Signal processing circuit and method for gas measurement, electronic equipment and storage medium
By combining operational amplifier circuits, sample-and-hold circuits, and differential circuits, the problems of light source power and beam cutter structure in gas measurement were solved, effectively removing background noise and ensuring the accuracy and stability of gas measurement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HANGZHOU CHUNLAI TECH
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-21
AI Technical Summary
Existing gas measurement signal processing circuits require low-power light sources when the optical path is short and the absorbance of the gas being measured is high, which leads to a longer response time. Furthermore, the cutter wheel structure cannot effectively distinguish between different measurement components, and the filters have mutual interference problems.
The signal processing circuit, composed of an operational amplifier circuit, a sample-and-hold circuit, and a differential circuit, separates the reference signal and the measurement signal, performs sample-and-hold operations on each, and uses the differential circuit to remove background slow-varying noise interference.
It effectively eliminates the influence of slowly varying background noise, ensuring the accuracy and stability of gas measurements and improving the precision and reliability of measurements.
Smart Images
Figure CN121899050A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of signal processing circuit technology, and relates to a signal processing circuit, and more particularly to a signal processing circuit, method, electronic device and storage medium for gas measurement. Background Technology
[0002] The signal processing circuit for gas measurement using the GFC method is located at the end of the GFC gas analyzer. The front-end components include a light source, a gas chamber, a light cutter wheel, and a detector. Two gas chambers are mounted on the light cutter wheel, and each gas chamber has several light-transmitting holes. During the rotation of the motor, light passes through the light-transmitting holes sequentially in the direction of motor rotation and forms an induced voltage on the detector.
[0003] The beam cutter is divided into two equal parts along its central axis. One part is filled with the gas to be tested at a certain concentration, and the other part is filled with a standard gas that does not absorb the gas to be tested. Each of these two parts is further divided, with four light-transmitting holes placed in each part. When the beam cutter rotates once, the signals generated at the detector end are arranged in chronological order as follows: four low-amplitude reference signal square waves and four high-amplitude measurement signal square waves.
[0004] When the optical path is short and the absorbance of the gas being measured is strong, the required power of the light source is generally smaller. In this case, the signal can be modulated by switching the light source on and off, meaning that a mechanical structure such as a light cutter wheel is not needed.
[0005] The light cutter wheel is used in situations where the optical path is long, the absorbance of the gas being measured is weak, and the power of the light source is high. It is generally a silicon carbide rod with a power of 10W or more. Infrared light generally comes from the thermal effect. Therefore, the response time of these high-power infrared light sources will be lengthened due to heating and cooling. Furthermore, the stable dispersion of infrared light also requires stable heating. Therefore, it is impossible to modulate the light through the light source.
[0006] In addition, some scissor-shaped solutions use filters to distinguish different measurement components. The disadvantage is that some absorption peaks of the gas to be measured may interfere with each other, and the filters cannot completely distinguish them.
[0007] In view of this, there is an urgent need to design a new signal processing circuit in order to overcome at least some of the aforementioned defects of existing signal processing circuits. Summary of the Invention
[0008] This invention provides a signal processing circuit, method, electronic device, and storage medium for gas measurement, which can eliminate the influence of slowly varying background noise and ensure accurate and stable measurement.
[0009] To solve the above-mentioned technical problems, according to one aspect of the present invention, the following technical solution is adopted:
[0010] A signal processing circuit for gas measurement, the signal processing circuit comprising: an operational amplifier circuit, a sample-and-hold circuit, a first differential circuit, and a second differential circuit;
[0011] The operational amplifier circuit is connected to the sample-and-hold circuit, and the sample-and-hold circuit is connected to the first differential circuit and the second differential circuit respectively;
[0012] The operational amplifier circuit is used to receive the detection signal and amplify the detection signal;
[0013] The sample-and-hold circuit is used to separate the reference signal and the measurement signal in the detection signal, and to sample and hold the high-level signal and the low-level signal in the reference signal, and to sample and hold the high-level signal and the low-level signal in the measurement signal.
