A new type of high-precision monitor

Abstract

The present invention provides a new type of high-precision monitor, including a non-invasive blood oxygen module, a non-invasive blood pressure module, and an electrocardiogram, respiration, and body temperature module. The non-invasive blood oxygen module is used to monitor the blood oxygen saturation in human blood. The non-invasive blood oxygen module includes: a power supply part, an analog part, and a digital part; the non-invasive blood pressure module includes a gas circuit part, an analog part, an analog-to-digital conversion part, a central processing unit, and a digital part; the electrocardiogram, respiration, and body temperature module includes an electrocardiogram monitoring part, a respiration monitoring part, and a body temperature monitoring part. The present invention can accurately measure human blood oxygen, blood pressure, electrocardiogram, respiration, and body temperature, and the measurement method is simple and easy to operate.

Description

Technical Field

[0001] The present invention relates to the field of medical monitoring, and in particular to a novel high-precision monitoring instrument. Background Art

[0002] With the improvement of social medical level, more and more multi-parameter monitors have been widely used in hospitals. Doctors use monitors to monitor patients' vital signs such as ECG, respiration, blood oxygen saturation, pulse rate, body temperature, non-invasive blood pressure, invasive blood pressure, carbon dioxide, etc. The existing monitors have certain problems in measurement accuracy due to various design deficiencies, and cannot accurately and quickly measure the various physiological parameters of the tester. Summary of the invention

[0003] 1. Purpose of the present invention:

[0004] In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a new type of high-precision monitor, which can accurately measure human blood oxygen, blood pressure, electrocardiogram, respiration and body temperature, and the measuring method is simple and easy to operate.

[0005] (II) Technical solution of the present invention:

[0006] 1. The present invention discloses a novel high-precision monitor, which comprises a non-invasive blood oxygen module, a non-invasive blood pressure module, and an electrocardiogram, respiration and body temperature module;

[0007] The non-invasive blood oxygen module is used to monitor the blood oxygen saturation in human blood. The non-invasive blood oxygen module includes: a power supply part, an analog part, and a digital part;

[0008] The power supply part in the non-invasive blood oxygen module is used to supply power to the non-invasive blood oxygen module;

[0009] The analog part in the non-invasive blood oxygen module is used to monitor the human pulse wave signal and adjust the pulse wave signal amplitude to the required range. The analog part in the non-invasive blood oxygen module is mainly composed of a blood oxygen probe driving circuit, a signal amplification circuit, a signal separation circuit and an adaptive amplification circuit; the blood oxygen probe driving circuit is used to control the alternating light emission of the blood oxygen probe light emitting diode. The blood oxygen probe driving circuit adopts the SGM3005XMS dual-channel analog switch integrated chip combined with software to realize the control of the light emitting diode; the signal amplification circuit is used to convert the current signal obtained by the photosensitive diode of the blood oxygen probe into a voltage signal through the circuit, and then output it to the lower circuit. The operational amplifier SGM8634 is used in the signal amplification circuit to convert the current signal obtained by the photosensitive diode of the blood oxygen probe into a voltage signal; the adaptive amplification circuit is used to adjust the pulse wave signal amplitude to the required range, and the VDAC0 bias voltage is set in the adaptive amplification circuit;

[0010] The digital part of the non-invasive blood oxygen module is used to ensure the normal operation of the system function and the communication between the system and the inside and outside of the system. The digital part of the non-invasive blood oxygen module includes a system function module circuit, a communication interface circuit, and a JTAG interface circuit;

[0011] The non-invasive blood pressure module is used to monitor the blood pressure of the human body. The non-invasive blood pressure module includes an air circuit part, an analog part, an analog-to-digital conversion part, a central processing unit, and a digital part; the air circuit part is used to complete the inflation and deflation of the cuff; the analog part is used to complete the cuff pressure and pulse signal detection, and the analog part is composed of a pressure sensor, an instrument amplifier, a high-pass filter with an amplification function, and a low-pass filter; the analog-to-digital conversion part is used to convert the detected cuff pressure and cuff pressure pulsation wave into a digital signal; the digital part in the non-invasive blood pressure module is used to ensure the normal operation of the system function and the communication between the system and the inside and outside of the system. The digital part in the non-invasive blood pressure module includes a system function module circuit, a communication interface circuit, and a JTAG interface circuit;

[0012] The electrocardio-respiration and body temperature module is used to detect the electrocardio-respiration and body temperature conditions of a human body. The electrocardio-respiration and body temperature module includes an electrocardio-respiration monitoring part, a respiration monitoring part, and a body temperature monitoring part.

