A multi-component gas synchronous detection device and method based on differential filter modulation

Abstract

The application discloses a multi-component gas synchronous detection device and method based on differential filter modulation. The device comprises a multi-waveband light source module, a differential filter modulation module, a photoelectric detection module and an information processing module. The differential filter modulation module comprises a gas filter disc integrating multiple filter units. Each filter unit comprises a reference cell filled with high-concentration to-be-detected gas and a measurement cell filled with inert gas or a cavity. The photoelectric detection module comprises a long optical path absorption cell through which mixed gas to be detected is introduced in real time. The multi-waveband light source module emits multiple discrete waveband light signals in time division. The gas filter disc makes the light signals alternately pass through the corresponding reference cell and measurement cell through reciprocating swing, so that the light signals are obtained after differential modulation. The modulated light signals are attenuated after passing through the long optical path absorption cell and are then converted into electric signals. The information processing module demodulates the electric signals and calculates the concentration of the to-be-detected gas in the mixed gas through a differential absorption algorithm, so that the synchronous detection of the multi-component gas is realized.

Description

Technical Field

[0001] This application relates to the field of gas detection technology, and relates to, but is not limited to, a device and method for synchronous detection of multi-component gases based on differential filter modulation. Background Technology

[0002] Optical absorption spectroscopy, especially non-dispersive infrared (NDIR) technology, is widely used in gas detection in environmental monitoring, industrial process control, and safety early warning systems due to its high selectivity, high sensitivity, and fast response. For the detection of multi-component gases, traditional methods typically employ multiple single-gas sensors for independent detection, resulting in complex systems, high costs, and difficulties in ensuring synchronization.

[0003] In related technologies, to address the need for multi-component gas detection, there are mainly two types of techniques based on the principle of optical absorption. First, a broadband infrared light source emits a continuous spectrum. A motor drives a filter wheel to rotate, causing bandpass filters with different center wavelengths to sequentially enter the optical path, thereby acquiring the characteristic absorption signals of different gases in a time-division manner. Second, a broadband light source combined with differential optical absorption spectroscopy (DOAS) technology is used. Using a broadband light source such as a xenon lamp, a high-resolution continuous spectrum is obtained after dispersion by the spectrometer. Qualitative and quantitative analysis is then performed by analyzing the gas absorption fingerprint structure within specific wavelength bands.

[0004] However, in the broadband light source combined with a rotating filter wheel scheme, the energy dispersion of the broadband light source leads to a low signal-to-noise ratio, and the precise angle control required for the rotating filter wheel results in a complex overall device structure. Furthermore, the time-division measurement mechanism also limits the response speed. In the broadband light source combined with a spectrometer scheme, the spectrometer equipment is expensive and bulky. Both of these technologies struggle to effectively suppress real-time common-mode noise and have limited ability to compensate for common interferences such as light source fluctuations, resulting in low accuracy in detecting multi-component gases in air. Summary of the Invention

[0005] In view of this, embodiments of this application provide a multi-component gas synchronous detection device and method based on differential filter modulation, which at least solves the problems of complex device structure and low accuracy of gas concentration detection for multi-component gas detection.

[0006] The technical solution of this application embodiment is implemented as follows:

[0007] In a first aspect, embodiments of this application provide a multi-component gas synchronous detection device based on differential filtering modulation, comprising: a multi-band light source module, a differential filtering modulation module, a photoelectric detection module, and an information processing module; the differential filtering modulation module includes a gas filter disk and a position sensor; the gas filter disk integrates multiple sets of filtering units; each set of filtering units includes a reference cell and a measurement cell, each reference cell is filled with a high concentration of the corresponding gas to be measured, and each measurement cell is filled with a non-polar inert gas or is a cavity; the photoelectric detection module includes a long optical path absorption cell, into which a mixed gas containing the gas to be measured is continuously introduced;

[0008] The multi-band light source module is used to emit optical signals of multiple discrete bands corresponding to the characteristic absorption peaks of the various gases to be tested in a time-division sequential manner.

[0009] The differential filtering modulation module is used to drive the optical signal corresponding to the gas under test to alternately pass through the reference cell and the measurement cell of the corresponding filtering unit in the gas filtering disk through the reciprocating oscillation of the gas filtering disk, so as to differentially modulate the current optical signal and obtain a modulated optical signal; wherein, the portion of the optical signal passing through the reference cell constitutes the reference optical component of the modulated optical signal, and the portion of the optical signal passing through the measurement cell constitutes the measurement optical component of the modulated optical signal; the current oscillation phase of the gas filtering disk is detected by the position sensor to generate a synchronization signal, and the synchronization signal is sent to the information processing module;

[0010] The photoelectric detection module is used to guide the modulated optical signal to be absorbed and attenuated by the corresponding gas to be tested in the mixed gas, and then converted into a corresponding electrical signal.

[0011] The information processing module is used to synchronously demodulate the measurement light signal intensity corresponding to the current measurement light component and the reference light signal intensity corresponding to the current reference light component from the electrical signal based on the synchronization signal; and to calculate the concentration of the gas to be measured based on the measurement light signal intensity and the reference light signal intensity, until the concentration detection of multiple gases to be measured is completed.

[0012] Secondly, embodiments of this application provide a method for simultaneous detection of multi-component gases based on differential filtering modulation, applied to a multi-component gas simultaneous detection device. The device includes: a multi-band light source module, a differential filtering modulation module, a photoelectric detection module, and an information processing module. The differential filtering modulation module includes a gas filter disk and a position sensor. Multiple filtering units are integrated on the gas filter disk. Each filtering unit includes a reference cell and a measurement cell. Each reference cell is filled with a high concentration of the corresponding gas to be measured, and each measurement cell is filled with a non-polar inert gas or is a cavity. The photoelectric detection module includes a long-path absorption cell, into which a mixed gas containing the gas to be measured is continuously introduced. The method includes:

[0013] Using the multi-band light source module, optical signals of multiple discrete bands corresponding to the characteristic absorption peaks of various gases to be tested are emitted sequentially in a time-division manner.

[0014] Using the differential filtering modulation module, the reciprocating oscillation of the gas filter disk drives the optical signal corresponding to the gas under test to alternately pass through the reference cell and the measurement cell of the corresponding filter unit in the gas filter disk, thereby differentially modulating the current optical signal to obtain a modulated optical signal. The portion of the optical signal passing through the reference cell constitutes the reference optical component of the modulated optical signal, and the portion of the optical signal passing through the measurement cell constitutes the measurement optical component of the modulated optical signal. The position sensor detects the current oscillation phase of the gas filter disk to generate a synchronization signal, which is then sent to the information processing module.