[0014] The first differential circuit is used to subtract the high-level signal in the reference signal output by the sample-and-hold circuit from the low-level signal in the reference signal to obtain the reference signal while removing the interference of background slow-varying noise.
[0015] The second differential circuit is used to subtract the high-level signal from the measurement signal output by the sample-and-hold circuit from the low-level signal in the measurement signal, thereby obtaining the measurement signal while removing the interference of background slow-varying noise.
[0016] In one embodiment of the present invention, the sample-and-hold circuit includes a second comparator U2, a second capacitor C2, a fourth capacitor C4, a sixth capacitor C6, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a ninth resistor R9.
[0017] The second terminal of the second capacitor C2 is connected to the first terminal of the fifth resistor R5. The second terminal of the fifth resistor R5 is connected to the second terminal of the fourth resistor R4 and the non-inverting input terminal of the second comparator U2. The first terminal of the fourth resistor R4 is grounded.
[0018] The inverting input of the second comparator U2 is connected to the second terminal of the seventh resistor R7, the first terminal of the ninth resistor R9, and the first terminal of the sixth capacitor C6, respectively. The first terminal of the seventh resistor R7 is grounded.
[0019] The output of the second comparator U2 is connected to the second terminal of the ninth resistor R9, the second terminal of the sixth capacitor C6, and the first terminal of the sixth resistor R6, respectively; the second terminal of the sixth resistor R6 is connected to the first terminal of the fourth capacitor C4.
[0020] In one embodiment of the present invention, the sample-and-hold circuit includes a first reference signal sample-and-hold circuit, a second reference signal sample-and-hold circuit, a first measurement signal sample-and-hold circuit, and a second measurement signal sample-and-hold circuit.
[0021] The operational amplifier circuit is connected to the first reference signal sample and hold circuit, the second reference signal sample and hold circuit, the first measurement signal sample and hold circuit, and the second measurement signal sample and hold circuit, respectively.
[0022] The first reference signal sample-and-hold circuit and the second reference signal sample-and-hold circuit are connected to the first differential circuit, and the first measurement signal sample-and-hold circuit and the second measurement signal sample-and-hold circuit are respectively connected to the second differential circuit;
[0023] The first reference signal sample and hold circuit is used to sample and hold the positive level signal in the reference signal, and the second reference signal sample and hold circuit is used to sample and hold the negative level signal in the reference signal;
[0024] The first measurement signal sample-and-hold circuit is used to sample and hold the positive level signal in the measurement signal, and the second measurement signal sample-and-hold circuit is used to sample and hold the negative level signal in the measurement signal.
[0025] In one embodiment of the present invention, the first reference signal sample and hold circuit includes a first switch S1, a first resistor R1, and a first capacitor C1; the first end of the first switch S1 is connected to the operational amplifier circuit, the second end of the first switch S1 is connected to the first end of the first resistor R1, the second end of the first resistor R1 is connected to the second end of the first capacitor C1, and the first end of the first capacitor C1 is grounded.
[0026] The second reference signal sample and hold circuit includes a second switch S2, a second resistor R2, and a third capacitor C3; the first end of the second switch S2 is connected to the operational amplifier circuit, the second end of the second switch S2 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the second end of the third capacitor C3, and the first end of the third capacitor C3 is grounded.
[0027] The first measurement signal sampling and holding circuit includes a third switch S3, an eighth resistor R8, and a fifth capacitor C5; the first end of the third switch S3 is connected to the operational amplifier circuit, the second end of the third switch S3 is connected to the first end of the eighth resistor R8, the second end of the eighth resistor R8 is connected to the second end of the fifth capacitor C5, and the first end of the fifth capacitor C5 is grounded.
[0028] The second measurement signal sampling and holding circuit includes a fourth switch S4, a first zero resistor R10, and a seventh capacitor C7; the first end of the fourth switch S4 is connected to the operational amplifier circuit, the second end of the fourth switch S4 is connected to the first end of the first zero resistor R10, the second end of the first zero resistor R10 is connected to the second end of the seventh capacitor C7, and the first end of the seventh capacitor C7 is grounded.
