MSP430 Applicationin the medical equipment industry (7)
source: icbuy million core time: 2012-04-05-
ECG signal Software digital filter
Since the ECG signal will inevitably mixed with 50Hz interference, ECG signals simultaneously obtained from the human body contains baseline drift caused by the skin impedance amplifier, respiration and temperature drift, but only rely on hardware is difficult to be the ideal filter, so the software digital filtering method. Figure 6 shows the simulation results on the noisy ECG signal filter 50Hz frequency interference by using FFT method with MATLAB. Experimental raw data from MIT/BIH ECG database of a waveform. The experiment is the rectangular window analog filter, in the recovery time domain signal when there will be ringing effect, so the selection of appropriate window function according to the needs in the actual use.
From the filter and the effect of treatment, fast Fu Liye transform can get all the spectrum signal, easy to handle, window function and the choice of 50Hz shift, there is a good filtering effect. The adaptive template method and mathematical morphology filtering rules are applied and removed in a 50Hz power line interference and baseline drift removal and high frequency noise. The system will be more than three kinds of filtering methods used in combination, when the need to display the ECG waveform on the LCD screen when using the adaptive template method and mathematical morphology method, the data is transmitted to the PC machine can be used for fast Fourier transform method for accurate processing of ECG signal.
electrocardiogram machine PC client software development of
ECG machine designed in this paper has to expand the function of the system based on PC Visual software development environment C++6.0 prepared by the. The electrocardiograph is connected with the PC, start the Windows ECG data acquisition program to see real-time ECG acquisition on a computer screen, PC signal display interface as shown in figure 7.
Conclusion
ECG machine designed in this paper uses the 24 bit high performance analog-to-digital converter chip MSP430FG4616 of TI company and 16 channel low noise delta-sigma architecture, ECG signal can accurately obtain ECG characteristics and their changes, and can be displayed through the MCU control LCD screen graphically and storage, a prospective study for the realization of family medical remote diagnosis. Compared with conventional design, the system has the characteristics of stable performance, high precision, strong anti-interference ability, has the good application prospect.
