41 results about "Channel signal to noise ratio" patented technology

A-priori performance measures of a wireless communication system, combined with channel signal to noise ratio and / or signal to interference and noise ratio (SNR / SINR) measurements, are used to determine transmission modulation rate to help optimize real-time streaming. The method and apparatus minimize packet error rates (PER) without actually measuring packet error rates. Instead the receiver measures SNR / SINR and the transmitter uses this measured SNR / SINR data along with information about PER vs. Modulation vs. SNR / SINR to adjust the transmission rate.

The invention relates to a device and method for realizing broadband digital magnetic resonance radio frequency receiving. The device comprises a radio frequency receiving signal conditioner, a clock phase jitter suppressor, a high-speed analog to digital converter and a digital down converter, wherein the radio frequency receiving signal conditioner conducts front-end voltage amplification and anti-aliasing filtering for a magnetic resonance signal received by an external device; the clock phase jitter suppressor is used for suppressing phase jitter of a system clock and providing a high-stability clock source in a picosecond or femtosecond order of magnitude for the high-speed analog to digital converter and the digital down converter; the high-speed analog to digital converter is used for realizing digitalized conversion of the radio frequency receiving signal; and the digital down converter is used for conducting orthogonal coherent detection, filtering and frequency down conversion for data output by the high-speed analog to digital converter to obtain broadband data, of a real part and an imaginary part, to be output to the external device. The device can ensure higher channel signal to noise ratio, realizes orthogonal coherent detection and conducts accurate control for nuclear magnetic resonance signal receiving phases. In the process of applying a direct oversampling or undersampling technology, the device can ensure good receiving channel signal to noise ratio and has good instantaneity.

Noise in a receive path of a radio frequency identification (RFID) reader is reduced by using a phase shifter. By reducing the noise, the signal-to-noise ratio (SNR) in the receive path of the RFID reader is improved, thereby increasing the number of RFID tags that can be read in a noisy environment over time and / or improving the capability to distinguish a return signal of the RFID tag(s) from noise. The phase shifter adds a phase shift to a reflected signal and a leakage signal, or to a local oscillation signal.

A source-channel combined coding method including: determining whether a channel signal-to-noise ratio (SNR) is varied or not; when it is determined that the channel SNR is varied, selecting a MODCOD suitable for the channel SNR by referring to a first table defining an SNR threshold value at which data transmission is performed without an error, for each MODCOD designating a low density parity check (LDPC) code rate and a modulation scheme; calculating a source coding rate by using an effective information bit rate of the selected MODCOD; extracting network abstraction layer (NAL) units for each layer from an inputted video frame so as to satisfy the calculated source coding rate, and packetizing the extracted NAL units; binding packets to configure a baseband (BB) frame; and LDPC coding and modulating the BB frame through the code rate and the modulation scheme which are designated by the selected MODCOD.

The invention provides a radio-frequency receiving device for a magnetic resonance fiber spectrograph. According to the radio-frequency receiving device, a signal adjusting unit comprises at least two signal adjusting subunits for adjusting received radio-frequency signals. The input end of each analog-to-digital (AD) converter is connected with the output of a signal adjusting subunit. A signal processing unit comprises at least two digital down-converters for performing down-conversion on the output signals of the AD converter and a parallel processing controller, wherein the parallel processing controller is used for performing parallel processing on the signals output by at least two digital down-converters and transmitting scanning sequence information received from a console to a scanning control unit. A parallel processing controller, each digital down-converter and each AD converter carries out clock control through reference clock signals received by a clock interface of the scanning control unit. By using the radio-frequency receiving device, the bandwidth utilization rate of a digital fiber link and the signal-to-noise ratio of a receiving channel of a radio-frequency receiving unit can be improved.

The invention discloses a two-way multi-order related detection method for a dual-polarization weather radar. The method comprises the following steps: obtaining I / Q (in-phase / quadrature) data of an H (horizontal) channel and a V (vertical) channel; calculating the coherent integration quantities of the H channel and the V channel; calculating the zero-order self-correlation, first-order self-correlation and zero-order cross-correlation quantities of the H channels and the V channels; calculating the weight sum of the multi-order correlation quantity; comparing the weight sum with a threshold value, judging if a weather echo is generated, and if so, calculating the signal-to-noise ratio of the H channel; calculating reflectivity factors under different signal-to-noise ratios; and controlling the quality according to the reflectivity factors, and outputting results. According to the method, the weight sum of the multi-order correlation quantity is introduced in combination with horizontal and vertical polarization echo signals to change a conventional method which simply takes the signal-to-noise ratio of the H channel as a detection factor so as to achieve the purposes of reducing the background noise power and increasing the weak signal detection level, and reduce the loss of the signal-to-noise ratio of an echo wave in a double-transceiver mode.

