257 results about "Null point" patented technology

A circuit for a nuclear magnetic resonance probe uses three resonators to create resonances intermediate to the resonator resonant frequencies. The circuit is particularly useful for creating magnetic fields for two closely spaced high frequencies, such as those used for the excitation of 1H and 19F. The resonators are arranged in a parallel combination, or the electrical equivalent thereof, with input ports connected to it for inputting the desired high frequency resonances. Admittance inverters may be used to provide isolation between the input ports. Some of the resonators and the admittance inverters may be transmission lines. The transmission lines may have additional ports for additional input signals of lower frequencies located at null points for the frequencies of the signals coupled to the primary input ports. Adjustable dielectric components in the resonator transmission lines may be used for tuning purposes.

A wireless control apparatus is disclosed that forms and controls an area of a base station according to an antenna pattern. The wireless control apparatus includes an area formation information gathering part that gathers area formation information pertaining to area formation of a neighboring base station; and an antenna pattern control part that controls and directs at least one of a main lobe, a side lobe, and a null point between the main lobe and the side lobe of the antenna pattern based on the area formation information to reduce frequency interference between a current cell formed by a current base station and a neighboring cell formed by the neighboring base station.

A target object information estimating device embodied by an electronically agile radar sensor is mounted in a moving vehicle. The device has a unit outputting a radar wave every measuring period, receiving radar waves reflected from a target object through different transmission paths and calculating a distance to the object in each measuring period to detect the object, a unit tracking the object in a tracking term of measuring periods, a unit setting the distance changed with time as a null distance each time electric power of the received waves is reduced to a minimal value, and a unit producing an actual pattern of null points corresponding to the null distances, collating the actual pattern with modeled patterns corresponding to various heights and estimates the height of the object from the collation result as information about the object.

A lane recognizing image processing system for recognizing lane markings laid on a driving road for motor vehicles includes a lane marking candidate point extraction means (20) for extracting lane marking candidate points (C) from an image (G) taken by an image pickup means (10) mounted on the motor vehicle, and a lane recognizing means (30) for recognizing a lane defined on the road on the basis of set of the lane marking candidate points (C). The lane recognizing means (30) includes a lane marking candidate point position converting means (31) for recognizing as lane marking candidate point positions the positions of the lane marking candidate points (C) transformed onto a straight line extending toward a null point.

A radio base station (BS2) comprises: a transmitter (1412) that transmits, via a plurality of transmission antennas, a radio signal to a first radio terminal having a plurality of reception antennas; a transmission directivity controller (1422) that controls directional beam, which is formed by the transmission antennas, on the basis of feedback information that is fed back from the first radio terminal; and an information acquiring unit (1421) that acquires control information to be used for directing the null points of the directional beam toward a second radio terminal that receives, as an interference signal, the foregoing radio signal during communication with another radio base station. The transmission directivity controller (1422) directs, based on the feedback information and control information, the directional beam toward the first radio terminal and the foregoing null points toward the second radio terminal.

An array antenna apparatus includes a transmission-array-antenna including transmission-antenna-elements, a transmission-side directivity control unit controlling a directivity of the transmission-array-antenna by controlling phases of at least part of the transmission-antenna-elements, a reception-array-antenna including reception-antenna-elements, and a reception-side directivity control unit controlling a directivity of the reception-array-antenna by controlling phases of the reception-antenna-elements. The array antenna apparatus has a composite transmission / reception directivity, in which the direction of a grating lobe of one of the transmission-array-antenna and the reception-array-antenna agrees with the direction of a null point or part of side lobes of the other of the transmission-array-antenna and the reception-array-antenna, and the direction of a grating lobe of the other of the transmission-array-antenna and the reception-array-antenna agrees with the direction of a null point or part of side lobes of the one of the transmission-array-antenna and the reception-array-antenna, and scans in a scanning range with the composite transmission / reception directivity.

