85 results about "Transmission distortion" patented technology

An apparatus includes a converter separating the OFDM signal into the several sub-carriers, an extraction circuit extracting the reference symbol from at least one of a plurality of sub-carriers, an estimation circuit estimating a transmission distortion channel every the sub-carrier based on the amplitude and phase characteristic of the reference symbol, an adder adding channel estimation results of a first sub-carrier be set at least one of the plurality of sub-carriers, a second sub-carrier adjacent to a high-band side of the first sub-carrier and a third sub-carrier adjacent to a low-band side of the first sub-carrier, a calculator calculating the average of the added value to obtain amplitude and phase correction values with respect to the first sub-carrier, and a correction circuit correcting amplitude and phase with respect to each of the plurality of sub-carriers based on the amplitude and phase correction values.

An OFDM receiver may include OFDM-signal receiving means for receiving an orthogonal frequency division multiplexing (OFDM) signal; channel-characteristic estimating means for estimating a channel characteristic using pilot signals in the OFDM signal received by the OFDM-signal receiving means; and transmission-distortion compensating means for applying, on the basis of the channel characteristic estimated by the channel-characteristic estimating means, processing for compensating for transmission distortion to the OFDM signal received by the OFDM-signal receiving means. The channel-characteristic estimating means may include plural kinds of time-direction-channel estimating means used for the estimation of a channel characteristic, and switching control means for switching these estimating means according to a state of a channel.

The invention discloses an embedded parallel multi-channel digital image acquisition system based on a GigE interface. The embedded parallel multi-channel digital image acquisition system comprises an industrial local area gigabit Ethernet, a camera based on a GigE interface, an industrial computer, and a digital image acquisition embedded device based on a GigE interface. The digital image acquisition embedded device based on a GigE interface is the core device of the system. According to the invention, embedded image multi-channel simultaneous acquisition based on a GigE interface can be realized, and advantages, such as high transmission rate, low image transmission distortion rate, convenient networking, convenient installation, convenient maintenance, etc., can be realized. The digital image acquisition embedded device based on a GigE interface is designed for specially acquiring GigE camera image data in a local area network. Embedded systems developed based on the invention can be widely applied in industrial production field monitoring based on machine vision.

The invention discloses a 3D drawn image objective quality evaluation method based on a stereoscopic vision attention mechanism and structural similarity and relates to the technical field of image quality evaluation. The position relation between an original reference image and a 3D drawn image is obtained in a matching mode through an SIFT (scale-invariant feature transform) model, and multiple concrete distortions such as the compression distortion, the transmission distortion and the drawing distortion are measured through an SSIM model. The stereoscopic vision attention mechanism of a human eye vision system is reflected by drawing a 3D saliency map of the image through calculation, the saliency average value of all SIFT matching windows is worked out to serve as the saliency factor, the saliency factor serves as the weight of each window to perform weighted summation on all SSIM values, and then the final quality evaluation result is obtained. The result shows that the objective quality evaluation method is highly relevant to the subjective feeling.

The invention discloses a monitoring video moving target detection method based on an intra-frame coding compression domain. According to the method, a monitoring video moving target detection method based on the intra-frame coding compression domain is established; the established system comprises an intra-frame residual background frame obtaining module, a moving feature information obtaining and processing module and a moving target obtaining module; intra-frame residual background frames are obtained through the intra-frame residual background frame obtaining module; moving feature information is obtained and processed through the moving feature information obtaining and processing module; and a moving target is obtained through the moving target obtaining module. According to the method, on the basis of the video compression domain, only the intra-frame coding frame residual information needs to be extracted, so the complexity is low and the real-time operability is high; when transmission distortion such as packet loss occurs, the method relatively robust; the moving target is extracted precisely; and the anti-noise capability is high.

