Signal processing circuit of low-temperature drift interference type sensor

Abstract

The utility model discloses a signal processing circuit of a low-temperature drift interference type sensor. The signal processing circuit comprises a first signal amplification module, a second amplification module, a third amplification module and a fourth amplification module, the input end of the first amplification module is used for being connected to the output end of an external sensor, the output end of the first amplification module is connected to the input end of the second amplification module, the output end of the second amplification module is connected to the input end of the third amplification module, and the output end of the third amplification module is connected to the input end of the fourth amplification module; the second amplification module comprises an amplifier U2, an encoder SW2, a capacitor C6, a capacitor C7, a capacitor C8, a resistor R4, a resistor R9, a resistor R10, a resistor R11, a sliding resistor R24 and a resistor module. The low-temperature drift interference type sensor signal processing circuit solves the problem that in the prior art, due to the fact that partial voltage needs to be adjusted by adjusting a rheostat, temperature drift affects unreliable output signals.

Description

Technical Field

[0001] The utility model relates to a signal processing circuit, in particular to a low temperature drift interference type sensor signal processing circuit. Background Art

[0002] Pressure sensors are widely used in industries such as industry, automobiles, home appliances, and robots. They can be used to detect pressure sensing information in various mechanical structures (such as automobile manufacturing, rotors in motors, cylinder stamping, etc.). The output signal of a typical pressure sensing circuit is weak, and most of them cannot be directly transmitted to display, recording, or analysis instruments. They need to be further amplified and subjected to impedance conversion. Therefore, a sensor signal processing circuit with amplification function is required.

[0003] In the prior art, the sensor signal processing circuit includes: a first-stage amplification module, a second-stage amplification module and a third-stage amplification module. The output end of the first-stage amplification module is connected to the input end of the second-stage amplification module, the output end of the second-stage amplification module is connected to the input end of the third-stage amplification module, and the output end of the third-stage amplification module is the output end of the sensor signal processing circuit. A variable resistor is arranged in the second-stage amplification module, and the output signal size is adjusted by adjusting the variable resistor. However, when the voltage needs to change significantly, temperature drift will occur if only the variable resistor is used for adjustment, resulting in the output signal size after adjustment failing to reach the set value. Utility Model Content

[0004] The utility model provides a low temperature drift interference sensor signal processing circuit to solve the problem in the prior art that the output signal is unreliable due to temperature drift caused by adjusting the voltage division size by adjusting the variable resistor.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] The utility model discloses a low temperature drift interference sensor signal processing circuit, comprising: a first signal amplifying module, a second amplifying module, a third amplifying module and a fourth amplifying module; the input end of the first amplifying module is used to connect to the output end of the external sensor, the output end of the first amplifying module is connected to the input end of the second amplifying module, the output end of the second amplifying module is connected to the input end of the third amplifying module, and the output end of the third amplifying module is connected to the input end of the fourth amplifying module; the second amplifying module comprises: an amplifier U2, an encoder SW2, a capacitor C6, a capacitor C7, a capacitor C8, a resistor R4, a resistor R9, a resistor R10, a resistor R11, a sliding resistor R24 ​​and a resistor module, one end of the resistor R4 is the input end of the second amplifying module, the other end of the resistor R4 is respectively connected to the in-phase input end of the amplifier U2 and the positive electrode of the capacitor C6, and the resistor module The negative pole of capacitor C6 is grounded, the output end of amplifier U2 is connected to one end of resistor R9, the connection point between amplifier U2 and resistor R9 is connected to the positive pole of capacitor C7, the negative pole of capacitor C7 is connected to the other end of resistor R9, the connection point between resistor R9 and the negative pole of capacitor C7 is connected to one end of resistor R10, the other end of resistor R10 is connected to the sliding end of sliding resistor R24, the inverting input end of amplifier U2 is connected to the output end C of encoder SW2, the input end of encoder SW2 is connected to one end of the resistor module, the other end of the resistor module and one end of the sliding resistor R24 ​​are both grounded, the other end of the sliding resistor R24 ​​is connected to one end of resistor R11, the connection point between sliding resistor R24 ​​and resistor R11 is connected to the positive pole of capacitor C7, the other end of resistor R11 is connected to the positive pole of capacitor C8, the negative pole of capacitor C8 is grounded, and the connection point between resistor R11 and sliding resistor R24 ​​is the output end of the second amplification module.