A radiator element includes a pair of substrates each having a transition section and a feed surface, each of the substrates is spaced apart from one another. The radiator element further includes a balanced symmetrical feed having a pair of radio frequency (RF) feed lines disposed adjacent to and electromagnetically coupled to the feed surface of one of a corresponding one of the pair of transition sections, and the pair of radio frequency feed lines forms a signal null point adjacent the transition sections.

The invention relates to a device and a method for on-line three-dimensional measuring of a laser radar of heavy forging in the measuring technical field, which comprises a two- dimensional laser radar, a servo-motor, a junction box, a rotary main shaft, a spacing and null point sensor, a bearing block which is provided with a bearing, a band brake apparatus, a back supporting stand of the laser radar, an L-shaped mounting bottom plate, a vertical mounting chassis, a movement-control card, a data collecting card, and a computer which is used for processing data. Firstly, the laser radar is positioned on the horizontal surface of a forging axial cord, then four surfaces of the forging are respectively scanned by the laser radar, the two-dimensional laser scanning radar is scanned in the surface which is vertical to an axial cord of the forging, the servo-motor drives the laser radar to rotate in the horizontal surface, thereby the three-dimensional scan of the forging is realized, finally, shape and parameter of the forging are gained through data process, and deviation of the shape of the forging is gained. The invention greatly increases accuracy and speed of identification, enlarges range of application, satisfies measuring requirement of a forging, and effectively increases measuring accuracy and efficiency of the forging.

Feedback loops are used within a Multiport Amplifier (MPA) of a communications satellite to maintain phase and amplitude tracking and hence isolation and combining performance. at Ku and Ka-bands, for which there is increasing interest in MPA applications, and where wavelengths are short and maintenance of phase / amplitude tracking becomes highly challenging. Feedback loops are located at strategic points within the MPA Output Network (ONET) to detect tracking errors and provide compensation. Errors are detected through power measurements at “null points”, with zero power corresponding to accurate tracking. The feedback loops adjust the MPA phase / gains such that the levels at these points are maintained at zero. The scheme operates with a pilot signal for measurement of nulls, injected at one of the MPA inputs.

DQPSK modulator control is provided using a single monitor photodiode with a selectively injected dither tone. The dither tone signal is sequentially injected into arm modulators and / or to a modulator driver port in time slots. A tapped signal at the output of the modulator is monitored synchronously with injected dither (I arm, Q arm, or phase modulator in third slot). The recovered dither output from a single photodiode is processed in the same sequence as the dither injection to adjust the bias to the optimal point: I-arm at the null point, Q-arm at the null point, and phase modulator at the quadrature point. This technique can be used for any control where the rate of change of the monitored condition due to systemic or environmental conditions (e.g., temperature, aging, etc.) is slow enough to allow time slot dither injection, monitor, and control.

The invention provides a measuring method for frequencies of low-frequency signals. The method is characterized by comprising the following steps: sampling for tested electric signals; selecting a plurality of sampling points around the signal null point to fit a straight line which intersects with the time axis at the ZCP (zero crossing point) according to sampling values. The cycles or the frequencies of the tested signals can be calculated according to the ZCP. The method of the invention does not require the transformation of low-frequency signals into square waves, and is particularly suitable for the frequency measurement of low-frequency sinusoidal signals. The measuring system is easy to be tested and the cost of the equipment is low. The measuring system also boosts a good anti-interference capability and easy operation. The data obtained by this method is precise and reliable.

A transmitter includes an antenna array having a plurality of antennas for a wireless communication with one or more receivers, and a precoder connected to the antenna array, the precoder to apply a set of beamforming weights to the antenna array, the set of beamforming weights selected from a codebook to form by the antenna array one or more transmit / receive beams or nulls pointing in selected directions. The codebook includes a plurality of sets of beamforming weights for a plurality of directions. The beamforming weights in the codebook are based on a first antenna array response matrix, the first antenna array response matrix defined by a second antenna array response matrix and one or more characteristic matrices. The first antenna array response matrix contains first array response vectors of the antenna array, the second antenna array response matrix contains second array response vectors of another antenna array, the other antenna array being different from the antenna array, and the one or more characteristic matrices describing characteristics of the antenna array.