[0013] In a possible implementation, the digital power supply and the analog power supply in the power supply part of the non-invasive blood oxygen module are isolated by magnetic beads, and the analog ground plane and the digital ground plane are also isolated by magnetic beads.

[0014] In a possible implementation, an analog switch device is used in the non-invasive blood oxygen module signal separation circuit to divide the mixed signal into two paths, which are sampled separately, and the pulse wave signal is separated through a DC blocking capacitor.

[0015] In a possible implementation, the air circuit portion of the non-invasive blood pressure module includes an air pump, a solenoid valve, a cuff, and a pressure sensor. The air pump, cuff, pressure sensor, and solenoid valve are all connected to a multi-way connector through a catheter, and a one-way valve is installed on the catheter connected to the air pump.

[0016] In a possible implementation, the sensor selected for the simulation part of the non-invasive blood pressure module is the MPS3117A3 sensor.

[0017] In a possible implementation, the analog part of the non-invasive blood pressure module uses a differential amplifier circuit composed of an operational amplifier TLC2272ACD as a primary amplifier part.

[0018] In a possible implementation, the filter in the high-pass filter circuit of the analog part of the non-invasive blood pressure module is composed of a two-stage RC network, the two-stage RC network determines two cut-off frequencies, and the operational amplifier selected in the high-pass filter circuit is a high-precision operational amplifier LMC6482.

[0019] In a possible implementation, the overvoltage protection circuit of the ECG monitoring system of the ECG respiration and body temperature module is used to eliminate the influence of high-voltage signals on the ECG board, and the input part of the ECG monitoring system adopts an RC low-pass filter circuit to form a high-frequency filter for filtering out high-frequency signals existing in the space.

[0020] In a possible implementation, a buffer amplifier composed of an operational amplifier AD8226 is used in the ECG system of the ECG, respiration and body temperature module to ensure impedance matching of the signal during transmission and improve the input impedance of the circuit.

[0021] In a possible implementation, the ECG system of the ECG, respiration and body temperature module uses an ARM chip as a microprocessor for ECG signals, and downloads an ECG processing algorithm to an STM32 chip to process the ECG signals.

[0022] (III) Beneficial effects of the present invention:

[0023] The novel high-precision monitor disclosed by the present invention has the following beneficial effects:

[0024] 1. It can measure the blood oxygen, blood pressure, electrocardiogram, respiration and body temperature of the tester more accurately;

[0025] 2. The measurement operation is simple;

[0026] 3. Low production cost and high cost performance; BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a structural block diagram of a novel high-precision monitor system of the present invention;

[0028] Figure 2 This is the power supply principle of the non-invasive blood oxygen module of the present invention Figure 1 ;

[0029] Figure 3 This is the power supply principle of the non-invasive blood oxygen module of the present invention Figure 2 ;

[0030] Figure 4 This is the power supply principle of the non-invasive blood oxygen module of the present invention Figure 3 ;

[0031] Figure 5 This is a driving circuit diagram of a blood oxygen sensor of a non-invasive blood oxygen module of the present invention;

[0032] Figure 6 This is a signal amplification circuit diagram of the non-invasive blood oxygen module of the present invention;

[0033] Figure 7 This is a circuit diagram of the signal separation of the non-invasive blood oxygen module of the present invention;

[0034] Figure 8 This is the self-adaptive amplification circuit diagram of the non-invasive blood oxygen module of the present invention;

[0035] Fig. 9 This is a block diagram of the digital circuit design of the non-invasive blood oxygen module of the present invention;

[0036] Fig.10 This is a functional module schematic diagram of the non-invasive blood oxygen module system of the present invention;

[0037] Fig.11 This is the JTAG interface circuit diagram of the non-invasive blood oxygen module of the present invention;

[0038] Fig.12 This is the UART interface circuit diagram of the non-invasive blood oxygen module of the present invention;

[0039] Fig.13 It is the overall hardware block diagram of the non-invasive blood pressure module system of the present invention;

[0040] Fig.14 It is a circuit diagram of a constant current excitation source for a non-invasive blood pressure module of the present invention;

[0041] Fig.15 It is a non-invasive blood pressure module high-pass filter circuit diagram of the non-invasive blood pressure module of the present invention;

[0042] Fig.16 This is a block diagram of the digital circuit design of the non-invasive blood pressure module of the present invention;

[0043] Fig.17 This is a schematic diagram of the functional modules of the non-invasive blood pressure module system of the present invention;

[0044] Fig.18 It is the JTAG interface circuit diagram of the non-invasive blood pressure module of the present invention;

[0045] Fig.19 It is the UART interface circuit diagram of the non-invasive blood pressure module of the present invention;

[0046] Fig. 20 This is a circuit diagram of the pre-stage processing of the ECG signal of the non-invasive blood pressure module of the present invention;

[0047] Fig.21 It is a practical application circuit diagram of the non-invasive blood pressure module AD8226 of the present invention. DETAILED DESCRIPTION

[0048] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0049] like Figure 1-Figure 21 As shown, a multi-parameter high-precision monitor of the present invention includes: a non-invasive blood oxygen module, a non-invasive blood pressure module, and an electrocardiogram, respiration and body temperature module.

