An infrared light source modulation method, apparatus, and system for measuring multiple gases.

Abstract

This invention discloses an infrared light source modulation method, apparatus, and system for measuring multiple gases. The method includes: determining the type of gas to be detected; configuring amplitude modulation parameters and PWM modulation parameters according to the gas type; performing amplitude modulation and PWM modulation on the infrared light source to be modulated according to the amplitude modulation parameters and PWM modulation parameters to generate modulated infrared light sources of multiple frequencies; focusing and adjusting the optical paths of the modulated infrared light sources of multiple frequencies and inputting them into a gas chamber to detect multiple gases in the gas chamber. This application, by employing a combined amplitude modulation and PWM modulation method, can split the light source into multiple frequency components to achieve analysis of multiple gas concentrations, improve anti-interference capabilities, and eliminate the need for instrument modification, effectively saving manufacturing costs and reducing manufacturing difficulty.

Description

Technical Field

[0001] This invention relates to the field of gas analysis technology, and in particular to an infrared light source modulation method, apparatus, and system capable of measuring multiple gases. Background Technology

[0002] NDIR (Non-Dispersive Infrared) is a technique that measures the absorption of infrared spectra by specific gases. By selecting an appropriate infrared wavelength and optical path design, when infrared light passes through the analyte gas in the gas chamber, if the gas absorbs the infrared light, the detector detects a change in the intensity of the light signal. This change in signal intensity is proportional to the concentration of the gas in the sample. The optical detector inside the NDIR sensor converts the change in optical signal intensity into a readable electrical signal, thereby detecting the concentration of the analyte gas. Because of various light sources and noise interference in the environment, these interfering signals may be incorrectly identified as signals absorbed by the sample. However, by modulating the infrared light source, the signal absorbed by the sample can be effectively distinguished from other interference signals, thereby improving the sensitivity and stability of the sensor.

[0003] However, because various gases absorb infrared radiation to varying degrees, NDIR sensors often only measure single gases. For multi-component gas measurements, cross-interference between gases affects accuracy. While existing gas analyzers for multi-component gas measurements often employ sensors with different measurement principles, this increases manufacturing costs and instrument size due to the complexity of the gas path. Alternatively, increasing the number of internal filters in the NDIR sensor to measure infrared intensity at different wavelengths can achieve the goal of detecting multiple gases, but this also increases sensor manufacturing costs and complexity. Summary of the Invention

[0004] Therefore, it is necessary to provide an infrared light source modulation method, device, system, and storage medium capable of measuring multiple gases to address the aforementioned technical problems, thereby solving the issues of high manufacturing costs and significant manufacturing difficulties in the existing technology.

[0005] This application is implemented as follows: Firstly, it provides an infrared light source modulation method for measuring multiple gases, the method comprising:

[0006] Determine the type of gas to be detected;

[0007] Configure amplitude modulation parameters and PWM modulation parameters according to the type of gas to be detected;

[0008] Based on the amplitude modulation parameters and PWM modulation parameters, the infrared light source to be modulated is subjected to amplitude modulation and PWM modulation to generate modulated infrared light sources of multiple frequencies.

[0009] The optical path of the modulated infrared light source of the multiple frequencies is focused and adjusted, and then input into the gas chamber to detect the multiple gases in the gas chamber through the modulated infrared light source of the multiple frequencies.

[0010] In one embodiment, the step of performing amplitude modulation and PWM modulation on the infrared light source to be modulated based on the amplitude modulation parameters and PWM modulation parameters includes:

[0011] Based on the amplitude modulation parameters, a first modulation algorithm is determined;

[0012] Based on the PWM modulation parameters, determine the second modulation algorithm;

[0013] The first modulation algorithm and the second modulation algorithm are combined to generate a combined modulation algorithm, which is used to perform amplitude modulation and PWM modulation on the modulated infrared light source.

[0014] In one embodiment, the step of performing amplitude modulation and PWM modulation on the infrared light source to be modulated according to the amplitude modulation parameters and PWM modulation parameters to generate a modulated infrared light source of multiple frequencies includes:

[0015] The amplitude of the infrared light source to be modulated is modulated according to the amplitude modulation parameters.

