Receiving and amplifying module and receiving and transmitting device based on gas detection instrument

Abstract

The utility model provides a receiving and amplifying module based on a gas detection instrument and a receiving and transmitting device, and the receiving and amplifying module based on the gas detection instrument comprises a transimpedance amplifying unit, a gain control unit, a post-stage amplifying unit and an amplitude detection unit, a feedback part of the transimpedance amplification unit is connected with the output of the gain control unit, the output of the transimpedance amplification unit is connected with the input of the post-stage amplification unit, the output of the post-stage amplification unit is connected with the input of the amplitude detection unit, and the output of the amplitude detection unit is connected with the input of the gain control unit; the transmitting and receiving device based on the gas detection instrument comprises a laser transmitting module, a detector and a receiving and amplifying module. According to the utility model, the amplitude is obtained through the amplitude detection unit, the gain control unit automatically controls the switching of N-gear gains, and when the on-site gas concentration changes or the light path changes, the light path adjustment of the gas detection instrument can be automatically realized.

Description

Technical Field

[0001] The utility model relates to the field of gas detection, and particularly to a receiving and amplifying module and a transceiver device based on a gas detection instrument. Background Art

[0002] Tunable diode laser absorption spectroscopy (TDLAS) uses narrow-band laser to scan the absorption lines of gas molecules, and the concentration of the gas to be measured is obtained by analyzing the laser intensity absorbed by the gas analysis.

[0003] In a gas detection instrument based on the TDLAS principle, the core transceiver device includes a tunable laser, a detector, and a receiving and amplifying module. In addition, there are other devices including optical devices such as absorption cells (Herriott gas cells, White cells, etc.) and mirrors. Due to the different emission optical paths of the laser and the different gas concentrations at the measurement site, the intensities of the received echo signals are different. Most of the receiving and amplifying circuits on the market are as follows: (1) An amplifying circuit with a fixed gain, and the dynamic range is relatively narrow; (2) An amplifying circuit with manual gain control, and the gain of the amplifying circuit is adjusted according to the actual situation on site. When the gas concentration at the site changes or the light intensity changes due to other factors, the gain of the amplifying circuit cannot be adjusted in real time. Summary of the Utility Model

[0004] To solve the above problems, the utility model provides a receiving and amplifying module and a transceiver device based on a gas detection instrument. The tunable laser emits laser, the detector receives the echo beam and generates an electrical signal, and then the electrical signal is amplified by the receiving and amplifying unit. The amplitude is obtained by the amplitude detection unit, and according to the magnitude of the amplitude, the gain control unit automatically switches between N gears of gain. When the gas concentration at the site changes or the optical path changes, the optical path of the gas detection instrument can be automatically adjusted.

[0005] An object of the utility model is to provide a receiving and amplifying module based on a gas detection instrument.

[0006] The above object is achieved by the following technical solutions:

[0007] A receiving and amplifying module based on a gas detection instrument includes:

[0008] 1 transimpedance amplifying unit, which consists of 1 transimpedance amplifying circuit;

[0009] 1 gain control unit, which includes 1 gain control circuit and N gain circuits, N≥2;

[0010] 1 post-stage amplifying unit, which consists of 1 operational amplifier circuit;

[0011] One amplitude detection unit;

[0012] The output of the feedback connection gain control unit of the transimpedance amplification unit is connected to the input of the subsequent stage amplification unit. The output of the transimpedance amplification unit is connected to the input of the subsequent stage amplification unit, the output of the subsequent stage amplification unit is connected to the input of the amplitude detection unit, and the output of the amplitude detection unit is connected to the input of the gain control unit;

[0013] Preferably, the N gain circuits include at least N - 2 T-type resistor network circuits.

[0014] Furthermore, the one gain control circuit includes one multiplex decoder.

[0015] Preferably, the one gain control circuit further includes N switch circuits.

[0016] Furthermore, the amplitude detection unit includes, but is not limited to, an analog-to-digital circuit and a comparator detection circuit.

[0017] Preferably, N ≤ 16.

[0018] Another object of the present invention is to provide a transceiver device based on a gas detection instrument.

[0019] The above object is achieved by the following technical solutions:

[0020] A transceiver device based on a gas detection instrument includes: a laser emission module, a detector, and the above-mentioned receiving and amplifying module;

[0021] The laser emission module includes one laser driver and one laser, and is used to drive the laser to generate an outgoing light beam;

[0022] The detector is used to receive the echo light beam of the laser and generate an echo electrical signal;

[0023] The receiving and amplifying module is used to amplify the echo electrical signal and control the switching of the N gain circuits by the gain control circuit according to the amplitude detected by the above-mentioned amplitude detection unit.

