32 results about "Demodulation" patented technology

A master unit and a remote unit is provided for a multiband transmission system for distributing and combining signals of at least one wireless communication network and at least one digital network. A reference frequency generator is arranged in the master unit, the reference frequency generator being designed to clock a master modem for converting the signals of the at least one digital network. The reference frequency signal emitted by the reference frequency signal is restored via a reference frequency receiver and is used for closing a remote modem that is located there for demodulation.

The invention provides a power line carrier communication terminal device which comprises a power line carrier power adapter system used for allowing a strong-current power supply to be subjected to voltage reduction processing for outputting a low-voltage power supply, a signal modulation-demodulation system used for modulating/demodulating signals, and a signal transmission device used for transmitting low-voltage power supply and power line carrier signal, wherein the power output interface of the power line carrier power adapter system is connected with the power input interface of the signal modulation-demodulation system through the signal transmission device, so as to supply low-voltage direct current supply; and the power line carrier signal transmission interface of the power line carrier power adapter system is connected with the power line carrier signal transmission interface of the signal modulation-demodulation system through the signal transmission device, so as to realize the power line carrier signal communication. The device provided by the invention solves the electric safety problem, has an integrally reduced size and brings convenience for integration.

The invention discloses a baseband receiving method and a baseband device applied to a terminal in a narrow-band wireless system, and relates to wireless communication technology. The baseband receiving method includes the steps: calculating LS (least squares) estimation values of an NRS (numeric rating scale) pilot frequency position, averaging LS results of the same subcarrier position in a subframe, and encrypting LS results of different carrier positions to obtain a list of results; calculating frequency domain correlation values, and distinguishing different gears of the correlation values. The list of encrypted LS results are filtered according to the distinguished gears, filter results serve as channel estimation values of all OFDM (orthogonal frequency division multiplexing) symbols on the subframe, noise power values are estimated according to the encrypted LS results, and finally, received signals are subjected to MIMO (multiple input multiple output) detection and demodulation according to the channel estimation values and the noise power estimation values. Compared with the prior art, the baseband receiving method has the advantages that the calculating amount of the baseband receiving process can be greatly reduced, the method is suitable for the narrow-band wireless system with low signal-to-noise ratio and low movability, and good receiving performance is achieved.

The invention provides a power line carrier modulation method, a demodulation method, a circuit and a chip. The modulation method comprises the following steps of: detecting narrow-band nongaussian noise frequency in a power line; selecting non-noise frequency from a preset carrier frequency band as modulation carrier frequency; generating a modulation carrier according to the modulation carrier frequency; modulating a digital signal to be modulated to the modulation carrier to generate a power line carrier signal. By using the modulation method, the narrow-band nongaussian noise frequency can be avoided, the change of noise environment of the power line can be adapted, and the quality of power line communication can be improved.

An information transmission system is broken down into a sound recorder, a transmission medium and a sound reproducer; a digital audio signal is produced from MIDI music data words through any kind of modulation technique such as, for example, Y-modulation technique, P-modulation technique or Q-modulation technique, and the digital audio signal is transferred from the sound recorder through the transmission medium such as a magneto-optic disc, a wire communication network or the free space to the sound reproducer, when the digital audio signal reaches the sound reproducer, the sound reproducer analyzes the digital audio signal to see what modulation technique was employed to produce it, and demodulates the digital audio signal through an appropriate demodulation technique, thereby permitting user to employ any sound recorder to produce the digital audio signal.

The invention discloses a system and a method for monitoring a dynamic disaster of a coal mine with fiber bragg gratings. According to the system and the method, the fiber bragg gratings (1) are distributed in or on the surface of rod bodies of anchor rods (2); the anchor robs (2) are inserted into two uppers of a roadway of the coal mine or other effective positions by drilling holes; and optical connector (11) capable of being connected with the external are introduced from the tails of the anchor rods (2), and connected with fiber bragg grating network demodulation instruments (5) which are connected to a testing computer (6) to form a testing system for monitoring the dynamic strain. With the adoption of the system and the method disclosed by the invention, the dynamic disaster can be relatively accurately forecasted, and relatively high performance of preventing outside interference can be achieved; and the method is an intrinsic safety testing method.

