18 results about "Pulse-position modulation" patented technology

The invention discloses an efficient soft demodulation method and system suitable for pulse position modulation, and relates to the technical field of laser communication. Pulse position modulation signals and preset channel parameters are received, and time slot receiving signals are acquired based on the pulse position modulation signals, the preset channel parameters comprise the optical signal intensity and noise power of a Gaussian channel, the pulse optical signal electron number of a Poisson channel and the electron number of an ambient optical signal; inputting the time slot receiving signal and a preset channel parameter into a pre-established soft demodulation model based on a maximum posteriori and a maximum likelihood criterion, and outputting to obtain a log likelihood ratio LLR of a modulation bit; meanwhile, the index logarithm operation of the LLR is simplified by adopting a max-log method, and the calculation complexity is reduced; aI is adopted to optimize the scaling coefficient for the performance loss caused by soft demodulation calculation simplification to balance the performance loss and the implementation complexity, so that the transmission efficiency of PPM modulation is improved.

The invention discloses a free space optical communication and sensing integrated system based on intensity modulation direct detection and time domain cross-correlation, and belongs to the field of optical communication, the system adopts an intensity modulation direct detection architecture, a transmitter uses a differential pulse position modulation signal, a DPIM signal is loaded to an optical carrier through a Mach-Zehnder modulator, and the DPIM signal is transmitted to the optical carrier through the Mach-Zehnder modulator; shaping the light beam and coupling the light beam into a free space; and the receiver couples the spatial optical signal into the optical fiber and demodulates the spatial optical signal after photoelectric conversion, so that a communication function is realized. And the transmitter receives the echo optical signal reflected by the receiver, performs analog-to-digital conversion on the echo optical signal, and then obtains the time delay of the echo signal compared with the transmitting signal by combining with a time domain cross-correlation algorithm, thereby obtaining the distance information of the two communication parties. According to the system, the radar ranging function is seamlessly integrated into a free space optical communication system, the communication and ranging functions can be simultaneously realized without additional hardware, the two functions can be simultaneously performed without mutual interference, and the system has the advantages of simple structure, low cost and high ranging precision.

The application discloses a kind of multistage separation integrated processing method and device, for the process synergy of existing technology is poor, separation efficiency is low, and secondary emulsification is prone to occur and so on, the application is controlled by PLC system coordination, in turn, filtering, heating, coupling enhanced separation, chaotic electric field dehydration, vacuum circulation separation and multi-gradient fine filter processing are carried out.Coupling enhanced separation unit combines electric field pre-separation and cyclone centrifugal enhanced separation;Chaotic electric field dehydration unit uses pulse position modulation electric field to destroy emulsion interface;Vacuum circulation separation unit realizes depth purification under negative pressure environment.The scheme realizes the step-by-step efficient removal of different particle size impurities in industrial waste oil, and the quality of regenerated oil is significantly improved, and the energy consumption of the system is greatly reduced.The device adopts modular design, and each unit is intelligently coordinated, with high processing efficiency, strong adaptability, stable operation and other advantages, providing reliable technical support for industrial waste oil resource utilization.

The invention provides a flight control signal decoding method and an unmanned aerial vehicle flight attitude adjusting method thereof, and relates to the technical field of unmanned aerial vehicles. The decoding method comprises the following steps: acquiring a pulse position modulation signal of a plurality of flight control instructions containing multiple channels, wherein the pulse position modulation signal represents the relationship between the pulse time interval of each channel and the corresponding flight control instruction; the pulse position modulation signal is detected, under the condition that the rising edge of the pulse position modulation signal is detected and triggering is interrupted, the counting result of a preset timer at the current moment is obtained, and the rising edge represents the critical moment when the level of the pulse position modulation signal jumps from the low level state to the high level state; determining a pulse period of each channel in the pulse position modulation signal based on a counting result of the timer; and decoding the pulse position modulation signal according to the pulse period to obtain a plurality of flight control signals corresponding to the plurality of channels.

