1652 results about "Signal processing circuits" patented technology

The invention discloses a high-speed multi-photon detection system and method. The system comprises a detector and a signal processing circuit, wherein the detector is composed of a window plated with a photoelectric cathode, a micro-channel plate stack and an anode; a plurality of incident photons are converted into a plurality of photoelectrons by the photoelectric cathode, and the photoelectrons are converted into electron cloud by the micro-channel plate stack; the incident electron cloud is divided into multiple paths by three layers of staggered metal strip electrodes of the anode, and charge collection is carried out to obtain charge short pulses of each layer of electrode; the signal processing circuit converts the charge short pulses transmitted by the three layers of electrodes into digital pulse signals, obtains the centroid coordinates of the electron cloud from the digital pulse signals as the abscissa value, the ordinate value and the verification value of the incident photon position, combines the abscissa value, the ordinate value and the verification value based on the screening condition to obtain the target two-dimensional coordinates, and finally obtains the target two-dimensional coordinates. And transmitting to a terminal for imaging display. According to the invention, a plurality of synchronous photons can be detected, the overall counting rate of the detector is greatly improved, and the detection efficiency is improved.

A system and method for detecting anomalies in encrypted network traffic without decrypting encrypted payloads is disclosed. The invention comprises a hardware-accelerated pipeline including a packet acquisition unit configured to extract observable header attributes and timestamp values, a signal analysis unit implemented using digital signal processing circuitry to generate temporal and spectral characteristics of encrypted packet flows, and a morphometric extraction unit that produces encrypted-flow descriptors based on statistical dispersion, burst patterns, and ciphertext variability. A behavioral graph construction unit generates graph-structured representations of encrypted flows using incremental state-transition encoding. An artificial-intelligence inference unit employing a tensor-processing processor performs multi-stage anomaly analysis through temporal reconstruction, attention-based weighting of descriptors, and graph-structural deviation assessment to compute anomaly scores without decrypting any payload. A secure response control unit evaluates the scores against policy thresholds and performs mitigation actions while preserving confidentiality.

The invention discloses an electricity testing measuring device for power equipment. The invention relates to the field of space electric field measurement, and solves the problems of unsafety and low anti-interference capability of an existing electricity testing scheme. The electric field sensor collects the electric field intensity in a non-contact manner, and the distance sensor synchronously collects the detection distance, so that a conventional contact type electroscope does not need to contact equipment through a telescopic insulating rod. The signal processing circuit preprocesses electric field intensity information and distance information respectively to obtain effective analog signals representing the electric field to be measured, and the defect that a traditional non-contact plate electrode sensor induces stray electric fields indifferentially is overcome. Besides, the judgment control circuit judges the electrification state according to the preset electric field threshold value corresponding to the current distance analog signal instead of a single fixed threshold value of a traditional device instead of adopting a fixed threshold value, the electric field distribution characteristics of equipment with different voltage grades are adapted, manual intervention is not needed, and personal safety is guaranteed. And the occurrence rate of production accidents caused by abnormal electrification of equipment is reduced.

The invention relates to the technical field of power distribution automation auxiliary power supply control, and discloses an intelligent power distribution circuit system for a digital ring main unit, which comprises a transient voltage gradient induction bridge circuit, a hardware signal processing circuit, a power switch unit and a controlled energy release unit, according to the system, a transient voltage gradient induction bridge circuit is used for collecting a primary side bus voltage change rate signal, a hardware signal processing circuit carries out derivation operation on an induction signal and compares the induction signal with a voltage gradient threshold value, and a power switch unit is blocked at the moment that the voltage abnormally drops so as to cut off a load current path. According to the invention, a hardware parameter direct mapping mechanism is utilized to realize microsecond transient protection response, and the physical decoupling of protection logic and digital software is realized by balancing bus potential pulse caused by sudden unloading of a load through the inherent dehumidification resistor in the multiplexing cabinet.

The invention discloses a radio frequency voltage sensor and a plasma source system. The radio frequency voltage sensor comprises a signal acquisition module and a signal processing circuit. The signal processing circuit comprises a rectangular wave pulse detection module, a signal conversion module, a peak holding module and an operation output module; the input end of the rectangular wave pulse detection module receives a pulse synchronization signal; the signal conversion module is connected with the output end of the signal acquisition module; the first input end of the peak holding module is connected with the output end of the signal conversion module, and the second input end of the peak holding module is connected with the output end of the rectangular wave pulse detection module; and the operation output module is connected with the output end of the peak holding module. According to the radio frequency voltage sensor and the plasma source system provided by the invention, the peak voltage corresponding to the single-stage pulse can be accurately detected, the peak voltage corresponding to the multi-stage pulse can also be stably detected, the output is prevented from jumping to zero during the pulse closing period, and the stability and practicability of measurement are improved.