[0016] Based on the PWM modulation parameters, pulse width modulation is applied to the amplitude-modulated infrared light source.

[0017] In one embodiment, the first modulation algorithm is expressed as:

[0018] S(t) = A c [1+mcos(2πf m t)]cos(2πf c t);

[0019] Where S(t) represents the modulated signal, A c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c This indicates the frequency of the carrier signal.

[0020] In one embodiment, the second modulation algorithm is expressed as:

[0021]

[0022] Where fPWM T represents the frequency of the PWM signal. PWM This indicates the period of the PWM signal.

[0023] In one embodiment, the combined modulation algorithm is expressed as:

[0024] S(t) = A c [1+mcos(2πf m t)]cos(2πf c t)×PWM(t);

[0025] Where S(t) represents the modulated signal, PWM(t) represents the value of the PWM signal at time t, and A c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c This indicates the frequency of the carrier signal.

[0026] In one embodiment, the modulated infrared light source with multiple frequencies is represented by the following formula:

[0027]

[0028] Where S(t) represents the modulated signal, PWM(t) represents the value of the PWM signal at time t, and tA c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c f represents the frequency of the carrier signal. c +f m and f c -f m This indicates the frequencies of the upper and lower sidebands.

[0029] Secondly, an infrared light source modulation device capable of measuring multiple gases is provided, comprising:

[0030] Gas type determination unit, used to determine the type of gas to be detected;

[0031] The parameter configuration unit is used to configure the amplitude modulation parameters and PWM modulation parameters according to the type of gas to be detected;

[0032] An infrared light source modulation unit is used to perform amplitude modulation and PWM modulation on the infrared light source to be modulated according to the amplitude modulation parameters and PWM modulation parameters, so as to generate a modulated infrared light source with multiple frequencies.

[0033] The optical path focusing adjustment unit is used to adjust the focusing of the optical path of the modulated infrared light source of the multiple frequencies and then input it into the gas chamber so as to detect the multiple gases in the gas chamber through the modulated infrared light source of the multiple frequencies.

[0034] In one embodiment, the infrared light source modulation unit is further configured to:

[0035] Based on the amplitude modulation parameters, a first modulation algorithm is determined;

[0036] Based on the PWM modulation parameters, determine the second modulation algorithm;

[0037] The first modulation algorithm and the second modulation algorithm are combined to generate a combined modulation algorithm, which is used to perform amplitude modulation and PWM modulation on the modulated infrared light source.

[0038] Thirdly, an infrared light source modulation system capable of measuring multiple gases is provided, including:

[0039] Infrared light source emitter;

[0040] The infrared light source modulation device inside the NDIR sensor that can measure multiple gases, as described above, is used to perform a combination modulation of amplitude and PWM on the infrared light source emitted by the infrared light source emitter.

[0041] An infrared detector is used to receive modulated infrared light after it passes through the air chamber;

[0042] A bandpass filter circuit is used to filter the modulated infrared light source received by the infrared detector.

[0043] The demodulation circuit is used to demodulate the filtered modulated infrared light source.

[0044] The control and computing unit is used for gas analysis based on the demodulated infrared light source.

[0045] The aforementioned method, apparatus, system, and storage medium for measuring multiple gases using an infrared light source modulation method include: determining the type of gas to be detected; configuring amplitude modulation parameters and PWM modulation parameters according to the type of gas to be detected; performing amplitude modulation and PWM modulation on the infrared light source to be modulated according to the amplitude modulation parameters and PWM modulation parameters to generate modulated infrared light sources of multiple frequencies; adjusting the focusing of the optical path of the modulated infrared light sources of multiple frequencies, and inputting them into a gas chamber to detect multiple gases in the gas chamber using the modulated infrared light sources of multiple frequencies. This application, by employing a combined modulation method of amplitude modulation and PWM modulation, can split the light source into multiple frequency components to achieve the analysis of multiple gases, increase sensor sensitivity, and shift the frequency of the useful signal away from the frequency range of the interference signal to improve anti-interference capability. Furthermore, it eliminates the need for instrument modification, effectively saving manufacturing costs and reducing manufacturing difficulty. Attached Figure Description

