Vibration cylinder pressure sensor signal amplification circuit and vibration cylinder pressure sensor

Abstract

The invention belongs to the technical field of sensor signal amplification, and discloses a vibration cylinder pressure sensor signal amplification circuit and a vibration cylinder pressure sensor.The vibration cylinder pressure sensor signal amplification circuit comprises a filter circuit, a gain adjusting circuit, a phase adjusting circuit, an amplitude limiting circuit, a frequency detection circuit and a temperature detection circuit; amplitude adjustment of a certain gain is achieved through a gain adjusting circuit, a gain amplification signal VB is obtained and input to a phase adjusting circuit and a frequency detection circuit, the phase adjusting circuit outputs a square wave signal VC and inputs the square wave signal VC to an amplitude limiting circuit, and the amplitude limiting circuit outputs an amplitude limiting square wave signal VD and loads the amplitude limiting square wave signal VD to a vibration cylinder; a gain amplification signal VB output by the gain adjusting circuit passes through the frequency detection circuit, a square wave frequency signal VO is output, a closed-loop control system is formed to achieve driving and detection of the resonance cylinder pressure sensor, and the actual frequency of the vibration cylinder body depends on the sensed pressure.

Description

Technical Field

[0001] The invention belongs to the technical field of sensor signal amplification, and relates to a vibration cylinder pressure sensor signal amplification circuit and a vibration cylinder pressure sensor. Background Art

[0002] A sensor is a device or apparatus that can convert specific measured information (such as physical quantity, chemical quantity, biomass, etc.) into a usable signal according to a certain rule. Vibrating cylinder pressure sensors are widely used in aerospace and other fields due to their high precision, good stability, high sensitivity, good integration, and simple structure. When the air pressure changes, the vibrating cylinder deforms, which in turn changes the stiffness of the resonator, causing the resonant frequency of the vibrating cylinder resonator to change. The current air pressure value can be obtained by measuring the resonant frequency. However, the output signal of the pressure sensor that detects pressure changes is generally a weak signal at the millivolt level, which is not convenient for subsequent analysis and application. Therefore, it is necessary to design a signal amplification circuit for the pressure sensor to amplify and filter the sensor output signal.

[0003] The sensor signal amplification circuit is mainly used in the resonant cylinder pressure sensor. Together with the vibration cylinder, it forms a closed-loop control system to realize the drive and detection of the resonant pressure sensor. The actual frequency of the vibration cylinder depends on the pressure felt. When the measured pressure changes and causes the resonant frequency of the resonant pressure sensor to change, the self-excited closed-loop control system can quickly lock the resonant frequency at the oscillation frequency through noise excitation and output it as an output signal. The measured pressure is measured by observing the change in the output signal frequency of the sensor signal amplification circuit.

[0004] The working principle diagram of the vibration cylinder sensor is as follows Figure 1 As shown. When the vibration tube in the sensor is working, it is maintained in a resonant state under the action of the sensor signal amplification circuit and the electromagnetic excitation / pickup system. When the vibration tube is subjected to pressure, the wall of the vibration tube is subjected to tensile stress, which increases the load and causes the resonant frequency to increase. The sensor signal amplification circuit outputs a square wave frequency signal and an analog temperature signal of the vacuum tube.

[0005] At present, there is no signal amplification circuit for a vibration cylinder pressure sensor that forms a closed-loop control system with the vibration cylinder to realize the driving and detection of the resonant pressure sensor and output a square wave frequency signal and a temperature detection signal at the same time. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a vibrating cylinder pressure sensor signal amplifying circuit and a vibrating cylinder pressure sensor, so as to solve the technical problem that there is no signal amplifying circuit for a vibrating cylinder pressure sensor in the prior art, which forms a closed-loop control system with the vibrating cylinder to realize the driving and detection of the resonant pressure sensor and output a square wave frequency signal and a temperature detection signal.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] The present invention provides a vibration cylinder pressure sensor signal amplification circuit, comprising a filter circuit, a gain adjustment circuit, a phase adjustment circuit, a limiter circuit, a frequency detection circuit and a temperature detection circuit; the filter circuit is used to amplify the vibration pickup signal V output by the vibration cylinder. IN After filtering, the signal after filtering is a sinusoidal signal V A , input to the input end of the gain adjustment circuit; the gain adjustment circuit is for the input sinusoidal signal V A Amplify the signal V B Input to the phase adjustment circuit and the frequency detection circuit; the phase adjustment circuit amplifies the gain signal V B Perform DC isolation processing to obtain a square wave signal V C And input to the limiting circuit, the limiting circuit is the square wave signal V C To limit the amplitude, the amplitude-limited square wave signal V D Input to the vibration tube, the vibration tube outputs the vibration pickup signal V IN The input is sent to the filter circuit, and the temperature detection circuit detects the temperature of the vibration tube and outputs the temperature detection signal V T The frequency detection circuit amplifies the signal V B Perform frequency detection and output square wave frequency signal V O .

