A high-order processing circuit for dual-mode signals
By using temperature drift compensation and high-order filtering units in the dual-mode signal high-order processing circuit, and by employing a precise virtual ground reference and weighted superposition technology, the problem of DC bias accumulation caused by temperature drift is solved, thereby improving the stability and dynamic range of the signal and reducing the risk of clipping.
Patent Information
- Application Number
- CN202620204820.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-11
- Publication Date
- 2026-11-06
- Estimated Expiration
- 2036-02-11
AI Technical Summary
In existing technologies, temperature drift compensation is often performed by the MCU after sampling, which causes the DC bias related to temperature drift to accumulate step by step in the analog front end, occupying the output swing margin, increasing the risk of clipping, and the instability of the virtual ground reference in single power supply applications affects signal consistency and dynamic range.
A dual-mode signal high-order processing circuit is adopted. A stable midpoint bias reference is provided through a precision virtual ground reference generation unit. The main signal and temperature signal are weighted and superimposed in the temperature drift compensation and high-order filtering unit. Combined with active low-pass filtering, temperature drift cancellation and high-frequency noise suppression are achieved at the hardware level.
In the analog link, effective cancellation of DC baseline drift caused by temperature drift is achieved, the effective dynamic range is extended, the risk of clipping is reduced, the stability and consistency of the signal are improved, and the dependence on subsequent amplification and sampling stages is reduced.
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Figure CN224947549U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electronic circuit technology, and in particular to a dual-mode signal high-order processing circuit with integrated hardware temperature drift compensation function, which is mainly used in precision sensor signal conditioning and biomedical signal acquisition systems. Background Technology
[0002] In precision sensing signal conditioning systems, sensors such as piezoresistive bridges typically output microvolt-level differential analog signals. These signals require differential amplification, reference biasing, and filtering / shaping before being sent to an analog-to-digital converter. To improve measurement stability, dual-mode sensing components often simultaneously output the main sensing signal and a temperature reference signal to correct for temperature-related drift. A common approach is to amplify the main signal using an instrumentation amplifier and bias it to the midpoint of a single power supply, while the temperature signal is sampled via an independent channel and compensated on the MCU side. Another approach involves introducing a virtual ground and overlay network into the analog link to achieve fusion of the two signals.
[0003] However, in existing solutions, temperature drift compensation is often performed by the MCU after sampling, or the temperature signal and the main signal are processed in separate channels and asynchronously. This can easily cause the DC bias related to temperature drift to accumulate step by step in the analog front end and occupy the output swing margin, resulting in the compression of the effective dynamic range. This increases the risk of clipping in subsequent amplification or sampling stages. In addition, in single-supply applications, if the output impedance of the virtual ground reference is too high or the stability is insufficient, it will also introduce reference drift and common-mode coupling, further affecting the linear swing and consistency of the bipolar signal around the midpoint potential.
[0004] Therefore, a circuit structure is still needed that can synchronously superimpose two signals based on a stable virtual ground reference in an analog link and perform hardware cancellation of baseline drift caused by temperature drift. In view of this, this invention proposes a high-order processing circuit for dual-mode signals to solve the above problems. Utility Model Content
[0005] To address the shortcomings of the prior art described in the background section, the present invention aims to provide a high-order processing circuit for dual-mode signals. This circuit provides a stable midpoint bias reference through a precision virtual ground reference generation unit. In the temperature drift compensation and high-order filtering unit, the ambient temperature reference signal and the pre-amplified main signal are weighted and superimposed based on a hardware analog additive topology. This reduces DC baseline drift caused by the temperature drift component in the piezoresistive analog signal, reduces the DC bias's occupancy of the dynamic range, and minimizes clipping risk. Simultaneously, it incorporates an active low-pass filter to suppress high-frequency noise, thereby improving signal stability and sampleability in single-supply precision sampling scenarios.
[0006] To achieve the above objectives, this utility model provides the following technical solution:
[0007] A high-order processing circuit for dual-mode signals includes: a dual-mode sensing and interface unit, a pre-amplifier differential amplifier unit, a precision virtual ground reference generation unit, and a temperature drift compensation and high-order filtering unit.
[0008] The dual-mode sensing and interface unit is provided with a first output terminal for outputting the main sensing signal and a second output terminal for outputting the environmental mode signal. The first output terminal includes a first signal output terminal and a second signal output terminal for outputting the differential pressure signal.
