QCM sensor blood coagulation detection method and system based on amplitude detection

Abstract

A QCM sensor blood coagulation detection method and system based on amplitude detection relates to the sensor technology and blood coagulation monitoring field, and comprises the following steps: a DDS frequency sweep source outputs a frequency sweep signal; when blood is solidified on the surface of the quartz crystal, the resonant frequency of the quartz crystal is changed; the QCM sensor monitors a sweep frequency signal and reflects the amplitude of the signal according to the change of the resonant frequency; the DDS sweep frequency source gradually adjusts the frequency, and the QCM sensor monitors the amplitude change of the signal; the amplitude discrimination module detects the signal amplitude in real time and feeds back the signal to the single-chip microcomputer; the single-chip microcomputer controls sweep frequency parameters so as to control the sweep frequency process of the DDS sweep frequency source, processes received signals and outputs measurement results, and blood coagulation function monitoring is completed. According to the invention, the amplitude fluctuation in the blood coagulation process is monitored in real time through the relationship between the load mass and the signal amplitude change, so that the resonant frequency change curve of the quartz crystal under different blood coagulation functions is reflected, the detection precision and stability are improved, and the method has a wider application prospect.

Description

Technical Field

[0001] The present invention relates to the technical fields of sensor technology and blood coagulation monitoring technology, and particularly relates to a QCM sensor blood coagulation detection method and system based on amplitude detection. Background Art

[0002] Blood coagulation function monitoring is an indispensable part of clinical diagnosis and treatment, and is particularly crucial in patients undergoing surgery, trauma treatment, and those using anticoagulant drugs for a long time. Traditional blood coagulation function detection methods, such as prothrombin time (PT) and activated partial thromboplastin time (APTT), usually require the use of complex laboratory equipment and blood sampling for chemical reagent reactions, so there are problems such as complex operation, long detection cycle, and strong patient dependence.

[0003] With the development of medical technology, the demand for portable and real-time monitoring systems is increasing day by day, especially in patients during the clinical recovery period or home patients, who need a device that is easy to carry and can provide real-time feedback of detection results. Currently, there is no highly efficient, accurate, and convenient blood coagulation function detection system on the market. Therefore, there is an urgent need for a new detection method that can improve the detection accuracy and facilitate self-monitoring and management by patients.

[0004] The quartz crystal microbalance (QCM), as a high-precision sensor, is widely used in the fields of gas, liquid, and biological analysis. The core principle of QCM technology is to utilize the resonance characteristics of quartz crystals at a specific frequency and detect minute mass changes by measuring the change in resonance frequency. According to the Sauerbrey formula, there is a linear relationship between the resonance frequency of the quartz crystal and the mass attached to the surface. Therefore, QCM can measure the change in surface mass very precisely.

[0005] QCM sensors have the advantages of high sensitivity, non-contact detection, and fast response, and are particularly suitable for the detection of trace substances. In biosensing applications, QCM can monitor the interaction between biomolecules and biological reactions, such as the binding of proteins, antibodies, or DNA. In the detection of blood coagulation function, QCM can be used to monitor the blood coagulation process in real time, especially the changes at the particle and molecular levels during blood coagulation.

[0006] However, most traditional QCM detection methods rely on phase detection, which has high requirements for system accuracy and hardware, and is easily affected by factors such as noise and environmental changes during the detection process. Therefore, there is currently a lack of a QCM sensor method based on amplitude change detection in the prior art, which can effectively reduce the requirements for system accuracy and hardware and provide a more stable and convenient blood coagulation function monitoring method. Summary of the Invention

[0007] To solve the problems existing in the prior art, the present invention provides a QCM sensor blood coagulation detection method and system based on amplitude detection. By combining the QCM sensor with the voltage amplitude ratio detection technology, the present invention is used for the detection of the blood coagulation function of patients.

[0008] Different from the traditional QCM sensor that relies on high-precision phase detection method, the present invention can significantly reduce the hardware requirements for the instrument while ensuring high detection accuracy by designing a simple and effective voltage amplitude ratio detection system. This innovative method of the present invention solves the dependence on complex circuits and high-cost equipment in the prior art, greatly reduces the cost of the overall system and improves the system popularity, and is particularly suitable for the daily monitoring of patients in the clinical recovery period.

