A circuit processing subsystem of a particle monitoring device

Abstract

The present invention provides a circuit processing subsystem of a particle monitoring device, which includes: a photoelectric detection unit, which is used to convert the optical signal collected from its detection area into an electrical signal; a high impedance transconductance amplification unit, which is used to amplify the electrical signal; an AC coupling unit, which is used to suppress the background light interference of the amplified electrical signal and perform noise reduction on the sensor signal; a phase-locked amplification unit, which is used to further perform noise reduction on the electrical signal after the background light interference is suppressed; a differential amplification unit, which is used to further amplify and reduce the noise of the signal; an analog-to-digital conversion unit, which is used to perform analog-to-digital conversion on the signal; and a control unit, which is used to control the laser modulation signal and perform corresponding particle monitoring according to the received digital signal. The technical solution of the present invention can effectively solve the problems that the existing dust sensor is seriously interfered by the background light and has serious noise, so as to achieve more accurate and efficient particle monitoring.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a circuit processing subsystem of a particle monitoring device. Background Art

[0002] As people's living standards improve, their requirements for health and safety are also gradually increasing. How to effectively monitor and warn of dust pollution in the environment, such as smoke, haze, mist, fine dust or smog, has become an extremely serious problem at present. Therefore, laser dust sensors have become an indispensable type of equipment in people's lives, among which ultra-low emission laser scattering dust sensors are typical.

[0003] However, the existing ultra-low emission laser scattering dust sensors have many shortcomings, such as: serious interference from background light, laboratory environment, dark environment in chimney, or sunlight environment, etc. have a great impact on the measurement data; serious noise affects the surrounding environment; often achieve high signal-to-noise ratio through multi-range switching, but this operation method is easy to cause loopholes for falsification of environmental protection data, etc. The above problems are technical problems that need to be solved urgently in this field. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the present invention provides a circuit processing subsystem of a particulate matter monitoring device, which is used to solve the problems in the prior art.

[0005] To achieve the above-mentioned purpose, the present invention provides a circuit processing subsystem of a particulate matter monitoring device, which includes: a signal generator for emitting a signal of a preset frequency, waveform, and output level; a laser driver for receiving the signal generated by the signal generator and emitting a corresponding laser drive signal; a laser for receiving the laser drive signal emitted by the laser driver and emitting a corresponding laser signal; a photoelectric detection unit for converting an optical signal collected from its detection area into an electrical signal; a high-impedance transconductance amplification unit, whose input end is coupled to the output end of the photoelectric detection unit, for amplifying the electrical signal; and an AC coupling unit, whose input end is coupled to the output end of the high-impedance transconductance amplification unit. The output end is used to suppress the background light interference of the amplified electrical signal and perform noise reduction processing on the sensor signal; the phase-locked amplifier unit, whose input end is coupled to the output end of the AC coupling unit, is used to further perform noise reduction processing on the electrical signal after the background light interference is suppressed; the differential amplifier unit, whose input end is coupled to the output end of the phase-locked amplifier unit, is used to further amplify and reduce the noise of the electrical signal; the analog-to-digital conversion unit, whose input end is coupled to the output end of the differential amplifier unit, is used to perform analog-to-digital conversion on the signal; the control unit, whose input end is coupled to the output end of the analog-to-digital conversion unit, is used to control the laser modulation signal and perform corresponding particle monitoring according to the received digital signal.

[0006] In some embodiments of the present invention, the high impedance transconductance amplification unit includes: a first signal amplifier, whose first input pin is connected to the input signal of the photodetection unit, the second input pin is grounded, and the input signal is amplified and output through the output pin.

[0007] In some embodiments of the present invention, the AC coupling unit includes: a multi-stage amplification unit; a first filter capacitor; and a second filter capacitor; wherein the output signal of the high-impedance transconductance amplification unit is filtered by the first filter capacitor and then input into the multi-stage amplification unit, output to the second filter capacitor after multi-stage amplification processing, and output after filtering by the second filter capacitor.