[0007] Preferably, the first amplification module includes: an encoder SW1, a capacitor group, a resistor R1, a resistor R2, a resistor R3 and an amplifier U1, one end of the resistor R1 is the input end of the first amplification module, the other end of the resistor R1 is connected to the positive electrode of the capacitor group, the negative electrode of the capacitor group is connected to the input end of the encoder SW1, the output end C of the encoder SW1 is the output end of the first amplification module, the connection point between the resistor R1 and the capacitor group is connected to one end of the resistor R3 and the inverting input end of the amplifier U1, the output end of the amplifier U1 and the other end of the resistor R3 are both connected to the output end of the encoder SW1, the in-phase input end of the amplifier U1 is connected to one end of the resistor R2, and the other end of the resistor R2 is grounded.

[0008] Preferably, the third amplification module includes: resistor R12, resistor R13, resistor R14, resistor R15, resistor R16, resistor R17, resistor R18, resistor R19, resistor R20, capacitor C9, amplifier U3, controllable single-pole multi-throw module SW3, transistor Q1, diode D1 and diode D2, one end of resistor R12 is the input end of the third amplification module, the other end of resistor R12 is connected to the positive electrode of capacitor C9, one end of resistor R14 and one end of resistor R15, the negative electrode of capacitor C9 and the other end of resistor R14 are grounded, the other end of resistor R15 is connected to one end of resistor R13, the other end of resistor R13 is connected to the fixed end of single-pole multi-throw module SW3, and the single-pole multi-throw module SW 3 is grounded, the second moving end of the single-pole multi-throw module SW3 is grounded through a resistor R16, the third moving end of the single-pole multi-throw module SW3 is connected to one end of a resistor R17, the third moving end of the single-pole multi-throw module SW3 is connected to the inverting input end of the amplifier U3, the other end of the resistor R17 is connected to the emitter of the transistor Q1, the emitter of the transistor Q1 is grounded through a resistor R20, the output end of the amplifier U3 is connected to the base of the transistor Q1 through a resistor R18, the collector of the transistor Q1 is connected to the cathode of the diode D2 through a resistor R19, the anode of the diode D2 is connected to the cathode of the diode D1, the anode of the diode D1 is used to be connected to an external positive power supply, and the collector of the transistor Q1 is the output end of the third amplifier module.

[0009] Preferably, the fourth amplification module includes: a transistor Q2, a resistor R21, a resistor R22, a resistor R23, a capacitor C10, a capacitor C11, a capacitor C12, an amplifier U4 and a diode D3, the same-direction input end of the amplifier U4 is the input end of the fourth amplification module, the inverting input end of the amplifier U4 is connected to the cathode of the diode D2 through the resistor R21, the inverting input end of the amplifier U4 is connected to the emitter of the transistor Q2, the high-voltage power supply end of the amplifier U4 is connected to the external positive power supply, the high-voltage power supply end of the amplifier U4 is connected to the positive electrode of the capacitor C10, the negative electrode of the capacitor C10 is grounded, the low-voltage power supply end of the amplifier U4 is connected to the positive electrode of the capacitor C11 and the external negative power supply, the negative electrode of the capacitor C11 is grounded, the output end of the amplifier U4 is connected to the base of the transistor Q2 through the resistor R23, the collector of the transistor Q2 is connected to the anode of the diode D3, the cathode of the diode D3 is connected to one end of the resistor R22 and the positive electrode of C12, and the other end of the resistor R22 and the negative electrode of C12 are both grounded.

[0010] Preferably, the capacitor group includes: capacitor C1, capacitor C2, capacitor C3, capacitor C4 and capacitor C5, the connection point of resistor R1 and resistor R3 is connected to the positive electrode of capacitor C1, the positive electrode of capacitor C2, the positive electrode of capacitor C3, the positive electrode of capacitor C4 and the positive electrode of capacitor C1, the cathode of capacitor C1 is connected to the first input terminal of encoder SW1, the cathode of capacitor C2 is connected to the second input terminal of encoder SW1, the cathode of capacitor C3 is connected to the third input terminal of encoder SW1, the cathode of capacitor C4 is connected to the fourth input terminal of encoder SW1, and the output terminal C of encoder SW1 is connected to the cathode of capacitor C5.