[0009] Furthermore, the filter circuit includes resistors R1 to R6, capacitors C1 to C3, capacitor C10 and operational amplifier U1; one end of the resistor R1 is connected to the vibration pickup signal V IN The other end of the resistor R4 is connected to the resistor R5 and the capacitor C10, the other end of the capacitor C10 is connected to the ground, the other end of the resistor R5 is connected to the output of the operational amplifier U1, the non-inverting end of the operational amplifier U1 is connected to the ground, the other end of the resistor R4 is connected to the resistor R5 and the capacitor C10, the other end of the capacitor C10 is connected to the ground, and the other end of the resistor R5 is connected to the output of the operational amplifier U1.

[0010] Furthermore, the gain adjustment circuit includes resistors R7-R8 and an operational amplifier U2; one end of the resistor R7 is connected to the output end of the operational amplifier U1, and the other end is connected to the resistor R8 and the inverting end of the operational amplifier U2; the other end of the resistor R8 is connected to the output end of the operational amplifier U2.

[0011] Furthermore, the phase adjustment circuit includes resistors R9-R12, capacitor C4, diodes D1-D5 and operational amplifier U3; one end of the capacitor C4 is connected to the output end of the operational amplifier U2, and the other end is connected to the resistor R11, the other end of the resistor R11 is connected to one end of the resistor R12, the inverting end of the operational amplifier U3, the cathode of the diode D1, and the anode of the diode D4, the in-phase end of the operational amplifier U3 is connected to the resistor R9 and the resistor R10, and the other end of the resistor R9 is connected to the power supply V CC The other end of the resistor R10 is connected to the ground, the anode of the diode D1 is connected to the cathode of the diode D2, the anode of the diode D2 is connected to the cathode of the diode D3, the cathode of the diode D4 is connected to the anode of the diode D5 and is connected to the ground, and the anode of the diode D3 and the cathode of the diode D5 are connected to the output end of the operational amplifier U3.

[0012] Furthermore, the limiting circuit includes resistors R13 to R16, a capacitor C5, a diode D6 and a transistor Q1; one end of the resistor R13 is connected to the output end of the operational amplifier U3, and the other end is connected to the base of the transistor Q1; the other end of the resistor R12 is connected to the emitter of the transistor Q1 and one end of the resistor R16; the other end of the resistor R16 is connected to the ground; the collector of the transistor Q1 is connected to one end of the resistor R15, one end of the capacitor C5, and the cathode of the diode D6; the other end of the capacitor C5 is connected to the ground with the anode of the diode D6; the other end of the resistor R15 is connected to one end of the resistor R14; and the other end of the resistor R14 is connected to the power supply V CC .

[0013] Furthermore, the frequency detection circuit includes resistors R17 to R23, capacitors C6 to C9, an operational amplifier U4 and a comparator U5; the inverting end of the operational amplifier U4, one end of the resistor R17, and one end of the capacitor C6 are connected to the output end of the operational amplifier U2, the other end of the resistor R17 is connected to one end of the resistor R18 and one end of the capacitor C7, the other end of the capacitor C7 is connected to the ground, the other end of the capacitor C6 and the other end of the resistor R8 are connected to the output end of the operational amplifier U4, and the in-phase end of the operational amplifier U4 is grounded. The output end of the operational amplifier U4 is connected to one end of the capacitor C8, the other end of the capacitor C8 is connected to one end of the resistor R19 and one end of the resistor R20, the other end of the resistor R20 is connected to the capacitor C9 and the inverting end of the comparator U5, the other end of the resistor R19 and the other end of the capacitor C9 are connected to the ground, the in-phase end of the comparator U5 is connected to one end of the resistor R22 and the resistor R23, the other end of the resistor R23 is connected to the ground, the resistor R22 is connected to the output end of the comparator U5 and one end of the resistor R21, and the other end of the resistor R21 is connected to the power supply V CC .

