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68 results about "Digital demodulation" patented technology

Detection method of ocean magnetic field sensor based on diamond NV color center

The invention discloses a detection method of an ocean magnetic field sensor based on a diamond NV color center. The detection method comprises the following steps: S1, calibrating a base line; s2, alternately measuring fluorescence between two single quantum resonance frequencies, and obtaining a difference to realize DQ reading; s3, three-axis compensation current is adjusted based on closed-loop control, and the NV working point is maintained at zero magnetization bias; s4, obtaining background magnetic field change through digital demodulation and adaptive filtering; and S5, calculating a gradient based on the spatial difference of the multi-point light spots, judging the existence and trajectory of the underwater vehicle in combination with a threshold value and a spectrum matching method, calibrating the threshold value according to the magnetic field characteristics of the existing underwater vehicle, adopting short-time Fourier transform signal spectrum, comparing the threshold value with known submarine characteristic spectrum data, and prompting if the similarity exceeds a set threshold value. According to the detection method, the measurement precision and the anti-interference capability can be improved, and the method is suitable for real-time monitoring of weak magnetic anomalies (such as magnetic moment disturbance of an underwater vehicle).
Owner:OCEANOGRAPHIC INSTR RES INST SHANDONG ACAD OF SCI

Digital demodulation method suitable for deep ultraviolet light communication

The invention relates to the technical field of digital demodulation, in particular to a digital demodulation method suitable for deep ultraviolet light communication, which comprises the following steps of: adopting multiple delay processing with half code element width, and respectively carrying out double extraction processing on a discrete sampling signal which is not subjected to delay processing and a plurality of delay sampling signals to obtain a plurality of delay extraction signals; in this way, the key sampling time in the coverage code element period can be ensured, and a basis is provided for subsequent accurate synchronization; a plurality of delay extraction signals are respectively input into corresponding equalization processing units, a preset local training sequence is loaded to each equalization processing unit to obtain a plurality of equalization filtering signals, and the plurality of equalization filtering signals and the preset local training sequence are respectively subjected to related judgment processing, so that the inter-symbol interference is inhibited, and meanwhile, the equalization processing efficiency is improved. The synchronization signal can be quickly screened out, so that the problem that inter-symbol interference and synchronization are difficult to consider in a traditional demodulation method is solved, and the demodulation efficiency and reliability are remarkably improved.
Owner:FUJIAN XINGHAI COMM TECH

Digital full even harmonic demodulation method based on full-phase analysis for magnetic modulator

This application relates to the field of electrical technologies, and provides a full even harmonic digital demodulation method based on full-phase analysis for a magnetic modulator. According to the full even harmonic digital demodulation method based on full-phase analysis for a magnetic modulator, standard voltage timing data output by the magnetic modulator is obtained when a DC calibration current with a set amplitude is fed into the magnetic modulator during calibration of the magnetic modulator; an output voltage sequence from full-phase Fourier analysis is established based on the standard voltage sequence data, and the output voltage sequence is preprocessed; comprehensive analysis is performed on the preprocessed output voltage sequence from full-phase Fourier analysis to obtain all standard even harmonic signals and current conversion coefficients.
Owner:LI XIAOLING +2

Common-mode interference resistant active pen and touch screen interaction system and signal demodulation method

The invention discloses an active pen and touch screen interaction system resistant to common-mode interference and a signal demodulation method. The system comprises a signal receiving terminal and a signal transmitting terminal. The signal transmitting terminal modulates data to be transmitted by adopting a differential binary phase shift keying modulation method, and transmits a generated modulation signal to the signal receiving terminal; the analog front-end receiving module is coupled with the signal transmitting terminal, receives the modulation signal and outputs a digital square wave signal after fidelity extraction processing; and the digital demodulation processing module performs differential coherent digital demodulation on the digital square wave signal based on the prior characteristics of the modulation signal, inhibits residual noise and recovers data to be sent. The analog front end focuses strong common-mode noise suppression and analog filtering, the digital demodulation algorithm performs secondary digital purification by using signal time sequence characteristics, and the two constructs an efficient anti-interference pipeline. Meanwhile, the regular square wave signals can be directly processed through differential coherent demodulation, and the requirements for performance and power consumption of a rear-end processor are lowered.
Owner:SHANGHAI HYNITRON TECH CO LTD