A flexible manipulator control method based on the non-linear active disturbance rejection control technique includes the steps of building a flexible manipulator system module, initializing the system state and controller parameters, designing a high-order tracking differentiator, designing a non-linear extended state observer, determining the observer parameters through a pole assignment mode and adding non-linear feedback. The extended state observer is designed and used for estimating the system state and external disturbance. The observer gain parameter is determined through the pole assignment mode. A non-linear feedback control law is designed, the effect that the system tracking error is rapid and stable and converges to the null point is guaranteed, and finally rapid and stable control over a flexible manipulator system is realized. By means of the flexible manipulator control method based on the non-linear active disturbance rejection control technique, the problem that the internal state of the system and external disturbance can not be observed is solved, the influences of non-linear links and uncertain items existing in the system are made up, the problem of a common PID control method is relieved, and the system can rapidly and stably track expected signals.

Direct-write lithography apparatus and methods are disclosed in which a transducer image and an image of crossed interference fringe patterns are superimposed on a photoresist layer supported by a substrate. The transducer image has an exposure wavelength and contains bright spots, each corresponding to an activated pixel. The interference image has an inhibition wavelength and contains dark spots where the null points in the crossed interference fringes coincide. The dark spots are aligned with and trim the peripheries of the corresponding bright spot to form sub-resolution photoresist pixels having a size smaller than would be formed in the absence of the dark spots.

The invention discloses a Kalman filtering transformer fault prediction method based on a neural network. The Kalman filtering transformer fault prediction method comprises the following steps that monitoring data of a transformer are obtained; the monitoring data are subjected to segmentation processing according to time periods, and a data set of each time period is obtained; outlier points of the data sets are judged, the number of the outlier points is counted, the outlier points are converted into normal data values, and null points and ultra-range points in the data sets are removed to form new data sets; the new data sets are subjected to regression analysis, a model of performing regression analysis is established, and the monitoring data are predicted to obtain prediction trend results; and a fault diagnosis model is established, the prediction trend results are input to the fault diagnosis model to conduct fault diagnosis, and fault diagnosis prediction results are obtained.Possible future trends of the monitoring data can be predicted. Through establishment of the fault diagnosis model and a neural network model and through model prediction, diagnosis results of possible future faults of a high voltage transformer can be obtained.

The invention discloses an electromechanical servo system friction compensation and variable structure control method based on a neural network. The electromechanical servo system friction compensation and variable structure control method based on the neural network includes steps: building an electromechanical servo system model and a Lugre friction model, and initializing system status and related control parameters; estimating friction force through the neural network, and compensating the friction force into a system. A linear extended state observer is designed and used to estimate non-measurable system status and uncertain items including parameter perturbation and neural network estimation errors. A sliding mode variable structure controller is designed according to the system status and the parameter perturbation which are estimated by the linear extended state observer, and therefore the electromechanical servo system friction compensation and variable structure control method based on the neural network guarantees that system trace errors can rapidly and stably converge to a null point, and achieves rapid and stable control for an electromechanical servo system.

A communication system (e.g., a speakerphone) includes an array of microphones, a speaker, memory and a processor. The processor may be configured to perform acoustic echo cancellation, to track multiple talkers with highly directed beams, to design beams with nulls pointed at noise sources, to generate a 3D model of the physical environment, to compensate for the proximity effect, and to perform dereverberation of a talker's voice signal. The processor may also be configured to use a standard codec in non-standard ways. The processor may perform a virtual broadside scan on the microphone array, analyze the resulting amplitude envelope for acoustic source angles, examine each of the source angles with a directed beam, combine the beam outputs that show the characteristics of intelligence or speech.

Disclosed is a motor servo system bilateral neural network friction compensation and limited time coordination control method. The motor servo system bilateral neural network friction compensation and limited time coordination control method includes: building a motor servo system model, and initializing system states an related control parameters; building a Lugre model of nonlinear friction, and dividing the Lugre model of the nonlinear friction into a static portion and a dynamic portion; using a bilateral neural network to respectively estimate a static portion and a dynamic portion of the nonlinear friction, and designing a weight updating rule; according to a system equation, designing a limited time synergy controller, eliminating a buffeting problem in sliding mode control, and guaranteeing that the system states can rapidly and stably converge to a null point.

