271 results about "Instrument amplifier" patented technology

The invention relates to a capacitive micro-accelerometer which adopts the design of a bulk-silicon processed micro-mechanical structure and the design of an integrated circuit, which pertains to the field of MEMS micro-inertial instruments. The capacitive micro-accelerometer adopts two chips of a micro-mechanical sensor and a signal processing circuit for respective integration, the capacitive micro-accelerometer is carried out by the overall packaging and finally realizes an internal structure of the packaged system; the micro-mechanical sensor of the invention adopts a full-differential micro-mechanical structure sensitive element to be matched with a follow-up circuit; the signal processing circuit comprises a full-differential switched capacitor charge amplifier front-end circuit module with adjustable gain, a back-end cascade circuit module which is composed of a first-order switched capacitor low-pass filter and an instrument amplifier and an auxiliary circuit module which is composed of a reference voltage and bias current generating circuit, a self-test circuit and a clock generating circuit. The two-chip proposal of the system of the invention carries out the respective integration and overall packaging, thus simplifying the complexity of the system, reducing the processing cost and the difficulty and improving the performance and the yield.

In a single-ended or differential instrument amplifier, an input offset may be adjusted by driving current into the impedance of a feedback network of the amplifier. The amplifier may be provided with programmable gain capability. The impedance does not change with different gain settings, such that the input offset adjustment is equal for all gains. The amplifier may receive the output of a sensor such as, for example, a gas detector such as a thermal conductivity detector. The gas detector may be utilized to measure a gas flowing from a gas source such as, for example, a chromatographic column.

The invention discloses a multi-channel data acquisition device for a submarine pipeline magnetic flux leakage internal detector. The multi-channel data acquisition device comprises a hall sensor, a multi-path switch, an instrument amplifier, an analog-to-digital (AD) conversion module, a field programmable gate array (FPGA), a digital signal processor (DSP) and a secure digital memory (SD) card, wherein the multi-path switch has a two-stage series structure; the multi-channel data acquisition device is provided with heat insulation cotton so as to adapt to a specific high-temperature and high-corrosion environment of a submarine pipeline; the hall sensor converts the magnetic induction density into voltage; the voltage is switched by the multi-path switch, so that a signal is transmitted to the instrument amplifier; the instrument amplifier amplifies a weak signal; the AD conversion module sets sampling for eight times through software, performs analog-to-digital conversion, and transmits a digital value to the FPGA after the conversion; and the DSP receives FPGA cached data, digitally filters and compresses the cached data, and finally stores the data into the SD card. Due to a dual central processing unit (CPU) structure consisting of the FPGA and the DSP, a large amount of data can be stored and processed; the device has the characteristics of high speed, multiple channels, high resolution and the like; furthermore, pipeline transportation safety is guaranteed; and early maintenance is facilitated.

The invention relates to a giant magnetoresistive effect current sensor using an amorphous alloy magnetic ring structure, and belongs to the technical field of power system measurement. In the current sensor, a wire to be measured passes through an amorphous alloy magnetic ring; and a direct current magnetic biasing coil is wound on the amorphous alloy magnetic ring and is powered by a direct current constant current source. A plurality of layers of giant magnetoresistive effect chips are arranged in an air gap of the amorphous alloy magnetic ring. Positive output ends and negative output ends of the chips are connected with the in-phase input end and the inverted input end of an instrument amplifier respectively; and an output end of the instrument amplifier is connected with an in-phase input end of an operational amplifier. A voltage following resistor is connected in parallel between an inverted input end and an output end of the operational amplifier; the output end of the operational amplifier is connected with an input end of an analog / digital converter; and an output end of the analog / digital converter is connected with a nixie tube display. The current sensor has the advantages of small size, low cost, low energy consumption, wide frequency response, high sensitivity, stabile characteristic and the like, and meets the requirements of environmental friendliness, energy conservation and large-scale distributed monitoring in a novel intelligent power grid.

