CN110731764A

CN110731764A - pulse detection system

Info

Publication number: CN110731764A
Application number: CN201911031734.5A
Authority: CN
Inventors: 刘玉菲; 陈璐; 张楠; 杜基赫
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2019-10-28
Filing date: 2019-10-28
Publication date: 2020-01-31

Abstract

The invention discloses an pulse detection system, which comprises a pulse signal acquisition module, a signal conditioning circuit, a data acquisition module and a data processing module, wherein the pulse signal acquisition module is used for acquiring pulse signals and converting the acquired pulse signals into charge signals, the signal conditioning circuit is connected with the pulse signal acquisition module and is used for pre-amplifying the charge signals and generating pre-amplified voltage signals, the data acquisition module is connected with the signal conditioning circuit and is used for sampling the pre-amplified voltage signals and generating digital signals, and the data processing module is connected with the data acquisition module and is used for processing the digital signals and transmitting the generated second digital signals representing pulse data to an upper computer in a wired or wireless manner.

Description

pulse detection system

Technical Field

The invention relates to the technical field of human pulse detection instruments, in particular to pulse detection systems.

Background

With the development of new times in China, the living standard of human beings is higher and higher, but at present, many countries face the problem of population aging, and the aging speed of China is the first of all more global. The aging is continuously increased to make various aspects such as the country, the society and the like pay more attention to the health of the old, and corresponding health services must be continuously implemented and perfected.

Since the pulse wave of human body contains abundant physiological and pathological information of human body, it is indispensable examination items for measuring pulse for patients, and the pathological information of human body is extracted from the pulse wave, which can be used as an auxiliary means for clinical diagnosis and treatment, from ancient times to now, the inquiry of traditional Chinese medicine is a means of diagnosis by "feeling pulse", so the importance of pulse wave can be seen, along with the development of material technology and electronic technology, the precision of pulse wave sensor is not continuously improved, the information of pulse wave is recorded from handwriting to PC end, the research of pulse wave is also gradually deepened, the results of a large number of clinical measurements prove that the waveform characteristics of pulse wave are closely related to vascular diseases, the information of various aspects such as amplitude, frequency and the like of pulse wave can be recorded to the physiological and pathological characteristics of human vascular system, and through a large number of clinical experiments and data analysis, medical workers can utilize the correlation of pulse wave and parameters to evaluate the health condition of human body by utilizing the piezoelectric film, and the flexibility of the film, the PVDF film has the characteristics of closely matched with the medical film, the piezoelectric film, the.

Choi et al (Choi S, Jiang Z.A wearable heart disease sensor system for analyzing the sleep condition [ J ]. Extra Systems with Applications,2008,35(1-2): 317-. However, these methods have the disadvantage that the change of sleeping posture and the vibration of surrounding objects can generate noise during sleeping, and if the noise is not filtered, the obtained result is also inaccurate.

Pulse sensors (VS-1500A) from Futian corporation, a large medical device manufacturer in Japan, can detect arteriosclerosis, and when the device is used, a measuring device similar to a bandage is wound on two wrists and two ankles, and the degree of arteriosclerosis is measured by measuring the speed of the pulse from the heart to the wrists and the ankles, indicates that the propagation speed of the pulse is increased when the arteriosclerosis is increased, but the device is tens of thousands of yen in price and weighs several kilograms, and the device is not suitable for being purchased by families.

Jinguanchang et al (jinguanchang, at vast, university of qinghua, 1998, 38(2):21-24) at the university of qinghua uses sensor array for multi-point pulse test to detect pulse patterns of cun, guan and chi parts separately, and uses computer software to perform spectrum analysis on pulse waveform to verify that the spectral lines of the three parts are different and represent different physiological information, which can be combined with pulse diagnosis of traditional Chinese medicine to provide more accurate and detailed information for doctor. But the cost is high and the operation is complex.

The PVDF-based pulse sensor designed by the Chenopodium (Chenopodium. PVDF-based piezoelectric film pulse sensor design [ D ]. Dalian: university of Caliper, 2011) of the university of Chongchii realizes the measurement of the pulse, but does not perform back-end signal processing and analysis detection.