[0029] In one embodiment of the present invention, the first differential circuit includes a first instrumentation amplifier U1 and a third resistor R3; the non-inverting input terminal of the first instrumentation amplifier U1 is connected to the second terminal of the first resistor R1, and the inverting input terminal of the first instrumentation amplifier U1 is connected to the second terminal of the second resistor R2; the RO port of the first instrumentation amplifier U1 is connected to the first terminal of the third resistor R3, and the RG port of the first instrumentation amplifier U1 is connected to the second terminal of the third resistor R3.
[0030] The second differential circuit includes a third instrumentation amplifier U3 and a first resistor R11; the non-inverting input terminal of the third instrumentation amplifier U3 is connected to the second terminal of the eighth resistor R8, and the inverting input terminal of the third instrumentation amplifier U3 is connected to the second terminal of the first zero resistor R10; the RO port of the third instrumentation amplifier U3 is connected to the first terminal of the first resistor R11, and the RG port of the third instrumentation amplifier U3 is connected to the second terminal of the first resistor R11.
[0031] According to another aspect of the present invention, the following technical solution is adopted: a signal processing method for the above-mentioned signal processing circuit for gas measurement, the signal processing method comprising:
[0032] The operational amplifier circuit receives the detection signal and amplifies it;
[0033] The sample-and-hold circuit separates the reference signal and the measurement signal in the detection signal, and samples and holds the high-level signal and the low-level signal in the reference signal, and samples and holds the high-level signal and the low-level signal in the measurement signal, respectively.
[0034] The first differential circuit subtracts the high-level signal from the reference signal output by the sample-and-hold circuit from the low-level signal in the reference signal to obtain the reference signal while removing the interference of slowly varying background noise.
[0035] The second differential circuit subtracts the high-level signal from the sample-and-hold circuit's output measurement signal from the low-level signal in the measurement signal, obtaining the measurement signal while removing background slow-varying noise interference.
[0036] According to another aspect of the present invention, the following technical solution is adopted: an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above method.
[0037] According to another aspect of the present invention, the following technical solution is adopted: a storage medium storing computer program instructions thereon, which, when executed by a processor, implement the steps of the above-described method.
[0038] The beneficial effects of the present invention are as follows: the signal processing circuit, method, electronic device and storage medium for gas measurement proposed in the present invention can eliminate the influence of background slow-varying noise, and extract the signal from the periodically interleaved reference and measurement signals respectively, and divide it into two channels for ADC to collect, so as to ensure the accuracy and stability of the measurement. Attached Figure Description
[0039] Figure 1 This is a schematic diagram of the signal processing circuit used for gas measurement by GFC method in one embodiment of the present invention.
[0040] Figure 2 This is a circuit diagram of a signal processing circuit for gas measurement using the GFC method in one embodiment of the present invention.
[0041] Figure 3 This is a schematic diagram of the waveforms at each stage of the signal processing circuit in one embodiment of the present invention.
[0042] Figure 4 This is a flowchart of a signal processing method in one embodiment of the present invention.
[0043] Figure 5 This is a schematic diagram of the composition of an electronic device according to an embodiment of the present invention. Detailed Implementation
[0044] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[0045] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.
[0046] The description in this section pertains to only a few typical embodiments, and the present invention is not limited to the scope of the embodiments described. Substitution of identical or similar prior art methods with some technical features in the embodiments is also within the scope of the description and protection of this invention.
[0047] The steps described in the various embodiments in the specification are for illustrative purposes only, and the implementation of this application is not limited by the order of the steps.
[0048] The term "connection" in the specification includes both direct and indirect connections, such as connections made through active devices, passive devices, or electrical conduction media; it may also include connections made by other active or passive devices that are known to those skilled in the art and can achieve the same or similar functional purpose, such as connections made through circuits or components such as switches or follower circuits.
