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.

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 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.

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 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 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.