Intelligent adaptive underwater acoustic communication system

The invention relates to the technical field of self-learning underwater acoustic communication, and provides an intelligent self-adaptive underwater acoustic communication system. The multi-system transmitter comprises a data transmitting unit used for transmitting communication data, a system switching unit used for switching a transmitting signal modulation mode, and a transmitting signal modulation unit used for modulating a signal. The intelligent multi-system receiver comprises a synchronization unit, a Doppler estimation and compensation unit, an intelligent modulation mode identification unit, a data processing unit, an intelligent signal interpretation unit and a digital demodulation unit. Wherein the channel information identification unit is used for identifying the signal-to-noise ratio and the channel maximum time delay of an underwater acoustic channel and transmitting the signal-to-noise ratio and the channel maximum time delay to the system switching unit, and the system switching unit adjusts and switches a transmitting signal modulation mode according to the signal-to-noise ratio and the channel maximum time delay. The intelligent modulation mode identification unit employs a lightweight neural network to intelligently identify a signal modulation mode of an underwater acoustic channel signal, and the intelligent signal interpretation unit employs a deep learning neural network to intelligently interpret an underwater acoustic communication signal so as to recover communication data.
Owner:OCEAN UNIV OF CHINA

Long-distance optical fiber interference type sensing system based on synchronous differential closed-loop structure

The invention discloses a long-distance optical fiber interference type sensing system based on a synchronous differential closed-loop structure. The device comprises a light source module, a frequency modulation module, a long-distance transmission module, a reference light transmission module, a detection light transmission module, a reference light photoelectric conversion module, a sensing light photoelectric conversion module, an intermediate frequency mixing module, a zero intermediate frequency mixing module and a digital demodulation control module. According to the long-distance optical fiber interference type sensing system based on the synchronous differential closed-loop structure, in long-distance high-precision measurement, common-mode suppression of carrier phase noise is effectively achieved by introducing a synchronous signal pair and combining differential detection, and therefore the limitation of the carrier phase noise on improvement of the noise detection performance of the system is avoided.
Owner:ZHEJIANG UNIV

Resonant ring micro-electro-mechanical gyroscope time-sharing digital control system

The invention belongs to the field of closed-loop control of resonant ring micro-electro-mechanical gyroscopes, and particularly relates to a time-sharing digital control system of a resonant ring micro-electro-mechanical gyroscope. Comprising a resonant ring micro-electro-mechanical gyroscope, two modal driving / detection electrode time-sharing switching modules, two modal detection modules, two analog-to-digital converters, three digital-to-analog converters, three single-ended to differential driving modules and a digital processing unit, and the digital processing unit generates driving / detection time-sharing control signals S1 and S2. Performing digital demodulation, filtering, control resolving, direct digital frequency generation and modulation processing on the first modal detection signal to realize time-sharing stable tracking closed-loop control of the resonant frequency of the gyroscope and time-sharing stable closed-loop control of the vibration amplitude; digital demodulation, filtering, control resolving and modulation processing are carried out on the second modal detection signal, and stable control over gyroscope orthogonal compensation and time-sharing stable closed-loop control over the gyroscope angular rate are achieved.
Owner:XIAN FLIGHT SELF CONTROL INST OF AVIC

