27 results about "Modulation demodulation" patented technology

The application discloses a kind of time division multiplexing three-axis wide spectrum light source resonant type fiber-optic gyroscope detection systems and methods, belong to gyroscope optical system design field.System is constituted by optical system and signal detection system, and optical system includes a wide spectrum light source, a push-pull Y waveguide, a circulator, three mutually orthogonal transmission type fiber ring resonant cavity, two sections of delay optical fiber and a photoelectric detector;Signal detection system includes modulation and demodulation module, time division decoupling module and low-pass filter module.Three transmission type fiber ring resonant cavities are sequentially connected, and the time of optical signal reaching three fiber ring resonant cavities is different by being set delay optical fiber between adjacent two transmission type fiber ring resonant cavities.The application ingeniously designs three fiber ring resonant cavities to form three-axis integrated structure.In this way, the time difference of three-axis signals is utilized, and multiplexing in time domain can be realized without adding additional devices.

This invention discloses a polarization state modulation method based on regular polyhedral constellation points, comprising: selecting the order of polarization modulation and the corresponding regular polyhedral class; dividing the original binary bitstream into a conventional modulation bitstream and a polarization state modulation bitstream, wherein the conventional modulation bitstream is used to generate conventional modulation symbols, and the polarization state modulation bitstream is used for polarization state mapping; obtaining the corresponding polarization state description parameters using the polarization state modulation bitstream and the order of polarization modulation, determining the polarization weighting factor and performing polarization weighted fusion to obtain dual-channel high-dimensional modulation symbols to be transmitted; transmitting the symbols through an orthogonal dual-polarization antenna after preprocessing; performing RF front-end processing on the received horizontal and vertical polarization components of the RF signal at the receiving end to obtain the Jones vector representation of the baseband received signal; recovering the polarization state information by combining the Stokes parameters, and recovering the original binary bitstream by combining the conventional modulation and demodulation results.

This invention relates to the field of optical resonator locking technology, and discloses a modulation-free optical resonator locking method and apparatus based on optical field spatial mode mismatch, aiming to solve the problems of complexity and noise introduction in traditional PDH locking technology systems. This method uses the superposition field of the spatial fundamental mode and the second-order transverse mode excited by mode mismatch as the input light field of the optical cavity. After breaking the mode orthogonality through pinhole clipping, the reflected light is split and a controllable Gouy phase shift is introduced. Two photodetectors detect the signals and differentially process them to generate an error signal, thus achieving optical resonator locking. This invention requires no external modulation and demodulation components, has a simple structure, high stability, and locking effect comparable to traditional PDH methods. It has low requirements for spot centering and partition consistency, providing a simple and effective way to achieve cavity frequency stabilization in precision optical systems, and is suitable for fields such as laser frequency stabilization and precision measurement.

This invention relates to the field of optical signal demodulation, specifically to a parallel optical signal modulation and demodulation method and system based on MicroLED array optical interconnects, comprising: a data acquisition module for acquiring raw data from the external environment or equipment and converting it into a form suitable for subsequent processing; a data processing module for receiving information from the data acquisition module and preprocessing it; and a data analysis module. The overall architecture of high-speed DSP+MicroLED channels breaks away from the traditional approach of "hundreds of channels, DSP-free, wide but slow." By introducing SerDes and DSP modulation and demodulation, the single-channel rate is increased by an order of magnitude, achieving a total bandwidth of ≥120Gbps with ≤32 channels. Simultaneously, single-channel 10–20Gbps OOK / PAM4 modulation is achieved: clearly defining high-order modulation of MicroLED under GHz-level bandwidth conditions, overcoming the carrier lifetime limitations of MicroLED, and ensuring low bit error rate through pre-emphasis, equalization, and FEC.

A method for detecting and adaptively compensating for ultra-low frequency weak vibrations in a MEMS accelerometer includes: a multi-channel parallel coherent modulation and demodulation module acquiring differential capacitance signals of the sensitive units in the MEMS accelerometer through n parallel coherent detection links, and then synchronously modulating and coherently demodulating the differential capacitance signals to obtain n baseband signals; an adaptive weighted fusion module evaluating the signal-to-noise ratio (SNR) of each baseband signal, and then weighting and fusing the n baseband signals using the square of the SNR as a weighting coefficient to obtain a fused signal; a dynamic temperature drift compensation module performing temperature drift compensation on the fused signal to obtain a compensated signal; and a variational mode decomposition adaptive filtering module performing adaptive filtering on the compensated signal to output the final acceleration signal. The effect is to improve the detection of ultra-low frequency weak vibrations in a MEMS accelerometer and enhance the accuracy of wide-temperature-range dynamic temperature drift compensation.