[0024] Preferably, the laser is a tunable laser.

[0025] Furthermore, the detector includes, but is not limited to, PD, APD, SiPM, SPAD.

[0026] Preferably, it further includes a gas absorption cell. Description of the Drawings

[0027] Figure 1 It is a block diagram of the receiving and amplifying module of the gas detection instrument according to an embodiment of the present invention.

[0028] Figure 2 It is a schematic diagram of a gain control unit according to an embodiment of the present utility model.

[0029] Figure 3 It is a block diagram of a transceiver device of a gas detection instrument according to an embodiment of the present utility model. Detailed implementation manners

[0030] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are only a part rather than all of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the scope of protection of the present utility model.

[0031] In the following description, specific details such as specific system architectures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, those skilled in the art should understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0032] As used in the description of the specification and claims of the present application, the term "if" can be interpreted as "when", "once", "in response to determining" or "in response to detecting" according to the context. Similarly, the phrase "if determined" or "if [the described condition or event] is detected" can be interpreted as meaning "once determined", "in response to determining", "once [the described condition or event] is detected" or "in response to detecting [the described condition or event]" according to the context.

[0033] In the description of the specification and claims of the present application, the terms "first", "second", "third", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0034] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that specific features, structures, or characteristics described in connection with that embodiment are included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0035] Figure 1 The block diagram of the receiving and amplifying module 100 of a gas detection instrument according to an embodiment of the present utility model is shown. Figure 2 The schematic diagram of the gain control unit 102 according to an embodiment of the present utility model is shown. In this embodiment, N = 8, as Figure 1 shown, the receiving and amplifying module 100 of this embodiment includes:

[0036] 1 transimpedance amplifying unit 101, which consists of 1 transimpedance amplifying circuit;

[0037] 1 gain control unit 102, which includes 1 gain control circuit 201 and 8 gain circuits;

[0038] 1 post-stage amplifying unit 103, which consists of 1 operational amplifier circuit;

[0039] 1 amplitude detection unit 104;

[0040] The feedback of the transimpedance amplifying unit 101 is connected to the output of the gain control unit 102, the output of the transimpedance amplifying unit 101 is connected to the input of the post-stage amplifying unit 103, the output of the post-stage amplifying unit 103 is connected to the input of the amplitude detection unit 104, and the output of the amplitude detection unit 104 is connected to the input of the gain control unit 102.

[0041] Preferably, the amplitude detection unit 104 can be an analog-to-digital circuit or a comparator detection circuit.

[0042] In practical applications, the gain control unit 102 defaults to the gain of the middle gear. After the transimpedance amplification unit 101 and the post-stage amplification unit 103 amplify the echo signal, the amplitude detection unit 104 obtains the amplitude of the currently amplified signal. The system determines whether to increase or decrease the amplification factor based on the detected amplitude, and then the gain control unit 102 controls the adjustment of the gain. It should be noted that the system's judgment of the amplitude can be implemented by devices such as MCU, FPGA, CPLD, DSP, etc., or can also be implemented by other circuits, which is a well-known technology in the industry and not the protected content of this patent. This is explained here to avoid unnecessary misunderstandings.

[0043] As Figure 2 shown, the gain control unit 102 of this embodiment includes: 1 gain control circuit and N gain circuits. Preferably, the 1 gain control circuit includes 1 multi-channel decoder 201 and N switch circuits. The multi-channel decoder 201 controls the output of a total of 8 channels Y0 - Y7 by controlling the levels of three pins A0, A1, and A2. The truth function table of the output is shown in Table 1 below:

[0044] Table 1 Truth table of decoder 201

[0045]

[0046] In this embodiment, N = 8, and the N switch circuits are composed of 8 N-channel MOS transistors Q1, Q2... Q8. When the corresponding channel Yx (x = 1... 8) is at a high level, the gate (G) of the corresponding channel MOS transistor Qx (x = 1... 8) is at a high level, and the drain (D terminal) and source (S) of the MOS transistor are conducting.

[0047] It should be noted that there are various forms of switch circuits, and it can also be other forms such as digital switch chips. This is only an example here and does not limit the scope of the present invention.

