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40results about How to "Suppress phase noise" patented technology
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Method and device for suppressing phase noise of long-distance optical fiber interference system based on optical path difference matching
ActiveCN103837166AReduce phase noiseImprove the maximum input power and transmission distanceSpecial purpose recording/indication apparatusPhysicsOptical path
The invention relates to an optical fiber sensing technology and provides a method and device for suppressing phase noise of a long-distance optical fiber interference system based on optical path difference matching so as to solve the problems that the input power of the existing long-distance optical fiber interference system is limited and the phase noise of the existing long-distance optical fiber interference system is increased under the stimulated Brillouin scattering effect. The device comprises a single-frequency laser, an electro-optic phase modulator, a signal source, an erbium-doped optical fiber amplifier, a transmission optical fiber, a matching interferometer, a photoelectric detector and a signal acquisition and processing device. A laser is output by the single-frequency laser and modulated by the electro-optic phase modulator to generate a multi-frequency laser, the multi-frequency laser is amplified by the erbium-doped optical fiber amplifier and input into the matching interferometer by the transmission optical fiber, and a signal is output of the matching interferometer, detected by the photoelectric detector and processed by the signal acquisition and processing device. Suppression on the stimulated Brillouin scattering effect is achieved through the phase modulation technology, the phase noise of the system is reduced through signal frequency phase modulation and interferometer optical path difference matching, and the maximum input power and sensing distance of the system are increased.
Owner:NAT UNIV OF DEFENSE TECH
Double-conjugation pumping modulating signal all-optical regeneration device and method based on optical frequency comb
ActiveCN103885266ASuppress phase noiseReduce signal error rateNon-linear opticsBandpass filteringPhase noise
The invention discloses a double-conjugation pumping modulating signal all-optical regeneration device based on an optical frequency comb. The all-optical regeneration device comprises a pumping laser device, the optical frequency comb, a photodecomposition multiplexer, a first coupler, erbium-doped optical fibers, a second coupler, a first section of HNLF, a wavelength selective switch, a second section of HNLF and a light bandpass filter. The device can be used for phase position regeneration of various degraded QPSL signals (including DQPSK) in a high-speed optical fiber communication network, so that influence on performance of an optical communication system by phase noise is reduced, the all-optical relay transmission distance is improved, and the error rate of a receiver is reduced. The invention further discloses a double-conjugation pumping modulating signal all-optical regeneration method based on the optical frequency comb. The double-conjugation pumping modulating signal all-optical regeneration device has the advantages of being concise in structure, stable in performance, easy to operate, remarkable in regeneration effect and the like.
Owner:JIANGSU JINDI ELECTRONICS TECH
Phase-shifting fiber Bragg grating strain sensing system based on photoelectric oscillator
A phase-shifting fiber Bragg grating strain sensing system based on a photoelectric oscillator comprises a wave-length tunable laser; an input end of a polarization controller is connected with an output end of the wave-length tunable laser; a light input end of a phase modulator is connected with an output end of the polarization controller; an end a of an optical circulator is connected with an output end of the phase modulator; one end of a phase fiber Bragg grating pi is connected with an end b of the optical circulator; an input end of a photoelectric detector is connected with an end c of the optical circulator; an input end of a microwave power beam splitter is connected with an output end of the photoelectric detector; an input end of a microwave power amplifier is connected with a first output end of the microwave power beam splitter; an output end of the microwave power amplifier is connected with a radio frequency input end of the phase modulator; an input end of a frequency spectrograph is connected with a second output end of the microwave power beam splitter.
Owner:INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI
Modulator circuit of digital transmitter, digital transmitter and signal modulation method
ActiveCN104052710AAvoid high frequency harmonic componentsSuppress phase noisePulse automatic controlMultiple carrier systemsLocal oscillator signalRadio frequency signal
The invention relates to a modulator circuit of a digital transmitter, the digital transmitter and a signal modulation method. The modulator circuit comprises a first synchronous circuit and a digital modulator, wherein the first synchronous circuit comprises a first synchronous unit and a second synchronous unit, the first synchronous unit and the second synchronous unit are used for obtaining corresponding delayed signals after carrying out phase delay on a first local oscillator signal and a second local oscillator signal respectively, and carrying out phase adjustment on digital baseband signals through the delayed signals to generate a first adjusting signal and a second adjusting signal respectively, and the rising edge and the falling edge of the first adjusting signal can fall in a low-level interval of the first local oscillator signal; the rising edge and the falling edge of the second adjusting signal fall in the low-level interval of the second local oscillator signal; the digital modulator modulates the first adjusting signal through the first local oscillator signal to generate a first radio frequency signal, and modulates the second adjusting signal through the second local oscillator signal to generate a second radio frequency signal.
