34results about How to "Narrow frequency band" patented technology

A micromachined design and method with inherent disturbance-rejection capabilities is based on increasing the degrees-of-freedom (DOF) of the oscillatory system by the use of two independently oscillating proof masses. Utilizing dynamical amplification in the 4-degrees-of-freedom system, inherent disturbance rejection is achieved, providing reduced sensitivity to structural and thermal parameter fluctuations and damping changes over the operating time of the device. In the proposed system, the first mass is forced to oscillate in the drive direction, and the response of the second mass in the orthogonal direction is sensed. The response has two resonant peaks and a flat region between peaks. Operation is in the flat region, where the gain is insensitive to frequency fluctuations. An over 15 times increase in the bandwidth of the system is achieved due to the use of the proposed architecture. In addition, the gain in the operation region has low sensitivity to damping changes. Consequently, by utilizing the disturbance-rejection capability of the dynamical system, improved robustness is achieved, which can relax tight fabrication tolerances and packaging requirements and thus result in reducing production cost of micromachined methods.

A multi-beam, polarization diversity, narrow-band cognitive antenna system is disclosed. The antenna system includes a plurality of antenna elements, switching elements, and transmission feed lines disposed on a PCB substrate, inside or on the enclosure of a consumer wireless device, on the airframe of an air vehicle, or on the surface of a ground vehicle. The plurality of switching elements are arranged with the antenna elements and transmission feed lines to, when selectively closed, electrically couple selected ones of the antenna elements and transmission feed lines to one another to generate an antenna configuration selected from a plurality of antenna configurations. A non-volatile memory is configured to store data representing at least some of the plurality of antenna configurations. A control arrangement operatively coupled to the plurality of switching elements and configured to close selected ones of the switching elements as a function of the data stored in said memory. Means are provided to selectively update the data on a function of previously selected antenna configurations.

A method for accurately determining internal failures, such as separations, of a tire without affecting tire behaviors. Radial acceleration signals of a tire during vehicular travel are detected by an acceleration sensor (11) attached to the inner surface of the tire at the axial center of the tread. A frequency analysis is performed on the radial acceleration signals to obtain a frequency spectrum. A band value X_ab is calculated of a specific frequency band [f_a, f_b] within the range of 100 Hz-400 Hz, which includes the frequency of the second lowest peak of the peaks appearing in the frequency spectrum. Then a check is made to see whether or not the difference between this band value X_ab and a predetermined band value Y_ab of a normal tire exceeds a threshold value K. And when Y_ab−X_ab>K, it is determined that an internal failure, such as a separation, is present in the tire.

A method for nondestructive inspection of ceramic structures present as either a ceramic matrix composite structure or a ceramic based coating. Such non-metallic structures are used to provide thermal protection or weight reduction or both to aircraft and their components. The nonmetallic structure is scanned with an electromagnetic pulse in the range of 200 GHz to 4 THz. The electromagnetic pulse includes a plurality of frequencies within the Terahertz range and is not restricted to a single designated frequency. The frequency range is sensitive to changes in impedances and refractive index within the structure. After the electromagnetic pulse passes through the nonmetallic structure, it may be evaluated for changes in impedance in the nonmetallic structure at different locations, and, when present, whether the changes in impedance impact the ability of the structure to perform the function for which it was designed.

The invention discloses a far-infrared environment-friendly coating. The far-infrared environment-friendly coating is characterized by comprising the following substances in parts by weight: 1-5 parts of clay, 2-6 parts of mineral thermal insulation materials, 25-30 parts of fire retardants, 1.5-2.5 parts of defoaming agents, 0.5-2.5 parts of fungicides, 30-40 parts of silicone modified epoxy resin, 10-16 parts of mixed solvents, 4-10 parts of dispersants, 1-6 parts of polyolefin plastic, 2-9 parts of tourmaline crystal mine micro-powder and 3-9 parts of inorganic fillers. According to the far-infrared environment-friendly coating, by utilizing a nanometer technique, the crystal lattice of a prepared far-infrared radiation material is greatly changed, the frequency band is narrow, the pertinence is strong, the radiation rate is high, the toughness of an element is greatly improved, the heat shock stability is good, and the far-infrared environment-friendly coating further has a very wide application prospect in a normal temperature state.

The invention discloses a colloidal crystal-modified optical fiber-capillary microstructural device, which is manufactured by the following main steps of: removing a coating from the common standard monomode optical fiber, inserting the optical fiber into a capillary, fixing the optical fiber by using glue, and polishing a capillary-optical fiber end face; preparing colloidal microsphere solution from different materials such as polystyrene (PS), polymethyl methacrylate (PMMA) and silica; growing a colloidal crystal on the capillary-optical fiber end face by a vertical deposition method, sintering by using a sintering furnace and curing to form a colloidal crystal capillary-optical fiber microstructure; and packaging and fixing by using a thermoplastic sleeve and a plastic box. The formed colloidal crystal-modified capillary-optical fiber microstructure can have a porous structure and can be manufactured into an optical fiber filter and a biological environmental sensor through further development; and the common optical fiber is utilized, so the device is easy and convenient to manufacture and low in cost.

