33results about How to "Avoid phase error" patented technology

The invention belongs to the field of underwater acoustic transducers, in particular to a method for measuring the amplitude and phase consistency of a linear hydrophone array. The invention includes mechanically fixing the hydrophone array on the lifting device, the lifting device lifts the hydrophone array up and down at a fixed interval, hangs the transmitting transducer at a certain distance from the hydrophone array, and the distance meets the requirements of the transducer. The far-field distance from the hydrophone, the hanging depth of the transmitting transducer is the same as the depth of the hydrophone at the top of the hydrophone array; the hydrophone array and the lifting device are mechanically fixedly connected, during the lifting process, the hydrophone array Always remain vertical with no horizontal wobble or movement. The invention adopts the method of moving the hydrophone in the vertical direction, which avoids the phase error caused by the distance error in the horizontal direction caused by moving the hydrophone in the horizontal direction or re-hanging the hydrophone during the consistency measurement of the traditional hydrophone.

A synthetic aperture radar polar format algorithm based on scaling principle comprises the following steps of : constructing a data collection geometric model of spotlight synthetic aperture radar; carrying out range-dimension processing pulse by pulse, inputting time-domain echo signals, subjecting the time-domain echo signals to range scaling to obtain output signals, i.e. range frequency domain signals achieving range re-sampling; processing the range frequency domain signals (scaling and focusing) to obtain an azimuth-focused image while achieving azimuth scaling (azimuth re-sampling); and subjecting the azimuth-focused data to fast Fourier transform in range dimension to obtain a two-dimensional focused image. The invention can achieve re-sampling by using two-dimensional transformation to substitute for two-dimensional interpolation in conventional PFA algorithm. The method only needs FFT and complex multiplication operation, and the computation efficiency can be improved significantly. Meanwhile, the possible phase error resulting from the finite interpolation kernel length can be obviated.

The invention discloses a circular antenna array design method for a rotation circular polarization array element to produce an OAM beam. The design method comprises the steps that 1 the antenna center frequency f is given, and the structure of a single array element is determined and optimized to generate circular polarization waves; 2 N array elements determined in the step 1 are equidistantly arranged along the circumference into an initial uniform circular array antenna; 3 feed excitation of the same phase is carried out on each array element in an initial circular array, and codirectionalrotation at a specific angle is carried out to acquire a rotated circular antenna array; and 4 the radius of the circumference of the rotated circular antenna array is adjusted, so that the field phase diagram of the rotated circular antenna array presents a spiral phase wavefront and the OAM beam is produced to acquire the final circular antenna array. According to the invention, multiple phaseshifters of different lengths are not needed; the design of a feeding network is simplified; and a phase error introduced by each phase shifter is avoided.

The invention relates to a laminated scanning based phase-difference wavefront detection and image restoration method which can be used for restoring wavefront distortions and capable of effectively restoring blurred images affected by aberrations. According to the method, a small-aperture diaphragm is moved within a pupil plane of an imaging system in a laminated scanning mode, and corresponding sub-images affected by different aberrations are recorded by using an image sensor. The recorded series of sub-images are processed by using the laminated scanning based phase-difference wavefront detection and image restoration method, and wavefront distortions of the system can be detected and the images can be restored. The method adopts the small-aperture diaphragm to perform space scanning so as to produce the sub-images having phase differences. Compared with various existing technologies for phase difference methods, the Nyquist sampling frequency is more easily met, an aberration detection range is large, out-of-focus light paths and various diffraction devices are not needed, and the laminated scanning based phase-difference wavefront detection and image restoration method has the advantages of being compact in system, convenient to use and the like.

The present invention provides a beam direction switching method and device based on a microphone array, and the method comprises the steps: determining phase delay information between microphones inthe microphone array; acquiring sound source signals collected by all microphones in the microphone array; performing beam forming of the sound source signals collected by the microphones to obtain output signals of the microphone array in the preset all beam directions; determining a target beam direction from the fixed beam directions according to the energy values of the output signals of the microphone array in the fixed beam directions; switching the beam direction of the microphone array to the target beam direction. The method can select an optimal beam direction from the preset fixed beam directions according to the position of a user, can enable the determined beam direction to adapt to the mobility of the user, and improves the applicability of the method.