The application discloses a kind of bionic concealed underwater acoustic communication detection integrated method.Existing method does not consider the concealment of communication and detection jointly.The method of the present application first extracts click sound signal and whistle signal, and carries out power and correlation screening;Then the original click sound signal is waveform encoded and pulse position modulated, and the original whistle signal is time-frequency shape encoded and waveform parameter modulated.Using the good detection performance of bionic modulated signal, generate bionic communication detection integrated signal.In echo signal receiving end, different echo signal processing method is used.In communication receiving end, combined demodulation method is used.The bionic whistle signal generated by the present application has high similarity with the original signal in time domain, and the time-frequency profile is continuous.The present application can improve the communication rate by sampling combined modulation, has good concealment, not only can realize the accurate estimation of target distance, speed and azimuth, but also has good communication performance.

The application discloses a torque sensor, comprising: a middle shaft; a shaft sleeve assembly fixed to the outer periphery of the middle shaft; the shaft sleeve assembly comprises a shaft sleeve body, a first control board and a first coil, the first control board and the first coil are both mounted on the shaft sleeve body; a disc claw assembly is sleeved on the periphery of the middle shaft and is in transmission connection with the middle shaft, the disc claw assembly comprises a strain gauge, a second control board and a second coil; wherein the second control board is configured to generate a pulse position modulation signal after digitally encoding the voltage signal output by the strain gauge; the duty cycle of each symbol in the pulse position modulation signal is not greater than 1 / 3; the first control board is configured to receive the pulse position modulation signal and output torque information after decoding. The torque sensor has low cost and high precision. In addition, the disc claw assembly and the shaft sleeve assembly can be arbitrarily matched, thereby improving the manufacturability and maintainability.

The invention discloses a semiconductor wafer factory carrying equipment communication method based on infrared light. The method comprises the following steps: establishing a non-contact communication link between process equipment and carrying equipment through an infrared light signal; mapping the IO signal into infrared pulse positions in different time slots by adopting pulse position modulation; non-contact communication link fault tolerance is realized through dual-channel redundancy; time sequence synchronization of the process equipment and the carrying equipment is realized by sending a timestamp synchronization frame; the communication quality is guaranteed through dynamic power adjustment and an error retransmission mechanism; and when the control instruction is transmitted, closed-loop confirmation is completed through safety interlocking logic. State interaction and control instruction transmission between the semiconductor equipment and the OHT are achieved by modulating infrared light signals, the problems of abrasion, pollution, high alignment precision requirement and the like existing in traditional physical contact type IO communication are solved, and the method is suitable for a semiconductor wafer factory automatic transportation system with high cleanliness and high reliability.

The application discloses a kind of laser communication and laser imaging integrated system, including transmitting end and receiving end;The transmitting end includes the communication signal modulation unit, pulse laser source and transmitting optical path connected in sequence;The receiving end includes receiving optical path, photoelectric detector, amplification circuit, signal acquisition unit, communication signal demodulation unit and image reconstruction unit;The laser communication and laser correlation imaging mode based on pulse position modulation are used in the application, laser communication and laser imaging system can be realized in sharing hardware resources, function is relatively independent, not dependent on each other, and system performance is not sacrificed.At the same time, two systems can work independently also can work simultaneously to realize the effect of "visual communication".

This invention discloses a bidirectional communication ranging method based on a room-temperature single-photon detector, belonging to the field of laser communication and ranging technology. The method employs a serial concatenated pulse position modulation coding and bidirectional asynchronous response ranging mechanism, designing a dedicated frame structure including a frame synchronization header, time information, and communication data. The proportion of ranging frames is controlled within the communication bandwidth, achieving integrated communication and ranging functions. At the receiving end, a coarse-fine concatenated time slot synchronization method is used: first, coarse synchronization is achieved by recovering the time slot clock through matched filtering; then, fine synchronization is achieved by compensating for residual time slot offsets based on a maximum likelihood estimation algorithm, significantly improving time slot synchronization accuracy. This invention, operating under room-temperature single-photon detector conditions, eliminates the need for cryogenic cooling equipment, effectively solving the problem of balancing communication rate and ranging accuracy. It significantly improves ranging accuracy and system stability, and is suitable for scenarios sensitive to size and power consumption, such as inter-satellite links and underwater communication.

