311 results about "Frequency selectivity" patented technology

The invention discloses a bionic TENG sensor unit for an artificial throat and a preparation method thereof, and relates to the field of artificial throats, and the sensor unit comprises a gradient micro-dome friction layer, a strain amplification layer, an electrode layer and a back cavity substrate layer. The gradient micro-dome array realizes gradual contact through gradient change of height and diameter; the strain amplification layer converts vertical vibration into horizontal strain by using a cantilever beam-sliding block structure; the back cavity array selectively amplifies vibration at a specific frequency based on the Helmholtz resonance principle. The invention further provides a corresponding preparation method. The preparation method comprises the steps of back cavity forming, electrode deposition, microstructure manufacturing, surface treatment and the like. The sensor has the advantages of high sensitivity, good frequency selectivity and strong durability, and is particularly suitable for detecting weak laryngeal vibration signals of laryngeal patients.

The invention discloses an OCT (Optical Coherence Tomography) retina image denoising method based on a high-frequency enhanced diffusion model, which is characterized in that a double-branch diffusion model network constructed based on frequency perception Fourier transform attention (FFTA) is used for separating different frequency domains, enhancing specific frequency domain features and fusing the specific frequency domain features into a spatial domain feature map to realize stronger frequency domain perception and processing capability; the invention relates to a time step T coding method for a module of frequency domain attention. The time step T of the diffusion model is used as a parameter to be coded into a frequency domain attention module to participate in self-attention matrix calculation, so that frequency domain feature processing is aligned with the iteration step number of the diffusion model, and different frequency domain information is pointedly processed at different time steps T; the frequency selective hopping mechanism uses pooling operation to obtain a high / low frequency characteristic pattern, so that the network has adaptive frequency domain retention capability for different local parts.

The present disclosure provides a frequency selective reflector reflecting electromagnetic waves in a particular frequency band of 24 GHz or more in a direction different from a regular reflection direction, the frequency selective reflector comprising: a reflecting member reflecting the electromagnetic waves; and a dielectric layer that is disposed at an incident side of the electromagnetic waves with respect to the reflecting member and transmits the electromagnetic waves, the dielectric layer has two types of thicknesses, and includes a plurality of first regions with thinner thickness and a plurality of second regions with thicker thickness.

The invention provides an electric connector signal transmission optimization method and system, and relates to the technical field of communication, and the method comprises the steps: obtaining an electrical characteristic parameter and transmission path topological information, recognizing a frequency turning point, calculating a loss coefficient, constructing a frequency selectivity compensation mapping rule, and obtaining a frequency division compensation strategy; and calculating a double-component correction factor, carrying out nonlinear adaptive adjustment to obtain a target compensation parameter, and finally generating a multi-path compensation control signal. According to the invention, loss characteristics in signal transmission can be accurately identified, frequency selective compensation is realized, and the signal transmission quality and stability of the electric connector are improved.

The disclosure deals with system and method for discerning the radius maximizing reliability for binary modulation on conjugate-reciprocal zeros (BMOCZ) implemented with both a maximum likelihood (ML) and direct zero-testing (DiZeT) decoder. The optimal radius for BMOCZ is disclosed to be a function of the employed decoder. The radius maximizing the minimum distance between polynomial zeros does not maximize the minimum distance of the final code. While maximizing zero separation offers an almost optimal solution for the DiZeT decoder, the ML decoder outperforms the DiZeT decoder in both additive white Gaussian noise (AWGN) and fading channels when the radius is chosen to maximize codeword separation. Different sequence-to-subcarrier mappings for BMOCZ-based orthogonal frequency division multiplexing (OFDM) are analyzed to highlight a flexible time-frequency mapping approach that avoids distortion introduced by a frequency-selective channel at the expense of higher peak-to-average power ratio (PAPR).

