54 results about "Instrument amplifier" patented technology

The invention discloses an output voltage detection method and system based on an aviation power supply, and relates to the technical field of aviation power supply voltage detection. A differential voltage sensor is connected to the output end of an aviation power supply, a high-frequency suppression capacitor is connected in parallel, the sampling rate of 20-50 times of the working frequency is set according to the type of the power supply, and the signals are collected and converted into analog voltage signals; the analog signal is subjected to two-stage filtering, is amplified to 0-5V through an instrument amplifier, and is converted into a digital voltage sequence through a 16-bit ADC (Analog to Digital Converter); calculating AC power supply effective value, peak value and other parameters, DC power supply average value, ripple coefficient and other parameters; comparing the characteristic parameters with a preset threshold value, determining that the characteristic parameters exceed the threshold value and recording related information; and a detection result is transmitted to a monitoring terminal through an RS485, data is locally stored, and a switching value is output to an alarm device when the data is abnormal. The method adapts to aviation power supply load fluctuation and environment temperature change, detection precision is high, data transmission and storage are safe, abnormity is accurately identified and early warning is carried out in advance, and aviation power supply operation and maintenance reliability and efficiency are improved.

The invention relates to the technical field of amplifiers, and discloses an analog-to-digital converter combination instrument amplifier which comprises a first-stage amplifier, the first-stage amplifier is in signal connection with a second-stage amplifier, the second-stage amplifier is in signal connection with a front-end low-pass filter (LPF), the front-end low-pass filter (LPF) is in signal connection with an analog-to-digital converter (ADC), and the analog-to-digital converter (ADC) is in signal connection with the analog-to-digital converter. And an unbalanced input-to-balanced differential circuit output module is arranged between the second-stage amplifier signal and a front-end low-pass filter (LPF). From the perspective of signal processing and conversion, a precise signal transition bridge is constructed by adding an unbalanced input-to-balanced differential circuit output module, unbalanced signals output by a second-stage amplifier are converted into double-end balanced differential signals, common-mode noise interference is effectively resisted through a differential transmission mode, the signal purity is guaranteed, and the signal quality is improved. The front-end low-pass filter and the analog-to-digital converter are adaptive to differential signals, so that the signal transmission is stable and anti-interference, and the analog-to-digital conversion is more accurate.

The invention provides a frequency converter embedded current waveform analysis method and system and a medium, and relates to the technical field of current waveform analysis, and the method comprises the steps: obtaining a sampling circuit configured in a current path of a frequency converter; calculating the required total gain based on the original output voltage signal of the sampling resistor and the required input voltage of the analog-to-digital converter; the signal quality of the original output voltage signal is evaluated, the required total gain is dynamically distributed to an instrument amplifier and a programmable gain amplifier, the original output voltage signal is amplified and then passes through an analog-to-digital converter, and current waveform data is obtained for current anomaly analysis; when the signal quality is lower than a first threshold value, the gain share of the instrument amplifier is increased preferentially; when the signal quality is higher than a second threshold, the gain share of the programmable gain amplifier is increased preferentially. According to the invention, the technical problem of low accuracy of current waveform analysis in the prior art can be solved, and the technical effect of improving the accuracy of waveform analysis is achieved.

The invention relates to the technical field of measurement of long-distance and high-accuracy temperature measurement resistors, and particularly discloses a resistor temperature measurement method, which comprises a constant current source I, temperature measurement resistors RX and RY, a reference resistor RR, an analog switch, an instrument amplifier, an analog-to-digital converter and a microcontroller, the method comprises the following specific steps that S1, an analog switch controls a constant current source I to sequentially flow through temperature measurement resistors RX and RY and a reference resistor RR, and current generates a voltage on each resistor and is in direct proportion to the resistance value of the voltage; and S2, measuring the voltages of the temperature measuring resistors RX and RY and the reference resistor RR through an instrument amplifier and an analog-to-digital converter to obtain VX1, the voltage of the temperature measuring resistor RX under the forward current condition, VY1, the voltage of the temperature measuring resistor RY under the forward current condition, and VR1, the voltage of the temperature measuring resistor RR under the forward current condition. According to the resistance temperature measurement method, 0.00025 DEG C or better uncertainty can be obtained, and observable errors caused by thermoelectromotive force can be effectively eliminated.