This invention discloses a differential chaotic phase-shift keying waveform design method and modulation / demodulation method suitable for integrated communication and sensing. In this invention, the reference subcarrier and data subcarrier within the same subcarrier group share the same chaotic reference sequence, allowing the receiver to recover the original data using the existing OFDM-DCSK incoherent detection structure. Simultaneously, based on the Riemann matrix-based group selection mapping method, by constructing a constant complex weight vector within the group, multiple OFDM-DCSK time-domain candidate waveforms are generated and selectively transmitted without changing the OFDM-DCSK system's "reference-data equal-weight spread spectrum" structure and the receiver's incoherent demodulation method, thus achieving effective suppression of PAPR in the transmitted waveform. Using the OFDM-DCSK time-domain candidate waveforms as a unified baseband signal, incoherent communication and radar sensing functions are simultaneously realized with a single hardware and spectrum resource.

A modulation and demodulation method, apparatus, and system are disclosed, characterized in that the method comprises the following steps: Step 1, generating a quantum step wave based on a stepped AC quantum voltage and an original carrier wave; Step 2, performing equal-interval sampling and flat-interval sampling on the quantum step wave to obtain the step distance error and flat-interval error existing between the step wave and the original carrier wave; Step 3, setting the transmission window width based on the correlation between the step distance error and the flat-interval error, and performing modulation and demodulation of the original signal based on the transmission window width. This invention has a clear concept and a simple method. By eliminating transient process data, it improves the accuracy of data demodulation and recovery processes, reducing noise while ensuring transmission efficiency.

The application discloses an affine frequency division multiplexing modulation and demodulation method, device, system, medium and product, the affine frequency division multiplexing modulation transmitting method comprises the following steps: obtaining a target frequency domain signal to be transmitted, and calculating two chirp matrices based on two chirp parameters; the target frequency domain signal is multiplied in parallel by the conjugate matrix of the second chirp matrix to obtain a target rotating frequency domain signal; the signal is inversely discrete fourier transformed to obtain a first target time domain signal; the first target time domain signal is secondly phase-rotated based on the conjugate matrix of the first chirp matrix to obtain a second target time domain signal; the target time domain signal is preprocessed before transmission to generate a target time domain transmitting signal and perform radio frequency transmission, and the technical scheme of the embodiment of the application can effectively solve the performance bottleneck problems, such as Doppler frequency shift sensitivity and weak anti-interference ability, of the orthogonal frequency division multiplexing technology in the high-speed mobile scene.

The application discloses an Ethernet carrier modulation and demodulation circuit, a laser bus controller and a system. The Ethernet carrier modulation and demodulation circuit is integrated with a double-isolation power supply and comprises a network isolation unit and a coupling modulation and demodulation unit. The network isolation unit is used for electrically isolating a first group of TX differential signals and a first group of RX differential signals to obtain a second group of TX differential signals and a second group of RX differential signals after isolation. The coupling modulation and demodulation unit is used for coupling and modulating the second group of TX differential signals and an external direct-current system power supply into active Ethernet TX carrier signals and decoupling and demodulating the second group of RX differential signals and an external direct-current driving power supply into active Ethernet RX carrier signals. Thus, the electrical wiring mode can be simplified, the power supply interference of the laser equipment is reduced, and the integration degree and the communication speed of the laser equipment are improved.

A system and a method thereof for performing modulation and demodulation based on a chirp spread band technique are disclosed. A system for performing modulation and demodulation based on a chirp spread band technique according to one embodiment of the present disclosure includes: a transmitter that transmits a chirp signal; and a receiver that receives and demodulates the chirp signal. The transmitter determines the number of data bits (M) modulated in a unit symbol based on a first residual carrier frequency offset and a spreading factor (SF), and transmits a first chirp signal obtained by modulating the first data bits in at least one symbol according to the determined number of data bits modulated in the unit symbol to the receiver. The receiver may transmit information indicating a second residual carrier frequency offset detected based on the received first chirp signal to the transmitter.