GEOSAR antenna pattern on-orbit measurement method

The invention discloses an on-orbit measurement method for a GEOSAR antenna pattern. The method comprises the following steps: step 1, arranging calibration equipment; 2, making a satellite observation plan; step 3, IQ digital demodulation is carried out on the signals collected by the scaler to generate baseband complex signals; step 4, performing pulse compression processing on the baseband complex signal generated in the step 3, and extracting the peak amplitude of each pulse; 5, reading satellite precise orbit determination parameters and satellite attitude measurement parameters, and converting the satellite orbit coordinate system Eb into a satellite body coordinate system Es according to a satellite attitude turning sequence; then calculating an azimuth angle corresponding to each pulse; and step 6, enabling the azimuth angle corresponding to each pulse calculated in the step 5 to correspond to the peak amplitude of each pulse extracted in the step 4, and obtaining a GEOSAR antenna pattern. The method provided by the invention has simple requirements on ground equipment and strong practicability, and is an effective and feasible GEOSAR antenna pattern on-orbit measurement method.
Owner:XIAN INSTITUE OF SPACE RADIO TECH

A method for measuring and compensating for Y waveguide waveform slope

The present application provides a Y waveguide waveform slope measurement and compensation method to solve the problem that the existing high-precision fiber-optic gyroscope Y waveguide waveform slope measurement method is based on the characteristics of the Y waveguide itself, ignoring the error of the fiber-optic gyroscope closed loop modulation wave when resetting caused by the Y waveguide waveform slope after the Y waveguide is connected with the optical path of the fiber-optic gyroscope. The present application uses the existing optical path and circuit for testing the performance of the fiber-optic gyroscope, uploads the Y waveguide waveform slope test results to the upper computer through the circuit, and when a ±23 / 8π square wave is used as a digital demodulation circuit to apply a waveform slope trigger signal, the pressure difference of the fiber-optic gyroscope demodulation signal before and after resetting is the largest. The upper computer calculates the Y waveform slope error, compensates for the error of the fiber-optic gyroscope closed loop modulation wave when resetting, improves the gyroscope precision of the fiber-optic gyroscope at a small rate of rotation, and improves the application range of the fiber-optic gyroscope.
Owner:XIAN AEROSPACE PRECISION ELECTROMECHANICAL INST

Reception apparatus, transmission system, and program

To achieve redundancy by synchronizing signals transmitted through a plurality of lines having different transmission delay times.SOLUTION: A reception apparatus 1 comprises: a digital demodulation part 31 that receives an OFDM signal having coded data modulated by OFDM from a first transmission apparatus 10, and performs an OFDM demodulation process on the OFDM signal to generate first coded data; a coded data extraction part 32 that receives a packet of coded data from a second transmission apparatus 20 and extracts second coded data from the packet; and a synchronization part 34 that synchronizes the coded data. Block numbers are set on respective blocks of the coded data. A range of numbers of OFDM frames and of block numbers of the coded data included in the OFDM frames is set on a signal for controlling transmission of the OFDM signal. The numbers of OFDM frames and the block numbers of the coded data are set on a header of the packet. The synchronization part 34 determines a synchronization position using the numbers of the OFDM frames and the block numbers.SELECTED DRAWING: Figure 1
Owner:NIPPON HOSO KYOKAI

Digital demodulation method for mining wireless electromagnetic wave scenograph

The invention relates to a digital demodulation method for a mining wireless electromagnetic wave scenograph, belongs to the technical field of mining electromagnetic wave detection, and aims at solving the problems that an existing scenograph depends on an analog filtering and rectifying circuit, so that the circuit is complex, and the reliability is poor. According to the method, after a receiver receives and amplifies an electromagnetic wave signal, the electromagnetic wave signal is sampled by an analog-to-digital conversion module, a field programmable logic gate array performs fast Fourier transform on a digital signal, and an amplitude corresponding to a transmitting frequency is extracted as an effective signal, so that digital demodulation is realized. Filtering and rectifying circuits do not need to be simulated, the circuit structure can be remarkably simplified, the reliability and the real-time performance of an instrument are improved, and the stable detection requirement in the mine environment is met.
Owner:CHINA COAL TECH & ENG GRP CHONGQING RES INST CO LTD