Owner:HUAWEI TECH CO LTD
Method and device for phase noise suppression of remote optical fiber interference system in spectral line operation
ActiveCN103727966ASuppress phase noiseReduce phase noiseConverting sensor output opticallyPhase noisePhase difference
The invention relates to an optical fiber sensing technology and provides a method and device for phase noise suppression of a remote optical fiber interference system in spectral line operation. The device comprises a narrow linewidth single frequency laser, a first electro-optic phase modulator, an erbium-doped optical fiber amplifier, a transmission optical fiber, a second electro-optic phase modulator, an optical fiber Michelson interferometer, a photoelectric detector and a signal collecting and processing device. The method comprises the steps of applying modulating signals at the input end of the transmission optical fiber through the electro-optic phase modulators to generate multifrequency laser, utilizing the modulating signals of the electro-optic phase modulators again at the output end of the transmission optical fiber to recover the multifrequency laser generated by modulation to single frequency laser, simultaneously enabling phase difference between the two modulating signals to be odd number times of pi, and enabling the two modulating signals to have identical frequency and amplitude. The two electro-optic phase modulators are utilized to achieve recoverable spectral line operation, an SBS is suppressed, system phase noises are reduced, and accordingly maximum input power and the sensing distance of a sensing system are improved.
Owner:NAT UNIV OF DEFENSE TECH
Correction method for phase noise of multi-antenna OFDM system receiving terminal
InactiveCN101478524ASuppress phase noiseImprove performanceMulti-frequency code systemsMultiple carrier systemsPhase noiseSignal on
The invention relates to a correction method of phase noise at a multi-antennae Orthogonal Frequency Division Multiplexing (OFDM) system receiving end belonging to the wireless data-transmission field. The method places a pilot OFDM symbol every a plurality of data OFDM symbols. In the pilot symbols, the receiving end obtains a channel matrix of the current symbol as a reference channel matrix of subsequent data symbols according to a receiving signal on a pilot sub-carrier and the receiving end pilot. In the data symbols, the receiving end obtains the channel matrix of the current symbol according to the receiving signal on the pilot sub-carrier and a reservation signal at the receiving end and obtains a united matrix of a transceiving phase noise mean values by comparing the channel matrix with that of the pilot symbol. According to an estimate value of the transceiving phase noise mean values which are separated from the united matrix, a detection matrix is adjusted. The method can simultaneous estimate and correct the phase noise of the transmitting and receiving antennas, and improve the system performance.
Owner:TSINGHUA UNIV
Phase unwrapping algorithm based on modified embedded cubature Kalman filtering (MECKF)
ActiveCN106932773AReduce difficultyFix unwrapping issuesRadio wave reradiation/reflectionKaiman filterEstimation methods
The invention discloses a phase unwrapping algorithm based on MECKF. According to the algorithm, an embedded cubature Kalman filter modified via a Levenberg-Marquardt method, a local phase gradient estimation algorithm based on a corrected matrix beam model (AMPM) and a quantified tracking strategy are combined to unwrap a wound phase image accurately in high efficiency. The algorithm comprises the main steps that a recursion state estimation model of the phase unwrapping algorithm based on MECKF is established, and the phase gradient estimation method based on the AMPM is used to obtain phase gradient information needed by the recursion state estimation model; and the quantified path guiding graph strategy, the recursion state estimation model of the phase unwrapping algorithm based on MECKF is guided to unwrap wound pixels rapidly along a path from a high-quality area to a low-quality area till phases of all wound pixels are unwrapped. The algorithm is characterized by higher precision and robustness.