The invention discloses a broadband millimeter wave magnetoelectric dipole filtering antenna unit and a filtering array, the antenna is realized by adopting a multi-layer printed circuit board, and the antenna comprises a radiation layer printed circuit board and a feed layer printed circuit board. The radiation layer printed circuit board is provided with a magnetoelectric dipole radiator, and an electric dipole patch etched with an H-shaped gap reduces the size of the radiator while achieving low-frequency good filtering. A substrate integrated waveguide (SIW) cavity is arranged around the magnetoelectric dipole radiator, so that surface waves are suppressed, and the overall suppression effect of a stop band is enhanced. A strip line fed by a coaxial probe and a shielding SIW cavity structure are integrated on a feed layer printed circuit board, and the feed structure generates two radiation zero points at high frequency, so that good filtering response is realized. The antenna provided by the invention has the advantages of wide frequency band, small size, high out-of-band rejection level and frequency selectivity.

In a probabilistic amplitude shaping (PAS) system, a distribution matching (DM) component may receive a uniform bit sequence with equal probabilities, which may be converted into symbols with a desired probability distribution (e.g., Gaussian). For example, the probability distribution may use inner constellation points associated with a lower energy and / or power more frequently and outer constellation points associated with a higher energy and / or power less frequently. In general, the DM component may map binary bits to positive amplitudes with a non-uniform distribution according to a DM rate that is based at least in part on a signal-to-noise ratio (SNR), which may vary significantly in a spatial and frequency selective wireless channel. Accordingly, some aspects described herein relate to configuring DM parameters and codeword and resource mappings in a spatial and frequency selective wireless channel.

The invention discloses an elastic wave filter based on an annular cylindrical shell thin plate structure and an implementation method thereof. The elastic wave filter comprises a homogeneous elastic thin plate and a resonance structure of a hollow annular cylindrical shell. By introducing an annular cylindrical shell resonance structure, efficient filtering and frequency selective control of elastic waves are realized. The filter has the advantages of high frequency selectivity, wide bandwidth control, construction flexibility, high reliability and the like, and is suitable for the fields of signal processing, sensing and the like.

The invention discloses a terahertz detector based on a circular metasurface and graphene composite structure and a method, and belongs to the technical field of semiconductor devices and micro-nano machining. The device comprises a substrate, a graphene layer, a circular metasurface layer, a first electrode and a second electrode, the graphene layer is arranged on the substrate; the first electrode and the second electrode are oppositely arranged on two side ends of the graphene layer; the circular metasurface layer is arranged on the graphene layer and located between the first electrode and the second electrode. According to the invention, the local field enhancement effect of the metasurface structure is combined with the photoelectric response of graphene, the frequency selective absorption of terahertz waves is realized, the signal-to-noise ratio and selectivity of the detector are improved, and the sensitivity and response speed of the detector are improved at the same time.

The invention provides a component high-frequency signal transmission quality prediction and optimization method and system, and relates to the technical field of signal transmission, and the method comprises the steps: extracting the attenuation change rate of each frequency band based on the frequency domain characteristics and transmission path physical characteristic parameters of a to-be-transmitted signal of a component, and building a correlation function with a frequency band boundary position; calculating a transmission path terminal prediction loss spectrum and determining a compensation gain coefficient; performing frequency selective amplitude adjustment on the to-be-transmitted signal; and an actual received signal is collected and compared with the target frequency domain amplitude distribution, and the correlation function is updated. According to the invention, accurate prediction and adaptive optimization of high-frequency signal transmission quality are realized, and signal transmission integrity is improved.

The invention discloses a channel prediction method and device suitable for a non-ground network, and relates to the technical field of artificial intelligence, and the method comprises the steps: S1, user equipment located on the ground carries out uplink communication with a gNodeB located on an LEO satellite; s2, the CP-OFDM waveform carrying the resource grid is sent by the user equipment and is propagated through a frequency selective channel; s3, at a receiving end, removing the cyclic prefix from the signal, and performing demultiplexing on the received symbol; and S4, for the estimation value of the CFR matrix, applying least square channel estimation on the received pilot symbol, and performing interpolation in the time slot duration. According to the channel prediction method and device suitable for the non-ground network, channel estimation can be not affected by removing pilot frequency every other OFDM time slot, the uplink peak throughput can be remarkably improved regardless of the data modulation order in most cases, and the performance is hardly affected.