[0015] Using the photoelectric detection module, the modulated optical signal is guided to be absorbed and attenuated by the corresponding gas to be tested in the mixed gas, and then converted into a corresponding electrical signal;

[0016] Using the information processing module, based on the synchronization signal, the intensity of the measured optical signal corresponding to the current measured optical component and the intensity of the reference optical signal corresponding to the current reference optical component are synchronously demodulated from the electrical signal; based on the intensity of the measured optical signal and the intensity of the reference optical signal, the concentration of the gas to be measured is calculated until the concentration detection of multiple gases to be measured is completed.

[0017] The beneficial effects of the technical solutions provided in this application include at least the following:

[0018] This application utilizes a multi-band light source module to sequentially emit multiple discrete-band optical signals in a time-division manner. Each band of optical signal corresponds to a characteristic absorption peak of a specific gas being measured, meaning each band of optical signal can be absorbed by a specific gas. This allows the device to be reused for all gases being measured. This highly integrated device is compact and enables cost reduction in the synchronous detection of multi-component gases. The gas filter disk integrates multiple filter units containing reference and measurement cells. Through reciprocating oscillation, the current optical signal alternately passes through the reference and measurement cells for differential modulation. Based on the differential technology carried by the measurement and reference optical components of the modulated optical signal, common-mode noise caused by optical signal intensity fluctuations and device aging can be effectively suppressed, significantly improving the signal-to-noise ratio and measurement stability of the device. The synchronization signal generated by the position sensor corresponds to the oscillation phase of the gas filter disk and is a key time stamp for distinguishing the measurement and reference optical components. The photoelectric detection module guides the modulated optical signal to be absorbed and attenuated by the current gas being measured in the gas mixture. For the same concentration of gas being measured, the attenuation of the optical signal after passing through the long optical path absorption cell is amplified exponentially. This signal amplification effect enables the device to sensitively detect subtle absorption changes caused by low concentrations of the analyte gas, thereby achieving accurate measurement of the current analyte gas. The concentration of the current analyte gas is calculated based on the measured light intensity and the reference light intensity, canceling common-mode noise and improving the accuracy of detecting the concentration of each analyte gas. This process is repeated until the concentration of all analytes is detected in a preset order. Therefore, this application achieves simultaneous detection of multiple components of gas through a highly integrated device. This highly integrated device reduces costs, suppresses common-mode noise to improve detection accuracy, and significantly improves the device's response speed through time-division multiplexing of optical signals and synchronous modulation of optical signals. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0020] Figure 1 A schematic diagram of the overall structure of a multi-component gas synchronous detection device based on differential filter modulation provided in this application embodiment;

[0021] Figure 2 A schematic diagram of the specific structure of the device provided in the embodiments of this application;

[0022] Figure 3 A schematic diagram of the LED light source array of the device provided in the embodiments of this application;

[0023] Figure 4 A schematic diagram of the front structure of the gas filter disk of the device provided in the embodiments of this application;

[0024] Figure 5 A timing diagram illustrating the timing drive and synchronous acquisition and demodulation of signals during operation of the device provided in this application embodiment;

[0025] Figure 6 This is a flowchart illustrating a method for synchronous detection of multi-component gases based on differential filter modulation, provided in an embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. The following embodiments are used to illustrate this application, but are not intended to limit the scope of this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0028] It should be noted that the terms "first, second, and third" used in the embodiments of this application are merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first, second, and third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0029] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of this application pertain. It should also be understood that terms such as those defined in general dictionaries should be understood to have a meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0030] Figure 1 A schematic diagram of the overall structure of a multi-component gas synchronous detection device based on differential filter modulation provided in this application embodiment is shown below. Figure 1As shown, this application proposes a multi-component gas synchronous detection device 100 based on differential filtering modulation, including: a multi-band light source module 110, a differential filtering modulation module 120, a photoelectric detection module 130, and an information processing module 140; the differential filtering modulation module 120 includes a gas filter disk 1201 and a position sensor 1202; the gas filter disk 1201 integrates multiple sets of filtering units; each set of filtering units includes a reference cell R and a measurement cell M, each reference cell is filled with a high concentration of the corresponding gas to be measured, and each measurement cell is filled with a non-polar inert gas or is a cavity; the photoelectric detection module 130 includes a long optical path absorption cell 1301, and a mixed gas containing the gas to be measured is continuously introduced into the long optical path absorption cell;

[0031] The multi-band light source module 110 is used to emit optical signals of multiple discrete bands corresponding to the characteristic absorption peaks of the various gases to be tested in a time-division sequential manner.

[0032] A multi-band light source module can generate light of multiple specific wavelengths, emitting different wavelengths sequentially to detect various gases and their concentrations. The characteristic absorption peak of a gas is the property of each gas to strongly absorb light of a specific wavelength. This specific wavelength is the key optical basis for identifying the corresponding analyte gas and measuring its concentration. Discrete-band light signals are independent, narrow-range, and discontinuous light waves. Each discrete band is selected to match the characteristic absorption wavelength of a corresponding analyte gas. For example, when simultaneously detecting methane, carbon monoxide, and ammonia and their concentrations, the multi-band light source module emits three discrete-band light signals sequentially in a time-division manner, so that they are absorbed by each of the three analyte gases respectively.

[0033] Based on the characteristic absorption peak of each gas to be tested, a discrete wavelength band is pre-defined for each gas, with the center wavelength of the band matching the characteristic absorption peak wavelength of the corresponding gas. When the multi-band light source module emits light of this specific wavelength band, it is primarily absorbed by the corresponding gas to be tested, thus achieving selective detection of the gas to be tested.

[0034] The differential filtering modulation module 120 is used to drive the optical signal corresponding to the gas under test to alternately pass through the reference cell and the measurement cell of the corresponding filtering unit in the gas filtering disk through the reciprocating oscillation of the gas filtering disk, so as to differentially modulate the current optical signal to obtain a modulated optical signal; wherein, the portion of the optical signal passing through the reference cell constitutes the reference optical component of the modulated optical signal, and the portion of the optical signal passing through the measurement cell constitutes the measurement optical component of the modulated optical signal; the current oscillation phase of the gas filtering disk is detected by the position sensor to generate a synchronization signal, and the synchronization signal is sent to the information processing module;

[0035] The differential filtering modulation module uses the periodic reciprocating oscillation of the gas filter disk to physically modulate the incident optical signal targeting the gas to be measured.