[0009] The differential input terminal of the pre-amplifier unit is connected to the first signal output terminal and the second signal output terminal respectively, and is configured to perform high-gain differential amplification on the differential pressure signal and output a pre-amplified main signal.
[0010] The temperature drift compensation and high-order filtering unit has a main signal input terminal, a compensation signal input terminal, and a synthesized output terminal; the main signal input terminal is connected to the output terminal of the pre-differential amplifier unit, and the compensation signal input terminal is connected to the second output terminal of the dual-mode sensing and interface unit through a built-in proportional adjustment network.
[0011] The precision virtual ground reference generating unit has its output terminal connected to the reference terminals of the pre-differential amplifier unit and the temperature drift compensation and high-order filtering unit, respectively, and is configured to provide a common analog bias reference voltage.
[0012] Furthermore, the dual-mode sensing and interface unit includes a bridge interface for connecting a piezoresistive bridge and a temperature signal interface for connecting a temperature-sensitive element; the bridge interface is coupled to the first output terminal, and the temperature signal interface is coupled to the second output terminal, so as to realize the independent extraction of dual-mode signals.
[0013] Furthermore, the preamplifier differential amplifier unit employs an instrumentation amplifier, whose reference voltage pin (REF) is connected to the output of the precision virtual ground reference generation unit to perform bipolar amplification based on the virtual ground potential.
[0014] Furthermore, the precision virtual ground reference generating unit includes a precision voltage divider network and a voltage follower connected to the output of the network, configured to generate and drive an intermediate potential reference with low output impedance (e.g., 1 / 2 power supply voltage).
[0015] Furthermore, the core of the temperature drift compensation and high-order filtering unit includes an analog adder circuit, which is configured to proportionally adjust the temperature signal from the second output terminal and then perform inverse weighted superposition with the main signal from the pre-differential amplifier unit to cancel the temperature drift component in the pre-amplified main signal; the analog adder circuit introduces active low-pass filtering characteristics and forms an active low-pass filter, which is used to perform low-pass filtering on the synthesized signal after temperature drift compensation to suppress high-frequency noise.
[0016] Compared with the prior art, the high-order processing circuit for dual-mode signals proposed in this utility model has the following technical effects and advantages:
[0017] By adopting the above technical solution, the temperature drift compensation and high-order filtering unit can weighted cancel the DC baseline drift related to temperature drift in the analog link, so that the output DC baseline changes more stably around the virtual ground reference voltage, thereby expanding the effective dynamic range and reducing the risk of clipping under single power supply conditions. At the same time, the circuit completes the superposition and filtering at the front end, and can obtain the temperature drift suppression effect without relying on the software calculation after sampling. It has the characteristics of short processing path, low time delay and strong anti-interference ability, thereby improving the stability and consistency in precision measurement applications. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 The overall structural block diagram of the dual-mode signal high-order processing circuit provided in the embodiment of this utility model;
[0020] Figure 2 Specific circuit schematic diagrams provided for embodiments of this utility model;
[0021] Figure 3 This is a comparison diagram of the signal waveforms before and after temperature drift compensation in the embodiments of this utility model;
[0022] 100. Dual-mode sensing and interface unit; 101. Sensor interface; 200. Pre-amplifier differential amplifier unit; 201. Instrumentation amplifier; 202. Gain setting component; 300. Temperature drift compensation and high-order filtering unit; 301. Operational amplifier; 302. Temperature compensation network; 400. Precision virtual ground reference generation unit; 401. Voltage divider network; 402. Voltage follower. Detailed Implementation
[0023] The technical solutions of the present utility model will be described in detail, clearly, and completely below with reference to the accompanying drawings of the embodiments. It should be particularly noted that the specific embodiments described below are only used to better illustrate and explain the technical solutions of the present utility model, aiming to enable those skilled in the art to better understand and implement the present utility model, and should not be construed as limiting the scope of protection of the present utility model. Without departing from the spirit and substance of the present utility model, those skilled in the art can modify, adjust, or make equivalent substitutions based on the disclosed content of the present utility model, and these should all be considered within the scope of protection of the present utility model.
[0024] See Figure 1 The area indicated by the dashed box in the figure represents the dual-mode signal high-order processing circuit provided in this embodiment of the invention. This circuit includes a dual-mode sensing and interface unit 100, a precision virtual ground reference generation unit 400, a pre-amplifier differential amplifier unit 200, and a temperature drift compensation and high-order filtering unit 300. These units are electrically coupled to form a signal processing link, used to amplify the differential pressure signal from the piezoresistive sensor, and to perform hardware cancellation of the temperature drift component using the synchronously acquired temperature signal. Simultaneously, the output signal is low-pass filtered to suppress high-frequency noise.