A tuned-frequency-spectrum earpiece for selectively tuning audio frequencies that enter an inner ear of a user wearing the earpiece, the earpiece including a base having an emitter end and receiver end, the base including a channel that passes through an entirety of the base; a sound-attenuation plug, wherein the sound-attenuation plug is configured to couple to the base such that the sound-attenuation plug surrounds at least a portion of the channel of the base; a first filter device configured to insert into the channel of the base and to selectively reject undesired frequencies of the audio frequencies that enter the earpiece; and a frequency-selective sound collector operatively coupled to the receiver end of the base and configured to increase an amount of desired frequencies of the audio frequencies that enter the first filter device. Some embodiments increase the amount of sound from some directions while reducing sound from other directions.

The invention discloses a time-frequency domain joint channel equalization method for a single-carrier NOMA (Non-Orthogonal Multiple Access) system, and solves the problems that a single carrier is poor in frequency selective fading resistance and is not matched with NOMA power multiplexing signals in the prior art. The method comprises the following steps of: at a receiving end of a single-carrier NOMA system, converting a received signal of each frame into a frequency domain by using FFT (Fast Fourier Transform), and carrying out data separation to obtain a section of unique word sequence and an effective data sequence; estimating channel state information in a frequency domain by utilizing prior information and a section of unique word sequence to obtain a channel estimation result corresponding to each symbol, and performing minimum mean square error frequency domain equalization on a section of effective data sequence according to the result to obtain a corresponding frequency domain signal; performing fine adjustment on the corresponding frequency domain signal in the time domain by using a time domain soft decision equalization algorithm of the power distribution factor to obtain an equalized time domain signal; according to the method, more accurate channel compensation is realized, and the decoding performance and the anti-interference capability of the system are improved.

A frequency selective unit, a frequency selective surface, and an antenna base station. The frequency selective unit comprises a metal reflector plate and at least two conductive material pattern layers, wherein through holes are provided in the metal reflector plate, the at least two conductive material pattern layers run through the through holes, and there is a gap between the conductive material pattern layers and the metal reflector plate; and at least one conductive material pattern layer comprises a first transmission mode, and at least the other conductive material pattern layer comprises a second transmission mode, and in a transition band, electromagnetic waves in the two transmission modes have opposite phases and cancel each other, such that the electromagnetic waves cannot be transmitted through the frequency selective unit; moreover, an electromagnetic wave transmission zero can be generated in the transition band, and a sharp roll-off is formed at an out-of-band edge of a second band, thereby realizing high-frequency selectivity. The conductive material pattern layers are not parallel to the metal reflector plate, the transmission direction of the electromagnetic waves is parallel to the surfaces of the conductive material pattern layers, and it is not necessary to provide a metallized via hole between the at least two conductive material pattern layers to perform electrical connection, thereby simplifying the manufacturing process and processing difficulty of the frequency selective unit.

The invention discloses a space-time modulation filtering circulator based on a substrate integrated waveguide, which consists of a top metal patch, a dielectric substrate, a bottom metal floor, a large metalized through hole and a small metalized through hole, and comprises a rectangular SIW cavity I, a rectangular SIW cavity II, a rectangular SIW cavity III, a pentagonal SIW cavity I, a pentagonal SIW cavity II, a pentagonal SIW cavity III and a circulator central junction, the rectangular SIW cavities are traditional SIW cavities resonating in a fundamental mode, and the pentagonal SIW cavities are space-time modulation SIW cavities; the pentagonal SIW cavity I, the pentagonal SIW cavity II and the pentagonal SIW cavity III are coupled and cascaded through a circulator central junction; the rectangular SIW cavities I, II and III are cascaded with the pentagonal SIW cavities I, II and III in a magnetic coupling mode; the rectangular SIW cavity I, the rectangular SIW cavity II and the rectangular SIW cavity III are fed by the coplanar waveguide transmission line I, the coplanar waveguide transmission line II and the coplanar waveguide transmission line III; according to the space-time modulation SIW filtering circulator provided by the invention, ferrite materials are not needed, the circulator function is realized by adopting three tuning elements, the design complexity of the space-time modulation circulator is reduced, and the frequency selectivity is improved.