The PVDF piezoelectric film is novel high-molecular polymer type sensing materials, and has the advantages of light weight, softness, high frequency response, high sensitivity, good processing performance, wide frequency response, high mechanical property strength and the like as a new piezoelectric material.

The existing medical diagnosis system for pulse pathological detection has various problems, such as low precision, large noise, no relevant index analysis to pulse waveform, signal distortion, large volume and high cost.

Therefore, it is important for those skilled in the art to provide real-time pulse detection and analysis systems that have high accuracy, low noise, low cost, portability, and capability of analyzing pulse wave indicators, and thus are used as clinical and therapeutic aids.

Disclosure of Invention

In order to solve or more problems of low precision, large noise, high cost, large volume, complex operation and the like of the existing pulse detection and analysis system, the invention innovatively provides pulse detection and analysis systems, which comprise:

the pulse signal acquisition module is used for acquiring pulse signals and converting the acquired pulse signals into charge signals, wherein the acquisition of the pulse signals adopts a piezoelectric film sensor;

the signal conditioning circuit is connected with the pulse signal acquisition module and is used for pre-amplifying the charge signal to generate a pre-amplified voltage signal;

the data acquisition module is connected with the signal conditioning circuit and used for sampling the pre-amplified voltage signal to generate an th digital signal;

and the data processing module is connected with the data acquisition module and is used for processing the th digital signal and transmitting the generated second digital signal representing the pulse data to the upper computer in a wired or wireless way.

Further , the signal conditioning circuit includes:

the differential charge amplification module is used for receiving the charge signal, converting the charge signal into an th voltage signal and amplifying the th voltage signal to obtain a second voltage signal;

and the voltage amplification module is used for amplifying the second voltage signal to obtain a third voltage signal.

, the signal conditioning circuit further comprises:

and the Butterworth low-pass filter is used for filtering noise in the third voltage signal to obtain a fourth voltage signal.

Further , the butterworth low pass filter is constructed using a combination of active and passive.

, the signal conditioning circuit further comprises:

and the power frequency wave trap is used for filtering power frequency interference in the fourth voltage signal to obtain a fifth voltage signal.

, adopting a 50Hz power frequency wave trap with narrow stop band, high quality factor Q value, attenuation higher than-50 dB at 50Hz, and double-T double-following filter.

, the data acquisition module is a high precision data acquisition module with 12 bits of high precision acquisition, voltage resolution of 0.8mV, and low noise of 0.2 mV.

, the data processing module adopts STM32F103C8T6 singlechip minimum system, the CPU maximum clock frequency is 72MHz, and the low power consumption is 0.02W.

, the piezoelectric film sensor is a PVDF film sensor.

, the device also comprises a pulse analysis module based on Labview as an upper computer for carrying out data analysis and result presentation according to the received digital signals, wherein the pulse analysis module comprises or more modules of a pulse waveform analysis detection module, a pulse velocity waveform analysis detection module and a pulse acceleration waveform analysis detection module.

, the Labview-based pulse analysis module has a data real-time receiving module error of 1 μ s and a frequency counting module error of 1 μ s, and the host computer has the functions of detecting the pulse frequency, the peripheral vascular resistance response index, the peripheral atherosclerosis index, the vascular tension and the vascular aging index of the pulse wave in real time, and can effectively analyze the pathological information contained in the pulse wave.

The invention has the beneficial effects that: the pulse real-time detection is realized, the case analysis is carried out, the cost is low, the size is small, the operation is simple, and the device is suitable for home preparation. The system has the outstanding advantages of high sensitivity, high precision, comprehensive functions, intelligence and the like.

Drawings

FIG. 1 is a block diagram of preferred embodiments of the pulse detection system.

FIG. 2 is a block diagram of another preferred embodiments of the pulse detection system according to the present invention.

Fig. 3 is a schematic view of a piezoelectric film according to a preferred embodiment of the present invention.

Fig. 4 is a schematic circuit diagram of a differential charge amplifying module according to a preferred embodiment of the present invention.

Fig. 4-1 is a general band diagram of a differential charge amplification module in accordance with a preferred embodiment of the present invention.

Fig. 4-2 is a graph of the differential charge amplification block cutoff frequency of fig. 4-1.

FIG. 5 is a block diagram of a pulse analysis module according to a preferred embodiment of the present invention.