The application discloses a receiver positioning and rotation angle estimation system based on a photodiode and an LED, proposes a new light positioning method and a rotation angle estimation method, and obtains a high-precision two-dimensional positioning result for the needs of indoor positioning, robot navigation, game equipment and the like. The method collects incident light signals through a PD array, and can directly obtain two-dimensional plane coordinates and a rotation angle of the receiver through a positioning algorithm and a rotation angle estimation algorithm. Compared with existing three-dimensional indoor light positioning methods such as an angle of arrival, a time of arrival and a received signal strength, the application has the advantages that: the application does not depend on a synchronous or demodulation system; the operation complexity is low; only a PD array is needed to receive a signal; the application can provide a centimeter-level precision within a certain range; the application can directly obtain a rotation angle estimation; the application does not depend on fixed light power; and the PD array can support high-speed visible light communication.

The application discloses a full-fiber unmodulated frequency discriminator with long absorption spectrum, which is used for obtaining an error electric signal capable of indicating the relative central frequency deviation of the current output frequency of a laser, and can be applied to a laser frequency stabilization system. The frequency discriminator is based on the gas chamber absorption spectrum difference principle, and comprises a laser to be stabilized, a frequency shifter, a gas chamber, a balanced detector and a transmission optical fiber. The frequency discriminator realizes double gas absorption spectrum while saving cost and reducing the system volume through the internal optical structure design. The frequency discriminator has simple structure and is easy to integrate. The process of obtaining the error electric signal does not need modulation and demodulation, and high frequency discrimination sensitivity is realized through long absorption spectrum.

This invention relates to the field of downhole communication in oil and gas wells, and provides a 2FSK modulation and demodulation circuit for downhole communication. It comprises a 2FSK modulation circuit, a power amplifier, a transmitting transducer, a reciprocal transducer, a receiving transducer, a power supply circuit, and a 2FSK demodulation circuit. The baseband signal is processed by a comparator module, a transistor switching module, a signal conditioning module, and a VCO module in the 2FSK modulation circuit, resulting in a phase-continuous 2FSK modulated signal. This signal is then transmitted downhole via the power amplifier and the transmitting transducer. The reciprocal transducer receives the signal and transmits it to the receiving transducer. The 2FSK demodulation circuit then filters the complete signal acquired by the receiving transducer and demodulates the baseband signal. This invention's modulation and demodulation circuit achieves phase continuity of the modulated signal between adjacent symbols, has a simple circuit structure, and offers advantages such as high signal transmission stability and the ability to achieve long-distance downhole communication in oil and gas wells.

This invention belongs to the field of chip integration technology and relates to an integrated DC-DC fault handling circuit based on feedback tolerance. It includes: a DC-DC output terminal connected to the input terminal of an output control unit and a fault modulation-feedback coordination unit; an output terminal of the output control unit connected to the input terminal of the fault modulation-feedback coordination unit; an output terminal of the fault modulation-feedback coordination unit connected to the input terminal of a primary-side latch unit and the input terminal of a power transmission control unit; an output terminal of the primary-side latch unit connected to a PG signal module and the input terminal of the power transmission control unit; an output terminal of the PG signal module connected to the input terminal of a dual unlocking control unit; an output terminal of the dual unlocking control unit connected to the input terminals of the primary-side latch unit and the power transmission control unit; and an output terminal of the power transmission control unit connected to the DC-DC input terminal. The fault handling circuit of this invention provides a complete fault detection-modulation-demodulation-latch-unlocking process path, enabling fault handling.

This invention discloses a weak magnetic field signal conditioning device, comprising a high-frequency signal generation unit, a magnetoresistive full-bridge induction unit, an instrument differential amplifier unit, a secondary alternating amplifier unit, a phase-sensitive detector unit, and a filtering unit. The high-frequency signal generation unit provides a modulation signal to the magnetoresistive full-bridge induction unit and a reference signal of the same frequency and phase to the phase-sensitive detector unit. The magnetoresistive full-bridge induction unit adopts a spatially orthogonal layout, capturing a three-dimensional magnetic field vector and converting it into a differential electrical signal. The differential signal is amplified by two stages of low-noise amplification by the instrument differential amplifier unit and the secondary alternating amplifier unit, and then sent to the phase-sensitive detector unit for synchronous demodulation. Finally, the filtering unit outputs a DC or low-frequency signal reflecting the magnetic field strength. This invention, through a hardware-level modulation-demodulation architecture combined with the lock-in amplification principle, extracts nanosecond-level weak transient magnetic signals with a high signal-to-noise ratio under strong electromagnetic interference, achieving deep noise stripping and possessing advantages such as high measurement accuracy, strong adaptability, and stable reliability.