A method for generating a magnetic resonance image includes a series of inversion and saturation pulses, in which the pulses null the MRI signal from both fat and a second tissue for a single MRI acquisition. An inversion pulse is used to provide a null point for the second tissue. A pair of fat-selective saturation and inversion pulses are used to null the MRI signal from fat at approximately the same time as the second tissue reaches its null point. The saturation pulse is used to create a known state for the fat magnetization, allowing the flip angle of the fat-selective inversion pulse to be determined such that the null point of fat approximately coincides with the null point of the second tissue.

The present invention provides a system and method for on-the-fly optimization of the timing of suppression pulses and a k-space filling scheme for user-prescribed imaging parameters. The invention also minimizes total data acquisition time for the sequence tailored to the particular user-prescribed imaging parameters. A pulse sequence uses a 180° pulse to invert the magnetization corresponding to the suppressed tissue so that a maximum amount of time is provided to play out alpha or imaging pulses after each inversion. The pulse sequence optimizes the number of alpha pulses played out after each inversion pulse based on a specific protocol or imaging parameters selected by the user. This pulse sequence allows for a modified k-space filling scheme that places, at the center of k-space, the echo that most closely corresponds to the null point of the suppressed tissue. For the first inversion pulse, a flip angle less than 180° is used to drive the suppressed tissue magnetization into a steady-state condition immediately.

The invention discloses a broadband linear equalization circuit which comprises a capacitor resistor negative feedback equalization circuit. The broadband linear equalization circuit is characterized by further comprising a difference active inductor structure. The two input ends of the difference active inductor structure are connected with the two difference output ends of the capacitor resistor negative feedback equalization circuit respectively. The difference active inductor structure provides a null point and a pair of conjugate complex number poles, wherein high-frequency gain peak values can be introduced by the conjugate complex number poles, and the null point can eliminate a main pole point of the capacitor resistor negative feedback equalization circuit. Compared with the prior art, the broadband linear equalization circuit can provide wider band width and larger high-frequency gains, and has advantages on the area and power consumption.

The invention relates to an aircraft attitude measuring method based on magnetic sensor combination. The aircraft attitude measuring method includes the first step of enabling three magnetic sensors to be installed on three coordinate axes of a carrier coordinate system respectively; the second step of obtaining a graph of relation between output shafts on the three magnetic sensors and pitch angles sigma m under the assumption that a yaw angle psi and a roll angle gamma are given; the third step of analyzing the relation of attitude angles of the three output shafts when Msy and Msz obtain a null point and an extreme point, and combining with the graph of relation obtained in the second step to obtain a graph of relation between a pitch angle difference value and the yew angle psi when the Msy and Msz obtain an extreme value; the fourth step of obtaining the pitch angle difference value according to the time when the Msy and Msz reach the extreme value, and comparing the graph of relation, obtained in the third step, between the pitch angle difference value and the yew angle psi to obtain the yew angle psi; the fifth step of obtaining the pitch angles sigma m by combining with the graph of relation obtained in the second step and according to the yew angle psi, and obtaining the roll angle gamma according to the relation of attitude angles obtained in the third step.

An optical modulation device including: bias power supplies that output a signal having a bias voltage corresponding to the null point of an optical modulation unit to the optical modulation unit; and synchronous detection circuits that determine whether an intensity of a QAM signal at a drift non-occurrence time where no drift occurs in the bias voltage becomes larger or smaller than the intensity of the QAM signal at a drift occurrence time where a drift occurs in the bias voltage, adjust the bias voltage to maximize the intensity of the QAM signal when determining that the intensity of the QAM signal at the drift non-occurrence time becomes larger than the intensity of the QAM signal at the drift occurrence time, and adjust the bias voltage to minimize the intensity of the QAM signal when determining that the intensity of the QAM signal at the drift non-occurrence time becomes smaller than the intensity of the QAM signal at the drift occurrence time.