[0008] In some embodiments of the present invention, the multi-stage amplification unit includes: a first-stage amplification unit, which includes a second signal amplifier; a second-stage amplification unit, which includes a third signal amplifier; a third-stage amplification unit, which includes a fourth signal amplifier; wherein the first filter capacitor filters the signal and inputs it into the second signal amplifier; the second signal amplifier amplifies the signal and outputs it to the input end of the third signal amplifier; the third signal amplifier amplifies the signal and outputs it to the input end of the fourth signal amplifier; the fourth signal amplifier amplifies the signal and outputs it after filtering it through the second filter capacitor.

[0009] In some embodiments of the present invention, the differential amplification unit includes a high-precision differential amplifier.

[0010] In some embodiments of the present invention, the lock-in amplification unit comprises a lock-in amplifier.

[0011] In some embodiments of the present invention, the analog-to-digital conversion unit is an analog-to-digital converter.

[0012] In some embodiments of the present invention, the control unit includes: any one or more combinations of an ARM controller, an FPGA controller, a SoC controller, a DSP controller, and an MCU controller.

[0013] In some embodiments of the present invention, the type of particulate matter monitoring device includes an ultra-low emission laser scattering dust sensor.

[0014] As described above, the circuit processing subsystem of a particle monitoring device involved in the present invention has the following beneficial effects: the technical solution of the present invention can effectively solve the problems of existing dust sensors being severely interfered by background light and having severe noise, thereby achieving more accurate and efficient particle monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1Shown is a partial structural schematic diagram of a circuit processing subsystem of a particulate matter monitoring device in one embodiment of the present invention.

[0016] Figure 2 Shown is a structural schematic diagram of a circuit processing subsystem of a particulate matter monitoring device in one embodiment of the present invention.

[0017] Figure 3 Shown is a structural schematic diagram of a high impedance transconductance amplifier in one embodiment of the present invention.

[0018] Figure 4 FIG. 4 is a schematic structural diagram of an AC coupler in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0020] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification, so that people familiar with this technology can understand and read them, and are not used to limit the limiting conditions that the present invention can implement, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope of the technical content disclosed by the present invention. The following detailed description should not be considered restrictive, and the scope of the embodiments of the present application is limited only by the claims of the published patents. The terms used here are only for describing specific embodiments and are not intended to limit the present application. Spatially related terms, such as "upper", "lower", "left", "right", "below", "below", "lower", "above", "upper", etc., can be used in the text to facilitate the description of the relationship between an element or feature shown in the figure and another element or feature.

[0021] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix", "hold" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] Furthermore, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless there is an indication to the contrary in the context. It should be further understood that the terms "comprise", "include" indicate the presence of the described features, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence or addition of one or more other features, operations, elements, components, items, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Therefore, "A, B or C" or "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". Exceptions to this definition will only occur when the combination of elements, functions or operations is inherently mutually exclusive in some way.

[0023] The laser scattering dust sensor is a device used to monitor particulate matter. It mainly uses the laser scattering principle, that is, when the laser shines on the particles passing through the detection position, it will produce weak light scattering. The light scattering waveform in a specific direction is related to the particle diameter. The real-time number concentration of particles of different particle sizes is obtained through waveform classification statistics and conversion formulas of different particle sizes, and the mass concentration consistent with the official unit is obtained according to the calibration method.

[0024] However, existing ultra-low emission laser scattering dust sensors have many shortcomings. For example, they are severely affected by background light interference. The laboratory environment, the dark environment in the chimney, or the sunlight environment have a great impact on the measurement data; the noise is serious and affects the surrounding environment; high signal-to-noise ratio is often achieved through multi-range switching, but this operation method is prone to loopholes in the falsification of environmental data, etc.

[0025] In view of this, the present application provides a dust sensor, which aims to solve the problems in the prior art by adding a circuit module for reducing noise and suppressing background light interference, so as to make the dust monitoring of the dust sensor more accurate and efficient.

