190 results about "High attenuation" patented technology

A dielectric filter includes resonator electrodes, an inter-stage coupling capacitor electrode, and an input / output coupling capacitor electrode on dielectric substrates, respectively. The resonator electrodes are electro-magnetically coupled to each other to form a tri-plate structure, are made of a metallic foil embedded in a resonator dielectric substrate. Another dielectric filter includes an upper shield electrode dielectric substrate, an inter-stage coupling capacitor dielectric substrate, a resonator dielectric substrate, and an input / output coupling capacitor dielectric substrate which are made of a composite dielectric material including a high-dielectric-constant material and a low-dielectric-constant material. The above described arrangement provides the dielectric filter with an improved Q factor of a resonator, a low loss, and a high attenuation.

It has been difficult to provide a band elimination filter having characteristics of a high attenuation within a desired stop band and a low loss over wide frequency bands higher and lower than the stop band. A band elimination filter includes: a plurality of acoustic wave resonators as an acoustic resonator each having one end grounded; and a transmission line to which the other end of each of the plurality of acoustic wave resonators as an acoustic resonator is connected, in which at least some of the other ends are coupled to the transmission line at predetermined intervals, and at least one inductor is provided on transmission line in all or some of the predetermined intervals.

A mechanical vibration sensor adapted to be brought into contact with an object for sensing mechanical vibrations in the object, includes a body of a soft elastomeric material having high transmissivity and low attenuation properties with respect to a preselected type of energy waves; and a pair of transducers mounted, by mounting members having high attenuation properties with respect to the energy waves, in spaced relationship to each other to define a transmission channel between the transducers. Such sensor is particularly useful in a method and apparatus for controlling snoring by a person, by utilizing a stimulus device effective, when sensing snoring, to immediately produce a response in the person tending to interrupt the person's snoring.

A feedforward equalizer for DFE based detector is provided comprising a digital to analog converter to convert an analog signal to a digital signal. A feedforward equalizer comprises a high-pass filter and is responsive to the input circuit. The high-pass filter has a low cutoff frequency, has a relatively flat response and has high attenuation at low frequencies. A decision feedback equalizer comprises a decision circuit responsive to the feedforward equalizer, and a feedback filter is responsive to the decision circuit. The decision circuit is also responsive to the feedback filter.

An antenna duplexer includes first and second filters connected to an antenna terminal. The first filter has a passband of a low frequency band. The second filter has a passband of a high frequency band. The second filter is a ladder-type filter including series-arm resonators and parallel-arm resonators. At least one parallel-arm resonator out of the parallel-arm resonators has a main resonance and an auxiliary resonance. Attenuation poles caused by the main resonance and the auxiliary resonance are within the low frequency band. This antenna duplexer has a high attenuation characteristic and a high isolation characteristic while maintaining a low insertion loss.

A mechanical vibration sensor adapted to be brought into contact with an object for sensing mechanical vibrations in the object, includes a body of a soft elastomeric material having high transmissivity and low attenuation properties with respect to a preselected type of energy waves; and a pair of transducers mounted, by mounting members having high attenuation properties with respect to the energy waves, in spaced relationship to each other to define a transmission channel between the transducers. Such sensor is particularly useful in a method and apparatus for controlling snoring by a person, by utilizing a stimulus device effective, when sensing snoring, to immediately produce a response in the person tending to interrupt the person's snoring.

The invention discloses transmitter and receiver of communication system and synchronization method thereof. The invention aims at the characteristics of periodically changed strong noise, high attenuation, signal distortion and the like of low-voltage network channels, the transmitter transmits modulated data in time in noncontiguous manner to avoid periodically worsened time zones of the channels; a single capture and verify strategy adopted by the receiver detects and identifies effective data intervals to establish accurate synchronous capture. The harmful effects onto communication caused by the severe environment of the channels can be overcome when the invention is adopted in low-voltage power line carrier communication systems, thereby enabling the reliability of the communicationsystems to be improved.

An antenna switch module includes a filter which reduces transmission loss so as to achieve high attenuation in a wide band at harmonic frequencies. This antenna switch module includes the filter, an antenna switch circuit and an adjustment line. The filter passes fundamental frequencies and has an attenuation pole. The antenna switch circuit switches antennas. The adjustment line is connected between the filter and the antenna switch circuit. The adjustment line adjusts its length, and when the filter and the antenna switch circuit are directly connected with each other at a connection point, prevents the impedance when the filter is seen from the connection point and the impedance when the antenna switch circuit is seen from the connection point from becoming complex conjugates of each other at the harmonic frequencies.

A surface-acoustic-wave filter couples a two-port surface-acoustic-wave resonator filter circuit coupled in parallel or in series with a two-port impedance circuit. The two-port impedance circuit has an impedance that creates a pole of attenuation, by making the open-circuit impedance of the surface-acoustic-wave filter equal to the short-circuit impedance. High attenuation over a wide range of stopband frequencies is obtained in this way, combined with steep roll-off between the passband and stopband.