Fig. 6 and 7 are schematic diagrams of pulse waveforms according to the preferred embodiment of the invention.

FIG. 8 is a graph comparing a pulse waveform and a pulse acceleration waveform according to a preferred embodiment of the present invention.

Detailed Description

The pulse detection systems according to the present invention will be explained and explained in detail with reference to the drawings attached to the specification.

Fig. 1 is a block diagram of preferred embodiments of a pulse detecting system 1, as shown in fig. 1, this embodiment discloses pulse detecting systems 1, and the pulse detecting system 1 includes a pulse signal collecting module 2, a signal conditioning circuit 3, a data collecting module 4 and a data processing module 5, the pulse signal collecting module 2 is used for collecting pulse signals and converting the collected pulse signals into charge signals, wherein a piezoelectric film sensor is used for collecting the pulse signals, the signal conditioning circuit 3 is connected with the pulse signal collecting module and is used for pre-amplifying the charge signals and generating pre-amplified voltage signals, the data collecting module 4 is connected with the signal conditioning circuit 3 and is used for sampling the pre-amplified voltage signals and generating th digital signals, the data processing module 5 is connected with the data collecting module 4 and is used for processing the th digital signals and transmitting second digital signals representing pulse data generated by wire or wirelessly to an upper computer.

Fig. 2 is a block diagram of another preferred embodiments of the pulse detection system 1 according to the present invention, and as shown in fig. 2, the signal conditioning circuit 3 further includes a differential charge amplifying module 31, a voltage amplifying module 32, a butterworth low-pass filter 33, and a power frequency wave trap 34.

The pulse signal acquisition module 2 acquires a pulse signal, converts the acquired pulse signal into a charge signal and sends the charge signal to the differential charge amplification module 31, the differential charge amplification module 31 converts the received charge signal into an -th voltage signal, amplifies a -th voltage signal to obtain a second voltage signal, and sends the second voltage signal to the voltage amplification module 32, the voltage amplification module 32 amplifies the received second voltage signal to obtain a third voltage signal, sends the third voltage signal to the Butterworth low-pass filter 33, the Butterworth low-pass filter 33 filters noise in the received third voltage signal to obtain a fourth voltage signal, and sends the fourth voltage signal to the data acquisition module 4, the data acquisition module 4 samples the received fourth voltage signal to obtain a -th digital signal, sends the 25-th digital signal to the data processing module 5, the data processing module 5 processes the received -th digital signal to obtain a second digital signal, and transmits the second digital signal to an upper computer in a local or wireless manner, and the Butterworth understanding that the Butterworth low-pass filter 33 and the optional Butterworth low-pass filter 34 are wires.

The pulse signal acquisition module 2 comprises a piezoelectric film sensor. Fig. 3 is a schematic view of a piezoelectric film 21 of a preferred embodiment of the present invention in an x-y-z coordinate system. The pressure generated by the radial artery blood acts on the piezoelectric film 21, and the pulse signal acquisition module 2 converts the mechanical energy into electric energy. The piezoelectric equation is:

in the formula D_iFor the potential shift (C/m ^2) generated in the i direction, the subscript i is the output direction of the charge amount, and when the charge amount is output in the X, Y, Z direction, i is 1,2, 3. T is_jIs the stress (N/m ^2) received in the j direction, wherein the j is 1,2,3 …,6, the force in the 1,2,3 direction is the positive stress, and the force in the 4,5,6 direction is the shearing stress. d_ijSince there are only pairs of electrodes, the displacement D can be obtained only in the Z direction₃Shear force T₄、T₅、T₆Induced electrical shift D₁、D₂Is not measurable. Thus, the piezoelectric equation is:

