42 results about "Frequency demodulation" patented technology

The invention belongs to the technical field of new energy automobile lithium battery thermal runaway early warning, and particularly discloses a lithium battery thermal runaway gas early warning system. The method is used for solving the problem that thermal runaway cannot be rapidly and accurately detected and early warning cannot be carried out in advance in the existing monitoring technology. The early warning system comprises a main control unit, a core processing unit, a graphical user interface, a dual-frequency driving signal generation circuit, a spectral signal dual-frequency demodulation circuit, a temperature control circuit, a constant current source and overcurrent protection circuit, a spectral data acquisition circuit, a graphical user interface, an optical system, a gas sampling device and an early warning model. The power supply of the early warning system adopts a three-stage voltage reduction design, and comprises an AC-DC switching power supply, a DC-DC switching power supply and a low dropout regulator. Based on the off-axis integral cavity optical path coupling technology of the double-optical wedge group, the light beam angle is accurately adjusted through the double optical wedges of the stepping motor, a beam combiner does not need to be used, and the light energy utilization rate and the detection sensitivity are improved.

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.

The invention provides an online detection system and method for electrochemical alternating-current impedance of a fuel cell, and aims to solve the problems of limited measurement frequency range and insufficient control precision caused by bandwidth limitation of a controller in the existing EIS online detection technology, and the online detection system comprises a fuel cell and a power supply system of a DC-DC converter, the disturbance signal generation module generates a sine disturbance current signal; the feedforward and feedback control module takes the total current reference signal as a control target, and calculates to obtain a final adjustment duty ratio for driving the DC-DC converter; when the DC-DC converter is driven by the final adjustment duty ratio, a data acquisition module synchronously acquires an input voltage and an input current which are input into the DC-DC converter as a response voltage signal and a response current signal; and the impedance demodulation module is used for demodulating and calculating the electrochemical alternating current impedance of the fuel cell based on the frequency of the response voltage signal, the response current signal and the sine disturbance current signal.

Radiofrequency module (1) intended to be embedded in a motor vehicle, and comprising: a transmission and reception module (10), comprising an antenna (3) for the transmission of a pulse-modulated radiofrequency signal called transmitted signal (101) and the reception of a received signal (102) returning to the antenna (3), and a detection circuit (2) for carrying out at least one frequency demodulation of the received signal so as to provide signals I(t) and Q(t) corresponding to the in-phase and quadrature-phase components of a frequency-demodulated received signal; a signal extraction module (6), for extracting a first contribution from the frequency-demodulated received signal, corresponding to internal reflections of the transmitted signal (101) inside the antenna (3);and a first signal processing module (7), for receiving said first contribution, and for deducing therefrom information relating to a user presence using a comparison with a predetermined threshold. Figure for the abstract: Fig 1;

A second device comprises at least one ADC. The ADC(s) are configured to receive a composite analog signal. The composite analog signal comprises a plurality of modulated signals. Each signal in the modulated signals has been modulated to a distinct center frequency. Each signal in the modulated signals has originated from a sensor. At least two of the signals in the modulated signals comprise a plurality of frequency components. The ADC(s) are configured to convert the modulated signals into a digital signal. The second device comprises at least one control unit. The control unit(s) are configured to receive the digital signal. The control unit(s) are configured to perform: band pass filtering, frequency demodulation, and extraction of the signals sensed by the sensors.

To provide a wireless communication device that can perform carrier sensing even when leakage occurs in the modulator. [Solution] The wireless communication device according to the embodiment comprises a first filter, an oscillator circuit, a modulation circuit, and a demodulator. The first filter restricts the input signal to a first passband. The oscillator circuit outputs a first signal with a frequency outside the first passband. The modulation circuit modulates the first signal to a second signal that detunes a predetermined frequency from the frequency at which the received signal strength is measured. The demodulator demodulates the signal that has passed through the first filter based on the second signal.