[0046] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a schematic flowchart of an infrared light source modulation method for measuring multiple gases in one embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram of an infrared light source modulation device capable of measuring multiple gases according to an embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of an infrared light source modulation system capable of measuring multiple gases according to an embodiment of the present invention. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] In one embodiment, such as Figure 1 As shown, an infrared light source modulation method for measuring multiple gases is provided, which can be applied to NDIR sensors, and specifically includes the following steps:

[0052] In step S110, the type of gas to be detected is determined;

[0053] In the embodiments of this application, the gas type may include sulfur dioxide, carbon dioxide, methane, oxygen, carbon monoxide, hydrogen, etc.

[0054] In the embodiments of this application, the type of gas to be detected can be determined according to the function and purpose of the gas analyzer. For example, when performing coal gas analysis, the type of gas to be detected can be carbon dioxide, oxygen, carbon monoxide, hydrogen, etc.

[0055] In one implementation method, the type of gas to be detected can be the gas that needs to be detected, which is input by the user, or it can be the type of gas determined according to the purpose of detection.

[0056] In step S120, amplitude modulation parameters and PWM modulation parameters are configured according to the type of gas to be detected;

[0057] In this embodiment, the amplitude modulation parameter may include the oscillation frequency and the amplitude, and the PWM modulation parameter may include the duty cycle and the PWM frequency.

[0058] In the embodiments of this application, the modulation parameters corresponding to different modulation methods can be determined according to different gas types. Taking amplitude modulation parameters as an example, the oscillation frequency is generally selected in the range of several hundred Hz to several kHz. When measuring CO2, the amplitude frequency can be set to 1 kHz. The amplitude setting can be further adjusted according to the specific sensor and detection environment. If the amplitude setting is too small, it will result in a weak signal, low signal-to-noise ratio, and low measurement accuracy. If the amplitude setting is too large, it will cause sensor saturation, thus affecting the measurement accuracy. Therefore, it is necessary to conduct repeated experiments to find the optimal amplitude size. For example, taking CO2 measurement as an example, the amplitude range that can be used is between 1% and 5%.

[0059] Taking PWM modulation parameters as an example, the duty cycle refers to the proportion of the PWM signal's high-level duration to the entire cycle, which can be achieved by adjusting the PWM control chip. The PWM frequency is generally selected within the range of tens to hundreds of Hz. When measuring CO2, the PWM frequency can be set to 1kHz. Higher PWM frequencies result in faster sensor response but also increase power consumption and noise, affecting the signal-to-noise ratio (SNR); conversely, lower PWM frequencies result in slower response but reduce power consumption and noise. Therefore, when setting the PWM frequency, it is necessary to further balance various factors such as sensor response speed, SNR, power consumption, and interference.

[0060] In step S130, the amplitude modulation parameters and PWM modulation parameters are used to perform amplitude modulation and PWM modulation on the infrared light source to be modulated in order to generate a modulated infrared light source with multiple frequencies.

[0061] In one embodiment of this application, constructing a combined modulation algorithm based on the amplitude modulation parameters and the PWM modulation parameters includes:

[0062] Based on the amplitude modulation parameters, a first modulation algorithm is determined;

[0063] Based on the PWM modulation parameters, determine the second modulation algorithm;

[0064] The first modulation algorithm and the second modulation algorithm are combined to generate the combined modulation algorithm.

[0065] Specifically, based on the amplitude modulation parameters, the first modulation algorithm can be expressed as:

[0066] S(t) = A c [1+mcos(2πf m t)]cos(2πf c t);

[0067] Where S(t) represents the modulated signal, A c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c This indicates the frequency of the carrier signal.

[0068] Furthermore, based on the PWM modulation parameters, the second modulation algorithm can be expressed as:

[0069]

[0070] Where f PWM T represents the frequency of the PWM signal. PWM This indicates the period of the PWM signal.

