20 results about "Frequency demodulation" patented technology

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.

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 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 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 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.

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.

The application discloses a kind of remote sensing image road extraction methods based on frequency domain modulation, belong to remote sensing science and technology field.For the problem that the existing road extraction method is under complex scene, fine-grained road is missed, high-frequency information is easy to lose in downsampling, and there are many artifacts in upsampling, the application modulates the effective high-frequency features of road to the low-frequency region by adaptive resampling frequency domain modulation before downsampling to avoid loss;Before upsampling, the road features stored in low frequency are restored to high frequency region by adaptive upsampling frequency demodulation, and the road segmentation result is output in combination with codec architecture.The application can effectively reduce the missing rate of small roads, improve the completeness of road boundaries, and improve the average intersection-over-union by 2.11% compared with the suboptimal method on Massachusetts road dataset, and is suitable for road information extraction in urban planning, emergency rescue and other scenarios.

The invention belongs to the technical field of surface acoustic wave sensor signal processing, and discloses a surface acoustic wave sensor detection circuit based on LMS adaptive filtering, which comprises an analog detection circuit and a digital detection circuit, the analog detection circuit comprises an SAW oscillation circuit and a frequency mixing circuit, the digital detection circuit adopts an adaptive filtering module to filter a signal output by the analog detection circuit, and the frequency demodulator receives the filtered signal and performs frequency demodulation on the signal; the SAW oscillation circuit comprises a reference channel and a measurement channel, a reference channel signal and a measurement channel signal pass through the frequency mixing circuit to obtain an offset frequency signal, and the frequency of the offset frequency signal is the frequency of a physical quantity to be measured. Through the LMS adaptive filtering module, coefficients can be dynamically adjusted to suppress time-varying noise, the defect of fixed parameters of a traditional analog filter is overcome, the signal-to-noise ratio is improved, and the LMS adaptive filter is suitable for industrial automation, aerospace and other detection scenes.

The invention provides a nuclear magnetic resonance gyroscope main magnetic field measurement method based on rotating magnetic field phase compensation. The method comprises the following steps: separating magnetic resonance signals of 129Xe nuclear spin and 131Xe nuclear spin in a nuclear magnetic resonance gyroscope; respectively demodulating the frequencies of the separated 129Xe nuclear spin magnetic resonance signal and the 131 Xe nuclear spin magnetic resonance signal by using a high-speed digital phase-locked loop, and carrying out summation operation on the two demodulated frequencies to obtain a sum frequency measurement signal; a rotating magnetic field simulating nuclear spin magnetic resonance is synthesized and generated; measuring a coupling phase error generated when the nuclear spin magnetic resonance signal is measured by electron spin to obtain an error compensation amount; and performing differential operation on the error compensation amount and the sum frequency measurement signal, and calculating to obtain an accurate value of the main magnetic field to be measured. According to the technical scheme, the technical problem that in the prior art, differential mode errors caused by precession phase coupling of paramagnetic resonance electron spinning and nuclear spinning are difficult to effectively restrain, and consequently the main magnetic field measurement precision is low is solved.

The invention discloses an intelligent infrared thermal radiation physiotherapy lamp based on single-snapshot multi-frequency demodulation-spatial frequency domain imaging, and relates to the technical field of infrared thermal radiation physiotherapy lamps. The multi-modal skin injury assessment model integrates the double advantages of convolutional neural network image recognition and random forest multi-parameter analysis, can output a three-level curative effect assessment result in real time, and drives the infrared regulation and control module to dynamically optimize the wavelength, the light intensity and the irradiation time; the temperature control device and the emergency braking system form a double-guarantee mechanism, so that the skin temperature is strictly stabilized in a safety interval of 40-50 DEG C, and the risk of thermal damage is effectively avoided; through the combination of a single-snapshot multi-frequency demodulation-spatial frequency domain imaging technology and an intelligent regulation and control system, the problems that an existing device cannot monitor the skin state in real time, treatment parameters are single and fixed, and personalized adjustment is lacked are effectively solved, and the accuracy, safety, efficiency and application range of infrared thermal radiation physiotherapy are remarkably improved.

The application discloses a frequency hopping communication synchronization system and method, and relates to the field of frequency hopping communication. The information module, the insertion frequency hopping sequence related information module, the information modulator and the frequency modulator in the transmitter in the system are sequentially communicated. The first frequency hopping sequence generator, the first frequency table and the frequency modulator are sequentially communicated. The frequency modulator is communicated with the transmitting antenna. The receiving antenna, the frequency demodulator, the information demodulator, the acquisition frequency hopping sequence related information module, the frequency hopping synchronization module, the second frequency hopping sequence generator and the second frequency table in the receiver are sequentially communicated. The second frequency table is further communicated with the frequency demodulator. The application can improve the synchronization speed and reduce the complexity of calculation under the premise that the frequency hopping sequence has the characteristics of high randomness and long period.