205 results about "Maximum phase" patented technology

The ability of an ultrasonic system to sweep and lock onto a resonance frequency of a blade subjected to a heavy load at startup is improved by applying a high drive voltage or a high drive current while systematically increasing the level of the applied signal. Increasing the drive signal to the hand piece results in an improved and more pronounced “impedance spectrum.” That is, under load, the increased drive signal causes the maximum phase margin to become higher and the minimum / maximum impedance magnitude to become more pronounced. Increasing the excitation drive signal to the hand piece / blade at startup significantly alleviates the limiting factors associated with ultrasonic generators, which results in an increase of the maximum load capability at startup.

A three-phase DC motor output stage including a predriver that supplies drive voltages to power MOSFETs supplies output voltages to three-phase coils, monitors whether each of gate-to-source voltages of the power MOSFETs is greater than or equal to a predetermined voltage and thereby detects a current zero cross, and employs the output of such current zero cross detection in PLL control for controlling energization switching timing and thereby forms drive voltages of 180-degree energization. Lower hooks with a voltage minimum phase as GND and upper hooks with a voltage maximum phase as a source are set as patterns alternately repeated for every electrical angle of 60 degrees. The patterns are expressed in linear approximation to generate sine wave-like drive voltages, thereby causing sine wave-like currents to flow into the three-phase coils.

An apparatus for adjusting a sampling phase in analog to digital conversion, and an adjustment method thereof is disclosed. Provided are an apparatus for adjusting a sampling phase of a digital display including a phase locked loop (PLL) circuit unit for converting a frequency of a sampling clock signal and outputting the converted frequency, the sampling clock signal for converting an analog video signal into digital format, an analog to digital converter (ADC) for converting the incoming analog video signal into digital format using the sampling clock signal input from the PLL circuit unit, a detection unit for detecting a maximum phase shift of the video signal converted at the ADC, and a control unit for controlling the PLL circuit unit so that the sampling phase can be adjusted in accordance with the maximum phase shift detected by the detection unit, and an adjustment method of the apparatus.

The invention relates to a three-dimensional gel network carrier and a form-stable phase change composite material which adopt fatty acid (hydrocarbon), polyethylene glycol and other organic phase change materials as work material and use poly-(N-hydroxymethyl)-acrylamide heat-shrinkable interpenetration network as form-stable carrier. The preparation method of the phase change composite material comprises the following steps: firstly adopting low temperature eutectic method to select multiple components composite phase change material with proper phase change temperature, high phase change enthalpy and low cost, designing and determining the preparation method of the interpenetration network carrier and the addition mode of the composite phase change material and the combination mode of the carrier, preparing the form-stable phase change composite material based on multiple actions of bonding, physical adsorption and network confinement, cooling and grinding to obtain the form-stable heat storage functional particles. The form-stable phase change composite material containing 50%-75% of material can be prepared by the method, the maximum phase change enthalpy can be up to 110J / g, and the form-stable phase change composite material prepared by the method can be directly applied in the textile field, building field, military field, etc.

A method and apparatus is disclosed to overcome the effects of intersymbol interference during data transmission. Overcoming the effects of intersymbol interference makes possible higher data transmission rates for a given error rate. In one embodiment a receiver-transmitter pair is configured with a precode filter at the transmit side and a feed forward filter and a feedback filter at the receive side. Filter coefficients are calculated to reduce the undesirable effects of the channel, such as intersymbol interference. In one embodiment a training process occurs with the feedforward filter and a feedback filter, such that the first N coefficients of the feedback filter are set to zero. Thereafter, the coefficients of the feedforward filter are subject to spectral factorization and separated into minimum phase roots and maximum phase roots. The minimum phase roots comprise the precode filter coefficients and the maximum phase roots are established as feedforward filter coefficients.

A method for operating a metal detection system that comprises a balanced coil system. One embodiment of the method comprises: determining the phase and magnitude of related signals at least for a first metal contaminant for at least two transmitter frequencies and for at least two particle sizes of the first metal contaminant; determining the phase and magnitude of the related signal for a specific product for the at least two transmitter frequencies; comparing information established at least for the first metal contaminant and the information established for the product; determining a transmitter frequency with which signal components of smallest sized particles of the at least first metal contaminant differ sufficiently or most in phase and amplitude from the phase and amplitude of the product signal; and selecting the transmitter frequency for measuring the product. A metal detection apparatus adapted to operate according to an exemplary method is also provided.

