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2388 results about "Phase compensation" patented technology

Phase Lead Compensation. A system which has one pole and one dominating zero (the zero which is closer to the origin than all over zeros is known as dominating zero.) is known as lead network. If we want to add a dominating zero for compensation in control system then we have to select lead compensation network.

Continuous variable quantum key distribution system and phase compensation method thereof

The invention relates to a continuous variable quantum key distribution system and a phase compensation method thereof. The method comprises the following steps that: a sending end determines to send a phase compensation frame and determines a value of frequency A in an insertion signal of the phase compensation frame; the sending end sends the phase compensation frame and receives (A-1) signal frames; a receiving end samples an output signal of a coherent detector and extracts the phase compensation frame; the receiving end calculates a voltage value to be compensated according to the phase compensation frame, compensates the compensated voltage value to (A-1) key frame phases through a second phase modulator to eliminate environment and system noises and stores compensated (A-1) key frames into an original key file; the receiving end receives the subsequent phase compensation frame, extracts the phase compensation frame, and repeatedly performs the operation; and the sending end sends an interrupt transmission signal, and after receiving the interrupt transmission signal, the receiving end stops receiving, so key distribution is finished. The invention has the advantages of low bit error rate and reliable communication.
Owner:SHANGHAI JIAODA INTELLECTUAL PORPERTY MANAGEMENT CO LTD +1

Broadband wireless sensor network transmission scheme based on collaborative communication of amplification forward single node

The invention discloses a broadband wireless sensor network transmission scheme based on amplify-and-forward single-node cooperation communication. The scheme is as follows: a source node is firstly used to make an orthogonal space-frequency coding to an original signal, two time slots are respectively used to transmit orthogonal signal frames, then a pilot frequency is inserted and coded signals are subject to IFFT operation to fight against the multi-path attenuation, the coded signals are converted onto a time domain, and the serial data flow is broadcast and sent after the insertion of a cyclic prefix and a training sequence. A first time slot relay node receives signals of the source node, makes frequency deviation and phase compensation, then adopts an amplify-and-forward protocol to synchronously send the processed signals to an information sink node at a second time slot and the source node; an information sink receiver receives a mixed signal from two independent channels, firstly detects a frame head of the signal of the second time slot, then synchronizes with the frame head, then carries out FFT operation to the signal part, converts the signal back to the frequency domain, and performs space-frequency decoding to obtain an original sending symbol. The scheme is simple and easy to operate, can effectively improve the error code rate performance of the system, has strong practicability, and is convenient for the realization of the hardware.
Owner:JIAXING WIRELESS SENSOR NETWORKS CENT CAS

Calibration method for phase measurement, device and distance measuring apparatus

The invention is applied to the field of electro optical distance measurement and provides a calibration method for phase measurement, a device and a distance measuring apparatus. The method comprisesthe following steps: a first lightwave emission device emits a first lightwave to a measured object, the first lightwave is reflected by the measured object and received by a receiving device, and the lightwave acting as an outer light path signal is generated by modulating a first high-frequency oscillator signal; a second lightwave emission device emits a second lightwave to the receiving device, and the lightwave acting as a substrate reference of an inner light path signal is generated by modulating a second high-frequency oscillator signal; and the receiving device carries out phase comparison of the two paths of lightwaves received one after the other and outputs signals with substrate elimination. The invention realizes phase compensation and calibration and avoids inducing uncertain phase noise to circuits because of environment variation, thereby improving the measurement precision of laser ranging, reducing the effect of environment factor to ranging error, reducing the costof a system and enhancing the application of laser ranging to various industries.
Owner:SHENZHEN MILESEEY TECH

Micro movement pulsed radar system and method of phase noise compensation

A pulsed radar system uses phase noise compensation to reduce phase noise due to drift of the reference oscillator to enable detection of micro movements and particularly human motion such as walking, breathing or heartbeat. The noise level due to A / D sampling must be sufficiently low for the phase noise compensation to be effective. As this is currently beyond state-of-the-art for high bandwidth A / D converters used in traditional receiver design, the receiver is suitably reconfigured to use analog range gates and narrowband A / D sampling having sufficiently low noise level. As technology continues to improve, the phase compensation techniques may be directly applicable to the high bandwidth A / D samples in traditional receiver designs. Whether phase compensation is applied to traditional receiver designs or a receiver configured with analog range gates, the steps are essentially the same: data is processed to position a reference range bin (either an analog range gate or a particular time sample) on a stationary reference and the phase variation of that reference range bin is used to compensate the phase of target data in range bins (either an ensemble of range gates or other time samples) near the stationary reference. This effectively moves the radar system and particularly the reference oscillator to the stationary reference thereby greatly reducing oscillator drift and phase noise and decoupling the stand-off range from the level of phase noise.
Owner:RAYTHEON CO