[0009] The technical solutions adopted by the present invention to solve the technical problems are as follows:

[0010] A QCM sensor blood coagulation detection method based on amplitude detection provided by the present invention includes the following steps:

[0011] (1) Start the DDS frequency sweep source and the signal conditioning circuit, and use the signal conditioning circuit to control the DDS frequency sweep source to output a stable frequency sweep signal and transmit it to the QCM sensor;

[0012] (2) Drop blood on the surface of the quartz crystal. When the blood coagulates on the surface of the quartz crystal, it will cause the resonance frequency of the quartz crystal to change; the QCM sensor monitors the frequency sweep signal and reacts the signal amplitude according to the change of the resonance frequency;

[0013] (3) The DDS frequency sweep source gradually adjusts the frequency of the frequency sweep signal, and the QCM sensor monitors the change of the signal amplitude in real time;

[0014] (4) The amplitude discrimination module detects the signal amplitude in real time, and feeds back the signal to the single-chip microcomputer through the signal acquisition module;

[0015] (5) Use the single-chip microcomputer to control the frequency sweep parameters to control the frequency sweep process of the DDS frequency sweep source; at the same time, the single-chip microcomputer uses the Kalman filtering algorithm to optimize the received signal, and outputs the measurement result to the human-computer interaction module for display and the data storage module for storage;

[0016] (7) The user can adjust the system parameters through the human-computer interaction module, and the single-chip microcomputer gives feedback and controls the frequency sweep process;

[0017] (8) Finally, the measurement result is displayed and output through the upper computer to complete the blood coagulation function monitoring.

[0018] Furthermore, the phenomenon that the increase in the surface mass density of the quartz crystal is proportional to the decrease in its resonance frequency is described by the Sauerbrey equation:

[0019]

[0020] Among them, is defined as the mass sensitivity of the quartz crystal, represents the square of the fundamental frequency (resonant frequency) of the quartz crystal, ρ q represents the density of the quartz crystal, v q represents the acoustic wave propagation speed (shear mode wave speed) of the quartz crystal; by measuring the change in the resonant frequency, the change in the mass on the surface of the quartz crystal during the blood coagulation process is reflected.

[0021] Furthermore, the impedance formula of the equivalent circuit of the quartz crystal is:

[0022]

[0023] In the formula, Z represents the total impedance in the circuit, R represents the resistance in the circuit, j represents the imaginary unit, ω represents the angular frequency of the AC signal, L represents the inductance value in the circuit, and C represents the capacitance value in the circuit.

[0024] Furthermore, when the equivalent circuit of the quartz crystal is at the resonant frequency, the inductance part and the capacitance part of the equivalent circuit cancel each other out, and the impedance of the quartz crystal decreases sharply, resulting in the voltage across the quartz crystal being much greater than the voltage across the DDS frequency sweep source. This characteristic is used to accurately measure the resonant frequency.

[0025] Furthermore, the signal conditioning circuit uses a gain control and a digital filtering algorithm to optimize the output signal; the gain control is used to automatically adjust the signal amplitude to ensure that it is within the optimal working range; the digital filtering algorithm is used to suppress the noise and spurious components in the frequency signal and output a stable frequency sweep signal.

[0026] Furthermore, in step (4), an adaptive variable step size control algorithm is adopted, and by real-time collecting the amplitude information and feeding it back to the single-chip microcomputer, the frequency register in the DDS frequency sweep source is accurately adjusted.

[0027] Furthermore, a logarithmic amplifier is used inside the amplitude discrimination module to convert the input signal amplitude into a voltage signal in logarithmic form.

[0028] A QCM sensor blood coagulation detection system based on amplitude detection provided by the present invention includes:

[0029] a cloud display module, a data storage module, a human-computer interaction module, a single-chip microcomputer, a power supply module, a DDS frequency sweep source, a signal conditioning circuit, a QCM sensor, an amplitude discrimination module, and a signal acquisition module;

[0030] Cloud display module, which is used to upload the collected experimental data to the cloud display module in real time for users to view the change curve of the quartz crystal resonance frequency through mobile phones, computers or other terminal devices;

[0031] Data storage module, which is used to locally store the collected resonance frequency data for the cloud display module to use; and for subsequent analysis and comparison of experimental results;

[0032] Human-machine interaction module, which is used to manually adjust and control system parameters to adapt to quartz crystals with different resonance frequencies; and to receive the data fed back by the single-chip microcomputer;

[0033] Single-chip microcomputer, which is used to control the frequency sweep parameters to control the frequency sweep process of the DDS frequency sweep source; and to optimize the signal sent by the signal acquisition module using the Kalman filtering algorithm; and to feed back data to the human-machine interaction module;

[0034] Power supply module, which is used to supply power to the single-chip microcomputer, DDS frequency sweep source, QCM sensor, amplitude discrimination module and signal acquisition module;

[0035] DDS frequency sweep source, which is used to output a stable frequency sweep signal and to gradually adjust the frequency of the frequency sweep signal;

[0036] Signal conditioning circuit, which is used to amplify, filter and other processes the signal output by the QCM sensor to improve the signal quality and ensure that the subsequent signal acquisition module can accurately obtain the resonance frequency and amplitude information;

[0037] QCM sensor, which is used to monitor the frequency sweep signal and react the signal amplitude according to the change of the resonance frequency, and to monitor the change of the signal amplitude in real time;

[0038] Amplitude discrimination module, which internally uses a logarithmic amplifier to detect the response of the resonance frequency and to detect the signal amplitude in real time;

[0039] Signal acquisition module, which is used to collect the voltage signal of the amplitude discrimination module in real time and feed the signal back to the single-chip microcomputer.