A PWM inverter with a PWM pulse output. The PWM pulse signal is output upon magnitude comparison of phase voltage commands with a carrier wave of a triangular or a saw-tooth waveform. A maximum phase whose absolute value is a maximum among absolute values of phases of the phase voltage commands is selected. In a case where the phase voltage commands of the maximum phase are larger than a maximum value of the carrier wave. A difference obtained from a first subtraction of the maximum value of the carrier wave from phase voltage commands of the maximum phase is set as a first differential. The first differential is subtracted from the phase voltage commands of the respective phases in a second subtraction. The first and second subtraction results are set as phase output voltage commands of the respective phases.

A three-phase DC motor output stage including a predriver that supplies drive voltages to power MOSFETs supplies output voltages to three-phase coils, monitors whether each of gate-to-source voltages of the power MOSFETs is greater than or equal to a predetermined voltage and thereby detects a current zero cross, and employs the output of such current zero cross detection in PLL control for controlling energization switching timing and thereby forms drive voltages of 180-degree energization. Lower hooks with a voltage minimum phase as GND and upper hooks with a voltage maximum phase as a source are set as patterns alternately repeated for every electrical angle of 60 degrees. The patterns are expressed in linear approximation to generate sine wave-like drive voltages, thereby causing sine wave-like currents to flow into the three-phase coils.

A filter circuit includes: an input terminal; a first resistance; a second resistance; a capacitor; and an output terminal, in which the first resistance, the second resistance, and the capacitor are connected in series in this order between the input terminal and a ground point, the output terminal is provided at a connection point of the first resistance and the second resistance, and a frequency domain is used that is higher than a maximum phase delay frequency higher than a cutoff frequency, the cutoff frequency being determined by a combined resistance value of the first and the second resistances and a capacitance value of the capacitor, so that when a frequency of an input signal becomes higher, a phase delay of an output signal relative to the input signal is reduced.

The invention discloses an amphibious robot propelled by undulating fins. The amphibious robot propelled by the undulating fins is characterized by comprising a robot body, driving arm units and the undulating fins; seven driving arm units are arranged on the left and right sides of the robot body; one ends of the driving arm units are connected with the robot body, and the other ends of the driving arm units are connected with the undulating fins; the undulating fins are formed by bending fan-shaped planes; a phase difference between the undulating fins connected with the two adjacent drivingarm units can be freely adjusted according to coordination between the driving arm units, and the maximum phase difference is 120 degrees; the driving arm units control the undulating fins to performsinusoidal undulation; the robot moves on the land through static friction forces between the undulating fins and the ground and moves underwater through the undulating fins and a counter-acting force of pushing water flow; and compared with a traditional amphibious robot, the amphibious robot propelled by the undulating fins has the advantages of simple structure, convenient control, high energyefficiency, low noise and high movement performance.

Methods and systems for receiving an optical signal using cascaded frequency offset estimation. Coherently detecting an optical signal includes compensating for a coarse laser frequency offset between a transmitting laser and a local oscillator laser by determining a maximum phase error (MPE) in the optical signal, compensating for a residual laser frequency offset between the transmitting laser and the local oscillator laser, and decoding data stored in the optical signal.

The invention belongs to an imaging method for nonlinear frequency modulation label change in the synthetic aperture radar imaging technology, which comprises the steps of two-dimensional frequency domain unfolding, filtering processing, nonlinear frequency modulation label change, distance compression, distance migration correction, rest phase compensation and position compression. In the method of the invention, the characteristics of orthogonality and minimum square error of the Legendre polynomials are utilized for carrying out three-order unfolding on the two-dimensional frequency domain signals of the obtained echo signals according to the Legendre orthogonality polynomials, and then, the focusing imaging on targets is realized through carrying out filtering processing and the like on three-order phase items in echo signal two-dimensional frequency domain expression. When the method of the invention is adopted, the maximum phase error under the same condition is less than 0.2 percent of the maximum phase error in the prior art, so the assurance is provided for the high-precision imaging under the large-inclination view angle condition. Therefore, the method of the invention has the characteristics that the phase error in the imaging process can be effectively reduced, the imaging processing of the large-inclination view angle is realized, in addition, the imaging effect is good, the imaging processing efficiency and the precision are high, and the like.

The invention discloses reference clock source switching method and device, wherein the reference clock source switching method comprises the following steps of: detecting a first phase difference between a local oscillator output clock of a system and a first reference clock source currently used by the system; acquiring the maximal phase difference between pairwise reference clock sources of a plurality of reference clock sources of the currently detected system; controlling the local oscillator output clock through the sum of the first phase difference and N / M times of the maximal phase difference; detecting a second phase difference between the local oscillator output clock and a second reference clock source when the system is switched to the second reference clock source; and controlling the local oscillator output clock through the difference of the second phase difference and (M-N) / M times of the maximal phase difference, wherein the plurality of reference clock sources include the first reference clock source and the second reference clock source, M and N are natural numbers, and M is larger than N. The invention can be used for effectively preventing anomalous events of the system clocks from happening after switching.