A chirp multi-carrier transmission method based on windowing and truncation

A chirp multi-carrier transmission method based on windowing and truncation belongs to the field of wireless communication technology. The purpose of the present invention is to achieve efficient spectrum utilization while improving the bit error rate performance. The present invention first performs digital modulation and serial-to-parallel conversion on a random bit stream sequence, then performs a discrete Fresnel inverse transform on the conversion result, and after the discrete Fresnel inverse transform result passes through a time domain truncation window, the intercepted signal is converted into parallel and serial, and the parallel-to-serial conversion result is then sent through a channel. The receiving end performs serial-to-parallel conversion, zero padding, discrete Fresnel transformation, and inter-subcarrier interference elimination on the received signal, and then digitally demodulates the signal after interference elimination to restore the original bit stream data. The present invention saves transmission time and improves transmission efficiency by performing windowing and truncation in the time domain, and the bit error rate performance is better than that of existing systems. The method of the present invention can be applied to the field of wireless communication technology.
Owner:HARBIN INST OF TECH

Portable human heart imaging hardware system based on bioelectrical impedance

The invention discloses a portable human heart imaging hardware system based on bioelectrical impedance. The system comprises an excitation signal processing module, a detection signal conditioning module and a digital processing module. The excitation signal processing module adopts a DAC (Digital-to-Analog Converter) to generate an excitation signal, and after voltage amplification and band-pass filtering, the excitation signal drives an excitation electrode through an analog switch; the detection signal conditioning module switches a measuring electrode through an analog switch, a programmable instrumentation amplifier is combined with an RDAC digital potentiometer to realize self-adaptive gain adjustment of a detection signal, flexible gain of the signal is realized, and the signal is sent to an ADC after being filtered; the digital processing module carries out digital demodulation on the collected signals, extracts amplitude and phase information and then transmits the amplitude and phase information to an upper computer for image reconstruction. The flexible signal gain mechanism of the system realizes a full-custom signal gain curve, breaks through the fixed magnification gain limitation of the traditional integrated PGA, adapts to the impedance change of different individuals and experimental media, and improves the signal-to-noise ratio of the system, thereby obtaining more accurate cardiac impedance acquisition data.
Owner:GUILIN UNIV OF ELECTRONIC TECH

A dual-wavelength synchronous detection system and method for photoacoustic-scattering aerosol based on dual-mode resonance

The application discloses a kind of based on bimodal resonance's photoacoustic-scattering aerosol dual-wavelength synchronous detection system and method, belong to photoelectric detection technical field, in the system, dual-wavelength light source modulation module generates two different frequency modulated laser, respectively from two ends into double-difference bulb pipe coupling photoacoustic-scattering combined gas cell;The gas cell includes the two ends of two acoustical tubes arranged in parallel and each is connected with an integrating sphere, form H type coupling structure;Scattering signal collection module, photoacoustic signal acquisition and processing module respectively acquire two-channel scattering photon counting data in two integrating spheres, sound wave signal in two acoustical tubes and two integrating spheres;Digital lock-in signal processing module based on FPGA outputs modulation signal to light source, and receives sound wave signal in two acoustical tubes and two integrating spheres to carry out full-digital demodulation and processing.The application effectively solves the problem of time-space asynchronization and sampling cumulative error caused by time-sharing multiplexing or multiple machine parallel connection.
Owner:HEFEI INSTITUTE OF PHYSICAL SCIENCE CHINESE ACADEMY OF SCIENCES

Laser phase noise measurement method based on time-delay self-heterodyne and digital demodulation

The application discloses a laser phase noise measurement method based on delay self-heterodyne and digital demodulation, and relates to the technical field of laser measurement, and comprises the following contents: after being adjusted by a variable optical attenuator, to-be-measured laser is divided into a frequency shift arm and a delay arm, the frequency shift arm is frequency-shifted by an acousto-optic modulator, the delay arm is delayed by a delay optical fiber, and original electric beat frequency signals are obtained by a balanced photoelectric detector after the two arms are coupled; homologous and synchronous quadrature demodulation is carried out on the original electric beat frequency signals, envelope credibility judgment and abnormal sample repair are combined, and a continuous differential phase sequence is obtained; actual optical time delay is determined according to the beat frequency spectrum characteristics and the continuous differential phase sequence, and a differential phase power spectral density is formed; then, transmission relationship conversion is carried out according to the actual optical time delay, bounded spectrum compensation is implemented on a zero point neighborhood and a low credibility frequency point, and an intrinsic phase noise power spectral density is obtained. The application can improve the stability, continuity and result credibility of phase noise measurement under the condition of short delay.
Owner:MICRO PHOTONS (SHANGHAI) TECH CO LTD