The invention discloses a Rogowski coil current transformer and a current measurement system, and relates to the technical field of current measurement. The Rogowski coil current transformer comprises a Rogowski coil and a signal processing circuit; the differential signal is converted into a differential constant-current signal to be output based on a signal processing circuit; the signal processing circuit comprises an integral amplification module for performing integral amplification on the differential signal based on the integral amplification module; the first direct current component removing module is used for removing a direct current component in the voltage signal after integral amplification based on the first direct current component removing module; the signal adjusting module is used for realizing amplitude in-phase amplification and phase compensation; the single-ended to differential output module is used for generating symmetrical differential voltage signals based on the single-ended to differential output module; and the conversion module is used for converting the symmetrical differential voltage signal into a differential constant current signal and outputting the differential constant current signal based on the conversion module. And through the integral amplification module and the phase compensation module, the differential signal is accurately converted into the current signal, so that the current measurement result is more accurate.

The utility model provides a multichannel staggered sampling SPAD module which is arranged in a laser radar and serves as a receiving module of a machine radar, an MCU is arranged in a laser tool, the MCU is provided with an MCU interface, and the multichannel staggered sampling SPAD module comprises an SPAD unit, a TDC circuit array, a signal processing circuit and a coding circuit; wherein the work cycles of the TDC circuits in the TDC circuit array are sequentially arranged in a staggered manner, so that time of the SPAD units is sampled in a staggered manner, a delay chain is formed, the TDC circuit array can output a second value once every a fixed time length, and the fixed time length is smaller than the work cycle of one TDC circuit. After the technical scheme is adopted, the upper limit of the signal transmission rate can be greatly improved, so that the sampling efficiency is improved, and stronger scanning performance is realized.

An inertial measurement device includes: an inertial sensor; a first signal processing circuit; a second signal processing circuit; a first communication unit and a second communication unit configured to communicate with an external device; and a mode selection unit configured to select a processing mode from a plurality of modes including a first processing mode and a second processing mode. The first processing mode is a mode in which the inertial measurement device is used alone and outputs a signal processed by the first signal processing circuit from the first communication unit, and the second processing mode is a mode in which the inertial measurement device is used in a state of being coupled to another inertial measurement device, a first signal processed by the first signal processing circuit and a second signal from another inertial measurement device received from the second communication unit are subjected to a calculation process by the second signal processing circuit, and a signal subjected to the calculation process is output from the first communication unit.

The invention relates to a preparation method of a surface acoustic wave filter integrated with a CMOS (Complementary Metal Oxide Semiconductor) process, which comprises the following steps of: preparing a CMOS radio-frequency signal processing circuit by using a silicon or silicon carbide substrate, combining a dielectric buffer layer with a piezoelectric material, and then depositing a metal interdigital structure on the surface of the piezoelectric material to prepare the surface acoustic wave filter. A passivation layer is deposited on the surface of the filter to protect the filter structure, finally a metal interconnection line and the passivation layer are prepared above the filter, and in order to not affect the performance of the filter, an air cavity is prepared between the passivation layer and the metal interconnection layer of the filter, so that the passivation layer and the metal interconnection layer are effectively isolated. According to the preparation method, the surface acoustic wave filter and the CMOS radio frequency circuit can be integrated, the problem that radio frequency front-end and rear-end signal processing cannot be integrated at the same time at present is solved, and the preparation method plays an important role in promoting development of a radio frequency chip in the directions of high integration, low cost, miniaturization and the like; and the radio frequency chip has wide practical value and economic value in the radio frequency chip application field.