[0049] This invention discloses a signal processing circuit for gas measurement (such as a signal processing circuit for GFC method gas measurement). Figure 1 This is a schematic diagram of the signal processing circuit used for gas measurement using the GFC method in one embodiment of the present invention; please refer to [link / reference]. Figure 1 The signal processing circuit includes: an operational amplifier circuit 1, a sample-and-hold circuit 2, a first differential circuit 3, and a second differential circuit 4.
[0050] The operational amplifier circuit 1 is connected to the sample-and-hold circuit 2, which is connected to the first differential circuit 3 and the second differential circuit 4. The operational amplifier circuit 1 receives the detection signal and amplifies it (e.g., by amplification of 50 times, or other factors). The sample-and-hold circuit 2 separates the reference signal and the measurement signal in the detection signal, and samples and holds the high-level and low-level signals in the reference signal, as well as the high-level and low-level signals in the measurement signal.
[0051] The first differential circuit 3 is used to subtract the high-level signal from the reference signal output by the sample-and-hold circuit 2 from the low-level signal in the reference signal, thereby obtaining the reference signal while removing interference from slowly varying background noise. The second differential circuit 4 is used to subtract the high-level signal from the measurement signal output by the sample-and-hold circuit 2 from the low-level signal in the measurement signal, thereby obtaining the measurement signal while removing interference from slowly varying background noise.
[0052] Figure 2 This is a circuit diagram of a signal processing circuit for gas measurement using the GFC method in one embodiment of the present invention. Figure 3 This is a schematic diagram of the waveforms at each stage of the signal processing circuit in one embodiment of the present invention; please refer to [link / reference]. Figure 2 In one embodiment of the present invention, the sample-and-hold circuit includes a second comparator U2, a second capacitor C2, a fourth capacitor C4, a sixth capacitor C6, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a ninth resistor R9. The second terminal of the second capacitor C2 is connected to the first terminal of the fifth resistor R5. The second terminal of the fifth resistor R5 is connected to the second terminal of the fourth resistor R4 and the non-inverting input terminal of the second comparator U2. The first terminal of the fourth resistor R4 is grounded. The inverting input terminal of the second comparator U2 is connected to the second terminal of the seventh resistor R7, the first terminal of the ninth resistor R9, and the first terminal of the sixth capacitor C6. The first terminal of the seventh resistor R7 is grounded. The output terminal of the second comparator U2 is connected to the second terminal of the ninth resistor R9, the second terminal of the sixth capacitor C6, and the first terminal of the sixth resistor R6. The second terminal of the sixth resistor R6 is connected to the first terminal of the fourth capacitor C4.
[0053] In one embodiment of the present invention, the sample-and-hold circuit includes a first reference signal sample-and-hold circuit, a second reference signal sample-and-hold circuit, a first measurement signal sample-and-hold circuit, and a second measurement signal sample-and-hold circuit. The operational amplifier circuit is respectively connected to the first reference signal sample-and-hold circuit, the second reference signal sample-and-hold circuit, the first measurement signal sample-and-hold circuit, and the second measurement signal sample-and-hold circuit. The first reference signal sample-and-hold circuit and the second reference signal sample-and-hold circuit are connected to a first differential circuit, and the first measurement signal sample-and-hold circuit and the second measurement signal sample-and-hold circuit are respectively connected to a second differential circuit.
[0054] The first reference signal sample-and-hold circuit is used to sample and hold the positive level signal in the reference signal, and the second reference signal sample-and-hold circuit is used to sample and hold the negative level signal in the reference signal. The first measurement signal sample-and-hold circuit is used to sample and hold the positive level signal in the measurement signal, and the second measurement signal sample-and-hold circuit is used to sample and hold the negative level signal in the measurement signal.
[0055] like Figure 2 As shown, in one embodiment of the present invention, the first reference signal sample and hold circuit includes a first switch S1, a first resistor R1, and a first capacitor C1; the first end of the first switch S1 is connected to the operational amplifier circuit, the second end of the first switch S1 is connected to the first end of the first resistor R1, the second end of the first resistor R1 is connected to the second end of the first capacitor C1, and the first end of the first capacitor C1 is grounded.
