ABSTRACT
The amplifier is easy to saturation because of polarization voltage in ambulatory ECG acquisition. The traditional way is using analog high-pass filter to eliminate, but the output tends to have a residue. If upgrading high-pass filter cutoff frequency, it will lead to low frequency distortion of ECG signals. In this paper, a Savitzky-Golay (SG) smoothing filter has been designed by combining the single edge point and the polynomial order , which can fit the polarization voltage components of ECG signals, filter useful components and get drift-free ECG signals by using the subtraction algorithm. The results of ECG filtering experiment verify the feasibility of the SG smoothing filter, and show the filtered ECG signal without any losses of useful components.
Subject(s)
Humans , Algorithms , Amplifiers, Electronic , Electrocardiography, Ambulatory , Methods , Signal Processing, Computer-AssistedABSTRACT
Objective To develop a digital signal processing method for magnetic positioning of electronic capsules according to the theory of multiple alternating magnetic field source electromagnetic positioning, so as to reduce the volume and power consumption of electronic capsules. Method Based on STM32 MCU, software algorithms such as fast digital filtering, peak detection and frequency detection were designed to replace the corresponding analog hardware circuits such as analog filtering, peak detection and comparison circuits. Results The experimental results showed that the average relative error of the peak detection and frequency detection of the digital signal processing system were 1.51％ and 0.28％ , respectively. The linear relationships of theoretical amplification factor and actual amplification factor of the programmable amplifier were basically consistent, and the average ratio difference was 4.51 dB. Conclusions The proposed digital signal processing system can replace some analog hardware circuits, providing a basis for reducing the size and power consumption of electronic capsules.
ABSTRACT
Objective To investigate the application of open beat to beat techniques recording His bundle activity without digital averaging. Methods Recording was performed with very low noise, high gain amplifiers and by analog filtering. 3 brigade amplifiers and 16 bite A/D were connected to a microcomputer by USB. The signal was processed by A pattern recognition plus digital filtering software. The subjects were in a supine position during the recording. Results A prominent waveform was observed between the atrial and ventricular complexes and corresponded to His bundle activity in 46 volunteers. Recordings in 8 patients were compared with records obtained by intracardiac electrode, and a good conformation was seen. Conclusion The noninvasive method of beat to beat surface recording of His bundle activity has broad clinical applicability and high utility for the patients with latent A-V block and eletrophysiologic study.
ABSTRACT
Objective To evaluate a noninvasive method which has been applied on human subjects to observe beat to beat activity of the His bundle potential. Methods Recording was performed with very low noise, high gain amplifiers and by analog filtering. 3-brigade amplifiers and 16-bite A/D were connected to a microcomputer by USB. The signal was processed by a combined pattern recognition and digital filtering software. Results The results of surface monitoring were compared with intracardiac method in 30 patients. The results of non-invasive method were consistent with that interventional method. A prominent waveform was observed between the atrial and ventricular complexes (A, H, V waves), and corresponded to His bundle activity in all patients. Conclusion The noninvasive method of beat to beat surface recording of His bundle activity has broad clinical applicability and high utility for the patients with latent A-V block and eletrophysiologic study.