The invention discloses a positive and negative voltage dynamic bias level shifting circuit based on negative voltage detection and band-gap references, comprising a power supply voltage detector, an adaptive bias circuit and a level shifting circuit, wherein the power supply voltage detector is used for detecting the negative power supply voltage and positive power supply voltage of a chip, respectively comparing the negative power supply voltage and the positive power supply voltage with a ground level, and outputting a negative power supply voltage signal when the positive power supply voltage reaches a set value and the negative power supply voltage reaches a threshold; the adaptive bias circuit is used for adaptively adjusting bias current according to the negative power supply voltage signal and the power supply voltage; and the level shifting circuit is used for implementing level shifting on a driving signal according to the positive power supply voltage, the negative power supply voltage signal and the bias current to obtain a switch signal which cannot be changed with the power supply voltage and has fixed rising and falling edge delays. According to the positive and negative voltage dynamic bias level shifting circuit disclosed by the invention, the signal transmission distortion caused by power supply voltage changes even the negative voltage can be solved, and thus high reducibility of the signals in a level shifting process under high-speed signal transmission can be improved.

The invention is applicable to the image transmission technology field and provides the method for reducing the image transmission distortion rate on the basis of polarization code attribute. The method comprises steps that A, each pixel of an image is converted into byte bits for arrangement; B, the well-arranged image byte bits are mapped into a polarization code; C, the image byte bits are coded by utilizing the polarization code; D, a bit flow after coding is modulated by utilizing BPSK; E, an image symbol after modulation is transmitted through a wireless simulation channel to a reception end; F, demodulation and continuous-elimination-method decoding for the image symbol are carried out at the reception end by employing the BPSK; G, the image information after demodulation decoding is de-mapped, the image byte bits and the polarization code are separated; and H, the separated image byte bit flow is reconstructed and reduced to form an image. According to the method, unequal protection of the polarization code is utilized, image transmission quality is improved, about 7dB PSNR gain is acquired, and thereby the image transmission distortion rate is reduced.

The invention discloses a design method of a two-dimensional double prototype completely-oversampled DFT (discrete Fourier transform) modulated filter bank. The design of the completely-oversampled DFT modulated filter bank is realized under the condition of near perfect reconstruction. The design problem of two prototype filters is resolved into an unconstrained optimization problem, wherein an objective function is overall distortion of the filter bank, namely, a weighted sum of transmission distortion, aliasing distortion and stopband energy of the prototype filters, and the optimization problem is solved through a double-iteration mechanism according to gradient vectors of the objective function. The computation complexity is remarkably reduced according to equivalent conditions of matrix inversion and a fast algorithm of Toeplitz matrix inversion in single-step iteration. With the adoption of the method, the filter bank with better overall performance can be obtained, the computation complexity is greatly reduced, and the large-scale two-dimensional filter banks can be rapidly designed.

Methods and apparatus for providing improving optical signal transmission results over standard mode fiber using a combination of negative chirp, low extinction ratio, and self-phase modulation transmission techniques in combination are described. The use of pre-transmission signal distortion in combinations with one or more of the other transmission techniques is also described. Pre-transmission signal distortion may be introduced by controlling a modulator with a large symmetric AC signal which causes the modulator to operation in a non-linear region or, alternatively, by using a relatively small non-symmetric AC signal to drive the modulator. Use of the small non-symmetric signal has the advantage of reduced power requirements. The pre-transmission distortion acts to counter some of the distortion introduced by the transmission of the signal over an optic fiber.

The invention discloses a three-dimensional wavelet sub-band sorting and code stream packet sealing method in the telescopic video code, wherein the wavelet sub-band in the time domain is sorted according to the requirement of the sequential decode, and the wavelet sub-band in the time domain is divided into different levels; the wavelet sub-band in the time domain of the same level is sorted according to the size of the transmission distortion MES value; then the code stream after being sorted is packed, then transmitted to a receiving end, when the receiving end does not reach the time limit of the decode, then performs the retransmission when finding the package missing, with the retransmitting time smaller than or equal to the largest retransmitting time; when the receiving end reaches the time limit of the decode, the package missing is not retransmitted. The method provides an effective code rate transmission control method, thereby providing correct code stream distribution for the video code and the transmission, providing the code stream organizing and transmitting way of high performance three-dimensional retractability self-adapting to the isomery, the network bandwidth wave property and the time delay change and the terminal diversity of the user receiving.

The invention provides a semiconductor chip aging test device and method. The device comprises an aging test board and a control circuit having a multiplexer and multiple high frequency crystal oscillators, when a signal input end of the multiplexer is connected with the high frequency crystal oscillators, a signal control end of the multiplexer is in gating connection with the signal input end, a signal output end of the multiplexer outputs a test signal which is loaded to a chip socket, and an aging test on a semiconductor chip is carried out. The device is advantaged in that a disadvantage of medium/high frequency signal transmission distortion in the prior art can be solved, selective input of multiple sets of signals having different frequencies is realized, and test accuracy and test efficiency are improved.