[0056] The second reference signal sample-and-hold circuit includes a second switch S2, a second resistor R2, and a third capacitor C3; the first end of the second switch S2 is connected to the operational amplifier circuit, the second end of the second switch S2 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the second end of the third capacitor C3, and the first end of the third capacitor C3 is grounded.
[0057] The first measurement signal sampling and holding circuit includes a third switch S3, an eighth resistor R8, and a fifth capacitor C5; the first end of the third switch S3 is connected to the operational amplifier circuit, the second end of the third switch S3 is connected to the first end of the eighth resistor R8, the second end of the eighth resistor R8 is connected to the second end of the fifth capacitor C5, and the first end of the fifth capacitor C5 is grounded.
[0058] The second measurement signal sampling and holding circuit includes a fourth switch S4, a first zero resistor R10, and a seventh capacitor C7; the first end of the fourth switch S4 is connected to the operational amplifier circuit, the second end of the fourth switch S4 is connected to the first end of the first zero resistor R10, the second end of the first zero resistor R10 is connected to the second end of the seventh capacitor C7, and the first end of the seventh capacitor C7 is grounded.
[0059] Please continue reading. Figure 2 In one embodiment of the present invention, the first differential circuit includes a first instrumentation amplifier U1 and a third resistor R3; the non-inverting input terminal of the first instrumentation amplifier U1 is connected to the second terminal of the first resistor R1, and the inverting input terminal of the first instrumentation amplifier U1 is connected to the second terminal of the second resistor R2; the RO port of the first instrumentation amplifier U1 is connected to the first terminal of the third resistor R3, and the RG port of the first instrumentation amplifier U1 is connected to the second terminal of the third resistor R3.
[0060] The second differential circuit includes a third instrumentation amplifier U3 and a first resistor R11; the non-inverting input terminal of the third instrumentation amplifier U3 is connected to the second terminal of the eighth resistor R8, and the inverting input terminal of the third instrumentation amplifier U3 is connected to the second terminal of the first zero resistor R10; the RO port of the third instrumentation amplifier U3 is connected to the first terminal of the first resistor R11, and the RG port of the third instrumentation amplifier U3 is connected to the second terminal of the first resistor R11.
[0061] This invention further discloses a signal processing method for the signal processing circuit used in gas measurement described above. Figure 4 This is a flowchart of a signal processing method according to an embodiment of the present invention; please refer to [link / reference]. Figure 4 The signal processing method includes:
[0062]
Step S1
[0063]
Step S2
[0064]
Step S3
[0065]
Step S4
[0066] This invention also discloses an electronic device, Figure 5 This is a schematic diagram of the composition of an electronic device according to an embodiment of the present invention; please refer to [link / reference]. Figure 5At the hardware level, the electronic device includes a memory, a processor, and at least one communication interface; the processor may be a microprocessor, and the memory may include main memory, such as random access memory (RAM) or non-volatile memory. Of course, the electronic device may also include other hardware as needed.
[0067] The processor, communication interface, and memory can be interconnected via an internal bus. The memory stores programs (including operating system programs and application programs); the programs may include program code, which may include computer operation instructions. The memory may include main memory and non-volatile memory, and provides instructions and data to the processor.
[0068] In one embodiment, the processor can read the corresponding program from non-volatile memory into memory and then run it; the processor can execute the program stored in memory and specifically perform the following operations (e.g. Figure 4 As shown):
[0069]
Step S1
[0070]
Step S2
[0071]
Step S3
[0072]
Step S4
[0073] This invention further discloses a storage medium storing computer program instructions, which, when executed by a processor, implement the following steps of the method of this invention (e.g. Figure 4 As shown):
[0074]
Step S1
[0075]
Step S2
[0076]
Step S3
[0077]
Step S4
[0078] In summary, the signal processing circuit, method, electronic device, and storage medium for gas measurement proposed in this invention can eliminate the influence of slowly varying background noise and extract signals from periodically interleaved reference and measurement signals, which are then divided into two channels for acquisition by the ADC, ensuring accurate and stable measurement.