[0036] In some embodiments, the number of filter units in the gas filter disk can be one or more, and the operator can adapt the number of filter units to meet actual needs. This arrangement of the number of filter units enables the device of this application to detect not only multi-component gases, but also single-type gases and their concentrations.

[0037] The differential filtering and modulation module drives the optical signal to alternately pass through the reference cell and the measurement cell in the filter unit corresponding to the gas being measured during the reciprocating oscillation of the disk. This alternating passage through the reference and measurement cells completes the differential modulation of the optical signal, transforming a continuous optical signal into a modulated optical signal whose intensity changes periodically with time. The modulated optical signal contains two physical components: a reference optical component and a measurement optical component.

[0038] (1) The reference light component is obtained by modulating the light signal passing through the reference cell each time. Since the reference cell is filled with a high concentration of the gas to be measured corresponding to the wavelength of the current light signal, the light signal passing through the reference cell is strongly absorbed, and the intensity of the light signal after passing through the reference cell represents a reference reference that is almost completely absorbed.

[0039] (2) The measured light component is obtained by modulating the light signal passing through the measuring cell each time. Since the measuring cell is filled with inert gas or a cavity, the light signal passing through the measuring cell is almost completely absorbed. The intensity of the light signal after passing through the measuring cell mainly reflects the initial intensity of the light source and the inherent losses inside the device.

[0040] A position sensor mounted on the disk detects the current swing phase of the disk in real time. A synchronization signal, identical to the one used during the optical signal switching process, is generated based on this current swing phase and sent to the information processing module. This synchronization signal serves as a time reference for the subsequent information processing module to accurately identify and separate the intensities corresponding to the reference and measured optical components from the mixed electrical signals.

[0041] The photoelectric detection module 130 is used to guide the modulated optical signal to be absorbed and attenuated by the corresponding gas to be tested in the mixed gas, and then converted into a corresponding electrical signal.

[0042] The photoelectric detection module guides the modulated optical signal, carrying reference and measurement optical components, output from the differential filtering modulation module, to interact with the gas mixture to be measured. This causes the modulated optical signal to be absorbed by the corresponding component of the gas mixture currently being measured. The wavelength of the optical signal corresponds to the characteristic absorption peak of the gas being measured, ensuring that the attenuation of the modulated optical signal sensitively reflects the concentration of the gas being measured.

[0043] After the modulated optical signal intensity is attenuated by the gas being measured, photoelectric conversion is performed to convert the attenuated optical signal carrying concentration information into a corresponding electrical signal. For example, the electrical signal can be a current signal or a voltage signal.

[0044] The information processing module 140 is used to synchronously demodulate the measurement light signal intensity corresponding to the current measurement light component and the reference light signal intensity corresponding to the current reference light component from the electrical signal based on the synchronization signal; and to calculate the concentration of the gas to be measured based on the measurement light signal intensity and the reference light signal intensity, until the concentration detection of multiple gases to be measured is completed.

[0045] The information processing module receives a mixed electrical signal from the photoelectric detection module and a synchronization signal from the position sensor. The synchronization signal corresponds to the swing phase of the gas filter disk and is a key time stamp that distinguishes the measured light component from the reference light component.

[0046] The information processing module performs synchronous demodulation on the mixed electrical signals and, based on the synchronization signal, separates the measured optical signal intensity corresponding to the current measured optical component and the reference optical signal intensity corresponding to the current reference optical component from the time-mixed electrical signals.

[0047] The information processing module performs mathematical calculations on the intensity of the measured optical signal and the intensity of the reference optical signal to eliminate common-mode interference and calculate a physical quantity related to the current concentration of the gas to be measured. For example, the mathematical calculation can be a ratio, difference, or other algorithmic processing, and the physical quantity can be differential absorbance. Subsequently, based on the preset correspondence between the physical quantity and the gas concentration, the concentration of the current gas to be measured is calculated.

[0048] After completing the detection of one gas to be tested, the device automatically switches to the light source and filter unit corresponding to the next gas to be tested under the coordination of the above synchronization signal, and repeats the above process until the concentration detection of all gases to be tested is completed in a preset order, so as to realize the sequential and synchronous detection of multi-component gases.

[0049] This application utilizes a multi-band light source module to sequentially emit multiple discrete-band optical signals in a time-division manner. Each band of optical signal corresponds to a characteristic absorption peak of a specific gas being measured, meaning each band of optical signal can be absorbed by a specific gas. This allows the device to be reused for all gases being measured. This highly integrated device is compact and enables cost reduction in the synchronous detection of multi-component gases. The gas filter disk integrates multiple filter units containing reference and measurement cells. Through reciprocating oscillation, the current optical signal alternately passes through the reference and measurement cells for differential modulation. Based on the differential technology carried by the measurement and reference optical components of the modulated optical signal, common-mode noise caused by optical signal intensity fluctuations and device aging can be effectively suppressed, significantly improving the signal-to-noise ratio and measurement stability of the device. The synchronization signal generated by the position sensor corresponds to the oscillation phase of the gas filter disk and is a key time stamp for distinguishing the measurement and reference optical components. The photoelectric detection module guides the modulated optical signal to be absorbed and attenuated by the current gas being measured in the gas mixture. For the same concentration of gas being measured, the attenuation of the optical signal after passing through the long optical path absorption cell is amplified exponentially. This signal amplification effect enables the device to sensitively detect subtle absorption changes caused by low concentrations of the analyte gas, thereby achieving accurate measurement of the current analyte gas. The concentration of the current analyte gas is calculated based on the measured light intensity and the reference light intensity, canceling common-mode noise and improving the accuracy of detecting the concentration of each analyte gas. This process is repeated until the concentration of all analytes is detected in a preset order. Therefore, this application achieves simultaneous detection of multiple components of gas through a highly integrated device. This highly integrated device reduces costs, suppresses common-mode noise to improve detection accuracy, and significantly improves the device's response speed through time-division multiplexing of optical signals and synchronous modulation of optical signals.

