Liquid floated gyro signal conversion circuit, conversion device and conditioning conversion method

Abstract

The application provides a liquid floated gyro signal conversion circuit, a conversion device and a conditioning conversion method, the conversion circuit comprises a differential amplification circuit, a phase-sensitive demodulation circuit, a direct current amplification filter circuit, an alternating current output circuit, an anti-reverse connection filter circuit and a secondary power supply circuit, the phase-sensitive demodulation circuit and the direct current amplification filter circuit are used for phase demodulation and conditioning processing of a gyro output signal, a direct current output signal with small scale factor discreteness for measuring a signal acquisition device is output, meanwhile, the gyro output signal is independently subjected to voltage following processing, and an alternating current output signal is output; and the alternating current and the direct current signal are parallel output and do not affect each other, the signal output quality is improved while the gyro body output signal is truly restored, and the test efficiency of applying the liquid floated gyro to measure the angular velocity of a carrier rotating along a gyro sensitive axis is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of inertial sensors, and particularly relates to a liquid floated gyro signal conversion circuit, a conversion device and a conditioning conversion method. BACKGROUND

[0002] The liquid floated gyro can measure the angular rate of the carrier along the gyro sensitive axis direction and convert the angular rate into an alternating voltage signal proportional to the angular rate, and has a self-checking function. In the process of development, acceptance and use of the liquid floated gyro, the alternating signal output by the gyro body is weak and susceptible to external interference, and the power, amplitude and AC / DC characteristics of the signal often do not meet the use requirements. Therefore, the alternating signal output by the gyro body needs to be processed to make the signal have the characteristics of high precision, low distortion and anti-interference.

[0003] The traditional method for measuring the alternating signal output by the liquid floated gyro body is to directly measure the signal at the signal output end of the liquid floated gyro by using a test device. This method introduces external interference signals, and due to the phase difference between the gyro body signal and the excitation signal, the demodulation efficiency is reduced, which causes the scale factor of the interference demodulated direct current signal to be discrete due to the different phase differences, and the conventional signal conversion circuit cannot solve this problem. SUMMARY

[0004] The present application aims to solve the problems that the existing liquid floated gyro output signal measurement method introduces interference and the scale factor of the interference demodulated direct current output signal is discrete, and provides a liquid floated gyro signal conversion circuit, a conversion device and a conversion conditioning method. The gyro output signal is processed by a differential amplification circuit, a phase-sensitive demodulation circuit, a direct current amplification and filtering circuit, an alternating current output circuit, an anti-reverse connection filtering circuit and a secondary power supply circuit. The quality of the output signal can truly restore the gyro body output signal, the circuit has strong anti-interference ability, and the alternating current and direct current signals are output in parallel and do not affect each other, which greatly improves the test efficiency.

[0005] To achieve the above-mentioned purpose, the technical solution provided by the present application is as follows:

[0006] A liquid floated gyro signal conversion circuit, comprising a differential amplification circuit, a phase-sensitive demodulation circuit, a direct current amplification and filtering circuit, an alternating current output circuit, an anti-reverse connection filtering circuit and a secondary power supply circuit;

[0007] The differential amplification circuit is used to convert the gyro differential signal output by the liquid floated gyro into a single-ended signal with GND as a reference;

[0008] The phase-sensitive demodulation circuit is used to phase demodulate the single-ended signal converted to have GND as a reference, so that the positive and negative half-wave signals in the single-ended signal are completely demodulated, and is used to convert the phase demodulated signal into a direct current signal.

[0009] The direct current amplification filter circuit is used for amplifying and isolating the direct current signal output by the phase-sensitive demodulation circuit, and converting the direct current signal into a direct current output signal matched with the polarity of the liquid floated gyroscope; the direct current output signal is used for measurement by an external test device;

[0010] The alternating current output circuit is used for voltage following processing of the converted single-ended signal with GND as the reference, to obtain an alternating current output signal for measurement by an external test device;

[0011] The anti-reverse connection filter circuit is used for supplying the power supply signal of an external power supply to the differential amplification circuit, the phase-sensitive demodulation circuit, the direct current amplification filter circuit, the alternating current output circuit and the secondary power supply circuit after the power supply signal is conditioned, and can prevent circuit damage caused by positive and negative reverse connection of the power supply.

[0012] The differential amplification circuit comprises a resistor R6, a capacitor C6, a capacitor C21 and an operational amplifier N2, the noninverting input terminal and the inverting input terminal of the operational amplifier N2 are respectively connected to the wiring port J2 and the wiring port J4; one end of the capacitor C6 is connected to the positive power supply port of the operational amplifier N2, and the other end is connected to the ground; one end of the capacitor C21 is connected to the negative power supply port of the operational amplifier N2, and the other end is connected to the ground; the resistor R6 is connected to the two gain adjustment ports on the same side of the operational amplifier N2; the reference terminal of the operational amplifier N2 is connected to the ground; the resistor R6 is used for adjusting the circuit gain, and the operational amplifier N2 is used for converting the differential signal output by the liquid floated gyroscope into a single-ended signal with GND as the reference.

[0013] The phase-sensitive demodulation circuit comprises a full-wave phase-sensitive demodulation circuit and a demodulation reference circuit, and the full-wave phase-sensitive demodulation circuit comprises an inverting proportional amplification circuit and a switching circuit.

[0014] The demodulation reference circuit is used for converting the excitation signal generated by the external excitation circuit into a reference signal.

[0015] The inverting proportional amplification circuit is used for inversely amplifying the single-ended signal with GND as the reference output by the differential amplification circuit.