A remote transmission method and device for a short-range transmission protocol

The present invention belongs to the technical field of signal transmission, and discloses a remote transmission method and device based on a short-range transmission protocol data frame. The present invention performs digital design of digital signals by moving the high level of the idle period and the period of sending data 1 in the short-range transmission protocol data frame to the high-frequency digital carrier frequency for transmission, and not sending the digital carrier in the low-level period when sending data 0. The receiving end first samples the received modulated signal twice within a digital carrier cycle using a digital clock signal that is twice the digital carrier frequency of the transmitting end, and then performs an XOR operation on the two sampled values, thereby restoring the high level and low level in the short-range transmission protocol data frame, and realizing that the remote transmission signal receiving end directly demodulates the digital carrier signal without using relevant or non-related demodulation means and filters, thereby greatly simplifying the digital demodulation circuit.
Owner:SICHUAN TECH & BUSINESS UNIV

High-precision gyroscope multi-mode matching photoelectric integrated system

The invention relates to a multi-mode matching photoelectric integrated system for a high-precision gyroscope, which is mainly used for solving the technical problems that heat generated by heating devices in an existing optical fiber gyroscope is dispersed at two ends of an optical fiber ring module, the measurement precision of the optical fiber ring module is greatly influenced, the occupied space is large, and the miniaturization requirement cannot be met. The invention relates to a high-precision gyroscope multi-mode matching photoelectric integrated system which comprises an outer shell, and a light source, a coupler, at least one photoelectric component, a digital demodulation circuit board and a connector which are arranged on the outer shell. The light source is connected with the coupler, and the digital demodulation circuit board is connected with the photoelectric assembly, modulates and demodulates collected electric signals, outputs angular rate values and transmits the angular rate values to external equipment through a connector. According to the invention, the heating device is integrally designed in the outer shell, so that the space ratio is reduced, the heating device can be placed away from the optical fiber ring module, and a good heat insulation effect is achieved.
Owner:XIAN AEROSPACE PRECISION ELECTROMECHANICAL INST

A pulse high-voltage divider calibration device and method

The application discloses a pulse high-voltage divider calibration device and method, wherein the device comprises a pulse high-voltage source, a high-voltage voltage dividing network, a high-voltage multi-node acquisition module, a high-voltage optical fiber transmission module, a high-voltage signal demodulation module, a multi-channel acquisition module and a calibration controller. The high-voltage voltage dividing network is composed of RC parallel circuits in series and is used for dividing high-voltage signals. The high-voltage multi-node acquisition module is used for measuring pulse voltage signals after voltage division. The high-voltage optical fiber transmission module comprises a fiber transmitter and a high-voltage weather-resistant single-mode optical fiber and is used for transmitting pulse voltage signals in the form of optical signals. The high-voltage signal demodulation module comprises a fiber receiver and a digital demodulator and is used for receiving and demodulating optical signals. The multi-channel acquisition module comprises a synchronous clock source, an acquisition unit and a cache unit and is used for acquiring and storing pulse voltage signals. The calibration controller is used for calculating pulse voltage signals. The application solves the problems of a complex calibration system, weak anti-electromagnetic interference and a complicated calibration process.
Owner:CHINA ELECTRONICS STANDARDIZATION INST