The application discloses a kind of multi-modal flexible sensor adaptive signal conditioning system design method, belong to flexible sensor signal conditioning technical field.The present application overcomes the defects of poor universality, performance compromise, high cost of mass production of existing conditioning circuit, adopts layered decoupling and dynamic reconstruction system-level architecture: through multi-modal feature analysis and demand mapping modeling, the feature vector composition of scene recognition is determined;Design configurable analog front end, integrate instrument amplifier, transimpedance amplifier, charge amplifier, bridge amplifier four parallel processing sub-modules, wherein charge and bridge amplifier adopt self-designed architecture with dynamic adaptive gain adjustment capability;Build heterogeneous digital processing platform with NPU, CPU, DSP as core, through cross-modal data fusion, scene recognition engine, dynamic hardware configuration combined with feedforward and feedback, loadable algorithm library and closed-loop optimization control law, realize the real-time scene reconstruction of hardware parameters and digital algorithm;Combined with domestic single-chip selection, rigid-flex PCB and automatic calibration, meet the demand of low-cost mass production.The present application realizes the native adaptation and performance optimization of single hardware platform to voltage, current, charge, impedance and other types of sensor signals, and can be widely applied in robot dexterous hand, medical monitoring, intelligent bandage, consumer motion monitoring and industrial monitoring fields.

The application provides a kind of hollow core polarization maintaining optical fiber cutting machine tension control system and control method, belong to optical fiber cutting control technical field, system uses four layers architecture of perception layer, processing layer, control layer, execution layer: perception layer is measured by double strain gauge symmetrical compensation device and temperature sensor synchronous acquisition mechanics and environmental signal;Processing layer adopts Wheatstone bridge, instrument amplifier, low-pass filter, 16-bit ADC and temperature compensation unit to realize signal multistage conditioning;Control layer deploys feedforward adaptive PID compound control system, combined with optical fiber diameter-tension parameter library feedforward compensation and dynamic PID adjustment, and integrates step loading control and fault early warning mechanism;Execution layer adopts torque mode motor and outputs linear tension through lead screw mechanism.

A kind of parallel machine current adding system belongs to the technical field of electronic equipment for measurement and testing, solve how to design a kind of hardware circuit simple, control precision high parallel machine current adding and system problem;The parallel machine current adding and system of the present application, comprising: multiple single machine current sampling circuits, parallel machine current adding and circuit;Single machine current sampling circuit includes: first differential amplifier circuit, first proportional regulating circuit, first unit inverter circuit, first digital potentiometer;Parallel machine current adding and circuit includes: instrument amplifier circuit, second proportional regulating circuit, second unit inverter circuit, second digital potentiometer and multiple proportional input end resistance;Digital potentiometer is applied to parallel machine circuit, and the resistance value of potentiometer is assigned by the number of parallel machine table set to realize the adjustment of amplification factor, replace the single proportional resistance resistance value of traditional resistance proportional circuit to realize the adjustment of amplification factor, hardware circuit is simple, amplification factor control is accurate.

The invention belongs to the field of integrated circuits, and discloses a low-voltage high-precision instrumentation amplifier analog IC (integrated circuit) chip which takes a high-performance reference current source circuit without an operational amplifier as a biasing circuit. In the low-voltage design, in order to solve the problem that the signal-to-noise ratio of the instrument amplifier is gradually deteriorated, a rail-to-rail input and output structure is adopted. According to the invention, the folded cascode structure provides a large gain and also serves as a resistor to be connected with the Miller compensation capacitor to form an unconventional RC network, so that the zero point problem is ingeniously solved, the additional chip area is not increased, and the response speed of the instrument amplifier is also improved; the MOS capacitor is used as the compensation capacitor, compared with a traditional metal capacitor, the MOS capacitor has the advantages of being high in integration level, small in area and the like, and the chip area is greatly reduced while the compensation effect is achieved.