[0050] Figure 2 A schematic diagram of the specific structure of the device provided in the embodiments of this application is shown below. The following is a detailed description of the device... Figure 2 This application describes a multi-component gas synchronous detection device based on differential filter modulation.

[0051] In some embodiments, the multi-band light source module includes a timing drive circuit 1101, an LED light source array 1102, and a collimating lens group 1103; the LED light source array includes multiple LED chips that emit different center wavelengths.

[0052] The timing drive circuit is electrically connected to the position sensor; the timing drive circuit illuminates each LED chip sequentially according to the synchronization signal to generate multiple discrete wavelength band optical signals in a time-division sequence; the timing of illuminating each LED chip coincides with the timing of the corresponding filter unit on the gas filter disk entering the effective area of ​​the optical signal; the emission center wavelength of each LED chip corresponds to the characteristic absorption peak of one of the gases to be measured;

[0053] The collimating lens group is disposed at the optical path output end of each LED chip and is used to collimate the optical signal emitted by the LED chip.

[0054] Figure 3 This is a schematic diagram of the LED light source array of the device provided in the embodiments of this application. Figure 3 As shown, the gas filter disk integrates 8 filter units, specifically including: filter unit 1 [reference cell R1, measurement cell M1]; filter unit 2 [reference cell R2, measurement cell M2]; filter unit 3 [reference cell R3, measurement cell M3]; filter unit 4 [reference cell R4, measurement cell M4]; filter unit 5 [reference cell R5, measurement cell M5]; filter unit 6 [reference cell R6, measurement cell M6]; filter unit 7 [reference cell R7, measurement cell M7]; and filter unit 8 [reference cell R8, measurement cell M8].

[0055] Figure 3 In this example, the number of filter units, the number of reference cells, and the number of measurement cells are all 8. This number is only an example and does not constitute a limitation on the number of filter units, the number of reference cells, and the number of measurement cells in the device of this application.

[0056] Each LED chip emits infrared light at the center wavelength corresponding to the gas being tested. These multiple wavelengths correspond one-to-one with the characteristic absorption peaks of various gases being tested.

[0057] The timing drive circuit illuminates multiple LED chips at a certain frequency, with the same number of LED chips as the gas to be tested emitting light signals at any given moment.

[0058] The collimating lens group includes multiple collimating lenses corresponding to the number of LED chips. Each collimating lens is positioned on the light-emitting path of an LED chip to convert the divergent light emitted by the LED chip into parallel light, thereby reducing light signal diffusion and light signal energy loss.

[0059] In some embodiments, each LED chip is individually configured with a collimating lens, and each collimating lens can be a plano-convex lens or an aspherical lens. Multiple collimating lenses can be integrated on a support or substrate to form a collimating lens group.

[0060] In some embodiments, when detecting the gas mixture to be tested, the number of LED chips, the number of filter units, the number of collimating lenses, and the number of gas components to be tested are all the same value, and can all be any natural number. For example, when the number of gas components to be tested is 3, the number of LED chips used is 3, and the number of filter units used is 3.

[0061] In some embodiments, when designing the apparatus of this application, the number of LED chips, the number of collimating lenses, and the number of filtering units are set to large integers. The apparatus can pre-integrate more LED chips, collimating lenses, and filtering units than currently required for detection. This design provides the apparatus with greater flexibility to adapt to the detection needs of different component gases without changing the hardware structure of the apparatus. For example, the number of LED chips, the number of collimating lenses, and the number of filtering units are all 8.

[0062] In some embodiments, the number of LED chips, collimating lenses, and filtering units in the device of this application are all flexibly set parameters, which can be reduced or increased according to the amount of gas to be measured. This design improves the scalability of the device. For example, when the amount of gas components to be measured is 5, the number of LED chips, collimating lenses, and filtering units are correspondingly configured to be 5.

[0063] In some embodiments, the differential filtering modulation module further includes a drive motor 1203 and a first optical lens 1204;

[0064] The drive motor is connected to the gas filter disk, and the drive motor is used to drive the gas filter disk to reciprocate at a fixed angle.

[0065] Multiple sets of filtering units are integrated on the gas filter disk along its circumference; the reference cell and the measurement cell in each set of filtering units are arranged adjacent to each other; each reference cell is used to absorb the optical signal passing through the reference cell to obtain the reference optical component of the modulated optical signal; each measurement cell is used to maintain the intensity of the optical signal passing through the measurement cell to obtain the measurement optical component of the modulated optical signal.

[0066] The first optical lens is disposed at the light outlet of the gas filter disk and is used to couple the light signal modulated by the gas filter disk into the photoelectric detection module.

[0067] Figure 4 This is a front structural diagram of the gas filter disk of the device provided in an embodiment of this application. Figure 4As shown, the reference cell and the measurement cell are integrated in pairs, adjacent to each other, within the various filter units of the gas filter disk. The reference cell and the measurement cell can be arranged as parallel optical channels.

[0068] The reference cell and the measurement cell are arranged side by side, sharing the same optical inlet and outlet channels. As the gas filter disk oscillates back and forth, the incident light signal alternately switches from passing through the reference cell to passing through the measurement cell.

[0069] The reference cell is sealed and filled with a high concentration of pure analyte gas, serving to provide an optical reference for complete or strong absorption. For example, when the analyte gas is carbon dioxide, the reference cell is sealed and filled with a high concentration of pure carbon dioxide.

[0070] The measuring cell is sealed and filled with a nonpolar inert gas or is a cavity, which serves to provide an optical channel in which all the gases to be measured are completely unabsorbed or absorb negligibly. For example, the nonpolar inert gas can be nitrogen, helium, or argon, and the cavity can be a vacuum or dry air, which are filling materials that produce almost no absorption effect on the optical signals corresponding to all the gases to be measured.

[0071] The gas filter disk oscillates at a fixed angle during its reciprocating motion; this fixed angle is related to the width of the filter unit. The drive motor can be a stepper motor or a voice coil motor.

[0072] The first optical lens can be a focusing lens, which can converge the light signal, which may have diverged after passing through the gas filter disk, to a focal point, that is, to the input port of the long optical path absorption cell in the photoelectric detection module.

[0073] In some embodiments, the photoelectric detection module further includes: a second optical lens 1302 and a single-point photodetector 1303;

[0074] The long optical path absorption cell 1301 is used to absorb and attenuate the modulated optical signal to obtain an attenuated optical signal; the long optical path absorption cell is a White type or a Herriott type multiple reflection cell.

