests showed that the P-QRS-T waveforms were captured and displayed smoothly in resting, walking, and activities, making the device useful in monitoring and analyzing for the patients on the move.