The invention provides a wide-range broadband current sensor base on a tunnel magnetic resistance effect, and belongs to the field of sensing measurement. The sensor comprises an open magnet ring, current sensing chips, a compensation coil, a sampling resistor, an instrument amplifier, a zeroing circuit, a current output module and a power supply module; the current sensing chips include a high-sensitivity TMR sensing chip and a low-sensitivity TMR sensing chip, and are provided with two current measuring output points; the open magnet ring sleeves a current carrying lead, so that the current carrying lead penetrates through an inner hole of the open magnet ring; the compensation coil is wound around the open magnet ring; the high-sensitivity TMR sensing chip is arranged in an open air gap position of the open magnet ring; the low-sensitivity TMR sensing chip is arranged outside the open magnet ring; the high-sensitivity TMR sensing chip with other composition parts forms a closed loop structure; and the low-sensitivity TMR sensing chip, the instrument amplifier and the zeroing circuit form an open loop structure. The current sensor has the advantages of being wide in measuring range, wide in frequency band, small in size, high in precision, low in cost, free of intrusion and convenient to install and maintain.

The invention discloses a method and a device for precisely measuring temperatures of platinum resistors. The scheme for measuring the temperatures of the micro-current-drive four-wired Pt100 platinum resistors includes that the device for precisely measuring the temperatures of the platinum resistors comprises a constant-current source drive circuit, a four-wired platinum resistor interface circuit, an instrument amplifier circuit, an anti-aliasing filter circuit, a sampling hold circuit, an A / D (analog / digital) sampling circuit and a single chip microcomputer system. A constant-current source comprises two low-noise and low-offset bipolar operational amplifiers OP07CD with high open-loop gain; the four-wired platinum resistor interface circuit is divided into a constant-current source power lead and a voltage drive lead; the instrument amplifier circuit comprises a double-stage differential amplifier circuit; the anti-aliasing filter circuit is an RC low-pass filter circuit; an A / D converter is a 24-bit high-resolution A / D converter CS5550. The method and the device have the advantage that the measurement precision is high, calibrated temperature measurement errors are smaller than + / -0.03 DEG C, and requirements of industrial production procedures on high temperature measurement precision can be met.

A loudspeaker enclosure is disclosed which includes a horizontal bottom wall, front wall means and parallel spaced vertical side walls connected with the bottom wall. The front wall means include an adjustable baffle board with at least one opening for mounting a loudspeaker and a horizontal top wall is connected with the upper edges of the front wall means and the side wails. Electronic components of a musical instrument amplifier may be mounted into the upper section of the enclosure. The invention is characterized by the provision of said adjustable baffle board which can be vertically tilted backwards or, as an alternative, sidewise to change the listening axis from the loudspeaker to the listener for optimum directional sound quality. The enclosure further has either at least four contact members or defines one complete contact surface relative to a support surface to let vibrational energy propagate freely throughout the cabinet and be transferred to said support surface, thus causing additional vibration therein. The user may reorient the baffle board depending upon the position of the loudspeaker relative to the listeners ear level without cutting off the transmission of structure-born sound from the cabinet to the support surface.

The invention discloses a low-voltage test circuit and a low-voltage test method for an initiating explosive device. The method comprises the following steps of: (1) disconnecting a high-voltage control loop of the initiating explosive device, and applying test excitation voltage to the low-voltage test circuit; (2) converting low-voltage differential signals on a resistor R1 and a resistor R2 of a double-bridge wire initiating explosive device into a single-ended output signal by using an instrument amplifier, amplifying, outputting to a filter, filtering the signal by using the filter, and outputting comparison voltage Ub; (3) amplifying low-voltage differential signals on a detection resistor R5, a detection resistor R6 and a detection resistor R7, converting and filtering to generate three reference comparison voltages, namely U0.3, U0.8 and U2.0; (4) comparing the Ub with the U0.3, the U0.8 and the U2.0 by using three comparators respectively; and (5) determining the current state of the initiating explosive device through a comparison result. The low-voltage test circuit is simple and reliable, a small number of elements are used, a test loop is not required to be charged with accurate current, the circuit does not have parameters required to be adjusted, and the judgment method is simple.