The invention discloses a peak code modulation circuit based on a dynamic memristor, which comprises the dynamic memristor and a signal conversion module, and is characterized in that the signal conversion module comprises a signal isolation module, a feature extraction module and a pulse conversion module which are connected in sequence. The dynamic memristor generates a voltage signal with a slow-rising and steep-falling characteristic under constant current input. The signal isolation module comprises a high-impedance input buffer circuit; the feature extraction module comprises an asymmetric time constant signal processing circuit used for performing enhanced extraction on the steep drop feature of the memristor output signal; and the pulse conversion module comprises a dual-threshold positive feedback hysteresis comparison circuit and is used for converting the output signal of the feature extraction module into a rectangular digital pulse. The circuit is specially designed according to the characteristics of the memristor, is simple in structure, is easy to integrate, can achieve the efficient conversion from an analog signal to a standard digital pulse, and is suitable for the fields of neuromorphic calculation and low-power-consumption signal processing.

The invention relates to the technical field of automatic welding, and discloses a micro welding seam tracking method and system based on electromagnetic induction. According to the method, a high-frequency alternating magnetic field is applied to a welding seam area through an exciting coil in the micro electromagnetic sensing core; an induction coil in the electromagnetic sensing core is used for detecting magnetic field disturbance caused by geometric shape changes of the weld groove, and induction signals are obtained; processing the induction signal through a signal processing circuit integrated in the probe, namely converting the impedance change of the coil into a voltage signal, demodulating and filtering the voltage signal, and extracting a direct-current voltage signal corresponding to the deviation of the probe relative to the central position of the welding seam; the direct-current voltage signals serve as position feedback information to be output to a welding robot control system; and the movement track of the welding robot is adjusted in real time according to the position feedback information, and welding seam tracking and path deviation correction are achieved.

A system and method are described for emitter identification and tracking in an electronic warfare (EW) environment. The system includes an antenna array configured to receive signals from radio frequency (RF) emitters during a dwell. Processing circuitry converts the received signals into digital signals. Pulses are detected and characteristics of the pulses determined to form pulse descriptor words (PDWs). The PDWs obtained during the dwell are deinterleaved using unsupervised machine learning to form clusters. The clusters are categorized using one or more supervised machine learning algorithms to determine whether the PDWs correspond to known or unknown emitters and the results tracked as in or out of library emitters. After merging the in or out of library emitters, an emitter report is generated and used to update a library of emitter profiles used by the supervised machine learning algorithms as well as determine countermeasures to generate.

A measurement system includes a common port, the common port being connectable to a signal output of the device under test. The measurement system further includes a signal line being connected to the common port, wherein the signal line includes a first directional coupler portion and a second directional coupler portion. The measurement system further includes a signal processing circuit, wherein the signal processing circuit includes an IQ analysis circuit and an IQ synthesizer circuit. The IQ analysis circuit is connected with the common port via the first directional coupler portion so as to receive a forward-travelling signal from the common port. Further, a testing method of testing a device under test is described.

The invention discloses a firework and firecracker setting-off control system and method based on geo-fencing and optical communication, and belongs to the technical field of fireworks and firecrackers, and the system comprises a mobile terminal, a firework and firecracker terminal and a cloud server; the cloud server constructs a geofence database, a product filing database and a product key library; the firework and firecracker terminal comprises a firecracker body, an electronic fuze module used for igniting the firecracker body, a firecracker terminal optical communication module used for receiving an ignition signal, and a signal processing circuit used for processing the ignition signal and controlling the electronic fuze module to start. The mobile terminal is at least provided with a satellite positioning module used for determining real-time geographic coordinates of the mobile terminal and an image acquisition module used for shooting terminal information images of fireworks and crackers to be set off; according to the method, safe setting-off and supervision of fireworks and crackers are guaranteed through satellite positioning, optical communication technologies and image recognition technologies, and the method is particularly suitable for supervision scenes in which the government defines combustion prohibited areas.

The invention provides a triaxial accelerometer based on a four-degree-of-freedom weak coupling resonator, the triaxial accelerometer comprises an upper-layer structure and a lower-layer structure, the upper layer is a micromechanical sensitive element constructed by taking silicon as a material, the lower layer is a glass base processed by a silicon dioxide material, and the glass base is used for providing mechanical support and electrical isolation functions. Wherein the micromechanical sensitive element has a signal conversion function; and the lower-layer glass base is formed by wet etching and metal sputtering processes and is used for signal output. On the basis of collaborative design of the orthogonally distributed resonance unit array and the mechanical amplification mechanism, electrostatic driving and amplitude ratio detection are combined, synchronous and accurate sensing of acceleration of the Y axis, the X axis and the Z axis is achieved through a single sensitive element, the technical limitation of a traditional single-axis detection mode is broken through, the complexity of a rear-end signal processing circuit is reduced, and the detection precision is improved. The device space utilization rate is improved.