The invention discloses a low-profile low-RCS (radar cross section) circular polarization double-folded transmission array antenna, which comprises a wave-absorbing type frequency selection polarizer and a double-folded transmission array antenna, and is characterized in that the wave-absorbing type frequency selection polarizer is positioned above the double-folded transmission array antenna; the wave-absorbing type frequency selection polarizer comprises a loss layer and a linear circular polarization converter with a frequency selection characteristic, wherein the loss layer and the linear circular polarization converter are separated by an air gap layer; the double-folded transmission array antenna comprises an integrated reflection-transmission metasurface and a polarization conversion metasurface, and the integrated reflection-transmission metasurface and the polarization conversion metasurface are separated by an air gap layer. According to the circularly polarized antenna, the single-station RCS reduction performance of more than 10 dB is achieved within the broadband range of 6.8-21.9 GHz, meanwhile, the radiation gain can be improved, the profile can be reduced, and the circularly polarized antenna has the advantages of being wide in band, low in profile, high in gain and low in RCS.

Wireless communications systems and methods related to wireless communications in a system are provided. A user equipment (UE) may receive from a base station (BS), an uplink (UL) scheduling grant indicating subband precoding information and a resource allocation spanning a plurality of subbands. The UE may determine a plurality of subband precoders based on the subband precoding information. Each precoder of the plurality of subband precoders may be associated with a subband of the plurality of subbands. The UE may transmit to the BS, an UL communication signal in the resource allocation using the plurality of subband precoders.

The invention belongs to the technical field of integrated circuits, and discloses a high-selectivity constant-bandwidth reconfigurable filter chip based on a GaAs (gallium arsenide) process, which comprises a dielectric substrate, a multilayer metal structure, a plurality of folded opening-shaped metal microstrip lines, a plurality of grounding metal columns, a variable capacitance diode, an MIM (metal injection molding) capacitor and the like. Resonance is realized in a mode of combining electric coupling and magnetic coupling, a variable capacitance diode is utilized to tune the center frequency, and the bandwidth is kept constant in the tuning process. Transmission zeros are introduced at two sides of a passband through cross coupling, so that the frequency selectivity and the spectrum management capability are remarkably improved, and meanwhile, the optimization of the microstrip interconnection structure effectively reduces the system loss. According to the invention, the strict requirements of a modern radio frequency communication system on miniaturization, high performance and high selectivity can be met, and extremely high adjustability and adaptability are achieved.

The invention discloses a high-isolation and high-selectivity filtering power divider with an input end broadband non-reflection characteristic. Comprising an input port, two output ports, a double-L-shaped non-reflection absorption structure, two microstrip connecting lines, two parallel coupling lines, two L-shaped step resonators, two non-reflection absorption isolation resistors, a quarter-wavelength parallel coupling connecting line and two U-shaped transmission lines. The input port is a first port; the two output ports comprise a port II and a port III; the double-L-shaped non-reflection absorption structure comprises a first non-reflection absorption resistor, a second non-reflection absorption resistor, a first L-shaped non-reflection absorption connecting line and a second L-shaped non-reflection absorption connecting line. According to the invention, the broadband reflection-free absorption characteristic of the input end and the broadband high isolation between the output ports are realized at the same time, a plurality of transmission zeros are introduced through the L-shaped step resonators, and the frequency selectivity and out-of-band rejection are improved.

The invention discloses a low-voltage power line carrier communication network repeater deployment method and system, and relates to the technical field of power communication. The method comprises the following steps: (1) according to PLC network topology information, acquiring an STA set which cannot directly communicate with a CCO, and inputting model parameters; (2) calling a general optimization solver to carry out model solution to obtain a solution result; (3) if the feasible solution exists, outputting a PCO deployment mark; if not, adjusting the received signal threshold value and the transmitting power, and repeating the step (2); and (5) once a feasible solution is obtained or the model parameter reaches the set limit value, the solution is ended. According to the deployment planning model constructed by the invention, the optimal deployment position of the PCO in the network is solved by taking the minimum weighted sum of the total transmission time delay and the total cost as a target and taking the received signal strength and the single-hop relay as constraints; the problem that seamless coverage of a low-voltage power distribution network is difficult to realize by single-hop communication due to high background noise and frequency selective fading of a PLC channel is solved.