[0016] The switching circuit is used for being turned on or turned off under the control of the reference signal, to convert the positive half wave or the negative half wave of the amplified single-ended signal with GND as the reference into a positive or negative direct current signal.

[0017] The demodulation reference circuit comprises resistors R1, R3, R4, a potentiometer RP1, a capacitor C1, an operational amplifier U3C, diodes D1 and D2; the resistors R1 and the potentiometer RP1 are connected in parallel, one end of which is connected to a wire port J1, and the other end is connected to the inverting input terminal of the operational amplifier U3C and one end of the capacitor C1, and the other end of the capacitor C1 is connected to the non-inverting input terminal of the operational amplifier U3C and the ground wire GND; the output terminal of the operational amplifier U3C is connected to the diode D2 and the resistor R3 in series; the diode D1 and the resistor R4 are connected in parallel, the positive electrode of the diode D1 is connected to the ground, the negative electrode is connected between the resistor R3 and the resistor R4, and is connected to the input terminal of the switch circuit; the wire port J1 is connected to an external excitation circuit, and the resistance values of the resistors R1 and the potentiometer RP1 can be adjusted to control the phase of the demodulation reference signal relative to the differential signal of the gyroscope;

[0018] The inverting proportional amplification circuit comprises resistors R7, R5, an operational amplifier U3A, a capacitor C18 and a capacitor C20; the input terminal of the resistor R7 is connected to the output terminal of the differential amplification circuit, and the output terminal is connected to the inverting input terminal of the operational amplifier U3A; the resistors R5 are connected to the output terminal and the inverting input terminal of the operational amplifier U3A respectively; one end of the capacitors C18 and C20 is connected to the ground wire GND respectively, and the other end is connected to the positive power supply terminal and the negative power supply terminal of the operational amplifier U3A respectively; the resistors R7 and R5 are used for adjusting the gain of the circuit, and the operational amplifier U3A is used for inversely amplifying the single-ended signal with GND as the reference output by the differential amplification circuit;

[0019] The switch circuit comprises an analog switch S1, capacitors C4, C5 and C22; the analog signal positive power supply input terminal VS+ and the analog signal negative power supply input terminal VS- of the analog switch S1 are connected to the ground wire GND through the capacitors C4 and C22 respectively; the normally closed terminal, the normally open terminal and the logic level input terminal are connected to the output terminal of the reverse proportional circuit, the output terminal of the differential amplification circuit and the negative electrode of the diode D1 in the demodulation reference circuit respectively; the ground terminal of the analog switch S1 is connected to the ground wire, the logic level positive power supply input terminal is connected to the ground wire through the capacitor C5, and the output terminal of the analog switch S1 is connected to the input terminal of the direct current amplification and filtering circuit;

[0020] The analog signal positive power supply input terminal VS+ of the analog switch S1 is also connected to the input terminal of the secondary power supply circuit, the analog signal negative power supply input terminal VS- is also connected to the negative power supply output terminal of the anti-reverse connection filtering circuit, and the logic level positive power supply input terminal is also connected to the output terminal of the secondary power supply circuit.

[0021] Further, the secondary power supply circuit is used to supply power to the analog switch S1 in the switch circuit alone; the secondary power supply circuit comprises a capacitor C3, a capacitor C2 and a voltage stabilizer U2; one end of the capacitor C2 and the capacitor C3 is connected to the ground wire GND respectively, and the other end is connected to the input end Vi and the output end Vo of the voltage stabilizer U2 respectively, the input end Vi is also connected to the analog signal positive power supply input end VS+ of the analog switch S1, and the output end Vo is also connected to the logic level positive power supply input end of the analog switch S1; the ground end of the voltage stabilizer U2 is connected to the ground wire GND.

[0022] Further, the direct current amplification filter circuit comprises a resistor R2, a resistor R9, a resistor R10, a resistor R12, a resistor R13, a capacitor C25, a capacitor C19 and an operational amplifier U3D; one end of the resistor R9 is connected to the output end of the switch circuit, and the other end is connected to the non-inverting input end of the operational amplifier U3D after being connected with the resistor R10 in series; the resistor R2, the resistor R12 and the resistor R13 are connected in series in sequence and then connected to the ground wire GND, and the inverting input end of the operational amplifier U3D is connected between the resistor R12 and the resistor R13; one end of the capacitor C25 is connected between the resistor R9 and the resistor R10, and the other end is connected to the input end of the resistor R2; one end of the capacitor C19 is connected between the resistor R10 and the operational amplifier U3D, and the resistor R13 is used to adjust the gain of the circuit;

[0023] The resistor R9, the resistor R10, the capacitor C19, the capacitor C25 and the operational amplifier U3D constitute a non-inverting amplification low-pass filter, so that the polarity of the direct current signal output by the phase-sensitive demodulation circuit is consistent with the rotation polarity of the liquid floating gyroscope.

