270 results about "Instrument amplifier" patented technology

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 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 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 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 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.

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 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.

An instrument amplification system provides improved low frequency enhancement. A powered subwoofer system enhances the low frequency components of a standard instrument amplifier by incorporating a speaker level high-pass filter crossover network prior to connection to a standard instrument speaker. The speaker level instrument amplifier output is also attenuated, low-pass filtered and re-amplified to drive a dedicated low frequency subwoofer speaker. In one embodiment, a single speaker cabinet connects via a single speaker cable and includes both typical instrument speakers and an active powered subwoofer system. In another embodiment, a stand alone active powered subwoofer connects to a standard instrument amplifier and includes a speaker level high-pass crossover output for connection to a standard instrument speaker cabinet. The instrument amplifier speaker output is attenuated, low-pass filtered, re-amplified and connected to a low frequency subwoofer speaker. A differential attenuator is incorporated allowing connection to instrument amplifiers with differential bridge outputs.

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.