The invention relates to a method for selecting a fault phase of an alternating current transmission line by using transient energy. The method comprises the following steps of: when the alternating current transmission line fails, extracting a fault component of a three-phase current travelling wave after the fault, and constructing zero mode current and line mode current; performing wavelet transform on phase current and mode current respectively, and solving the transient energy; if the energy value of a zero mode is less than 1 percent of the maximum mode energy value, determining that the fault is a phase-to-phase fault, and otherwise, determining that the fault is an earth fault; if the energy value of a certain phase current is more than 20 percent of the maximum phase current energy value, determining that the fault is the fault phase; and if the fault is the phase-to-phase fault and the energy values of the other two-phase current are less than 20 percent of the maximum phasecurrent energy value, determining that the fault is a three-phase fault. In the method, a phase selection judgment basis is relatively simple, has relatively high applicability to transition resistance and fault initial angles, and can provide a correct basis for the tripping of a breaker in the consideration of combined reclosing at any fault initial angle.

A method for detecting a magnetizing inrush current of a transformer includes the steps of obtaining a difference current for each AC phase of a transformer and calculating, for each AC phase, at least two factors for waveform symmetry recognition, on the basis of the difference currents obtained within one period. For each type of factor, one obtains the maximum value of the three factors corresponding to the three AC phases, to serve as a maximum phase factor of that factor. Based on the maximum phase factor obtained, a waveform symmetry recognition algorithm is used to calculate a corresponding waveform symmetry parameter, and if the waveform symmetry parameter meets a requirement for waveform asymmetry, then it is determined that a magnetizing inrush current has occurred. A device for protecting the transformer is further provided.

Digitally controlled delay-locked loops can have a phase detector, control logic, and a delay chain. The control logic generates digital signals in response to an output signal of the phase detector. The delay chain generates a delay that varies in response to the digital signals. In some embodiments, the control logic maintains logic states of the digital signals constant in response to an enable signal to maintain the delay of the delay chain constant in a lock mode of the digitally controlled delay-locked loop. In other embodiments, the delay of the delay chain varies by a discrete time period in response to a change in logic states of the digital signals, and the maximum phase error between a phase of the reference clock signal and a phase of the feedback clock signal is less than the discrete time period when the digitally controlled delay-locked loop is in a lock mode.

A spatial terahertz wave phase modulator based on the high electron mobility transistor is provided. The phase modulator combines the quick-response high electron mobility transistor with a novel metamaterial resonant structure, so as to rapidly modulate terahertz wave phases in a free space. The phase modulator includes a semiconductor substrate, an HEMT epitaxial layer, a periodical metamaterial resonant structure and a muff-coupling circuit. A concentration of 2-dimensional electron gas in the HEMT epitaxial layer is controlled through loading voltage signals, so as to change an electromagnetic resonation mode of the metamaterial resonant structure, thereby achieving phase modulation of terahertz waves. The phase modulator has a phase modulation depth of over 90 degrees within a large bandwidth, and a maximum phase modulation depth is about 140 degrees. Furthermore, the phase modulator is simple in structure, easy to machine, high in modulation speed, convenient to use, and easy to package.

In a power conversion device that includes a PWM converting means for generating a PWM pulse by comparing three-phase voltage commands with a triangular wave carrier signal, a power converter for converting between a DC voltage and a three-phase AC voltage by driving a switching element according to the PWM pulse, a current detecting means for detecting a pulsed current flowing through a DC bus conductor of a main circuit, and a voltage command correcting means for correcting three-phase voltage commands, which corrects the three-phase voltage commands so that a line voltage value between the maximum phase and an intermediate phase and a line voltage value between the intermediate phase and the minimum phase are each equal to or larger than a predetermined value, the maximum phase, intermediate phase, and minimum phase being determined in correspondence to momentary values of the three-phase voltage commands arranged in descending order, if the voltage command is outside an allowable upper limit or lower limit, not only the voltage command for the maximum phase and / or the minimum phase but also the voltage command for the intermediate phase are corrected.Accordingly, the inability to detect a current due to a restriction imposed by an upper limit or a lower limit for an output voltage is eliminated, and highly precise control of the power conversion device is achieved independently of the situation.

A piezoactuator has a diaphragm, and the diaphragm has flat piezoelectric elements that oscillate in a longitudinal oscillation mode and a sinusoidal oscillation mode. A first electrode for detecting oscillation in the longitudinal oscillation mode, and a second electrode for detecting the amplitude of oscillation in the sinusoidal oscillation mode, are disposed on the surface of the diaphragm. When the piezoactuator is driven with a drive signal, the phase difference of a first detection signal output from the first electrode and a second detection signal output from the second electrode is detected. The frequency at which the detected phase difference becomes the maximum phase difference is then obtained, and a drive signal of a matching frequency is applied to the piezoelectric elements.