The utility model discloses a kind of multi-loop processing CV mode electronic load instrument, it includes main control module, main power module, auxiliary power module, display module, button module, power amplifier module, communication board module and interface module.Main control module is core control unit, contains instrument amplifier, and difference proportional circuit, integrated operational amplifier circuit, advance adjustment circuit, lag adjustment circuit and analog switch, different input signal characteristics are adapted by flexible switching adjustment mode.The main power module and auxiliary power module provide stable power supply respectively;Display module and button module form man-machine interface;Power amplifier module drives high-power MOS tube to maintain constant voltage output;Communication board module supports multiple communication protocols;Interface module provides physical connection port for external equipment.The utility model significantly improves system stability and adaptability through multi-loop design, suitable for a variety of application scenarios.

The invention relates to the technical field of electromagnetic positioning, in particular to a five-degree-of-freedom sensor for electromagnetic positioning and an induction signal processing system, and the induction signal processing system adopts a three-stage circuit architecture: the first stage is an instrument amplifier pre-amplification circuit with input filtering and common-mode suppression functions; the low-noise amplifier is used for performing low-noise amplification on a microvolt-level original signal; the second stage is a Sallen-Key type active high-pass filter circuit and is used for suppressing power frequency and low frequency interference; and the third stage is a Sallen-Key type active low-pass filter circuit which is used for filtering high-frequency noise. Wherein the output of the pre-amplification circuit is connected to the third-stage low-pass filter circuit and then is cascaded with the second-stage high-pass filter circuit to jointly form a band-pass filter path, and finally, a stable analog signal with a high signal-to-noise ratio is output. The problems that a micro sensor is weak in signal, prone to interference and high in system complexity are effectively solved, and the performance and reliability of the electromagnetic positioning system in high-precision application scenes such as medical navigation and virtual reality are remarkably improved.

The invention discloses a strong PUF (Physical Unclonable Function) circuit for security protection of the Internet of Things, which comprises two TMR sensor arrays, two instrumentation amplifiers, two switched capacitor integrators and a comparator, and is characterized in that each TMR sensor array comprises a plurality of TMR sensor units, and the conduction number of the TMR sensor units in the two TMR sensor arrays is controlled through an excitation signal; two differential voltage signals are generated, two instrument amplifiers respectively carry out differential amplification on the two differential voltage signals to generate amplified voltage signals, two switched capacitor integrators respectively carry out sampling and accumulation on the amplified voltage signals to obtain sampled voltage signals, and the sampled voltage signals are output to a comparator. The comparator carries out voltage polarity judgment on the two sampling voltage signals to obtain a PUF response; the method has the advantages of high uniqueness and randomness, high stability, low bit error rate and high excitation-response pair number, and can meet the requirements of a high-reliability large-scale security authentication system.

The invention relates to the technical field of intelligent pots, and particularly discloses a temperature control system and method for an intelligent pot, and the system comprises a temperature collection module which comprises a temperature sensor and a signal conditioning circuit, and the signal conditioning circuit comprises an instrument amplifier and a low-pass filter which are electrically connected in sequence, the output end of the temperature sensor is electrically connected with the input end of the instrument amplifier; the signal input end of the core control unit is electrically connected with the output end of the low-pass filter; the power adjusting module comprises a PWM generating circuit and a power driving circuit, the control end of the PWM generating circuit is electrically connected with the PWM output end of the core control unit, and the input end of the power driving circuit is electrically connected with the output end of the PWM generating circuit; the self-adaptive power management unit comprises a DC-DC conversion circuit, and the DC-DC conversion circuit is electrically connected with the temperature acquisition module, the core control unit and the power regulation module; the problems that a temperature control system of an intelligent pot is unstable in structure, inaccurate in temperature measurement and weak in anti-interference capacity are solved.