[0014] Furthermore, the temperature detection circuit includes resistors R24-R29, diodes D7-D8 and an operational amplifier U6; the anode of the diode D8 is connected to one end of the resistor R29 and one end of the resistor R24, the other end of the resistor R24 ​​is connected to one end of the resistor R25 and the in-phase end of the operational amplifier U6, the other end of the resistor R29 is connected to one end of the resistor R28 and the cathode of the diode D7, and the other end of the resistor R28 is connected to the power supply V CC The anode of diode D7, the cathode of diode D8, and the other end of resistor R25 are connected to the ground, the inverting end of operational amplifier U6 is connected to one end of resistor R26 and one end of resistor R27, the other end of resistor R27 is connected to the ground, and the other end of resistor R26 is connected to the output end of operational amplifier U6.

[0015] Furthermore, the gain factor of the gain adjustment circuit is determined by the value of resistor R8 divided by the value of resistor R7.

[0016] Furthermore, the comparator U5 includes LM111 and LM139; the operational amplifiers U1 to U4 and U6 include TL062 and TL082.

[0017] The present invention also provides a vibration cylinder pressure sensor, which includes the above-mentioned vibration cylinder pressure sensor signal amplification circuit.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] The present invention discloses a signal amplifying circuit for a vibration cylinder pressure sensor. The filtering circuit filters signals in different frequency ranges to remove noise and stray signals in the vibration pickup signal, thereby ensuring the accuracy of the measurement result. The gain adjustment circuit can adjust the amplification factor of the signal according to actual needs to ensure that the signal is maintained at an appropriate level during subsequent processing. The signal generated by the limiting circuit is input to both ends of the exciting coil to make the vibration cylinder vibrate at the frequency of the signal.

[0020] The present invention discloses a signal amplifying circuit for a vibration cylinder pressure sensor, which has a simple circuit structure and is easy to realize. It uses an operational amplifier, a resistor, a capacitor and a diode for connection, is easy to implement and promote, and has the advantage of low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the working principle diagram of the existing vibration cylinder sensor;

[0022] Figure 2 This is a schematic diagram of a signal amplification circuit of a vibration cylinder pressure sensor of the present invention;

[0023] Figure 3 A circuit diagram of a filter circuit, a gain adjustment circuit, a phase adjustment circuit, and an amplitude limiting circuit in an embodiment of the present invention;

[0024] Figure 4 A circuit diagram of a temperature detection circuit in an embodiment of the present invention

[0025] Figure 5 1 and 2 are input and output waveforms of the vibration cylinder pressure sensor signal amplification circuit in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0027] like Figure 2 He Ru Figure 3 As shown, the present invention provides a signal amplifying circuit for a vibration cylinder pressure sensor, including a filtering circuit, a gain adjustment circuit, a phase adjustment circuit, a limiting circuit, a frequency detection circuit and a temperature detection circuit; the filtering circuit is used to amplify the vibration pickup signal V output by the vibration cylinder pressure sensor. IN After filtering, the signal after filtering is a sinusoidal signal V A , input to the input end of the gain adjustment circuit; the gain adjustment circuit is for the input sinusoidal signal VA Amplify the signal V B Input to the phase adjustment circuit and the frequency detection circuit; the phase adjustment circuit amplifies the gain signal V B Perform DC isolation processing to obtain a square wave signal V C And input to the limiting circuit, the limiting circuit is the square wave signal V C To limit the amplitude, the amplitude-limited square wave signal V D Input to the vibration tube, the vibration tube outputs the vibration pickup signal V IN Input to the filter circuit, the temperature detection circuit detects the temperature of the vibration tube and outputs the temperature detection signal V T The frequency detection circuit amplifies the signal V B Perform frequency detection and output square wave frequency signal V O .