[0075] The second optical lens 1302 is disposed between the output light port of the long optical path absorption cell and the single-point photodetector, and is used to converge the attenuated light signal output from the long optical path absorption cell onto the photosensitive surface of the single-point photodetector.

[0076] The single-point photodetector 1303 is disposed at the output port of the long optical path absorption cell and is used to convert the attenuated optical signal into the electrical signal.

[0077] The long optical path absorption cell significantly extends the optical path of the interaction between the modulated optical signal and the gas to be measured, thus amplifying the concentration information of the gas to be measured into the attenuation of the optical signal.

[0078] The second optical lens can be a focusing lens, which converges the beam of light, which may diverge after passing through the long optical path absorption cell, to a single focal point. The second optical lens is positioned at the output end of the attenuated optical signal after passing through the long optical path absorption cell.

[0079] A single-point photodetector can be a thermopile or a photodiode. It can be placed at the exit port of a long-path absorption cell to complete the photoelectric conversion. It receives the attenuated light signal after it has been focused by an optical lens and converts the changes in light signal intensity into corresponding electrical signals in real time. These electrical signals serve as the data source for subsequent synchronous demodulation and concentration calculation.

[0080] In some embodiments, the information processing module 140 includes an analog-to-digital conversion acquisition circuit 1401 and a processor 1402;

[0081] The input terminal of the analog-to-digital conversion acquisition circuit 1401 is electrically connected to the output terminal of the photoelectric detection module, and is used to acquire the electrical signal output by the photoelectric detection module in real time and convert the electrical signal into a digital signal.

[0082] The input terminal of the processor 1402 is electrically connected to the output terminal of the analog-to-digital conversion acquisition circuit, and is used to receive the corresponding digital signal;

[0083] The input terminal of the processor 1402 is electrically connected to the position sensor and is used to receive the synchronization signal to obtain the real-time swing phase of the gas filter disk.

[0084] The output terminal of the processor 1402 is electrically connected to the timing drive circuit and is used to send control commands to the timing drive circuit to control the time-division lighting sequence of each LED chip.

[0085] The output terminal of the processor 1402 is electrically connected to the drive motor and is used to send control signals to the drive motor to control the oscillation frequency and oscillation amplitude of the gas filter disk reciprocating.

[0086] The processor 1402 is further configured to synchronously demodulate the measurement light signal intensity corresponding to the current measurement light component and the reference light signal intensity corresponding to the current reference light component from the digital signal, and calculate the concentration of the current gas to be measured by inversion through differential absorption algorithm based on the measurement light signal intensity and the reference light signal intensity.

[0087] The processor can be a microcontroller unit (MCU), which integrates signal processing algorithms. For example, the signal processing algorithm could be a differential absorption algorithm.

[0088] In some embodiments, the apparatus of this application completes the detection of multiple target gases by performing the following steps:

[0089] S1. Using a timing drive circuit, the LED chips in the LED light source array are lit up cyclically and in a time-division manner according to a preset wavelength sequence. For example, the wavelength sequence is first wavelength λ1, second wavelength λ2, third wavelength λ3, and so on in a cyclic manner.

[0090] S2. While the LED chips are lit in a time-sharing manner, a drive motor drives a gas filter disk to reciprocate. The oscillation frequency of the gas filter disk is synchronized with the lighting sequence of the LED chips, ensuring that when a light signal of a specific wavelength is emitted, the gas filter disk oscillates so that the light signal can pass through the filter unit corresponding to the current wavelength.

[0091] S3. By utilizing the oscillation of the gas filter disk, the optical signal is driven to alternately pass through the reference cell and the measurement cell of the current filter unit, thereby completing differential modulation. The optical signal passing through the reference cell is strongly absorbed by the high concentration of the corresponding gas in the reference cell, forming the reference light component in the modulated optical signal; the intensity of the optical signal passing through the measurement cell is maintained, forming the measurement light component.

[0092] S4. The differentially modulated optical signal is guided into the long optical path absorption cell. A mixed gas containing the gas to be measured is continuously introduced into the long optical path absorption cell. The optical signal interacts with the current gas to be measured in the mixed gas within the long optical path absorption cell. The optical signal component whose wavelength matches the characteristic absorption peak of the gas is absorbed by the current gas to be measured and undergoes secondary attenuation. This process loads the concentration information of the current gas to be measured onto the optical signal intensity, resulting in the attenuated optical signal.

[0093] S5. Using a single-point photodetector, the attenuated optical signal emitted from the long optical path absorption cell is received, and the attenuated optical signal is converted into a series of electrical signals that vary with the modulation timing.

[0094] S6. The information processing module receives the synchronization signal from the position sensor and, based on the synchronization signal, synchronously demodulates the measured light signal intensity V corresponding to the lighting period of each LED chip from the electrical signal obtained in S5. signal_λn With reference optical signal intensity V ref_λn .

[0095] S7. For each gas to be tested, the information processing module executes the differential absorption algorithm. The differential absorption algorithm uses the measured optical signal intensity V demodulated in S6. signal_λnWith reference optical signal intensity V ref_λn The differential absorbance of the current gas is calculated. As shown in formula (1):

[0096] Formula (1);

[0097] S8. According to Beer-Lambert Law, absorbance A D The concentration is directly proportional to the concentration of the gas in the long-path absorption cell. Using a pre-calibrated and stored concentration-absorbance preset relationship, the differential absorbance calculated in S7 is inverted to determine the current concentration of the gas to be measured in the long-path absorption cell. The device operates cyclically according to the above steps until the concentration of all gas components to be measured is detected.

[0098] Figure 5 This is a timing diagram illustrating the timing drive and signal synchronization acquisition and demodulation during operation of the device provided in this application embodiment. (See diagram below.) Figure 5 As shown, an example is given with three quantities of the gas to be tested, three LED chips, and three filter units. The three LED chips are LED1, LED2, and LED3. The multi-band light source module illuminates LED1, LED2, and LED3 in a preset time sequence. The preset time sequence includes three time periods: T1, T2, and T3.

[0099] Figure 5 In the process, during time period T1, LED1 is illuminated, emitting a light signal at the characteristic absorption wavelength of the first gas to be tested, and the device enters the detection cycle for the first gas to be tested. The same process applies to time periods T2 and T3, sequentially switching to LED2 and LED3 to detect the second and third gases to be tested, respectively. This achieves time-series multiplexing of multiple gases to be tested.