The invention relates to a distortion emulator of a broadcast communication transmitter and a method for detecting distortion correction of the emulator. The emulator simulates distortion models of various transmitters through a linear distortion emulation module and a non-linear distortion emulation module, and detects the performance of system distortion correction. The emulator also comprises a down converter and an up converter processing a radio-frequency signal, so that both a radio-frequency band signal and a digital baseband signal can be processed. The method comprises correction performance testing method of a broadcast communication transmitter and distortion performance testing method of a broadcast communication system anti-transmitter. The method evaluates the correction performance of an exciter and the anti-transmission distortion performance of the communication system by simulating transmission distortion through a distortion emulator. With the device and the method, the performance of the transmitter and a receiver of the broadcast communication system can be evaluated under a laboratory environment. Compared with the traditional experiment method, the complexity degree of laboratory equipment is lowered and experimental costs are reduced.

The invention relates to a video error-resistance coding and encoding method based on embedded distributed video coding descriptions, belonging to the technical field of coding and encoding. The method comprises the following steps: carrying out hybrid predictive video coding at a coding terminal to obtain distributed video coding code stream; carrying out distributed video coding protection processing on interframe encoding frames in the video coding code stream and then transmitting the interframe encoding frames to a decoding terminal; discarding the distributed video coding stream corresponding to the interframe encoding frames when no transmission errors exist in the interframe encoding frames and reference frames are not affected by transmission distortion; or else, encoding the received distributed video coding stream and taking the encoded results as the references for follow-up frames to eliminate transmission of transmission distortion with the passage of time and realize video error-resistance. In the invention, the combined optimization of the distributed video coding and the traditional coding can improve overall performance of the system, so that the method is suitable for video transmission with no feedback channels or longer time delay of feedback channel transmission.

The invention relates to an unequal error transmission protection method based on an H.264 video message type. The unequal error transmission protection method measures importance of various contents of an H.264 video message according to a practical network packet loss environment, establishes a redundancy bandwidth optimization distribution model, adopts linear coding to perform unequal mistake protection on the video stream, uses less bandwidth to realize better code stream protection and effectively reduces transmission distortion of the video.

The invention relates to a method and device for simultaneously measuring the reflection and transmission distortion difference of an optical element. The method comprises the steps: enabling a detection light source to enter a first half-transparent and half-reflecting mirror which is parallel to a to-be-measured sample, enabling transmission light transmitted by the first half-transparent and half-reflecting mirror to serve as detection light, enabling the detection light to enter the to-be-measured sample, and dividing the detection light into reflected light and transmission light, wherein light paths corresponding to the reflected light and the transmitted light are respectively called as a reflecting arm and a transmitting arm, and a light beam on the transmitting arm passes through a first optical path difference adjusting mechanism and a first reflecting mirror and then enters a second semi-transparent semi-reflecting mirror; the light beam reflected by the third semi-transparent semi-reflective mirror enters the second semi-transparent semi-reflective mirror and interferes with the light beam entering the transmission arm of the second semi-transparent semi-reflective mirror, and the light beam is acquired by the first camera and imaged into interference fringes. According to the invention, the deformation of the front surface and the rear surface of the highlight optical element can be quantitatively and reversely deduced on line in real time, the result is accurate, and the optical path difference between transmitted light and reflected light can be measured through a single camera.

The invention relates to a remote asynchronous power frequency signal phase difference measurement method and system. The power frequency signal phase difference measurement method comprises the steps that first phase difference between a first measured power frequency signal and a city power reference signal and second phase difference between a second measured power frequency signal and the city power reference signal are acquired, and phase difference between first and second measured power frequency signals is acquired through first and second phase difference. According to the invention, remote asynchronous phase difference measurement is realized; the problem of inconvenient tow wire construction, which is caused by long distance between two measured signals in engineering application, is solved; defects of long distance signal transmission distortion are avoided; the construction difficulty of the measurement system based on a phase difference technology in the fields of power device state monitoring, signal acquisition and analysis, communication, automatic control and the like is reduced; and the quality of the relevant measurement system and the effectiveness of state determination are improved.