[0050] 1. The non-invasive blood oxygen module includes: power supply part, analog part and digital part.

[0051] In order to improve the measurement accuracy and obtain accurate measurement data, the power supply of the non-invasive blood oxygen module power supply should be a DC power supply with stable voltage, small ripple and no burrs. This power supply system obtains the required voltage to ensure the stable operation of the system by changing the voltage in two levels. The first level of voltage change uses the MAU203 DC-DC conversion power supply module in the voltage regulator to boost the 5V voltage to 9V, and then uses the LM1117 voltage regulator in the voltage regulator to linearly reduce the 9V voltage to 5V. The converted voltage powers the analog circuit. The main function of the DC-DC converter is to transform the input voltage and effectively output a fixed voltage, and to ensure the stability of the power supply of the entire circuit system by outputting a stable voltage. The second level of voltage change of the power supply part uses the voltage regulator SGM2036-3.3 and REF3025 to linearly reduce the voltage to 3.3V and 2.5V, of which 3.3V is used to power the microprocessor, and 2.5V is the bias voltage of the analog system part and the reference voltage for sampling of the analog-to-digital converter ADC in the microprocessor. The 3.3V digital power supply and analog power supply are isolated by magnetic beads, and the analog ground plane GND and digital ground plane DGND are also isolated by magnetic beads. Figure 2-Figure 4 shown.

[0052] The analog part of this non-invasive blood oxygen module is mainly composed of four parts: blood oxygen probe driving circuit, signal amplification circuit, signal separation circuit and AC small signal adaptive amplification circuit.

[0053] In order to reduce the complexity of the circuit hardware part, improve the accuracy of device control and the anti-interference ability of the measurement process, in the blood oxygen sensor driving circuit, the SGM3005XMS dual-channel analog switch integrated chip is used in combination with the corresponding software to realize the control of the light-emitting diode, so as to obtain the 240Hz light-emitting tube driving signal required for the measurement. This solution can accurately control the alternating light emission of the light-emitting diode of the blood oxygen sensor. Figure 5 shown.

[0054] The signal amplification circuit uses the precision low-noise CMOS rail-to-rail operational amplifier SGM8634 produced by Shengbang Microelectronics. SGM8634 is a low-noise, low-voltage and low-power operational amplifier that can convert the current signal obtained by the photodiode of the blood oxygen sensor into a voltage signal through the circuit, and then output it to the lower-level circuit. SGM8634 has extremely low input bias current (maximum 1pA) and current noise (12nV), and is very effective in high-sensitivity circuits.

[0055] Figure 6 This is the circuit diagram for signal amplification. In the figure, SPO2_PD + and SPO2_PD - are the current signals converted by the photodiode of the blood oxygen sensor, which are converted into voltage signals by the circuit and then output to the lower-level circuit. The AC voltage signal output by the operational amplifier circuit designed in this system is relatively weak, only a few millivolts.

[0056] The signal separation circuit uses analog switch devices to divide the mixed signal into two paths, which are sampled separately. The pulse wave signal is separated through a DC isolation capacitor.

[0057] According to the principle that oxygenated hemoglobin (HbO2) in the blood absorbs less red light with a wavelength of 660nm, but more infrared light with a wavelength of 940nm, while hemoglobin (Hb) absorbs the opposite, when red light and infrared light are irradiated on human tissues respectively, the blood oxygen content can be determined according to the light absorption of oxygenated hemoglobin (HbO2) and deoxyhemoglobin (Hb) in arterial blood. Therefore, in this circuit, it is necessary to separate the signal when the detection system is irradiated with red light and the signal when the infrared light is irradiated to calculate the value of blood oxygen to be detected. Figure 7 This is the signal separation circuit diagram. The analog switch device is used in the signal separation circuit to divide the mixed signal into two paths, and the two paths are sampled respectively. The pulse wave signal is separated through the DC isolation capacitor.