A digital lock-in amplifier with a large dynamic range

This application belongs to the field of lock-in amplifier technology, specifically disclosing a large dynamic range digital lock-in amplifier, comprising: a signal generator for generating sine and cosine reference signals; a DAC for performing digital-to-analog conversion on the generated reference signal and providing the converted analog quantity to the device under test (DUT); an ADC for performing analog-to-digital conversion on the signal output by the DUT and providing the converted digital amplitude to a gain controller and a digital demodulator; a gain controller for comparing the difference between the desired voltage amplitude and the digital amplitude provided by the ADC, and adjusting the amplitude of the reference signal according to a negative feedback method; and a digital demodulator for approximating the amplitude-frequency and phase-frequency characteristics of the DUT based on the reference signal and the digital amplitude provided by the ADC through a fitting method, and outputting an estimated vector. This application adjusts the amplitude of the reference signal according to a negative feedback method to avoid the signal link entering the nonlinear region, thus achieving a large dynamic range.
Owner:HUAZHONG UNIV OF SCI & TECH

Digital demodulation type quartz MEMS tuning fork trimming device

The invention provides a digital demodulation type quartz MEMS tuning fork trimming device, and belongs to the field of MEMS tuning fork trimming. The device comprises an upper computer and a quartz MEMS tuning fork which are respectively connected with a first controller and a second controller. The upper computer is used for sending a first driving command to the first controller and sending a second driving command and a third driving command to the second controller; the second controller is used for controlling the quartz MEMS tuning fork to work in a gyro function mode according to the second driving command and the first parameter when a driving end mass block of the quartz MEMS tuning fork is roughly repaired; and the fine trimming module is used for performing linear frequency sweeping on the quartz MEMS tuning fork according to the third driving command during fine trimming to obtain a target mechanical orthogonal item, and determining that fine trimming of the driving end mass block is completed when the target mechanical orthogonal item reaches the standard. The trimming efficiency and precision can be considered through double-stage trimming and automatic control, and meanwhile the trimming cost is reduced.
Owner:BEIJING CHENJING ELECTRONICS

Receiving device and receiving method

The present invention provides a receiving device and a receiving method that can obtain an appropriate RSSI value corresponding to the signal quality of the actual received signal received by the antenna. [Solution] The receiving device and receiving method include an RSSI detection unit 13 in the receiving high-frequency unit 10 that detects a detected RSSI value from the input received signal, a signal quality level calculation unit 23 in the receiving control unit 20 that calculates the signal quality level from the received signal digitally demodulated by the digital demodulation unit 21, a virtual RSSI conversion unit 24 that converts it into a virtual RSSI value corresponding to the signal quality of the actual received signal received by the antenna, and an RSSI output display unit 25 that displays the virtual RSSI value and the detected RSSI value.
Owner:KOKUSAI DENKI ELECTRIC INC

A precision temperature measurement and control device based on a pre - placed AC bridge

The present invention discloses a precise temperature measurement and control device based on a pre - placed AC bridge. The device includes a temperature control and temperature fluctuation measurement module, an actuator driving module, and a controlled object module. Aiming at improving the temperature control accuracy and temperature stability of the temperature measurement and control device, an AC Wheatstone bridge and a subsequent digital demodulation link are adopted to reduce the noise of the front - end amplifier. Additionally, the entire Wheatstone bridge is uniquely moved to the controlled object end, and the temperature fluctuation measurement circuit and the temperature control circuit are placed on the same circuit board. This temperature measurement and control device has higher temperature control accuracy, greatly improves the stability and anti - interference ability of the system, reduces the residual temperature noise after the temperature control system operates stably in a closed - loop manner, and thus improves the temperature stability of the temperature measurement and control device after temperature control.
Owner:INNOVATION ACAD FOR PRECISION MEASUREMENT SCI & TECH CAS