The invention discloses a modulation and demodulation method and device for a GFDM signal. The modulation method comprises the following steps: carrying out channel coding on a binary signal to be transmitted, and carrying out grouping mapping to obtain a multi-system symbol; generating a corresponding ZC cyclic shift keying sequence after cyclic shift of the primitive ZC sequence according to the multi-system symbol; taking the ZC cyclic shift keying sequence as a spread spectrum code string, and adopting CCSK to carry out spread spectrum on binary data; carrying out serial-parallel conversion on the spread spectrum data to generate data blocks, and enabling column vectors of the data blocks to be a column of ZC cyclic shift keying sequences; taking the column vector of the data block as a sub-symbol of the GFDM; according to the primitive ZC sequence and the corresponding cyclic shift value, obtaining an IDFT form of the sub-symbol; and performing cyclic shift filtering on the IDFT form of each sub-symbol, and performing superposition to generate a baseband signal waveform. Aiming at the characteristics of low channel signal-to-noise ratio, large signal path fading, sensitivity to a signal peak-to-average power ratio and the like in satellite communication, the PAPR of a transmission signal is reduced, and the anti-interference performance is improved.

One embodiment relates to a computer-implemented method that selects one of at least three procedures to determine equalization settings jointly for a transmitter and a receiver. A first process may be used if the end-of-channel signal-to-noise ratio (SNR) is greater than an SNR threshold and the equalization capability of the transmitter is greater than the equalization capability of the receiver. A second process may be used if the end-of-channel SNR is greater than the SNR threshold and the equalization capability of the transmitter is less than the equalization capability of the receiver. A third process may be used if the end-of-channel SNR is less than the SNR threshold. Other embodiments and features are also disclosed.

The invention provides an uplink OFDM system subcarrier and power distribution method and system. The method comprises the following steps: the fairness weight of each user in a cell, the maximum power constraint information and the channel signal-to-noise ratio of each user on a corresponding subcarrier are acquired; a hybrid variable optimization problem is established according to each fairness weight, the channel signal-to-noise ratio and the maximum power constraint information; iterative calculation is performed on the subcarrier distribution information and power configuration information according to the hybrid variable optimization problem; and distribution is performed on the subcarriers and the power separately according to the result of the iterative calculation. According to the invention, subcarrier and power distribution can be performed fast and effectively.

The invention relates to a control method and system for filtering out power frequency interference signals. The control method comprises the steps of firstly rectificating an electrocardiosignal of apreset section of each channel; and then obtaining frequency, range and phase of the rectificated power frequency interference signals of the electrocardiosignal of the preset section, according to signal-to-noise ratio of each channel, obtaining the optimal power frequency interference signals of a system through weighting and estimating the frequency and the phase, and establishing sine waves by combining with the range of each channel; finally conducting subtraction treatment on the preset section of the electrocardiosignal and the reestablished sine wave signals, and accordingly obtainingthe electrocardiosignal without the power frequency interference. Therefore, the effect of filtering out the power frequency interference signals is achieved, ringing effect is not generated, so thatmeasurement is more accurate, and therefore the problem of signal distortion caused by the ringing effect generated due to using a wave trap in the existing filtering technology is solved.

The invention provides a compressed sensing-based dynamic double-arm multichannel staring spectral imaging system. With the system adopted, the problems of large size, large weight, incompactness, lowsingle-channel signal-to-noise ratio and large data volume of an existing double-waveband spectral imaging technology can be solved. The system comprises an objective lens, a digital micro-mirror array, a first subsystem, a second subsystem and a data processing unit; a target light beam is imaged at a primary image plane position through the objective lens; the digital micro-mirror array is usedfor encoding the primarily-imaged image; the digital micro-mirror array is overturned according to a randomly-generated encoding matrix; when the micro-mirrors of the digital micro-mirror array are overturned by +12 degrees, the light beam enters the first subsystem; when the micro-mirrors are turned over by -12 degrees, the light beam enters the second subsystem; each of the first subsystem andthe second subsystem comprises a lens group and a detector, wherein the lens group comprises a collimating lens, a dispersion element and an imaging lens which are arranged in sequence; the detectorsof the two subsystems are area array or linear array detectors with different wave bands; and the data processing unit decodes signals received by the detectors.