The invention discloses a method for GPU-based (Graphics Processing Unit) object three-dimensional shape measurement, and belongs to the technical field of object three-dimensional measurement. The method particularly comprises the following steps: projecting structure grating to the surface of an object to be measured by a projector; shooting the surface of the object to be measured by two cameras simultaneously to obtain two groups of image sequences; storing the two groups of image sequences into computer memory; completing distortion correction, phase demodulation, corresponding points matching and three-dimensional reconstruction for the image by a GPU in parallel; transmitting the object three-dimensional coordinate obtained through three-dimensional reconstruction to the computer memory by the GPU; repeating the above steps until the measurement is complete, and releasing the GPU and the storing space. The method adopts multi-core GPU to realize the parallel calculation at thread level, greatly increases data processing speed, and can satisfy the real-time requirement for three-dimensional measurement of a dynamic object.

The invention provides an uplink system of a subcarrier multiplexing optical network of filter based multicarrier modulation. The system comprises access control modules, filter based multicarrier modulation modules, subcarrier modulation modules, a multiplexing module, a feed line type fiber, a de-multiplexing module, photoelectric detectors, subcarrier demodulation modules and uplink data reception modules that are successively connected. Data generated by the access control modules is modulated in the filter based multicarrier modulation method, modulated user data is modulated to different optical subcarriers and transmitted via RF subcarrier modulation of optical carrier waves, and data from different units is multiplexed to uplink fiber channels. Filter based multicarrier modulation technology is combined with subcarrier multiplexing technology so that frequency spectrum resources of uplinks are utilized in high efficiency, interference among symbols and subcarriers of uplink users can be effectively resisted, and higher transmission speed and frequency spectrum frequency can be supported.

Embodiments of the invention provide a discovery method of a neighbor node and an apparatus thereof. The discovery method comprises the following steps that each node in a wireless self-organized network generates an only pseudo random sequence based on a node identification and generates measurement matrixes formed by the pseudo random sequence and a pseudo random sequence generated based on other node identification; each node broadcasts the pseudo random sequence of the node to other nodes in a network and simultaneously each node receives a superposed signal formed through superposing the pseudo random sequences sent by the other nodes; based on the measurement matrixes, the superposed signal is demodulated, and according to a demodulation result, identification information of the neighbor node is acquired. Through the method and the apparatus, a data conflict and half-duplex limitation can be avoided; and a neighbor discovery process of the nodes in the wireless self-organized network can be completed in one time slot so that neighbor node discovery time is greatly reduced; and in addition, high accuracy is possessed.

A method of transmitting demodulation reference signals (DMRS) over one, three or five resource blocks (RBs) with Interleaved Frequency Division Multiple Access (IFDMA) from a wireless device to a wireless network node in a wireless network wherein Single Carrier Frequency Division Multiple Access (SC-OFDMA) is deployed in uplink, is provided. At least one of: a set of base sequences including thirty quadrature phase shifting keying, QPSK, sequences of length 6, 18 or 30 is determined, a demodulation reference signal sequence is derived from the determined set of base sequences, the demodulation reference signal sequence is multiplexed, and the multiplexed demodulation reference signal sequence is transmitted, by the wireless device, to the wireless network node.

Methods and apparatuses disclosed herein enable the use of Demodulation Reference Signal, DMRS, sequences that are numbered relative to an overall system bandwidth (30), while simultaneously enablingwireless communication devices (12) to determine the DRMS sequence elements mapped to their scheduled bandwidths (36) within the system bandwidth (30). Advantageously, the wireless communication devices (12) need not know the system bandwidth (30), or even be aware of where their scheduled bandwidths (36) reside within the system bandwidth (30).