[0024] Further, the anti-reverse connection filter circuit comprises a capacitor C23, a capacitor C24, a diode D3 and a diode D4; the capacitor C23 and the capacitor C24 are connected in series, and the positive electrode of the capacitor C24 is connected to the negative electrode of the capacitor C23; the connection line of the capacitor C23 and the capacitor C24 outputs two paths, one of which is connected to the ground, and the other of which is connected to the wiring port J7 provided; the wiring port J7 is used to connect the power supply ground of the external power supply;

[0025] The negative electrode of the diode D3 is connected to the positive electrode of the capacitor C23 and then connected to the input end Vi of the voltage stabilizer U2 in the secondary power supply circuit, the positive power supply port of the operational amplifier N2 in the differential amplification circuit, the positive power supply port of the operational amplifier U3A in the phase-sensitive demodulation circuit, the positive power supply port of the direct current amplification filter circuit and the positive power supply port of the alternating current output circuit; the positive electrode of the diode D3 is connected to the wiring port J5 provided, and the wiring port J5 is used to connect the positive electrode of the external power supply;

[0026] The positive electrode of the diode D4 is connected with the negative electrode of the capacitor C24, and then connected with the negative power supply port of the operational amplifier N2 in the differential amplification circuit, the negative power supply port of the operational amplifier U3A in the phase-sensitive demodulation circuit, the analog signal negative power supply input end VS- of the analog switch S1, the negative power supply port of the direct current amplification filter circuit, and the negative power supply port of the alternating current output circuit; the negative electrode of the diode D4 is connected with the wiring port J6, and the wiring port J6 is used for connecting with the negative electrode of the external power supply.

[0027] Further, the alternating current output circuit comprises a voltage follower U3B; the non-inverting input end of the voltage follower U3B is connected with the output end of the differential amplification circuit, the output end of the voltage follower U3B is connected with the inverting input end of the voltage follower U3B, so as to convert the output signal of the differential amplification circuit into an alternating current output signal; the output end of the voltage follower U3B is also connected with the wiring port J6, and the wiring port J6 is connected with the signal input end of the external test equipment.

[0028] Based on the above-mentioned liquid floated gyro signal conversion circuit, a method for processing and converting the output signal of the liquid floated gyro comprises the following steps:

[0029] Step 1: amplifying and converting the gyro differential signal output by the liquid floated gyro, and outputting a single-ended signal with GND as a reference;

[0030] Step 2: phase demodulating the single-ended signal with GND as a reference, so that the positive and negative half-wave signals in the single-ended signal are completely output and converted into a direct current signal;

[0031] Meanwhile, the single-ended signal with GND as a reference is subjected to voltage follower processing, so as to obtain an alternating current output signal for measurement by an external test equipment;

[0032] Step 3: amplifying and filtering the direct current signal output by the phase demodulation in step 2, so as to obtain a direct current output signal for measurement by an external test equipment.

[0033] A liquid floated gyro signal conversion device comprises an electrical connector XP1 and a printed board; the liquid floated gyro signal conversion circuit is fixed on the printed board;

[0034] The electrical connector XP1 has a plurality of power supply interfaces and signal interfaces; one end of the power supply interfaces and the signal interfaces is respectively connected with the corresponding wiring ports in the liquid floated gyro signal conversion circuit; the other end of the power supply interfaces and the signal interfaces is used for connecting with an external power supply, a liquid floated gyro output end and a test equipment.

[0035] The advantages of the present application are:

[0036] The liquid floated gyro signal conversion circuit comprises a differential amplification circuit, a phase-sensitive demodulation circuit, a direct current amplification filter circuit, an alternating current output circuit, an anti-reverse connection filter circuit and a secondary power supply circuit. Through multi-stage processing of the gyro output signal, the alternating current signal output by the gyro body is converted and output as alternating current and direct current signals, and the alternating current and direct current signals are output in parallel and do not affect each other. The direct current output signal has small scale factor discreteness, the gyro body output signal is truly restored, the signal output quality is improved, and the test efficiency of the application of the liquid floated gyro in measuring the angular velocity of a carrier rotating along the sensitive axis of the gyro is greatly improved. Specific points include:

[0037] 1. The differential amplification circuit in the application amplifies the gyro body output signal, effectively isolates the reverse interference of the subsequent conversion circuit on the weak signal of the gyro body, effectively suppresses the common mode interference of the gyro body on the conversion circuit, adjusts the polarity of the direct current output signal by adjusting the differential input, effectively isolates the interference between the liquid floated gyro and the conversion circuit board of the application, and adjusts the polarity of the direct current output signal.

[0038] 2. The voltage follower is used in the alternating current output circuit in the application, which effectively isolates the input and output ends of the alternating current output circuit, avoids mutual interference, and ensures the purity of the demodulation input signal.

[0039] 3. The phase-sensitive demodulation circuit in the application uses full-wave phase-sensitive demodulation, which can adjust the demodulation efficiency to the optimum according to the phase of the gyro body output signal, significantly reduces the direct current output scale factor discreteness caused by the phase difference between the liquid floated gyro body signal and the excitation signal, ensures that the positive and negative half-wave signals of the gyro are completely demodulated, eliminates the demodulation spike, and improves the signal output quality.

[0040] 4. The direct current amplification filter circuit in the application uses a same-phase low-pass amplification filter, which effectively suppresses the interference between the front and rear ends of the circuit, and ensures that the polarity of the self-checking output signal is consistent with the polarity of the rotating output signal. It should be noted that the self-checking output signal refers to the input of a specified size of current on the gyro torque converter to realize the self-calibration and self-detection function of the sensor, and the gyro outputs a fixed size of output signal. The rotating output signal refers to the signal output by the gyro when it rotates along its sensitive axis. According to the technical requirements of the gyro, the polarities of the two kinds of output signals must be consistent.

[0041] 5. The anti-reverse connection filter circuit in the application uses a diode protection, which ensures that the circuit will not be damaged when the positive and negative power supplies are connected in reverse, and can also suppress the positive and negative power supply ripple, making the positive and negative power supplies more pure.

[0042] In addition, the conversion circuit in the application uses common discrete components, the components are self-controllable, and the types and number of components are optimized to the minimum, achieving the best cost-effectiveness, and the implementation cost is greatly reduced compared with the traditional technology.