A planar waveguide Mach-Zehnder interferometer (MZ) has improved performance as a variable optical attenuator as well as a thermo-optic switch (TOS) with reduced polarization dependent loss (PDL) in high attenuation states. The PDL was reduced by correcting for the increased birefringence that occurs on heating one waveguide arm by making the two waveguides inherently asymmetric, such that when one of the waveguides is heated, the differential birefringence of the two arms becomes zero. This asymmetry can be realized simply by changing the width of one of the waveguides. The modified device allows for very small PDL in the high attenuation state of a VOA and for theoretically perfect contrast in a TOS in the off state, with only a small penalty in PDL of the on state.

A Full-Duplex Pre-equalized OFDM system for high speed telemetry down-hole wire-line communication. The system compensates for the narrow bandwidth, high attenuation of, and noise in a downhole wireline using Trellis Code Modulation and Reed Solomon encoding.

The invention discloses a microwave millimeter wave ultra-wide band low phase shift six-figure attenuator formed by cascading a 0.5dB attenuation unit, a 1dB attenuation unit, a 2dB attenuation unit, a 4dB attenuation unit, a 8dB attenuation unit and a 16dB attenuation unit, wherein the 0.5dB attenuation unit and the 1dB attenuation units are in T-shaped topological structures; the 2dB attenuation unit and the 4dB attenuation units are in an n-shaped topological structures; the 8dB attenuation unit is in a structured formed by cascading two n-shaped topological structures; the 16dB attenuation unit is in a switched topological structure; the 2dB attenuation unit, the 0.5dB attenuation unit, the 16dB attenuation unit, the 1dB attenuation unit, the 8dB attenuation unit and the 4 dB attenuation unit are in cascade connection in sequence; the work frequency range of the attenuator is 2-18GHz; and 64 attenuation states can be realized within the attenuation range of 0.5-31.5dB by taking 0.5dB as a stepping value. The attenuator has the advantages of simple circuit topological structure, simpleness and convenience for design, low process difficulty, low inserting loss, small phase shift and high attenuation precision for various attenuation states, small standing wave ratio of the input end voltage to the output end voltage, wide working band, small circuit size, simpleness for control and convenience for use and is convenient for large-batch production by adopting a microwave singlechip integrated circuit process technology.

An apparatus and a method for correcting a CT slice image for an image artifact (330) caused by the motion of a high attenuation part (140) in an object (135) of interest. The CT slice image is based on projection images (310a,b). The apparatus and method uses a footprint (315a,b) of the part in each of the projection images (310a,b).

A multicarrier data transmission scheme is provided. According to the provided scheme, a radio transmitter encodes data bits with different degrees, the degree of an encoded data bit being defined by the number of parity check equations protecting the data bit. The data bits are preferably encoded with an irregular low-density parity check (LDPC) code. The encoded data bits are then mapped to symbols. The symbols are allocated to subcarriers of a multicarrier radio signal on the basis of channel state information obtained from the radio receiver and the degree used with respect to each symbol. On the basis of the channel state information, a number of subcarriers are truncated due to high attenuation, and the number of subcarriers to be truncated relative to the total number of subcarriers is substantially fixed. The available transmit power to the non-truncated subcarriers. The multicarrier signal comprising symbols on the non-truncated subcarriers is then transmitted to the radio receiver.

Selectable attenuators are used in the reference and test paths of a VNA, with attenuation automatically inserted or deleted when the Device Under Test (DUT) attenuation reaches predetermined thresholds. Attenuation in the reference channel is removed when the signal in the test channel is sufficient to overcome the leakage of the reference channel. Additionally, attenuation is removed from the test channel when the reference channel has a high attenuation inserted to further increase the difference between the leakage reference signal and the reduced test channel signal thus allowing lower isolation requirements on the two (or more) receiving channels.

The invention provides an ultra-wide-band filter with high selectivity and an ultrahigh attenuation band restrain effect, which is composed of a first input / output port, a second input / output port, an interlayer medium substrate, an upper layer micro-strip structure arranged on the interlayer medium substrate and an underlying metal floor board. The upper layer micro-strip structure comprises a first feed network, a multi branch knot loading multimode resonator and a second feed network. The multi branch knot loading multimode resonator of the upper layer micro-strip structure has five resonance modes in an ultra-wide-band frequency band scope, a transmission zero is generated above and below a passband respectively, and passband selectivity is greatly improved. In addition, generated zero and frequency doubling zero of the zero restrains high sequence resonance modes of the multimode resonator, and restraining effects of an upper attenuation band of the passband are greatly broadened. The ultra-wide-band filter has good passband character, high passband selectivity and ultra-high attenuation band restraining effect, and is applicable to ultra-wide-band wireless communication systems with high standard communication.