This invention discloses a laser-induced acoustic underwater communication method and apparatus based on discrete linear frequency modulated pulse intervals, belonging to the field of cross-medium communication technology. The invention first maps the binary data to be transmitted into a pulse time interval pattern, where logic "0" and "1" correspond to pulse sequences with pulse intervals that decrease or increase linearly with time, respectively, and inserts a silence protection interval. A laser is controlled to emit pulses towards the water surface at non-uniform intervals, utilizing the photoacoustic effect to excite a train of acoustic pulses with discrete linear frequency modulated characteristics in the water. After acquiring the acoustic signal, the receiving end uses a local reference signal matching the transmitting end's pattern to perform dual-channel cross-correlation demodulation, achieving data decision-making and self-synchronization based on the amplitude and position of the correlation peaks. This invention combines the cross-medium advantages of laser-induced acoustics with the high processing gain characteristics of linear frequency modulated signals, solving the problem of poor multipath resistance in traditional pulse position modulation and significantly improving communication reliability in complex underwater acoustic channels.

The invention discloses a signal demodulation method, circuit and device, a storage medium and electronic equipment. Relates to the field of signal processing, and the method comprises the steps: obtaining a to-be-demodulated input signal, the input signal employing pulse position modulation; performing comparison processing on the input signal and the delay signal of the input signal through a first comparator to obtain a pulse position modulation signal; comparing the input signal with a reference level through a second comparator to obtain a signal triggering moment level; and under the condition that the level meets the triggering condition at the signal triggering moment, the pulse position modulation signal is demodulated through the single chip microcomputer. According to the invention, the problem that the signal demodulation cost is high when preprocessing of signal demodulation is carried out based on an FPGA chip in the prior art is solved.

The application discloses a chaotic communication and sensing integrated signal processing method and device and a communication system. The scheme provided by the application divides an information bit sequence into a modulation bit sequence, an index bit sequence and a PPM bit sequence, processes an initial signal vector by combining a pulse position modulation technology, optimizes spectral utilization by double control of the modulation bit and the index bit, segments the initial modulation signal according to PPM orders and generates a signal vector, and offsets the signal vector in the time domain by combining a shift matrix. The scheme utilizes the good autocorrelation characteristics and the low cross-correlation characteristics of an LFM signal, and on the basis of the original DCSK-LFM modulation mode, combines pulse position modulation and index modulation, so that the same carrier can carry more information, thereby improving the transmission rate when applied to a JRC system and the overall performance of the communication system.

The invention discloses a pulse modulation system and method based on a neural network, and the method comprises the steps: firstly processing an input symbol bit stream through a pulse position modulation module, extracting a position-related symbol bit through an MLP, converting the position-related symbol bit into a normalized current value, and transmitting the normalized current value into a pulse neural network; controlling the occurrence time of a pulse time domain and outputting a pulse position vector by utilizing a membrane potential accumulation characteristic and a time-varying discharge threshold value of linear decline in a symbol period; extracting phase correlation symbol bits through a pulse phase modulation module, distributing the phase correlation symbol bits to positive and negative parallel channels, adjusting the phase based on a pulse position vector, and generating a pulse vector with position and phase characteristics; and finally, expanding the discrete vector into a continuous time domain pulse signal by a transposed convolutional layer. According to the invention, the limitation of hardware adaptability and expansibility of a traditional pulse modulation system is overcome, and an efficient and flexible scheme compatible with various pulse modulation variants is provided for the field of Internet of Things and wireless communication.