[0040] Furthermore, the human-machine interaction module includes: a host computer display module, an LCD screen display module, a button control module and a touch screen control module; the host computer display module is used to display the change curve of the resonance frequency in the mobile terminal, the LCD screen display module is used to display the change curve of the resonance frequency on this system, the button control module is used to adjust the parameters of the frequency sweep module, and the touch screen control module is used to switch the frequency sweep mode and reset the system.

[0041] Further, a frequency register, a phase accumulator, a waveform memory, and a digital-to-analog converter are provided in the DDS frequency sweep source; the frequency register is used to store the frequency set value of the frequency sweep signal and control the output frequency of the DDS frequency sweep source; the phase accumulator is used to generate phase information and accumulate phase values according to the frequency control word (FTW, Frequency Tuning Word); the waveform memory is used to store standard waveform data (such as sine wave, square wave, or triangular wave); the digital-to-analog converter is used to convert the digital signal (standard waveform data from the waveform memory) generated by the DDS module into an analog signal.

[0042] The beneficial effects of the present invention are:

[0043] By establishing the relationship between the load mass and the signal amplitude change, the present invention proposes a method and system for detecting blood coagulation of a QCM sensor based on amplitude detection. When the blood coagulation state changes, the present invention monitors the amplitude change amount of the QCM sensor signal, and then reflects the resonance frequency change of the quartz crystal under different blood coagulation functions.

[0044] Based on the relationship between the load mass and the signal amplitude change, the present invention monitors the amplitude fluctuation during the blood coagulation process in real time, so as to reflect the resonance frequency change curve of the quartz crystal under different blood coagulation functions. The system adopts a high-speed DDS frequency sweep source and combines an accurate signal conditioning circuit to ensure the stable output of the signal amplitude and the accuracy of frequency acquisition. To achieve more precise control, the present invention introduces an adaptive variable step size control algorithm, which collects and feedbacks the amplitude information in real time, and dynamically adjusts the frequency register in the DDS frequency sweep source, thereby optimizing the frequency response. A high-precision amplitude discrimination module is designed, and advanced circuit optimization technology is adopted to overcome the problems of signal noise and amplitude distortion, ensuring the high reliability of the signal amplitude change. To further improve the accuracy and stability of the data, the system adjusts the output resonance frequency data in real time through the Kalman filter algorithm, significantly improving the resistance of the system to environmental interference and ensuring the high accuracy and high reliability of blood coagulation function monitoring. The present invention not only breaks through the limitations of traditional methods, but also has a broader application prospect, and is particularly suitable for clinical health monitoring and remote medical systems. Description of the Drawings

[0045] Figure 1 is a schematic diagram of the structural composition of a blood coagulation detection system for a QCM sensor based on amplitude detection provided by the present invention.

[0046] Figure 2 is a flowchart of a method for detecting blood coagulation of a QCM sensor based on amplitude detection provided by the present invention.

[0047] Figure 3 is the amplitude difference of the resonance frequency.

[0048] Figure 4 It is the effect diagram of Kalman filtering.

[0049] Figure 5 It is the change diagram of the resonant frequency curve of the blood coagulation process. Specific implementation manners

[0050] The present invention will be further described in detail below with reference to the accompanying drawings.

[0051] In a first aspect, the present invention provides a QCM sensor blood coagulation detection system based on amplitude detection.

[0052] See Figure 1 For illustration, a QCM sensor blood coagulation detection system based on amplitude detection provided by the present invention specifically includes the following modules:

[0053] A cloud display module, a data storage module, a human-computer interaction module, a single-chip microcomputer, a power supply module, a signal source, a QCM sensor, an amplitude discrimination module, and a signal acquisition module; wherein, the signal source is mainly composed of a DDS frequency sweep source and a signal conditioning circuit; their connection relationship is: the cloud display module is connected to the data storage module, and the data storage module is respectively connected to the human-computer interaction module and the single-chip microcomputer; the power supply module is respectively connected to the single-chip microcomputer, the DDS frequency sweep source, the QCM sensor, the amplitude discrimination module, and the signal acquisition module; the single-chip microcomputer is connected to the DDS frequency sweep source, the DDS frequency sweep source is connected to the QCM sensor, the QCM sensor is connected to the amplitude discrimination module, the amplitude discrimination module is connected to the signal acquisition module, and the signal acquisition module is connected to the single-chip microcomputer.

[0054] In the present invention, the functions and roles of each module are as follows:

[0055] The cloud display module is mainly used to upload the collected experimental data to the cloud display module in real time for the user to view the change curve of the quartz crystal resonant frequency through a mobile phone, a computer or other terminal devices.