[0043] The signal conversion circuit can be adapted to the output signal conversion of various types of liquid floated gyro bodies, has wide application range and high practicability.

[0044] Additional aspects and advantages of the present application will be described in the following description, will become apparent from the following description, or will be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is a composition block diagram of the signal conversion circuit of the liquid floated gyro of the present application;

[0046] Figure 2 is a circuit connection diagram of the differential amplification circuit, the phase-sensitive demodulation circuit, the direct current amplification filter circuit and the alternating current output circuit in the signal conversion circuit of the liquid floated gyro of the present application;

[0047] Figure 3 is a circuit diagram of the anti-reverse connection filter circuit in the signal conversion circuit of the liquid floated gyro of the present application;

[0048] Figure 4 is a circuit diagram of the secondary power supply circuit in the signal conversion circuit of the liquid floated gyro of the present application;

[0049] Figure 5 is a schematic diagram of the signal conversion device of the liquid floated gyro of the present application. DETAILED DESCRIPTION

[0050] The embodiments of the present application are described in detail below, which are exemplary and are intended to explain the present application, and cannot be understood as the limitation of the present application.

[0051] Reference Figures 1-2 The embodiment of the present application provides a signal conversion circuit of a liquid floated gyro, which comprises a differential amplification circuit, a phase-sensitive demodulation circuit, a direct current amplification filter circuit, an alternating current output circuit, an anti-reverse connection filter circuit and a secondary power supply circuit.

[0052] The differential amplification circuit is used for converting the gyro differential signal output by the liquid floated gyro body into a single-ended signal with GND as reference. The differential amplification circuit comprises resistance R6, capacitance C6, capacitance C21 and operational amplifier N2, the non-inverting input terminal of the operational amplifier N2 is connected with the wire terminal port J2, the inverting input terminal is connected with the wire terminal port J4, the wire terminal port J2 and the wire terminal port J4 are respectively connected with two output terminals of the liquid floated gyro; one end of the capacitance C6 is connected with the positive power terminal of the operational amplifier N2, and the other end is connected with the ground; one end of the capacitance C21 is connected with the negative power terminal of the operational amplifier N2, and the other end is connected with the ground; the reference terminal 1 of the operational amplifier N2 is connected with the ground; the resistance R6 is connected between the gain adjustment terminal 2 and the gain adjustment terminal 3 on the same side of the operational amplifier N2; the resistance R6 plays a role of adjusting the gain of the circuit, the capacitance C6 and the capacitance C21 play a role of filtering, and the operational amplifier N2 plays a role of converting the signal.

[0053] The phase-sensitive demodulation circuit is used for demodulating the single-ended signal with GND as reference output by the differential amplification circuit into a direct current signal. The phase-sensitive demodulation circuit has full-wave phase-sensitive demodulation and demodulation reference signal phase adjustment functions. The phase-sensitive demodulation circuit comprises a full-wave phase-sensitive demodulation circuit and a demodulation reference circuit. The full-wave phase-sensitive demodulation circuit is composed of an inverting proportional amplification circuit and a switch circuit.

[0054] The inverting proportional amplification circuit comprises resistance R7, resistance R5, operational amplifier U3A, capacitance C18 and capacitance C20. One end of the resistance R7 is connected with the output terminal of the differential amplification circuit, and the other end is connected with the inverting input terminal of the operational amplifier U3A; one end of the resistance R5 is connected with the inverting input terminal of the operational amplifier U3A, and the other end is connected with the output terminal of the operational amplifier U3A; the non-inverting input terminal of the operational amplifier U3A is connected with the GND; one end of the capacitance C18 and the capacitance C20 is respectively connected with the positive power terminal and the negative power terminal of the operational amplifier U3A, and the other end of the capacitance C18 and the capacitance C20 is respectively connected with the GND; the resistance R7 and the resistance R5 play a role of adjusting the gain, and the operational amplifier U3A plays a role of inverting amplification. The output terminal of the inverting proportional amplification circuit is connected with the input terminal of the switch circuit.

[0055] The switch circuit is composed of analog switch S1, capacitor C4, capacitor C5 and capacitor C22. The output terminal of operational amplifier U3A in the inverting proportional amplification circuit is connected with the normally closed terminal 1 of analog switch S1, and the normally open terminal 2 of analog switch S1 is connected with the output terminal of operational amplifier N2. One end of capacitor C4 and capacitor C22 is connected with ground wire GND respectively, and the other end is connected with analog signal positive power input terminal VS+ and analog signal negative power input terminal VS- of analog switch S1 respectively; one end of capacitor C5 is connected with ground wire GND, and the other end is connected with logic level positive power input terminal 4 of analog switch S1; the output terminal of analog switch S1 is connected with ground wire GND, and the logic level input terminal 3 of analog switch S1 is connected with the cathode of diode D1 in the demodulation reference circuit, and the output terminal of analog switch S1 is connected with one end of resistor R9 in the direct current amplification filter circuit. The analog switch S1 is used to be turned on or turned off under the control of the reference signal outputted by the demodulation reference circuit, and the positive half wave and negative half wave of the single-ended signal amplified by the inverting proportional amplification circuit are converted into direct current signals with positive and negative polarities respectively. The specific working process is as follows: when the phase difference between the input signal of the full-wave phase-sensitive demodulation circuit and the reference signal outputted by the demodulation reference circuit is 0°, the positive half wave signal in the input signal of the full-wave phase-sensitive demodulation circuit is converted into negative half wave signal by the inverting proportional amplification circuit, and is transmitted to the output terminal by the normally closed terminal 1 of analog switch S1, and the negative half wave signal is transmitted to the output terminal by the normally open terminal 2 of analog switch S1, so that two continuous negative half waves are obtained at the output terminal of analog switch S1 in one sine wave period; when the phase difference between the input signal of the full-wave phase-sensitive demodulation circuit and the reference signal outputted by the demodulation reference circuit is 180°, the positive half wave signal is transmitted to the output terminal by the normally open terminal 2 of analog switch S1, and the negative half wave signal is converted into positive half wave signal by the inverting proportional amplification circuit and is transmitted to the output terminal by the normally closed terminal 1 of analog switch S1, so that two continuous positive half waves are obtained at the output terminal of analog switch S1 in one sine wave period. Capacitors C4, C5 and C22 have the function of filtering.