[0025] See Figure 2 The dual-mode sensing and interface unit 100 includes a sensor interface 101 and its peripheral anti-interference circuit. The sensor interface 101 is used to establish an electrical connection with an external dual-mode sensor assembly, which outputs two independent signals: one is a differential pressure signal characterizing the change in the pressure to be measured, and the other is a temperature signal characterizing the change in the ambient temperature.
[0026] In this embodiment, the first and second signal output terminals of the sensor interface 101 are used to output differential pressure signals SIG_OUT+ and SIG_OUT-, and are coupled to the differential input terminal of the subsequent pre-amplifier differential amplifier unit 200. The sensor interface 101 outputs a temperature voltage signal TEMP_ADC through an independent temperature signal pin, wherein the temperature voltage signal TEMP_ADC serves as the ambient temperature reference signal as described in this specification and claims. To convert the temperature-sensitive element (e.g., an NTC thermistor) into an acquireable analog voltage signal, the temperature signal pin can form a voltage divider network using pull-up or pull-down resistors, and the voltage at the voltage divider node serves as the output of the TEMP_ADC.
[0027] The TEMP_ADC temperature and voltage signal is configured as a dual-output channel: the first channel is suitable for connecting to an external analog-to-digital converter or microcontroller (MCU) to achieve temperature acquisition; the second channel is connected to the compensation signal input channel of the temperature drift compensation and high-order filtering unit 300 through a current-limiting resistor, serving as a temperature compensation reference signal. This configuration achieves physical separation and synchronous acquisition of the pressure and temperature signals, providing an input basis for subsequent hardware temperature compensation.
[0028] See Figure 2 A precision virtual ground reference generation unit 400 is used to construct a virtual ground reference potential under single-supply conditions. This unit includes a voltage divider network 401 and a voltage follower 402. The voltage divider network 401 consists of a first voltage divider resistor R6 and a second voltage divider resistor R7 connected in series, with both resistors having equal resistance values. It is used to divide the 3.3V power supply voltage by two to generate a midpoint potential of 1.65V. This midpoint potential is connected to the non-inverting input of a first operational amplifier, which uses a voltage follower configuration to form the voltage follower 402, thereby outputting a low-impedance virtual ground reference voltage REF_1.65V.
[0029] The REF_1.65V is coupled to the reference terminal REF of the pre-differential amplifier unit 200 and the non-inverting input of the temperature drift compensation and high-order filtering unit 300, respectively, to provide a common DC bias reference for each analog processing unit. The first operational amplifier can be an operational amplifier suitable for single-supply operation and capable of voltage following and impedance transformation within the supply voltage range, such as one of the operational amplifiers of the LMV358, or other operational amplifiers that meet the same operating conditions.
[0030] See Figure 2 The pre-differential amplifier unit 200 is used for primary amplification of weak differential pressure signals. The core component of this unit is the instrumentation amplifier 201. The non-inverting and inverting inputs of the instrumentation amplifier 201 are coupled to SIG_OUT+ and SIG_OUT- of the sensor interface 101, respectively. The reference voltage terminal REF of the instrumentation amplifier 201 is coupled to REF_1.65V output from the precision virtual ground reference generator 400, so that the amplified output signal oscillates around the virtual ground reference. A gain setting component 202 is connected across the gain setting pins of the instrumentation amplifier 201. The gain setting component 202 consists of a fixed resistor R3 and an adjustable potentiometer R_pot2 connected in series, used to set the amplification factor of the instrumentation amplifier 201 to adapt to piezoresistive sensors of different sensitivities. The instrumentation amplifier 201 can be a similar instrumentation amplifier device suitable for single-supply operation and with a high common-mode rejection ratio, such as the AD623; other similar devices can also be selected when the supply voltage and input / output range meet the device's operating conditions.
[0031] See Figure 2The temperature drift compensation and high-order filtering unit 300 is coupled to the output of the pre-differential amplifier unit 200 to perform temperature drift cancellation and low-pass filtering on the pre-amplified main signal. This unit is built based on the second operational amplifier 301, which is configured as an inverting adder structure and introduces active low-pass filtering characteristics through a feedback network.