[0056] The data storage module is mainly used to locally store the collected resonant frequency data for use by the cloud display module; and for subsequent analysis and comparison of experimental results.

[0057] The human-computer interaction module is mainly used to manually adjust and control system parameters to adapt to quartz crystals with different resonant frequencies; and to receive the data fed back by the single-chip microcomputer.

[0058] In the present invention, the human-machine interaction module mainly includes: a host computer display module, an LCD screen display module, a button control module, and a touch screen control module; among them, the host computer display module is mainly used to display the resonance frequency change curve in the mobile terminal, the LCD screen display module is mainly used to display the resonance frequency change curve on this system, the button control module is mainly used to adjust the parameters of the frequency sweeping module, and the touch screen control module is mainly used to switch the frequency sweeping mode and reset the system.

[0059] The single-chip microcomputer is mainly used to control the frequency sweeping parameters to control the frequency sweeping process of the DDS frequency sweeping source; and is used to optimize the signals (i.e., frequency sweeping results) sent by the signal acquisition module by using the Kalman filtering algorithm; and is used to feedback data to the human-machine interaction module.

[0060] The power supply module is mainly used to supply power to the single-chip microcomputer, the DDS frequency sweeping source, the QCM sensor, the amplitude discrimination module, and the signal acquisition module.

[0061] The DDS frequency sweeping source is mainly used to output a stable frequency sweeping signal and to gradually adjust the frequency of the frequency sweeping signal. In addition, a frequency register is set in the DDS frequency sweeping source, which is mainly used to store the frequency setting value of the frequency sweeping signal and control the output frequency of the DDS frequency sweeping source.

[0062] A phase accumulator, a waveform memory, and a digital-to-analog converter are also set in the DDS frequency sweeping source.

[0063] The phase accumulator is mainly used to generate phase information and accumulate the phase value according to the frequency control word (FTW, Frequency Tuning Word).

[0064] The waveform memory is mainly used to store standard waveform data (such as sine wave, square wave, or triangular wave).

[0065] The digital-to-analog converter is mainly used to convert the digital signal generated by the DDS module (the standard waveform data from the waveform memory) into an analog signal.

[0066] The signal conditioning circuit mainly uses gain control and digital filtering algorithms to optimize the output signal. Among them, the gain control can automatically adjust the signal amplitude to ensure that it is in the best working range, thereby improving the signal-to-noise ratio; while the digital filtering algorithm effectively suppresses the noise and spurious components in the frequency signal and provides a more stable frequency sweeping signal output.

[0067] The QCM sensor is mainly used to monitor the frequency sweeping signal, reflect the signal amplitude according to the resonance frequency change, and to monitor the signal amplitude change in real time.

[0068] In the present invention, a series resonance circuit is designed in the QCM sensor. Through the series resonance circuit, when the frequency of the DDS sweep frequency source is the resonance frequency, the voltage across the DDS sweep frequency source is much smaller than the voltage across the quartz crystal.

[0069] An amplitude discrimination module, which uses a logarithmic amplifier inside, is mainly used to detect the response of the resonance frequency and detect the signal amplitude in real time.

[0070] A signal acquisition module is mainly used to collect the voltage signal of the amplitude discrimination module in real time and feedback the signal to the single-chip microcomputer.

[0071] A QCM sensor blood coagulation detection system based on amplitude detection provided by the present invention has the following specific working process:

[0072] (1) The DDS sweep frequency source starts to work and outputs a sweep signal to the QCM sensor.

[0073] (2) Drop blood on the surface of the quartz crystal. When the blood coagulates on the surface of the quartz crystal, it will cause the resonance frequency of the quartz crystal to change; the QCM sensor monitors the sweep signal and reacts to the signal amplitude according to the change in the resonance frequency.

[0074] (3) The DDS sweep frequency source gradually adjusts the frequency of the sweep signal, and the QCM sensor monitors the change in the signal amplitude in real time.

[0075] (4) The amplitude discrimination module detects the signal amplitude in real time, and the signal is fed back to the single-chip microcomputer through the signal acquisition module using an adaptive variable step size control algorithm.

[0076] (5) Use the single-chip microcomputer to control the sweep parameters to control the sweep process of the DDS sweep frequency source; at the same time, the single-chip microcomputer uses the Kalman filtering algorithm to optimize the received signal, outputs the measurement result to the human-computer interaction module for display and the data storage module for storage; in the present invention, the output data is adjusted in real time through the Kalman filtering algorithm to reduce the measurement error and improve the accuracy and reliability of the detection result.

[0077] (7) The user can adjust the system parameters through the human-computer interaction module, and the single-chip microcomputer gives feedback and controls the sweep process.

[0078] (8) The final measurement result is displayed and output through the upper computer to complete the monitoring of the blood coagulation function.

[0079] In the present invention, the single-chip microcomputer can specifically select the STM32 chip, but is not limited thereto.