[0011] Preferably, the resistance module includes: resistor R5, resistor R6, resistor R7 and resistor R8, the first input end of the encoder SW2 is connected to one end of the resistor R5, the second input end of the encoder SW2 is connected to one end of the resistor R6, the third input end of the encoder SW2 is connected to one end of the resistor R7, the fourth input end of the encoder SW2 is connected to one end of the resistor R8, and the other end of the resistor R5, the other end of the resistor R6, the other end of the resistor R7 and the other end of the resistor R8 are all grounded.

[0012] Compared with the prior art, the utility model has the following beneficial effects:

[0013] In the present application, the signal output from the sensor output terminal SIn is amplified in four stages so that the signal can be identified. The voltage output value needs to be adjusted at the output end of the second amplifier module. Under the current circumstances, the voltage output value is generally adjusted by adjusting the resistance of the sliding rheostat. Due to the large temperature drift, the voltage output value is not the set value. Therefore, in the present application, the encoder SW2 and the sliding resistor R24 ​​are used to adjust the voltage output value. The encoder SW2 is used to achieve coarse adjustment. The resistors R5, R6, R7 and R8 have different voltage values. The voltage value of the input end of the amplifier U2 is UA, and the output voltage of the output end of the amplifier U2 is UB. UB is also the output voltage value of the second amplifier module. The amplifier U2 is a common-mode amplifier. The resistance value of the R10, R24 parts and the resistance module in parallel is Rx, then UB is equal to UA*(1+R9 / Rx). It can be seen that the sliding resistor The voltage value connected to the moving resistor R24 ​​affects Rx. At the same time, Rx will also change after any of the resistors R5, R6, R7 and R8 (the resistance values ​​of resistors R5, R6, R7 and R8 are different) in the resistor module are connected. In this application, the encoder SW2 is used to connect any one or more of the resistors R5, R6, R7 and R8 with different resistance values, so as to achieve a larger adjustment of Rx. After the large adjustment, the sliding resistor R24 ​​is used to make a small adjustment, so as to achieve the purpose of regulating the output voltage UB. The encoder SW2 is used to connect any one or more of the resistors R5, R6, R7 and R8 with different resistance values, which will not be affected by temperature drift, and the temperature drift has little effect on the sliding resistor R24 ​​with small resistance adjustment, thereby reducing the influence of temperature drift on the output voltage UB, improving the accuracy of the output voltage UB, and meeting the requirements more.

[0014] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a circuit diagram of the first amplification module in the low temperature drift interference sensor signal processing circuit.

[0016] Figure 2 This is a circuit diagram of the second amplification module in the low-temperature drift interference sensor signal processing circuit.

[0017] Figure 3 It is a circuit diagram of the third amplification module and the fourth amplification module in the low temperature drift interference sensor signal processing circuit. DETAILED DESCRIPTION

[0018] In order to make the technical means, creative features, objectives and functions of the present invention clearer and easier to understand, the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods:

[0019] like Figures 1 to 3 As shown, the utility model discloses a low-temperature drift interference sensor signal processing circuit, including: a first signal amplifying module, a second amplifying module, a third amplifying module and a fourth amplifying module; the input end of the first amplifying module is used to connect to the output end SIn of the external sensor, the output end of the first amplifying module is connected to the input end of the second amplifying module, the output end of the second amplifying module is connected to the input end of the third amplifying module, and the output end of the third amplifying module is connected to the input end of the fourth amplifying module; the second amplifying module includes: an amplifier U2, an encoder SW2, a capacitor C6, a capacitor C7, a capacitor C8, a resistor R4, a resistor R9, a resistor R10, a resistor R11, a sliding resistor R24 ​​and a resistor module, one end of the resistor R4 is the input end of the second amplifying module, and the other end of the resistor R4 is respectively connected to the in-phase input end of the amplifier U2 and the positive input end of the capacitor C6 The negative electrode of capacitor C6 is grounded, the output end of amplifier U2 is connected to one end of resistor R9, the connection point between amplifier U2 and resistor R9 is connected to the positive electrode of capacitor C7, the negative electrode of capacitor C7 is connected to the other end of resistor R9, the connection point between resistor R9 and the negative electrode of capacitor C7 is connected to one end of resistor R10, the other end of resistor R10 is connected to the sliding end of sliding resistor R24, the inverting input end of amplifier U2 is connected to the output end C of encoder SW2, the input end of encoder SW2 is connected to one end of the resistor module, the other end of the resistor module and one end of the sliding resistor R24 ​​are both grounded, the other end of the sliding resistor R24 ​​is connected to one end of resistor R11, the connection point between sliding resistor R24 ​​and resistor R11 is connected to the positive electrode of capacitor C7, the other end of resistor R11 is connected to the positive electrode of capacitor C8, the negative electrode of capacitor C8 is grounded, and the connection point between resistor R11 and sliding resistor R24 ​​is the output end of the second amplification module.