D₃＝d₃₁T₁+d₃₂T₂+d₃₂T₃

the present invention relates to a pulse signal measuring device, and more particularly, to a pulse signal measuring device, which comprises a piezoelectric film sensor of kinds, which is a dynamic strain sensor having a sensitivity sufficient to detect a human pulse through the skin, and in embodiments, the piezoelectric film sensor employs a PVDF piezoelectric film sensor, preferably, flexible PDMS is used as a base structure of the PVDF piezoelectric film sensor, and since the PVDF piezoelectric film has unique flexibility to match the human skin, high sensitivity, fast response, and high comfort, the piezoelectric film of the present invention employs a PVDF film, and the present invention is used to measure a pulse signal of a radial artery of a wrist of a human, and as to the area of the PVDF film, the effect of detecting the pulse signal is lost if it is too small, and the sensitivity is low if it is too large, and it is easily disturbed, and preferably, the area of the PVDF film is determined by measuring the area of the radial artery of the wrist of the human, preferably, the PVDF film has a rectangular shape of 2.5cm × 1.5cm, the upper and lower surfaces of the PVDF film are covered with positive and negative electrode layers, respectively, and preferably, positive and negative electrode layers and positive and negative electrode layers are connected by means of rivets, and a wrist band is fixed to a wrist band, and a wrist band is used to collect a medical wrist band, and a wrist band is preferably, and a wrist band is attached to collect a wrist band is attached to a wrist band.

The signal transmission line of the piezoelectric film sensor is preferably a shielded cable. The introduction of noise can be greatly reduced by using the shielded cable, and the length of the signal transmission line can be increased.

The differential charge amplification module adopts a differential input charge amplifier to convert charge signals generated by the PVDF flexible film sensor into voltage signals, FIG. 4 is a circuit schematic diagram of the differential charge amplification module 31 according to embodiments, the differential charge amplification module 31 preferably adopts pre-amplifiers 311 with high input impedance and deep negative feedback, and adopts differential input to greatly improve the common mode rejection ratio, greatly weaken noise introduced by the piezoelectric film pulse sensor, improve the signal-to-noise ratio, ensure the integrity and high precision of pulse signals so as to better analyze pathological information contained in the pulse, and impedance analysis tests show that the frequency range of 0-15Hz is 1cm²The resistance value of the PVDF film is about 10-20M omega, so that the internal impedance is very high, and impedance matching is required to ensure no distortion of signals; since the charge signal is weak, the charge amplifier connected to the pulse signal acquisition module 2 must have very high input impedance and very low bias current. Since the input impedance of the charge amplifier is high, the charge generated by the PVDF sensor is only applied to the feedback capacitor C_fCharging is carried outThe output voltage of the charge amplifier is V_OUT＝-Q/C_f. Wherein Q is the amount of charge, C_fSince the accuracy of the output voltage is determined for the feedback capacitance, it is necessary to use a high-accuracy capacitance as the feedback capacitance. And because C is usually added to avoid saturation of the charge amplifier due to long charging time_fAnd resistors R_fIn parallel, R_fThe dc component in the circuit can be stabilized. Considering a pulse frequency range of 0-10Hz, the value C is preferably chosen_f＝1nF,R_fAnd 10M, the bandwidth requirement required by the low-frequency pulse signal is met. By Multisim simulation analysis, fig. 4-1 shows a band diagram of the differential charge amplification module 31, which shows that the amplification factor is about 20 times. Fig. 4-2 is a graph of the cut-off frequency of the differential charge amplification block 31, the cut-off frequency being 15.94 Hz. The charge amplification module adopts differential input, so that the common mode rejection ratio is greatly improved, and the noise introduced by the sensor is reduced. The operational amplifier of the charge amplification module preferably adopts an LF353M operational amplifier produced by TI company, has the advantages of low input bias current (50pA), low input voltage noise (25nV), low input offset current (0.01pA), low temperature drift offset voltage (5 uV/DEG C), large bandwidth (4MHz) and the like, and has very large input resistance (10 MHz)¹²Omega), can realize impedance matching with the internal resistance of the piezoelectric sensor, can be applied to amplification of weak small signals in medical electronics.

The voltage amplification module 32 amplifies the voltage signal after pulse conversion, so that the subsequent high-precision data acquisition module can conveniently acquire data. The high-precision data acquisition module is used for converting the amplified pulse analog electric signals into digital signals, so that the pulse data can be analyzed and processed conveniently in the follow-up process.