[0080] The core technologies of the present invention include the following aspects:

[0081] 1) Signal monitoring based on amplitude change;

[0082] The present invention precisely captures the changes in the coagulation state by detecting the changes in signal amplitude. When the coagulation state changes, the minute changes in blood components will lead to changes in the attached mass on the surface of the QCM sensor, thereby causing changes in the resonance frequency. By monitoring the changes in amplitude, different states of the coagulation function can be effectively reflected.

[0083] 2) Design of signal acquisition and amplitude discrimination circuit;

[0084] According to the principle of amplitude measurement, an efficient signal acquisition module and amplitude discrimination module are designed. Through the design of the signal processing and amplitude discrimination circuit, the amplitude changes of the output signal of the QCM sensor can be accurately extracted, amplified, and processed for further analysis of the coagulation state.

[0085] 3) Optimization of Kalman filter;

[0086] In order to improve the accuracy of data, the present invention introduces the Kalman filter algorithm into the single-chip microcomputer. The Kalman filter can effectively eliminate noise and interference, making the displayed coagulation function data more accurate and reliable.

[0087] 4) Driving of high-speed DDS sweep frequency source;

[0088] The present invention uses a high-speed DDS (Direct Digital Synthesizer) sweep frequency source as the signal driving circuit to ensure that the system can provide accurate and stable frequency output to meet the high requirements of the QCM sensor for frequency. The application of the high-speed DDS sweep frequency source effectively improves the response speed and stability of the system, ensuring reliability in clinical monitoring.

[0089] 5) Data interaction between the user end and the hospital end:

[0090] The human-computer interaction module can be used to send data from the user end to the hospital end through wireless communication, and the hospital end can analyze and take measures in real time based on these data.

[0091] The present invention can not only realize real-time monitoring of the coagulation function at a relatively low cost, but also break through the dependence of traditional QCM sensors on high-precision phase detection through the amplitude change monitoring method, and has a broader application prospect. Combining the Kalman filter and the high-speed DDS sweep frequency source, the present invention also significantly improves the accuracy of data and the performance of the system, and is suitable for efficient detection of the coagulation function in household or mobile medical devices.

[0092] In a second aspect, the present invention provides a method for detecting coagulation using a QCM sensor based on amplitude detection, which is mainly implemented by a system for detecting coagulation using a QCM sensor based on amplitude detection provided in the first aspect of the present invention.

[0093] See Figure 2The present invention provides a QCM sensor blood coagulation detection method based on amplitude detection, which specifically involves the following innovative aspects:

[0094] (1) During the blood coagulation process, when blood coagulates on the surface of the quartz crystal, according to the relationship between the load mass and the signal amplitude response, monitor the change in the signal amplitude during the blood coagulation process, so as to reflect the resonance frequency change curve of the quartz crystal under different blood coagulation functions, and design a corresponding signal acquisition module based on the amplitude measurement principle.

[0095] It should be noted that Sauerbrey proposed a linear relationship between the resonance frequency of the quartz crystal and the mass deposited on its surface, revealing the phenomenon that the increase in the surface mass density of the quartz crystal is proportional to the decrease in its resonance frequency. This phenomenon can be described by the Sauerbrey equation, and its specific mathematical expression is as follows:

[0096]

[0097] In the formula, The term is defined as the mass sensitivity of the quartz crystal, where, represents the square of the fundamental frequency (resonance frequency) of the quartz crystal, ρ q represents the density of the quartz crystal, v q represents the acoustic wave propagation velocity (shear mode wave velocity) of the quartz crystal; taking a 5 MHz AT-cut quartz crystal as an example, adding a substance with a surface density of 17.7 ng / cm 2 will cause a frequency shift of 1 Hz. The most important contribution of the Sauerbrey equation is to characterize that the shift of the resonance frequency is caused by the increase in the mass on the surface of the quartz crystal, and it is a linear relationship in the case of micro-increments.

[0098] The impedance formula of the equivalent circuit of the quartz crystal is as follows:

[0099]

[0100] In the formula, Z represents the total impedance in the circuit, R represents the resistance in the circuit, j represents the imaginary unit, ω represents the angular frequency of the AC signal, L represents the inductance value in the circuit, and C represents the capacitance value in the circuit.

[0101] When the equivalent circuit of the quartz crystal is at the resonant frequency, the inductance and capacitance parts of the equivalent circuit cancel each other out, leaving only the resistance. In order to establish a connection between the resonant frequency of the quartz crystal and the amplitude difference of the signal, the present invention designs a series resonant circuit such that when the frequency of the DDS frequency-sweeping source is the resonant frequency, the voltage across the DDS frequency-sweeping source is much smaller than the voltage across the quartz crystal. By adjusting the resistance value in the series resonant circuit, it is ensured that at the resonant point, the voltage across the quartz crystal is at a relatively high level, so that a significant difference is formed between the resonant frequency of the quartz crystal and the change in the amplitude of the signal. This design enables the change in the resonant frequency of the quartz crystal to be accurately detected by monitoring the amplitude change, thereby effectively reflecting the frequency fluctuation during the blood coagulation process.