[0058] The pulse volume wave contains a DC component and an AC component. The DC component signal is stronger and the pulse wave fluctuation signal is weaker. The pulse wave fluctuation signal needs to be separated and amplified to a suitable range. In this AC small signal adaptive amplifier circuit, a digital potentiometer is used to achieve the goal of adaptive amplification. After the microprocessor ADC collects the pulse wave signal, it digitally filters the pulse wave signal and performs related operations. If the signal amplitude is small, it is necessary to increase the amplification factor. If the signal amplitude is large, it is necessary to reduce the amplification factor. After multiple amplifications or reductions, the signal amplitude is stabilized in a relatively suitable range. In this circuit, the VDAC0 bias voltage is crucial, and its parameters are directly related to the regulation of the pulse wave signal and the quality of the system performance. The circuit design diagram of the adaptive amplifier circuit is shown in FIG. Figure 8 shown.

[0059] The digital part includes system function module circuit, communication interface circuit, and JTAG interface circuit. The digital part design block diagram is as follows Fig. 9 shown.

[0060] The system function module circuit includes: clock circuit, reset circuit, JTAG download circuit and decoupling circuit. The clock circuit generates an oscillation circuit that moves as accurately as a clock so that any work can be carried out in chronological order. The reset circuit can restore the circuit to the starting state, just like the function of the reset button on a calculator, so as to return to the original state and recalculate. The decoupling circuit is to ensure the full ADC and DAC performance of the STM32F103VCT6. Capacitors are added between each pair of 3.3V digital power and digital ground pins of the chip for decoupling, and decoupling is added between the 3.3V analog power and analog ground pins. These small capacitors should be as close to the power pins of the device as possible, and the other end should be directly connected to the ground plane of the device. The schematic diagram of the system function module is as follows: Fig.10 shown.

[0061] The system uses a JTAG emulator, which is connected to the PC via the USB port through the emulator. The schematic diagram of the JTAG interface is as follows: Fig.11 shown.

[0062] The UART interface circuit needs to send the processed data to the host computer. Since the environment in which the non-invasive blood oxygen module is used is very complex, in order to ensure the reliability of serial port data transmission, a serial port isolation strategy is adopted in the circuit design. Fig.12 shown.

[0063] Blood oxygen saturation (SaO2) is the amount of oxygen in the blood The capacity of (HbO2) accounts for the percentage of the total capacity of hemoglobin (Hb, hemoglobin), that is, the concentration of blood oxygen in the blood, which is an important physiological parameter of respiratory circulation. The non-invasive blood oxygen module of the present invention includes: a power supply part, an analog part, and a digital part.

[0064] The power supply part must take into account both personal safety and technical parameters. The noise of the reverse bias voltage of the photodiode is one of the main sources of noise, which requires the stability and "purity" of the power supply. In order to improve the measurement accuracy and obtain accurate measurement data, the power supply of the non-invasive blood oxygen module power supply part should choose a DC power supply with stable voltage, small ripple and no burrs. This power supply system uses an external 5V DC power supply, and obtains the required voltage to ensure stable operation of the system by changing the voltage in two levels. The 3.3V digital power supply and the analog power supply are isolated by magnetic beads, and the analog ground plane GND and the digital ground plane DGND are also isolated by magnetic beads.

[0065] The blood oxygen sensor driving circuit uses the SGM3005XMS dual-channel analog switch integrated chip combined with corresponding software to realize the control of the light-emitting diode. This solution can accurately control the alternating light emission of the blood oxygen sensor light-emitting diode. The blood sample information measured by the blood oxygen sensor is transmitted to the signal amplification circuit through the blood oxygen sensor driving circuit.

[0066] The signal amplification circuit uses the precision low-noise CMOS rail-to-rail operational amplifier SGM8634 produced by Shengbang Microelectronics. SGM8634 can convert the current signal obtained by the photodiode of the blood oxygen sensor into a voltage signal through the circuit, and then output it to the next-level signal separation circuit.

[0067] The signal separation circuit uses analog switch devices to divide the mixed signal into two paths, which are sampled separately. The pulse wave signal is separated by a DC isolation capacitor and then transmitted to the adaptive amplifier circuit.

[0068] When the microprocessor ADC receives the pulse wave signal, it digitally filters the pulse wave signal and performs related operations. If the signal amplitude is small, the amplification factor needs to be increased. If the signal amplitude is large, the amplification factor needs to be reduced. After multiple amplifications or reductions, the signal amplitude is stabilized in a relatively appropriate range. In this adaptive amplifier circuit, the VDAC0 bias voltage is crucial, and its parameters are directly related to the regulation of the pulse wave signal and the quality of the system performance. The obtained signal is processed by the digital part and displayed on the display screen.