The invention belongs to the field of photoelectric detection imaging, and provides a photoelectric detection imaging integrated chip and a use method thereof, and the chip comprises a visible light miniature light-emitting diode array and a photoelectric detector array which are connected with each other in a one-to-one correspondence manner. Photoelectric detection imaging is completed through direct conversion of the detection target optical signal and the visible light imaging signal between the pixels, and the frame rate of the photoelectric detection imaging system is greatly improved; a reading circuit, a signal processing circuit and an imaging system in a traditional photoelectric detection imaging system are replaced by the miniature light-emitting diode display array, the power consumption of the photoelectric detection imaging system is effectively reduced, the imaging resolution and the display effect of the photoelectric detection imaging system are improved, and miniaturization and portability of the photoelectric detection imaging system are facilitated.

The utility model discloses a current metering circuit for a protection board, which comprises a charging and discharging protection circuit, a current acquisition circuit and a controller circuit, and is characterized in that the charging and discharging protection circuit is used for carrying out charging and discharging protection control on a battery; the current acquisition circuit comprises a current sampling resistor R39 and a current signal processing circuit, the current sampling resistor R39 is used for sampling current, and a signal input end of the current signal processing circuit is connected with the current sampling resistor R39 so as to output the sampled current after processing the sampled current; and the controller circuit carries out overcurrent protection control and / or carries out flow statistics output on the current through the charging and discharging protection circuit according to the sampling current. Therefore, a special metering chip is replaced by the independent current signal processing circuit and the controller circuit, so that the implementation of the whole metering function is cheaper, the controller circuit can transmit current metering signals to the outside in a wired or wireless mode, and the application is more flexible.

The invention discloses a multi-mode sensing manipulator system based on flexible electronic skin, an integration process and a test method, and the multi-mode sensing manipulator system based on the flexible electronic skin comprises a flexible electronic skin sensor attached to a manipulator; the flexible electronic skin sensor comprises a flexible sheet and a liquid alloy network arranged in the flexible sheet, the liquid alloy network comprises an SSPP structure and a piezoresistive sensing structure located on the periphery of the SSPP structure, and the SSPP is a simulated surface plasmon; the piezoresistive sensing structure is connected with the signal processing circuit through a flexible wire bar and transmits a piezoresistive signal to the processor; the SSPP structure is connected with the SDR module through a coaxial line and is connected with the processor. According to the multi-mode sensing manipulator system based on the flexible electronic skin, the integration process and the testing method, the functions of multi-dimensional force feedback, substance penetrating type sensing and dynamic curved surface adaptation are achieved.

The invention belongs to the technical field of nondestructive detection defect evaluation, and particularly relates to an electromagnetic regulation and control detection method and system for structural defects of offshore oil well control equipment. According to the electromagnetic regulation and control detection method and detection system for the structural defects of the offshore oil well control equipment, crack multi-feature signals are obtained through amplitude-frequency phase regulation and control of electromagnetic excitation signals, angle information of cracks is obtained by means of a residual network, and accurate identification of crack length and depth information is achieved; and the service life prediction network realizes effective prediction of the residual fatigue life. The detection system comprises a monitoring probe, an excitation signal generation unit and a monitoring signal processing and collecting unit, the monitoring probe consists of an exciting coil group, an array sensor and a front-end signal processing circuit; the excitation signal generation unit comprises a signal generator and a power amplifier; the monitoring signal processing and collecting unit comprises a multiplexing and amplifying filter circuit, a band-pass filter circuit, a phase-locked amplifying circuit and a signal collecting board card.

Aspects of the disclosure provide methods and apparatuses for video encoding / decoding. In some examples, an apparatus for video decoding includes receiving circuitry and processing circuitry. The processing circuitry extracts, from a bitstream, a signal indicative of an application of a template matching based block vector refinement for coding a current block in a current picture referencing (CPR) mode. The processing circuitry derives a first refined block vector associated with the current block according to the template matching based block vector refinement. The first refined block vector includes a first block vector refinement offset applied on a first block vector associated with the current block. The processing circuitry reconstructs the current block according to a first reference block in a same picture as the current block, the first reference block being indicated by the first refined block vector.