[0020] The first amplification module includes: encoder SW1, capacitor group, resistor R1, resistor R2, resistor R3 and amplifier U1, one end of resistor R1 is the input end of the first amplification module, the other end of resistor R1 is connected to the positive electrode of the capacitor group, the negative electrode of the capacitor group is connected to the input end of encoder SW1, the output end C of encoder SW1 is the output end of the first amplification module, the connection point between resistor R1 and the capacitor group is connected to one end of resistor R3 and the inverting input end of amplifier U1, the output end of amplifier U1 and the other end of resistor R3 are both connected to the output end of encoder SW1, the in-phase input end of amplifier U1 is connected to one end of resistor R2, and the other end of resistor R2 is grounded. There are 7 capacitors of different sizes in the capacitor group, and different capacitors can be adjusted and connected through encoder SW1.

[0021] The third amplification module includes: resistor R12, resistor R13, resistor R14, resistor R15, resistor R16, resistor R17, resistor R18, resistor R19, resistor R20, capacitor C9, amplifier U3, controllable single-pole multi-throw module SW3, transistor Q1, diode D1 and diode D2, one end of resistor R12 is the input end of the third amplification module, the other end of resistor R12 is connected to the positive electrode of capacitor C9, one end of resistor R14 and one end of resistor R15, the negative electrode of capacitor C9 and the other end of resistor R14 are grounded, the other end of resistor R15 is connected to one end of resistor R13, the other end of resistor R13 is connected to the fixed end of single-pole multi-throw module SW3, and the third amplification module of single-pole multi-throw module SW3 is connected to the fixed end of single-pole multi-throw module SW3. One moving end is grounded, the second moving end of the single-pole multi-throw module SW3 is grounded through a resistor R16, the third moving end of the single-pole multi-throw module SW3 is connected to one end of a resistor R17, the third moving end of the single-pole multi-throw module SW3 is connected to the inverting input end of the amplifier U3, the other end of the resistor R17 is connected to the emitter of the transistor Q1, the emitter of the transistor Q1 is grounded through a resistor R20, the output end of the amplifier U3 is connected to the base of the transistor Q1 through a resistor R18, the collector of the transistor Q1 is connected to the cathode of the diode D2 through a resistor R19, the anode of the diode D2 is connected to the cathode of the diode D1, the anode of the diode D1 is used to connect to the external positive power supply, and the collector of the transistor Q1 is the output end of the third amplifier module. After the second amplifier module outputs the output voltage UB, it is stepped down at the resistor R12, and then the resistor R15, R13 and the sub-circuit connected to SW3 form a divided voltage UC, which reaches the input end of the third amplifier module, and the sub-circuit connected to W3 affects the UC value, thereby achieving further voltage regulation and will not be affected by temperature drift.

[0022] The fourth amplification module includes: transistor Q2, resistor R21, resistor R22, resistor R23, capacitor C10, capacitor C11, capacitor C12, amplifier U4 and diode D3, the same-direction input end of amplifier U4 is the input end of the fourth amplification module, the inverting input end of amplifier U4 is connected to the cathode of diode D2 through resistor R21, the inverting input end of amplifier U4 is connected to the emitter of transistor Q2, the high-voltage power supply end of amplifier U4 is connected to the external positive power supply, the high-voltage power supply end of amplifier U4 is connected to the positive electrode of capacitor C10, the negative electrode of capacitor C10 is grounded, the low-voltage power supply end of amplifier U4 is connected to the positive electrode of capacitor C11 and the external negative power supply, the negative electrode of capacitor C11 is grounded, the output end of amplifier U4 is connected to the base of transistor Q2 through resistor R23, the collector of transistor Q2 is connected to the anode of diode D3, the cathode of diode D3 is connected to one end of resistor R22 and the positive electrode of C12, and the other end of resistor R22 and the negative electrode of C12 are both grounded. Transistor Q1 and transistor Q2 both amplify signals and also act as switches.