The invention discloses an adaptive threshold adjusting method for a non-contact intelligent card demodulation system. An additionally-arranged adaptive threshold adjusting circuit in a non-contact IC card is utilized for accomplishment. The adaptive threshold adjusting circuit determines whether a threshold is appropriate according to the number of zeros in a zero number counter. After stabilization of a power-on simulation front end circuit, adjustment is carried out from a greatest threshold downwards, the great number of the zeros means that the threshold is too great, burr generation occurs, a fixed threshold step length is subtracted from a present threshold, after accomplishment of threshold switching of the simulation circuit, next determination is carried out continuously, till the number of the zeros reaches a prescribed range, the threshold reaches an optimum one, or demodulation for a smallest threshold is carried out. According to the adaptive threshold adjusting method, in a field intensity range of 1.5A/m-7.5A/m, for multiple antenna waveforms prescribed in an ISO/IEC14443TypeA protocol, a comparator threshold can be automatically selected, and demodulation data with pause width close to 3mus is outputted.

The invention discloses a power line carrier communication apparatus used for overocean communication. The apparatus comprises a carrier transmitting terminal, a carrier receiving terminal and a neutral buoyancy cable. The carrier transmitting terminal emits a carrier signal and the carrier signal is transmitted to the carrier receiving terminal through the neutral buoyancy cable so as to be received. The carrier transmitting terminal comprises an upper computer serial interface, a master control chip, a power line carrier modulation module, an emission coupling circuit and a coupling transformer. The carrier receiving terminal comprises the upper computer serial interface, the master control chip, the power line carrier demodulation module, a receiving coupling circuit and a decoupling transformer. The neutral buoyancy cable is a light-buoyancy-material counter-weight coaxial cable. In the invention, during communication, a special communication cable is not added so that engineering cost and construction difficulty are greatly reduced; multichannel coupling is used so as to reach a high parallel communication rate; independent coupling and decoupling circuits of each channel guarantee effective modulation and demodulation of each independent channel carrier wave; and the special coaxial cable is used so that communication reliability is increased.

The invention belongs to the technical field of in-situ tests of civil engineering, and relates to a method for jointly testing the horizontal displacement of a pile head and the stress of a pile body of a preformed pile. First, self-compensating fiber grating strain sensor strings are placed in a to-be-tested pile and are sealed by using structural adhesives, after two days of maintenance, a spherical hinged support, a load sensor, a jack and a steel plate cushion block are put in sequence between the to-be-tested pile and an engineering pile, and then first perforated angle steel and second perforated angle steel are fixed; afterwards, a first datum line beam and a second datum line beam are put up, first dial indicators and second dial indicators are mounted respectively, the self-compensating fiber grating strain sensor strings are connected with a fiber grating sensor demodulation instrument, the load sensor is connected with a load sensor display instrument; after the mounting is completed, a load test is carried out on the to-be-tested pile, and corresponding displacement and strain change values are recorded. The method for jointly testing the horizontal displacement of the pile head and the stress of the pile body of the preformed pile is simple in process, convenient to operate, low in cost, high in testing precision and high in operability; obtained numerical results are direct, high in precision and small in error.

The invention provides an MSK signal demodulation method and system based on pre-decision. The method includes the following steps: obtaining a pre-decision result of an MSK signal to be demodulated;screening multiple local template signals according to the pre-decision result; and obtaining a final decision result of the MSK signal to be demodulated based on the screened multiple local templatesignals. According to the MSK signal demodulation method and system based on pre-decision provided by the invention, through the steps of performing pre-decision on the MSK signal, selecting the appropriate local template signals according to the pre-decision result, and demodulating the MSK signal based on a multi-symbol differential detection algorithm, the bit error rate performance can be improved, the resource occupancy of multi-symbol differential detection can be reduced, and the complexity of the system can be reduced.