Microbial electrode impedance intelligent analysis device and method

The invention relates to an intelligent microbial electrode impedance analysis device, which belongs to the technical field of electrochemical impedance spectroscopy analysis, and comprises a three-electrode system used for collecting microbial impedance signals; the response signal acquisition and conditioning module is used for preprocessing the acquired microbial impedance signal; the self-adaptive digital phase-locked amplification module adopts a synchronous orthogonal digital demodulation technology and utilizes known excitation signal digital phase information to generate an orthogonal reference signal, extract amplitude and phase information of an impedance response signal, perform self-adaptive noise suppression and decouple core parameters; the reinforcement learning optimization unit is used for evaluating a current measurement state and selecting a next frequency step length; the self-adaptive excitation module is used for generating a sine excitation voltage signal and outputting the sine excitation voltage signal to the three-electrode system; and the data display module is used for displaying the impedance spectrum and the Rct curve.
Owner:CHONGQING INST OF GREEN & INTELLIGENT TECH CHINESE ACAD OF SCI

A low-noise dual-output synchronous demodulation circuit and synchronous demodulation method

ActiveCN115987220BAngle demodulationLow noiseSoftware engineering
The present invention discloses a low-noise dual-output synchronous demodulation circuit and method. The synchronous demodulation circuit includes a signal source to be measured, a reference signal source, a pulse generator, a voltage comparator, a logic operator, a reversible counter, a digital-to-analog converter, a digital filter, and an analog filter. A sinusoidal reference signal is generated by the pulse generator as a digital pulse signal. A sinusoidal voltage signal is generated by the voltage comparator and the logic operator as a synchronized pulse count signal. The reversible counter and the digital-to-analog converter are used to obtain a digital voltage signal and an analog voltage signal. Real-time looping is used to maintain the consistency of the voltage value of the sinusoidal voltage signal when the analog voltage signal is synchronized with the digital pulse signal. This synchronous demodulation method can effectively reduce high-frequency components and improve the signal-to-noise ratio of the demodulated signal. The synchronous demodulation circuit can directly provide dual outputs of a digital demodulation signal and an analog demodulation signal.
Owner:HEFEI UNIV OF TECH

PID parameter adaptive adjustment method and system, electronic equipment and readable medium

The invention relates to a PID parameter adaptive adjustment method and system, electronic equipment and a readable medium, and the method comprises the steps: outputting an analog voltage signal corresponding to an expected gradient waveform to a gradient amplifier through a gradient output module, so as to form an actual current corresponding to the analog voltage signal through the gradient amplifier; a voltage feedback signal which is output by the gradient amplifier and corresponds to the actual current is transmitted to the spectrometer radio frequency module; performing amplitude modulation and frequency mixing on the voltage feedback signal through a spectrometer radio frequency module to obtain a frequency mixing signal; digital sampling and digital demodulation are carried out on the frequency mixing signal through an optical fiber box, and an actually measured gradient waveform is obtained; and calculating a time domain error between the expected gradient waveform and the actually measured gradient waveform, and under the condition that the time domain error is greater than a target error, adaptively adjusting the PID parameter according to the error type of the actually measured gradient waveform until the time domain error is less than the target error. The problem that the PID parameters of the gradient amplifier are difficult to adaptively calibrate accurately is solved.
Owner:BEIJING WANDONG MEDICAL TECH CO LTD

Low-power analog front-end circuit applied to animal tag and control method

This invention discloses a low-power analog front-end circuit and control method for animal tags. The circuit includes: a radio frequency (RF) unit, a power management unit, and an antenna. The power management unit includes a rectifier and a low-power power management circuit. The rectifier is connected to the antenna. The low-power power management circuit supplies power to the RF unit and digital circuits. The RF unit includes a load modulation and limiting circuit, a demodulation circuit, and a clock generation circuit. The demodulation circuit receives the demodulated envelope signal sent by the rectifier and outputs digital demodulated data to the digital circuits. The clock generation circuit extracts a clock signal from the antenna signal generated by the antenna and outputs the clock signal to the digital circuits. The load modulation and limiting circuit receives the limiting reference voltage sent by the rectifier and the uplink data output by the digital circuits. In this embodiment, an animal identification tag adapted for wireless communication achieves a balance between low power consumption and small area while ensuring communication reliability.
Owner:SOUTH CHINA NORMAL UNIV