The data acquisition module 4 can generally acquire voltage values of 0-3.3V, the voltage amplification module 32 is required to amplify th voltage signals in order to meet the acquisition requirements of the data acquisition module 4, preferably, the amplification factor of the voltage amplification module 32 is 1-100 times, the voltage amplification module 32 can adopt ADA4062 integrated operational amplifier, the sensitivity of the operational amplifier is designed to be 1-100 times, the low output offset voltage is 5 muV, the gain bandwidth is 1.4MHz, preferably, the voltage amplification module 32 adopts OP27 operational amplifier as an operational amplifier chip, the offset voltage is as low as 25 muV, the maximum drift is 0.6 muV/DEG C, the operational amplifier is extremely low in noise, the low 1/f noise turning frequency (2.7Hz) and high in gain (180 ten thousand), the low level signals can be amplified with accurate high gain, the low level signals can be amplified with + -10 nA by using a bias current elimination circuit, the circuit can generally keep IB and IOS within the whole military temperature range, the IB and IOS respectively at +/-20 kHz, 15nA, the power source output voltage values can be well as high-grade power source amplification, the maximum load gain amplification voltage amplification ratio can be guaranteed, the acquisition efficiency of the power amplifier is preferably, the power amplifier is high in the power amplifier is 120 nA, the power amplifier is guaranteed, the maximum load amplification module can be guaranteed, the power amplifier is 120 nA, the power amplifier is good, the high-load amplification module can be guaranteed, the high-load-frequency amplification module can be guaranteed, the high-frequency amplification module.

Although the pulse signal is mainly in the third voltage signal amplified by the voltage amplifying module, the pulse signal is mixed with a lot of noise and other signals which are irrelevant to measurement, such as skin electrostatic interference at the wrist of a human body, so that the measurement precision is influenced, the noise is very random and is difficult to be directly separated from the time domain, but the noise power is limited and is regularly distributed in a certain frequency band in the frequency domain according to .

The power frequency trap 34 preferably filters low-frequency interference, namely 50Hz power frequency interference, so as to ensure the integrity and high precision of pulse signals, the power frequency interference is ubiquitous in our lives, because the mains supply can emit energy outwards in the form of electromagnetic waves in the transmission process, and further influences electronic equipment used by us, because the standard frequency of the alternating current supplied by China is 50Hz, the main frequency of the power frequency interference noise is near 50Hz, a corresponding trap filter is required to be used for filtering, and steps further, the power frequency trap 34 adopts the 50Hz power frequency trap 34, and has the characteristics of narrow stop band, high quality factor Q value and attenuation higher than-50 dB corresponding to 50 Hz.

The frequency of the pulse signal is 0-10Hz, and the sampling rate is more than 10 times of the sampled signal, so that the requirement is met. The data acquisition module 4 is preferably a high precision data acquisition module with 12-bit high precision acquisition, a voltage resolution of 0.8mV, and a low noise of 0.2 mV. The sampling rate of the data acquisition module 4 is preferably 200SPS, which not only can ensure the integrity of the acquired signals, but also has small data volume, is convenient for the rapid processing of an upper computer, and reduces the load of a CPU (central processing unit) at the PC end. In order to obtain the signal-to-noise ratio as high as possible when measuring small signals and ensure the high precision and integrity of the acquired signals, an average smooth filtering algorithm is used in the analog-to-digital conversion acquisition.

The data processing module 5 is used for processing data sent by the data acquisition module 4, and then transmitting the processed data to an upper computer in real time through a wireless transmission module, the data processing module has strong anti-interference performance and cannot lose data in the transmission process, and the integrity of information is ensured.

The system preferably further comprises a transmission module, wherein the transmission module is used for transmitting data sent by the data processing module 5 to an upper computer, the data transmission mode of the transmission module can be wired communication or wireless communication, step is carried out, the data transmission mode can be USB communication, preferably Bluetooth communication, step is carried out, the wireless transmission module comprises a Bluetooth module of the Xin Chida company, wireless transmission is carried out by utilizing a USART protocol, the interface characteristic is TTL, a 3.3V/5V power supply is compatible, the baud rate is set to be 115200, the communication distance is 15-20 meters, and the power consumption in communication is about 3 mW.