[0023] The capacitor group includes: capacitor C1, capacitor C2, capacitor C3, capacitor C4 and capacitor C5. The connection point of resistor R1 and resistor R3 is connected to the positive electrode of capacitor C1, the positive electrode of capacitor C2, the positive electrode of capacitor C3, the positive electrode of capacitor C4 and the positive electrode of capacitor C1. The cathode of capacitor C1 is connected to the first input terminal of encoder SW1, the cathode of capacitor C2 is connected to the second input terminal of encoder SW1, the cathode of capacitor C3 is connected to the third input terminal of encoder SW1, the cathode of capacitor C4 is connected to the fourth input terminal of encoder SW1, and the output terminal C of encoder SW1 is connected to the cathode of capacitor C5.

[0024] The resistor module includes: resistor R5, resistor R6, resistor R7 and resistor R8. The first input end of the encoder SW2 is connected to one end of the resistor R5, the second input end of the encoder SW2 is connected to one end of the resistor R6, the third input end of the encoder SW2 is connected to one end of the resistor R7, the fourth input end of the encoder SW2 is connected to one end of the resistor R8, and the other end of the resistor R5, the other end of the resistor R6, the other end of the resistor R7 and the other end of the resistor R8 are all grounded.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. Low temperature drift interference sensor signal processing circuit, It is characterized in that include: A first signal amplifying module, a second amplifying module, a third amplifying module and a fourth amplifying module; The input end of the first amplifying module is used to connect to the output end of the external sensor, the output end of the first amplifying module is connected to the input end of the second amplifying module, the output end of the second amplifying module is connected to the input end of the third amplifying module, and the output end of the third amplifying module is connected to the input end of the fourth amplifying module; The second amplifying module includes: an amplifier U2, an encoder SW2, a capacitor C6, a capacitor C7, a capacitor C8, a resistor R4, a resistor R9, a resistor R10, a resistor R11, a sliding resistor R24 ​​and a resistor module, one end of the resistor R4 is the input end of the second amplifying module, the other end of the resistor R4 is connected to the in-phase input end of the amplifier U2 and the positive electrode of the capacitor C6, the negative electrode of the capacitor C6 is grounded, the output end of the amplifier U2 is connected to one end of the resistor R9, the connection point between the amplifier U2 and the resistor R9 is connected to the positive electrode of the capacitor C7, the negative electrode of the capacitor C7 is connected to the other end of the resistor R9, and the connection point between the resistor R9 and the negative electrode of the capacitor C7 is connected. The line point is connected to one end of resistor R10, and the other end of resistor R10 is connected to the sliding end of sliding resistor R24. The inverting input end of amplifier U2 is connected to the output end C of encoder SW2. The input end of encoder SW2 is connected to one end of the resistor module. The other end of the resistor module and one end of the sliding resistor R24 ​​are both grounded. The other end of the sliding resistor R24 ​​is connected to one end of resistor R11. The connection point between sliding resistor R24 ​​and resistor R11 is connected to the positive electrode of capacitor C7. The other end of resistor R11 is connected to the positive electrode of capacitor C8. The negative electrode of capacitor C8 is grounded. The connection point between resistor R11 and sliding resistor R24 ​​is the output end of the second amplification module.

2. The low temperature drift interference sensor signal processing circuit according to claim 1, It is characterized in that The first amplification module includes: an encoder SW1, a capacitor group, a resistor R1, a resistor R2, a resistor R3 and an amplifier U1, one end of the resistor R1 is the input end of the first amplification module, the other end of the resistor R1 is connected to the positive electrode of the capacitor group, the negative electrode of the capacitor group is connected to the input end of the encoder SW1, the output end C of the encoder SW1 is the output end of the first amplification module, the connection point between the resistor R1 and the capacitor group is connected to one end of the resistor R3 and the inverting input end of the amplifier U1, the output end of the amplifier U1 and the other end of the resistor R3 are both connected to the output end of the encoder SW1, the in-phase input end of the amplifier U1 is connected to one end of the resistor R2, and the other end of the resistor R2 is grounded.