Owner:GUILIN UNIV OF ELECTRONIC TECH
Phase noise inhibition method based on continuous carrier aggregation
InactiveCN109194594ASolve problems that cannot be separated from CIRSuppress phase noiseChannel estimationTransmitter/receiver shaping networksChannel state informationTime domain
The present invention belongs to the technical field of wireless communication, and relates to phase noise inhibition method based on continuous carrier aggregation. The present invention designs a method for inhibiting phase noise through adoption of channel sparse features. The method comprises the steps of: performing frequency domain conversion of receiving signals, extracting pilot frequencyreceiving signals from the receiving signals, initially estimating channel impulse response, employing the sparse features of the channel impulse response (CIR) to design a time-domain filter to further estimate the channel impulse response, and obtaining the channel frequency domain response through FFT operation to estimate transmission data. The channel impulse response obtained through combination of the channel estimation and the CPE solves the problems that the CPE cannot be separated from the CIR, and performs simultaneous inhibition of the two distortions of the CPE and the ICI causedby phase noise in a condition without channel prior information so as to make up the deficiency of a traditional method at the aspect of inhibition of the CPE and the ICI.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA +1
High-precision pilot frequency digital phase-locked loop system based on fuzzy region pulse detection
ActiveCN113395069AHigh synchronization accuracyHigh-resolutionPulse automatic controlPhase detectorPhase noise
The invention provides a high-precision pilot frequency digital phase-locked loop system based on fuzzy region pulse detection. The high-precision pilot frequency digital phase-locked loop system comprises a frequency scale module, a DDS module, a signal pulse conversion module, a pilot frequency group phase coincidence point pulse module, a phase difference measuring and processing module, a voltage-controlled crystal oscillator module, a display module and a power supply module. Compared with an existing high-precision phase-locked loop, a phase discriminator is not needed, a fuzzy region pulse detection method is adopted, the resolution of phase difference measurement is greatly improved, the resolution of phase difference measurement at any moment is better than 1 ps, the synchronization precision of the phase-locked loop is greatly improved, the system structure is integrated through the FPGA technology, the development cost is reduced, the phase noise is suppressed, and the stability and reliability of the system are enhanced.
Owner:郑州轻大产业技术研究院有限公司
Microwave photon radio frequency phase shifter based on spectral processing and phase shifting method thereof
The invention discloses a microwave photon radio frequency phase shifter based on spectrum processing and a phase shifting method thereof. The phase shifter comprises a laser source, an optical modulator, an optical fiber amplifier, a spectrum processing system, a photoelectric detector and an optical coupler. The optical amplification signal of the optical fiber amplifier is incident on the diffraction grating and is separated into a plurality of reflected light rays. Different spectral components in the plurality of reflected light rays are projected on different pixel points of each row, and the same spectral components are projected on different pixel points of each column. The laser processor modulates the amplitude and phase of the spectral component and forms a plurality of beat frequency light waves. Each optical coupler synthesizes an optical carrier wave and a first-order modulation sideband in a spectrum manner to generate an optical single sideband modulation signal. The optical single sideband modulation signal is subjected to beat frequency in a photoelectric detector to generate a radio frequency signal. The phase noise of the photon radio frequency phase shifter iseffectively restrained, the photon radio frequency phase shifting function is achieved, scanning at any angle can be achieved, flexibility is high, reconfiguration is achieved, and the phase shifter is suitable for large-scale phased array radar.