Preferably, the system further comprises a power module for supplying power to the other modules. Since the pulse detection system needs +5V voltage for charging and discharging and the signal conditioning circuit needs +/-5V voltage for supplying power, the power supply module preferably comprises a DC-DC power converter. The DC-DC power converter is used to convert a +5V voltage to ± 5V. The DC-DC power converter has the following advantages: the voltage of the input end and the voltage of the output end are smooth direct current and have no alternating current harmonic component; the output impedance is zero; the rapid dynamic response is realized, and the inhibition capability is strong; high efficiency and miniaturization. However, the output ripple of the DC-DC power converter is large, and therefore, the power module preferably includes a filter circuit and an anti-reverse switch circuit.

The upper computer can be, for example, a pulse detection module based on Labview, which is used for carrying out data analysis and result presentation according to received digital signals and comprises or more modules of a pulse waveform analysis detection module, a pulse velocity waveform analysis detection module and a pulse acceleration waveform analysis detection module.

FIG. 5 is a block diagram of a pulse analysis module according to a preferred embodiment of the present invention, as shown in FIG. 5, the system further includes a Labview-based pulse analysis module 6 as an upper computer, the pulse analysis module 6 includes a real-time data receiving module 61, an abnormal peak detection module 62, a pathology analysis module 64, and an alarm module 63, and , the pathology analysis module 64 includes a Pulse Waveform (PWA) analysis detection module 641, a pulse velocity waveform (PWV) analysis detection module 642, and a pulse acceleration waveform (APG) analysis detection module 643, the real-time data receiving module 61 compiles a corresponding receiving format according to a data format transmitted by a lower computer, the real-time data receiving module 61 receives data transmitted by a wireless transmission module or a wired transmission module, the abnormal peak detection module 62 is configured to compare the data received by the real-time data receiving module 61 with a set threshold, and when the data received by the real-time data receiving module 61 exceeds the set threshold, sends an alarm indication of a peak abnormal alarm to the alarm module 63, and sends a peak abnormal alarm indication after the alarm module receives the peak abnormal alarm indication.

The pulse velocity waveform (PWV) analyzing and detecting module 642 is used for analyzing whether the heartbeat frequency is normal, and when the heartbeat frequency is abnormal, the pulse velocity waveform (PWV) analyzing and detecting module 642 sends an alarm indication of abnormal heartbeat frequency to the alarm module 63. After the alarm module 63 receives the alarm indication of abnormal heartbeat frequencyAnd sending a heartbeat frequency abnormity alarm prompt. The pulse velocity waveform (PWV) analyzing and detecting module 642 is used for detecting a time interval between adjacent peaks of a pulse velocity waveform within a set time, removing a maximum value and a minimum value in the time interval, then taking an average value of the peak time interval, and determining whether the heart rate is normal according to the average value of the peak time interval. The set time is preferably 20 s. The pulse velocity waveform (PWV) analysis detection module 642 calculates the average of the time intervals by detecting N time intervals between adjacent peaks of the pulse velocity waveform over 20s, removing the maximum and minimum values in the time intervals, and then calculating:

Δ T is the time interval, Δ T_MAXIs the maximum value in the time interval, Δ T_MINIs the minimum value in the time interval. Namely, the number of heartbeats per minute is:

when the heartbeat frequency per minute exceeds the heartbeat rated range, the heartbeat frequency is abnormal, the alarm module 63 sends out an alarm prompt, the heartbeat rated value can be set and changed according to a user, the frequency of the pulse is influenced by age and gender, the frequency of the infant is 140 times per minute, the frequency of the infant is 90-100 times per minute, the frequency of the child is 80-90 times per minute in the school age, and the frequency of the adult is 70-80 times per minute, in addition, the pulse can be increased when the infant moves and is excited, the pulse is slowed down when the infant is in rest sleep, the pulse rate of the adult exceeds 100 times per minute and is called tachycardia, the frequency of the adult is lower than 60 times per minute and is called bradycardia, preferably, the heartbeat rated range is 60-100 times per minute, the pulse rate waveform (PWV) analysis and detection module 642 updates the heartbeat frequency of times in real time every 20 seconds, and the error is within.