This invention discloses a satellite communication and navigation chip and a satellite communication and navigation system, belonging to the field of broadband satellite communication technology. The satellite communication and navigation chip includes: a chip body; and an RF front-end module, a first analog-to-digital / digital-to-analog converter, a shared baseband bus, a GNSS receiving module, a baseband modulation and demodulation module, and a shared module disposed on the chip body. This invention highly integrates essential satellite communication functional modules into a single chip, achieving a low-power, small-size, and highly reliable design. The satellite communication and navigation chip of this invention supports dynamic expansion of array element scale, and can implement digital beamforming and signal processing with 8, 16, or even higher array elements through FPGA, significantly improving the positioning accuracy, anti-interference capability, and broadband communication performance of the satellite communication and navigation system.

The application discloses a kind of diamond NV color center magnetic detection control method and system.Method includes scanning microwave frequency and obtaining fluorescence signal, fluorescence signal is converted into digital signal after being converted by analog-digital converter, and after being calculated by PID module, output is magnetic resonance frequency information, and magnetic resonance frequency information is used to control microwave signal generation, to realize the microwave regulation and control of fluorescence.The application adopts all-digital way integration to realize multiple independent functions in traditional control system, and uses digital signal to realize the synchronization between modulation and demodulation module, supports flexible expansion of channel number through algorithm, can realize more than 16 modulation and demodulation channels in single set of hardware resources, solves the problem that existing control system channel expansion is not flexible, hardware resources are used too much, with the advantages of small size, low power consumption, channel scalable.

This invention provides a frequency-locked laser system, including a probe light source, a frequency-output probe laser, and a frequency-doubled coupling light source to output a coupling laser. The frequency-locking module includes an electro-optic phase modulator to phase-modulate the probe laser and generate a modulated laser; a saturated absorption spectrum device receives the modulated laser and generates a saturated absorption spectrum signal, which is detected by a first photodetector; an electromagnetic induction transparent spectrum generation device receives the modulated laser and the coupling laser and generates an electromagnetic induction transparent spectrum signal, which is detected by a second photodetector; a frequency-locking controller generates a first error signal by modulating and demodulating the saturated absorption spectrum signal, which controls a first frequency modulation controller to lock the frequency of the probe light source; after the probe light source is locked, the electromagnetic induction transparent spectrum signal is modulated and demodulated to generate a second error signal, which controls a second frequency modulation controller to lock the frequency of the coupling light source. This solves the problems of complex tuning, poor stability, and large size in dual-wavelength laser systems.

This application relates to the field of smart grid technology, and in particular to a microwave-free zero-flux current measurement system based on a nitrogen-vacancy color center sensor. The microwave-free zero-flux current measurement system includes a magnetic ring, a nitrogen-vacancy color center sensor, a coil unit, a photoelectric detection module, a modulation / demodulation module, a feedback control module, and an analog-to-digital conversion acquisition module. The magnetic ring is positioned outside the conductor to be measured, and the nitrogen-vacancy color center sensor is located at the opening of the magnetic ring. The coil unit includes a bias coil, a modulation coil, and a secondary feedback coil, which are sequentially wound around the magnetic ring. The microwave-free zero-flux current measurement system completely eliminates microwave power consumption, significantly reduces sensor size, avoids low-frequency noise from the photoelectric detection circuit, and reduces the algorithmic complexity of zero-flux PID or iterative feedback control.

This invention discloses a modulator bias point control method based on a combination of dual perturbation signals: S1. Perturbation signals A and B of different frequencies and a DC bias signal are added and fused to obtain a bias voltage control signal; S2. The bias voltage control signal is applied to the bias control terminal of the modulator to control the bias point; S3. The modulator outputs a photocurrent signal reflecting optical power; S4. The photocurrent signal is converted into a voltage signal reflecting optical power through photoelectric conversion; S5. The voltage signal is gating and filtered to remove perturbation signal A, obtaining a pilot signal; S6. The pilot signal is converted into an envelope signal; S7. The envelope signal and perturbation signal A are multiplied and phase detected to output a bias point feedback AC signal; S8. The bias point feedback AC signal is conditioned into the DC bias signal in step S1. This invention employs a dual perturbation signal combination modulation and demodulation scheme, and automatically controls the bias point by detecting the phase relationship of the perturbation signals after modulation by the modulator.