[0100] Figure 5 In this process, during the detection period of each gas to be tested, the gas filter disk oscillates at high speed, and the synchronization signal of its oscillation phase is provided by... Figure 5 The image shows a sawtooth waveform. The peaks and troughs of the sawtooth waveform correspond to the physical positions of the optical signal as it passes through the current measurement cell and reference cell, respectively. The continuous oscillation of the gas filter disk drives the periodic alternation of the optical signal between the measurement cell and the reference cell, completing differential modulation and obtaining the modulated optical signal.

[0101] Figure 5 In the process, when the gas filter disk swings to the crest, which is when the light signal passes through the current measurement cell, the electrical signal output by the photodetector is sampled at the moment indicated by the solid arrow. This sampled value represents the electrical signal component of the measurement light in the electrical signal.

[0102] Figure 5In the process, when the gas filter disk swings to the trough, which is when the optical signal passes through the current reference cell, it is sampled at the moment indicated by the dashed arrow. This sampled value represents the electrical signal component of the reference light in the electrical signal.

[0103] In some embodiments, the apparatus of this application has the following beneficial effects:

[0104] (1) High synchronization and high efficiency: By using a single-point photodetector in conjunction with a time-illuminated light source and a swing-type modulation disk, the synchronous or quasi-synchronous detection of multi-component gases is achieved, avoiding the high cost and inconsistency problems caused by using multiple single-point photodetectors. The device of this application has a fast response speed.

[0105] (2) Strong anti-interference capability: The reciprocating swing differential filter modulation design enables the optical signal passing through the measurement cell and the optical signal passing through the reference cell to alternate rapidly in time, effectively suppressing common-mode noise caused by fluctuations in light source intensity, optical window contamination, detector aging, etc., and significantly improving the signal-to-noise ratio and measurement stability.

[0106] (3) High selectivity and sensitivity: A discrete LED light source that matches the characteristic absorption peak of the gas to be measured is used. This light source has concentrated energy and high utilization rate. Combined with a long optical path absorption cell, the absorption of the gas to be measured by the corresponding light signal is enhanced, and high sensitivity detection of low concentration of gas to be measured is achieved.

[0107] (4) Simple and reliable structure: Compared with continuous rotation, the oscillating motion of the gas filter disk does not require complex angle coding and positioning, making control simple, the mechanical structure more stable, the lifespan longer, and reducing the manufacturing and maintenance costs of the device.

[0108] (5) Easy to expand: By increasing the number of LED chips and corresponding filter units on the gas filter disk, the types of gases that can be detected can be expanded, making the device highly flexible.

[0109] Figure 6 A flowchart illustrating a method for simultaneous detection of multi-component gases based on differential filter modulation, as provided in this application embodiment, is shown below. Figure 6As shown, this application provides a method for simultaneous detection of multi-component gases based on differential filtering modulation, applied to a multi-component gas simultaneous detection device. The device includes: a multi-band light source module, a differential filtering modulation module, a photoelectric detection module, and an information processing module. The differential filtering modulation module includes a gas filter disk and a position sensor. Multiple sets of filtering units are integrated on the gas filter disk. Each set of filtering units includes a reference cell and a measurement cell. Each reference cell is filled with a high concentration of the corresponding gas to be measured, and each measurement cell is filled with a non-polar inert gas or is a cavity. The photoelectric detection module includes a long-path absorption cell, into which a mixed gas containing the gas to be measured is continuously introduced. The method includes at least the following steps:

[0110] Step S610: Using the multi-band light source module, multiple discrete band optical signals corresponding to the characteristic absorption peaks of various gases to be tested are emitted sequentially in a time-division manner.

[0111] Step S620: Using the differential filtering modulation module, the reciprocating oscillation of the gas filter disk drives the optical signal corresponding to the gas under test to alternately pass through the reference cell and the measurement cell of the corresponding filter unit in the gas filter disk, thereby differentially modulating the current optical signal to obtain a modulated optical signal; wherein, the portion of the optical signal passing through the reference cell constitutes the reference optical component of the modulated optical signal, and the portion of the optical signal passing through the measurement cell constitutes the measurement optical component of the modulated optical signal; the current oscillation phase of the gas filter disk is detected by the position sensor to generate a synchronization signal, and the synchronization signal is sent to the information processing module;

[0112] Step S630: Using the photoelectric detection module, the modulated optical signal is guided to be absorbed and attenuated by the corresponding gas to be tested in the mixed gas, and then converted into a corresponding electrical signal.

[0113] Step S640: Using the information processing module, based on the synchronization signal, synchronously demodulate the measurement light signal intensity corresponding to the current measurement light component and the reference light signal intensity corresponding to the current reference light component from the electrical signal; based on the measurement light signal intensity and the reference light signal intensity, calculate the current concentration of the gas to be measured, until the concentration detection of multiple gases to be measured is completed.

[0114] In some embodiments, the "multi-band light source module" in step S610 includes a timing drive circuit and an LED light source array; the "LED light source array" includes multiple LED chips that emit different center wavelengths; in step S610, "using the multi-band light source module to sequentially emit optical signals of multiple discrete bands corresponding to the characteristic absorption peaks of multiple gases to be measured" includes:

[0115] Step S6101: Using the timing drive circuit, each LED chip is lit up sequentially according to the synchronization signal to generate and emit multiple discrete wavelength band optical signals in a time-division manner; the timing of lighting up each LED chip coincides with the timing of the corresponding filter unit on the gas filter disk entering the effective area of ​​the optical signal; the emission center wavelength of each LED chip corresponds to the characteristic absorption peak of one of the gases to be measured.

[0116] In some embodiments, step S620, "using the differential filtering modulation module, by reciprocating the gas filter disk, drives the optical signal corresponding to the gas to be measured to alternately pass through the reference cell and the measurement cell of the corresponding filter unit in the gas filter disk, so as to differentially modulate the current optical signal and obtain the modulated optical signal," includes:

[0117] Step S6201: Using the differential filtering modulation module, the high concentration of the gas to be tested filled into the reference cell corresponding to each group of filtering units causes the optical signal passing through the reference cell to be absorbed, thereby obtaining the reference optical component of the modulated optical signal.