Measuring method and measuring apparatus of subsynchronous and supersynchronous harmonic phasors

The invention discloses a measuring method and measuring apparatus of subsynchronous and supersynchronous harmonic phasors. The method comprises the following steps: acquiring electrical signals so as to generate digital signals; performing filtering processing on the digital signals so as to obtain initial subsynchronous harmonic waves and/or supersynchronous harmonic waves; performing harmonic wave adaptive detection through DFT or FFT so as to obtain an initial frequency; according to the initial frequency, designing a filter so as to extract each subsynchronous harmonic wave and/or each supersynchronous harmonic wave; carrying out correction calculation by use of the phasor correction measuring algorithm so as to obtain the frequency, the amplitude and the phase of corresponding harmonic waves; and according to the gain and phase shift of the filter, performing amplitude compensation and phase compensation on the phasors so as to obtain a three-phase phasor of each subsynchronous harmonic wave and/or each supersynchronous harmonic wave. The measuring method provided by one embodiment of the invention can accurately measure the phasors of the subsynchronous and supersynchronous harmonic waves, thereby being applied to wide-area dynamic monitoring, analyzing, control and protection of subsynchrono resonance/oscillation of a power system.
Owner:TSINGHUA UNIV

Method and apparatus for suppressing power frequency common mode interference

A method and an apparatus for suppressing power frequency common mode interference which are used in a bioelectrical signal measuring system comprising a common mode interference signal extracting circuit and a driving circuit connected to the extracting circuit are provided. The driving circuit changes a phase of a common mode interference signal and amplifies the common mode interference signal, so as to output two-way amplified signals, wherein one amplified signal is selectively outputted to a living body on examination. In particular, the apparatus further includes phase compensating and processing means for receiving both a bioelectrical signal from the living body on examination and the other amplified signal outputted from the driving circuit, determining a phase compensation amount of the other amplified signal outputted from the driving circuit according to a characteristic value of the power frequency interference in the bioelectrical signal so as to phase-compensate the other amplified signal outputted from the driving circuit, and selectively outputting the phase-compensated amplified signal to the living body on examination. The method for suppressing power frequency common mode interference comprises the following steps of: receiving a bioelectrical signal from a living body on examination by phase compensating and processing means; analyzing the characteristic of the bioelectrical signal and determining a phase compensation amount by the phase compensating and processing means; performing a corresponding time delay processing on an amplified signal outputted by the driving circuit; and providing the delay signal to the living body on examination. According to this invention, the capability of the circuit for suppressing power frequency common mode interference is getting improved, and the stability of the analog circuit system and the phase-frequency characteristic of the circuit are maintained. This contributes to the improvement of the quality of the sampled bioelectrical signals.
Owner:SHENZHEN MINDRAY BIO MEDICAL ELECTRONICS CO LTD

Seismic wave absorption and attenuation compensation method

The invention relates to a seismic wave absorption and attenuation compensation method, and belongs to the geophysical exploration data processing technology. The method comprises the following steps: selecting one of VSP (vertical seismic profiling) initial data as reference data, carrying out generalized S-transform on the reference data, selecting sampling points as reference points, and recording the time and time-frequency spectrums of the sampling points; carrying out generalized S-transform on data of each sampling point, and dividing the time-frequency spectrum of corresponding frequency in the time-frequency spectrums of the reference points by the time-frequency spectrum of each sampling point so as to obtain an absorption and attenuation curve; determining a natural logarithm to figure out a phase compensation operator according to a formula of frequency difference of absorption and attenuation signals in a time frequency domain; and carrying out absorption and attenuation compensation and phase compensation in the time frequency domain to obtain a fine VSP wave field profile. The method has the advantages that noise can be eliminated during the process of fitting the absorption and attenuation curve; generalized S-inverse transform without energy loss is realized; signal-to-noise ratio and resolution of the data are improved after compensation; log resolution control is realized; the reference points are selected flexibly; and algorithm is simple and efficient.
Owner:BC P INC CHINA NAT PETROLEUM CORP +1
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