[0102] Among them, the response of the quartz crystal at the resonant frequency moment is as Figure 3 shown. Two sine signals with different amplitudes, the sine signal with an amplitude of 1 represents the voltage across the signal source, and the sine signal with an amplitude of 10,000 represents the voltage across the quartz crystal. At the resonant frequency moment, the voltage across the quartz crystal will be much greater than the voltage across the signal source, and the voltage amplitude difference is very large. Therefore, this phenomenon can be used to detect the resonant frequency.

[0103] The present invention uses amplitude difference to detect the resonant frequency instead of the traditional phase detection technology, avoiding the complexity of high-precision phase detection and improving the detection efficiency.

[0104] (2) The signal source part uses a high-speed DDS (Direct Digital Frequency Synthesis) frequency-sweeping source. By adding signal conditioning circuit control, the amplitude output of the input signal is made stable. The signal conditioning circuit for signal generation and frequency acquisition ensures the stable output of the drive signal to achieve higher-precision frequency control.

[0105] The present invention utilizes the direct digital frequency synthesis technology. Starting from the phase angle, the corresponding sampling value is found in the phase of the waveform memory, and the required signal is obtained through an analog-to-digital converter, a filter, etc. Its output signal has the advantages of extremely high frequency resolution and frequency conversion rate. The DDS frequency-sweeping source can provide a stable and adjustable output frequency, which is suitable for the high-resolution resonant frequency detection requirements. Through the high-speed DDS frequency-sweeping source, the system can accurately adjust the frequency, thereby improving the working accuracy of the QCM sensor.

[0106] It should be noted that although the DDS frequency sweep source can provide high-precision frequency output, due to the particularity of its internal structure, the output signal inevitably has noise and spurious components, mainly resulting from errors caused by phase truncation, amplitude quantization, and DAC (digital-to-analog converter) conversion. These noise and spurious components may affect the stability of the signal, thereby affecting the accuracy of frequency detection. To solve this problem, the present invention uses a gain control and a digital filtering algorithm to optimize the output signal. Among them, the gain control can automatically adjust the signal amplitude to ensure that it is within the optimal working range, thereby improving the signal-to-noise ratio; while the digital filtering algorithm effectively suppresses the noise and spurious components in the frequency signal and provides a more stable frequency sweep signal output. By combining these two methods, the detection accuracy and reliability of the system are further improved, effectively avoiding the influence of noise on the system performance.

[0107] (3) The present invention adopts an adaptive variable step size control algorithm to collect amplitude information in real time and feedback it to the single-chip microcomputer, so as to adjust the frequency register in the DDS frequency sweep source through the single-chip microcomputer to achieve precise control.

[0108] It should be noted that at the DDS frequency sweep source, the present invention adopts an adaptive variable step size control algorithm. By collecting amplitude information in real time and feeding it back to the single-chip microcomputer, the frequency register in the DDS frequency sweep source is precisely adjusted. The present invention dynamically adjusts the frequency step value according to the actual situation through the adaptive variable step size control algorithm to optimize the frequency search process. Specifically, when the frequency approaches the resonance point, the step size will automatically become smaller to improve the accuracy of frequency adjustment; when it is far from the resonance point, the step size will increase to speed up the adjustment speed. This variable step size control strategy not only improves the response speed of frequency adjustment but also ensures the accuracy of the frequency locking process, thereby achieving more precise and efficient frequency control.

[0109] (4) Design an amplitude discrimination module that can accurately extract the amplitude information of the signal. This amplitude discrimination module solves the problems of signal noise and amplitude distortion through optimized circuit design, ensuring the accurate detection of amplitude changes.

[0110] It should be noted that by carefully designing the circuit and its components of the amplitude discrimination module, the amplitude information of the signal can be efficiently and accurately extracted. A logarithmic amplifier is adopted inside the amplitude discrimination module, which can convert the input signal amplitude into a voltage signal in logarithmic form. The role of the logarithmic amplifier is to convert the amplitude change of the input signal into a voltage change proportional to the logarithm of the signal amplitude, significantly reducing the influence of signal noise and amplitude distortion, and enabling the accuracy of amplitude measurement. By appropriately amplifying and filtering the signal, the amplitude discrimination module can effectively suppress external interference, improve the signal quality, and thus accurately capture the tiny changes in amplitude. In addition, the amplitude discrimination module can adapt to signal fluctuations under different working environments, further improving the stability and reliability of the system, and ensuring the accurate detection of amplitude changes.

[0111] (5) Perform real-time adjustment of the data on the output resonance frequency through Kalman filtering, so that the system is not affected by environmental or other interference factors, and realize more reliable blood coagulation function monitoring.