The application provides a high-reliability ultra-small high-speed switch patch diode structure, which comprises a patch diode tube body, pins are arranged at the left and right ends of the bottom of the patch diode tube body, a limiting rod is arranged in the patch diode tube body, a push plate is arranged at the bottom of the limiting plate, reinforcing strips are arranged at the side edges of the push plate, a screw rod is arranged at the bottom of the reinforcing strip, a screw cap is arranged at the top of the screw rod, a pad is arranged at the side edge of the screw rod, a sealing plate is arranged at the side edge of the pad, and an adjusting hole is arranged in the sealing plate. The high-reliability ultra-small high-speed switch patch diode structure is mounted at the bottom of the patch diode tube body through the pins, the receiving capacity of the patch diode tube body is improved, meanwhile, the pins can be used in an unbalanced way to enter the internal frequency demodulation circuit for demodulation through the pins, the resistance can obtain a high-level signal through the pins, and when no signal is received, the pins present low impedance and output a low-level signal.

The invention discloses a non-intrusive monitoring method for a blade root load of a wind driven generator based on a vibration signal and deep learning. When the alternating load acts on the roots of the blades, energy is transmitted to the engine through all parts of the transmission system, and vibration is generated in the process. Therefore, BRL characteristic changes exist in the time domain or the frequency domain of the vibration signal, and meanwhile, a low-frequency demodulation component is introduced into the vibration signal. However, these features are easily masked by high-frequency components and strong background noise, and since the BRL change period is long, the length of the vibration signal also needs to be long enough to ensure that BRL change information within the period can be covered. Based on AE-LSTM-Attention, high-precision prediction of the BRL is realized through multi-channel vibration signal acquisition, auto-encoder noise reduction, LSTM time sequence modeling and channel attention fusion.

The application discloses a microwave signal and energy co-transmission system based on frequency modulation and amplitude modulation, and belongs to the technical field of electric communication. The microwave signal and energy co-transmission system comprises a microwave signal source, a frequency modulator, a power amplifier, an amplitude modulation transformer, a transceiving antenna, a directional coupler, a frequency demodulator, a rectifier circuit, a maximum power point tracking module, a load and a control unit. The frequency modulator and the frequency demodulator are jointly matched to realize information loading and analysis without affecting energy transmission. The maximum power point tracking module adopts a Boost circuit and a maximum power point tracking algorithm to realize power / efficiency improvement of the rectifier circuit at the receiving end. The amplitude modulation transformer adopts a Buck circuit to supply power for the power amplifier, the control unit acquires input voltage and input current of the amplitude modulation transformer as well as load voltage and load current, executes a maximum efficiency point tracking algorithm, and dynamically adjusts output voltage of the amplitude modulation transformer, so that the system stably works at a maximum efficiency point.

To determine the cadence of a rider of a bicycle 1 equipped with at least one sensor for torque measurement, angle measurement, or cadence measurement, a cadence signal correlated to the rider's cadence is constructed from a time-varying signal waveform of a raw signal from the sensor using at least one frequency demodulator. The constructed cadence signal can be used to control or regulate an electric drive motor or actuator of the bicycle, or both an electric drive motor and an actuator. Alternatively or additionally, the constructed cadence signal can be used to validate a cadence signal from the sensor used for cadence measurement or another constructed cadence signal. This method eliminates the need for at least one dedicated sensor to measure cadence, thus reducing costs. Plausibility checks can prevent incorrect activation or control of a bicycle's electric drive motor or actuator, thereby minimizing the risk of accidents or injuries to the cyclist.

The present invention is a multi-target vital sign detector and its detection method. The multi-target vital sign detector includes a self-injection locked oscillator, a chirp up / down frequency converter, a frequency demodulation unit, and a multi-target vital sign processing unit. The chirp up / down frequency converter converts the oscillation signal of the self-injection locked oscillator into a frequency-modulated continuous wave signal to detect an area, and converts the received frequency-modulated continuous wave signal reflected by the area into an injection signal. The injection signal is injected into the self-injection locked oscillator to make it in a self-injection locked state. Finally, the positions and vital signs of multiple organisms are obtained from the oscillation signal through the frequency demodulation unit and the multi-target vital sign processing unit. The purpose of using the self-injection locked oscillator is to improve the sensitivity of the frequency-modulated continuous wave detector, and effectively distinguish the vital signs of multiple organisms located at different positions.