[0028] like Figure 3 As shown, the filter circuit changes the upper cut-off frequency and the lower cut-off frequency by adjusting the values ​​of resistors R1 to R6, capacitors C1 to C3, and C10, thereby achieving signal filtering in different frequency ranges, removing noise and stray signals in the input signal, and improving the quality of the signal. The filter circuit includes resistors R1 to R6, capacitors C1 to C3, capacitor C10, and operational amplifier U1. In this embodiment, resistor R1 = 1.8 kΩ, resistor R2 = 1.5 kΩ, resistor R3 = 3 kΩ, resistor R4 = 3.9 kΩ, resistor R5 = 3.3 kΩ, resistor R6 = 75 kΩ, capacitor C1 = C10 = 4.7 nF, capacitor C2 = 10 nF, capacitor C3 = 2.2 nF, and operational amplifiers U1 to U4 and U6 are selected to have high common mode rejection ratio, high input impedance, and low noise, such as TL062 and TL082. One end of resistor R1 is connected to the pickup signal V IN The other end of the resistor R4 is connected to the resistor R5 and the capacitor C10, the other end of the capacitor C10 is connected to the ground, the other end of the resistor R5 is connected to the output of the operational amplifier U1, the non-inverting end of the operational amplifier U1 is connected to the ground, the other end of the resistor R4 is connected to the resistor R5 and the capacitor C10, the other end of the capacitor C10 is connected to the ground, and the other end of the resistor R5 is connected to the output of the operational amplifier U1.

[0029] The gain adjustment circuit's amplification factor is determined by the value of resistor R8 divided by the value of resistor R7, and the gain adjustment circuit outputs a gain amplified signal V B For the vibration pickup signal V INThe amplification factor is set according to the actual requirements of the circuit. In this embodiment, the resistor R7 = 1.5 kΩ, the resistor R8 = 75 kΩ, and the amplification process can be achieved by 50 times. The gain amplification signal V B On the one hand, the phase adjustment and amplitude limiting processing of the subsequent stage are carried out, and the feedback is fed back to the exciting coil, so that the vibration tube maintains vibration at the new natural frequency; on the other hand, the signal is processed by bandpass filtering to detect the signal frequency. One end of the resistor R7 is connected to the output end of the operational amplifier U1, and the other end is connected to the resistor R8 and the inverting end of the operational amplifier U2. The other end of the resistor R8 is connected to the output end of the operational amplifier U2.

[0030] In the phase adjustment circuit, due to the offset voltage of the operational amplifier U3, the gain amplification signal V output by the gain adjustment circuit B There is a DC offset voltage, so the phase adjustment circuit uses the operational amplifier U3 to compare the two input terminals and output a signal without DC offset voltage, specifically a square wave signal. The phase adjustment circuit isolates the DC offset voltage, and the DC offset voltage of the previous stage is V BIAS , then the resistance values ​​of R9 and R10 should satisfy V BIAS =V CC ×R10 / (R9+R10). In this embodiment, V CC The voltage range is 12V to 18V, preferably 15V, the resistor R9 = 82kΩ, the resistor R10 = 390Ω, the front-stage DC offset voltage is 70mV, and since the operational amplifier U3 is used in combination with multiple diodes, the signal output by the phase adjustment circuit is a square wave signal after diode shaping, the positive level is 3 times the diode voltage, and the negative level is 2 times the diode voltage. At the same time, the phase adjustment circuit causes a certain phase shift between the output square wave signal and the input gain amplified signal, so that the loop meets the phase condition of self-oscillation. The phase adjustment circuit includes resistors R9 to R12, capacitor C4, diodes D1 to D5 and operational amplifier U3.

[0031] One end of capacitor C4 is connected to the output end of operational amplifier U2, and the other end is connected to resistor R11. The other end of resistor R11 is connected to one end of resistor R12, the inverting end of operational amplifier U3, the cathode of diode D1, and the anode of diode D4. The non-inverting end of operational amplifier U3 is connected to resistor R9 and resistor R10. The other end of resistor R9 is connected to power supply V CC The other end of the resistor R10 is connected to the ground, the anode of the diode D1 is connected to the cathode of the diode D2, the anode of the diode D2 is connected to the cathode of the diode D3, the cathode of the diode D4 is connected to the anode of the diode D5 and is connected to the ground, and the anode of the diode D3 and the cathode of the diode D5 are connected to the output end of the operational amplifier U3.