[0071] Furthermore, based on the first modulation algorithm and the second modulation algorithm, the first modulation algorithm and the second modulation algorithm are multiplied together to form the combined modulation algorithm, which can be specifically expressed as:

[0072] S(t) = A c [1+mcos(2πf m t)]cos(2πf c t)×PWM(t);

[0073] Where PWM(t) represents the value of the PWM signal at time t, A c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c This indicates the frequency of the carrier signal.

[0074] In this embodiment of the application, the infrared light source can be divided into multiple frequency components according to the above-described combined modulation algorithm, as shown below:

[0075]

[0076] Among them, f c Represented as carrier frequency, f c -f m and f c +f m This is represented as the upper and lower sideband frequencies.

[0077] As can be seen from the above formula, by combining PWM modulation and AM modulation, three frequency components can be generated: carrier frequency, upper and lower sideband frequencies, and by selecting the carrier frequency, three different gas concentrations can be detected by infrared light sources of these three frequencies.

[0078] This can be understood as follows: by combining modulation algorithms, three peaks can be generated at the three frequencies mentioned above. These three peaks can be used to detect three gases. Conversely, based on the known frequency characteristics of the three gases, by using appropriate carrier frequency and PWM frequency, these three frequencies can be modulated. Since different gases absorb infrared light sources of different frequencies to different degrees, the gas concentration of the three gases can be detected.

[0079] In one embodiment of this application, the step of performing amplitude modulation and PWM modulation on the infrared light source to be modulated according to the amplitude modulation parameters and PWM modulation parameters to generate a modulated infrared light source of multiple frequencies includes:

[0080] The amplitude of the infrared light source to be modulated is modulated according to the amplitude modulation parameters.

[0081] Based on the PWM modulation parameters, pulse width modulation is applied to the amplitude-modulated infrared light source.

[0082] Understandably, when performing amplitude modulation and PWM modulation combined modulation on an infrared light source to be modulated, amplitude modulation can be performed first, followed by PWM modulation, in order to improve signal stability and anti-interference capability.

[0083] Furthermore, a combined modulation method of amplitude modulation and PWM is employed. Before amplitude modulation, a suitable oscillation circuit needs to be constructed, which can be an RC circuit, LC circuit, crystal oscillator circuit, or other similar circuits. Since RC and LC circuits have relatively low accuracy, this application prioritizes the use of a crystal oscillator circuit to improve accuracy. After constructing the suitable oscillation circuit, the oscillation frequency and amplitude can be configured according to the gas type to perform amplitude modulation of the infrared light source to be detected.

[0084] When performing PWM modulation, an appropriate PWM control chip can be selected, such as NE555 or ATtiny. Preferably, NE555 is used as the PWM control chip. Once an appropriate PWM control chip is selected, the duty cycle and PWM frequency can be configured to perform PWM modulation on the amplitude-modulated infrared light source.

[0085] In this embodiment of the application, the combined modulation algorithm can perform mixed modulation of amplitude modulation and PWM modulation on the infrared light source to be modulated, and at the same time, the infrared light source to be modulated can be split into multiple frequencies. By modulating the infrared light source with multiple frequencies, since the type of gas to be detected is known, and different gas types have different absorption characteristics to infrared light sources of different frequencies, it is possible to detect the concentration of multiple gases.

[0086] In this embodiment, the above-described combined modulation algorithm is used to modulate the infrared light source. The modulated signals are all within a preset frequency range. Since the frequency of the interference signal is far from the preset frequency range of the carrier frequency signal and the modulation signal, the power of the interference signal will be filtered out by the subsequent filter. Alternatively, the carrier signal can shift the frequency of the useful signal away from the frequency range of the interference signal, thereby effectively improving the anti-interference capability. Specifically, it can be shown in the following formula:

[0087] S(t) = A c [1+mcos(2πf m t)]cos(2πf c t)×PWM(t)+n(t)

[0088] Where n(t) represents the interference signal.

[0089] In step S140, after focusing and adjusting the optical path of the modulated infrared light source of the multiple frequencies, the light is input into the gas chamber so as to detect the multiple gases in the gas chamber by means of the modulated infrared light source of the multiple frequencies.