Feedback loops are used within a Multiport Amplifier (MPA) of a communications satellite to maintain phase and amplitude tracking and hence isolation and combining performance. at Ku and Ka-bands, for which there is increasing interest in MPA applications, and where wavelengths are short and maintenance of phase / amplitude tracking becomes highly challenging. Feedback loops are located at strategic points within the MPA Output Network (ONET) to detect tracking errors and provide compensation. Errors are detected through power measurements at “null points”, with zero power corresponding to accurate tracking. The feedback loops adjust the MPA phase / gains such that the levels at these points are maintained at zero. The scheme operates with a pilot signal for measurement of nulls, injected at one of the MPA inputs.

The present invention relates to a linear equalizer applicable to a high-speed serial interface, comprising a differential input pair transistor consisting of a first NMOS transistor M1 and a second NMOS transistor M2, a bias current source consisting of a third NMOS transistor M3 and a fourth NMOS transistor M4, a pair of differential input signals VINP and VINN, and a pair of differential output signals VOUTP and VOUTN. The linear equalizer further comprises a capacitance-resistance negative feedback equalizer circuit consisting of a variable resistor RS and a variable capacitor CS and an active inductor consisting of a resistor RG and a fifth NMOS transistor M5, which form an output load together with two load resistors RL. According to the linear equalizer applicable to a high-speed serial interface, an active inductor can generate a null point higher than channel bandwidth, and provide broader bandwidth and a greater high-frequency gain in a high-speed serial data transmission process, so that equalizer performance is improved, and a chip area of an integrated circuit chip is effectively reduced, thereby reducing power consumption.

The invention relates to an optical frequency shift inhabitation method of an SERF atom magnetometer. In the normal optical frequency shift inhabitation method of an SERF atom magnetometer, the frequency of the pumping light is adjusted to be in the center of a spectral line of an atomic absorption spectrum. However, an alkali metal air chamber of the SERF atom magnetometer is characterized by high atomic density and big buffering gas pressure, so the center of the spectral line is hard to obtain. Therefore, the definition of the normal optical frequency shift inhabitation method is not high. According to the optical frequency shift inhabitation method provided by the invention, under two different pumping light strengths, by combining the three dimensional in-situ magnetic compensation technology, the size of the magnetic field sensed by atoms corresponding to the different pumping light frequencies is measured, and theoretic fitting and resolving on the measured data, so optical frequency shift null points can be precisely found, thereby achieving sufficient inhabitation of the optical frequency shift. The optical frequency shift inhabitation method provided by the invention is independent of measurement of the atomic absorption spectrum, and the optical frequency shift inhabitation level depends on the precision of the magnetic compensation, so compared with the normal method, the optical frequency shift inhabitation method provided by the invention is quite high in inhabitation precision.

A lane recognizing image processing system for recognizing lane markings laid on a driving road for motor vehicles includes a lane marking candidate point extraction means (20) for extracting lane marking candidate points (C) from an image (G) taken by an image pickup means (10) mounted on the motor vehicle, and a lane recognizing means (30) for recognizing a lane defined on the road on the basis of set of the lane marking candidate points (C). The lane recognizing means (30) includes a lane marking candidate point position converting means (31) for recognizing as lane marking candidate point positions the positions of the lane marking candidate points (C) transformed onto a straight line extending toward a null point.

A target object information estimating device embodied by an electronically agile radar sensor is mounted in a moving vehicle. The device has a unit outputting a radar wave every measuring period, receiving radar waves reflected from a target object through different transmission paths and calculating a distance to the object in each measuring period to detect the object, a unit tracking the object in a tracking term of measuring periods, a unit setting the distance changed with time as a null distance each time electric power of the received waves is reduced to a minimal value, and a unit producing an actual pattern of null points corresponding to the null distances, collating the actual pattern with modeled patterns corresponding to various heights and estimates the height of the object from the collation result as information about the object.