[0032] Specifically, the pre-amplified main signal output from the pre-differential amplifier unit 200 is connected to the inverting input of the second operational amplifier 301 through the first input resistor R10; the temperature signal TEMP_ADC is connected to the same inverting input through the temperature input resistor R8; the non-inverting input of the second operational amplifier 301 is connected to the virtual ground reference voltage REF_1.65V. A feedback compensation resistor R12 is connected between the output of the second operational amplifier 301 and the inverting input to form a closed-loop negative feedback; a feedback capacitor C6 is connected in parallel between the output of the second operational amplifier 301 and the inverting input to reduce the feedback impedance as the frequency increases, thereby forming an active low-pass filter to attenuate the high-frequency components of the superimposed composite output signal.
[0033] In the above structure, the resistance ratio of R8 to R12 is used to adjust the amplitude of the injected temperature compensation component, and R10 is used to determine the weighting coefficient of the main signal channel. By setting the resistance ratio of the feedback compensation resistor R12 to the temperature input resistor R8, the compensation amount of the weighted temperature signal is approximately matched in amplitude with the temperature drift component in the pre-amplified main signal, but with opposite polarity, thereby achieving hardware cancellation of the temperature drift component. When the effective pressure signal amplitude at the synthesized output does not fall within the sampling range of the subsequent stage or does not meet the dynamic range utilization requirements after temperature drift cancellation, the weighting coefficient of the main signal channel is further adjusted by setting the first input resistor R10, so that the DC baseline at the synthesized output is kept near REF_1.65V and the output amplitude meets the sampling requirements of the subsequent stage. The second operational amplifier 301 can be another operational amplifier of the LMV358, or other operational amplifiers that meet the requirements of single power supply and input / output swing can be selected.
[0034] In this embodiment, to ensure that the temperature compensation and the high-order filtering unit 300 can repeatedly cancel the temperature drift component, the parameters of the temperature compensation network 302 can be set through calibration. Specifically, under the condition that the piezoresistive differential pressure signals SIG_OUT+ and SIG_OUT- remain constant, two different ambient temperature points θ1 and θ2 are selected; the DC baseline voltages V_pre(θ1) and V_pre(θ2) of the pre-amplified main signal output by the pre-amplified differential amplifier unit 200 at the two temperature points are collected, as well as the voltages V_temp(θ1) and V_temp(θ2) of the temperature voltage signal TEMP_ADC output by the temperature signal interface at the two temperature points. Using the virtual ground reference voltage REF_1.65V output by the precision virtual ground reference generation unit 400 as the DC reference, the baseline drift of the pre-amplified main signal ΔV_pre=[V_pre(θ2)-V_pre(θ1)] and the temperature signal change ΔV_temp=[V_temp(θ2)-V_temp(θ1)] are calculated.
[0035] Subsequently, based on the inverting adder structure of the second operational amplifier 301, the resistance ratio of the feedback compensation resistor R12 to the temperature input resistor R8 in the temperature compensation network 302 is adjusted so that the compensation component introduced by the temperature compensation channel is approximately matched with ΔV_pre in amplitude and opposite in polarity, thereby satisfying |K×ΔV_temp+ΔV_pre|≤ε, where K is the weighting coefficient of the temperature compensation channel and ε is the preset allowable error, for example, ε=0.05×|ΔV_pre| is taken to correspond to the ±5% error band.
[0036] It should be noted that, for the aforementioned inverting adder structure, the weighting coefficient K of the temperature compensation channel is determined by the resistance ratio of the feedback compensation resistor R12 to the temperature input resistor R8. The amplitude of K is approximately equal to R12 divided by R8, and the sign is determined by the direction of inverting superposition. Thus, the amplitude of the compensation amount can be controlled by adjusting the resistance ratio of R12 to R8.
[0037] If the amplitude and dynamic range of the main signal channel need to be adjusted simultaneously, the weighting coefficient of the main signal channel can be set through the first input resistor R10, provided that the above-mentioned offset conditions are met. After the setting is completed, the resistance ratio of the feedback compensation resistor R12 and the temperature input resistor R8 is finely adjusted according to the above calibration steps so that the DC baseline of the synthesized output terminal after temperature drift compensation is kept near the virtual ground reference voltage REF_1.65V and meets the sampling requirements of the subsequent stage.
