31results about How to "Low signal to noise" patented technology

The invention relates to a mixed sound signal separation method and device, electronic equipment and a readable medium. The method includes: extracting mixed sound characteristic data from mixed soundsignals; inputting the mixed sound characteristic data into a mixed sound coding module to obtain a first hidden variable and a second hidden variable, wherein the first hidden variable represents human voice characteristics, and the second hidden variable represents accompany sound characteristics; inputting the first hidden variable and the second hidden variable into a human voice decoding model and an accompany sound decoding model to obtain human voice characteristic data and accompany sound characteristic data; acquiring human voice and accompany sound on the basis of the human voice characteristic data and accompany sound characteristic data. The human voice and the accompany sound obtained according to the method is low in signal-to-noise ratio.

The invention discloses a radar adaptive beam forming method based on oblique projection filtration. The method comprises the following steps: (1) signals received by N array elements in an array are set to be x(t), and interference and noise are included; a covariance matrix Rxx for the signals x(t) received by the N array elements is built, eigenvalue decomposition is carried out on the matrix, and interference signal subspace UJ and noise signal subspaceUn are obtained; (2) an interference judgment rule is built, and signal subspace Em for main lobe interference and signal subspace for side lobe interference are determined respectively in the interference signal subspace UJ; (3) an oblique projection operator B is built to carry out oblique projection filtration treatment on the signals x(t) received by the N array elements, signals y(t) after oblique projection filtration treatment are obtained, and a covariance matrix Ryy is built; (4) noise in the covariance matrix Ryy for the signals y(t) after oblique projection filtration treatment is corrected, and a covariance matrix R after correction is obtained; and (5) according to the covariance matrix R after correction, adaptive beam forming is carried out on the signals x(t) received by the N array elements, and signals z(t) after adaptive beam forming are obtained.

The invention discloses a method for estimating a high-accuracy arrival direction without knowing an information source number. Time smoothing processing is carried out on data received by an antenna array by setting K different time smoothing intervals to built K space-time autocorrelation matrixes; a final combined space-time autocorrelation matrix and a spatial spectrum function of arrival direction estimation are calculated; spectrum peak searching is carried out on the spatial spectrum function by gradually changing the searching direction, and then the information source number and the arrival direction are estimated. By means of the method for estimating the high-accuracy arrival direction without knowing the information source number, the arrival direction of signals is estimated without estimating the information source number in advance or carrying out characteristic decomposition on the autocorrelation matrixes of the received signals. Thus, the method is high in reliability, small in workload and easy to achieve through hardware, and makes application of arrival direction estimation to an actual system possible.

The invention discloses a method, a device and a system for data transmission, which belong to the technical field of data communication. The data transmission device comprises a processing unit and a transmitting unit, wherein the processing unit is used for generating a data frame according to to-be-transmitted data, the data frame sequentially comprises a low rate (LR) preamble, a basic preamble, a high efficiency wireless local area network (HEW) preamble and a data part, the LR preamble comprises a low rate short training field (LR-STF), the LR-STF comprises at least two first symbols arranged in a time domain, the content of each first symbol is the same, the period of a time domain waveform corresponding to the first symbol is 1.6 microseconds, and the LR-STF is used for timing synchronization; and the transmitting unit is used for transmitting the data frame to a receiving end. Thus, the problem that the reliability of data frame transmission is poor is solved, the data frame transmission reliability is improved, and the method, the device and the system of the invention can be used for data transmission.

The invention discloses a quadrature reflection index modulation method of an intelligent reflection surface auxiliary wireless communication system. The quadrature reflection index modulation methodcomprises the following steps: S1, carrying out quadrature reflection modulation on information by grouping element units of an intelligent reflection surface; S2, establishing index modulation with the receiving antenna serial number as an index resource; S3, determining the optimal reflection phase shift of each group of elements of the intelligent reflection surface; S4, selecting an orthogonalscheme of the two paths of signals after orthogonal reflection index modulation; and S5, demodulating the sent information at a receiving end. According to the operation of grouping the intelligent reflection surface element units, a certain bit of information can be additionally transmitted; wherein an orthogonal scheme of index modulation taking the receiving antenna serial number as an index resource and selecting two paths of modulated signals is established, so that the bit error rate of the system can be reduced under the condition of relatively low signal-to-noise ratio, and thus the spectral efficiency of the communication system is improved.

High-frequency coil arrangement for a magnetic resonance tomography apparatus and magnetic resonance tomography apparatus employing such an arrangement have a surface coil and a loop coil for enclosing the examination subject. Both coils are fashioned for receiving the same first polarization component. A switching device is present for alternately deactivating and/or activating the surface coil and the loop coil. The two coils are preferably arranged on a common carrier structure that is bendable.

The embodiment of the invention discloses a method, a device and a system for preventing eavesdropping and stealthy recording in a conference. The method comprises any one or more of the following steps: transmitting N first sound wave signals in an omnibearing manner, wherein for each first sound wave signal, the first sound wave signal is obtained by performing frequency modulation on a specificsignal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold, and N is an integer greater than or equal to 1; directionally transmitting asecond sound wave signal to one or more than one audio collector in the X audio collectors of the conference, wherein the frequencies of the first sound wave signal and the second sound wave signal are the same, and are in a frequency band which cannot be perceived by human beings, the second sound wave signal is obtained by performing frequency modulation on the reverse sequence, the reverse sequence is obtained according to N specific signal sequences, and X is an integer greater than or equal to 1. According to the embodiment of the invention, the confidentiality of conference content is improved.