[0079] It should be noted that this application can be implemented in software and / or a combination of software and hardware; for example, it can be implemented using an application-specific integrated circuit (ASIC), a general-purpose computer, or any other similar hardware device. In some embodiments, the software program of this application can be executed by a processor to implement the steps or functions described above. Similarly, the software program of this application (including related data structures) can be stored in a computer-readable recording medium; for example, RAM memory, magnetic or optical drives, floppy disks, and similar devices. In addition, some steps or functions of this application can be implemented in hardware; for example, as circuitry that cooperates with a processor to perform the various steps or functions.
[0080] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0081] The description and application of the present invention herein are illustrative and not intended to limit the scope of the invention to the embodiments described above. Effects or advantages involved in the embodiments may not be apparent due to various factors, and the description of effects or advantages is not intended to limit the embodiments. Variations and modifications of the embodiments disclosed herein are possible, and various substitutions and equivalents of the components in the embodiments are well known to those skilled in the art. It should be apparent to those skilled in the art that the invention can be implemented in other forms, structures, arrangements, proportions, and with other components, materials, and parts without departing from the spirit or essential characteristics of the invention. Other variations and modifications can be made to the embodiments disclosed herein without departing from the scope and spirit of the invention.
Claims
1. A signal processing circuit for gas measurement, characterized in that, The signal processing circuit includes: an operational amplifier circuit, a sample-and-hold circuit, a first differential circuit, and a second differential circuit; The operational amplifier circuit is connected to the sample-and-hold circuit, and the sample-and-hold circuit is connected to the first differential circuit and the second differential circuit respectively; The operational amplifier circuit is used to receive the detection signal and amplify the detection signal; The sample-and-hold circuit is used to separate the reference signal and the measurement signal in the detection signal, and to sample and hold the high-level signal and the low-level signal in the reference signal, and to sample and hold the high-level signal and the low-level signal in the measurement signal. The first differential circuit is used to subtract the high-level signal in the reference signal output by the sample-and-hold circuit from the low-level signal in the reference signal to obtain the reference signal while removing the interference of background slow-varying noise. The second differential circuit is used to subtract the high-level signal from the measurement signal output by the sample-and-hold circuit from the low-level signal in the measurement signal, thereby obtaining the measurement signal while removing the interference of background slow-varying noise.
2. The signal processing circuit for gas measurement according to claim 1, characterized in that: The sample-and-hold circuit includes a second comparator U2, a second capacitor C2, a fourth capacitor C4, a sixth capacitor C6, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a ninth resistor R9. The second terminal of the second capacitor C2 is connected to the first terminal of the fifth resistor R5. The second terminal of the fifth resistor R5 is connected to the second terminal of the fourth resistor R4 and the non-inverting input terminal of the second comparator U2. The first terminal of the fourth resistor R4 is grounded. The inverting input of the second comparator U2 is connected to the second terminal of the seventh resistor R7, the first terminal of the ninth resistor R9, and the first terminal of the sixth capacitor C6, respectively. The first terminal of the seventh resistor R7 is grounded. The output of the second comparator U2 is connected to the second terminal of the ninth resistor R9, the second terminal of the sixth capacitor C6, and the first terminal of the sixth resistor R6, respectively; the second terminal of the sixth resistor R6 is connected to the first terminal of the fourth capacitor C4.
3. The signal processing circuit for gas measurement according to claim 1, characterized in that: The sample-and-hold circuit includes a first reference signal sample-and-hold circuit, a second reference signal sample-and-hold circuit, a first measurement signal sample-and-hold circuit, and a second measurement signal sample-and-hold circuit. The operational amplifier circuit is connected to the first reference signal sample and hold circuit, the second reference signal sample and hold circuit, the first measurement signal sample and hold circuit, and the second measurement signal sample and hold circuit, respectively. The first reference signal sample-and-hold circuit and the second reference signal sample-and-hold circuit are connected to the first differential circuit, and the first measurement signal sample-and-hold circuit and the second measurement signal sample-and-hold circuit are respectively connected to the second differential circuit; The first reference signal sample and hold circuit is used to sample and hold the positive level signal in the reference signal, and the second reference signal sample and hold circuit is used to sample and hold the negative level signal in the reference signal; The first measurement signal sample-and-hold circuit is used to sample and hold the positive level signal in the measurement signal, and the second measurement signal sample-and-hold circuit is used to sample and hold the negative level signal in the measurement signal.