[0032] The limiting circuit generates a constant amplitude limited square wave signal VD , input to both ends of the exciting coil, making the vibration cylinder vibrate at the frequency of the signal, limiting the square wave signal V D V CC With V DRIVE The signal between the two ends has a signal amplitude of (V CC -V Z1 )×R14 / (R14+R15), where V Z1 is the voltage regulation value of diode D6, V DRIVE is the excitation signal. The voltage amplitude of the collector of transistor Q1 in the limiting circuit is determined by the voltage regulation value of the voltage regulator. The voltage regulator is selected as 2CW60, and the voltage regulation value is about 12V. The input square wave signal is amplified to a square wave signal with an amplitude of 12V. Set the resistor R14 = 0.1kΩ, the resistor R15 = 2.2kΩ, and the voltage signal across R14 is fed back to the two ends of the excitation coil, so that the resonant cylinder vibrates at the frequency of the signal. Avoid problems such as damage to the sensitive structure of the sensor or failure to oscillate due to sudden changes in the power of the square wave signal. The limiting circuit includes resistors R13 to R16, capacitor C5, diode D6 and transistor Q1. One end of resistor R13 is connected to the output end of operational amplifier U3, and the other end is connected to the base of transistor Q1. The other end of resistor R12 is connected to the emitter of transistor Q1 and one end of resistor R16. The other end of resistor R16 is connected to ground. The collector of transistor Q1 is connected to one end of resistor R15, one end of capacitor C5 and the cathode of diode D6. The other end of capacitor C5 is connected to the anode of diode D6 and ground. The other end of resistor R15 is connected to one end of resistor R14. The other end of resistor R14 is connected to power supply V CC .

[0033] like Figure 4 As shown, the temperature detection circuit is connected to the vibration tube to detect the temperature of the vibration tube and output a temperature detection signal V T The temperature detection circuit includes resistors R24~R29, diodes D7~D8 and operational amplifier U6. The anode of diode D8 is connected to one end of resistor R29 and one end of resistor R24. The other end of resistor R24 ​​is connected to one end of resistor R25 and the in-phase end of operational amplifier U6. The other end of resistor R29 is connected to one end of resistor R28 and the cathode of diode D7. The other end of resistor R28 is connected to power supply V CC The anode of diode D7, the cathode of diode D8, and the other end of resistor R25 are connected to the ground, the inverting end of operational amplifier U6 is connected to one end of resistor R26 and one end of resistor R27, the other end of resistor R27 is connected to the ground, and the other end of resistor R26 is connected to the output end of operational amplifier U6.

[0034] The frequency detection circuit will input the vibration pickup signal V IN After filtering, it is converted into a square wave frequency signal V O , square wave frequency signal VO That is the resonant frequency of the vibration cylinder pressure sensor. The frequency detection circuit includes resistors R17-R23, capacitors C6-C9, operational amplifier U4 and comparator U5. The comparator U5 can select a general comparator, including LM111 and LM139. The inverting end of the operational amplifier U4, one end of the resistor R17, and one end of the capacitor C6 are connected to the output end of the operational amplifier U2, the other end of the resistor R17 is connected to one end of the resistor R18 and one end of the capacitor C7, the other end of the capacitor C7 is connected to the ground, the other end of the capacitor C6 and the other end of the resistor R8 are connected to the output end of the operational amplifier U4, the non-inverting end of the operational amplifier U4 is grounded, the output end of the operational amplifier U4 is connected to one end of the capacitor C8, the other end of the capacitor C8 is connected to one end of the resistor R19 and one end of the resistor R20, the other end of the resistor R20 is connected to the capacitor C9 and the inverting end of the comparator U5, the other end of the resistor R19 and the other end of the capacitor C9 are connected to the ground, the non-inverting end of the comparator U5 is connected to one end of the resistor R22 and the resistor R23, the other end of the resistor R23 is connected to the ground, the resistor R22 is connected to the output end of the comparator U5 and one end of the resistor R21, and the other end of the resistor R21 is connected to the power supply V CC In this embodiment, the resistor R17 = 3.3 kΩ, the resistor R18 = 10 kΩ, the resistor R19 = 6.8 kΩ, the resistor R20 = 15 kΩ, the resistor R21 = 6.8 kΩ, the resistor R22 = 3.3 kΩ, the capacitor C6 = C9 = 470 pF, C7 = 22 nF, and C8 = 2.2 nF.