3. The low temperature drift interference sensor signal processing circuit according to claim 2, It is characterized in that The third amplification module includes: resistor R12, resistor R13, resistor R14, resistor R15, resistor R16, resistor R17, resistor R18, resistor R19, resistor R20, capacitor C9, amplifier U3, controllable single-pole multi-throw module SW3, transistor Q1, diode D1 and diode D2, one end of resistor R12 is the input end of the third amplification module, the other end of resistor R12 is connected to the positive electrode of capacitor C9, one end of resistor R14 and one end of resistor R15, the negative electrode of capacitor C9 and the other end of resistor R14 are grounded, the other end of resistor R15 is connected to one end of resistor R13, the other end of resistor R13 is connected to the fixed end of single-pole multi-throw module SW3, and the third amplification module of single-pole multi-throw module SW3 is connected to the fixed end of single-pole multi-throw module SW3. One moving end is grounded, the second moving end of the single-pole multi-throw module SW3 is grounded through a resistor R16, the third moving end of the single-pole multi-throw module SW3 is connected to one end of a resistor R17, the third moving end of the single-pole multi-throw module SW3 is connected to the inverting input end of the amplifier U3, the other end of the resistor R17 is connected to the emitter of the transistor Q1, the emitter of the transistor Q1 is grounded through a resistor R20, the output end of the amplifier U3 is connected to the base of the transistor Q1 through a resistor R18, the collector of the transistor Q1 is connected to the cathode of the diode D2 through a resistor R19, the anode of the diode D2 is connected to the cathode of the diode D1, the anode of the diode D1 is used to connect to an external positive power supply, and the collector of the transistor Q1 is the output end of the third amplifier module.

4. The low temperature drift interference sensor signal processing circuit according to claim 3, It is characterized in that The fourth amplification module includes: transistor Q2, resistor R21, resistor R22, resistor R23, capacitor C10, capacitor C11, capacitor C12, amplifier U4 and diode D3, the same-direction input end of amplifier U4 is the input end of the fourth amplification module, the inverting input end of amplifier U4 is connected to the cathode of diode D2 through resistor R21, the inverting input end of amplifier U4 is connected to the emitter of transistor Q2, the high-voltage power supply end of amplifier U4 is connected to the external positive power supply, the high-voltage power supply end of amplifier U4 is connected to the positive electrode of capacitor C10, the negative electrode of capacitor C10 is grounded, the low-voltage power supply end of amplifier U4 is connected to the positive electrode of capacitor C11 and the external negative power supply, the negative electrode of capacitor C11 is grounded, the output end of amplifier U4 is connected to the base of transistor Q2 through resistor R23, the collector of transistor Q2 is connected to the anode of diode D3, the cathode of diode D3 is connected to one end of resistor R22 and the positive electrode of C12, and the other end of resistor R22 and the negative electrode of C12 are both grounded.

5. The low temperature drift interference sensor signal processing circuit according to claim 4, It is characterized in that The capacitor group includes: capacitor C1, capacitor C2, capacitor C3, capacitor C4 and capacitor C5. The connection point of resistor R1 and resistor R3 is connected to the positive electrode of capacitor C1, the positive electrode of capacitor C2, the positive electrode of capacitor C3, the positive electrode of capacitor C4 and the positive electrode of capacitor C1. The cathode of capacitor C1 is connected to the first input terminal of encoder SW1, the cathode of capacitor C2 is connected to the second input terminal of encoder SW1, the cathode of capacitor C3 is connected to the third input terminal of encoder SW1, the cathode of capacitor C4 is connected to the fourth input terminal of encoder SW1, and the output terminal C of encoder SW1 is connected to the cathode of capacitor C5.

6. The low temperature drift interference sensor signal processing circuit according to claim 5, It is characterized in that The resistor module includes: resistor R5, resistor R6, resistor R7 and resistor R8. The first input end of the encoder SW2 is connected to one end of the resistor R5, the second input end of the encoder SW2 is connected to one end of the resistor R6, the third input end of the encoder SW2 is connected to one end of the resistor R7, the fourth input end of the encoder SW2 is connected to one end of the resistor R8, and the other end of the resistor R5, the other end of the resistor R6, the other end of the resistor R7 and the other end of the resistor R8 are all grounded.

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