[0026] In order to make the purpose, technical solution and advantages of this application more clear, the technical solution in the embodiment of the present invention is further described in detail through the following embodiments and in combination with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the present invention and are not used to limit the invention.

[0027] Embodiment 1

[0028] like Figure 1, a partial structural diagram of a circuit processing subsystem of a particle monitoring device in an embodiment of the present application is shown. The circuit processing subsystem of the particle monitoring device in this embodiment includes a photoelectric detection unit 11, a high impedance transconductance amplifier unit 12, an AC coupling unit 13, a phase-locked amplifier unit 14, a differential amplifier unit 15, an analog-to-digital conversion unit 16, and a control unit 17.

[0029] It should be noted that the particulate matter referred to in this embodiment mainly refers to solid particles suspended in the air, including but not limited to: dust, smoke, haze, mist, fine dust or smoke, etc.

[0030] Among them, the photoelectric detection unit 11 can be, for example, a photoelectric detector, which is used to convert the light signal collected from its detection area into an electrical signal; the high-impedance transconductance amplifier unit 12 can be, for example, a high-impedance transconductance amplifier, whose input end is coupled to the output end of the photoelectric detection unit 11, for amplifying the electrical signal; the AC coupling unit 13 can be, for example, a capacitor AC coupling circuit, whose input end is coupled to the output end of the high-impedance transconductance amplifier unit 12, for suppressing the background light interference of the amplified electrical signal and performing noise reduction processing on the sensor signal; the phase-locked amplifier unit 14 can be, for example, a phase-locked amplifier, whose input end is coupled to the output end of the AC coupling unit 13, for further performing noise reduction processing on the electrical signal after the background light interference is suppressed; the differential amplifier unit 15 can be, for example, a differential amplifier, whose input end is coupled to the output end of the phase-locked amplifier unit 14, for further amplifying and noise reduction processing on the electrical signal; the analog-to-digital conversion unit 16 can be, for example, an analog-to-digital conversion circuit, whose input end is coupled to the output end of the differential amplifier unit 15, for performing analog-to-digital conversion on the signal; the control unit 17 can be, for example, an ARM (Advanced A device such as a RISC Machines) controller, a FPGA (Field Programmable Gate Array) controller, a SoC (System on Chip) controller, a DSP (Digital Signal Processing) controller, or an MCU (Microcontroller Unit) controller, whose input end is coupled to the output end of the analog-to-digital conversion unit 16, is used to control the laser modulation signal and perform corresponding particle monitoring according to the received digital signal.

[0031] It should be noted that the "coupling" mentioned in this embodiment refers to a coupling connection, which includes but is not limited to a direct or indirect signal transmission relationship between communication devices of one or more of electrical, optical, magnetic and acoustic signals. It should also be understood that the above examples are provided for illustrative purposes and should not be construed as limiting.

[0032] Embodiment 2

[0033] like Figure 2 , which shows a schematic diagram of the structure of the circuit processing subsystem of the particle monitoring device of the present application. In this embodiment, the circuit processing subsystem of the particle monitoring device includes: a signal generator 201, a laser driving circuit 202, a laser 203, a photodetector 205, a high impedance transconductance amplifier 206, an AC coupler 207, a lock-in amplifier 208, a differential amplifier 209, an analog-to-digital converter 210, and a controller 211.

[0034] The signal generator 201 generates a signal and sends it to the laser driving circuit 202 . The laser driving circuit 202 sends a driving signal to the laser 203 . The laser 203 then emits a laser signal to the object under test 204 .