The Pulse Waveform (PWA) analysis and detection module 641 is used for analyzing whether the peripheral vascular resistance response index and the peripheral atherosclerosis index are normal, if the peripheral vascular resistance response index is abnormal or the peripheral atherosclerosis index is abnormal, the Pulse Waveform (PWA) analysis and detection module 641 correspondingly sends an alarm indication of the abnormal peripheral vascular resistance response index or the abnormal peripheral atherosclerosis index to the alarm module 63, and after the alarm module 63 receives the alarm indication of the abnormal peripheral vascular resistance response index or the abnormal peripheral atherosclerosis index, the alarm indication of the abnormal peripheral vascular resistance response index or the abnormal peripheral atherosclerosis index is correspondingly sent out.

FIGS. 6 and 7 are schematic diagrams of Pulse Waveforms (PWA) in an x-y coordinate system. As shown in fig. 6, the peripheral vascular resistance response index is calculated as:

wherein IPA is peripheral vascular resistance response index, A₁、A₂The corresponding area in FIG. 6, as shown in FIG. 7, the pulse wave shape (PWA) reflects the motion process of the heart, th peak is high because the heart contracts and outputs blood outwards until the artery is scratched, which generates the pulse peak at the wrist, and drops to th concave point because the heart relaxes and blood returns, but due to the blockage of the valve, the pulse wave shape is reduced to and then rebounds to form the second peak, the peripheral atherosclerosis index is calculated as:

where AI is the peripheral atherosclerosis index and i, j are the corresponding peak heights in FIG. 7.

The pulse acceleration waveform (APG) analysis detection module 643 is used to analyze whether the vascular tone and vascular aging index are normal. The pulse acceleration waveform (APG) analysis and detection module 643 is configured to derive the pulse velocity waveform (PWV) and convert the derived pulse velocity waveform (PWV) into the pulse acceleration waveform (APG), and determine the vascular aging index according to the pulse acceleration waveform (APG). FIG. 8 is a diagram illustrating a comparison between the Pulse Wave (PWA) and the pulse acceleration wave (APG) in the x-y coordinate system. As shown in fig. 8, the calculation formula of vascular tone is:where AGT is the vascular tone and d, a are the corresponding peak heights in FIG. 8. Calculation of blood vessel aging indexThe formula is as follows:

where AGI is the vascular aging index and a, b, c, d, e are the corresponding peak heights in FIG. 8. If the vascular tone or the vascular aging index is abnormal, the alarm module 63 sends out an alarm prompt for abnormal vascular tone or abnormal vascular aging index.

The intelligent medical bracelet pulse diagnosis system has the advantages of low power consumption, small volume, low cost and the like, can be used as novel intelligent auxiliary medical equipment, has good practicability and market potential, and accords with the future development direction.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and simplifications made in the spirit of the present invention are intended to be included in the scope of the present invention.

Claims

1, pulse detection system, comprising:

2. The pulse detection system of claim 1, wherein the signal conditioning circuit comprises:

3. The pulse detection system of claim 2, wherein the signal conditioning circuit further comprises:

4. The pulse detection system of claim 2, wherein the butterworth low pass filter is constructed using a combination of active and passive.

5. The pulse detection system of claim 2, wherein the signal conditioning circuit further comprises:

6. The pulse detection system of claim 1, wherein the data acquisition module is a high precision data acquisition module with 12 bits of high precision acquisition, a voltage resolution of 0.8mV, and a low noise of 0.2 mV.

7. The pulse detection system of claim 1, wherein the data processing module adopts a STM32F103C8T6 single chip microcomputer minimum system, the CPU maximum clock frequency is 72MHz, and the low power consumption is 0.02W.

8. The pulse detection system of of claims 1-7, wherein the piezoelectric film sensor is a PVDF film sensor.

9. The pulse detection system of any of claims 1-7, further comprising:

the pulse analysis module based on Labview as the upper computer is used for carrying out data analysis and result presentation according to the received digital signals and comprises or more modules of a pulse waveform analysis detection module, a pulse velocity waveform analysis detection module and a pulse acceleration waveform analysis detection module.

10. The pulse detection system according to claim 9, wherein the Labview-based pulse analysis module has a data real-time receiving module error of 1 μ s and a frequency counting module error of 1 μ s, and the host computer has functions of detecting the pulse frequency of the pulse wave, the peripheral vascular resistance response index, the peripheral atherosclerosis index, the vascular tone and the vascular aging index in real time, and can effectively analyze pathological information contained in the pulse wave.