A power supply device (18; 33) and a portable device (19; 34) and a system (17; 32) for wirelessly charging a battery (20) of a portable device (19, 34), the power supply device (18; 33) comprising a power transmitter stage and a power receiver stage connected to a power antenna (25), the portable device (19; 34) comprises a portable transmitter stage and a portable receiver stage connected to a portable antenna (31), where the power transmitter stage is configured to generate a magnetic field in the RFID frequency range and to modulate it with transmitter data and to transmit the modulated magnetic field with a power antenna (25), and the portable receiver stage is configured to receive the modulated magnetic field from the power antenna (25). The portable receiver stage is configured to receive an antenna signal (30) from a receiver antenna (31) exposed to a modulated magnetic field, and to demodulate transmitter data and to rectify the antenna signal to charge a battery (20) during a charging period, the portable transmitter stage is configured to modulate the magnetic field with portable transmitter data using amplitude modulation, and to charge the battery (20) during a charging period. The power receiver stage is configured to demodulate portable transmitter data, the portable transmitter stage is configured to transmit power adjustment data to increase or decrease the power required to charge the battery (20) transmitted with a magnetic field transmitted with a power antenna (25) of the power transmitter stage, the power receiver stage is configured to receive power adjustment data and to direct the power transmitter stage to transmit more or less power in the generated magnetic field, wherein the power supply device (18; 33) and a portable device (19; 34) is constructed in an active charging mode, and wherein the power transmitter stage in the active charging mode is constructed to add a function of modulating the magnetic field using frequency modulation to at least transmit power adjustment data, and wherein the portable receiver stage in the active charging mode is configured to process frequency demodulation of the antenna signal (30) to receive at least the power adjustment data.

The present application relates to an inductive position sensor, comprising a microcontroller unit, a mover, and a stator, and further comprising: a signal amplification circuit for amplifying the sensing signal, wherein the sensing signal is a differential signal; a low-frequency filtering circuit, wherein the low-frequency filtering circuit receives the amplified sensing signal and performs high-pass filtering or band-pass filtering on the sensing signal to filter out the low-frequency signal; a demodulation circuit, which receives the sensing signal filtered by the low-frequency filtering circuit and demodulates the sensing signal into a low-frequency demodulation signal; a high-frequency filtering circuit, which receives the demodulated signal and performs low-pass filtering on the demodulated signal to filter out the high-frequency signal; and the microcontroller unit receives the demodulated signal filtered by the high-frequency filtering circuit and converts the demodulated signal into position information.

The invention discloses a signal demodulation method and system based on an ion coherent vibration state, and belongs to the technical field of communication, and the method comprises the steps: obtaining coherent vibration state ions and standard signals of different modulation types, enabling the coherent vibration state ions to fluctuate along with the code element change of the standard signals, and obtaining standard fluctuation ions; measuring standard fluctuation ions to construct a modulation feature library; acquiring a to-be-demodulated signal, and enabling the coherent vibration state ions to fluctuate along with the code element change of the to-be-demodulated signal to obtain fluctuating ions; based on the modulation feature library, performing matching identification on the amplitude and the phase of the fluctuating ions to complete signal demodulation on the to-be-demodulated signal: when the amplitude jumps and the phase is unchanged, performing amplitude demodulation; when the amplitude and the phase jump at the same time and jump directions are opposite, phase demodulation is carried out; and when the jump of the amplitude and the phase presents a sine periodic rule, frequency demodulation is carried out. According to the method disclosed by the invention, the demodulation accuracy and applicability of the communication system can be improved.