The application discloses an output voltage detection method and system based on an aviation power supply, and relates to the technical field of aviation power supply voltage detection; a differential voltage sensor is connected to the output end of the aviation power supply, a high-frequency suppression capacitor is connected in parallel, a sampling rate of 20-50 times the working frequency is set according to the type of the power supply, analog voltage signals are collected and converted, two-stage filtering is performed on the analog signals, the analog signals are amplified to 0-5V by an instrument amplifier, and then the analog signals are converted into digital voltage sequences by a 16-bit ADC; the effective value, peak value and other parameters of the alternating-current power supply, the average value, ripple coefficient and other parameters of the direct-current power supply are calculated; the characteristic parameters are compared with preset threshold values, and if the characteristic parameters exceed the threshold values, it is determined that an abnormality occurs and relevant information is recorded; the detection results are transmitted to a monitoring terminal through RS485, data is stored locally, and when an abnormality occurs, an output switch quantity is output to an alarm device. The application is adapted to aviation power supply load fluctuation and environmental temperature change, has high detection precision, safe data transmission and storage, can accurately identify an abnormality and give an early warning, and improves the reliability and efficiency of aviation power supply operation and maintenance.

This invention provides an electrocardiogram (ECG) instrument amplifier circuit and an ECG signal acquisition system. In the ECG instrument amplifier circuit provided by this invention, a first terminal of a first capacitor scaling circuit is connected to the first output terminal of the instrument amplifier; a second terminal of the first capacitor scaling circuit is connected to the first terminal of a first neutralizing capacitor array; the second terminal of the first neutralizing capacitor array is connected to the first terminal of a first switch; and the second terminal of the first switch is connected to the first input terminal of the instrument amplifier. A second capacitor scaling circuit has its first terminal connected to the second output terminal of the instrument amplifier; its second terminal is connected to the first terminal of a second neutralizing capacitor array; the second terminal of the second neutralizing capacitor array is connected to the first terminal of a second switch; and the second terminal of the second switch is connected to the second input terminal of the instrument amplifier. A parasitic capacitance calibration circuit is connected to both the first and second input terminals of the instrument amplifier. This ECG instrument amplifier circuit can significantly improve the input impedance of the instrument amplifier.

The present invention provides a double-ended output circuit and a signal processing circuit based on a single-ended signal source, in which the signal processing circuit based on the single-ended signal source is configured to amplify an original signal in a single-ended signal form output by the single-ended signal source with an instrumentation amplifier (In-Amp), so as to utilize the high input impedance of the instrumentation amplifier and improve the signal processing efficiency. Complete and high-precision amplification processing is carried out on an original signal in a single-ended signal form output by the single-ended signal source by virtue of the native advantages of high common-mode rejection ratio, high gain adjustment precision, low temperature drift, good linearity and low noise; therefore, weak signals in original signals output by the single-ended signal source can be effectively captured, and the reliability of a corresponding sensing device adopting the signal processing circuit based on the single-ended signal source is guaranteed correspondingly when the single-ended signal source is a corresponding sensing device.

The application belongs to the technical field of analog integrated circuits, and particularly relates to a capacitive coupling chopping instrument amplifier with enhanced input impedance. The self-calibration gate voltage self-boosting charging circuit and the self-zeroing auxiliary operational amplifier are designed in a function complementary and time sequence cooperative mode, and a principle breakthrough is realized through the function complementary and time sequence cooperation. The self-calibration gate voltage self-boosting charging circuit completes high-speed dynamic voltage building at the chopping switching moment, and solves the problem of insufficient building speed of the traditional auxiliary operational amplifier. The self-zeroing auxiliary operational amplifier completes static precision calibration and noise suppression, and eliminates the establishment error of the gate voltage self-boosting and the noise of the auxiliary circuit. The two cooperate to simultaneously realize rapid, high-precision and low-noise establishment of the input capacitor under low power consumption, so that the system obtains a G omega order super-high input impedance, and the high input impedance, low noise and low power consumption are cooperatively optimized, which breaks through the inherent design bottleneck in the industry.

