51results about How to "Fast demodulation" patented technology

The invention discloses a method for MSK iterative demodulation by combining an LDPC code, which comprises the following steps of: performing orthogonal down-conversion, low-pass filtering, carrier frequency offset rough estimation and compensation on received signals in turn, then storing processing results in a first-stage buffer, and simultaneously performing differential demodulation on data after compensation; performing frame synchronization head-related detection on the data after the differential demodulation, and after a frame synchronization head is detected in the related detection, using a control switch to perform carrier phase offset rough estimation and compensation and simultaneously perform an SNR estimation on the data in the first-stage buffer; storing the data after the carrier phase offset compensation into a second-stage buffer; and reading the data in the second-stage buffer to perform LDPC code assisted iterative carrier and timing synchronization and compensation, performing MSK coherent demodulation and LDPC encoding on the data after the LDPC code assisted iterative carrier and timing synchronization and compensation in turn, and outputting an encoding result decision. The technical scheme provided by the invention realizes quick demodulation and encoding functions under ultra-low SNR by using the system and the method for the MSK iterative demodulation by combining the LDPC code.

Disclosed herein is a signal processing apparatus, including: a computation device operable to perform transform computation adapted to Fourier-transform a time domain OFDM i.e., Orthogonal Frequency Division Multiplexing signal into a frequency domain OFDM signal; a processing device operable to perform carrier frequency offset detection adapted to detect an estimated carrier frequency offset that is an error of a carrier used for demodulation of the OFDM signal; and a carrier frequency offset correction device operable to perform carrier frequency offset correction adapted to correct the carrier frequency offset of the frequency domain OFDM signal in accordance with the estimated carrier frequency offset.

The utility model discloses a transmission way for uplink synchronization command words in OFDM mobile communication system, which is characterized in that uplink synchronization command words (SC) are sent to UE together with special dispatching information or packaged in protocol data units (PDU) and sent to UE to provide convenience for a receiver to conduct fast demodulation and timing adjustment. Transmission of uplink synchronization command words (SC) with special dispatching information to UE can meet the necessity of frequent adjustment of uplink synchronization in the network. In case of occasions that frequent adjustment of uplink synchronization is not needed, uplink synchronization codes (SC) are packaged in protocol data units (PDU) and sent to UE, which saves network resources and reduces signaling spending. The utility model also discloses a processing device and user device for synchronization command words (SC).

A demodulation device (1) in semiconductor technology is disclosed. The device (1) is capable of demodulating an injected modulated current. The device (1) comprises an input node (IN1), a sampling stage (DG1, IG1, GS1 IG2, DG2) and at least two output nodes (D1, D2). The sampling stage DG1, IG1, GS1, IG2, DG2) comprises transfer means (GL, GM, GR) for transferring a modulated charge-current signal from the input node (IN1) to one of the output nodes (D1, D2) allocated to the respective time interval within the modulation period. The small size and the ability to reproduce the device (1) in standard semiconductor technologies make possible a cost-efficient integration of the device (1).

The invention discloses a high resolution sensing system measuring beat-length and strain of a polarization maintaining optical fiber based on an optical frequency domain reflectometer (OFDR) system. The high resolution sensing system measuring the beat-length and the strain of the polarization maintaining optical fiber based on the OFDR system is characterized by comprising a linear frequency sweeping narrow line width light source, a polarizer, an interference system, a photoelectric detector, an optical heterodyne receiver and a signal processing system, wherein light produced by the linear frequency sweeping narrow line width light source is transformed to linearly polarized light through the polarizer and the linearly polarized light is injected to the interference system, the interference system is connected with the optical heterodyne receiver through the photoelectric detector, and the signal processing system is connected with the optical heterodyne receiver. The system is simple in structure, all-fiber-optical and controllable in linear frequency sweeping of a laser. By means of optical frequency domain detection, the problem that spatial resolution in time domain detection is limited by the optical pulse width and the data sampling rate is solved, high spatial resolution is obtained, and sensibility of the system can be improved and the dynamic range of the system can be enlarged through optical heterodyne detection.