Owner:INNER MONGOLIA UNIVERSITY
Dual-loop compensation orthogonal signal source phase noise restraining circuit based on lock-in amplifier
ActiveCN104201992ASuppress phase noiseLow phase noiseAmplifier modifications to reduce noise influencePhase detectorPhase sensitive
The invention discloses a dual-loop compensation orthogonal signal source phase noise restraining circuit based on a lock-in amplifier. An output orthogonal component of a quarter frequency divider is connected with the input side of a phase sensitive detector, and the output side of the phase sensitive detector is connected with the input negative terminal of an integrator. The output side of a half Vos measuring circuit is connected with the input positive terminal of the integrator. The output side of the integrator is connected with the input side of a #1 low pass filter. The output side of the low pass filter is connected the negative terminal of a comparator, and the output side of the comparator is connected with the input side of a phase frequency detector. The cophase component output side of the quarter frequency divider is connected with the input side of the phase frequency detector, the output side of the phase frequency detector is connected with the input side of a #2 low pass filter, the output side of the #2 low pass filter is connected with the input side of a voltage-controlled oscillator, and the output side of the voltage-controlled oscillator is connected with the input side of the quarter frequency divider. A signal source is connected with the input side of the phase sensitive detector, the input side of the half Vos measuring circuit and the input side of the comparator. The dual-loop compensation orthogonal signal source phase noise restraining circuit compensates for the phase offset caused by phase noise, and can effectively restrain the phase noise and ensure the eddy measuring accuracy.
Owner:JIANGSU SMART TECH
Coherent optical wireless optical communication transmission method and system, storage medium and equipment
InactiveCN111865428AImprove performanceImprove transmission distanceTransmission noise reductionElectromagnetic receiversStreamOptical wireless
The invention belongs to the technical field of free space optical communication, and discloses a coherent optical wireless optical communication transmission method and system, a storage medium and equipment, and the method comprises the steps: carrying out the symbol mapping of data through three variables: a phase, a polarization state and a data symbol bit, so as to generate baseband symbol streams in X and Y polarization states; and enabling the four paths of baseband signals to be sequentially subjected to I / Q imbalance compensation, channel equalization, time sequence recovery, carrierfrequency offset compensation and carrier phase offset compensation to obtain two paths of symbol data streams corresponding to the generated baseband signals. Phase noise caused by atmospheric turbulence can be effectively suppressed, and crosstalk between polarization states in the same symbol time slot period can be effectively avoided by cross-modulating symbol information in two adjacent symbol periods in the orthogonal polarization state. Therefore, the performance of the traditional atmospheric coherent light communication system based on the PSK or QAM modulation mode can be effectively improved, and the transmission distance of the atmospheric laser communication system is expanded.
Owner:XIJING UNIV
All-optical phase noise inhibition method for coherent detection
Owner:HUAZHONG UNIV OF SCI & TECH
Phase-locked loop system and implementation method for same
InactiveCN102882518ASuppress phase noiseSuppress noisePulse automatic controlPhase noiseLow-pass filter
The invention discloses a phase-locked loop system, which comprises an input end, an output end, a first phase frequency detector, a first charge pump connected with the first phase frequency detector, a first low-pass filter connected with the first charge pump, a first voltage-controlled oscillator connected with the first charge pump and the first low-pass filter, a second phase frequency detector connected with the first voltage-controlled oscillator, a second charge pump connected with the second phase frequency detector, a second low-pass filter connected with the second charge pump, a second voltage-controlled oscillator connected with the second charge pump and the second low-pass filter, a first digital frequency divider connected between the first phase frequency detector and the second voltage-controlled oscillator, and a second digital frequency divider connected between the second phase frequency detector and the second voltage-controlled oscillator. The invention also discloses a working method of the phase-locked loop system. Input noise and the phase noise of the second voltage-controlled oscillator can be simultaneously suppressed, so that the noise of the phase-locked loop system is greatly reduced.
Owner:IPGOAL MICROELECTRONICS (SICHUAN) CO LTD
Optical frequency transmission device and method based on time delay
ActiveCN114006660ASuppress phase noiseImprove stabilityElectromagnetic receiversPhase noiseOptical frequencies
The invention discloses an optical frequency transmission device and method based on time delay. The device is composed of a local end, a transmission link and a relay end, wherein the input light signal of the local end is transmitted to the relay end through the transmission link, and the output light signal of the slave laser device of the relay end is transmitted to the local end through the same transmission link and then is reflected back to the relay end again. In the method, two paths of signal light passing through a transmission link arrive at a relay end and then are input into an optical frequency delay comparison unit to obtain a relative frequency deviation between a master laser device and a slave laser device, and the signal frequency of output light of the slave laser device is fed back and controlled by using the relative frequency deviation, so that the frequency between the light signals input from the laser device and the local end is relatively stable. According to the invention, different additional time delays are applied to the two paths of light signals to carry out frequency comparison with a traditional transmission method, so that phase noise introduced by a transmission link can be reduced; and the relay station can perform optical frequency transmission to the next link by adopting a phase compensation mode, so that cascaded optical frequency transmission is realized.