The invention discloses a graphene aerogel vibration sensor signal acquisition system and method, and belongs to the technical field of sensor signal acquisition, and the system comprises a Wheatstone bridge module which is used for converting mechanical vibration sensed by a graphene aerogel sensor into a microvolt differential voltage signal; the instrument amplifier is used for converting the differential voltage signal into an amplified voltage signal with adjustable gain; the second-order low-pass filtering module is used for filtering high-frequency noise of the amplified voltage signal and outputting a filtered signal; the impedance optimization module is used for executing an adaptive impedance matching algorithm based on the characteristics of the filtered signal, dynamically adjusting the input impedance of the system and outputting an impedance-matched signal; the analog-to-digital conversion module is used for converting the impedance-matched signal into a digital signal and outputting the digital signal to an upper computer; according to the invention, through the multi-stage noise suppression strategy and the precise adaptation with the characteristics of the sensor, the acquisition precision of the weak vibration signal and the system robustness are significantly improved.

The utility model relates to a temperature compensation circuit of a piezoresistive pressure sensor and the piezoresistive pressure sensor, a Wheatstone bridge adopts a constant voltage power supply mode, and the power supply current of the Wheatstone bridge is sampled as a positive feedback signal to compensate the temperature drift of the pressure sensor. The output voltage of the instrument amplifier returns to zero through the zeroing unit when the measured pressure is zero, and the output voltage (unit is millivolt) of the instrument amplifier is just the pressure value (unit is kilopascal) detected by the pressure sensor through the gain resistor, so that the direct reading of the pressure detected by the sensor is realized.

The invention discloses a sensor circuit, a sensor and a sensor fault detection method, relates to the technical field of power electronics, and realizes sensor fault detection. The sensor circuit comprises a bridge circuit, an instrument amplifying circuit, a first current-limiting resistor and a control unit, the input end positive electrode of the bridge circuit is electrically connected with a power supply, and the input end negative electrode of the bridge circuit is grounded through the first current-limiting resistor; the output end of the bridge circuit is electrically connected with the input end of the instrument amplification circuit; and the output end of the instrument amplification circuit and the negative electrode of the input end of the bridge circuit are electrically connected with the control unit.

The invention discloses a nondestructive testing system and method for weak eddy current signals. When a detected target object exists, output voltage signals of the two TMR sensors are amplified through the multi-path instrument amplifier, double-end differential output is converted into single-end output, then the two paths of output signals are offset through the strong and weak weighting operation circuit, and the rest path of voltage signal is output. The value of the background signal is reduced to highlight the weak change voltage, and the proportion of the voltage change brought by the weak eddy current signal under the background signal is increased; by adopting an amplifying circuit and a filtering circuit, filtering processing is carried out while the voltage signal is amplified, so that disturbance on the signal is as small as possible, a required frequency band is effectively separated from a complex signal, and meanwhile, unnecessary frequency components are inhibited; therefore, the signal quality is improved, and the detection accuracy is enhanced.

An instrumentation amplifier with electronically adjustable gain is disclosed. The gain is adjusted by electronically controlling a resistor coupled to a feedback portion of the instrumentation amplifier. The resistor is adjusted by a switch controlled by a resistor-controlled signal referenced by a common-mode voltage present at the input of the instrumentation amplifier. Thus, the instrumentation amplifier can accommodate a high range of common-mode voltages while still providing controllable gain.

The utility model relates to a track circuit comprehensive tester, which comprises a shell, an analog signal processing circuit, a main control unit, a display unit, a power supply module, an input unit and a communication module are arranged in the shell, the analog signal processing circuit comprises a banana head jack and an instrument amplifier, the banana head jack is connected with a meter pen wire and a current clamp, and the banana head jack is connected with the current clamp. The main control unit is in communication connection with the display unit, the main control unit is electrically connected with the input unit, the main control unit is in communication connection with the communication module, and the power supply module is electrically connected with the main control unit, the display unit and the communication module; four circular through holes corresponding to the banana head jacks are formed close to the upper end of the side face of the shell, and a display unit and an input unit are embedded in the middle of the front face of the shell. The circuit is simple in structure, small in size, convenient to carry due to the arrangement of the shell, and convenient to operate due to the arrangement of the display unit and the input unit.

