The Study On HRV Sampling And Power Spectrum Analyzing

Heart rate variability(HRV) is a convenient window to study the autonomic nervous system of human body. It is a focus of studying cardiac disease in clinic.On the basis of the current study on real-time HRV collection and later processing home and abroad, ECG signal sampling interface amplifier is designed, It is simulated in Protel and Matlab. The further study on the effect of component parameter change for filter is done in the paper. It shows that the design is correct.Writing a software for real-time collecting .displaying. saving, this software can set sampling frequency and time ,the maximal frequency is lOOOHz. 50Hz interference is filtered by using digital notch filter.In this paper, digital Low pass filter is designed. AR model algorithm and FFT algorithm for resolving power spectrum is compared as well. It shows that AR model algorithm is better than FFT method.Analyzing 15 minute HRV(sit) of 23 healthy persons by using AR and FFT method. VLF%. LF%. HF% is tally with these 2 methods(same sex and same age segment).With the increasing of age(>20) , LF/HF. VLF/HF computed by using the 2 method is increasing , this is tallied with clinic.Analyzing 5 minute HRV(decubitus) of 19 healthy persons by using AR and FFT method, we found that VLF%. LF% by using 2 method is different, but HF% is tallied (same sex and same age segment). It is infered signal length is short, the spectrum resolving power is low by using FFT method, so the VLF% and LF% by using 2 method has great difference. The VLF/HF by using AR presents trend of increasing, this is tallied with clinic.Analyzing 5 minute HRV(decubitus) for 4 myocardial ifchemia sickness by using AR and FFT. We found that TF and VLF/LF by using the 2 methods are great different with healthy person. More than 15 minute signal should be sampled for analyzing spectrum.Analyzing 5 minute HRV(decubitus) for 10 hyperthyroibism sickness by using AR and FFT. We found that VLF/LF of hyper thyroibism sickness by using the 2 methodsinare high than healthy person.Study HRV WD, when using Choi-Williams window to restrain cross disturb, setting filter parameter a = 0.05. It is proved the effect is good. With 3D figure we can know HRV time-frequency distribution and the information of frequency change with time, while this information can not be gotten only in spectrum region. A doctor can find different spectrum distribution at each time segment, and can also look over frequency field corresponding time domain information. Analyzing real HRV, proving the every segment power(high frequency> low frequency) of projection in frequency axis is times with the every segment power by using FFT , the LF/HF by using 2 method is primarily sameness. 3D figure is a trenchancy tool for doctor to look over the relation between time and frequency.