The invention discloses a video image transmission method which is used for transmitting visual information mainly depending on gradient sampling data under the assistance of a small amount of low frequency coefficients. The gradient sampling data are generated from gradient data by random projection. Compared with the manner of directly transmitting the gradient data, the manner of transmitting the gradient sampling data provided by the invention can obviously reduce the transmission data size, and can adapt to the situation that the channel bandwidth is insufficient. The video image transmission method disclosed by the invention not only has the advantages of having no cliff effect of SoftCast and being able to simultaneously serve a plurality of clients under different channel conditions, but also can achieve a better visual effect, and can adapt to different channel signal-to-noise ratios and bandwidth environments.

A source-channel combined coding method including: determining whether a channel signal-to-noise ratio (SNR) is varied or not; when it is determined that the channel SNR is varied, selecting a MODCOD suitable for the channel SNR by referring to a first table defining an SNR threshold value at which data transmission is performed without an error, for each MODCOD designating a low density parity check (LDPC) code rate and a modulation scheme; calculating a source coding rate by using an effective information bit rate of the selected MODCOD; extracting network abstraction layer (NAL) units for each layer from an inputted video frame so as to satisfy the calculated source coding rate, and packetizing the extracted NAL units; binding packets to configure a baseband (BB) frame; and LDPC coding and modulating the BB frame through the code rate and the modulation scheme which are designated by the selected MODCOD.

Methods and apparatus for adjusting QAM levels used for providing cloud services to customer premise devices on a per customer premise device basis based on determined communication channel signal to noise ratios. One exemplary method embodiment of providing cloud services to a customer premise device (CPE) includes the steps of: determining a signal to noise (SNR), at a first time, on a first communications channel between a network node and the CPE; selecting based on the SNR a cluster node from a plurality of cluster nodes to use to provide a cloud service to the CPE using a second communications channel, at least a first cluster node and a second cluster node in the plurality of cluster nodes using different Quadrature Amplitude Modulation (QAM) levels to communicate with customer premise devices, and using the selected cluster node to provide the cloud service to the CPE.

The embodiment of the invention provides a method for feeding back a channel signal-to-noise ratio (SNR). The method comprises the following steps of: sending a sub-band average SNR which is equal to the sum of SNRs on data sub-carriers included in a sub-band corresponding to the sub-band average SNR divided by the number of the data sub-carriers included in the sub-band corresponding to the sub-band average SNR; and sending a carrier SNR which is equal to the difference between the SNR on the data sub-carriers included in the sub-band corresponding to the sub-band average SNR and the sub-band average SNR. By adoption of the method, the performance of SNR feedback by feeding back the average SNR in various sub-bands is improved. Meanwhile, the embodiment of the invention also provides a device for implementing the method.

The invention relates to the technical field of communication, in particular to an OFDM (Orthogonal Frequency Division Multiplexing) visible light receiving and transmitting method, system and platform with adaptive transmission amplitude digit compression and a storage medium. By calculating and judging the bit error rate (BER) of the system, the scheme of the invention is provided to realize high-order OFDM visible light communication under a low SNR (Signal to Noise Ratio) and reduce the peak-to-average power ratio (PAPR) of the system at the same time. On the basis of the principle of an amplitude limiting method, intervals with different densities are selected according to the advantages and disadvantages of a channel signal-to-noise ratio (SNR) to carry out amplitude bit compressionon a time domain OFDM signal, so that high-order modulation communication is met under the condition of low SNR in an actual environment. The method is improved based on a traditional amplitude limiting method, the calculation complexity is low, the system device performance requirement can be effectively reduced, the requirement for real-time visible light communication is met, the tolerance degree of a high-order modulation system to low SNR can be remarkably improved, and compared with a traditional method, the performance requirement for a hardware circuit is reduced in an actual system.