The invention discloses electrostatic induction measurement method and device for local particle velocity in a fluidized bed. The method comprises the following steps of: packing an insulating and isolating material on one end of a metal shield pipe to form an insulating and isolating block, uniformly arranging a plurality of electrodes in parallel in the insulating and isolating block on the same plane to form a first electrostatic induction electrode array and a second electrostatic induction electrode array, and respectively connecting all electrodes in the two electrode arrays by using conducting wires; producing two groups of electrostatic signals reflecting gas-solid flowing information when electrified particles pass through the two electrostatic induction electrode arrays; and amplifying the electrostatic signals by a front-end charge differential circuit, sending to a computer through a data acquisition card, analyzing the spectrum of the differential electrostatic signals in the computer, and determining the peak frequency on the spectrum so as to further acquire the local particle velocity of a gas-solid two-phase flow. The electrostatic induction measurement device for local particle velocity in the fluidized bed comprises a measurement probe, a front-end charge differential amplifying circuit, the data acquisition card and the computer.

A nano-class far infrared radiation material for saving oil of engine aging wine, and disinfecting drinking water is prepared through adding the micron-class powder of Fe2O3, NiO and TiO2 to nano-class mixture powder, ball grinding for at least 72 hrs, shaping and calcine. The said nano-class mixture powder contains zirconium silicate, clay, talc, nickel oxide, cobalt oxide, ferrous oxide, titanium oxide, zinc oxide and MnO2.

A recordable optical information medium includes a recording area including a guide groove on which a recording material layer is provided for forming at least one recording mark which represents first information modulated by a first modulation system; and a pit area including at least one concave and convex type pit which represents second information modulated by a second modulation system. The guide groove and the at least one pit have substantially the same depth. The first modulation system and the second modulation system are different from each other.

A communication method for a radio LAN system provides communication at a first transmission rate. In the method, a first signal of the first transmission rate is time-divisionally distributed into n−1 second signals (n=3, 4, . . . ). The n−1 second signals are respectively converted into n−1 third signals of a second transmission rate less than the first transmission rate. The n−1 third signals of the second transmission rate are also transmitted through radio transmission paths between n−1 radio base stations and a terminal station connected to at least one terminal unit.

The present invention relates to a method and an apparatus for suppressing passive wireless earphones through a pulsed magnet field. According to the method, a continuous pulse wave with the pulse duty factor of 50%:50% and a continuous pulse wave with the pulse duty factor changing within the range from 75%:25% to 25%:75% are adopted, a magnetic field coil is directly driven by superposition of base wave pulses and high-order harmonic pulses, an auditory discrimination mode of human is simulated, and reception of passive wireless earphones is suppressed, so as to interfere and destroy information transmission paths and conditions of cheating-used earphones. Various interference pulse signals are generated by a single chip microcomputer, and power complementary pair transistors are directly driven, the technology and the method are mature, reliable and easy to operate, and audio language classrooms or laboratory site facilities can be directly utilized.

The invention discloses an environmental protection biomaterial, which comprises the following substances by weight: 10-16 parts of clay, 21-26 parts of urea-formaldehyde resin, 16-20 parts of polytetrafluoroethylene gum, 14-16 parts of tartrate, 9-13 parts of methyl benzoate, 10-13 parts of polyvinyl alcohol, 3-6 parts of talcum powder, 1-3 parts of murraya paniculata wood chip, 2-6 parts of Ixora Chinensis wood chip, 9-12 parts of geranium wood chip, 2-6 parts of methyl phenyl siloxane branched prepolymer, 3-6 parts of oilseed straw powder, 12-14 parts of turnip straw powder, 1-6 parts of hollow glass bead and 2-3 parts of graphite powder. The environmental protection biomaterial employs a nano technology, the crystal lattice of prepared Far-IR radiation material has large change, and has the advantages of narrow frequency band, strong pertinency, high radiant ratio, greatly increased element toughness, and good thermal shock stability; and has wide application prospect under normal temperature state.

The invention discloses a weak signal detection device with strong anti-interference performance, the weak signal detection device comprises a filter circuit, a pre-amplification circuit, a lock-in amplifier, a multi-channel amplification circuit, a multi-channel AD acquisition circuit, a DSP, a CAN box and an upper computer which are electrically connected together in sequence, the filter circuitreceives signals, and the lock-in amplifier comprises a modulation module. The device disclosed by the invention is used for a direct current signal or a slow change signal with smaller amplitude; inorder to prevent adverse effects of 1/f noise and direct current drifting (such as temperature drifting of input offset voltage of an operational amplifier) of direct current amplification, a modulator or a chopper is generally used for converting the direct current drifting into an alternating current signal, then the alternating current signal is amplified and processed, and then demodulation and low-pass filtering are carried out to obtain an amplified detected signal. The weak signal detection device designed based on the lock-in amplifier shows excellent performance in the aspect of weaksignal detection.

The invention discloses an NAVTEX message modulation method based on an FPGA, and relates the field of navigation radio communication and software radio. According to the method, the design of an NAVTEX modulator is achieved by using the FPGA according to the properties of an NAVTEX message, as shown in Fig.1, firstly, received effective data are stored in real time by using the ping-pong cache technology so as to accomplish the seamless buffering and processing of the data; then, the NAVTEX message is encoded by using the 4B3Y error detecting code encoding mode, thereby greatly improving the correctness and reliability of digital information transmission; the NAVTEX message is modulated by using an F1B modulation mode, thereby greatly improving the occupancy rate of the frequency band and enhancing the anti-jamming property of the transmission; and finally the modulated message is sent to a transmitter by using a data sending module to accomplish the sending. According to the NAVTEX message modulation method disclosed by the invention, the NAVTEX message modulation is achieved based on the FPGA, various functional modules of the FPGA are completely compiled by using the VHDL language, therefore few resources are occupied, the modularized design and use are convenient, the performance is more stable and reliable, and thus the NAVTEX message modulation method is very suitable for maritime radio communication.