The invention discloses a non-coherent spread spectrum communication device with variable data rate, which relates to realizing non-coherent spread spectrum modulation and demodulation data transmission with variable data rate bit by bit, configurable spread spectrum code rate, strong anti-Doppler performance and fast synchronization speed under the condition of low signal-to-noise ratio. Frequency sweep, parallel partial coherence and incoherent accumulation are used to realize the fast acquisition of incoherent spread spectrum signals with large frequency offset range, and digital average filter and square filter are used to achieve symbol timing synchronization of incoherent spread spectrum signals. The invention has high integration degree, strong portability, light weight and low power consumption, small commissioning workload of the whole machine, simple and flexible interface, easiness in expanding, and stable and reliable performance, the circuit is integrated in a 292mm long,185mm wide and 28mm high square terminal, weighing 0.6 kg, which is especially suitable for the application of non-coherent spread spectrum modulation and demodulation channel transmission terminal inairborne satellite communication system with limited volume and weight.

The invention discloses a China train control system (CTCS) point type transponder demodulating device. The device consists of a 4M antenna, a matching circuit, a power amplifier circuit, a band pass filter circuit, an analog / digital (AD) sampling module, a signal detection circuit, a field programmable gate array (FPGA), a rectification circuit and a through point detection circuit, wherein the FPGA consists of the AD sampling module, a differential module, a compatible integrated circuit (CIC) extraction filter module, a compensation filter, a finite impulse response (FIR) filter module and a signal judgment module. The CTCS point type transponder demodulating device can receive and demodulate effective data in a transponder in a wireless mode, can read and verify data written by programming equipment, and can demodulate data of transponders of other manufacturers. The technology can be applied to a transponder transmission module of vehicle-mounted receiving equipment. The CTCS point type transponder demodulating device can demodulate information quickly when a train drives at a high speed and passes through the transponder and provides safe and reliable operating data to a train operation control system. The device has the advantages of simple structure, low cost and high precision.

The invention discloses a fiber grating digital demodulation method and system based on the autocorrelation principle. The invention solves the problems of present fiber grating sensor system demodulation technology of low measuring precision, poor real-time performance, insufficient reuse ability, high price, unsatisfied engineering practical needs, etc. The invention has the advantages of high measuring precision, fast scanning speed, good real-time performance, strong reuse ability, high performance-price ratio, strong utility, etc. The structure of the invention includes a light source and at least a fiber grating sensor. Through a coupling device, the light source is connected with the fiber grating sensors which are successively linked in series. At the same time, the coupling device also can be connected with a tunable filter, which is linked with a photoelectric detector. The photoelectric detector is successively connected with a preamplifier and a digital-analog converter. The digital-analog converter is connected with the input terminal of a digital controller. The output terminal of the digital controller is connected with the controlling input terminal of the tunable filter via an electromechanical controller and an electromechanical modulation system in turn.

The invention discloses a photoelectric hybrid detection device based on a 2*4 90-degree optical bridge. The photoelectric hybrid detection device comprises a signal light source, a tunable local oscillator laser light source, a 2*4 90-degree free space optical bridge, a first balance detector, a second balance detector, a first mixer, a second mixer, a differentiator, a loop filter, a voltage-controlled oscillator, a signal receiver and a phase shifter. The photoelectric hybrid detection device is implemented via the mixture of light and the mixture of electricity, thus the requirement on the tunable local oscillator laser light source is reduced, and the phase change can be rapidly tracked and the rapid locking can be achieved. The photoelectric hybrid detection device plays an essential role in the implementation of the high-precision laser satellite communication in the future.