[0069] This system uses a 12-bit precision ADC, and the circuit board uses a modular wiring method. When wiring, the traces should be as short as possible, the vias should be as small as possible, the isolation beads should be attached to the back of the chip, and the filter capacitor should be as close to the power supply as possible to reduce interference and noise. In addition, the power supply part, analog part, and digital part components should be placed in different areas, and the power supply and ground of the analog and digital parts should be strictly separated by magnetic beads to reduce mutual interference between circuits. The circuit board diagram is as follows Figure 1 shown.

[0070] 2. The non-invasive blood pressure module includes: gas circuit part, analog part, analog-to-digital conversion part, central processing unit, and digital part.

[0071] The air circuit is composed of air pump, solenoid valve, cuff, pressure sensor and other components, which mainly complete the inflation and deflation of the cuff. Among them, the air pump is driven by a DC motor, there are two solenoid valves, the step deflation valve responds quickly and can achieve accurate deflation, and the air release valve can achieve large-flow deflation after measurement is completed or in the event of a fault. The air pump, cuff, pressure sensor, and solenoid valve are all connected to the multi-way connector through a catheter. The catheter connected to the air pump is equipped with a one-way valve to minimize the leakage of the system.

[0072] The analog part mainly completes the cuff pressure and pulse signal detection, and is composed of a pressure sensor, an instrument amplifier, a high-pass filter with amplification function, and a low-pass filter. One pressure sensor is used to monitor the cuff pressure to ensure that its pressure value is within a safe range, and the other pressure sensor is used to sense the mixed signal of the cuff pressure and the pulse wave. The instrument amplifier amplifies the differential signal output by the pressure sensor and outputs a mixed signal of the cuff pressure and the pulse wave signal. The high-pass filter with amplification function filters out the cuff pressure that is close to DC and amplifies the pulse wave signal. The low-pass filter is used to filter out high-frequency noise that is higher than the pulse wave frequency component, and the output is sent to the A / D converter as a pulse wave signal.

[0073] The sensor used in this simulation part is the MPS3117A3 series sensor, which has the following advantages: 1. It has compensation and correction in a wide temperature range, and temperature compensation of 0℃~60℃; 2. Dual in-line package, DIP package that can be used for PCB installation, can be installed on the printed circuit board like ordinary devices; 3. 50mV full range output; 4. ±0.1% accuracy; 5. Interchangeability; 6. Compatible with various media; 7. Absolute pressure and standard pressure are optional; 8. Built-in high-precision current setting resistor, etc. Fig.14 The constant current excitation source provides a circuit diagram as shown. The input excitation source of MPS3117A3 is a mA-level constant current. Fig.14 The circuit shown realizes V / I conversion and provides a constant current excitation source. The output of the sensor MPS3117A3 is a 60-90 mV differential signal. Since the weak effective signal also contains common-mode interference such as power frequency, static electricity and electromagnetic coupling, the primary amplifier circuit should have a high common-mode rejection ratio, high gain, low noise and high input impedance in view of the particularity of such biological signals.

[0074] The operational amplifier TLC2272ACD is composed of three amplifiers and a resistor network that has been corrected by laser resistance trimming. Only one external resistor is needed to achieve accurate gain setting from 1 to tens of thousands times, reducing the data acquisition error caused by gain-related errors. The differential amplifier circuit composed of the operational amplifier TLC2272ACD is used as the primary amplifier. The TLC2272ACD has the characteristics of high input impedance, low output impedance, strong anti-common mode interference ability, low temperature drift, low offset voltage and high stable gain. The operational amplifier TLC2272ACD is widely used as a preamplifier in the weak signal detection system.

[0075] The analog part of the present invention adopts a two-stage high-pass filter amplifier to separate the pulse wave signal from the cuff pressure signal before the pulse wave signal enters the post-amplification stage, so as to extract a relatively pure pulse wave signal so that it can truly reflect the changes in the pulse to the greatest extent. Fig.15A two-stage filter circuit with both amplification and high-pass filtering is given. The operational amplifier selected is the high-precision operational amplifier LMC6482, which has a high common-mode input range, common-mode rejection ratio CMRR=82dB, and an extremely wide power supply range, good 3V, 5V and 15V performance, and ultra-low input : 20fA, etc. The filter in the high-pass filter circuit of the present invention is composed of a two-stage RC network, which determines two cut-off frequencies. The two-stage RC network should be carefully selected to ensure that the pulsating oscillation signal will not be distorted or lost.

[0076] The analog-to-digital conversion part is composed of multiple A / D converters, and the content converted by the A / D converters is the cuff pressure and the cuff pressure pulsation wave. In the present invention, the A / D converter is designed as an on-chip peripheral integrated in a single-chip microcomputer.