[0056] The demodulation reference circuit is composed of RC circuit, comparator and rectifier circuit. The terminal port J1 is connected with excitation signal, one end of the resistor R1 is connected with the terminal J1, the other end is connected with the inverting input terminal of the operational amplifier U3C, one end of the potentiometer RP1 is connected with the terminal J1, the other end and the adjusting end are both connected with the inverting input terminal of the operational amplifier U3C; the capacitor C1 is connected with the non-inverting input terminal and the inverting input terminal of the operational amplifier U3C respectively; the non-inverting input terminal of the operational amplifier U3C is connected with the ground wire GND. The anode of the diode D2 is connected with the output terminal of the operational amplifier U3C, the cathode is connected with one end of the resistor R3, the other end of the resistor R3 is connected with the cathode of the diode D1 and one end of the resistor R4 respectively; the anode of the diode D1 and the other end of the resistor R4 are connected with the ground wire GND. The resistor R1, the potentiometer RP1 and the capacitor C1 constitute the RC circuit, which plays a role of phase adjustment, adjusting the resistor R1 and the potentiometer RP1 can control the phase of the demodulation reference signal relative to the gyro signal, the diode D2 plays a role of rectification, the diode D1 plays a role of signal shaping, and the resistor R3 and the resistor R4 play a role of voltage division.

[0057] The direct current amplification filter circuit is used for converting the direct current signal outputted by the phase sensitive demodulation circuit into direct current output signal. The direct current amplification filter includes the resistor R2, the resistor R9, the resistor R10, the resistor R12, the resistor R13, the capacitor C25, the capacitor C19 and the operational amplifier U3D. The resistor R9 and the resistor R10 are connected in series, the input end of the resistor R9 is connected with the output end 1 of the analog switch in the phase sensitive demodulation circuit; the resistor R2, the resistor R12 and the resistor R13 are connected in series, and the inverting input terminal of the operational amplifier U3D is connected between the resistor R12 and the resistor R13; one end of the capacitor C25 is connected between the resistor R9 and the resistor R10, and the other end is connected with the input end of the resistor R2; one end of the capacitor C19 is connected between the resistor R10 and the non-inverting input terminal of the operational amplifier U3D, and the other end is connected with the ground wire GND; the non-inverting input terminal of the operational amplifier U3D is connected with the output end of the resistor R10, and the inverting input terminal of the operational amplifier U3D is connected between the resistor R12 and the resistor R13; the output terminal of the operational amplifier U3D is connected with the terminal port J3, and the terminal port J3 is connected with the signal input end of the test equipment. The resistor R2, the resistor R12 and the resistor R13 play a role of adjusting gain, the resistor R9, the resistor R10, the capacitor C19 and the capacitor C25 play a role of filtering, and the operational amplifier U3D plays a role of amplification. The direct current amplification filter circuit adopts the non-inverting amplification low-pass filter, which ensures that the polarity of the self-checking output signal is consistent with the polarity of the liquid floating gyro rotation output signal, saves the number of components, and also has the functions of amplification and interference isolation.

[0058] The AC output circuit is used for converting the single-ended signal referenced to GND output by the differential amplifier circuit into a measurable AC output signal. The AC output circuit comprises a voltage follower U3B, the non-inverting input terminal of the voltage follower U3B is connected to the output terminal of the operational amplifier N2 in the differential amplifier circuit, and the output terminal of the voltage follower U3B is connected to the inverting input terminal of the voltage follower U3B, so as to convert the output signal of the differential amplifier circuit into a measurable AC output signal while having the interference isolation function. The output terminal of the AC output circuit is connected to the connection port J6, and the connection port J6 is connected to the signal input terminal of the external test equipment. The voltage follower U3B has the signal transmission and interference isolation functions.

[0059] With reference to Figure 3 The reverse connection prevention filter circuit is used for supplying power to the differential amplifier circuit, the phase-sensitive demodulation circuit, the DC amplification filter circuit, the AC output circuit and the secondary power supply circuit, and can prevent the positive and negative power supply from being reversely connected, so as to avoid damaging the circuit when the positive and negative poles of the power supply are reversely connected, and can suppress the positive and negative power supply ripple, so that the positive and negative power supply is more pure.