The invention relates to a single-end evaluate method with asymmetry digit user line support ability, wherein the invention is characterized in that: the foreground operator provides the program with needed tested line to the wideband test interface; the interface sends it to relative wideband test server, which will automatically pick line via exchanger and control bandwidth tester to test noise signal, frequency response and line length; feeding back the test result to the wideband test server whose single-end discrete modulation algorism software will calculate noise PSD, frequency response curvature, sub channel signal / noise ration and ascending / descending ration, to judge based on the result. The invention can avoid affected by remote user, to apply kinds of normal asymmetry digit service terminals, to evaluate the quality of line.

The invention discloses a short-wave multi-channel multi-bandwidth channel simulation method, including the following steps: (1) inputting characteristic data; (2) inputting an analog signal; (3) sampling the analog signal; (4) obtaining an analytic signal; (5) obtaining mean power; (6) determining whether the mean power is greater than a noise threshold; (7) obtaining a frequency offset-added signal; (8) setting the number of paths; (9) obtaining a multi-path delay signal; (10) obtaining a total fading signal; (11) obtaining a signal-to-noise ratio of each channel; (12) obtaining a noise-added signal; and (13) obtaining an output signal. According to the scheme of the invention, various channel characteristics can be simulated, whether an effective signal input exists can be independentlydetermined, the advantage of simulating different signal-to-noise ratios in different frequency bands can also be realized, and the method disclosed by the invention is suitable for various short-wave communication experiments.

The invention provides a multi-radar joint detection method and device based on a Gaussian kernel. The method comprises the following steps: carrying out square law detection on a plurality of channelecho signals formed by a plurality of radars to obtain a plurality of channel echo signals after detection; setting a fixed value according to the detected echo signals of the plurality of channels;and carrying out Gaussian kernel-based signal fusion detection according to the plurality of channel echo signals after detection and the fixed value so as to determine whether a target exists or not.According to the method, in radar detection, the Gaussian kernel is used for fusing the echo of each channel, so that the fusion accuracy can be greatly improved under the condition that the signal-to-noise ratio of each channel is unknown, and the radar detection performance is improved.

The invention discloses a dual-microphone noise reduction method with an adjustable expected sound source direction, and the method comprises the steps: carrying out the discrete sampling, pre-emphasis, framing and windowing processing of noise signals x1 (t) and x2 (t) received by dual microphones, and obtaining frequency domain signals X1 (omega) and X2 (omega) through short-time Fourier transform; in the beam forming process, a virtual microphone is introduced at the midpoint of a connecting line of the double microphones, differential transformation is carried out on the frequency domain signals X1 (omega) and X2 (omega) according to a central difference format, and differential signals Y1 (omega) and Y2 (omega) are constructed. And calculating statistical average values of power spectrums of the differential signals Y1 (omega) and Y2 (omega), marking a ratio of the statistical average values as a directivity function gamma (omega, theta), analyzing properties of the directivity function gamma (omega, theta), and directly mapping the directivity function gamma (omega, theta) into a noise masking value lambda (omega) through a normalization function. Multiplying the X1 (omega) by the lambda (omega) to obtain a signal R1 (omega) after the noise in the competition direction is eliminated; and a post Wiener filtering process: estimating signal energy and noise energy in the R1 (omega) to obtain a channel signal-to-noise ratio, calculating a gain function, and further eliminating residual noise in the R1 (omega).

The invention relates to an automatic calibration method for a digital-analog hybrid phased-array antenna, and belongs to the technical field of communication. The method is used for calibrating a phased-array antenna system composed of M * N antenna units, and the calibration process is divided into receiving calibration and transmitting calibration. According to the method, the signal-to-noise ratio of the channel can be improved by adaptively adjusting the gain or attenuation of the acquisition channel and the calibration channel, so that the calibration requirement is met, the calibration precision is ensured, the intermediate frequency channel and the radio frequency channel of the digital-analog hybrid phased-array antenna can be calibrated at the same time, and accumulated errors possibly caused by step-by-step calibration are avoided. In addition, by adjusting the emission attenuation and the receiving gain of the calibration channel, a fault channel can be eliminated, so that the system performance is ensured, and the system stability is enhanced.