[0035] The present invention provides a signal amplification circuit for a vibration cylinder pressure sensor, the input signal of which is a vibration pickup signal V with an amplitude of 5mV. IN , the frequency is 10kHz, the output signal is a square wave frequency signal V O , input and output waveforms are as follows Figure 5 shown.

[0036] In summary, the present invention provides a signal amplifying circuit for a vibration cylinder pressure sensor, including a filtering circuit, a gain adjustment circuit, a phase adjustment circuit, a limiting circuit, a frequency detection circuit and a temperature detection circuit. IN The sinusoidal signal V is obtained through the filtering circuit A , and then through the gain adjustment circuit, to achieve a certain gain amplitude adjustment, to obtain the gain amplification signal V B , respectively input to the phase adjustment circuit and the frequency detection circuit, the phase adjustment circuit outputs a square wave signal V C , input to the limiting circuit, the limiting circuit outputs a limited square wave signal V D , loaded on the vibrating cylinder, the gain adjustment circuit outputs the gain amplification signal V B After the frequency detection circuit, the square wave frequency signal V is output O, forming a closed-loop control system to realize the drive and detection of the resonant cylinder pressure sensor. The actual frequency of the vibrating cylinder body depends on the pressure felt.

[0037] In yet another embodiment of the present invention, a vibrating cylinder pressure sensor is provided, which can be used to implement the signal amplification circuit of the vibrating cylinder pressure sensor in the above embodiment.

[0038] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

Claims

1. A vibrating cylinder pressure sensor signal amplification circuit, characterized in that: It includes a filter circuit, a gain adjustment circuit, a phase adjustment circuit, a limiter circuit, a frequency detection circuit and a temperature detection circuit; The filter circuit is used to filter the vibration pickup signal V output by the vibration tube. IN After filtering, the signal after filtering is a sinusoidal signal V A , input to the gain adjustment circuit; The gain adjustment circuit is for the input sinusoidal signal V a Amplify the signal V B input to the phase adjustment circuit and the frequency detection circuit; The phase adjustment circuit amplifies the gain signal V B Perform DC isolation processing to obtain a square wave signal V C And input to the limiting circuit, the limiting circuit is C To limit the amplitude, the amplitude-limited square wave signal V D Input to the vibration tube, the vibration tube outputs the vibration pickup signal V IN The input is sent to the filter circuit, and the temperature detection circuit detects the temperature of the vibration tube and outputs the temperature detection signal V T ; The frequency detection circuit detects the amplified signal V B Perform frequency detection and output square wave frequency signal V O .

2. The vibrating cylinder pressure sensor signal amplifying circuit according to claim 1, characterized in that: The filter circuit includes resistors R1 to R6, capacitors C1 to C3, capacitor C10 and operational amplifier U1; One end of the resistor R1 is connected to the vibration pickup signal V IN The other end of the resistor R4 is connected to the resistor R5 and the capacitor C10, the other end of the capacitor C10 is connected to the ground, the other end of the resistor R5 is connected to the output of the operational amplifier U1, the non-inverting end of the operational amplifier U1 is connected to the ground, the other end of the resistor R4 is connected to the resistor R5 and the capacitor C10, the other end of the capacitor C10 is connected to the ground, and the other end of the resistor R5 is connected to the output of the operational amplifier U1.

3. The vibrating cylinder pressure sensor signal amplifying circuit according to claim 2, characterized in that: The gain adjustment circuit includes resistors R7-R8 and an operational amplifier U2; One end of the resistor R7 is connected to the output end of the operational amplifier U1, and the other end is connected to the resistor R8 and the inverting end of the operational amplifier U2. The other end of the resistor R8 is connected to the output end of the operational amplifier U2.