[0060] The reverse connection prevention filter circuit comprises a capacitor C23, a capacitor C24, a diode D3 and a diode D4. The capacitor C23 and the capacitor C24 are connected in series, and the positive pole of the capacitor C24 is connected to the negative pole of the capacitor C23. The capacitor C23 and the capacitor C24 are connected to output two paths, one of which is connected to the ground, and the other of which is connected to the connection port J7. The connection port J7 is used for connecting the power supply ground of the external power supply, and is used as a reference reference for a single-ended signal. The positive pole of the diode D3 is connected to the connection port J5, and the connection port J5 is used for connecting the positive pole of the external power supply. The negative pole of the diode D3 is connected to the positive pole of the capacitor C23, and outputs a positive voltage VP. The positive voltage VP is connected to the input terminal of the voltage stabilizer U2 in the secondary power supply circuit, the positive power supply terminal of the operational amplifier N2 in the differential amplifier circuit, the positive power supply terminal of the operational amplifier U3A in the phase-sensitive demodulation circuit, and the positive power supply terminals of the DC amplification filter circuit and the AC output circuit. The negative pole of the diode D4 is connected to the connection port J8, and the connection port J8 is used for connecting the negative pole of the external power supply to receive negative power supply. The positive pole of the diode D4 is connected to the negative pole of the capacitor C24, and outputs a negative voltage VN. The negative voltage VN is connected to the negative power supply terminal of the operational amplifier N2 in the differential amplifier circuit, the negative power supply terminal of the operational amplifier U3A in the phase-sensitive demodulation circuit, the negative power supply input terminal VS- of the analog switch, the negative power supply terminal of the DC amplification filter circuit and the negative power supply terminal of the AC output circuit. The diode D3 and the diode D4 have the one-way isolation function, and the capacitor C23 and the capacitor C24 have the filtering function.

[0061] With reference to Figure 4The secondary power supply circuit is used for providing working voltage for the analog switch S1 in the switch circuit. The secondary power supply circuit comprises a capacitor C3, a capacitor C2 and a voltage stabilizer U2. One end of the capacitor C2 and the capacitor C3 is connected with the ground wire GND respectively, and the other end is connected with the input end Vi and the output end Vo of the voltage stabilizer U2 respectively, the input end Vi is also connected with the analog signal positive power input end VS+ of the analog switch S1, and the output end Vo is also connected with the logic level positive power input end 4 of the analog switch S1. The ground end of the voltage stabilizer U2 is connected with the ground wire GND. The voltage stabilizer U2 plays a role of voltage conversion.

[0062] With reference to Figure 5 The liquid floated gyro signal conversion circuit is fixed on the printed board, and forms a liquid floated gyro signal conversion circuit board through the external electric connector XP1. The electric connector XP1 has multiple interfaces, one end of the interface is connected with the connection port J1-J8 in the conversion circuit respectively, and the other end of the interface is connected with the external power supply, the liquid floated gyroscope output end and the external test equipment. Specifically, each component in the circuit is fixed on the printed board by welding.

[0063] The process of using the conversion circuit to regulate and convert the liquid floated gyro signal is as follows:

[0064] Step 1, the liquid floated gyro outputs the gyro differential signal and transmits it to the differential amplification circuit; the differential amplification circuit amplifies and converts the received gyro differential signal, and outputs the single-ended signal with GND as the reference as the input signal of the phase-sensitive demodulation circuit and the alternating current output circuit.

[0065] Step 2, the phase-sensitive demodulation circuit demodulates the single-ended signal with GND as the reference output by step 1, so that the positive and negative half-wave signals in the single-ended signal are completely output and converted into direct current signals.

[0066] The principle of phase-sensitive demodulation circuit for phase demodulation of the output single-ended signal is: full-wave phase-sensitive demodulation is to convert the input single-ended signal into a direct current signal proportional to it. When the phase difference between the input signal of the full-wave phase-sensitive demodulation circuit and the demodulation reference signal is 0°, the positive half-wave signal is converted into a negative half-wave signal by the inverting proportional amplification circuit and is transmitted to the output end of the normally closed end 1 of the analog switch S1, and the negative half-wave signal is transmitted to the output end of the normally open end 2 of the analog switch S1. In a sine wave period, two consecutive negative half-waves are obtained at the output end of the analog switch S1. When the phase difference between the input signal of the full-wave phase-sensitive demodulation circuit and the demodulation reference signal is 180°, the positive half-wave signal is transmitted to the output end of the normally open end 2 of the analog switch S1, and the negative half-wave signal is converted into a positive half-wave signal by the inverting amplification circuit and is transmitted to the output end of the normally closed end 1 of the analog switch S1. Thus, in a sine wave period, two consecutive positive half-waves are obtained at the output end of the analog switch S1. When the phase difference between the input signal of the full-wave phase-sensitive demodulation circuit and the demodulation reference signal is neither 0° nor 180°, in a sine wave period, the signal obtained at the output end of the analog switch S1 is not the two standard consecutive positive half-waves or negative half-waves described above, and the waveform of the output signal will be distorted. In view of this phenomenon, an RC circuit (composed of a resistor R1, a potentiometer RP1 and a capacitor C1) is added to the demodulation reference circuit, and the phase difference between the reference signal and the input signal of the full-wave phase-sensitive demodulation circuit is changed by adjusting the RC circuit, so as to ensure that the demodulation output signal does not distort. The RC circuit plays a role in adjusting the phase, and the low pass makes the phase of the output signal lag behind the phase of the input signal, and the high pass makes the phase of the output signal lead the phase of the input signal. In the embodiment, the low pass connection method is adopted, and the positions of the resistor and the capacitor are exchanged, that is, the high pass connection method. In the specific operation, the time constant of the RC circuit can be adjusted while observing whether the output waveform is distorted until the demodulation output waveform is normal.

[0067] At the same time, the AC output circuit separately processes the single-ended signal with GND as the reference output by step 1 for voltage following, and obtains an AC output signal for measurement by an external test device.