A method of at least partially compensating for an x-ray tube target angle heel effect includes positioning a filter having an anode side and a cathode side between an x-ray source and an x-ray detector, wherein the cathode side has a higher attenuation coefficient than the anode side, to at least partially compensate for the target angle heel effect.

The invention is applicable to the technical field of microwave attenuators and provides a microwave program-control step attenuator, which comprises a microwave signal input end, a microwave signal output end, microwave transmission channels, channel switching units and microwave attenuation units. The microwave signal input end is connected with the channel switching units through the microwave transmission channels. The channel switching units are connected with the microwave attenuation units through the microwave transmission channels. The microwave attenuation units are connected with the microwave signal output end through the microwave transmission channels. The microwave program-control step attenuator provided by the invention is different from an optical attenuator, uses MEMS (Micro Electro Mechanical System) switches as the channel switching units of a microwave transmission line and enables microwaves to be switched between straight-through transmission lines and broadband attenuating sheets, so that the goals of attenuation amount program control and step attenuation are realized. By using distributed resistive attenuating sheets as the microwave attenuation units, the microwave attenuation units are enabled to have very high attenuation accuracy within a wider frequency range.

The invention discloses a method and a measuring device thereof for measuring the granularity distribution of the particle in the discrete state, and the method and the measuring device thereof to the technical field of ultrasonic measurement. The invention aims at solving the technical problem of non contact measurement of the distribution of the particle granularity in the discrete state. The measuring device includes a computer which applies a complex wave number, a objective function, a distillation function and other calculation formulas to optimize the calculate the distribution of the particle granularity, a signal process circuit which is connected with the computer, a pulse wave launch / receive circuit which is connected with the signal process circuit, a broadband transducer which is connected with the pulse wave launch / receive circuit, and broadband transducer is arranged at the external side of a test plate. The measuring device is controlled by the computer, and the launch circuit sends out a pulse signal; a trigger transducer sends out the sound wave which is reflected by the wall of the test plate for a plurality of times and then is received by the transducer, and then the signal process circuit amplifies the signal, the high speed module coverts the signal and sends to the computer for processing. The invention is characterized in that the invention can completely realize the non contact measurement, and measure the high consistency and the two-phase flow of the high attenuation particle on line.

A personal electromagnetic security unit for shielding portable electronic communication and data devices such as cell phones and computers. The shielding unit includes a coated liner construction in which a high-attenuation metallized fabric is coated with a second attenuating material to enhance the electromagnetic absorption or reflection characteristics of the unit. This two-part conductive layer forms the inner liner of the shielding unit, with the coated side being protected by the unit's exterior material and preferably an intervening layer of padding.

The invention discloses a grapheme based electronically controlled terahertz attenuation piece, a preparation method and a utilization method. The attenuation piece comprises a substrate; at least two layers of grapheme layers are paved on the substrate; a layer of medium layer is paved between every two adjacent layers of grapheme layers; the mediums layers separate the two layers of grapheme layers. According to the grapheme based electronically controlled terahertz attenuation piece, the regulation range of device attenuation degrees can be changed through different layers of the grapheme, a high attenuation degree is achieved theatrically, the attenuation degree parameters can be controlled due to control of the attenuation degree of the attenuation piece through voltage, and the application accuracy of the attenuation piece products is high and flexible.

An apparatus and method of processing X-ray projection data including spectral computed tomography (CT) projection data. The spectral CT data is decomposed into material projection lengths using a material-decomposition method that includes an initial-estimate method to provide an initial projection-lengths estimate. The initial-estimate method can include first reconstructing an image using non-spectral CT data, and then subdividing the reconstructed image into materials according to the relative attenuation density of areas within the reconstructed image (e.g., high attenuation areas correspond to a high attenuation material such as bone). The projection length estimates of each material are then obtained by forward projecting the corresponding subdivision of the reconstructed image. Also, the initial estimate can be obtained / refined by selecting the projection lengths with smallest cost-function value from randomly chosen projection lengths within a sample space. The initial estimate can also be conditioned on the X-ray flux at the X-ray source.

The invention relates to an underwater light field sampling and simulating method which designs an underwater light field sampling device and realizes the simulation of an underwater light field based on sampled data. The method comprises the following steps: (1) designing an underwater panoramic illumination sampling device; (2) enabling the sampling device designed in step (1) to descend from the water surface to a set depth at a constant speed, and simultaneously acquiring a group of equally-spaced underwater sampled data changing with the depth; (3) after sampling underwater illumination images in step (2), respectively carrying out a noise smoothing treatment on each group of illumination images, and splicing the illumination images sampled by two fisheye cameras at the same depth into a whole panoramic illumination image; and (4) after obtaining a group of panoramic illumination images at different depths in step (3), calculating the panoramic illumination image at the depth in which a scene stays, adding scene model data, and carrying out underwater illumination rendering by a ray tracing algorithm. Based on the characteristics of high attenuation degree of visible light in the underwater environment and complex interference in water, according to the method in the invention, the underwater illumination model is established; and the method has the advantages of strong sense of reality and easy implementation.