The present invention provides an interleaving method and a related device for mapping a virtual resource block to a physical resource block (VRB-to-PRB) during a sub-band full duplex (SBFD) period, and a method for mapping a virtual resource block to a physical resource block (VRB-to-PRB) during the SBFD period of the sub-band full duplex (SBFD) period of the sub-band full duplex (SBFD) period of the sub-band full duplex (SBFD) period of the sub-band full duplex (SBFD) period of the virtual resource block to the physical resource block (VRB-to-PRB). In one embodiment, the method includes performing a VRB-to-PRB interleaving during the SBFD to interleave resource blocks (RBs) and map a VRB beam to a PRB beam in a first DL frequency domain and a second DL frequency domain. By the method, the VRB-to-PRB interleaving is enhanced in the SBFD operation, thereby being able to benefit from less frequency selective fading.

The invention discloses a coding and decoding method for LDPC codes under time and frequency selective channels in an NAVDAT system, and the method comprises the steps: determining a basis matrix and an expansion factor Z according to an information bit length and a target code length of an input bit sequence before coding, and the Z is a positive integer; obtaining a low density parity check (LDPC) matrix based on the basis matrix and the expansion factor Z; the method comprises the following steps: encoding an input bit sequence by using a low density parity check (LDPC) matrix under an NAVDAT system time and frequency selective channel, wherein the code rate is 3 / 4 or 1 / 2; wherein a basis matrix of the LDPC matrix comprises a sub-matrix A and a sub-matrix B, if the basis matrix is expressed as an m-row n-column matrix, the sub-matrix A is an m-row n-m-column matrix, the sub-matrix B is an m-row m-column matrix, and the sub-matrix B comprises a double-diagonal structure matrix B1, a single-diagonal structure matrix B2 and a column B3 with the weight of 4; and outputting the coded or decoded bit sequence. According to the invention, the coding requirements of information bit sequences with various lengths can be met.

The application provides a design method of a broadband multi-modal vibration suppression damping material based on fractal geometry, comprising: constructing an initial geometric configuration of the damping material, the damping material being composed of a periodic arrangement of a three-dimensional unit cell structure in a plane; layering the unit cell structure to construct a parameterized model of the unit cell structure by using a fractal dimension of the unit cell structure and layer structure parameters; constructing a vibration impedance transfer equation according to the parameterized model of the unit cell structure, determining input impedances of the innermost layer and the outermost layer, and determining vibration attenuation amounts of the unit cell structure in multi-target frequency bands by using the input impedances of the innermost layer and the outermost layer; and optimizing the configuration and the parameterized model of the unit cell structure until the vibration attenuation amounts of the unit cell structure in the multi-target frequency bands meet load platform requirements. The broadband multi-modal vibration suppression damping material based on fractal geometry constructed can realize efficient dissipation of 10-1000 Hz broadband vibration energy and solve the frequency selectivity limitation of traditional homogeneous damping materials in multi-frequency vibration suppression.

The application relates to the technical field of tunable N-path filter, in particular to a tunable N-path reflection-free filter and a superheterodyne receiver. The tunable N-path reflection-free filter comprises a signal source, an N-path band-pass filter unit, an N-path band-stop filter unit, an output resistor and a phase-splitting clock generating circuit. The output end of the signal source is connected with one end of the N-path band-pass filter unit and the N-path band-stop filter unit respectively, the other end of the N-path band-stop filter unit is connected with the output resistor, the gate of a plurality of MOS switches in the N-path band-pass filter unit and the N-path band-stop filter unit is connected with the phase-splitting clock generating circuit, and the phase-splitting clock generating circuit outputs a control signal. The tunable N-path reflection-free filter provided by the application has excellent frequency selectivity, can effectively suppress high-order harmonics, and can adjust the passband and the stopband by changing the switching frequency. Meanwhile, the filter can eliminate the reflected signal, prevent the intermodulation interference and gain fluctuation of the mixer and the high-gain amplifier in the system.