The invention provides an unbalanced resource distributing method for transmitting layered compressed information sources in a COFDM system. The method comprises the steps of resolving the compressed information sources into two sub layers, respectively calculating out a resource distributing scheme and expected reestablishment distortion before the compressed information sources are resolved and a resource distributing scheme and expected reestablishment distortion after the compressed information sources are resolved, comparing the expected reestablishment distortion before the compressed information sources are resolved with the expected reestablishment distortion after the compressed information sources are resolved, storing the resource distributing scheme before the compressed information sources are resolved if the expected reestablishment distortion before the compressed information sources are resolved is smaller than the expected reestablishment distortion after the compressed information sources are resolved, continuing resolving the layered compressed information sources if the expected reestablishment distortion before the compressed information sources are resolved is not smaller than the expected reestablishment distortion after the compressed information sources are resolved, carrying out recursion on the resolving process until unbalanced resource distribution relying on sub layer resolving cannot obtain smaller expected transmission distortion. Based on the divide and conquer (DC) idea, the method can efficiently distribute subcarriers of level-by-level information source bits and power resources and can reduce expected reestablishment distortion of information sources at the receiving end.

The invention discloses a soft magnetic ferrite material with high magnetic permeability. The soft magnetic ferrite material comprises main components and auxiliary components. The main components comprise, by weight, 50.8-53.8 mol% of iron oxide, 25.2-27.2 mol% of manganese oxide and the balance zinc oxide; the auxiliary components comprise at least five of TiO2, CaCO3, Bi2O3, Co2O3, Li2O, ZrO2 and WO3. The soft magnetic ferrite material with the high magnetic permeability has the advantages that the initial magnetic permeability of the soft magnetic ferrite material is higher than 7000 (25 DEG C), variation of the initial magnetic permeability is lower than 13% in the range from -55 DEG C to 85 DEG C, the initial magnetic permeability is higher than 6000 in the range from 10 kHz to 400 kHz, the cutoff frequencies are higher than 5 MHz, the hysteresis constant eta B is lower than 0.2*10<-6> /mT; (in the temperature range of -55 DEG C to 85 DEG C, B1=1.5 mT and B2=3mT), the hysteresisconstant eta B is lower than 0.18*10<-6> /mT at 25 DEG C; ( B1=1.5 mT and B2=3 mT); the soft magnetic ferrite material can be widely applied to communication transformers and network transformers withrequirements on low signal transmission distortion and high high-frequency anti-jamming capacity.

The invention discloses a nonlinear load electric energy metering device which comprises a voltage sensing and conditioning unit, a voltage RC filter circuit, a current sensing and conditioning circuit, a current RC filter circuit, an ADC analog-digital converter and a data processing and managing unit. Voltage signals are transmitted to the ADC analog-digital converter through the voltage sensing and conditioning unit and the voltage RC filter circuit. Current signals are transmitted to the ADC analog-digital converter through the current sensing and conditioning circuit and the current RC filter circuit. The ADC analog-digital converter carries out conversion on the received voltage signals and the current signals and transmits the voltage signals and the current signals to the data processing and managing unit. The nonlinear load electric energy metering device achieves the advantages that metering signal transmission distortion does not occur and work is stable and reliable in the conditions that impact load is wide in frequency band and large in dynamic range.

The invention belongs to the technical field of unmanned aerial vehicles, and discloses a high-altitude flight antifreezing system of an unmanned aerial vehicle. The system comprises heating structures, power supply batteries, a vehicle-mounted controller, a wireless transreceiver module and a ground remote control terminal, wherein the heating structures are connected with the power supply batteries through control switches to obtain electric energy to generate heat, and are distributed on windward sides of wings and empennages of the unmanned aerial vehicle; the control switches are connected with the vehicle-mounted controller to control the power supply of the heating structures; and the vehicle-mounted controller communicates with the ground terminal control terminal through the wireless transreceiver module. The system is provided with the heating structures on the wings and the empennages of the unmanned aerial vehicle to deal with the problem of freezing of the windward surfaces in the high-altitude flight so as to prevent the freezing from influencing the aerodynamic configuration and causing signal transmission distortion; and meanwhile, a remote control communication mechanism is established to realize flexible deicing and antifreezing control and prevent freezing.