[0077] The function of the central processing unit is to receive system parameter settings given by the PC through the serial port, send control commands to various parts of the system, transmit measurement data to the PC, and perform calculations through various algorithms during the monitoring process. The measurement data transmitted to the PC include: systolic blood pressure, diastolic blood pressure, mean blood pressure, heart rate and pulse pressure waveform data.

[0078] The digital part includes system function module circuit, communication interface circuit, and JTAG interface circuit. The digital part circuit design block diagram is as follows Fig.16 shown.

[0079] The system function module circuit includes: clock circuit, reset circuit, JTAG download circuit and decoupling circuit. The clock circuit generates an oscillation circuit that moves as accurately as a clock so that any work can be carried out in chronological order. The reset circuit can restore the circuit to the starting state, just like the function of the reset button on a calculator, so as to return to the original state and recalculate. The decoupling circuit is to ensure the full ADC and DAC performance of the STM32F101V8T6. Capacitors are added between each pair of 3.3V digital power and digital ground pins of the chip for decoupling, and decoupling is added between the 3.3V analog power and analog ground pins. These small capacitors should be as close to the power pins of the device as possible, and the other end should be directly connected to the ground plane of the device. The schematic diagram of the system function module is as follows: Fig.17 shown.

[0080] The system uses a JTAG emulator, which is connected to the PC via the USB port through the emulator. The schematic diagram of the JTAG interface is as follows: Fig.18 shown.

[0081] The UART interface circuit needs to send the processed data to the host computer. Since the environment in which the non-invasive blood oxygen module is used is very complex, in order to ensure the reliability of serial port data transmission, a serial port isolation strategy is adopted in the circuit design. Fig.19 shown.

[0082] When measuring blood pressure, the gas circuit part completes the inflation and deflation of the cuff, and the analog part completes the detection of the cuff pressure and pulse signal. Among them, a pressure sensor in the analog part is used to monitor the cuff pressure to ensure that its pressure value is within a safe range, and the other pressure sensor is used to sense the mixed signal of the cuff pressure and the pulse wave. The pressure sensor that senses the mixed signal of the cuff pressure and the pulse wave transmits the measured signal to the instrument amplifier, which amplifies the differential signal output by this pressure sensor and outputs a mixed signal of the cuff pressure and the pulse wave signal. Then the high-pass filter with amplification function filters out the cuff pressure that is close to DC and amplifies the pulse wave signal. Then the low-pass filter filters out the high-frequency noise higher than the pulse wave frequency component, and the output is sent to the A / D converter as a pulse wave signal. The obtained signal is processed by the digital part and displayed on a display screen or other means.

[0083] 3. The ECG, respiration and body temperature module includes: ECG monitoring part, respiration monitoring part and body temperature monitoring part.

[0084] ECG monitoring hardware is mainly composed of ECG signal input, amplification, processing and output. ECG signals are relatively weak low-frequency signals and are often accompanied by many interference signals. These interference signals mainly come from myoelectric interference, baseline drift, 50Hz / 60Hz power frequency interference, etc., which are generated by muscle movement. The existence of interference signals makes it difficult to extract ECG signals. In order to obtain a relatively clean ECG signal, the front-end amplifier circuit of ECG detection should have the characteristics of low noise, high input impedance, low temperature drift and appropriate bandwidth.

[0085] The ECG signal input part transmits the human body's ECG signals to the ECG analysis system through the leads via hardware circuit modules such as electrodes, lead wires, overvoltage protection circuits and high-frequency filters.

[0086] The main function of the lead wire is to transmit the ECG signal obtained from the electrode to the input of the operational amplifier. A twelve-lead ECG requires eight channels and ten lead wires, of which one lead wire corresponds to each of the four limbs of the human body and six lead wires correspond to the chest cavity. In the ECG monitoring system of the present invention, the lead for processing the ECG signal is switched by software switching. In the ECG signal analysis, in the absence of manual switching, the system will analyze the lead with the strongest signal, thus avoiding the inaccuracy of the ECG signal analysis result when the signal of a single lead is weak.

[0087] When the ECG monitoring system is working, some high-voltage signals often penetrate into the system through the electrodes and wires. For example, when a patient under ECG monitoring is undergoing defibrillation treatment, the defibrillation pulses generated by the defibrillator will enter the ECG board through the lead wires. Therefore, the present invention eliminates the influence of the high-voltage signal on the ECG board through an overvoltage protection circuit.

[0088] A high-frequency filter composed of an RC low-pass filter circuit is used in the input part to filter out the high-frequency signal in the space, thereby reducing the impact of high-frequency interference on the ECG signal. Fig.19 shown.