The invention discloses a novel optical cable sensing system for pipeline leakage detection and belongs to the technical field of monitoring. The novel optical cable sensing system is mainly used forautomatic real-time detection on leakage of liquid or gas in a pipeline. A sensing ring surrounds the periphery of the pipeline and is connected with an elastic plate below the pipeline through a connecting belt; and a sensing optical cable is paved on the elastic plate. An impact vibration signal generated when liquid or gas leaks is detected by the sensing ring and transmitted to the sensing optical cable on the elastic plate; the vibration signal modulates a laser signal in the sensing optical cable, the laser signal is sent back to a signal analysis and recognition computer system in a monitoring room through the optical cable, the specific position and the signal type of leakage are worked out through the demodulation algorithm, a monitoring staff is helped to precisely judge the failure in real time and carry out corresponding timely emergency maintenance. The novel optical cable sensing system can realize full-automatic real-time detection on leakage of the long-distance pipeline, can effectively replace traditional manual inspection tour and is simple and convenient in operation, high in economic benefit and wide in application prospect.

The invention provides a communication method and system based on a sound wave transmitting and receiving terminal. The method comprises the steps that a first terminal enables the first frequency information of a receivable sound wave to be modulated and added to a first group of sound waves with at least two frequencies and then to be transmitted; a second terminal carries out the demodulation of the first group of sound waves through employing a preset specific second frequency; The first terminal enables the first frequency information to be modulated and added to a second group of sound weaves for transmission if the information of a first type and the first frequency information are not obtained through demodulation, wherein the second group of sound waves have at least two frequencies different from the frequencies of the first group of sound waves; and the first and second terminals carries out communication with each other through the first and second frequencies if the information of the first type and the first frequency information are obtained through demodulation. Through the above mode, the method and system enable the communication terminals based on the sound waves to achieve automatic matching of sound wave frequencies, improve the compatibility of data transmission between communication terminals, and improve the success rate of communication data transmission.

The invention discloses a large-gradient free hook face measurement method. The method comprises the following steps that: applying a certain angle to a free hook face to be measured to finish the spatial frequency modulation of a free curve diffraction object light wave, and collecting by an image sensor; regulating a plurality of angles, recording multiple frames of holograms of which the free hook faces have different angles, then, through an image processing algorithm, finishing selecting the stripe sparse subarea of each frame of hologram, and recovering the subarea three-dimensional structure of the modulated free hook face to be measured through a digital reconstruction algorithm; and finally, according to a demodulation algorithm, recovering the subarea three-dimensional structureof the original free hook face to be measured, utilizing a proper stitching algorithm to realize the wavefront data fitting of multiple frames of subareas, and therefore, recovering the three-dimensional surface shape information of the free hook face. Through the introduction of an inclination angle, the collection process of free hook face high-frequency information is realized, and a new solution is provided for free hook face measurement.

The invention relates to an antiferromagnetic resonance radio frequency identification ticket management terminal. The antiferromagnetic resonance radio frequency identification ticket management terminal comprises a control unit, a modulation circuit, a power amplifying circuit, a frequency generating circuit, a demodulation circuit, a signal amplifying circuit and a radio frequency antenna circuit. Compared with the prior art, the antiferromagnetic resonance radio frequency identification ticket management terminal has the advantages that first, perfect combination of anti-fake material, digital signals and instrument identification rather than a single-manner anti-fake method is achieved on the basis of the antiferromagnetic resonance radio frequency identification technology; second, the antiferromagnetic resonance radio frequency identification material cannot be simulated; third, signal extraction is diverse, several sets of antiferromagnetic resonance effects are extracted, several parameters of an antiferromagnetic resonance radio frequency identification characteristic curve are selected, and the signals can be processed safely and flexibly;fourth, information can be read in a flexibly changing mode; fifth, the recovery scheme for the system can be restored fast after an accident happens, a same label and the system continue to be used, only an identifier needs to be tuned, the identifier can read more antiferromagnetic resonance radio frequency identification signals after being tuned, speed is high and cost is very low.

In a high frequency receiver main body 40, on a circuit board 12 within a shield case 9 with a bottom, distributors 3a and 3b, and filter circuits 4a and 4b, AGC amplification circuits 5a and 5b, mixers 6a and 6b, local oscillation circuits 8a and 8b, and demodulation circuits 15a and 15b for processing RF signals are provided. The inside of the shield case 9 is partitioned by a partition member 41 into six regions, and sealed with a shield lid. Input connectors 1a and 1b are attached to a first side surface of the shield case 9. An output connector 7a outputting an RF signal distributed by the distributor 3a is attached to a second side surface thereof. An output connector 7b outputting an RF signal distributed by the distributor 3b is attached to a third side surface thereof.