Owner:SHANGHAI JIAO TONG UNIV
Clock circuit and clock signal generation method
The invention discloses a clock circuit. The clock circuit comprises a first inductance-capacitance type phase-locked loop and a first annular phase-locked loop, the first inductance-capacitance typephase-locked loop is used for carrying out frequency multiplication processing on a first input clock signal to generate a first high-frequency clock signal, and the first annular phase-locked loop isused for carrying out frequency multiplication processing on the first high-frequency clock signal to generate a first target clock signal. According to the present invention, the technical problem that a clock signal with high speed, wide frequency and low jitter cannot be provided in the prior art, is solved.
Owner:XI AN UNIIC SEMICON CO LTD
Temperature compensation accelerometer based on polarization maintaining optical fiber double-arm heteroaxial interferometer
PendingCN112485467AReduce the effect of temperatureIncrease heightAcceleration measurement using interia forcesAccelerometerPolarization-maintaining optical fiber
The invention provides a temperature compensation accelerometer based on a polarization maintaining optical fiber double-arm heteroaxial interferometer. An all-polarization-maintaining optical fiber interferometer is adopted as a sensing light path, a sensing arm of the interferometer is welded in a staggered-axis mode to achieve double-arm different-axis interference, and optical fibers of the two sensing arms of the interferometer are sensitive to strain and temperature at the same time; a polarization maintaining optical fiber interferometer and a push-pull type mechanical vibration pickupstructure are compounded, acceleration is converted into optical fiber strain through a vibration pickup structure, and two sets of sensing systems which have different responses to temperature and acceleration at the same time are constructed in the same sensor. In the sensor, the temperature response and the acceleration response of the two sensing systems are the temperature effect difference value and the strain effect sum of the two sensing arms respectively, and under the balance interferometer, the temperature response coefficients of the two sensing systems are equal in numerical valueand opposite in symbol, and the acceleration response symbols are the same. Phase responses of the two sets of sensing systems are added, the strain response is increased while the temperature response is eliminated, and the acceleration sensitivity of the sensor is improved.
Owner:GUANGDONG UNIV OF TECH
Phase-shifting fiber Bragg grating strain sensing system based on photoelectric oscillator
A phase-shifting fiber Bragg grating strain sensing system based on a photoelectric oscillator comprises a wave-length tunable laser; an input end of a polarization controller is connected with an output end of the wave-length tunable laser; a light input end of a phase modulator is connected with an output end of the polarization controller; an end a of an optical circulator is connected with an output end of the phase modulator; one end of a phase fiber Bragg grating pi is connected with an end b of the optical circulator; an input end of a photoelectric detector is connected with an end c of the optical circulator; an input end of a microwave power beam splitter is connected with an output end of the photoelectric detector; an input end of a microwave power amplifier is connected with a first output end of the microwave power beam splitter; an output end of the microwave power amplifier is connected with a radio frequency input end of the phase modulator; an input end of a frequency spectrograph is connected with a second output end of the microwave power beam splitter.
Owner:INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI
Phase Unwrapping Algorithm Based on Modified Embedded Volumetric Kalman Filter
ActiveCN106932773BReduce difficultyFix unwrapping issuesRadio wave reradiation/reflectionKaiman filterEstimation methods
The invention discloses a phase unwrapping algorithm based on MECKF. According to the algorithm, an embedded cubature Kalman filter modified via a Levenberg-Marquardt method, a local phase gradient estimation algorithm based on a corrected matrix beam model (AMPM) and a quantified tracking strategy are combined to unwrap a wound phase image accurately in high efficiency. The algorithm comprises the main steps that a recursion state estimation model of the phase unwrapping algorithm based on MECKF is established, and the phase gradient estimation method based on the AMPM is used to obtain phase gradient information needed by the recursion state estimation model; and the quantified path guiding graph strategy, the recursion state estimation model of the phase unwrapping algorithm based on MECKF is guided to unwrap wound pixels rapidly along a path from a high-quality area to a low-quality area till phases of all wound pixels are unwrapped. The algorithm is characterized by higher precision and robustness.