The invention discloses a glass-micropipe-based single nanopore sensor which comprises a glass micropipe, a single nanopore, two fluid chambers, a first voltage source, two Pt electrodes, an ammeter and a second voltage source, wherein the glass micropipe is provided with a protuberance at one end; the single nanopore is arranged in the protuberance; the two fluid chambers are respectively arranged at both ends of the single nanopore and connected with each other through the single nanopore; the first voltage source is used for applying voltages to the two fluid chambers; the two Pt electrodes are arranged on the protuberance and arranged at the upside and downside of the single nanopore; the ammeter is used for detecting voltage between the two Pt electrodes and both ends of the ammeter are respectively connected with the two Pt electrodes; the second voltage source is used for applying voltage to the two Pt electrodes; and the single nanopore and the fluid chambers are all provided with electrolyte. The sensor provided by the invention uses four electrodes to obtain radial current and axial current, so that the sensor disclosed by the invention can have higher sensitivity. Meanwhile, the method disclosed by the invention is simple and can greatly reduce the manufacturing cost of the sensor.

The invention provides a fluorescent probe for tumor diagnosis and treatment as well as a preparation method and an application of the fluorescent probe. In the fluorescent probe, an azacyclo structure base is taken as an H<+> receptor, a near infrared fluorescent dye with high extinction coefficient and tumor targeting effect is taken as a fluorophore, then the OFF-ON type probe capable of regulating fluorescence intensity by rapid PET (photoinduced electron transfer) process is formed, fluorescence of the probe is strengthened in a slightly acidic environment of tumor, tumor detection is realized, the probe has strong PA (photoacoustic) signals at the tumor while fluorescence imaging is performed, and tumor boundary can be determined accurately by NIRF/PA bimodal imaging. The fluorescentprobe also has good photo-thermal treatment effect on the tumor and can be used for preparing corresponding tumor treatment drugs.

The invention discloses a prestack seismic texture analysis method based on a gradient co-occurrence matrix. The method comprises the following steps of S1, acquiring four-dimensional data V to be analyzed from prestack seismic data D; S2, defining a gradient computation direction (formula) and defining a four-dimensional sub-data set (formula); S3, establishing a four-dimensional sub-data set S with the size of T*NI*NC*No by taking a line (:, i, j, k) formed by T sample points in the V as the center, and computing the gradient of each point in the S in sequence in order to obtain a gradient matrix M; and S4, constructing a gradient co-occurrence matrix G based on the gradient matrix, and computing texture feature attributes based on the gradient co-occurrence matrix G. On the basis of a gray level co-occurrence matrix, gradient information is added, and some statistical quantities are extracted from the gradient co-occurrence matrix to reflect the textural features, and the texture analysis method has the advantages that the signal resolution is improved, and the noise influence is reduced.

The invention provides a preparation method and application of a PVC-carbon paste modified electrode for lead ion detection. The electrode can directly adsorb Pb <2+> in tap water, and PVC in the electrode can be used as a binding material and an enriching agent for Pb <2+>. The electrode has the advantages of wide linear range, low detection limit, good reproducibility, strong anti-interference performance and the like, and can be directly used for detecting Pb <2+>. The linear range of the electrode for measuring the lead ions is 2.0 * 10 <-5>-1.0 * 10 <-7> mol/L, and the detection limit is5.0 * 10 <-8> mol/L.

The invention provides a nanochannel with a nanocage structure. The nanochannel comprises a top SiN film layer, a middle SiO2 interlayer and a bottom SiN film layer which form a sandwich structure, wherein a small nanopore with area slightly larger than the maximum sectional area of antigen to be detected and smaller than the minimum sectional area of antibody to be detected is machined on the top SiN film layer, a large nanopore with diameter larger than that of the small nanopore is machined on the bottom SiN film layer and located at a position aligned with the small nanopore in the axial direction, and SiO2 between the small nanopore and the large nanopore is corroded into a hollow nanocage structure; two liquid bath units filled with ionic solution are connected to the two ends of the nanochannel with a nanocage structure, and the antigen and the antibody are added into the same liquid bath next to the small nanohole. When ionic current change is detected under both forward and reverse voltage, it is concluded that specific binding of the antigen and the antibody is not achieved. When ionic current change is detected under forward voltage only, it is concluded that specific binding of the antigen and the antibody is achieved, and then identifying detection of antigen or antibody molecules can be achieved.

The invention discloses a brain-computer interface communication device. According to the brain-computer interface communication device, the whole performance and the reliability are improved, and theproblems that a collected and detected electroencephalogram signal is very weak and is inevitably blended with various noises, the signal to noise ratio of the data is relatively low, and therefore,the signal communication needs to be realized by virtue of a reliable technique are solved. The brain-computer interface communication device comprises a brain module, a receiving module and a brain-computer connector.