The disclosure pertains to a time-of-flight image sensor circuitry that includes an imaging unit with a first imaging portion and a second imaging portion, wherein the circuitry is further configured to apply a low-frequency demodulation signal that has a first state and a second state, and apply a high-frequency demodulation signal, wherein, when the low-frequency demodulation signal is applied in the first state to the first imaging portion, the high-frequency demodulation signal is applied to the second imaging portion.

The invention discloses a method, system and device for improving BOTDR system performance and a storage medium, and relates to the technical field of optical fiber sensing, and the method comprises the steps: using a single narrow linewidth laser to output light, dividing the light into three paths through an optocoupler, carrying out the shunting processing, carrying out the light splitting processing of a Brillouin scattering signal returned by a to-be-measured optical fiber, and obtaining a Brillouin scattering signal; after being divided into two paths, different beat frequency interference operations are respectively carried out; processing the high-frequency beat frequency electric signal to obtain a Brillouin frequency shift obtained through beat frequency demodulation of a reference optical fiber signal and a Brillouin frequency shift obtained through direct beat frequency demodulation of local light; according to different temperature and stress change conditions, results demodulated by different light paths are judged and processed; according to the invention, the performance of the Brillouin optical time domain reflection system can be effectively improved; the reference light frequency is stabilized, and measurement errors are reduced; the frequency sweeping range is widened, and various monitoring requirements are met; the radio frequency design is simplified, and the signal amplification stability is improved.

The invention discloses a dual-frequency dual-modulation communication method and application in a transformer winding deformation tester, and the method comprises the steps: transmitting two pieces of different digital information, namely information A and information B, and transmitting the information A to a direct digital signal generator capable of storing two pieces of different frequency information at the same time; a sine wave signal with a standard amplitude and corresponding to the information A is arranged through an operational amplifier; amplitude amplification is carried out after frequency multiplication, the amplification multiple is related to the information B, and finally a group of mixed air radio frequency signals are formed; performing power amplification on the received signal, and dividing the amplified signal into two paths; one path is subjected to amplitude calibration and power demodulation to obtain transmitted information B, and the other path is subjected to high-pass filtering and frequency demodulation to obtain transmitted information A; when the radio frequency technology is used for space communication, two groups of different information are transmitted at the same time, one-to-many communication requirements can be met, and communication delay and timing sequence disorder of receiving equipment cannot be caused.

The invention discloses a demodulation method and system suitable for an optical fiber hydrophone array. An optical signal is modulated to generate a modulated optical signal; an optical fiber hydrophone array is used for sensing underwater acoustic signals, and phase modulation carrier waves are generated in interference optical signals output by optical fiber hydrophones through a PGC phase generation carrier wave modulation method; the interference optical signal is converted into an electric interference signal, the electric interference signal is sampled with the frequency 12 times that of the phase modulation signal, at least three sampling points are obtained, and the first sampling point is located at the initial phase of the phase modulation carrier; performing differential operation on the sampling signal to obtain a first detection signal and a second detection signal; and calculating a phase result based on the first detection signal and the second detection signal after negation processing, and carrying out filtering and down-sampling output on the phase result to complete phase demodulation. According to the invention, the pulse width required by a traditional demodulation method can be narrowed, the repetition frequency of a system inquiry light pulse is improved, and the demodulation design of narrow pulse width and high repetition frequency is realized.

Radio frequency module (1) intended to be carried in a motor vehicle, and comprising: a transmitting and receiving module (10), including an antenna (3) for transmitting a pulsed-modulated radio frequency signal called the transmitted signal (101) and receiving a received signal (102) returning to the antenna (3), and a detection circuit (2) for performing at least one frequency demodulation of the received signal so as to provide signals I(t) and Q(t) corresponding to the in-phase and quadrature-phase components of a frequency-demodulated received signal; a signal extraction module (6), for extracting a first contribution from the frequency-demodulated received signal, corresponding to internal reflections of the transmitted signal (101) inside the antenna (3);and a first signal processing module (7), to receive said first contribution, and to deduce information relating to a user's presence by means of a comparison to a predetermined threshold. Figure for the abstract: Fig 1;