The application provides a frequency converter embedded current waveform analysis method, system and medium, relates to the technical field of current waveform analysis, and the method comprises the following steps: acquiring a sampling circuit configured in a current path of a frequency converter; based on an original output voltage signal of a sampling resistor and a required input voltage of an analog-to-digital converter, calculating a required total gain; evaluating the signal quality of the original output voltage signal, dynamically allocating the required total gain to an instrument amplifier and a programmable gain amplifier, amplifying the original output voltage signal, and then inputting the original output voltage signal into the analog-to-digital converter to obtain current waveform data for current anomaly analysis; when the signal quality is lower than a first threshold value, the gain share of the instrument amplifier is preferentially increased; and when the signal quality is higher than a second threshold value, the gain share of the programmable gain amplifier is preferentially increased. Through the application, the technical problem of low current waveform analysis accuracy in the prior art can be solved, and the technical effect of improving waveform analysis accuracy is achieved.

The invention provides a capacitive coupling chopping instrument amplifier based on improved pseudo resistor bias. The capacitive coupling chopping instrument amplifier comprises main operational amplifiers GM1 and GM2, a ripple suppression module and two groups of closed-loop bias pseudo resistors. The closed-loop bias pseudo resistors adopt complementary CMOS structures (DNW-NMOS and PMOS are connected in a back-to-back manner) and are matched with the unity gain auxiliary operational amplifier to form a dynamic compensation network, the first closed-loop bias pseudo resistor is connected with the positive input end and the negative output end of the GM1, the second closed-loop bias pseudo resistor is connected with the negative input end and the positive output end of the GM1, and the second closed-loop bias pseudo resistor is connected with the negative input end and the positive output end of the GM1. The unity gain auxiliary operational amplifier detects and compensates the voltage difference between the two ends of the pseudo resistor in real time and suppresses direct current offset and offset voltage, and an open-loop bias pseudo resistor is integrated in the ripple suppression module, so that high-frequency ripples can be filtered out, and stable common-mode bias signals can be provided for the GM2. According to the design, the linearity and the high-pass cut-off frequency stability of the amplifier are remarkably improved by optimizing the pseudo resistance bias structure, and the amplifier is suitable for collecting weak low-frequency signals such as bio-electricity signals.

The invention discloses a linear Hall sensor and a temperature compensation method thereof. The linear Hall sensor comprises a Hall piece, a chopping modulation switch circuit, a first-stage instrument amplifier, a chopping demodulation switch circuit and a second-stage instrument amplifier. The chopping modulation switch circuit is used for carrying out chopping modulation on output voltages in two diagonal directions of the Hall piece; the first-stage instrument amplifier is used for amplifying the differential Hall voltage signal which is subjected to chopping modulation by the chopping modulation switching circuit; the chopping demodulation switch circuit is used for demodulating the modulation signal amplified by the first-stage instrument amplifier; and the second-stage instrument amplifier is used for further amplifying the Hall voltage signal obtained by the chopping demodulation switching circuit to obtain a voltage amplification factor changing along with the temperature, so that the voltage amplification factor changing along with the temperature of the Hall voltage signal is counteracted with the Hall voltage change caused by the temperature coefficient of the Hall piece. The precision and the stability of the linear Hall sensor can be improved.

The application relates to a lumbar force line dynamic monitoring and visual feedback system based on foot pressure sensing, relates to the field of intelligent medical rehabilitation apparatuses and wearable devices, and comprises intelligent shoes and a mobile terminal. A pressure sensor array in the intelligent shoes acquires dynamic pressure distribution data of each region of the foot bottom in real time, sequentially transmits the data to a microcontroller after signal acquisition through a multiplexing switch, signal amplification through an instrument amplifier and analog-digital conversion through an analog-digital converter, and sends the pressure distribution data to the mobile terminal through a wireless communication module after processing by the microcontroller. An alarm execution unit receives a control instruction sent by the microcontroller and issues an alarm prompt. A rechargeable lithium battery supplies power for the system, and a power management module provides a stable working voltage for the system. The application converts lumbar load risk into a visual image of foot pressure distribution through foot pressure sensing, realizes home, dynamic and non-invasive monitoring of the lumbar load and instant posture intervention.