[0090] In this embodiment, the infrared light source to be modulated, after amplitude modulation and pulse width modulation, can form a rectangular wave signal whose duty cycle and amplitude both vary with time. The optical path of this rectangular wave signal can be focused and adjusted to ensure the stability and consistency of the light.

[0091] Among these, optical components such as reflectors can be used to achieve focusing and adjustment of the optical path.

[0092] This application provides a method for modulating an infrared light source capable of measuring multiple gases, comprising: determining the type of gas to be detected; configuring amplitude modulation parameters and PWM modulation parameters according to the type of gas to be detected; performing amplitude modulation and PWM modulation on the infrared light source to be modulated according to the amplitude modulation parameters and PWM modulation parameters to generate modulated infrared light sources of multiple frequencies; adjusting the focusing of the optical path of the modulated infrared light sources of multiple frequencies, and inputting them into a gas chamber to detect multiple gases in the gas chamber through the modulated infrared light sources of multiple frequencies. This application, by employing a combined modulation method of amplitude modulation and PWM modulation, can split the light source into multiple frequency components to achieve the analysis of multiple gases, increase sensor sensitivity, and shift the frequency of the useful signal away from the frequency range of the interference signal to improve anti-interference capability. Furthermore, it eliminates the need for instrument modification, effectively saving manufacturing costs and reducing manufacturing difficulty.

[0093] It should be understood that the sequence number of each step in the above embodiments does not imply the 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 the present invention.

[0094] In one embodiment, an infrared light source modulation device capable of measuring multiple gases is provided, which corresponds one-to-one with the infrared light source modulation method capable of measuring multiple gases described in the above embodiments. For example... Figure 2 As shown, the infrared light source modulation device capable of measuring multiple gases includes a gas type determination unit 10, a parameter configuration unit 20, an infrared light source modulation unit 30, and an optical path focusing adjustment unit 40. Detailed descriptions of each functional module are as follows:

[0095] Gas type determination unit 10 is used to determine the type of gas to be detected;

[0096] The parameter configuration unit 20 is used to configure the amplitude modulation parameters and PWM modulation parameters according to the type of gas to be detected;

[0097] The infrared light source modulation unit 30 is used to perform amplitude modulation and PWM modulation on the infrared light source to be modulated according to the amplitude modulation parameters and PWM modulation parameters, so as to generate a modulated infrared light source with multiple frequencies.

[0098] The optical path focusing adjustment unit 40 is used to adjust the focusing of the optical path of the modulated infrared light source of the multiple frequencies and then input it into the gas chamber so as to detect the multiple gases in the gas chamber through the modulated infrared light source of the multiple frequencies.

[0099] In one embodiment, the infrared light source modulation unit 30 is further configured to:

[0100] Based on the amplitude modulation parameters, a first modulation algorithm is determined;

[0101] Based on the PWM modulation parameters, determine the second modulation algorithm;

[0102] The first modulation algorithm and the second modulation algorithm are combined to generate the combined modulation algorithm.

[0103] In one embodiment, the infrared light source modulation unit 30 is further configured to:

[0104] The amplitude of the infrared light source to be modulated is modulated according to the amplitude modulation parameters.

[0105] Based on the PWM modulation parameters, pulse width modulation is applied to the amplitude-modulated infrared light source.

[0106] In one embodiment, the infrared light source modulation unit 40 is further configured to:

[0107] The infrared light source to be modulated is amplitude modulated according to the first modulation algorithm;

[0108] The amplitude-modulated infrared light source is pulse-width modulated according to the second modulation algorithm.

[0109] In one embodiment, the first modulation algorithm is expressed as:

[0110] S(t) = A c [1+mcos(2πf m t)]cos(2πf c t);

[0111] Where S(t) represents the modulated signal, A c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c This indicates the frequency of the carrier signal.

[0112] In one embodiment, the second modulation algorithm is expressed as:

[0113]

[0114] Where f PWM T represents the frequency of the PWM signal. PWM This indicates the period of the PWM signal.

[0115] In one embodiment, the combined modulation algorithm is expressed as:

[0116] S(t) = A c [1+mcos(2πf m t)]cos(2πfc t)×PWM(t);

[0117] Where PWM(t) represents the value of the PWM signal at time t, A c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c This indicates the frequency of the carrier signal.