The invention relates to a signal processing apparatus and method. Disclosed herein is a signal processing apparatus, including: a computation device operable to perform transform computation adapted to Fourier-transform a time domain OFDM i.e., Orthogonal Frequency Division Multiplexing signal into a frequency domain OFDM signal; a processing device operable to perform carrier frequency offset detection adapted to detect an estimated carrier frequency offset that is an error of a carrier used for demodulation of the OFDM signal; and a carrier frequency offset correction device operable to perform carrier frequency offset correction adapted to correct the carrier frequency offset of the frequency domain OFDM signal in accordance with the estimated carrier frequency offset.

This invention relates to a demodulating apparatus and a demodulating method for demodulating an input signal more quickly than before when the channels of the input signal are inverted.A correlator 152 calculates a correlation value indicative of the correlation between a known delayed detection sequence made of symbols of correct delayed detection values of a known sequence inserted in the input signal and a received delayed detection sequence obtained through delay detection of the input signal. If the imaginary part of the correlation value is less than zero, a channel control section 132 switches the channels of the input signal before feeding the signal to a frame synchronization circuit 122. This invention can be applied illustratively to a satellite broadcast receiving apparatus.

The invention discloses a demodulation device and a demodulation method of a double-path quadrature phase optical fiber acoustic vibration sensor. According to the demodulation method, a light signalemitted by a light source (1) enters the optical fiber acoustic vibration sensor (3) through an optical fiber circulator (2), an external vibration signal causes vibration of a diaphragm of the optical fiber acoustic vibration sensor (3), and a modulated light signal is returned and divided into two signals through an optical fiber coupler (4); the two signals enter a birefringent crystal (6) through a double-path polarizer (5) to become two signals with a quadrature phase; the two signals are analyzed through a double-path analyzer (7); detection of the two optical signals is performed through a double-path photoelectric detector (8); a digital collection card (9) is adopted to perform signal collection; and cavity length change information is obtained finally after processing. Through the demodulation device and the demodulation method, effective demodulation of the optical fiber acoustic vibration sensor is realized, and the defects of previous relevant demodulation methods are overcome; and demodulation of high-frequency acoustic signals can be realized, the two signals with the stable quadrature phase are created, and the precision of a measurement result is guaranteed.

The invention provides a wide-temperature-range demodulation device and method based on low-frequency frequency agility and a sliding window. Laser emitted by a laser device is divided into two beamsof laser with the same power through an optical fiber coupler; one beam is modulated into pump light by a first electro-optical modulator driven by an electric pulse signal output by a frequency agility module, and the pump light is amplified by an erbium-doped fiber amplifier and enters a single-mode fiber to be measured; the other beam is modulated into probe light by a second electro-optical modulator driven by a microwave signal output by an up-conversion module, and the probe light is scrambled by a quadrature scrambler and then enters the to-be-measured single-mode optical fiber from theother end of the to-be-measured single-mode optical fiber; pump light and probe light interact in the single-mode optical fiber to be detected to generate a backward stimulated Brillouin scattering signal, a lower sideband light beam filtered by the fiber bragg grating filter is received by a photoelectric detector, and a generated electric signal is acquired by an acquisition card. The low-frequency agility technology is used for achieving rapid temperature demodulation, the response frequency exceeds 1Hz, and meanwhile, the equipment cost can be reduced, and the reliability can be guaranteed.

The invention provides a PDCCH detection method and device and user equipment. The method comprises the following steps: measuring downlink channel quality after accessing an NR cell; and according to the quality of the downlink channel, demodulating the candidate PDCCHs corresponding to the aggregation levels according to the sequence of the aggregation levels from small to large or from large to small in the search space until the PDCCHs sent by the network side are detected. According to the invention, the order of the aggregation levels of the PDCCH can be automatically adjusted and demodulated according to the downlink channel quality, so that the number of blind detection times is reduced, the blind detection complexity is reduced, and the blind detection efficiency is improved.