The invention discloses an embedded domestic signal processing board, which relates to the technical field of signal processing circuits and comprises a power supply management module used for filtering ship electric interference through transient voltage suppression and digital ground and analog ground physical isolation and providing multi-path voltage stabilization output for wide voltage conversion; the intelligent control module is used for executing double-CAN channel dynamic switching based on physical layer monitoring and multi-mode fusion relay life prediction, and communication redundancy management and intelligent early warning are achieved; the signal processing module is used for executing high-precision current acquisition by adopting a temperature dynamic compensation algorithm and realizing pulse interference harmonic identification through real-time spectrum analysis; and the driving execution module is used for driving and controlling multiple paths of equipment through time division multiplexing and generating hierarchical light coding indication in combination with the life early warning model. According to the invention, 100% homemade replacement of ship key equipment is realized through full-link autonomous design, the reliability of the system is remarkably improved, and communication redundancy guarantee and accurate early warning of the equipment state are realized.

The invention discloses a gradient thermocouple liquid level real-time detector, and relates to the technical field of liquid level detection, an integrated gradient thermocouple probe rod structure is adopted, a plurality of groups of thermocouple nodes are integrated on a single corrosion-resistant alloy integrated gradient thermocouple probe rod according to a preset interval through a special process, and a continuous temperature gradient sensitive area is formed. A high-precision signal processing circuit is embedded in the integrated gradient thermocouple probe rod, the temperature difference potential of each node is collected in real time, the liquid level height is calculated based on a dynamic temperature field modeling algorithm, and full-scale continuous measurement is achieved. Gradient node distributed layout is created for the first time, and a blind area of traditional point type measurement is eliminated; a self-adaptive temperature compensation mechanism is developed, and medium layering and boiling interference are overcome; the integrated gradient thermocouple probe rod adopts vacuum sealing and a nanometer heat insulation coating, and can resist a high temperature of 600 DEG C and a high pressure environment of 40 MPa. The device has millimeter-level measurement precision and millisecond-level dynamic response capability, does not need to move parts or external radiation sources, and remarkably improves the reliability, safety and installation convenience of liquid level monitoring of industrial reaction kettles and high-pressure boilers under extreme working conditions.

The utility model discloses a current sampling system and an energy storage device. The current sampling system comprises a control unit, a plurality of current sampling circuits and a plurality of signal processing circuits, wherein each current sampling circuit is provided with a sampling resistor and a switching device; a connecting end after the first ends of the current sampling circuits are connected is connected with the negative electrode end of the storage battery, and a connecting end after the second ends of the current sampling circuits are connected is connected with an external power device; the signal receiving end of each signal processing circuit is connected with the sampling resistor in the current sampling circuit corresponding to the signal processing circuit, and is used for collecting differential voltage at the two ends of the sampling resistor and sending the differential voltage to the control unit; the control unit is used for receiving the differential voltage and determining the battery current of the storage battery based on the differential voltage. According to the technical scheme disclosed by the utility model, the sampling precision of the battery current of the storage battery can be improved.

The invention relates to a neural network-based high-voltage live-line work safety early warning method. The method comprises the following steps of 1, establishing a high-voltage transmission line electric field calculation model by using a surface charge method; 2, establishing an overall three-dimensional model of the transformer substation; 3, constructing a signal processing circuit of the power frequency electric field sensor, capturing electric field information in real time through the power frequency electric field sensor, and converting the electric field information into a processable electric signal; 4, real-time data from the power frequency electric field sensor are received, feature extraction and classification are carried out by adopting an early warning method based on a convolutional neural network, and potential safety hazards are identified; 5, establishing a neural network-based high-voltage live working safety early warning comprehensive platform integrating data acquisition, processing, analysis and early warning; the method has the advantages that the neural network algorithm is adopted, the distance and the azimuth angle are accurately judged, live-line work is early warned, and the accident rate is greatly reduced.

The embodiment of the invention provides a signal processing circuit and an integrated circuit. The signal processing circuit includes: a first amplification branch including a first operational amplifier and a first resistance network connected to the first operational amplifier; a detection branch coupled to an input of the first amplification branch, the detection branch comprising a variable resistor and configured to detect a common mode component input to the first amplification branch and generate a compensation signal based on the common mode component and a resistance value of the variable resistor; and an adjustment branch coupled between the detection branch and the first amplification branch and configured to adjust the compensation signal and apply the adjusted signal to the first amplification branch to reduce an input deviation of the first operational amplifier, the input deviation being associated with a resistance mismatch and a common mode component of the first resistance network.