[0118] The modulated infrared light source with multiple frequencies is represented by the following formula:

[0119]

[0120] Where S(t) represents the modulated signal, PWM(t) represents the value of the PWM signal at time t, and tA c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c f represents the frequency of the carrier signal. c +f m and f c -f m This indicates the frequencies of the upper and lower sidebands.

[0121] This application employs a combined modulation method of amplitude modulation and PWM modulation, which can split the light source into multiple frequency components to achieve the analysis of multiple gases, increase sensor sensitivity, and shift the frequency of the useful signal away from the frequency range of the interference signal to improve anti-interference capability. Moreover, it does not require modification of the instrument, which can effectively save manufacturing costs and reduce manufacturing difficulty.

[0122] Specific limitations regarding the infrared light source modulation device capable of measuring multiple gases can be found in the limitations of the infrared light source modulation method capable of measuring multiple gases described above, and will not be repeated here. Each module in the aforementioned infrared light source modulation device capable of measuring multiple gases can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0123] In one embodiment, an infrared light source modulation system capable of measuring multiple gases is provided, comprising the aforementioned infrared light source modulation device capable of measuring multiple gases. Figure 3 As shown, the infrared light source modulation system capable of measuring multiple gases includes:

[0124] Infrared light source emitter;

[0125] The infrared light source modulation device inside the NDIR sensor that can measure multiple gases, as described above, is used to perform a combination modulation of amplitude and PWM on the infrared light source emitted by the infrared light source emitter.

[0126] An infrared detector is used to receive modulated infrared light after it passes through the air chamber;

[0127] A bandpass filter circuit is used to filter the modulated infrared light source received by the infrared detector.

[0128] The demodulation circuit is used to demodulate the filtered modulated infrared light source.

[0129] The control and computing unit is used for gas analysis based on the demodulated infrared light source.

[0130] In this embodiment, an infrared light source to be modulated is emitted by an infrared light source emitter. Then, the infrared light source is combined and modulated by a preset AM modulation circuit and a PWM modulation circuit. The modulated infrared light source is then focused and adjusted by a reflective element before being input into a gas chamber containing a gas to be detected. When the modulated infrared light source passes through the gas to be detected, it can be received by an infrared detector. After photoelectric conversion by the infrared detector, an electrical signal is obtained. The electrical signal is then filtered by a bandpass filter circuit to remove interference signals. Then, it is demodulated by a demodulation circuit. Finally, the gas concentration is analyzed by a control and calculation unit.

[0131] In one embodiment of this application, when performing mixed modulation of amplitude modulation and PWM modulation on the infrared light source to be modulated, amplitude modulation is performed first, and then PWM modulation is performed.

[0132] This application employs a combined modulation method of amplitude modulation and PWM modulation, which can split the light source into multiple frequency components to achieve the analysis of multiple gases, increase sensor sensitivity, and shift the frequency of the useful signal away from the frequency range of the interference signal to improve anti-interference capability. Moreover, it does not require modification of the instrument, which can effectively save manufacturing costs and reduce manufacturing difficulty.