[0068] Step 3: The DC amplification and filtering circuit amplifies and filters the DC signal output after step 2 phase demodulation, and obtains a DC output signal with low scale factor discreteness as a measurement signal of an external test device.

[0069] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any skilled person in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A signal conversion circuit for a liquid floated gyroscope, characterized by The differential amplification circuit, the phase-sensitive demodulation circuit, the direct current amplification filter circuit, the alternating current output circuit, the reverse connection prevention filter circuit and the secondary power supply circuit are included. The differential amplification circuit is used for converting the gyro differential signal output by the liquid floated gyroscope into a single-ended signal with GND as a reference. The phase-sensitive demodulation circuit is used for phase demodulating the single-ended signal with GND as a reference, so that the positive and negative half-wave signals in the single-ended signal are completely demodulated, and is used for converting the phase-demodulated signal into a direct current signal. The direct current amplification filter circuit is used for amplifying and isolating the direct current signal output by the phase-sensitive demodulation circuit, and converting the direct current signal into a direct current output signal matched with the polarity of the liquid floated gyroscope; and the direct current output signal is used for measurement by an external test device. The alternating current output circuit is used for voltage following processing of the single-ended signal with GND as a reference, so as to obtain an alternating current output signal for measurement by an external test device. The reverse connection prevention filter circuit is used for conditioning the power supply signal of an external power supply, and supplying the power supply signal to the differential amplification circuit, the phase-sensitive demodulation circuit, the direct current amplification filter circuit, the alternating current output circuit and the secondary power supply circuit, and preventing damage of the circuit caused by reverse connection of the positive and negative poles of the power supply. The differential amplification circuit includes a resistor R6, a capacitor C6, a capacitor C21 and an operational amplifier N2, the noninverting input terminal and the inverting input terminal of the operational amplifier N2 are connected to the wiring port J2 and the wiring port J4 respectively, one end of the capacitor C6 is connected to the positive power supply port of the operational amplifier N2, and the other end is connected to the ground; one end of the capacitor C21 is connected to the negative power supply port of the operational amplifier N2, and the other end is connected to the ground; the resistor R6 is connected to the two gain adjustment ports on the same side of the operational amplifier N2; and the reference terminal of the operational amplifier N2 is connected to the ground; the resistor R6 is used for adjusting the circuit gain, and the operational amplifier N2 is used for converting the gyro differential signal output by the liquid floated gyroscope into a single-ended signal with GND as a reference. The phase-sensitive demodulation circuit includes a full-wave phase-sensitive demodulation circuit and a demodulation reference circuit. The demodulation reference circuit is used for converting the excitation signal generated by an external excitation circuit into a reference signal. The inverting proportional amplification circuit is used for inversely amplifying the single-ended signal with GND as a reference output by the differential amplification circuit. The switch circuit is used for being turned on or turned off under the control of the reference signal, and converting the positive half-wave or the negative half-wave of the amplified single-ended signal with GND as a reference into a positive or negative direct current signal. The demodulation reference circuit comprises resistors R1, R3, R4, a potentiometer RP1, a capacitor C1, an operational amplifier U3C, diodes D1 and D2; the resistors R1 and the potentiometer RP1 are connected in parallel, one end of which is connected to a wire port J1, and the other end is connected to the inverting input terminal of the operational amplifier U3C and one end of the capacitor C1, the other end of the capacitor C1 is connected to the non-inverting input terminal of the operational amplifier U3C and the ground wire GND; the output terminal of the operational amplifier U3C is connected to the diode D2 and the resistor R3 in series; the diode D1 and the resistor R4 are connected in parallel, the positive electrode of the diode D1 is connected to the ground, the negative electrode is connected between the resistor R3 and the resistor R4, and is connected to the input terminal of the switch circuit; the wire port J1 is connected to the external excitation circuit, and the phase of the demodulation reference signal relative to the gyro differential signal can be controlled by adjusting the resistance values of the resistors R1 and the potentiometer RP1; The inverting proportional amplification circuit comprises resistors R7, R5, an operational amplifier U3A, capacitors C18 and C20; the input terminal of the resistor R7 is connected to the output terminal of the differential amplification circuit, and the output terminal is connected to the inverting input terminal of the operational amplifier U3A; the resistors R5 are connected to the output terminal and the inverting input terminal of the operational amplifier U3A respectively; one end of the capacitors C18 and C20 is connected to the ground wire GND respectively, and the other end is connected to the positive power supply terminal and the negative power supply terminal of the operational amplifier U3A respectively; the resistors R7 and R5 are used for adjusting the gain of the circuit, and the operational amplifier U3A is used for inversely amplifying the single-ended signal with GND as the reference output by the differential amplification circuit; The switch circuit comprises an analog switch S1, capacitors C4, C5 and C22; the analog signal positive power supply input terminal VS+ and the analog signal negative power supply input terminal VS- of the analog switch S1 are connected to the ground wire GND through the capacitors C4 and C22 respectively; the normally closed terminal, the normally open terminal and the logic level input terminal are connected to the output terminal of the reverse proportional circuit, the output terminal of the differential amplification circuit and the negative electrode of the diode D1 in the demodulation reference circuit respectively; the ground terminal of the analog switch S1 is connected to the ground wire, the logic level positive power supply input terminal is connected to the ground wire through the capacitor C5, and the output terminal of the analog switch S1 is connected to the input terminal of the direct current amplification and filtering circuit; The analog signal positive power supply input terminal VS+ of the analog switch S1 is also connected to the input terminal of the secondary power supply circuit, the analog signal negative power supply input terminal VS- is also connected to the negative power supply output terminal of the anti-reverse connection filtering circuit, and the logic level positive power supply input terminal is also connected to the output terminal of the secondary power supply circuit.