The invention relates to an on-chip all-in-one micro integrated magnetic sensor, which consists of a Hall part, a dynamic imbalance eliminating circuit, a hysteresis comparison circuit, a logic control and oscillator circuit and an H-bridge output circuit, wherein the logic control and oscillator circuit provides two complementary clock signals CLK1 and CLK2 which are obtained by inverting the same clock signal; the dynamic imbalance eliminating circuit comprises an instrument amplifier and a sampling capacitor, under the clock signals CLK1 and CLK2, a voltage signal of the Hall part is inputted into the instrument amplifier, and the hysteresis comparison circuit is of a Schmidt trigger circuit. When CLK1 is adopted as the clock signal and CLK1 signal is high, the output of the hysteresiscomparison circuit is maintained; and when CLK1 signal is low, the output of the dynamic imbalance eliminating circuit is compared with the reference voltage of the hysteresis comparison circuit. Thestability of the circuit performance is good, the production cost is low, the production links and the test links are reduced, the encapsulation difficulty is reduced, and the automatic industrialized mass production can be realized.

The invention relates to a sensor signal amplifying and conditioning circuit which comprises an instrument amplifier, a same-phase scale amplifier and a voltage follower, wherein the input end of the instrument amplifier is connected with a differential input signal; the voltage follower inputs the reference voltage into the reference voltage end of the instrument amplifier; the output signal of the instrument amplifier is accessed to the same-phase input end of the same-phase scale amplifier; the reverse-phase input end of the same-phase scale amplifier is used as a gain adjusting end; and the output end of the same-phase scale amplifier is used as the output end of the whole sensor signal amplifying and conditioning circuit. The invention is used for amplifying the small differential signal sent by the sensor and converting the differential signal into the single-end signal output to the reference end. By arranging the external resistor, the invention can realize zero-point and gain adjustment, extend the application range, and complete the impedance matching through the voltage follower.

The invention relates to a biphase digital phase-locking amplifier (as shown in chart 1) and a digital domain synchronous phase-locking algorithm of the biphase digital phase-locking amplifier. The biphase digital phase-locking amplifier can be used for detecting weak current signals, and realize the functions of automatic filtering tracking and synchronous phase-locking. The biphase digital phase-locking amplifier can solve the problems that the volume of the existing phase-locking amplifier is large, the temperature excursion exists, and the speed is slow when the existing phase-locking amplifier is connected with a computer to carry out automatic measurement and control. The biphase digital phase-locking amplifier has the technical characteristics that the weak current signals pass through a 9-step RLC (radio link control) mixed type high-pass filter by a precise I / V conversion circuit, and is then connected with two low-noise instrument amplifiers, the connecting modes of which are different; the rear ends of the instrument amplifiers are respectively connected with an 8-step RLC mixed type high-pass filter, and a differential signal is formed by signals output by two low-pass filters. Meanwhile, reference signals pass through a 90-degree phase shifter of a phase-locking loop to output two TTL square waves, the phase difference of two phases of which is 90 degrees. Signals of three paths are collected by a data acquisition card, and are then transmitted to a PC (personal computer) machine. The biphase digital domain synchronous phase-locking algorithm (as shown in chart 2) provided by the invention is applied on the PC machine to carry out signal processing and filtering.

The invention discloses a circuit for detecting dynamic weak capacitance of a micro electro mechanical system (MEMS) device, which is mainly applied to change detection of dynamic weak capacitance in a capacitive MEMS device. The circuit comprises a driving signal generation circuit, a capacitance to voltage (C / V) converting unit, a primary sampling and holding unit, a secondary sampling and holding unit and a signal processing unit. The driving signal generation circuit performs self-oscillation to generate a sine wave signal with fixed amplitude and frequency, and provides a detection pumping signal for the C / V converting unit; the C / V converting unit converts the weak capacitance variation into voltage, and a sine wave signal which can be processed by the subsequent stage of a samplingand holding circuit is output by an instrument amplifier; and the primary sampling and holding unit detects a positive peak point of the input sine wave, and when the positive peak point is detected,the output signal keeps the voltage of the positive peak point and half sine wave cycle is kept unchanged, the latter half cycle changes along with the input signal, and the output signal is used as a signal to be detected of the secondary sampling and holding unit.