Owner:GUILIN UNIV OF ELECTRONIC TECH
A Fractional Frequency Division Circuit for Spurious Suppression
ActiveCN105049039BFlexible designFlexible design cyclePulse automatic controlPhase detectorLoop filter
The invention belongs to the field of signal sources, and specifically discloses a fractional frequency division circuit for stray suppression. The fractional frequency division circuit includes a phase detector, a loop filter, and a voltage-controlled oscillator connected in sequence; in addition, the fractional frequency division circuit also includes a frequency divider, a synchronization module, and a Σ-Δ modulator; wherein, the voltage-controlled oscillation The output signal of the detector, one way is directly output, and the other way is fed back to the frequency divider; the reference clock signal is divided into two ways, one way is divided by two and enters the phase detector as the phase detector reference clock signal, and the other way is used as the clock signal of the synchronization module , used to beat the frequency division ratio generated by the Σ-Δ modulator into the frequency divider; one way of the frequency-divided clock signal generated by the frequency divider enters the phase detector, and the other enters the Σ-Δ modulator and is used as a Σ-Δ modulation device clock signal. Compared with the fractional frequency division circuit in the prior art, the present invention adds a frequency divider and a synchronization module, and at the same time adds a random jitter module inside the FPGA to suppress the limit cycle phenomenon, further reducing spurs.
Owner:CHINA ELECTRONIS TECH INSTR CO LTD
OCT (optical coherence tomography)-based high-sensitivity measurement system and method with large dynamic range of flow speed
ActiveCN102657519BRealize measurementSuppress phase noiseSensorsBlood flow measurementCMOSComputational physics
The invention discloses an OCT (optical coherence tomography)-based high-sensitivity measurement system and method with a large dynamic range of flow speed. According to the measurement system and method disclosed by the invention, a two-dimensional scanning strategy combining fast scanning driven by saw-tooth waves and slow-speed scanning driven by step waves is adopted, and a high-speed CMOS (complementary metal oxide semiconductor) camera is utilized for acquiring an interference spectrum. A traditional phase resolution algorithm is adopted in the fast scanning direction for extracting high-flow-speed information, and a high-order correlation phase resolution algorithm is adopted in the slow-speed scanning direction for extracting slow-flow-speed information and a phase variance value corresponding to the large dynamic rate of the flow speed. A flow speed image is synthesized from the high-flow-speed information and the slow-flow-speed information. After space filtering and binarization are performed on a phase variance image, a mask image is obtained, and the flow speed image is processed by the mask image to get the final flow speed image. According to the measurement system and method disclosed by the invention, the dynamic range of measurement flow speed can be expanded, and the noise-limited speed detection sensitivity is further broken through.
Owner:ZHEJIANG UNIV
A Fiber Laser Frequency Stabilization System Using Fast and Slow Locking
ActiveCN112134136BAchieving a Modulated ResponseSimple structureActive medium shape and constructionFrequency stabilizationLine width
The invention provides a fiber laser frequency stabilization system using fast and slow locking, which includes an ultra-narrow linewidth fiber laser, an acousto-optic modulator, a phase modulator, a quadrature demodulation device and a feedback control device. It is characterized in that the laser output from the ultra-narrow linewidth fiber laser is modulated by an acousto-optic modulator and a phase modulator in sequence. After being input into a fiber grating Fabry-Perot interference cavity through a circulator, it is demodulated through a quadrature demodulation circuit. The slow PID controller is used to adjust the wavelength of the light source to compensate low frequency signals; the fast PID controller is used to adjust the acousto-optic modulator to compensate high frequency signals. This scheme can overcome the limitations of the frequency modulation response and frequency modulation bandwidth of the fiber laser, and realize the stable tracking between the output wavelength of the fiber laser and the reference resonant cavity.