[0118] Step S6202: Using the differential filtering modulation module, the intensity of the optical signal corresponding to the measurement cell is maintained by using the non-polar inert gas or cavity in each group of filtering units, thereby obtaining the measurement optical component of the modulated optical signal.

[0119] In some embodiments, the "photoelectric detection module" in step S630 further includes a single-point photoelectric detector; the method further includes:

[0120] Step S6301: Using the photoelectric detection module, guide the modulated optical signal through the long optical path absorption cell, so that the modulated optical signal is absorbed and attenuated to obtain the attenuated optical signal.

[0121] Step S6302: Using the single-point photodetector, the attenuated optical signal is converted into the corresponding electrical signal.

[0122] In some embodiments, step S640, "calculating the current concentration of the gas to be measured based on the measured optical signal intensity and the reference optical signal intensity," includes:

[0123] Step S6401: Using the signal processing module, based on the current measured optical signal intensity and the current reference optical signal intensity, the differential absorption degree corresponding to the current optical signal is obtained through a differential absorption algorithm.

[0124] Step S6402: Use the signal processing module to obtain the preset relationship between concentration and absorbance;

[0125] Step S6403: Using the signal processing module, determine the current concentration of the gas to be measured based on the preset concentration-absorbance relationship and the current differential absorbance.

[0126] It should be noted that the descriptions of the above method embodiments are similar to those of the above device embodiments, and have similar beneficial effects. For technical details not disclosed in the method embodiments of this application, please refer to the descriptions of the device embodiments of this application for understanding.

[0127] It should be noted that, in the embodiments of this application, if the above-described multi-component gas synchronous detection method based on differential filter modulation is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiments of this application, or the part that contributes to related technologies, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause an electronic device to execute all or part of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a magnetic disk, or an optical disk. Thus, the embodiments of this application are not limited to any specific hardware and software combination.

[0128] Correspondingly, embodiments of this application provide a computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the steps in any of the multi-component gas synchronous detection methods based on differential filter modulation described in the above embodiments. Correspondingly, embodiments of this application also provide a computer program product, which, when executed by a processor of an electronic device, is used to implement the steps in any of the multi-component gas synchronous detection methods based on differential filter modulation described in the above embodiments.

[0129] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above-described embodiments are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0130] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0131] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0132] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units; some or all of the units may be selected to achieve the purpose of the embodiments of this application according to actual needs. In addition, each functional unit in the embodiments of this application may be fully integrated into one processing unit, or each unit may be a separate unit, or two or more units may be integrated into one unit; the integrated unit may be implemented in hardware or in the form of hardware plus software functional units.

[0133] Alternatively, if the integrated units described above are implemented as software functional modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, or the parts that contribute to related technologies, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause the device automatic test line to execute all or part of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, ROMs, magnetic disks, or optical disks.

[0134] The methods disclosed in the several method embodiments provided in this application can be arbitrarily combined to obtain new method embodiments without conflict. The features disclosed in the several method or device embodiments provided in this application can be arbitrarily combined to obtain new method embodiments or device embodiments without conflict.

[0135] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A multi-component gas synchronous detection device based on differential filter modulation, characterized in that, The system includes a multi-band light source module, a differential filtering modulation module, a photoelectric detection module, and an information processing module. The differential filtering modulation module includes a gas filter disk and a position sensor. The gas filter disk integrates multiple sets of filtering units. Each set of filtering units includes a reference cell and a measurement cell. Each reference cell is filled with a high concentration of the corresponding gas to be measured, and each measurement cell is filled with a non-polar inert gas or is a cavity. The photoelectric detection module includes a long optical path absorption cell, into which a mixed gas containing the gas to be measured is continuously introduced. The multi-band light source module is used to emit optical signals of multiple discrete bands corresponding to the characteristic absorption peaks of the various gases to be tested in a time-division sequential manner. The differential filtering modulation module is used to drive the optical signal corresponding to the gas under test to alternately pass through the reference cell and the measurement cell of the corresponding filtering unit in the gas filtering disk through the reciprocating oscillation of the gas filtering disk, so as to differentially modulate the current optical signal and obtain a modulated optical signal; wherein, the portion of the optical signal passing through the reference cell constitutes the reference optical component of the modulated optical signal, and the portion of the optical signal passing through the measurement cell constitutes the measurement optical component of the modulated optical signal; the current oscillation phase of the gas filtering disk is detected by the position sensor to generate a synchronization signal, and the synchronization signal is sent to the information processing module; The photoelectric detection module is used to guide the modulated optical signal to be absorbed and attenuated by the corresponding gas to be tested in the mixed gas, and then converted into a corresponding electrical signal. The information processing module is used to synchronously demodulate the measurement light signal intensity corresponding to the current measurement light component and the reference light signal intensity corresponding to the current reference light component from the electrical signal based on the synchronization signal; and to calculate the concentration of the gas to be measured based on the measurement light signal intensity and the reference light signal intensity, until the concentration detection of multiple gases to be measured is completed.

2. The apparatus according to claim 1, characterized in that, The multi-band light source module includes a timing drive circuit, an LED light source array, and a collimating lens group; the LED light source array contains multiple LED chips that emit different center wavelengths. The timing drive circuit is electrically connected to the position sensor; the timing drive circuit illuminates each LED chip sequentially according to the synchronization signal to generate multiple discrete wavelength band optical signals in a time-division sequence; the timing of illuminating each LED chip coincides with the timing of the corresponding filter unit on the gas filter disk entering the effective area of ​​the optical signal; the emission center wavelength of each LED chip corresponds to the characteristic absorption peak of one of the gases to be measured; The collimating lens group is disposed at the optical path output end of each LED chip and is used to collimate the optical signal emitted by the LED chip.

3. The apparatus according to claim 1, characterized in that, The differential filtering modulation module also includes a drive motor and a first optical lens; The drive motor is connected to the gas filter disk, and the drive motor is used to drive the gas filter disk to reciprocate at a fixed angle. Multiple sets of filtering units are integrated on the gas filter disk along its circumference; the reference cell and the measurement cell in each set of filtering units are arranged adjacent to each other; each reference cell is used to absorb the optical signal passing through the reference cell to obtain the reference optical component of the modulated optical signal. Each of the aforementioned measurement cells is used to maintain the intensity of the optical signal passing through the measurement cell, thereby obtaining the measurement optical component of the modulated optical signal; The first optical lens is disposed at the light outlet of the gas filter disk and is used to couple the light signal modulated by the gas filter disk into the photoelectric detection module.