A method for deep paging in a communication system employing orthogonal channelizing codes, such as Walsh sequences, of predetermined length m, that does not require a high powered paging channel. The method includes the steps of generating a paging channel message which is combined with a Walsh sequence having a length greater than or equal to 2m, and transmitting the paging channel message at a data rate of less than 4800 bits per second (bps). By transmitting the paging channel message at a low data rate and integrating collected energy over a period longer by a factor on the order of 1000, the message is able to penetrate buildings and other structures or high attenuation environments, thereby allowing one to successfully page a user terminal that is inside such a structure or area. Preferably, the paging channel message is formed using an auxiliary Walsh sequence on the order of 65536 chips in length, and the data rate is less than 10 bps.

The invention relates to an ultra-narrow bandwidth dual-band filter based on an asymmetric step impedance resonator. The ultra-narrow bandwidth dual-band filter comprises a medium substrate, a micro-strip line on the upper surface of the medium substrate and a grounding metal coating on the lower surface of the medium substrate. The micro-strip line on the upper surface of the medium substrate consists of two identical asymmetric step impedance resonators A and B, an input feed line and an output feed line. The resonator A is folded with the resonator B into a spiral shape, the resonators A and B are mutually coupled with each other in a weak manner, and the input and output feed lines are respectively coupled with the resonators A and B to feed. The dual-band filter in the embodiment has a small size and good frequency selectivity, low insertion loss inside a pass-band and high attenuation outside the pass-band can be realized, and the ultra-narrow bandwidth dual-band filter can be used for the design of a ultra-narrow bandwidth miniaturized dual-band filter in a wireless communication system.

The present invention relates to a method for measuring particle size distribution of discrete state particles based on a continuous wave and a burst wave. According to the method, a computer edits a continuous wave and a burst wave; waveform signals are output; an excitation electrical signal is emitted through a signal generator; power amplification and circuit amplification are performed; an excitation transducer emits ultrasonic waves; the ultrasonic waves pass through a sample requiring measurement in a measurement zone, and are captured by a receiving transducer on the opposite side; the captured ultrasonic waves are subjected to signal amplification and analog-to-digital conversion, and transmitted to a computer to be processed, wherein the signal amplification is performed by a signal processing circuit, and the analog-to-digital conversion is performed by a high speed analog-to-digital conversion circuit; a penetrating beam path change method is adopted to measure an acoustic attenuation signal, an acoustic attenuation coefficient of the particle sample is calculated, and particle size distribution and concentration of the high concentration and high attenuation particles are calculated based on the acoustic attenuation spectrum, wherein the measurement signal is clear. With the present invention, rapid measurement of particle size distribution of discrete state particles is achieved.

A power converter includes an output filter circuit including first and second inductive elements; a voltage source coupled to the output filter circuit, the voltage source for generating a voltage across the output filter circuit, the voltage including an alternating voltage component, the alternating voltage component causing the application of an alternating current to the first inductive element of the output filter circuit; and an attenuation filtering circuit. The attenuation filtering circuit includes a first magnetically coupled inductive arrangement for generating a first opposing alternating current in response to the alternating voltage applied to the first inductive element of the output filter circuit; a first combining element for combining the first opposing alternating current with the alternating current to partially cancel the alternating current, thereby producing an attenuated alternating current applied to the second inductive element of the output filter circuit; a second magnetically coupled inductive arrangement for generating a second opposing alternating current in response to the attenuated alternating current applied to the second inductive element of the output filter circuit; and a second combining element for combining the second opposing alternating current with the attenuated alternating current to substantially cancel the attenuated alternating current.

A multicarrier data transmission scheme is provided. According to the provided scheme, a radio transmitter encodes data bits with different degrees, the degree of an encoded data bit being defined by the number of parity check equations protecting the data bit. The data bits are preferably encoded with an irregular low-density parity check (LDPC) code. The encoded data bits are then mapped to symbols. The symbols are allocated to subcarriers of a multicarrier radio signal on the basis of channel state information obtained from the radio receiver and the degree used with respect to each symbol. On the basis of the channel state information, a number of subcarriers are truncated due to high attenuation, and the number of subcarriers to be truncated relative to the total number of subcarriers is substantially fixed. The available transmit power to the non-truncated subcarriers. The multicarrier signal comprising symbols on the non-truncated subcarriers is then transmitted to the radio receiver.