The invention provides a permanent magnet synchronous motor rotor location full-order sliding mode observation device and method. The device comprises a full-order sliding mode observer, a saturationfunction processing module and a phase-locked loop module; in the method provided by the invention, an observation value as shown in description of the stator current can be output after the stator voltage us of the permanent magnet synchronous motor processed through a full-order sliding mode observer; the current error as shown in description is obtained after making the difference processing onthe value as shown in description and the stator current value is; a sliding mode function control vector F(S) is output after the value as shown in description processed through the saturation function processing module; the sliding mode function control vector F(S) in the saturation function processing module adopts a hyperbolic tangent function with adjustable boundary layer thickness, the adjusting of the boundary layer thickness is performed according to the rotating speed self-adaptive law of the switch gain gr, the counter electromotive force observation error as shown in description is obtained after the FS processed through a sliding mode gain matrix G1, the back counter observation value as shown in description is output after the value as shown in description processed througha full-order sliding mode observer; the value as shown in description is served as a state variable to be fed back to the full-order sliding mode observer to participate the update computation; a permanent magnet synchronous motor rotor location observation value as shown in description and the rotating speed observation value as shown in description are output after the value as shown in description is processed through the phase-locked loop module.

The invention discloses a rail traffic axle counting system based on FPGA phase detection. The rail traffic axle counting system comprises a first wheel sensor arranged on one side of a rail and a second wheel sensor arranged on the other side of the rail, the first wheel sensor and the second wheel sensor are connected with a control room through axle counting equipment, and the axle counting equipment comprises a first FPGA, a first conditioning circuit, a second FPGA and a second conditioning circuit. The first FPGA generates a pulse signal with the frequency f1 and sends the pulse signal to the first wheel sensor through the first conditioning circuit, and a signal returned by the first wheel sensor is connected to the first FPGA through the first conditioning circuit to be subjected to data processing. The second FPGA generates a pulse signal with the frequency f2 and sends the pulse signal to the second wheel sensor through the second conditioning circuit, and a signal returned by the second wheel sensor is connected to the second FPGA through the second conditioning circuit to be subjected to data processing. The first FPGA and the second FPGA sends the counting results to the control room. The debugging efficiency is improved, and the rail traffic axle counting system is suitable for a train travelling at a high speed.

The invention relates to a magnetically-controlled reactor control system which comprises a low-voltage part and a high-voltage part, wherein the low-voltage part comprises an upper industrial computer, an LCD touch screen, a main controller, a wireless communication master station and a relay protection device, and is used for detecting voltage and current signals, completing the control function via a control target and sending firing angle data to the high-voltage part in a wireless communication manner; and the high-voltage part comprises an excitation controller A, an excitation controller B and an excitation controller C, and is used for receiving the firing angle instruction sent out by the low-voltage part in a wireless communication manner, and uploading the fault information and control winding voltage to the main controller of the low-voltage part. The magnetically-controlled reactor control system is safe and reliable in insulation of high-voltage part and low-voltage part, is easy to implement, and reduces equipment cost and field construction workload; through synchronous signals provided by the control winding, control accuracy and stability are improved; and under the situation that a hardware platform is basically unchanged, requirements of various application occasions can be met through only selecting and assembling a small quantity of hardware and software modules.

A power clipping circuit and method of the clipping circuit is provided. A power clipping circuit comprises, a selector which receives a baseband signal, and selects one of the baseband signal or a feed back signal, and outputs a selected signal, and a square clipping circuit which receives the selected signal, and limits an amplitude of the selected signal, and outputs a clipped signal, and a phase rotation circuit which receives the clipped signal, and rotates a phase of the clipped signal, and outputs a phase rotated signal to the selector as the feed back signal, and an amplitude scaling circuit which receives the phase rotated signal, and adjust the phase rotated signal to compensate an amplitude difference between the phase rotated signal and the clipped signal, and sends amplitude scaled signal, and a controlling circuit which controls the selector, the square clipping circuit, the phase rotation circuit and the amplitude scaling circuit.