The invention relates to a millimeter wave pulse signal modulation method, which relates to the technical field of pulse signal modulation, and comprises the following steps: carrying out adaptive bit width serial-parallel conversion, coding, verification and encryption preprocessing on a digital baseband signal to generate a baseband modulation signal meeting millimeter wave transmission requirements; a millimeter wave carrier is generated, and high-precision frequency stabilization and amplitude-phase calibration are completed; a pulse signal frame structure is constructed, and framing packaging of the baseband modulation signal is completed; pulse amplitude and pulse position modulation are fused to complete millimeter wave pulse modulation; step-by-step power amplification is carried out on the modulation signals, and harmonic components are filtered out; shaping, filtering and optimizing a frequency spectrum for the amplified signal; signal parameters are collected and dynamically calibrated, and modulation signals meeting the millimeter wave pilot frequency duplex transmission standard are generated. According to the invention, full-flow optimization of millimeter wave pulse signal modulation is realized, baseband signal processing safety and carrier stability are improved, modulation signal quality and multi-beam transmission balance are optimized, and the method is adaptive to various application scenarios of millimeter wave high-speed broadband communication.

A backscatter radio system having a transceiver module and a transponder. The transceiver module is configured to generate and transmit a radio frequency pulse signal with Pulse Position Modulation (PPM). The generated radio frequency pulse signal includes a power and information transferring pulse and a time reference pulse within a dual symbol duration comprising a first and a second symbol periods. The power and information transferring pulse enables a power injection to a rectifier circuit in the transponder and the time reference pulse enables an excitation of a resonance signal in a resonance circuit in the transponder. A response radio frequency pulse signal with PPM is generated using the resonance signal generated in the resonance circuit with a time offset such that the first and second symbol periods are separated in the time domain.

The invention relates to a method for eliminating distance measurement ambiguity of a long-distance laser radar and a laser radar system, and belongs to the technical field of laser radars. The invention provides a pulse position modulation method and an echo signal processing algorithm, and provides a pulse position modulation type laser radar system realized on the basis of the method for eliminating the ranging ambiguity of the high-repetition-frequency long-distance laser radar. Based on the method for eliminating the ranging ambiguity of the high-repetition-frequency long-distance laser radar, the ranging ambiguity problem in the long-distance and high-repetition-frequency imaging laser radar can be effectively eliminated under the condition that no hardware is added, the original short pulse characteristic is ensured, the imaging capability is improved, and the cost is saved. Particularly, technicians in the field can clearly find that the method is not only suitable for pulse imaging, but also has good reference significance for phase ranging and single-photon imaging radar.

The invention provides a modulation decoder supporting multiple modulation systems. An input buffer module receives and caches input soft bit data; the control state machine module generates a data request signal and controls the reading time sequence of the soft bit data; the branch metric calculation module selects a corresponding multiplication matrix according to a preset modulation mode and performs operation with the soft bit data to obtain a branch metric value; the addition, comparison and selection module is used for generating survivor paths and current path metrics; the path metric calculation module obtains the maximum path metric and the corresponding state index; the surviving path storage module stores surviving paths; the backtracking module generates a decoded bitstream. The decoder supports multiple modulation systems such as binary phase shift keying modulation, binary phase shift keying-pulse position modulation and mapping modulation, the processing bandwidth is larger than or equal to the input data bandwidth by configuring the depth of the input buffer module and the sliding window technology, new data can be continuously received in the backtracking process, and the decoding efficiency is improved. And the decoding efficiency and the system adaptability are improved.

The application discloses a method, system, device and medium for wireless communication, and relates to the field of wireless communication. The method comprises the following steps: obtaining data to be sent and packing the data into a network data frame; performing multi-pulse position modulation on the network data frame to obtain a plurality of pulse signals; and sending the pulse signals to a receiving end through a plurality of lasers, so that the receiving end demodulates the pulse signals and receives the data to be sent. Compared with the previous method of obtaining a single pulse signal through single-pulse position modulation and sending the single pulse signal through a single laser, the method provided in the application obtains a plurality of pulse signals through multi-pulse position modulation at a data sending end, and sends the pulse signals through a plurality of lasers, so that the data to be transmitted is relatively increased, the time required for completing a certain amount of data transmission is reduced, the data transmission efficiency is greatly improved, and the anti-interference capability is relatively enhanced.