The invention relates to the technical field of communication, and particularly discloses a short-wave antenna optimization system which comprises a parameter configuration and display module, a datastorage module, an address recognition module, an antenna selection module, an antenna state detection module, an automatic antenna switching module, a power supply module and the like. The short-wavecommunication system allocates serial numbers to each pair of antennas according to acquired short-wave antenna characteristic parameters, when the short-wave communication system communicates with other stations, the short-wave communication system sends a message containing coding information of the other stations, address demodulation is carried out by designing a special demodulator, and address codes of the other station are identified by an address identification module. After the address code of the opposite radio station is obtained, the system automatically controls a transmitting antenna exchange controller to preferably select a transmitting antenna and automatically controls a receiving antenna exchange controller to preferably select a receiving antenna, so that the radiationpower of the transmitting antenna and the receiving signal gain of the receiving antenna are improved, and the optimal communication effect is achieved.

The invention discloses a signal tracking demodulation system and method based on a dual-channel receiver. The system comprises a large-frequency-offset carrier tracking unit and a demodulation unit.According to the method, the large-frequency-offset carrier tracking unit is used for quickly capturing and tracking a large-frequency-offset signal of a sum path; and accurate demodulation of the differential signals is achieved through the demodulation unit. Through the dual-channel setting of the receiver, the 0 / pai modulation of the sum path signal and the differential path signal is avoided,the separation processing of the sum path signal and the differential path signal is realized, and the whole tracking locking process is simplified; and meanwhile, quick tracking of satellite antennareceiving signals and accurate demodulation of an error angle are realized.

The invention discloses a laser wavelength real-time monitoring method based on a polarization optical fiber interferometer, which comprises the following steps of: acquiring four paths of interference signals with phase shifts of 0 degree, 90 degrees, 180 degrees and 270 degrees by using a polarization optical fiber interferometer system wavelength real-time monitoring device; the four paths of space phase-shifting interference signals carrying real-time wavelength information are demodulated through a four-step phase-shifting method to obtain corresponding phase information, then wavelength information is obtained, and real-time monitoring of the wavelength of the laser is achieved. A polarization maintaining optical fiber and a device are adopted in the polarization optical fiber interferometer system, synchronous phase shifting is achieved, and meanwhile the problem of amplitude jitter caused by the unstable polarization direction of interference light in a common optical fiber interferometer is solved. According to the invention, only one four-quadrant detector is needed to obtain the light intensity information of four pixels, and the wavelength variation can be fed back, so that the error problem caused by long displacement is avoided, the cost is reduced, the method has the characteristics of low insertion loss, high sampling rate and high precision, and the real-time wavelength monitoring of the laser can be realized.

A complement code demodulation system is used in two order coherence operation modulation system and a block domodem device in RAN which has a two order conherent character, utilizing incomplete orthogonal character between complement codes to decide the successive second order coherent operation according to the first by complement codes participating in the first and second coherent operation to reduce the operation to get the transferred complement codes quickly so as to simplify the hardware structure to increase the demodem speed including multiple address form first and second operationcircuits and multiple process modules form the third one having the function of third operation and fourth maximum value of known basic demodem device.

The invention discloses an active three-dimensional reconstruction system and method based on linear structured light rotation scanning. The system comprises an image acquisition module, a rotary table motion module, a rotary table motion control module, an image processing module, a three-dimensional coordinate calculation module, a data transmission and reading module and a display module. The image acquisition module is arranged on the rotary table motion module, the rotary table motion module is connected with the rotary table motion control module, and the rotary table motion control module controls the rotary table motion module to rotate. The method can reconstruct and measure the three-dimensional shape information of the to-be-measured target, and has the characteristics of reasonable structure, high adaptability, high reconstruction precision and the like. Compared with a traditional three-dimensional reconstruction system based on a translation slide rail, the system adopts a rotary acquisition mode, so that the equipment size is smaller, the occupied space during operation is smaller, and a mechanical jitter error introduced in a traditional linear translation process can be effectively avoided.