The application discloses a kind of measurement method and system for improving the precision of differential resistance sensor, comprising: control constant current flows through reference resistance R S , differential resistance sensor resistance R1 and differential resistance sensor resistance R2;The voltage generated on reference resistance R S , differential resistance sensor resistance R1 and differential resistance sensor resistance R2 is introduced into instrument amplifier, and AD code value AD S , AD code value AD1 and AD code value AD2 are obtained using ADC converter;Using AD code value AD S , AD code value AD1 and AD code value AD2 calculate measurement parameter Z′;The measurement parameter Z′ is the difference between differential resistance sensor resistance R1 and differential resistance sensor resistance R2 is the sum of differential resistance sensor resistance R1 and differential resistance sensor resistance R2;Without changing the structure of existing differential resistance sensor, the sensitivity of the sensor is improved, and the linearity of the sensor is improved.

The invention discloses a high-input-impedance and low-noise capacitive coupling chopping instrument amplifier. The high-input-impedance and low-noise capacitive coupling chopping instrument amplifier comprises a main amplifier, a positive feedback loop, a pre-charging circuit and a direct-current servo loop. A positive feedback loop and a pre-charging technology are adopted, current flowing into an input capacitor Cin from a signal source is reduced through current compensation, and input impedance is improved. The positive feedback loop and the negative feedback loop share one chopper, so that the use of one chopper is reduced, and the layout area is reduced; the pre-charging circuit can take an amplifier with smaller power consumption as a buffer so as to reduce the power consumption of the system. Furthermore, a multi-rate duty ratio resistor is used as a large resistor of the integrator instead of a pseudo resistor, so that the noise introduced by the direct-current servo loop can be reduced. The circuit is good in performance, and has the advantages of high input impedance, low noise and low power consumption.

The invention discloses a sensor-based multi-channel bridge measuring device, which comprises a signal acquisition module, a signal conditioning module, a data processing module and a communication interface module, and is characterized in that the signal acquisition module is composed of 8-32 independent bridge circuits, each bridge circuit is connected with a resistance strain type sensor, and a full-bridge or half-bridge structure is adopted; the signal conditioning module comprises a multiplexer, an instrument amplifier and a filter circuit; and the multiplexer adopts a low-on-resistance analog switch. According to the multi-channel bridge measuring device based on the sensor, through multi-channel synchronous measurement (8-32 channels can be selected), the problem that a traditional device is low in single-point measurement efficiency is solved, the detection efficiency is improved, and through multiple anti-interference design (optoelectronic isolation, shielding and a filtering algorithm), the detection efficiency is improved. The problem of industrial field noise interference is solved, and measurement precision is guaranteed.

The invention relates to an ultra-stable crystal oscillator short-term stability system, which comprises a temperature measurement amplification circuit, which is used for acquiring a voltage difference between a thermistor and a temperature setting resistor through a balanced bridge in a three-operational-amplifier instrumentation amplifier, amplifying the voltage difference through a differential amplifier to obtain a temperature control voltage carrying offset voltage information, and sending the temperature control voltage to the temperature control amplification circuit; the signal is output to the second-stage amplification circuit; the thermistor is used for collecting the temperature of the ultra-stable crystal oscillator thermostatic bath; the temperature change compensation circuit is used for finely adjusting a temperature inflection point set value of an instrument amplifier in the temperature measurement amplification circuit, compensating frequency change caused by temperature gradient change of the thermostatic bath at high and low temperatures, and improving the stability of output frequency; the second-stage amplifying circuit is used for amplifying and outputting the difference between the standard reference voltage Vref and the temperature control voltage Vt; the error feedback control circuit is used for correcting the control voltage output by the two-stage amplification circuit to obtain a benchmark reference voltage Vref, so that the benchmark reference voltage Vref is dynamically adjusted according to temperature change, and system errors and error control voltage introduced by operational amplifier drift are reduced; and the power tube is used for heating the ultra-stable crystal oscillator thermostatic bath.