[0089] When the ECG signal of the human body is transmitted to the input end of the circuit, it passes through the internal resistance of the human body, the resistance of the electrode sheet in contact with the skin, and the lead wire. In this process, the signal will be attenuated and distorted due to interference from various factors. Therefore, a buffer amplifier is used in the processing of the ECG signal to ensure the impedance matching of the signal during the transmission process and to increase the input impedance of the circuit. The buffer amplifier is generally implemented as a voltage follower composed of an operational amplifier. The present invention selects the AD8226 operational amplifier in the design of the ECG detection circuit to cope with the situation where the signal is very weak and the source impedance of the signal is extremely high during the ECG monitoring process. The low power consumption and low voltage noise of the operational amplifier AD8226 can make the monitoring circuit have better performance. The actual application circuit of AD8226 is as follows: Fig. 20 shown.

[0090] The function of the amplifier part in the ECG monitoring part is to amplify the weak ECG signal to a level that can be observed and analyzed, and to process some interference signals to obtain an ECG signal with relatively high signal quality. The amplifier part adopts a three-stage amplification technical solution: 1. The preamplifier circuit performs the first amplification of the ECG signal and filters the ECG signal; 2. The intermediate amplifier circuit amplifies the signal processed by the preamplifier; 3. The post-amplifier circuit performs the final amplification of the ECG signal. In the post-amplifier circuit, the polarization voltage needs to be filtered out and then the analog-to-digital conversion is performed. The creative design of the dedicated thin film capacitor external circuit eliminates the influence of the polarization voltage on the ECG signal, so that the sampling can obtain a high-quality ECG signal. Its detailed design is as follows: Fig.21 shown.

[0091] The processing part of the ECG monitoring uses the high-performance ARM chip launched by STMicroelectronics as the microprocessor of the ECG signal, and the ECG processing algorithm is downloaded to the STM32 chip to process the ECG signal. The STM32 chip has the advantages of low price, excellent performance, and simple programming.

[0092] The ECG board uses two power supply methods: alternating current and direct current.

[0093] When measuring ECG signals, the ECG signal input part transmits the ECG signals of the human body to the ECG analysis system through the electrodes, lead wires, overvoltage protection circuits, high-frequency filters and other hardware circuit modules. After the lead wire obtains the ECG signals through the electrodes, it transmits the obtained ECG signals to the input end of the operational amplifier. The function of the amplification part in the ECG monitoring part is to amplify the weak ECG signals to a level that can be observed and analyzed, and to process some interference signals to obtain ECG signals with relatively high signal quality. The obtained signal is processed by the digital part and displayed on the display screen.

[0094] The respiratory monitoring hardware circuit design of the present invention mainly adopts the principle of the chest impedance method. In the process of using the impedance method to measure, a relatively convenient two-electrode method is adopted, where electrode one is placed on the right chest of the subject, and electrode two is placed on the left abdomen of the subject. When the subject breathes calmly, the chest impedance will change. After collecting the signal, the interference of the low-frequency signal is greatly reduced by rectifying, filtering and amplifying the signal.

[0095] When monitoring breathing conditions, electrode 1 is placed on the right chest of the subject, and electrode 2 is placed on the left abdomen of the subject. When the subject breathes calmly, the chest impedance will change. After collecting the signal, the interference of low-frequency signals is greatly reduced by rectifying, filtering, and amplifying the signal.

[0096] The temperature monitoring hardware of the present invention mainly adopts the bridge balance principle to monitor tiny temperature signals, adopts a correction and compensation method based on an operational amplifier circuit, combined with a high-precision linear interpolation "soft correction" method, effectively solves the nonlinear error problem of thermistor temperature measurement circuit, and improves measurement accuracy.