2. The signal conversion circuit for a liquid floated gyroscope according to claim 1, wherein The secondary power supply circuit is used for separately supplying power to the analog switch S1 in the switch circuit; the secondary power supply circuit comprises capacitors C3, C2 and a voltage stabilizer U2; one end of the capacitors C2 and C3 is connected to the ground wire GND respectively, and the other end is connected to the input terminal Vi and the output terminal Vo of the voltage stabilizer U2 respectively, the input terminal Vi is also connected to the analog signal positive power supply input terminal VS+ of the analog switch S1, and the output terminal Vo is also connected to the logic level positive power supply input terminal of the analog switch S1; the ground terminal of the voltage stabilizer U2 is connected to the ground wire GND.

3. The signal conversion circuit for a liquid floated gyroscope according to claim 2, wherein The direct current amplification filter circuit comprises a resistor R2, a resistor R9, a resistor R10, a resistor R12, a resistor R13, a capacitor C25, a capacitor C19 and an operational amplifier U3D; one end of the resistor R9 is connected to the output end of the switch circuit, the other end is connected to the same-phase input end of the operational amplifier U3D in series with the resistor R10, the resistor R2, the resistor R12 and the resistor R13 are connected in series and then connected to the ground wire GND, and the opposite-phase input end of the operational amplifier U3D is connected between the resistor R12 and the resistor R13; one end of the capacitor C25 is connected between the resistor R9 and the resistor R10, and the other end is connected to the input end of the resistor R2; one end of the capacitor C19 is connected between the resistor R10 and the operational amplifier U3D, and the resistor R13 is used for adjusting the gain of the circuit; The resistor R9, the resistor R10, the capacitor C19, the capacitor C25 and the operational amplifier U3D constitute a same-phase amplification low-pass filter, so that the polarity of the direct current signal output by the phase-sensitive demodulation circuit is consistent with the rotation polarity of the liquid floated gyroscope.

4. The signal conversion circuit for a liquid floated gyroscope according to claim 3, wherein The anti-reverse connection filter circuit comprises a capacitor C23, a capacitor C24, a diode D3 and a diode D4; the capacitor C23 and the capacitor C24 are connected in series, and the positive electrode of the capacitor C24 is connected to the negative electrode of the capacitor C23; the capacitor C23 and the capacitor C24 are connected to output two paths, one of which is connected to the ground, and the other of which is connected to the wiring port J7 provided, and the wiring port J7 is used for connecting the power supply ground of the external power supply; The negative electrode of the diode D3 is connected to the positive electrode of the capacitor C23 and then connected to the input end Vi of the voltage stabilizer U2 in the secondary power supply circuit, the positive power supply port of the operational amplifier N2 in the differential amplification circuit, the positive power supply port of the operational amplifier U3A in the phase-sensitive demodulation circuit, the positive power supply port of the direct current amplification filter circuit and the positive power supply port of the alternating current output circuit; the positive electrode of the diode D3 is connected to the wiring port J5 provided, and the wiring port J5 is used for connecting the positive electrode of the external power supply. The positive electrode of the diode D4 is connected to the negative electrode of the capacitor C24 and then connected to the negative power supply port of the operational amplifier N2 in the differential amplification circuit, the negative power supply port of the operational amplifier U3A in the phase-sensitive demodulation circuit, the analog signal negative power supply input end VS- of the analog switch S1, the negative power supply port of the direct current amplification filter circuit and the negative power supply port of the alternating current output circuit; the negative electrode of the diode D4 is connected to the wiring port J6 provided, and the wiring port J6 is used for connecting the negative electrode of the external power supply.

5. The signal conversion circuit for a liquid floated gyroscope according to claim 4, wherein The alternating current output circuit comprises a voltage follower U3B; the same-phase input end of the voltage follower U3B is connected to the output end of the differential amplification circuit, the output end of the voltage follower U3B is connected to the opposite-phase input end of the voltage follower U3B, so as to convert the output signal of the differential amplification circuit into an alternating current output signal; the output end of the voltage follower U3B is also connected to the wiring port J6 provided, and the wiring port J6 is connected to the signal input end of the external test equipment.

6. The method for conditioning and converting the output signal of a liquid floated gyroscope based on the signal conditioning circuit of any one of claims 1-5, characterized in that, The method comprises the following steps: Step 1: amplifying and converting the differential signal output by the liquid floated gyroscope, and outputting a single-end signal with GND as a reference; Step 2: phase demodulating the single-end signal with GND as a reference, so that the positive and negative half-wave signals in the single-end signal are completely output and converted into direct current signals; At the same time, the single-ended signal with GND as reference is processed by voltage following to obtain an AC output signal for measurement by external test equipment; Step 3: The DC signal output by phase demodulation in step 2 is amplified and filtered to obtain a DC output signal for measurement by external test equipment.

7. A signal conversion device for a liquid floated gyroscope, characterized in that The printed board and the electric connector XP1 are included; the liquid floated gyro signal conversion circuit according to any one of claims 1-5 is fixed on the printed board; The electric connector XP1 has a plurality of power supply interfaces and signal interfaces; one end of the power supply interfaces and signal interfaces is connected with corresponding wiring ports in the liquid floated gyro signal conversion circuit respectively; the other end of the power supply interfaces and signal interfaces is used for connecting external power supply, liquid floated gyro output end and test equipment.

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