Owner:HARBIN ENG UNIV
Wireless coherent CDMA (Code Division Multiple Access) optical communication system and communication method
InactiveCN106850077ASuppress phase fluctuationSuppress phase noiseElectromagnetic receiversCommunications systemLight beam
The invention discloses a wireless coherent CDMA (Code Division Multiple Access) optical communication system and communication method. The system comprises a laser, a signal source, a transmitter module and a receiver module. Light generated by the laser is split into two light waves, and the two light waves are modulated and then are combined into one way of light through a coupler for transmission. A receiving antenna couples space light into an optical fiber. The light is split into two light beams. The two light beams are modulated through modulation signals corresponding to orthogonal codes of a transmitter end. The light beams are processed through the coupler and are converted into a light current through a balance detector. The light current is output and processed, so an information sequence sent by the transmitter end is obtained. According to the method and the system, a coherent CDMA mode is employed; phase fluctuation resulting from atmosphere channels is suppressed; the method and the system are applicable to a wireless optical communication multi-user access system; a channel utilization rate of the system is improved; the interference among the users is reduced; the relatively high performance and relatively low system complexity are achieved; and the practicability of the system is facilitated.
Owner:PEKING UNIV
A microwave or radio frequency power-free broadband carrier cancellation signal detection method
ActiveCN109921821ASuppress phase noiseLarge carrier compression ratioPhase-modulated carrier systemsMicrowaveCarrier signal
Based on a microwave or radio frequency power-free broadband carrier cancellation signal detection method, a weak vibration sensor technology taking microwave or radio frequency as a carrier is combined with an interferometer technology, and a demodulation technology based on the carrier cancellation technology is used for realizing high-sensitivity detection of weak vibration; A microwave or radio frequency signal passes through a power divider to obtain two paths of output, the two output ends are connected with two arms of an interferometer respectively, and the two arms of the interferometer, namely a sensor arm and an amplitude-phase adjusting arm, are connected to a vibration sensor and an amplitude-phase adjuster respectively through circulators; A vibration sensing element of the sensor arm is biased by microwaves or radio frequency, and the vibration sensing element is subjected to phase modulation. The amplitude-phase adjusting arm ensures the realization of carrier cancellation; Sending to a receiving end through a circulator; A demodulation technology is applied, and micro-vibration information is restored after demodulation; According to the demodulation technology, ahomodyne mixing and orthogonal demodulation technology is adopted, so that a matte point is eliminated, and the noise is reduced.
Owner:CHANGZHOU HIGH TECH RES INST OF NANJING UNIV
All-optical phase regeneration device and method based on double-conjugate pump phase modulation signal
ActiveCN103885266BSuppress phase noiseReduce signal error rateNon-linear opticsBandpass filteringPhase noise
Owner:JIANGSU JINDI ELECTRONICS TECH
Modulation circuit of digital transmitter, digital transmitter and signal modulation method
ActiveCN104052710BAvoid high frequency harmonic componentsSuppress phase noisePulse automatic controlMultiple carrier systemsLocal oscillator signalEngineering
The invention relates to a modulation circuit of a digital transmitter, a digital transmitter and a signal modulation method. The modulation circuit includes: a first synchronous circuit and a digital modulator; wherein, the first synchronous circuit includes a first synchronous unit and a second synchronous unit, which respectively phase-delay the first local oscillator signal or the second local oscillator signal Obtain the corresponding delay signal, and use the delay signal to adjust the phase of the digital baseband signal to generate the first adjustment signal and the second adjustment signal, so that the rising edge and falling edge of the first adjustment signal respectively fall on the first phase In the low-level interval of the oscillator signal; and the rising edge and falling edge of the second adjustment signal respectively fall in the low-level interval of the second local oscillator signal; the digital modulator uses the first local oscillator signal to perform the first adjustment signal modulating, generating a first radio frequency signal, and modulating the second adjustment signal with the second local oscillator signal to generate a second radio frequency signal.