[0112] It should be noted that in the present invention, the Kalman filtering algorithm is used to process the output resonance frequency data in real time to reduce the influence of environmental noise or other interference factors that the system may be subjected to during the detection process. Through dynamic estimation and prediction of the frequency data, Kalman filtering can effectively smooth the measurement data, reduce the errors caused by sensor noise or external disturbances, and thus provide more accurate and stable detection results. This Kalman filtering process can not only improve the real-time responsiveness of the frequency data, but also enhance the robustness of the system, ensuring the reliability and accuracy of blood coagulation function monitoring under various working conditions.

[0113] Among them, the effect of Kalman filtering is as Figure 4 shown. Kalman filtering effectively smooths the original data. The original data is represented by black dots in the figure, showing the collected frequency signal. It can be observed that there is certain noise in the original data, manifested as small-amplitude oscillations and deviations at high frequencies. These noises may come from the instability of the measurement device, environmental interference or internal system errors. The Kalman-filtered data is represented by black crosses in the figure, showing the frequency signal after Kalman filtering. The Kalman-filtered data is smoother than the original data, significantly reducing the noise interference. This shows that Kalman filtering can effectively suppress random noise while retaining the main trend of the signal.

[0114] In the present invention, the change of the resonance frequency curve during the blood coagulation process finally obtained is as Figure 5As shown, a 13 MHz quartz crystal chip is used to detect the prothrombin time (PT). At time T1, a coagulation quality control product (plasma) is added. At time T2, after the resonant frequency of the quartz crystal stabilizes, the PT reagent is added and the coagulation reaction starts. The plasma will gradually solidify, resulting in a decrease in the resonant frequency of the quartz crystal. Time T3 is the end time of the reaction. The coagulation reaction process can be reflected according to the frequency change curve.

[0115] A method for detecting coagulation using a QCM sensor based on amplitude detection according to the present invention realizes coagulation monitoring by detecting changes in the signal amplitude. Compared with the traditional method based on phase detection, the method based on amplitude detection can effectively overcome the problems of sensitivity and accuracy in phase detection. The phase detection method may be interfered by factors such as environmental noise and signal attenuation under certain conditions, resulting in a decrease in detection accuracy. However, the amplitude detection method can provide more stable and reliable measurement results by directly analyzing the intensity change of the signal. Therefore, the QCM sensor based on amplitude detection can provide higher performance in practical applications. Especially when dynamically monitoring the blood coagulation state, it can reflect the blood coagulation process in real time and accurately, providing more accurate data support for medical monitoring.

[0116] A method and system for detecting coagulation using a QCM sensor based on amplitude detection provided by the present invention can be implemented in the form of a software functional unit and stored in a computer-readable storage medium.

[0117] Among them, the computer-readable storage medium mentioned includes but is not limited to: USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks or optical discs and other media that can store program codes.

[0118] Based on the above understanding, the technical solution of the present invention, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. The technical solution of the present invention is implemented on the ZYNQ platform in the form of a software product. The ZYNQ platform integrates an ARM processor and an FPGA (Field Programmable Gate Array), and can efficiently implement complex signal processing functions in combination with hardware and software. The ZYNQ platform can not only execute advanced algorithms such as control logic, data acquisition, and Kalman filtering, but also use its FPGA part to accelerate tasks such as signal acquisition, processing, and parallel computing.

[0119] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A QCM sensor coagulation detection method based on amplitude detection, characterized in that: The following steps are involved: (1) Start the DDS frequency sweep source and signal conditioning circuit, and use the signal conditioning circuit to control the DDS frequency sweep source to output a stable frequency sweep signal to transmit to the QCM sensor; (2) Drop blood on the surface of a quartz crystal. When the blood coagulates on the surface of the quartz crystal, the resonant frequency of the quartz crystal changes. The QCM sensor detects the frequency sweep signal and responds to the signal amplitude according to the change in the resonant frequency. (3) The DDS sweep frequency source gradually adjusts the sweep frequency signal, and the QCM sensor monitors the signal amplitude changes in real time; (4) The amplitude detection module detects the signal amplitude in real time and feeds the signal back to the microcontroller through the signal acquisition module; (5) Using the single-chip microcomputer to control the sweep frequency parameters to control the sweep frequency process of the DDS sweep frequency source; at the same time, the single-chip microcomputer uses the Kalman filter algorithm to optimize the received signal and output the measurement results to the human-computer interaction module for display and the data storage module for storage; (7) The user can adjust the system parameters through the human-computer interaction module, and the microcontroller provides feedback and controls the frequency sweep process; (8) The final measurement results are displayed and output on the host computer to complete the coagulation function monitoring.