[0038] It should be noted that, since the non-inverting input of the second operational amplifier 301 in the temperature drift compensation and high-order filter unit 300 is connected to the virtual ground reference voltage REF_1.65V, under the closed-loop negative feedback of the feedback compensation resistor R12, the potential of the inverting input of the second operational amplifier 301 is stabilized at a virtual ground node close to REF_1.65V. When the pre-amplified main signal and the temperature voltage signal are introduced into this virtual ground node through the first input resistor R10 and the temperature input resistor R8, respectively, the two signals are linearly superimposed in the form of current at this node; the second operational amplifier 301 adjusts the output to balance the superimposed current in the feedback branch, thereby forming a voltage offset at the synthesized output corresponding to the weighted superposition of the two inputs. Based on the above structural characteristics, when the pressure input remains constant while the ambient temperature changes, the change in the output DC baseline is mainly determined by two parts: "the baseline drift caused by the temperature drift of the pre-amplified main signal" and "the compensation amount after the temperature voltage signal is weighted by the resistance ratio".
[0039] Therefore, by measuring the baseline drift ΔV_pre of the pre-amplified main signal and the temperature-voltage change ΔV_temp at two temperature points respectively, and adjusting the weighting coefficient of the temperature compensation channel so that the two are approximately equal in amplitude and opposite in polarity, the temperature drift component can be canceled at the hardware level.
[0040] In this embodiment, the amplitude and dynamic range of the main signal channel are primarily determined by the weighting coefficient of the pre-amplified main signal injected into the inverting adder via R10. Therefore, the first input resistor R10 can be set preferentially based on the sensor sensitivity, the sampling range of the subsequent stage, and the desired output amplitude. After R10 is determined, the weighting coefficient of the temperature compensation channel is adjusted by fine-tuning the ratio of the feedback compensation resistor R12 to the temperature input resistor R8. This ensures that the response of the temperature compensation amount to temperature changes matches the response of the baseline drift of the pre-amplified main signal to temperature changes, thereby ensuring that the residual baseline drift after compensation meets the preset allowable error band requirements. The error band is used to characterize the unavoidable residuals caused by factors such as component tolerances, temperature and voltage nonlinearity, operational amplifier input offset, and noise in the actual circuit. For example, it can be set to within 5% of the uncompensated baseline drift to ensure a stable temperature drift suppression effect while meeting engineering feasibility requirements, and to ensure that the DC baseline at the synthesized output is kept near REF_1.65V to meet the sampling requirements of the subsequent stage.
[0041] To further verify the technical effectiveness of the dual-mode signal high-order processing circuit described in this utility model under actual working conditions, the following is combined with... Figure 3 The signal processing procedure of the circuit is described in detail:
[0042] Figure 3(a) The test condition shows that the ambient temperature rises linearly over time to simulate the temperature change process under actual working conditions. During the test, the dual-mode sensing and interface unit 100 outputs the TEMP_ADC temperature voltage signal, which is continuously input to the temperature drift compensation and high-order filtering unit 300 through the temperature input resistor R8.
[0043] Figure 3 (b) A comparative response curve of the output signal, where “uncompensated signal” represents the output state without the introduction of a temperature compensation channel; as the temperature rises, the DC baseline of the output signal drifts and deviates from the vicinity of the virtual ground reference due to the influence of the temperature coefficient of the piezoresistive element.
[0044] When the circuit of this embodiment is in operation, the temperature drift compensation and high-order filtering unit 300 linearly superimposes the main signal and the temperature signal, and weights the temperature compensation component based on the resistance ratio of the feedback compensation resistor R12 and the temperature input resistor R8, so that the compensation component and the temperature drift component are approximately matched in amplitude and opposite in polarity, thereby suppressing DC baseline drift at the synthesized output terminal; at the same time, the active low-pass characteristic formed by the feedback capacitor C6 and the feedback compensation resistor R12 attenuates high-frequency noise. Figure 3 (b) "Compensated signal" indicates the output state after temperature compensation is introduced. It can be seen that the output baseline drift amplitude is significantly reduced under the same temperature rise conditions, thereby improving the stability and sampleability of the signal.
[0045] The core improvement of this invention lies in constructing a low-cost, high-stability piezoresistive signal processing circuit by combining a composite topology of temperature drift compensation and a high-order filtering unit with synchronous signal acquisition from dual-mode sensing and a precise virtual ground reference design. Its protection scope is not limited to the specific device parameters mentioned above; all equivalent structural improvements based on the construction concept of this invention fall within the protection scope of this invention.