[0035] The photodetector 205 is used to convert the light signal collected from its detection area into an electrical signal; the input end of the high impedance transconductance amplifier 206 is coupled to the output end of the photodetector 205 for amplifying the electrical signal; the input end of the AC coupler 207 is coupled to the output end of the high impedance transconductance amplifier 206 for suppressing background light interference on the amplified electrical signal and performing noise reduction on the sensing signal; the input end of the phase-locked amplifier 254 is coupled to the output end of the AC coupler 207 for further performing noise reduction on the electrical signal after the background light interference is suppressed; the input end of the differential amplifier 208 is coupled to the output end of the phase-locked amplifier 254 for further amplifying and reducing the noise of the electrical signal; the input end of the analog-to-digital converter 209 is coupled to the output end of the differential amplifier 208 for performing analog-to-digital conversion on the signal; the input end of the controller 211 is coupled to the output end of the analog-to-digital converter 209 for controlling the laser modulation signal and performing corresponding particle monitoring according to the received digital signal.

[0036] In some optional implementations, the circuit structure of the high impedance transconductance amplifier 206 is as follows: Figure 3 As shown: the high impedance transconductance amplifier includes a first signal amplifier, which is represented by an operational amplifier U1 in this embodiment. Pin 2 of the operational amplifier U1 is connected to the photodetector, pin 3 is grounded, pin 6 is an output pin, and a feedback resistor R1 is connected between pins 2 and 6, so the operational amplifier U1 amplifies the output signal of the photodetector and outputs it.

[0037] In some optional implementations, the circuit structure of the AC coupler 207 is as follows: Figure 4As shown: the AC coupler includes a multi-stage amplification unit, a first filter capacitor C2 and a second filter capacitor C3. In this embodiment, the multi-stage amplification unit specifically includes: a first-stage amplification unit 41, a second-stage amplification unit 42, and a third-stage amplification unit; wherein the first-stage amplification unit 41 includes a second signal amplifier and its auxiliary circuit, a third signal amplifier and its auxiliary circuit, and a fourth signal amplifier and its auxiliary circuit; and an amplifier U3A is used to represent the second signal amplifier, an amplifier U2 is used to represent the third signal amplifier, and an amplifier U4A is used to represent the fourth signal amplifier.

[0038] It should be understood that the above embodiments are only examples and are not a limitation of the present application. That is, the number of amplification units included in the multi-stage amplification unit is not limited by the above embodiments, and the number of amplification units included can be less than three or more than three, which is not limited in the present embodiment.

[0039] Specifically, the input end of the AC coupler is connected to the output end of the previous stage circuit, that is, connected to the output end of the high impedance transconductance amplifier in this embodiment, and is filtered by the first filter capacitor C2 and then amplified by the amplifier U3A, and output from the pin 1 of the operational amplifier U3A. The output signal of the amplifier U3A is used as the input signal of the amplifier U2, and the signal is introduced from the pin 4 of the amplifier U2, and is amplified by the amplifier U2 and output from the pin 7. The output signal of the second stage signal amplifier U2 is used as the input signal of the amplifier U4A, and the signal is introduced from the pin 2 of the amplifier U4A, and is amplified by the amplifier U4A and filtered by the second filter capacitor C3 before being output.

[0040] It should be noted that the AC coupler in this embodiment is completely different from the traditional filtering method using a single capacitor. The technical solution of this embodiment not only uses a filter capacitor to perform DC isolation and AC filtering, but also dynamically adjusts the signal through a multi-stage amplifier, thereby achieving a filtering effect and more effectively suppressing the interference of background light in environments such as laboratories, darkness, or illumination.

[0041] In some optional implementations, the phase-sensitive detector is used to detect the signal of the specified frequency and phase by the phase-locked amplifier 254. In this embodiment, the phase-locked amplifier 254 receives the output signal of the AC coupler 207 as the measured signal, and receives the output signal of the signal generator 201 as the reference signal to perform signal detection, thereby further achieving noise reduction and suppression of background light interference.