The invention discloses a fully differential force balance mode MEMS acceleration sensor signal processing circuit comprising a fully differential switched capacitor circuit, a sampling and holding circuit, an instrument amplifier, a multiphase clock circuit and a reference source circuit. The fully differential switched capacitor circuit detects the MEMS change capacitance and outputs differential signals to be connected with the instrument amplifier through the sampling and holding circuit, and the differential signals are converted into single-end output signals through the instrument amplifier. According to the acceleration sensor signal processing circuit, high-precision and low-noise voltage output can be realized; and the designed acceleration sensor signal processing circuit works in a force balance second-order simulation closed-loop system and can convert the output voltage of the front-end detection circuit into electrostatic force to be fed back to the intermediate pole plate so that the mass block is maintained to vibrate near the balance position, and thus the circuit has high sensitivity.

The invention discloses an underwater data recorder system low in power consumption and belongs to the technical field of underwater sound communication. The data recorder system can collect underwater sound signals and store the signals into a storage module in the data recorder system, can be used in the deep sea environment conveniently and is low in power consumption. The data recorder system specifically comprises an underwater sound signal collecting module, a pre-amplifier, a filter, a pressure sensor, an instrument amplifier, a controller, the storage module and a power source. The underwater sound signal collecting module is used for collecting the underwater sound signals, the collected underwater sound signals are amplified and filtered, then the controller carries out A / D conversion on the underwater sound signals, and the underwater sound signals are written into the storage module through a set format. The pressure sensor is used for collecting pressure data of the working environment of a data recorder so as to obtain the actual depth of underwater working of the data recorder. The system reduces the power consumption of the data recorder by managing the work mode and the work procedure of the data recorder with the lower power consumption, and therefore the data recorder can work independently underwater for a long time.

A closed-loop heater control circuit for use with integrated circuit thermal sensing devices, such as thermal accelerometers, is disclosed. The heater control circuit includes a switched-capacitor integrating circuit and a controller or modulator. The switched-capacitor integrating unit integrates a common-mode voltage signal from an instrument amplifier with respect to an analog common reference voltage. In operation, the switched-capacitor integrating unit is adapted so that the closed-loop is opened briefly at the beginning of every new cycle, e.g., using an enable signal, during fast start-up or power-down.

The invention belongs to the technical field of amplifiers, and particularly relates to a current feedback chopper modulation instrument amplifier working under a micro quiescent current. The amplifier consists of a blocking condenser, a current feedback chopper amplifier, an N-bit mismatch compensation capacitor array, a ripple canceling circuit, a biasing circuit and a clock frequency dividing circuit. The microcurrent and current feedback chopper modulation instrument amplifier has the characteristics of alternating current coupling, high input impedance, ultra-low offset voltage, low noise, high common mode rejection ratio, high power supply rejection ratio, micro-power consumption and the like; the circuit is particularly suitable for a wearable health monitoring system biopotential acquisition circuit adopting dry electrodes, and can eliminate semi-potential imbalance between electrodes in a rail-to-rail mode. The simulation result of one embodiment of the invention shows that the common-mode rejection ratio of the instrument amplifier is greater than 120 dB, the equivalent input impedance is greater than 500 M Ohm, and the noise energy efficiency factor NEF is equal to 4.5.

The invention discloses a signal conditioning circuit for detecting the thickness of a yarn. The signal conditioning circuit for detecting the thickness of the yarn is poor in self adaptation to different yarns at present. The signal conditioning circuit comprises a numerical control potentiometer control circuit, a direct current zero setting circuit and an instrument amplifier circuit. The numerical control potentiometer control circuit comprises a single chip microcomputer and a numerical control potentiometer, the direct current zero setting circuit comprises a single chip microcomputer, a resistor and a capacitor, and the instrument amplifier circuit comprises three operational amplifiers and seven resistors. The signal conditioning circuit conducts RC filtering on pulse-width modulation (PWM) signals output by the single chip microcomputers, then the PWM signals and signals output by an infrared receiving tube serve as a pair of difference signals to be input in the instrument amplifier circuit with controllable gain, and accordingly the signal conditioning circuit is guaranteed to have intelligent zero setting and an automatic gain adjusting function.