4. The signal processing circuit for gas measurement according to claim 3, characterized in that: The first reference signal sample and hold circuit includes a first switch S1, a first resistor R1, and a first capacitor C1; the first end of the first switch S1 is connected to the operational amplifier circuit, the second end of the first switch S1 is connected to the first end of the first resistor R1, the second end of the first resistor R1 is connected to the second end of the first capacitor C1, and the first end of the first capacitor C1 is grounded. The second reference signal sample-and-hold circuit includes a second switch S2, a second resistor R2, and a third capacitor C3; the first end of the second switch S2 is connected to the operational amplifier circuit, the second end of the second switch S2 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the second end of the third capacitor C3, and the first end of the third capacitor C3 is grounded.
5. The signal processing circuit for gas measurement according to claim 3, characterized in that: The first measurement signal sampling and holding circuit includes a third switch S3, an eighth resistor R8, and a fifth capacitor C5; the first end of the third switch S3 is connected to the operational amplifier circuit, the second end of the third switch S3 is connected to the first end of the eighth resistor R8, the second end of the eighth resistor R8 is connected to the second end of the fifth capacitor C5, and the first end of the fifth capacitor C5 is grounded. The second measurement signal sampling and holding circuit includes a fourth switch S4, a first zero resistor R10, and a seventh capacitor C7; the first end of the fourth switch S4 is connected to the operational amplifier circuit, the second end of the fourth switch S4 is connected to the first end of the first zero resistor R10, the second end of the first zero resistor R10 is connected to the second end of the seventh capacitor C7, and the first end of the seventh capacitor C7 is grounded.
6. The signal processing circuit for gas measurement according to claim 5, characterized in that: The first differential circuit includes a first instrumentation amplifier U1 and a third resistor R3; the non-inverting input terminal of the first instrumentation amplifier U1 is connected to the second terminal of the first resistor R1, and the inverting input terminal of the first instrumentation amplifier U1 is connected to the second terminal of the second resistor R2; the RO port of the first instrumentation amplifier U1 is connected to the first terminal of the third resistor R3, and the RG port of the first instrumentation amplifier U1 is connected to the second terminal of the third resistor R3.
7. The signal processing circuit for gas measurement according to claim 5, characterized in that: The second differential circuit includes a third instrumentation amplifier U3 and a first resistor R11; the non-inverting input terminal of the third instrumentation amplifier U3 is connected to the second terminal of the eighth resistor R8, and the inverting input terminal of the third instrumentation amplifier U3 is connected to the second terminal of the first zero resistor R10; the RO port of the third instrumentation amplifier U3 is connected to the first terminal of the first resistor R11, and the RG port of the third instrumentation amplifier U3 is connected to the second terminal of the first resistor R11.
8. A signal processing method for a signal processing circuit for gas measurement according to any one of claims 1 to 7, characterized in that, The signal processing method includes: The operational amplifier circuit receives the detection signal and amplifies it; The sample-and-hold circuit separates the reference signal and the measurement signal in the detection signal, and samples and holds the high-level signal and the low-level signal in the reference signal, and samples and holds the high-level signal and the low-level signal in the measurement signal. The first differential circuit subtracts the high-level signal from the reference signal output by the sample-and-hold circuit from the low-level signal in the reference signal to obtain the reference signal while removing the interference of slowly varying background noise. The second differential circuit subtracts the high-level signal from the sample-and-hold circuit's output measurement signal from the low-level signal in the measurement signal, obtaining the measurement signal while removing background slow-varying noise interference.
9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method of claim 8.
10. A storage medium storing computer program instructions thereon, characterized in that, When the computer program instructions are executed by the processor, they implement the steps of the method of claim 8.