The invention discloses a frequency multiplexing and demultiplexing multichannel grating demodulation device and method. The sensing device comprises a linear sweep frequency laser, a first optical fiber coupler, a second optical fiber coupler, an optical fiber circulator, an optical fiber beam splitter, a plurality of acousto-optic frequency shifters, an FBG (Fiber Bragg Grating), a photoelectric detector, a data acquisition card and a computer. Based on a coherent detection technology, multi-channel signals are subjected to frequency multiplexing, photoelectric signal conversion is realized in a single photoelectric detector, a single-channel acquisition card is used for analog-to-digital conversion, an FPGA in the acquisition card is used for realizing FFT operation, and a physical position and a spectral signal of a to-be-detected FBG are output. And finally, performing a series of data processing operations such as window inverse Fourier transform and the like in calculation to obtain temperature and strain fast demodulation. According to the invention, multi-channel fast fiber grating demodulation can be realized, sweep-frequency light source multiplexing and single-channel acquisition are realized, and the cost of the demodulation device is greatly saved on the premise of meeting the performance.

The invention provides a long-distance and wide-measurement-range rapid demodulation device and method. The device comprises a laser, a first optical fiber coupler, a first electro-optical modulator IM1, a second optical fiber coupler, a delay optical fiber, a third optical fiber coupler, an erbium-doped optical fiber amplifier EDFA, a pulse module, a second electro-optical modulator IM2, an optical isolator, a microwave source module, a first circulator R1, a second circulator R2, a fiber grating filter, a photoelectric detector, an acquisition card and a to-be-tested single-mode fiber. According to the scheme, rapid temperature measurement is achieved through a polarization separation detection technology, and temperature demodulation is achieved through artificial neural network. Meanwhile, the difference pulse is used for improving the spatial resolution by adopting the Brillouin optical time domain analysis technology, and two optical pulses with different pulse widths are also required to be differentiated, and the polarization separation detection technology is used for generating the two optical pulses with different widths at one time to replace the switching of the two pulses, so that the pulse switching time is saved during measurement, and the measurement speed is further improved.

The invention belongs to the technical field of nondestructive testing and relates to a multi-beam automatic scanning imaging method based on a flexible ultrasonic array transducer. The method comprises the main process steps comprising multi-beam automatic interpolation scanning, multi-beam scanning imaging information extraction and reconfiguration, multi-beam scanning imaging display and the like. The method has the following beneficial effects: according to the combination of ultrasonic testing channels and the beam coverage rule, multimode multi-beam ultrasonic automatic interpolation scanning with different resolution ratios is realized, thus the ultrasonic scanning efficiency is manyfold improved and the surface testing dead zone and longitudinal resolution can reach about 0.15mm; the time domains and two-dimensional amplitude information which are generated by propagation of the ultrasonic waves in such structures as composites and the like are utilized to carry out scanning imaging; various information in the parts is reproduced through imaging; and the single valued mapping relationships between the imaging domains and the tested parts are established, thus realizing imaging display of the multi-beam automatic interpolation scanning testing result that such structures as large composites do not lose testing point information.

The invention discloses a dual-laser interference nanoscale positioning measurement system which comprises a light source, a first beam splitter prism, a first rectangular prism, a second rectangular prism, a second beam splitter prism, a scalar interference light acquisition module, a vector interference light acquisition module and a displacement calculation module. A photoelectric detector collects the light intensity of reflected interference light in the position moving process of an object to be detected and generates a periodic light intensity change curve, and a CCD camera collects vortex interference photoelectric images before and after the position of the object to be detected moves. The displacement of the to-be-detected problem is calculated according to the integer period of the light intensity change curve and the change angle of the image of the vortex interference light before and after the position of the to-be-detected object is moved, the reflection interference light collected by the photoelectric detector is a scalar signal, the vortex interference light collected by the CCD camera is a vector signal, and the displacement is calculated comprehensively by combining the two signals. And the measurement resolution is improved, and meanwhile, the interference signals are quickly acquired and demodulated.