[0048] In this embodiment, the N gain circuits include 2 ordinary resistor network circuits and N - 2 T-shaped resistor network circuits, which are composed of Figure 2 resistors R1, R2, and Ry (y = 3... 8). As the feedback resistor of the transimpedance amplification unit 101, it determines the amplification factor of the transimpedance amplification unit 101. The amplification factor A is:

[0049] A = -i(R1 + R2 + R1 * R2 / Ry), R 总 = R1 + R2 + R1 * R2 / Ry. By changing the value of R 总 the gain of the transimpedance amplification circuit can be changed. Next, the gain of the corresponding amplification circuit will be illustrated with actual values.

[0050] For example: R1 = 1K, R2 = 2.16k

[0051] (1) First - stage gain. At this time, A2 - A1 - A0 is 000, the Y0 channel outputs a high level, Q1 conducts, then R2 is short - circuited. Therefore, the feedback resistor R 总 = R1 = 1K, with the current gain as the reference 0db;

[0052] (2) Second - stage gain. At this time, A2 - A1 - A0 is 001, the Y1 channel outputs a high level, Q2 conducts, but Q2 is not connected to any loop. Therefore, the feedback resistor R 总 = R1 + R2 = 3.16K, and the corresponding gain is: 20 * log(3.16K / 1K)=20 * 0.499db = 9.99db≈10db;

[0053] (3) Third - stage gain. At this time, A2 - A1 - A0 is 010, the Y2 channel outputs a high level, Q3 conducts, the drain (D - terminal) of Q3 is grounded. Assuming Ry = R3 = 315Ω, then the feedback resistor R 总 = R1 + R2+R1 * R2 / R3=(1K + 2.16K)+1K * 2.16K / 315 = 10017, and the corresponding gain is: 20 * log(10.017K / 1K)≈20db;

[0054] (4) Fourth - stage gain. At this time, A2 - A1 - A0 is 011, the Y3 channel outputs a high level, Q4 conducts, the drain (D - terminal) of Q4 is grounded. Assuming Ry = R4 = 76Ω, then the feedback resistor R 总 = R1 + R2+R1 * R2 / R4=(1K + 2.16K)+1K * 2.16K / 76 = 31581, and the corresponding gain is: 20 * log(31.581K / 1K)=29.98db≈30db;

[0055] (5) Fifth - stage gain. At this time, A2 - A1 - A0 is 100, the Y4 channel outputs a high level, Q5 conducts, the drain (D - terminal) of Q5 is grounded. Assuming Ry = R5 = 22.3Ω, then the feedback resistor R 总 = R1 + R2+R1 * R2 / R5=(1K + 2.16K)+1K * 2.16K / 22.3 = 100020, and the corresponding gain is: 20 * log(100.02K / 1K)≈40db;

[0056] (6) Sixth - stage gain. At this time, A2 - A1 - A0 is 101, the Y5 channel outputs a high level, Q6 conducts, the drain (D - terminal) of Q3 is grounded. Assuming Ry = R6 = 6.9Ω, then the feedback resistor R 总= R1 + R2 + R1 * R2 / R6 = (1K + 2.16K) + 1K * 2.16K / 6.9 = 316203, and the corresponding gain is: 20 * log(316.203K / 1K) ≈ 50db;

[0057] (7) The seventh gain level, at this time A2 - A1 - A0 is 110, the Y6 channel outputs a high level, Q7 is turned on, the drain (D terminal) of Q3 is grounded. Assuming Ry = R7 = 2.16Ω, then the feedback resistor R 总 = R1 + R2 + R1 * R2 / R7 = (1K + 2.16K) + 1K * 2.16K / 2.16 = 1003160, and the corresponding gain is: 20 * log(1003.16K / 1K) ≈ 60db;

[0058] (8) The eighth gain level, at this time A2 - A1 - A0 is 111, the Y7 channel outputs a high level, Q8 is turned on, the drain (D terminal) of Q3 is grounded. Assuming Ry = R3 = 0.68Ω, then the feedback resistor R 总 = R1 + R2 + R1 * R2 / R8 = (1K + 2.16K) + 1K * 2.16K / 0.68 = 3179630, and the corresponding gain is: 20 * log(3179.63K / 1K) ≈ 70db;

[0059] In summary, the multiples achieved by the 8 - gain levels are 1K, 3.16K, 10K, 31.6K, 100K, 316K, 1003K, 3179.6K respectively, and the corresponding dbs are 0db, 10db, 20db, 30db, 40db, 50db, 60db, 70db respectively.

[0060] It should be noted that the data listed above are only examples and do not limit the present utility model; in this embodiment, only 8 - gain levels are taken as examples, which do not limit the present utility model. In practice, it can be applied in any number of gain levels such as 2 - gain levels, 3 - gain levels... 16 - gain levels.