The invention relates to the technical field of channel monitoring, in particular to a channel monitoring method, a demodulation method, device, equipment and a storage medium. According to the invention, a sample signal transmitted in a channel is collected, frequency reduction processing is carried out on the sample signal by applying a linear optical sampling algorithm, the sample signal after frequency reduction is input into a hardware circuit, and the hardware circuit processes the sample signal after frequency reduction to obtain an output result for the sample signal after frequency reduction, and the performance of the channel can be obtained according to the output result. According to the invention, frequency reduction is carried out on the sample signal firstly, so that the sample signal after frequency reduction is matched with the bandwidth of the hardware circuit, thereby avoiding distortion of the sample signal caused by mismatching of the bandwidth of the hardware circuit and the frequency of the sample signal, and improving the accuracy of the obtained channel performance.

The invention provides a quasi-coherent pulse ultra-wideband receiver. The received radio frequency signal is decomposed into two paths of orthogonal signals after being down-converted into low and intermediate frequencies; therefore, even if the quality of the radio frequency local oscillation signal is not high, the influence of the frequency error can be eliminated after the two paths of orthogonal signals are subjected to square addition; the demodulation performance of the quasi-coherent pulse ultra-wideband receiver is not sensitive to a phase error and a frequency error between a radio frequency signal and a radio frequency local oscillation signal. According to the invention, a high-quality radio frequency local oscillation signal is not needed, a high-precision frequency synthesizer and a high-speed analog-digital converter are not needed, and the equipment is suitable for a low-power-consumption application scene. In addition, the capability of resisting non-ideal factors such as narrow-band interference is high. The invention further provides a signal demodulation method which is applied to the quasi-coherent pulse ultra-wideband receiver.

The invention discloses a dual-mode communication network based on a power line carrier and wireless communication. The dual-mode communication networkincludes a control module, the control module is electrically connected with a power line communication module and a wireless communication module, the control module is electrically connected with a driving module, the driving module is electrically connected with a carrier generator, and the carrier generator is electrically connected with the power line communication module and the wireless communication module. The control module is electrically connected with a mode converter. The mode converter is electrically connected with the power line communication module and the wireless communication module. A channel processing block, an OFDM demodulation module, a frame rate detection module and a filtering processing module are arranged in a dual-mode communication network of power line carrier and wireless communication, data information in the communication process is effectively processed and adjusted, and accuracy and stability can be kept when the data information is transmitted.

The object of the present invention is to realize minaturization and low cost of a diversity device for receiving digital television broadcast. In a vehicle-mounted terrestrial digital receiver, each tuner (2a to 2d) is located in a tuner-side casing (26) of a connector circuit section (25) provided at a power feeding point of a corresponding one of a plurality of digital-television-broadcast-receiving antenna devices (1a to 1d). Output terminals of the tuners (2a to 2d) are connected to a demodulation-system-side casing (10) using balanced signal cables (12a to 12d). The demodulation-system-side casing (10) contains OFDM demodulators (5a to 5d) that decode IF signals output from the corresponding tuners (2a to 2d), combining units (6a to 6c) that combine demodulated signals to generate a combined signal, and an MPEG decoder (7) that decodes the combined signal.

The invention provides a method for demodulating a TCM-CPM signal under a multipath channel. The method comprises the implementation steps that a TCM-CPM modulator modulates a binary sequence, a frequency offset estimator performs frequency offset compensation on a modulation signal, a demodulator performs first viterbi demodulation on a frequency offset compensation signal, and then the demodulator performs second viterbi demodulation on the frequency offset compensation signal. In the second Viterbi demodulation branch metric calculation process, the demodulated code element, the current demodulation code element and the modulation signal corresponding to the first demodulation result serve as reference signals to be subjected to convolution with the channel gain value, the influence of multipath interference on the demodulation result can be restrained to the maximum extent, and the bit error rate is effectively reduced.