The invention discloses a multi-step impedance converter microwave sensing system based on parallel open circuit branches. By introducing the lossy microstrip line impedance formula, the optimal size of the impedance transformer under the condition of maximizing the transmission coefficient phase change rate is obtained, then the differential model of the output direct-current voltage and the dielectric constant is constructed, the optimal solution of the sensitivity is solved under the condition of considering the loss of the liquid to be detected, and therefore the detection performance is remarkably improved. In order to reduce the detection cost, a multi-step impedance converter is used as a load network, a reflection type radio frequency oscillator is designed according to a negative impedance theory, and the change characteristic of a dielectric constant is converted into oscillation frequency change. Furthermore, a frequency demodulation circuit is carried to demodulate the change of the oscillation frequency into the change of the direct-current voltage, so that the equipment cost is reduced. The microwave micro-flow sensor provided by the invention has the advantages of high sensitivity, convenience in detection and the like, and plays an important role in industrial and agricultural production.

The invention discloses a high-speed sweep frequency light source for a Rayleigh frequency demodulation method in optical fiber distributed sound wave sensing, which consists of a light source module, a time stretching module and a buffer module, and is characterized in that firstly, a system takes an amplified spontaneous emission light source as a core light source to output wide-spectrum continuous light; the acousto-optic modulator is used for chopping to realize broadband pulse light output; then, the optical signals are introduced into a dispersive medium with a certain length, and the optical signals with different frequencies in the spectrum are uniformly spread in time by using the dispersion characteristic of the medium, so that the linear tuning process of the frequency along with the time is realized; and finally, multiplication of repetition frequency is realized through a method of forming a buffer by an optical fiber delay line, so that rapid frequency time scanning is realized. According to the invention, the frequency time scanning speed of the system is obviously improved, the real-time detection requirement of a dynamic signal can be effectively met, and the method is suitable for a high-frequency response scene in the field of optical fiber distributed sensing.

The utility model discloses a satellite communication transceiver based on a UHF (Ultra High Frequency) frequency range, relating to the field of satellite communication transceivers, aiming at solving the problem that TDM (Time Division Multiplexing) broadcast signals are easily interfered in the prior art, and adopting the technical scheme that a receiver is divided into a service processing unit and a TDM processing unit by a power divider; a frequency mixer is arranged in each processing unit, a one-time down-conversion and zero-intermediate-frequency demodulation scheme is formed after direct frequency reduction through the frequency mixers, and a large dynamic range can be obtained by combining a radio frequency filter, an intermediate frequency filter, a baseband filter and a low-noise power amplifier, the smoothness of a radio frequency front end is ensured when a large interference signal is received, the noise coefficient is small, and the signal quality is improved. Therefore, the receiver has high sensitivity and certain anti-interference capability at the same time.

The invention discloses a time addressing frequency sweep demodulation method for an identical fiber grating array, which comprises the following steps of: forming a time addressing table of each Bragg grating according to the time position of each Bragg grating in the identical fiber grating array, so as to obtain a time addressing frequency sweep of each Bragg grating under different scanning wavelengths; according to the time addressing table, effective signals corresponding to all Bragg gratings in reflected light signals output by the identical fiber grating array are collected and subjected to analog-to-digital conversion, so that effective time domain signals of the identical fiber grating array under different scanning wavelengths are obtained; and according to the effective time domain signals of the identical fiber grating array under different scanning wavelengths, the reflection spectrum corresponding to each Bragg grating is reconstructed. The time addressing frequency sweeping demodulation method has the advantages of small data acquisition amount and calculation amount, low calculation complexity, low power consumption and the like, and meanwhile, the requirement on high-performance hardware is also low. The invention further discloses an optical time domain reflection sensing system based on the method.