General encoder and Hall component or increment type encoder capable of transmitting U, V, W signals are installed on rotor. U, V, W signals divide electrical angle of rotor position into six intervals in 60 degrees each. At strating up time of power on, magnetic vector intervals of rotor are determined through U, V, W signal states. The middle point of the interval is as position of magnetic vector of rotor. Controller outputs electrical current to three-phase winding of stator. Maximum phase error of current is only 30 degrees. When rotating rotor steps across interval, first change of U, V, W signal states occurs. Thus, accurate positioning for rotor is carried out, and normal operation begins. System checks position of rotor in every 60 degree in order to avoid positioning error in operation.

The invention discloses an excitation surge current detection method and device. The method comprises the following steps: obtaining differential current ix(n) of each alternating-current phase of a transformer; for the alternating-current phase, based on the differential current sampled in a cycle, calculating at least two factors (Ax(n), Bx(n)) used for waveform symmetry judgment; for each factor, obtaining a maximum value of three factors corresponding to three alternating-current phases as a maximum phase factor of the factors; based on the obtained maximum phase factor, calculating a corresponding waveform symmetry coefficient kmax by a waveform symmetry judgment algorithm; if the waveform symmetry coefficient kmax meets the waveform asymmetry requirement, determining that excitation surge current is generated.

The invention relates to the technical field of variable frequency control, in particular to a current sampling method for a frequency converter, comprising: when performing current sampling during phase sampling, detecting and sequencing the phases of a three-phase voltage, and determining a voltage maximum-phase signal, a voltage middle-phase voltage and a voltage minimum-phase signal; performing current sampling of the current vector information corresponding to the voltage middle-phase signal and the current vector information corresponding to the voltage minimum-phase signal, wherein thecurrent vector information corresponding to the voltage maximum-phase signal is an inverted phase of the sum of the current vector information corresponding to the voltage middle-phase signal and thecurrent vector information corresponding to the voltage minimum-phase signal. In the method provided by the invention, the problem that a current sampling dead zone exists in two recent sampling modes is solved, and synchronously current sampling precision is guaranteed by adopting a two-phase PWM (pulse-width modulation) modulation mode.

Provided is a data recovery circuit including an input data phase detection circuit for outputting a gate signal synchronized with a rising phase of input data, a gated multiphase oscillator for instantly generating N-phase clocks based on the gate signal as a trigger, data discriminating and reproducing circuits for outputting sampled data of the input data which are synchronized with the clocks, a continuous clock generation circuit for generating a continuous clock which is a reference clock, continuous clock synchronization circuits for synchronizing the sampled data with the continuous clock and outputting the synchronized sampled data as phase synchronization data, and a phase selector for selecting the phase synchronization data having an optimum discrimination phase with the largest phase margin with respect to the input data and outputting the selected phase synchronization data as recovery data.

An apparatus and method for implementing an equalizer which (1) combines the benefits of a decision feedback equalizer (DFE) with a maximum-a-posterori (MAP) equalizer (or a maximum likelihood sequence estimator, MLSE) (2) performs equalization in a time-forward or time-reversed manner based on the channel being minimum-phase or maximum-phase to provide an equalization device with significantly lower complexity than a full-state MAP device, but which still provides improved performance over a conventional DFE. The equalizer architecture includes two DFE-like structures, followed by a MAP equalizer. The first DFE forms tentative symbol decisions. The second DFE is used thereafter to truncate the channel response to a desired memory of L1 symbols, which is less than the total delay spread of L symbols of the channel. The MAP equalizer operates over a channel with memory of L1 symbols (where L1<=L), and therefore the overall complexity of the equalizer is significantly reduced.

The invention discloses a switched reluctance motor flux linkage characteristic measurement method, which includes the following steps: a position sensor is calibrated, and the coefficient of a measuring circuit is determined; a load is removed, a switched reluctance motor is operated, and the switching angle is adjusted, so that the phase current of the motor is similar to the shape of a flat-topped wave; the direct-current voltage is decreased, so that the peak value of the phase current is as small as possible, and a data matrix is sampled and stored; the direct-current voltage is increased, so that the peak value of the phase current is slowly increased; the load is added, the turn-on angle or the turn-off angle is changed, a needed data set is detected, and the data are sampled and stored; and the peak value of the current is gradually increased until reaching the upper limit of the current allowed by the motor, and data vectors are recorded under different currents until the maximum phase current reaches a maximum current imax needing a current peak value. The whole process of the method only uses the conventional switched reluctance motor speed regulation system and the conventional storage type digital oscilloscope, and does not need a specialized mechanical rotor positioning and clamping device, and the measuring equipment can be easily obtained.