[0046] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A high order processing circuit for a dual mode signal, characterized by include: Dual-mode sensing and interface unit (100), pre-differential amplifier unit (200), temperature drift compensation and high-order filtering unit (300), and precision virtual ground reference generation unit (400). The dual-mode sensing and interface unit (100) is configured with a first output terminal for outputting a piezoresistive analog signal and a second output terminal for outputting an ambient temperature reference signal. The pre-amplifier differential amplifier unit (200) has its input terminal coupled to the first output terminal, and is suitable for differential amplifying the piezoresistive analog signal; The temperature drift compensation and high-order filtering unit (300) has a main signal input terminal and a compensation signal input terminal; The main signal input terminal is connected to the output terminal of the preamplifier differential amplifier unit (200), and the compensation signal input terminal is connected to the second output terminal of the dual-mode sensing and interface unit (100). The temperature drift compensation and high-order filtering unit (300) is adapted to linearly superimpose the ambient temperature reference signal of the second output terminal and the amplified piezoresistive analog signal based on a hardware analog additive topology, so as to cancel the temperature drift component in the piezoresistive analog signal. The precision virtual ground reference generating unit (400) is adapted to provide a unified virtual ground reference potential for the above-mentioned units.
2. A dual-mode signal processing circuit according to claim 1, wherein, The dual-mode sensing and interface unit (100) includes a sensor interface (101). The first output terminal includes a first signal output terminal and a second signal output terminal for outputting differential pressure signals. The first signal output terminal and the second signal output terminal are connected to the input terminal of the preamplifier differential amplifier unit (200). The temperature signal pin of the sensor interface (101) is output in two ways: one is suitable for connecting to an external analog-to-digital converter, and the other is connected to the compensation signal input terminal of the temperature drift compensation and high-order filtering unit (300) through a current-limiting resistor.
3. A dual mode signal processing circuit according to claim 1, wherein, The precision virtual ground reference generation unit (400) includes a voltage divider network (401) and a voltage follower (402). The voltage divider network (401) is adapted to divide the power supply voltage to generate an intermediate potential; The voltage follower (402) has its input terminal connected to the intermediate potential and its output terminal outputting a low-impedance virtual ground reference voltage at the intermediate potential. The virtual ground reference voltage is connected to the reference voltage terminal of the preamplifier differential amplifier unit (200) and the in-phase input terminal of the temperature drift compensation and high-order filter unit (300).
4. A dual mode signal processing circuit according to claim 1, wherein, The preamplifier differential amplifier unit (200) includes an instrumentation amplifier (201) and a gain setting component (202). The non-inverting input terminal and the inverting input terminal of the instrumentation amplifier (201) are respectively coupled to the first signal output terminal and the second signal output terminal of the dual-mode sensing and interface unit (100) for outputting differential pressure signals; The gain setting component (202) is connected across the gain setting pins of the instrumentation amplifier (201).
5. A dual mode signal processing circuit according to claim 4, wherein, The gain setting component (202) consists of a fixed resistor (R3) and an adjustable potentiometer (R_pot2) connected in series.
6. A dual mode signal processing circuit according to claim 1, wherein, The temperature drift compensation and high-order filtering unit (300) includes an operational amplifier (301) and a temperature compensation network (302). The operational amplifier (301) is configured as an inverting adder structure; The output signal of the pre-differential amplifier unit (200) is connected to the inverting input terminal of the operational amplifier (301) through the first input resistor (R10); The ambient temperature reference signal output by the dual-mode sensing and interface unit (100) is connected to the same inverting input terminal of the operational amplifier (301) through the temperature compensation network (302).
7. A dual mode signal processing circuit according to claim 6, wherein, The temperature compensation network (302) includes a temperature input resistor (R8) and a feedback compensation resistor (R12). The ambient temperature reference signal output by the dual-mode sensing and interface unit (100) is connected to the inverting input terminal of the operational amplifier (301) through the temperature input resistor (R8); The resistance ratio of the feedback compensation resistor (R12) to the temperature input resistor (R8) is configured such that the amplitude of the injected temperature reference signal matches the amplitude of the temperature drift component in the piezoresistive analog signal. The operational amplifier (301) has a feedback compensation resistor (R12) and a feedback capacitor (C6) connected in parallel between its inverting input terminal and its output terminal, in order to cooperate with the first input resistor (R10) to form an active low-pass filter.