Owner:HUAWEI TECH CO LTD
Remote high-frequency microwave oscillation source system based on single-stage nonlinear spectrum expansion
PendingCN112217566ASuppress phase noiseSuppress noiseDistortion/dispersion eliminationFiber-optic communicationInformation technology
The invention provides a remote high-frequency microwave oscillation source system based on single-stage nonlinear spectrum expansion. A same DFB laser light source is adopted to generate high-speed light millimeter waves and a remote high-frequency microwave oscillation source, so that phase noise can be effectively suppressed; the adopted DFB laser has the characteristics of narrow linewidth andhigh side mode rejection ratio, and can effectively suppress intensity noise; the remote high-frequency microwave oscillation source provided by the invention is novel in generation scheme, simple and feasible, and can effectively suppress noise. The method and the system can be used as an important reference for exploring and researching a high-bit-rate optical millimeter wave system, and can provide important support for deep research in the fields of microwave photonics, nonlinear optics, optical fiber communication, optical information processing, a new generation of information technology and the like.
Owner:LIAOCHENG UNIV
Detection system and method of resonant optical gyroscope based on quadrature demodulation
ActiveCN108168537BSuppress phase noiseImprove signal-to-noise ratioSagnac effect gyrometersResonant cavityPhase noise
The invention discloses a quadrature demodulation-based detection system and a quadrature demodulation-based detection method of a resonator optic gyro. Firstly, the phase of laser input to an opticalring resonant cavity is modulated, and synchronous quadrature demodulation is performed on clockwise and counterclockwise output signals going out of the cavity, wherein one quadrature demodulation signal is processed and then serves as an error signal for controlling the frequency of a laser through a servo loop, so that the output light frequency of the laser is locked at the resonant frequencythereof in a tracking manner; the other quadrature demodulation signal is processed and then output as a gyro signal. By the detection method of the resonator optic gyro, provided by the invention, automatic adjustment of the demodulation phase to the maximum sensitivity point is facilitated; the phase noise of a component in a system loop is suppressed, and the signal-to-noise ratio of the system is increased.
Owner:ZHEJIANG UNIV
Correction method for phase noise of multi-antenna OFDM system receiving terminal
InactiveCN101478524BSuppress phase noiseImprove performanceMulti-frequency code systemsMultiple carrier systemsPhase noiseSignal on
The invention relates to a correction method of phase noise at a multi-antennae Orthogonal Frequency Division Multiplexing (OFDM) system receiving end belonging to the wireless data-transmission field. The method places a pilot OFDM symbol every a plurality of data OFDM symbols. In the pilot symbols, the receiving end obtains a channel matrix of the current symbol as a reference channel matrix ofsubsequent data symbols according to a receiving signal on a pilot sub-carrier and the receiving end pilot. In the data symbols, the receiving end obtains the channel matrix of the current symbol according to the receiving signal on the pilot sub-carrier and a reservation signal at the receiving end and obtains a united matrix of a transceiving phase noise mean values by comparing the channel matrix with that of the pilot symbol. According to an estimate value of the transceiving phase noise mean values which are separated from the united matrix, a detection matrix is adjusted. The method cansimultaneous estimate and correct the phase noise of the transmitting and receiving antennas, and improve the system performance.
Owner:TSINGHUA UNIV
Phase noise suppression method and device for remote optical fiber interference system with spectral line operation
ActiveCN103727966BSuppress phase noiseReduce phase noiseConverting sensor output opticallyPhase noisePhase difference
The invention relates to an optical fiber sensing technology and provides a method and device for phase noise suppression of a remote optical fiber interference system in spectral line operation. The device comprises a narrow linewidth single frequency laser, a first electro-optic phase modulator, an erbium-doped optical fiber amplifier, a transmission optical fiber, a second electro-optic phase modulator, an optical fiber Michelson interferometer, a photoelectric detector and a signal collecting and processing device. The method comprises the steps of applying modulating signals at the input end of the transmission optical fiber through the electro-optic phase modulators to generate multifrequency laser, utilizing the modulating signals of the electro-optic phase modulators again at the output end of the transmission optical fiber to recover the multifrequency laser generated by modulation to single frequency laser, simultaneously enabling phase difference between the two modulating signals to be odd number times of pi, and enabling the two modulating signals to have identical frequency and amplitude. The two electro-optic phase modulators are utilized to achieve recoverable spectral line operation, an SBS is suppressed, system phase noises are reduced, and accordingly maximum input power and the sensing distance of a sensing system are improved.
Owner:NAT UNIV OF DEFENSE TECH
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