According to the broadband CMOS second-order active balun amplifier, a series structure of two stages of active balun is used, higher phase precision is obtained, and the requirement for high loss ofa radio frequency circuit is met. Phase shift in the transmission process from a signal source to a load is eliminated through the input pi-type matching circuit, and 50-ohm input impedance matching is achieved; the first-stage active balun circuit and the second-stage output active balun circuit are in cross coupling connection through a capacitor, and the first-stage active balun circuit uses abroadband phase correction technology to obtain Vo1 and Vo2 with small phase errors and gain errors; according to the second-stage active balun circuit, two double-end-to-single-end baluns are used asoutput ends, a traditional source follower is replaced as a buffer, the phase precision is improved through phase compensation between signals, and meanwhile output matching is achieved. The invention can be used for an active balun amplifier of 1-8GHz.

The invention provides a method for measuring electrode current through an electrode current measuring device for low voltage compensation of a submerged arc furnace. The method for measuring the electrode current comprises the following steps that a Rogowski coil output signal is a differential voltage signal of primary current; a first summing integrator performs vector summing integration on the signal to obtain capacitance compensation current; a second summing integrator performs vector summing integration on the signal to obtain furnace transformation low-voltage-side current; the capacitance compensation current and the furnace transformation low-voltage-side current are sent to a first adder and subjected to vector subtraction calculation to obtain compensated current on a short net behind a low voltage compensation access point; the compensated current is sent to a second adder; and front-phase compensated current is sent to the current-phase second adder, and is subtracted from the current-phase compensated current to obtain current-phase electrode current. The method has the characteristics of accurate measurement, wide measurement range, convenience for installation and simple structure.

The invention discloses a multiple-input multiple-output imaging radar for slope monitoring, and the radar is characterized in that the radar comprises a microstrip array antenna comprising M transmitting array antennas and N receiving array antennas, a frequency modulation continuous wave radar radio frequency front-end module, an ADC module, a data storage module, a data conversion module, a radar signal processing module and an external data interaction interface module; an electromagnetic wave signal reflected by a slope is received by the microstrip array antenna and is processed by the frequency modulation continuous wave radar radio frequency front-end module to output an intermediate frequency signal, and the radar signal processing module receives the intermediate frequency signal converted and output by the ADC module and performs digital signal processing on the intermediate frequency signal to complete slope imaging; the side slope image is compared with the reference side slope radar image stored in the data storage module to judge whether the side slope is deformed or not; and the external data interaction interface module outputs a slope image monitoring result to the outside. The device is small in size, convenient to install and maintain, high in image acquisition speed and low in cost.

A circuit breaker for a low-voltage circuit is disclosed. In an embodiment, the circuit breaker includes a current conductor, assigned a measuring transducer for measuring the electrical current of the current conductor; a first filter connected to the measuring transducer; an analog / digital converter connected to the first filter; a second, high-pass filter connected to the analog / digital converter; and a digital integrator, connected to the high-pass filter and configured to determine the electrical current of the current conductor.

Provided is a phase encoding cross-polarization synthetic aperture laser imaging radar which comprises a laser light source, a fiber polarization beam splitter, a first optical phase modulator, a second optical phase modulator, a microwave signal waveform generator, a microwave amplifier, a first fiber collimator, a second fiber collimator, a first along-rail cylindrical lens, a second along-rail cylindrical lens, a emission polarization beam combiner, an emission primary mirror, a receiving telescope, a receiving half-wave plate, a receiving polarization beam splitter, a reflector, a balance detector, an A / D converter, and a signal acquiring and processing computer. The phase encoding cross-polarization synthetic aperture laser imaging radar have same advantages with an orthophoria synthetic aperture laser imaging radar, is not provided with a moving optical element so as to avoid errors and noise of mechanical elements for driving an optical element to move, uses reciprocal half-code phase modulation, reduces voltage values loaded onto the optical phase modulators, changes the encoding speed of the microwave signal generator, namely changes the system cross-rail resolution, and is high in flexibility.