[0097] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A new type of high-precision monitor, characterized in that: include: Non-invasive blood oxygen module, non-invasive blood pressure module, ECG, respiration and body temperature module; The non-invasive blood oxygen module is used to monitor the blood oxygen saturation in human blood. The non-invasive blood oxygen module includes: a power supply part, an analog part, and a digital part; The power supply part in the non-invasive blood oxygen module is used to supply power to the non-invasive blood oxygen module; The analog part of the non-invasive blood oxygen module is used to monitor the human pulse wave signal and adjust the pulse wave signal amplitude to the required range. The analog part of the non-invasive blood oxygen module is mainly composed of a blood oxygen probe driving circuit, a signal amplification circuit, a signal separation circuit and an adaptive amplification circuit; the blood oxygen probe driving circuit is used to control the alternating light emission of the blood oxygen probe light emitting diode. The blood oxygen probe driving circuit uses the SGM3005XMS dual-channel analog switch integrated chip combined with software to realize the control of the light emitting diode; the signal amplification circuit is used to convert the current signal obtained by the photosensitive diode of the blood oxygen probe into a voltage signal through the circuit, and then output it to the lower circuit. The operational amplifier SGM8634 is used in the signal amplification circuit to convert the current signal obtained by the photosensitive diode of the blood oxygen probe into a voltage signal; the adaptive amplification circuit is used to adjust the pulse wave signal amplitude to the required range, and the VDAC0 bias voltage is set in the adaptive amplification circuit; the signal separation circuit separates the signal when the red light is irradiated and the signal when the infrared light is irradiated to calculate the value of the blood oxygen to be detected; The digital part of the non-invasive blood oxygen module is used to ensure the normal operation of the system function and the communication between the system and the inside and outside of the system. The digital part of the non-invasive blood oxygen module includes a system function module circuit, a communication interface circuit, and a JTAG interface circuit; The non-invasive blood pressure module is used to monitor the blood pressure of the human body. The non-invasive blood pressure module includes an air circuit part, an analog part, an analog-to-digital conversion part, a central processing unit, and a digital part; the air circuit part is used to complete the inflation and deflation of the cuff; the analog part is used to complete the cuff pressure and pulse signal detection, and the analog part is composed of a pressure sensor, an instrument amplifier, a high-pass filter with an amplification function, and a low-pass filter; the analog-to-digital conversion part is used to convert the detected cuff pressure and cuff pressure pulsation wave into a digital signal; the digital part in the non-invasive blood pressure module is used to ensure the normal operation of the system function and the communication between the system and the inside and outside of the system. The digital part in the non-invasive blood pressure module includes a system function module circuit, a communication interface circuit, and a JTAG interface circuit; The electrocardio-respiration and body temperature module is used to detect the electrocardio-respiration and body temperature conditions of a human body. The electrocardio-respiration and body temperature module includes an electrocardio-respiration monitoring part, a respiration monitoring part, and a body temperature monitoring part.

2. A novel high-precision monitor as claimed in claim 1, characterized in that: The digital power supply and the analog power supply in the power supply part of the non-invasive blood oxygen module are isolated by magnetic beads, and the analog ground plane and the digital ground plane are also isolated by magnetic beads.

3. A novel high-precision monitor as claimed in claim 1, characterized in that: The non-invasive blood oxygen module signal separation circuit uses an analog switch device to divide the mixed signal into two paths, which are sampled respectively, and the pulse wave signal is separated through a DC blocking capacitor.

4. A novel high-precision monitor as claimed in claim 1, characterized in that: The air circuit part of the non-invasive blood pressure module includes an air pump, a solenoid valve, a cuff, and a pressure sensor. The air pump, cuff, pressure sensor, and solenoid valve are all connected to a multi-way connector through a catheter, and a one-way valve is installed on the catheter connected to the air pump.

5. A novel high-precision monitor as claimed in claim 1, characterized in that: The sensor selected for the simulation part of the non-invasive blood pressure module is the MPS3117A3 sensor.

6. A novel high-precision monitor as claimed in claim 1, characterized in that: The analog part of the non-invasive blood pressure module adopts a differential amplifier circuit composed of an operational amplifier TLC2272ACD as a primary amplifier part.

7. A novel high-precision monitor as claimed in claim 1, characterized in that: The filter in the high-pass filter circuit of the analog part of the non-invasive blood pressure module is composed of a two-stage RC network, and the two-stage RC network determines two cut-off frequencies. The operational amplifier selected in the high-pass filter circuit is the high-precision operational amplifier LMC6482.

8. A novel high-precision monitor as claimed in claim 1, characterized in that: The overvoltage protection circuit of the ECG monitoring system of the ECG respiration and body temperature module is used to eliminate the influence of high-voltage signals on the ECG board. The input part of the ECG monitoring system adopts an RC low-pass filter circuit to form a high-frequency filter to filter out high-frequency signals in the space.

9. A novel high-precision monitor as claimed in claim 1, characterized in that: The ECG system of the ECG, respiration and body temperature module adopts a buffer amplifier composed of an operational amplifier AD8226 to ensure impedance matching of the signal during transmission and improve the input impedance of the circuit.

10. A novel high-precision monitor as claimed in claim 1, characterized in that: The ECG system of the ECG, respiration and body temperature module adopts an ARM chip as a microprocessor of the ECG signal, and downloads the ECG processing algorithm into the STM32 chip to process the ECG signal.

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