[0042] In some optional implementations, the differential amplifier 208 preferably uses an ultra-high precision differential amplifier circuit, for example, a high-precision differential amplifier with a KCMR of 140dB and ric ≥ 100MΩ is selected, which has significantly higher precision than a general-purpose operational amplifier with a KCMR of (80-120)dB. Therefore, the high-precision differential amplifier used in this embodiment achieves high precision while also obtaining an ultra-large measurement range, so there is no need to achieve a high signal-to-noise ratio through multi-range switching, thereby eliminating the phenomenon of falsification of environmental protection data. However, it should be understood that the parameters listed in the above examples are only for reference and should not be understood as restrictive.

[0043] In summary, the present invention provides a circuit processing subsystem of a particle monitoring device, which can effectively solve the problems of existing dust sensors being seriously interfered by background light and having serious noise, thereby achieving more accurate and efficient particle monitoring. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0044] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A circuit processing subsystem of a particle monitoring device, characterized in that: include: A signal generator for transmitting a signal of a preset frequency, waveform, and output level; A laser driver, which receives the signal generated by the signal generator and emits a corresponding laser driving signal; A laser device, which receives a laser driving signal emitted by the laser driver and emits a corresponding laser signal; A photoelectric detection unit, used to convert the optical signal collected from its detection area into an electrical signal; A high impedance transconductance amplifying unit, whose input end is coupled to the output end of the photoelectric detection unit, and is used to amplify the electrical signal; An AC coupling unit, whose input end is coupled to the output end of the high impedance transconductance amplification unit, and is used to suppress background light interference on the amplified electrical signal and perform noise reduction processing on the sensor signal; A phase-locked amplifier unit, whose input end is coupled to the output end of the AC coupling unit, for further performing noise reduction processing on the electrical signal after background light interference is suppressed; A differential amplifier unit, whose input end is coupled to the output end of the phase-locked amplifier unit, for further amplifying and noise reduction processing the electrical signal; an analog-to-digital conversion unit, whose input end is coupled to the output end of the differential amplification unit, and is used to perform analog-to-digital conversion on the signal; A control unit, whose input end is coupled to the output end of the analog-to-digital conversion unit, for controlling the laser modulation signal and performing corresponding particulate matter monitoring according to the received digital signal; The high impedance transconductance amplification unit comprises: a first signal amplifier, a first input pin of which is connected to the input signal of the photoelectric detection unit, a second input pin is grounded, and the input signal is amplified and outputted through an output pin; The AC coupling unit comprises: a multi-stage amplification unit; a first filter capacitor; and a second filter capacitor; wherein the output signal of the high impedance transconductance amplification unit is filtered by the first filter capacitor and then input into the multi-stage amplification unit, and then output to the second filter capacitor after multi-stage amplification processing, and then output after filtering by the second filter capacitor; The multi-stage amplification unit includes: a first-stage amplification unit, which includes a second signal amplifier; a second-stage amplification unit, which includes a third signal amplifier; a third-stage amplification unit, which includes a fourth signal amplifier; wherein the first filter capacitor filters the signal and inputs it into the second signal amplifier; the second signal amplifier amplifies the signal and outputs it to the input end of the third signal amplifier; the third signal amplifier amplifies the signal and outputs it to the input end of the fourth signal amplifier; the fourth signal amplifier amplifies the signal and outputs it after filtering it through the second filter capacitor.

2. The circuit processing subsystem of the particle monitoring device according to claim 1, characterized in that: The differential amplification unit includes a high-precision differential amplifier.

3. The circuit processing subsystem of the particle monitoring device according to claim 1, characterized in that: The lock-in amplification unit includes a lock-in amplifier.

4. The circuit processing subsystem of the particle monitoring device according to claim 1, characterized in that: The analog-to-digital conversion unit is an analog-to-digital converter.

5. The circuit processing subsystem of the particle monitoring device according to claim 1, characterized in that: The control unit includes: any one or more combinations of an ARM controller, an FPGA controller, a SoC controller, a DSP controller, and an MCU controller.

6. The circuit processing subsystem of the particle monitoring device according to claim 1, characterized in that: The types of particulate matter monitoring devices include ultra-low emission laser scattering dust sensors for dust monitoring.

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