The invention provides an integrated reconfigurable filtering honeycomb super-medium reflective array, which belongs to the field of antennae and comprises a multi-feed horn, a reflective array ground plane and a first transmission network arranged on the surface of one side of the reflective array ground plane in a matrix mode. Reconfigurable filters corresponding to the positions of the first transmission networks are arranged on the surface of the other side of the reflection ground plane, and each first transmission network comprises a honeycomb-shaped transmitting unit T and a honeycomb-shaped receiving unit R. The multi-feed-source horn transmits electromagnetic wave signals to the air. Each receiving unit R receives a signal and transmits the signal to the transmitting unit T through the corresponding reconfigurable filter, each transmitting unit T transmits wave beams outwards, the transmitting unit T can receive the wave beams transmitted by different receiving units R, and performance parameters are set and reflected frequency characteristics are adjusted by adjusting the reconfigurable filters; the invention further provides a honeycomb super-medium transmission array integrated with reconfigurable filtering. The invention also provides a transflective array. And the frequency selectivity and the out-of-band rejection capability of the antenna are improved.

Apparatuses and methods for frequency selective beam management (FSBM). A method for operating a user equipment (UE) includes receiving first information indicating one or more channel state information (CSI) reference signal (RS) resources for FSBM and receiving second information indicating a correspondence between the one or more CSI-RS resources and a plurality of frequency subbands. The method further includes determining, based on the first information, the one or more CSI-RS resources for FSBM and identifying, based on the second information, the correspondence between the one or more CSI-RS resources and the plurality of frequency subbands.

A one-piece optical structure includes a frequency selective reflective structure disposed between a decorative cover layer and a ground metal layer. The ground metal layer is configured to reflect and / or absorb radio frequency electromagnetic waves transmitted by the decorative cover layer and the frequency selective reflective structure. Each of the frequency selective reflective structures includes a frequency selective surface layer disposed on the multi-layer stack and having a set of metal elements that repeat across the frequency selective surface layer to form an array. The integrated optical structure reflects a collimated incident RF electromagnetic wave, which has a wavelength in the range of 1.0 mm to 10 cm and is incident at an incident angle, into a collimated reflected wave at a reflection angle different from the incident angle. The frequency selective reflective structure has an optical transmittance greater than 50% for vertical incident light having a first visible wavelength.

The present invention discloses a frequency-selective nano-TiO2 doped polyurethane sound-absorbing foam and its preparation method and application. The sound-absorbing foam comprises the following components: a matrix material, a functional filler, and a foaming agent. Among them, the functional filler is surface-hydroxylated nano-TiO2 with a content of 1 wt%, the foaming agent is water with a content of 0.4 - 0.9 wt%, and the rest is the matrix material. Through the nano-TiO2 doping and gradient foaming process, the present invention successfully develops a polyurethane sound-absorbing foam with frequency selectivity, which has both high-frequency directional noise reduction, low-frequency signal retention, and excellent mechanical properties, and can be widely applied in the fields of transportation, industry, and construction, filling the technical gap of existing sound-absorbing materials in frequency selection characteristics and practicality.

The present disclosure provides a signal generation method, device and communication system, relating to the technical field of wireless communication and terminal. The method comprises: generating a first binary keying signal OOK waveform based on a low-power wake-up LP-WUS signal, replacing part of the waveform of each period in the first OOK waveform with a constant modulus sequence to obtain a target waveform, the constant modulus sequence being a group of sequences with the same modulus but different phases. According to the embodiment of the present disclosure, the first OOK waveform generated based on the LP-WUS signal can be scattered, the frequency diversity gain of the LP-WUS signal is improved, a similar spread spectrum effect is formed, so that the signal can still have good performance when passing through a frequency selective fading channel (such as TDL-C), so as to improve the detection accuracy and detection efficiency of the LP-WUS signal, and further improve the synchronization of NR reception and reduce energy loss.