The invention relates to an online testing system for electrical parameters of a photoelectric coupler in a remote transmission mode, and relates to the technical field of aerospace electronics measurement. The system comprises a testing board, a data collector, a power source and an upper computer. The data collector comprises a signal conditioning circuit, a current-voltage converting circuit, an instrument amplifier, an analog-digital converter and an MCU. According to the system, the remote high-precision testing (within 20 m) of the space radiation sensitive parameter current transfer ratio (CTR), the on-state collector current (IC(on)), the on-state collector-base current (IR), the leakage current (IC(off)) and the saturation voltage drop (VCE(SAT)) of the photoelectric coupler is achieved. The invention further relates to an online testing method for the photoelectric coupler.

The invention relates to a chopping stable instrument amplifier, comprising a low-gain high-frequency closed circuit, a high-gain low-frequency closed circuit, and a residual RRL (Ripple Reduction Loop); wherein the low-gain high-frequency closed circuit consists of an operational amplifier Gm3 and an operational amplifier Gm4; the high-gain low-frequency closed circuit consists of a chopper CH1,an operational amplifier Gm1, a chopper CH2, an operational amplifier Gm2, a switched capacitor notch filter NOTCH and the operational amplifier Gm4; and the residual RRL consists of induction capacitors C41 and C42, a cascode buffer Cascade Buffer 1, a chopper CH3, a cascade buffer Cascade Buffer 2, an integrating capacitor Cint, and an operational amplifier Gm5. The chopping stable instrument amplifier of the invention has the beneficial effects that: through the low-gain high-frequency closed circuit and the high-gain low-frequency closed circuit, offset voltage and 1 / f noise of a circuit can be effectively eliminated, and bandwidth of the circuit can be greatly raised, on that basis the RRL is introduced to effectively reduce the amplitude of the ripple output by the circuit, thus thewhole circuit noise is optimized, low-noise output is achieved, thereby improving circuit accuracy.

The invention discloses a current sensor capacitance measurement circuit which comprises a first switch, a second switch, a first capacitor, a charge amplification circuit, a first sampling retainer, a second sampling retainer and an instrument amplifier. The charge amplification circuit comprises a first operational amplifier, a second capacitor and a third switch. The first switch and the second switch are in parallel connection at a left side terminal of the first capacitor. The first sampling retainer and the second sampling retainer are in parallel connection, one end of the two retainers is connected with the charge amplification circuit, and the other end of the two retainers is connected with the instrument amplifier. Control sequences of the first switch, the second switch and the third switch are different. Through the above mode, data acquisition speed of a data acquisition system can be greatly raised, influence of a charge injection effect of an electronic switch on measurement precision is solved well, and the current sensor capacitance measurement circuit has the advantages of high resolution, simple circuit structure and low cost.

A high frequency broadband amplifier used for piezoresistive dynamic pressure sensor, connected between outlet line of dynamic pressure sensor, including two-stage amplifiers, power filter circuit and signal filter circuit, the first-class amplifier was composed of the instrument amplifier, its input and negative feedback ends connect the two differential output end of the sensor; the second-class amplifier was composed of high-speed operational amplifier, its input end connect the output end of the instrument amplifier; the power filter circuit were positive or negative, individually parallel connect two electrolytic capacitors or two ceramic capacitors with the earth; the signal filter circuit was self-made band-pass filter consisted by three Y connected inductions, one induction concatenate the high-frequency ceramic capacitor, then connect with the outlet end of the operational amplifier, the other one parallel connect the high-frequency ceramic capacitor, then connect the earth; the last one was took as the outlet end of the amplifier after first connected in series the high-frequency ceramic capacitor. This invention is of high frequency, low noise, with fast rise speed, and anti-interference.