The invention discloses a control method for flexible mutual switching of an inverter and a power grid, belongs to the technical field of power grids, and is used for smoothly switching a motor between two working modes of inverter driving and power grid driving. According to the invention, the software interlocking of the bypass contactor and the inverter input contactor is ensured through the self-adaptive measurement of the mechanical action characteristic parameters of the direct current contactor and the auxiliary contact action logic of the contactor, so that the time delay defect of repeated charging of the direct current support capacitor in the switching process is overcome; and the inter-switching time of the inverter and the power grid is minimized, namely flexible inter-switching is realized, and the current impact in the inter-switching process is reduced to the minimum. The method does not need an electric reactor, reduces the number of contactors, and has the advantages of being easy to implement, low in cost, wide in application range and the like.

The invention provides a novel position sensor-free starting method for a permanent-magnet synchronous motor. The novel position sensor-free starting method comprises the following steps of S1, building a mathematical model of the permanent-magnet synchronous motor (PMMS); S2, under an ideal condition, acquiring a stator voltage equation of the projection of the PMSM on a dq axis through a statorvoltage vector equation of a two-phase winding of the PMSM under a rotating coordinate system; and S3, acquiring a voltage equation under a gamma-delta coordinate system based on a combination of thestator voltage equation and an included angle phi between a delta axis and a q axis in the PMSM mathematical model in the S1, wherein the equations are as defined in the specification. The novel position sensor-free starting method for the PMMS provided by the invention has the advantages that I / F control can be introduced at a zero speed and low speed of a motor so as to overcome the condition oflow observation accuracy of a sliding mode observer at the zero speed and low speed, and an optimization algorithm is stably switched to sliding mode control when the motor has a certain initial speed.

The invention discloses a simulation navigation satellite signal stray suppression method. According to the method, a plurality of linear feedback shift register groups are adopted, the generated jitter signal does not have a single periodicity, and the jitter is more noisy, so that the effect of improving the stray is more obvious; and the plurality of jitter sequences are added to the low levelof the phase words, the phase noise introduced by jitter is prevented from being larger than the phase error generated by quantization, and therefore the phase resolution of the signal is prevented from deteriorating.

The invention discloses a linear interval expansion method for rapid frequency locking and cycle slip elimination, which comprises the following steps: dividing a phase discrimination interval into a plurality of linear subintervals with the length of 2[pi], and when the phase deviation exceeds + / -[pi], carrying out linear expansion, enabling the phase frequency detector for linear expansion and the charge pump to output constant current representing + / -2[pi] and convert a phase discrimination interval into a phase opposite to the phase discrimination interval so as to ensure that the output current is correct and neglect phase error information of + / -2[pi] so as to thoroughly avoid generation of cycle slip. According to the invention, the cycle slip phenomenon can be fundamentally avoided. A linear phase discrimination interval is expanded to + / -16[pi], and meanwhile, the number of branches of a constant current source is increased for further expansion, so that the expansion of the linear interval does not cause a metastable state.

The invention provides a silver nanometer column enhanced double-core light intensity modulator based on graphene. The optical fiber is characterized by consisting of a double-core optical fiber 1, input and output port couplers 2-1 and 2-2, graphene layers 3-1 and 3-3 respectively deposited on the surfaces of left and right side polished optical fibers, graphene layers 3-2 and 3-4 respectively deposited on the top layers of left and right side aluminum oxide films, transition material aluminum oxide films 4-1 and 4-2 between graphene, silver nanorods 5-1 and 5-2 on the top layers, and an optical fiber coupling layer 3-1 and 3-3 respectively deposited on the surfaces of the left and right side polished optical fibers, the graphene layers 3-2 and 3-4 respectively deposited on the top layers of the left and right side aluminum oxide films, the transition material aluminum oxide films 4-1 and 4-2 and the silver nanorods 5-1 and 5-2 on the top layers. The electrode materials 6-1 and 6-3 which are in contact with the lower-layer graphene on the two sides, the electrode materials 6-2 and 6-4 which are in contact with the upper-layer graphene on the two sides, the two incident ports 7-1 and 7-2 and the two emergent ports 7-3 and 7-4 are placed end to end. Graphene has the characteristic of adjustable carrier concentration, two sides of the graphene are externally connected with different voltages respectively, different effective refractive index change conditions of double cores in the polished optical fiber 8 can be realized, and linear modulation of light intensity is realized at a tail port through coupling. The dual-port light intensity modulation device can be widely applied to the field of dual-port light intensity modulation in optical fiber communication.