4. The vibrating cylinder pressure sensor signal amplifying circuit according to claim 3, characterized in that: The phase adjustment circuit includes resistors R9-R12, capacitor C4, diodes D1-D5 and operational amplifier U3; One end of the capacitor C4 is connected to the output end of the operational amplifier U2, and the other end is connected to the resistor R11. The other end of the resistor R11 is connected to one end of the resistor R12, the inverting end of the operational amplifier U3, the cathode of the diode D1, and the anode of the diode D4. The inverting end of the operational amplifier U3 is connected to the resistor R9 and the resistor R10. The other end of the resistor R9 is connected to the power supply V CC The other end of the resistor R10 is connected to the ground, the anode of the diode D1 is connected to the cathode of the diode D2, the anode of the diode D2 is connected to the cathode of the diode D3, the cathode of the diode D4 is connected to the anode of the diode D5 and is connected to the ground, and the anode of the diode D3 and the cathode of the diode D5 are connected to the output end of the operational amplifier U3.

5. The vibrating cylinder pressure sensor signal amplifying circuit according to claim 4, characterized in that: The amplitude limiting circuit includes resistors R13-R16, capacitor C5, diode D6 and transistor Q1; One end of the resistor R13 is connected to the output end of the operational amplifier U3, and the other end is connected to the base of the transistor Q1. The other end of the resistor R12 is connected to the emitter of the transistor Q1 and one end of the resistor R16. The other end of the resistor R16 is connected to the ground. The collector of the transistor Q1 is connected to one end of the resistor R15, one end of the capacitor C5, and the cathode of the diode D6. The other end of the capacitor C5 is connected to the ground with the anode of the diode D6. The other end of the resistor R15 is connected to one end of the resistor R14. The other end of the resistor R14 is connected to the power supply V CC .

6. The vibrating cylinder pressure sensor signal amplifying circuit according to claim 5, characterized in that: The frequency detection circuit includes resistors R17-R23, capacitors C6-C9, operational amplifier U4 and comparator U5; The inverting end of the operational amplifier U4, one end of the resistor R17, and one end of the capacitor C6 are connected to the output end of the operational amplifier U2, the other end of the resistor R17 is connected to one end of the resistor R18 and one end of the capacitor C7, the other end of the capacitor C7 is connected to the ground, the other end of the capacitor C6 and the other end of the resistor R8 are connected to the output end of the operational amplifier U4, the in-phase end of the operational amplifier U4 is grounded, the output end of the operational amplifier U4 is connected to one end of the capacitor C8, the other end of the capacitor C8 is connected to one end of the resistor R19 and one end of the resistor R20, the other end of the resistor R20 is connected to the capacitor C9 and the inverting end of the comparator U5, the other end of the resistor R19 is connected to the other end of the capacitor C9 is connected to the ground, the in-phase end of the comparator U5 is connected to one end of the resistor R22 and the resistor R23, the other end of the resistor R23 is connected to the ground, the resistor R22 is connected to the output end of the comparator U5 and one end of the resistor R21, and the other end of the resistor R21 is connected to the power supply V CC .

7. The vibrating cylinder pressure sensor signal amplifying circuit according to claim 6, characterized in that: The temperature detection circuit includes resistors R24-R29, diodes D7-D8 and an operational amplifier U6; The anode of the diode D8 is connected to one end of the resistor R29 and one end of the resistor R24. The other end of the resistor R24 ​​is connected to one end of the resistor R25 and the in-phase end of the operational amplifier U6. The other end of the resistor R29 is connected to one end of the resistor R28 and the cathode of the diode D7. The other end of the resistor R28 is connected to the power supply V CC The anode of diode D7, the cathode of diode D8, and the other end of resistor R25 are connected to the ground, the inverting end of operational amplifier U6 is connected to one end of resistor R26 and one end of resistor R27, the other end of resistor R27 is connected to the ground, and the other end of resistor R26 is connected to the output end of operational amplifier U6.

8. The vibrating cylinder pressure sensor signal amplifying circuit according to claim 1, characterized in that: The gain factor of the gain adjustment circuit is determined by the value of resistor R8 divided by the value of resistor R7.

9. The signal amplifying circuit of the vibrating cylinder pressure sensor according to claim 7, characterized in that: The comparator U5 includes LM111 and LM139; the operational amplifiers U1-U4 and U6 include TL062 and TL082.

10. A vibrating cylinder pressure sensor, characterized in that: A vibration tube pressure sensor signal amplification circuit as described in any one of claims 1 to 9 is installed.

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