This invention relates to the field of power line carrier communication and discloses a power line carrier signal processing method and system. The method includes dividing a high-speed serial data stream to be transmitted by the power line carrier into multiple parallel low-speed data streams; modulating the low-speed data streams; and demodulating the received signal. The modulation processing includes: performing OQAM preprocessing on the multiple parallel low-speed data streams; and sending the OQAM preprocessed parallel frequency domain symbols into a comprehensive filter module for processing to achieve filter bank multi-carrier modulation (i.e., FBMC modulation). The demodulation processing includes: performing FBMC demodulation on the received signal through an analysis filter module; and performing OQAM demodulation on the FBMC demodulated signal. This invention can enhance the resistance of power line communication to multipath interference and background noise, while improving the spectral efficiency of power line carrier communication.

This invention provides a communication gateway, a signal demodulation method, and a communication system. The communication gateway includes: a first communication module comprising a first microprocessor, used for demodulating analog input signals from field devices and transmitting the demodulated analog input signals to a main control module, and for modulating digital output signals and transmitting the modulated digital output signals to corresponding field devices; the main control module includes a second microprocessor, used for transmitting the demodulated analog input signals to a field switch via the second communication module, and for transmitting digital output signals to corresponding first communication modules; the main control module is connected to at least one first communication module, and each first communication module is connected to multiple field devices; this invention uses a first microprocessor to implement signal demodulation and signal modulation, replacing dedicated modulation and demodulation chips, increasing the types and total number of signals accessed by field devices, and reducing hardware costs.

The application discloses a kind of robust fast secret channel construction methods for amplitude using CSS spread spectrum modulation, mainly solve the problems, such as the limited transmission distance and capacity of secret channel in the existing low-power wide-area network environment, steps include: the modulation method design of secret channel;Signal frame structure design and frame detection;The demodulation method design of secret channel;Analysis is carried out to the information loss in the demodulation process of secret signal.The application designs the LoRa physical layer secret channel modulated by amplitude using CSS spread spectrum modulation method, designs the modulation and demodulation method of secret channel, analyzes the information loss in the demodulation process of secret signal, constructs the robust fast secret channel, widens the construction scene of secret channel, and the operation method is simple and clear, has practical value.

This invention provides a method for achieving faster end-to-end data transmission via a voice channel. It designs a modulation and demodulation scheme based on chirp signals and deep learning, solving the impact of voice activity detection technology on data transmission and significantly improving data throughput. The method includes: the sender generating a random data certificate and modulating the data-signal using a chirp-based modulation scheme; the modulated chirp signal being transmitted in the voice channel; the receiver demodulating the received signal using a deep learning-based demodulation scheme; the receiver verifying the received data using error correction codes; and both parties using a dedicated data link protocol based on stop / resume mechanisms, time synchronization, and retransmission schemes between the caller and the callee to ensure complete data reception by the receiver.

The present application relates to the technical field of detection, and more particularly to a coating machine online foreign matter detection method and device, comprising a transmitting end, a receiving end, a gantry, a glass substrate and a processing system, a laser light path is formed between the transmitting end and the receiving end to facilitate detection of 100-500 nm tiny foreign matters during coating of the coating machine; a modulated and demodulated signal is outputted to obtain a stable demodulated amplitude signal; a state machine mechanism is set to identify and shield non-detection sections, thereby reducing edge false positives and motion false positives; a dynamic baseline and a relative ratio are used to determine the signal, and updating of the dynamic baseline is realized according to a first-order low-pass filter; a time window is combined to suppress transient noise caused by vibration and to determine foreign matters; and coordinates of the tiny foreign matters are outputted. The present application has the advantages of improving the detection capability for tiny foreign matters and reducing occurrence of foreign matter missed detection or false positive events.

A communication system based on DOCSIS protocol includes a server for sending signals and demodulating received signals; a coaxial cable for transmitting the signals sent and received by the server through a coaxial cable network; a frequency divider connected to the coaxial cable for dividing the signals sent by the server into downstream signals and full duplex signals; a downstream communication path for transmitting the downstream signals sent by the server to a first modem unit; an upstream communication path for transmitting upstream signals sent by a second modem unit to the server; a full duplex communication path for simultaneously transmitting the downstream signals divided by the frequency divider and the upstream signals sent by the second modem unit, and for separating the downstream signals from the full duplex signals and transmitting the downstream signals to the first modem unit, and for transmitting the upstream signals sent by the second modem unit to the server, realizing in-band multiplexing of upstream and downstream signals and improving the transmission speed of the upstream and downstream signals.