2. The QCM sensor coagulation detection method based on amplitude detection according to claim 1, characterized in that: The increase in the surface mass density of the quartz crystal is proportional to the decrease in its resonant frequency, which is described by the Sauerbrey equation: in, The term is defined as the mass sensitivity of the quartz crystal, represents the square of the resonant frequency of the quartz crystal, ρ q represents the density of quartz crystal, v q It indicates the speed of sound wave propagation in quartz crystal; by measuring the change of resonant frequency, it reflects the change of surface quality of quartz crystal during coagulation process.

3. The QCM sensor coagulation detection method based on amplitude detection according to claim 1, characterized in that: The impedance formula of the equivalent circuit of the quartz crystal is: Wherein, Z represents the total impedance in the circuit, R represents the resistance in the circuit, j represents the imaginary unit, ω represents the angular frequency of the AC signal, L represents the inductance value in the circuit, and C represents the capacitance value in the circuit.

4. The QCM sensor coagulation detection method based on amplitude detection according to claim 3, characterized in that: When the equivalent circuit of the quartz crystal is at the resonant frequency, the inductance and capacitance of the equivalent circuit cancel each other out, and the impedance of the quartz crystal decreases sharply, causing the voltage across the quartz crystal to be much greater than the voltage across the DDS sweep source. This characteristic is used to accurately measure the resonant frequency.

5. The QCM sensor coagulation detection method based on amplitude detection according to claim 1, characterized in that: The signal conditioning circuit uses gain control and digital filtering algorithms to optimize the output signal; uses gain control to automatically adjust the signal amplitude to ensure that it is in the optimal working range; and uses a digital filtering algorithm to suppress noise and stray components in the frequency signal to output a stable swept frequency signal.

6. The QCM sensor coagulation detection method based on amplitude detection according to claim 1, characterized in that: In step (4), an adaptive variable step-size control algorithm is used to accurately adjust the frequency register in the DDS frequency sweep source by collecting amplitude information in real time and feeding it back to the microcontroller.

7. The QCM sensor coagulation detection method based on amplitude detection according to claim 1, characterized in that: The amplitude detection module uses a logarithmic amplifier to convert the input signal amplitude into a voltage signal in logarithmic form.

8. A QCM sensor coagulation detection system based on amplitude detection, characterized in that: include: Cloud display module, data storage module, human-computer interaction module, single-chip microcomputer, power supply module, DDS frequency sweep source, signal conditioning circuit, QCM sensor, amplitude detection module and signal acquisition module; The cloud display module is used to upload the collected experimental data to the cloud display module in real time, so that users can view the change curve of the quartz crystal resonant frequency through mobile phones, computers or other terminal devices; A data storage module is used to locally store the collected resonant frequency data for use by the cloud display module; and for subsequent analysis and comparison of experimental results; Human-computer interaction module, used to manually adjust and control system parameters to adapt to quartz crystals with different resonant frequencies; And receive the data fed back by the microcontroller; The single chip microcomputer is used to control the frequency sweeping parameters so as to control the frequency sweeping process of the DDS frequency sweeping source; and for optimizing the signal sent by the signal acquisition module using a Kalman filter algorithm; and for feeding back data to the human-computer interaction module; The power supply module is used to supply power to the single-chip microcomputer, DDS frequency sweep source, QCM sensor, amplitude detection module and signal acquisition module; DDS sweep frequency source, used to output a stable sweep frequency signal and to gradually adjust the sweep frequency signal frequency; The signal conditioning circuit is used to amplify and filter the signal output by the QCM sensor to improve the signal quality and ensure that the subsequent signal acquisition module can accurately obtain the resonant frequency and amplitude information; QCM sensor, used to monitor the swept frequency signal and respond to the signal amplitude according to the change of the resonant frequency, and used to monitor the change of the signal amplitude in real time; The amplitude detection module uses a logarithmic amplifier to detect the response of the resonant frequency and detect the signal amplitude in real time; The signal acquisition module is used to collect the voltage signal of the amplitude detection module in real time and feed the signal back to the microcontroller.

9. The QCM sensor coagulation detection system based on amplitude detection according to claim 8, characterized in that: The human-computer interaction module includes: a host computer display module, an LCD screen display module, a button control module and a touch screen control module; the host computer display module is used to display the resonant frequency change curve in the mobile terminal, the LCD screen display module is used to display the resonant frequency change curve on the system, the button control module is used to adjust the parameters of the sweep module, and the touch screen control module is used to switch the sweep mode and reset the system.

10. The QCM sensor coagulation detection system based on amplitude detection according to claim 8, characterized in that: The DDS frequency sweep source is provided with a frequency register, a phase accumulator, a waveform memory and a digital-to-analog converter; the frequency register is used to store the frequency setting value of the frequency sweep signal and control the output frequency of the DDS frequency sweep source; the phase accumulator is used to generate phase information and accumulate the phase value according to the frequency control word; the waveform memory is used to store standard waveform data; the digital-to-analog converter is used to convert the digital signal generated by the DDS module into an analog signal.

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