The invention provides a bridge type resistor strain sensor multi-mode fault detection device; under a broken line open circuit fault or a lead wire short circuit fault or a combined fault mode, a bridge type resistor strain sensor output line is pre-biased through a bias circuit; a high frequency signal is filtered by a radio frequency noise suicide circuit; the bridge type resistor strain sensor output line enters an instrument amplification circuit; the instrument amplification circuit amplifies a difference signal outputted by the bridge type resistor strain sensor; the amplified difference signal is compared with a reference voltage, set by a fault discrimination reference voltage set circuit, in a level comparison circuit, thus determining various fault modes of the bridge type resistor strain sensor; logic integration is finally realized by the line and circuit so as to output a logic signal, thus determining whether the bridge type resistor strain sensor has fault or not. The bridge type resistor strain sensor multi-mode fault detection device needs less parts, is easy to buy, low in cost, thus realizing various functions of the instrument amplifier, and effectively reducing PCB area and cost.

The invention relates to a dynamic signal acquisition processing device, comprising a sensor, a dynamic signal acquisition instrument and a computer; in the dynamic signal acquisition instrument, an instrument amplifier is connected with an A / D converter which is connected with a singlechip; the sensor is connected with the instrument amplifier, and the computer is connected with the singlechip; the sensor is a differential resistance type sensor, and a power supply circuit of the sensor is a constant flow source circuit. Aiming at the dynamic signal acquisition of the differential resistance type sensor which is commonly used in engineering safety monitoring mainly, the special dynamic signal acquisition processing device is designed, the dynamic sampling frequency of the dynamic signal acquisition processing device is 10Hz to 200Hz and can be set within the range of the measuring range according to needs, and the dynamic signal acquisition processing device is convenient for carrying and can carry out real-time sampling to the signal of the sensor, the sampling solution and precision are high, and the device can automatically process and store mass data.

The invention discloses a portable electroencephalogram collection system which comprises a collection electrode and a signal processing system. The signal processing system comprises a microcontroller, an input filter, a static protection unit, an instrument amplifier, an analog-digital converter, a storage module, a radio frequency transceiver, a power source management system and a display operation module, the power source management system comprises a power source module, a program storage unit and an induction eddy current charging circuit, and a display input module comprises a state display lamp and a button configuration unit. Electrodes are placed at foreheads of Fp1, FpZ and Fp2, and interference caused by hair is avoided, so that medical pasted wet electrodes are used, and interference of electrode contact impedance is avoided. A low-power-consumption device is adopted mainly, and the power source management system is arranged, so that state of a power source can be monitored, noise can be removed effectively, and elimination of electro-oculogram noise is based on an improved algorithm of discrete wavelet transformation and self-adaptive noise offset.

A sensor signal conditioner for temperature compensating, linearizing, and amplifying sensor signal output in electronic instrumentation circuits includes a programmable gain instrument amplifier having an input connected to a sensor; and a comparator for comparing an output voltage of the amplifier to a desired output voltage value. A micro-controller controls the instrument amplifier gain and offset. A mode switch converts an I / O pin to input the desired output voltage value in programming mode and connects the I / O pin to the amplifier output in user mode. A memory stores a programming protocol in the sensor signal conditioner so that in programming mode, the protocol stores programmed values and linearly fits the programmed values to set trim values for temperature compensating, linearizing, and amplifying the instrument amplifier output. The I / O pins and mode switches of several sensor signal conditioners can be controlled simultaneously to mass produce transducers using the sensor signal conditioner.