[0061] It should also be noted that the present utility model includes at least N - 2 T - type resistor network circuits. The N - 1 or N gain circuits can all be T - type resistor networks. For example, when there are only 2 - gain levels, the 2 - gain levels can be achieved by a decoder and other forms of gain circuits, or by 1 ordinary resistor network + 1 T - type resistor network, or both can be achieved by T - type resistor networks.

[0062] The present utility model also provides a transceiver device based on a gas detection instrument, Figure 3 which is a block diagram of the transceiver device of the gas detection instrument according to an embodiment of the present utility model. As Figure 3 shown, it includes:

[0063] A laser emission module 301, a detector 202, and a receiving and amplifying module 100;

[0064] The laser emission module 301 includes one laser driver and one laser, and is used to drive the laser to generate an outgoing light beam;

[0065] The detector 202 is used to receive the echo light beam of the laser and generate an echo electrical signal.

[0066] The receiving and amplifying module 100 is used to amplify the echo electrical signal, and according to the amplitude detected by the amplitude detection unit 104, the gain control circuit 102 controls the switching of N gain circuits;

[0067] Preferably, the laser is a tunable laser;

[0068] It should be noted that the detector includes but is not limited to PD, APD, SiPM, SPAD, and the present utility model does not limit it;

[0069] The transceiver device 300 based on the gas detection instrument further includes a gas absorption cell 302, which serves as a path cavity for the gas to be measured, reflects the laser multiple times, increases the optical path of the laser, and thus improves the accuracy of gas measurement. In this case, the detector 202 is used to receive the echo light beam of the laser passing through the gas absorption cell 302.

[0070] The receiving and amplifying module and the transceiver device based on the gas detection instrument introduced in this embodiment emit laser by a tunable laser, receive the echo light beam by a detector and generate an electrical signal, then amplify it by the receiving and amplifying unit, obtain the amplitude through the amplitude detection unit, and automatically switch N - stage gains according to the size of the amplitude. When the gas concentration on - site changes or the optical path changes, the optical path of the gas detection instrument can be automatically adjusted.

[0071] Although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope defined by the claims of the present utility model.

Claims

1. A receiving and amplifying module based on a gas detection instrument, characterized in that Comprising: 1 transimpedance amplification unit, composed of 1 transimpedance amplification circuit; 1 gain control unit, including 1 gain control circuit and N gain circuits, N≥2; 1 post-stage amplification unit, composed of 1 operational amplifier circuit; 1 amplitude detection unit; The feedback of the transimpedance amplification unit is connected to the output of the gain control unit, the output of the transimpedance amplification unit is connected to the input of the post-stage amplification unit, the output of the post-stage amplification unit is connected to the input of the amplitude detection unit, and the output of the amplitude detection unit is connected to the input of the gain control unit.

2. The receiving and amplifying module of the gas detection instrument according to claim 1, characterized in that The N gain circuits at least include N-2 T-type resistor network circuits.

3. The receiving and amplifying module of the gas detection instrument according to claim 1, characterized in that, The 1 gain control circuit includes 1 multiplex decoder.

4. The receiving and amplifying module of the gas detection instrument according to claim 1, characterized in that, The 1 gain control circuit further includes N path switch circuits.

5. The receiving and amplifying module of the gas detection instrument according to claim 1, characterized in that The amplitude detection unit includes but is not limited to analog-to-digital circuit, comparator detection circuit.

6. The receiving and amplifying module of the gas detection instrument according to claim 1, characterized in that, N≤16。 7. A transceiver device based on a gas detection instrument, characterized in that, Comprising: Laser emission module, detector and the receiving and amplifying module according to any one of claims 1-5; The laser emission module includes 1 laser driver and 1 laser, for driving the laser to generate an outgoing light beam; The detector is used for receiving the echo light beam of the laser and generating an echo electrical signal; The receiving and amplifying module is used for amplifying the echo electrical signal and controlling the switching of the N gain circuits by the gain control circuit according to the amplitude detected by the amplitude detection unit.

8. The transceiver device based on a gas detection instrument according to claim 7, characterized in that, The laser is a tunable laser.

9. The transceiver device based on a gas detection instrument according to claim 7, characterized in that, The detector includes but is not limited to PD, APD, SiPM, SPAD.

10. The transceiver device based on a gas detection instrument according to claim 7, characterized in that, Also includes a gas absorption cell.

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