4. The apparatus according to claim 1, characterized in that, The photoelectric detection module also includes: a second optical lens and a single-point photoelectric detector; The long optical path absorption cell is used to absorb and attenuate the modulated optical signal to obtain an attenuated optical signal; the long optical path absorption cell is a White type or a Herriott type multiple reflection cell. The second optical lens is disposed between the output port of the long optical path absorption cell and the single-point photodetector, and is used to converge the attenuated optical signal output from the long optical path absorption cell onto the photosensitive surface of the single-point photodetector. The single-point photodetector is disposed at the output port of the long optical path absorption cell and is used to convert the attenuated optical signal into the electrical signal.

5. The apparatus according to claim 2, characterized in that, The information processing module includes an analog-to-digital conversion acquisition circuit and a processor; The input terminal of the analog-to-digital conversion acquisition circuit is electrically connected to the output terminal of the photoelectric detection module, and is used to acquire the electrical signal output by the photoelectric detection module in real time and convert the electrical signal into a digital signal. The input terminal of the processor is electrically connected to the output terminal of the analog-to-digital conversion acquisition circuit, and is used to receive the corresponding digital signal; The processor's input terminal is electrically connected to the position sensor and is used to receive the synchronization signal to obtain the real-time oscillation phase of the gas filter disk. The processor's output terminal is electrically connected to the timing drive circuit and is used to send control commands to the timing drive circuit to control the time-division lighting sequence of each LED chip. The processor's output is electrically connected to the drive motor and is used to send control signals to the drive motor to control the oscillation frequency and amplitude of the gas filter disk's reciprocating oscillation. The processor is further configured to synchronously demodulate the measurement light signal intensity corresponding to the current measurement light component and the reference light signal intensity corresponding to the current reference light component from the digital signal, and calculate the concentration of the gas to be measured by differential absorption algorithm based on the measurement light signal intensity and the reference light signal intensity.

6. A method for simultaneous detection of multi-component gases based on differential filter modulation, characterized in that, An application is made in a multi-component gas synchronous detection device, the device comprising: a multi-band light source module, a differential filtering modulation module, a photoelectric detection module, and an information processing module; the differential filtering modulation module includes a gas filter disk and a position sensor; the gas filter disk integrates multiple sets of filtering units; each set of filtering units includes a reference cell and a measuring cell, each reference cell being filled with a high concentration of the corresponding analyte gas, and each measuring cell being filled with a non-polar inert gas or being a cavity; the photoelectric detection module includes a long optical path absorption cell, into which a mixed gas containing the analyte gas is continuously introduced; the method includes: Using the multi-band light source module, optical signals of multiple discrete bands corresponding to the characteristic absorption peaks of various gases to be tested are emitted sequentially in a time-division manner. Using the differential filtering modulation module, the reciprocating oscillation of the gas filter disk drives the optical signal corresponding to the gas under test to alternately pass through the reference cell and the measurement cell of the corresponding filter unit in the gas filter disk, thereby differentially modulating the current optical signal to obtain a modulated optical signal. The portion of the optical signal passing through the reference cell constitutes the reference optical component of the modulated optical signal, and the portion of the optical signal passing through the measurement cell constitutes the measurement optical component of the modulated optical signal. The position sensor detects the current oscillation phase of the gas filter disk to generate a synchronization signal, which is then sent to the information processing module. Using the photoelectric detection module, the modulated optical signal is guided to be absorbed and attenuated by the corresponding gas to be tested in the mixed gas, and then converted into a corresponding electrical signal; Using the information processing module, based on the synchronization signal, the intensity of the measured optical signal corresponding to the current measured optical component and the intensity of the reference optical signal corresponding to the current reference optical component are synchronously demodulated from the electrical signal; based on the intensity of the measured optical signal and the intensity of the reference optical signal, the concentration of the gas to be measured is calculated until the concentration detection of multiple gases to be measured is completed.

7. The method according to claim 6, characterized in that, The multi-band light source module includes a timing drive circuit and an LED light source array; the LED light source array contains multiple LED chips that emit different center wavelengths; the method of using the multi-band light source module to sequentially emit optical signals of multiple discrete bands corresponding to the characteristic absorption peaks of various analyte gases includes: Using the timing drive circuit, each LED chip is lit up sequentially according to the synchronization signal to generate and emit multiple discrete wavelength bands of optical signals in a time-division manner; the timing of lighting up each LED chip coincides with the timing of the corresponding filter unit on the gas filter disk entering the effective region of the optical signal; the emission center wavelength of each LED chip corresponds to the characteristic absorption peak of one of the gases to be tested.

8. The method according to claim 6, characterized in that, The method of using the differential filtering modulation module to drive the optical signal corresponding to the gas under test to alternately pass through the reference cell and the measurement cell of the corresponding filtering unit in the gas filtering disk through the reciprocating oscillation of the gas filtering disk, thereby differentially modulating the current optical signal to obtain the modulated optical signal, includes: Using the differential filtering modulation module, the high concentration of the gas to be measured corresponding to the reference cell is filled into each group of filtering units, so that the optical signal passing through the corresponding reference cell is absorbed, and the reference optical component of the modulated optical signal is obtained. By using the differential filtering modulation module, the intensity of the optical signal corresponding to the measurement cell is maintained through the non-polar inert gas or cavity in each group of filtering units, thereby obtaining the measurement optical component of the modulated optical signal.

9. The method according to claim 6, characterized in that, The photoelectric detection module further includes a single-point photoelectric detector; the method further includes: Using the photoelectric detection module, the modulated optical signal is guided through the long optical path absorption cell, so that the modulated optical signal is absorbed and attenuated to obtain an attenuated optical signal. The attenuated optical signal is converted into a corresponding electrical signal using the single-point photodetector.

10. The method according to claim 6, characterized in that, The step of calculating the current concentration of the gas to be measured based on the measured optical signal intensity and the reference optical signal intensity includes: Using the information processing module, based on the current measured optical signal intensity and the current reference optical signal intensity, the differential absorption degree corresponding to the current optical signal is obtained through a differential absorption algorithm; Using the information processing module, a preset relationship between concentration and absorbance is obtained; Using the information processing module, the concentration of the gas to be measured is determined based on the preset concentration-absorbance relationship and the current differential absorbance.

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