In this paper, a standard ECG database (European ST-T Database) is used to analyzed the frequency spectrum of electrocardiogram waveform based on the Welch＇s method of averaging modified periodograms, belonging to the nonparametric model power sepctrum estimation. The final computing results give a general description of the spectral range and the maximal energy segment of ECG waveform, which is helpful to design the hardware circuits of ECG signal extraction and the software algorithm of the waveform recognition such as P wave, QRS wave and T wave.

BACKGROUND: Researches on the diagnosis and detection methods of diabetic autonomic neuropathy(DAN) is very weak at present.OBJECTIVE: To get the data about the degree of autonomic neuropathy by using the nonlinear heart rate variability(HRV) so as to provide clinical evidence for the early diagnosis of DAN.DESIGN: A single sample study.SETTINGS: Computer department in a university; Staff room of medical physics of department of biomedical engineering in a university.PARTICIPANTS: The experiment was completed in the Staff Room of Medical Physics, Department of Biomedical Engineering in the First Military Medical University of Chinese PLA from March to May 2002. Thirty-four diabetic patients, including 22 with DAN complications, were selected from the inpatients of Department of Endocrinology in the Affiliated Nanfang Hospital of the First Military Medical University of PLA, and other 40 normal subjects, who were from the faculty in the First Military Medical University of Chinese PLA and students in the Department of Physical Education, Chinese PLA Institute of Physical Education, were taken as the controls. The R wave to R wave intervals(RRI) time series is sampled and corrected to 512 points for analysis.INTERVENTIONS: Based on the virtual instrumental workbench-LabVIEW, 74 standard adjacent RRI signals were selected from 34 diabetic patients and 40 normal cases, and then analyzed with the method of nonlinear predictability.MAIN OUTCOME MEASURES: Collective and analytical results of the 74 standard adjacent RRI signals.RESULTS: There was no significant difference between the diabetic patients without DAN and the controls by the analysis with normalized mean square error(NMSE) NMSE ( P = 0. 075 ), but the significant difference between the DAN patients and the controls( P = 0. 001) . While significant analysis between the diabetic patients without DAN complications and the controls was significant by the analysis of mean absolute error(MAE) (P = 0. 007 and P = 0. 000), there was also significant difference between the diabetic patients with and without DAN ( P = 0. 001 ).CONCLUSION: Different impaired degree of autonomic nerve system in diabetic patients can result in nonlinear reduction in HRV analysis, but nonlinear predictability analysis can prove the nonlinear model of HRV,. and can also provide important state information of sympathetic and parasympathetic systems so that it can provide reliable evidence for the earlier diagnosis and the prognosis evaluation of DAN.

A software system of the pulse oximeter is presented in this paper. Based on Franklin C, this software system includes three main parts, one part is to automatically regulates the base line of signal, the second part is a controlled integral module,and the third part is a digital signal processing module. As the result, the pulse oximeter is satisfactory to clinical monitoring.

In allusion to the defects of traditional electronic sphygmomanometer in deflation process,this paper puts forward an innovative way which accomplishes the measure of blood pressure during charge process based on oscillometric method.It is proved to be more energy-saving,more subminiature,less measuring time and more stable for individual.

Objective To study non-invasive measurement of reflectance oxygen saturation.Methods Diffusion theory was used to explain the action of light in tissue and deduce reflectance oxygen saturation formula.Then,Reflectance Oxygen Saturation Detection System based on MSP430 was developed and calibrated.Result The calibration result and calibration curve was ascertained and analyzed.Conclusion The formula for detection and measurement of oxygen saturation is put forward by using Reflectance Oxygen Saturation Detection System.

The automatic gain control circuit is designed on the basis of MSP430F149 microcomputer with the chopper amplifier, and then continuous stepless regulation of pulse wave signal is fulfilled. Thus individual variation -induced problems are eliminated such as signal baseline drift and saturation. With this circuit, medical instruments can be portable and low-power-consumption.

Ultrasonic sensors are optimal to the guidance system for the blind.The previous ultrasonic guidance systems acquire the position information of obstacles,and transform it into audio signal or tactile vibration.The system developed in this paper,utilizing programmable gain technique and digital potentiometer,acquires the power of reflected ultrasonic as additional information,and informs the blind with modulated audio signal.In this paper,the studies on programmable gain is described detailed including the hardware structure,the software design and information post processing.

Lives are maintained by enough oxygen.Blood oxygen saturation is one of the important parameters which reflects oxygen concentration in blood.The accurate monitoring of blood oxygen saturation is very important to both physiological research and medical application.At present,dual-wavelength method is widely adopted in noninvasive detection of blood oxygen saturation.Therefore,accurate recognition of peak-to-peak value of pulse waveform is a key process in monitoring blood oxygen saturation.In the paper,LMS self-adaptive arithmetic is applied to processing pulse waveform signal.The ratio of corrective detection is improved by the method.

To investigate dynamic characteristics of the hydrolization lipid phosphatidylinositol(4,5)-bisphosphate(PIP 2 )with the stimulation of epidermal growth factor(EGF),the mathematical model to simulate the metabolizability of PIP 2 is established based on Law of Mass Action and Law of the Quasi-steady-State Approximation.Differential equations of concentration relations between PIP 2 and EGF receptor are formulated,and the effect of the parameters on the changing trend of PIP 2 is analyzed.This mathematical model describes biology characteristics of metabolized PIP 2 and dependency relationships of concentration between key signal producuts.

A novel blood pressure measurement system was designed which based on auscultatory method. And the electret sensor that embedded into the internal instrument can detect the Korotkoff-sound signal directly which is coupled by the cuff and transmitted in the cross connection. The BP values identification algorithm is based on combined detection of Korotkoff-sound and pulse signal, and the products of amplitudes and energies are calculated as the characteristic values of Korotkoff-sound, and the Korotkoff-sound phases are classified and detected by means of clustering of characteristic values, and then BP parameters are determined. The contrast test and statistical analysis showed good consistency and accuracy between the new BP detection method and conventional mercury sphygmomanometer.
Blood Pressure ; Blood Pressure Determination ; instrumentation ; methods ; Equipment Design