[0133] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0134] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for modulating an infrared light source capable of measuring multiple gases, characterized in that, The method includes: Determine the type of gas to be detected; Based on the type of gas to be detected, configure amplitude modulation parameters and PWM modulation parameters, wherein the amplitude modulation parameters include oscillation frequency and amplitude, and the PWM modulation parameters include duty cycle and PWM frequency; A first modulation algorithm is determined based on the amplitude modulation parameters, and the first modulation algorithm is expressed as follows: S(t)=A c [1+mcos(2πf m t)]cos(2πf c t); Where S(t) represents the modulated signal, A c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c Indicates the frequency of the carrier signal; Based on the PWM modulation parameters, a second modulation algorithm is determined, which is expressed as follows: Where f PWM T represents the frequency of the PWM signal. PWM Indicates the period of the PWM signal; The first modulation algorithm and the second modulation algorithm are combined to generate a combined modulation algorithm, which is expressed as follows: The combined modulation algorithm is expressed as follows: S(t)=A c [1+mcos(2πf m t)]cos(2πf c t)×PWM(t); Where S(t) represents the modulated signal, PWM(t) represents the value of the PWM signal at time t, and A c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c Indicates the frequency of the carrier signal; The combined modulation algorithm is used to perform amplitude modulation and PWM modulation on the infrared light source to be modulated, generating modulated infrared light sources of multiple frequencies. The modulated infrared light sources of multiple frequencies are represented by the following formula: Where S(t) represents the modulated signal, PWM(t) represents the value of the PWM signal at time t, and tA c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c f represents the frequency of the carrier signal. c +f m and f c -f m Indicates the frequencies of the upper and lower sidebands; After focusing and adjusting the optical path of the modulated infrared light source of the multiple frequencies using a reflector, the light is input into the gas chamber to detect the multiple gases in the gas chamber through the modulated infrared light source of the multiple frequencies.

2. The infrared light source modulation method for measuring multiple gases as described in claim 1, characterized in that, The step of performing amplitude modulation and PWM modulation on the infrared light source to be modulated according to the amplitude modulation parameters and PWM modulation parameters to generate modulated infrared light sources of multiple frequencies includes: The amplitude of the infrared light source to be modulated is modulated according to the amplitude modulation parameters. Based on the PWM modulation parameters, pulse width modulation is applied to the amplitude-modulated infrared light source.

3. An infrared light source modulation device capable of measuring multiple gases, characterized in that, The device includes: Gas type determination unit, used to determine the type of gas to be detected; The parameter configuration unit is used to configure amplitude modulation parameters and PWM modulation parameters according to the type of gas to be detected, wherein the amplitude modulation parameters include oscillation frequency and amplitude, and the PWM modulation parameters include duty cycle and PWM frequency; An infrared light source modulation unit is used to determine a first modulation algorithm based on the amplitude modulation parameters, wherein the first modulation algorithm is expressed as follows: S(t)=A c [1+mcos(2πf m t)]cos(2πf c t); Where S(t) represents the modulated signal, A c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c Indicates the frequency of the carrier signal; Based on the PWM modulation parameters, a second modulation algorithm is determined, which is expressed as follows: Where f PWM T represents the frequency of the PWM signal. PWM Indicates the period of the PWM signal; The first modulation algorithm and the second modulation algorithm are combined to generate a combined modulation algorithm, which is expressed as follows: The combined modulation algorithm is expressed as follows: S(t)=A c [1+mcos(2πf m t)]cos(2πf c t)×PWM(t); Where S(t) represents the modulated signal, PWM(t) represents the value of the PWM signal at time t, and A c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c Indicates the frequency of the carrier signal; The combined modulation algorithm is used to perform amplitude modulation and PWM modulation on the infrared light source to be modulated, generating modulated infrared light sources of multiple frequencies. The modulated infrared light sources of multiple frequencies are represented by the following formula: Where S(t) represents the modulated signal, PWM(t) represents the value of the PWM signal at time t, and tA c The amplitude of the carrier signal is represented by m, the modulation depth is represented by f. m f represents the frequency of the modulating signal. c f represents the frequency of the carrier signal. c +f m and f c -f m Indicates the frequencies of the upper and lower sidebands; The optical path focusing adjustment unit is used to focus and adjust the optical path of the modulated infrared light source of the multiple frequencies using a reflector, and then input it into the gas chamber so as to detect the multiple gases in the gas chamber through the modulated infrared light source of the multiple frequencies.

4. An infrared light source modulation system capable of measuring multiple gases, characterized in that, The system includes: Infrared light source emitter; The infrared light source modulation device for measuring multiple gases as described in claim 3 is used to perform amplitude and PWM combined modulation on the infrared light source emitted by the infrared light source emitter; An infrared detector is used to receive modulated infrared light after it passes through the air chamber; A bandpass filter circuit is used to filter the modulated infrared light source received by the infrared detector. The demodulation circuit is used to demodulate the filtered modulated infrared light source. The control and computing unit is used for gas analysis based on the demodulated infrared light source.

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