An improved non-linear processor used in echo cancellation eliminates a comfort noise source (214) and instead inputs a control signal (224) directly into a noise suppression system (403). The noise suppression system (403) uses the control signal (224) to inhibit the iterative update of the background noise estimate when the control signal (224) is active, which prevents any residual echo from biasing the noise estimate provided by the noise suppression system (403). Additionally, the control signal (224) is used by a gain calculator (533) within the noise suppression system (403) to attenuate each frequency band to the maximum allowable amount plus the current residual channel signal-to-noise ratio (SNR). Depending on the implementation, the noise suppression system (403) models the background noise of either a user of the PSTN or a user of a mobile station.

The invention discloses a two-way multi-order related detection method for a dual-polarization weather radar. The method comprises the following steps: obtaining I / Q (in-phase / quadrature) data of an H (horizontal) channel and a V (vertical) channel; calculating the coherent integration quantities of the H channel and the V channel; calculating the zero-order self-correlation, first-order self-correlation and zero-order cross-correlation quantities of the H channels and the V channels; calculating the weight sum of the multi-order correlation quantity; comparing the weight sum with a threshold value, judging if a weather echo is generated, and if so, calculating the signal-to-noise ratio of the H channel; calculating reflectivity factors under different signal-to-noise ratios; and controlling the quality according to the reflectivity factors, and outputting results. According to the method, the weight sum of the multi-order correlation quantity is introduced in combination with horizontal and vertical polarization echo signals to change a conventional method which simply takes the signal-to-noise ratio of the H channel as a detection factor so as to achieve the purposes of reducing the background noise power and increasing the weak signal detection level, and reduce the loss of the signal-to-noise ratio of an echo wave in a double-transceiver mode.

The present disclosure relates to the field of radar signal joint detection, and provides a method and device for grid detection mirror elimination based on centroid search. The method includes: registering each channel radar signal to each spatial grid; calculating the signal noise of each channel of each grid ratio and the sum of signal-to-noise ratio; filter out the target grid array that meets the preset requirements; sort the elements in the target grid array in descending order according to the sum of signal-to-noise ratio; select all grids with the largest sum of signal-to-noise ratio and calculate their centroids ; Save the grid closest to the centroid into the target set, update the echo data of each channel and delete the grid from the target grid array; calculate the signal-to-noise ratio and signal-to-noise ratio of each channel of each grid in the target grid array sum; filter the target grids that meet the preset requirements; determine whether the target grid exists, if so, return to the sorting step, otherwise, the target set contains information as the real target information. The present disclosure can improve the accuracy of mirror image elimination and grid detection accuracy, reduce the number of grids and thus reduce the amount of computation.

The invention provides a noise reduction method and a system based on the analysis of a channel signal-to-noise ratio. The method comprises the following steps: S1, SNR simulation is carried out to separate the contribution amount of crosstalk components contained in the noise; S2, the crosstalk is defined and the signal-to-noise ratio is calculated; 3, set parameters of Tx and Rx, and obtain waveforms of NEXT and FEXT by signal simulation; S4, according to the waveform signal value, the signal line which does not satisfy the signal-to-noise ratio condition is modified again. The embodiment ofthe invention redefines the SNR simulation principle, and includes the situations to be considered in the signal simulation process through two signal simulations, and the signal spectrum and the crosstalk spectrum are expressed in the form of integration, and the signal spectrum and the crosstalk spectrum are extended by half a byte forward and backward with the peak value as the center. Throughthe signal simulation results, the NEXT, FEXT waveform values are expressed concretely, and the signal lines that do not meet the signal-to-noise ratio are modified, so as to reduce the signal noise,and focus on the signal that does not meet the requirements of the management and control.

The invention provides a radio-frequency receiving device for a magnetic resonance fiber spectrograph. According to the radio-frequency receiving device, a signal adjusting unit comprises at least two signal adjusting subunits for adjusting received radio-frequency signals. The input end of each analog-to-digital (AD) converter is connected with the output of a signal adjusting subunit. A signal processing unit comprises at least two digital down-converters for performing down-conversion on the output signals of the AD converter and a parallel processing controller, wherein the parallel processing controller is used for performing parallel processing on the signals output by at least two digital down-converters and transmitting scanning sequence information received from a console to a scanning control unit. A parallel processing controller, each digital down-converter and each AD converter carries out clock control through reference clock signals received by a clock interface of the scanning control unit. By using the radio-frequency receiving device, the bandwidth utilization rate of a digital fiber link and the signal-to-noise ratio of a receiving channel of a radio-frequency receiving unit can be improved.