Digital phase-locked amplifier with large dynamic range

The invention belongs to the technical field of phase-locked amplifiers, and particularly discloses a large-dynamic-range digital phase-locked amplifier, which comprises a signal generator, a phase-locked amplifier, a phase-locked amplifier circuit and a phase-locked amplifier circuit, the DAC is used for performing digital-to-analog conversion on the generated reference signal and providing an analog quantity obtained by conversion to the device to be tested; the ADC is used for performing analog-to-digital conversion on a signal output by the device to be tested, and providing a digital amplitude obtained by conversion to the gain controller and the digital demodulator; the gain controller is used for comparing the difference between the expected voltage amplitude and the digital amplitude provided by the ADC and adjusting the amplitude of the reference signal according to a negative feedback mode; and the digital demodulator is used for approaching amplitude-frequency phase-frequency characteristics of the device to be tested through a fitting mode based on the reference signal and the digital amplitude provided by the ADC, and outputting an estimation vector. The amplitude of the reference signal is adjusted according to a negative feedback mode, so that a signal link is prevented from entering a nonlinear interval, and a large dynamic range can be realized.
Owner:HUAZHONG UNIV OF SCI & TECH

A MF-TDMA frequency hopping anti-interference system based on secondary interference judgment

The present invention relates to an MF-TDMA frequency hopping anti-interference system based on secondary interference judgment. The method includes an AD sampling unit, a digital branch filtering unit, a power estimation and secondary interference judgment unit, and a digital demodulation unit. Combining the characteristics of the MF-TDMA system, the method performs power estimation after AD sampling and power estimation after digital branch filtering on multi-carrier signals. The method utilizes the two power estimates combined with secondary interference judgment to accurately detect and identify interference. Furthermore, based on a joint discrimination flag, the method determines whether the signal participates in timing error calculation and data interpolation. Furthermore, the method scales the useful signal through digital forward automatic gain control (AGC). This method can effectively counteract the effects of narrowband interference on a multi-mode, multi-carrier frequency hopping anti-interference communication system.
Owner:XIAN INSTITUE OF SPACE RADIO TECH

Novel radio station based on voice recognition and translation

The invention discloses a novel radio station based on voice recognition and translation, which is characterized in that voice recognition is carried out on the voice of a sender to generate corresponding language coding information, the information is modulated by a digital modulation module and then forms a radio frequency signal through a frequency mixing amplification module, and the radio frequency signal is transmitted to the air through an antenna; after receiving a radio frequency signal through an antenna, the receiving station generates an intermediate frequency digital modulation signal through a frequency mixing amplification module, then demodulates the intermediate frequency digital modulation signal into language coding information of a speaker of the transmitting station through a digital demodulation module, and forms language digital voice information corresponding to a listener of the receiving station after the language coding information is processed by a voice translation module in a voice processing module. The digital-to-analog signal conversion is realized through the D / A conversion module, the analog signal is sent to the earphone through the power amplification module to form a voice message which can be understood by a receiver, the occupied bandwidth is far smaller than that of a traditional radio station, and meanwhile, barrier-free cross-language communication can be realized.
Owner:CHINESE PEOPLES LIBERATION ARMY UNIT 93995

Magnetic encoder

The invention discloses a magnetic encoder, and the encoder comprises a magnetic sensor which is used for generating an amplitude modulation signal in a rotating magnetic field under the drive of a high-frequency AC signal; the two magnetic switch elements generate orthogonal pulse signals with phase difference in the rotating magnetic field, and the orthogonal pulse signals serve as additional quadrants; the signal processing unit is used for generating a high-frequency alternating current signal; signal processing is carried out on the amplitude modulation signal output by the magnetic sensor to obtain a digital demodulation signal, and the signal processing sequentially comprises differential-to-single-ended processing, amplification processing, high-pass filtering processing and demodulation processing; position information is calculated based on the digital demodulation signal and the additional quadrant. The magnetic encoder provided by the invention improves the resolution of the rotation angle of the rotor.
Owner:ZHEJIANG REAGLE SENSING TECHNOLOGY INC