The present invention relates to a radio frequency module (1) to be installed on a motor vehicle, comprising: a transmitting and receiving module (10) comprising an antenna (3) for transmitting a pulsed modulated radio frequency signal called a transmission signal (101) and for receiving a reception signal (102) returned to said antenna (3), and a detection circuit (2) for performing at least one frequency demodulation of said reception signal to provide signals I(t) and Q(t) corresponding to in-phase and quadrature components of the frequency demodulated reception signal; a signal extraction module (6) for extracting a first contribution of the frequency demodulated reception signal, said first contribution corresponding to internal reflections of the transmission signal (101) inside the antenna (3); and a first signal processing module (7) for receiving said first contribution and deriving therefrom information relating to the presence of a user by comparison with a predetermined threshold.

A SIL monopulse radar includes a self-injection-locking oscillator (SILO), a transmit antenna, two receive antennas, a hybrid coupler, a first demodulator, a second demodulator and a processor. The transmit antenna transmits the oscillation signal of the SILO to object. The two receive antennas receive a reflected signal from the object as a first echo signal and a second echo signal. The hybrid coupler outputs a difference signal and a sum signal. The difference signal is injected into the SILO. The first demodulator frequency-demodulates the oscillation signal to produce a first demodulated signal. The second demodulator phase-demodulates the sum signal by using the oscillation signal as a reference signal to produce a second demodulated signal. The processor processes the first and second demodulated signals to produce a monopulse ratio signal. The SIL monopulse radar can identify the posture and motion of a human body by analyzing the monopulse ratio signal.

The invention discloses an endoscope system based on frequency domain fluorescence lifetime imaging, which is characterized in that an ICG fluorescent agent in tissues is excited by setting a dual-frequency demodulation excitation signal, so that the problem that deviation is easy to occur in fluorescence lifetime calculation if a single-frequency signal is interfered can be solved. A double-frequency modulation mode is adopted, different adjustment frequencies can be set according to sensitivity differences of ICGs in different states, the problem that signals are submerged or analysis resolution is insufficient is avoided, independent life parameters in a free state and a combined state can be directly separated from double-frequency signals through a CNN deep learning model, false images and edge blur are eliminated, and the accuracy of the ICGs in different states is improved. Accurate data are provided for clinical molecular level diagnosis, and the problem that a traditional fluorescent endoscope only depends on fluorescence intensity and is easily interfered by factors such as ICG concentration and uneven illumination is solved.

The application provides an on-line detection system and method for fuel cell electrochemical impedance, aiming at solving the problems of limited measurement frequency range and insufficient control precision caused by controller bandwidth limitation in the existing EIS on-line detection technology, comprising a power supply system of a fuel cell and a DC-DC converter, a disturbance signal generation module generating a sinusoidal disturbance current signal; a feedforward and feedback control module taking a total current reference signal as a control target and calculating a final adjustment duty cycle for driving the DC-DC converter; a data acquisition module synchronously acquiring an input voltage and an input current of the DC-DC converter as a response voltage signal and a response current signal when the DC-DC converter is driven by the final adjustment duty cycle; and an impedance demodulation module for demodulating and calculating the electrochemical impedance of the fuel cell based on the frequency of the response voltage signal, the response current signal and the sinusoidal disturbance current signal.

The invention discloses an unmanned aerial vehicle visual signal time-frequency demodulation and pose calculation method for a high-dynamic illumination environment, and aims to solve the problems of weak strong light interference resistance, insufficient pose calculation robustness and single control strategy in the prior art. The method comprises the following steps: firstly, collecting a continuous image sequence, constructing a pixel-level time domain signal, extracting a target light spot with a specific carrier frequency through frequency domain transformation, and filtering out strong light interference; resolving a pose through a PnP algorithm and calculating a re-projection residual error, dynamically adjusting a Kalman filter to observe a noise covariance according to the pose and the re-projection residual error, and outputting optimal state estimation; and finally, realizing loose / tight coupling dual-mode control switching according to the distance and the residual error. The method significantly improves the positioning signal-to-noise ratio and robustness in a high-dynamic illumination environment, gives consideration to the flight safety and control precision of the unmanned aerial vehicle, and is suitable for the navigation task of the unmanned aerial vehicle in a complex illumination scene.