The invention relates to the related technical field of geophysical exploration instruments, in particular to a miniaturized broadband induction type magnetic field sensor. The sensor comprises a magnetic core, an induction coil, a feedback coil and a signal processing circuit. The invention is characterized in that the magnetic core is of a long rod-shaped structure formed by laminating and curing high-permeability soft magnetic strip materials, the length of the magnetic core is 580mm-640mm, the cross section of the magnetic core is a square or an equivalent circle with the side length of 11mm-15mm, and the length-diameter ratio of the magnetic core is greater than 40; the feedback coil is formed by spirally winding a metal foil belt along the magnetic core, and the metal foil belt forms a main shielding layer for restraining interference of an external electric field at the same time. By optimizing the size and the length-diameter ratio of the magnetic core and combining the integrated design of feedback and shielding functions, while the working frequency band and the low-noise performance are ensured, remarkable miniaturization and light weight of the sensor are realized, and the portability and the layout efficiency of field exploration are greatly improved.

The invention belongs to the technical field of optical gas sensing, and provides an optical fiber microcavity gas sensing system and method based on photoacoustic excitation and detection enhancement. The sensing system comprises a narrow linewidth laser light source, a wide-spectrum detection light source, a wavelength division multiplexer, an optical circulator, a high-speed spectrometer, a signal processing circuit, a single-mode optical fiber and an embedded single-optical-fiber photoacoustic sensing probe. The novel structure is characterized in that the partially gold-plated optical fiber is embedded into the gold-plated opto-acoustic micro-cavity to form a miniature optical'cage ', so that multiple reflections of light in a free space are realized. In addition, in order to make full use of the high sensitivity of the silicon cantilever beam in photoacoustic detection, the structural design of the embedded single optical fiber for expanding the inner cavity reduces the pressed film damping of the silicon cantilever beam during resonance. According to the embedded single-optical-fiber photoacoustic sensor, the multi-pass photoacoustic microcavity and the ultra-sensitive optical fiber microphone are applied, so that double enhancement of photoacoustic excitation and detection is realized, and the gas detection precision is improved.

A digital surface position sensor includes a position sensor, an adaptable hardware interface, and a processing circuit. The position sensor is adapted to be coupled to an aircraft flight control surface and is configured to sense a position of the aircraft flight control surface and supply a position signal representative thereof. The adaptable hardware input supplies an identification signal that identifies the aircraft flight control surface to which the position sensor is coupled. The processing circuit is coupled to receive the position signal and the identification signal. The processing circuit is configured, upon receipt of the signals, to process the position signal and the identification signal and generate (i) a first digital position signal representative of the position of, and the identification of, the aircraft flight control surface and (ii) and independent second digital signal representative of the position of, and the identification of, the aircraft flight control surface.

The invention provides a high-integration-level signal reading module for a neutron proportional counter tube, and belongs to the technical field of neutron detection, the high-integration-level signal reading module comprises stacked double-layer circuit boards, and the upper circuit board and the lower circuit board are connected through pin interfaces; the upper circuit board is provided with a signal processing circuit which is used for reading, amplifying, discriminating and shaping signals of the neutron proportional counter tube. The lower-layer circuit board is provided with a positive and negative dual-power-supply support circuit which provides + / -3.3 V power supply support for the signal processing circuit of the upper-layer circuit board. The module supplies power through the lower-layer power panel, and the lower-layer circuit board supplies positive and negative power to the upper-layer circuit board after completing power conversion. Signals are input through the IPX interface of the upper-layer circuit board and are output through the other IPX interface after being processed. The charge sensitive pre-amplifier, the broadband voltage amplifier, the pulse discriminator circuit, the pulse shaping circuit and the power management module are integrated in the same module, so that the real integrated design is realized.

A signal processing circuit for a tunneling magnetoresistance sensor comprises thirty-eight MOS transistors, two capacitors and ten switches. A first switch, a second switch, a third switch, a fourth switch, a first MOS transistor, a second MOS transistor, a third MOS transistor and a fourth MOS transistor form a high-frequency modulation circuit. A fifth switch, a sixth switch, a seventh switch, an eighth switch, a seventeenth transistor, a twenty-second MOS transistor and a twenty-third MOS transistor form a high-frequency demodulation circuit. A signal output by a tunneling magnetoresistance sensor is modulated to a chopping frequency by the high-frequency modulation circuit, and is then demodulated by the high-frequency demodulation circuit.