The invention relates to a device for rapidly and nondestructively detecting the component content of yellow rice wine. The existing detection method has the disadvantages of large time consumption, complication in operation and damage to a sample. In the device provided by the invention, after the light emitted by a light source is collimated through a lens, a modulating disk is aligned to the collimated parallel light, thereby carrying out the light intensity modulation; the collimated parallel light is split by a spectrometer which comprises an interference filter, a filter wheel and a stepper motor; the monochromatic light with the bandwidth of 10-20nm is emitted into an immersion optical fiber probe and then emitted to a detector; after the weak photoelectric signals output by the detector are amplified by an instrument amplifier and processed through a low pass filter, and the weak photoelectric signals are converted into digital signals by a converter; and the digital signals are transmitted to a digital signal processor. The device provided by the invention can be used for carrying out the nondestructive detection on conventional detection items such as the alcohol, sugar and acidity and the like in the yellow rice wine, is rapider and more friendly-environment than the conventional yellow rice wine component physicochemical check, does not need to preprocess the sample and has the advantages of good detection result repeatability and low detection cost.

The invention provides a device for carrying out spectrum measurement on a vibration object by utilizing the laser triangle vibration measurement technology. The measurement mode belongs to the long-distance non-contact measurement mode and is characterized by high precision, high interference resistance and extending stability. The object vibration spectrum measurement system based on the laser mainly comprises a signal acquiring part, a signal processing part and a spectrum analyzing part; the signal acquiring part has the operating principle that a stable focusable laser generator is adopted for generating the laser, and the laser is irradiated on a vibration object to be measured; two photoelectric cell sensors are arranged at 45 degrees from each other and are used for receiving the reflected laser with the object vibration information, as well as implementing photovoltaic conversion; the signal processing part has the operating principle that an AD620 precision instrument amplifier, an NE5532 optional amplifier and a Cortex-M4 single chip microcomputer are adopted for carrying out differential amplification, filter and amplification and AD sampling and storing on the converted electric signal; and the spectrum analysis part has the operating principle that the Cortex-M4 single chip microcomputer is utilized for carrying out FFT (Fast Fourier Transform Algorithm) on the sampled signal so as to obtain a frequency domain signal, and displaying the frequency domain distribution data in a graphic form by utilizing a display. By adopting the object vibration spectrum measurement system based on the laser, a user can conveniently see the vibration information of the measured object.

The invention discloses an apparatus for measuring the height of an aircraft, and a method thereof. The apparatus includes a baroceptor, an instrument amplifier, a digital-to-analog conversion circuit, a filter circuit, a microprocessor and a power module; instrument amplifier is connected to the output end of the baroceptor, the filter circuit is connected to the output end of the baroceptor, and the baroceptor acquires change information of the pressure with the height and outputs a first voltage; the first voltage is amplified by the instrument amplifier, the amplified first voltage is filtered by the filter circuit, and the filtered amplified first voltage is output; the digital-to-analog conversion circuit converts a digital voltage value corresponding to the current pressure plane height of the aircraft to a reference voltage; the instrument amplifier amplifies a difference between the first voltage and the reference voltage and then outputs a second voltage; and the microprocessor processes the filtered first voltage and the filtered second voltage, and then outputs the current height of the aircraft. The apparatus and the method have the advantages of reduction of the height measurement cost of a missile flight control process,, improvement of the height measuring resolution and accuracy, simple circuit and low power consumption.

The invention provides a sensor used for magnetic conductivity measurement. The sensor comprises a four-tap solenoid coil. Four taps are led out of the solenoid coil from the top to the bottom in turn. The first tap of the four taps is connected with an excitation current source which is connected with the ground. The fourth tap is connected with the ground potential of the excitation current source so as to form a current loop. The second tap and the third tap are connected with the input end of an instrument amplifier to acquire differential voltage and connected with a voltage measurement module. The invention also provides a measurement method using the sensor used for magnetic conductivity measurement. The effects of the sensor used for magnetic conductivity measurement are that the four-tap solenoid sensor is simple and feasible and can directly measure the magnetic conductivity of particle / powder material without preparing a magnetic core of the specific shape in advance; the physical model of the sensor is clear, and the relational expression between the induction value and the measured medium magnetic conductivity can be determined by the analytic formula so that structural optimization and parameter correction are facilitated; and the middle tap performs measurement so that the influence of the edge effect of the two ends of the solenoid can be avoided and the more accurate measurement result can be acquired.