61results about How to "Improve response bandwidth" patented technology

The invention discloses a high-precision fiber frequency transmission system, and the system comprises a PID circuit board, a phase discriminator, a photoelectric detector, a Faraday rotary reflector, a microwave photon phase shifter, a 2*2 optical coupler, a circulator, a slave laser, a frequency reference signal source, a main laser emitter, an isolator, an optical fiber link, and a time frequency receiving and transmitting module. On the basis of a single-fiber bidirectional return error signal obtaining mode, the system carries out the optical fiber link noise compensation based on injection locked coherent detection and the microwave photon phase shifter, thereby achieving the high-precision fiber frequency transmission. The system can achieve the high-precision recovery of a frequency reference signal of a local end at a far end. The system can achieve the two features, needed by phase change, on the same microwave photon phase shifter at the same time: large-bandwidth response and large dynamic range, facilitates the reduction of the complexity, and improves the stability and adaptability. The system can be used in the fields of comparison of the optical clock/atomic clock and the frequency transmission.

A dynamic load fixture (DLF) applies a torsion load to a unit under test (UUT) to achieve the demanding aerodynamic load exposures encountered by a control actuation system (CAS) in flight. Instead of fixing the end of the torsion bar, the DLF controls the application of torque to the torsion bar, hence the UUT via a DLF motor. The dynamic load can be independent of the angular rotation of the UUT, which allows the DLF to more effectively reproduce desired acceptance tests such as torque-at-rate and nonlinear loads. Furthermore, application of the loads through a torsion bar allows the system the compliance needed to generate precise loads while allowing for the flexibility of changing torsion bars to test a wide variety of UUT on one test platform. To achieve the demanding aerodynamic load exposures encountered by a CAS in flight, the controller must be able to respond both very fast and very precisely. Control is enhanced by the thorough characterization of the DLF and application of either “classic” negative feedback control or “modern” state-space control methods of linear observers and quadratic optimum control.

The invention belongs to the technical field of intelligent processing and manufacturing, and particularly discloses an integrated active-passive compliant one-dimensional variable force grinding andpolishing device and a control method. The integrated active-passive compliant one-dimensional variable force grinding and polishing device comprises a linear module servo motion platform, a mountingflange, a limiting plate, a position and orientation sensor, a speed-adjustable compliant grinding and polishing mechanism and a controller, and the linear module servo motion platform is used for driving the grinding and polishing mechanism to perform linear motion; the mounting flange and the limiting plate are mounted on a base of the linear module servo motion platform, and the position and orientation sensor and the speed-adjustable compliant grinding and polishing mechanism are installed on the limiting plate; and the position and orientation sensor is used for measuring position and orientation of the one-dimensional variable force grinding and polishing device and sending the position and orientation to the controller, a force sensor is arranged between the compliant grinding and polishing mechanism and sliding blocks, the force sensor is used for collecting a contact force signal and send to the controller which can calculate speed control quantity, and the speed-adjustable compliant grinding and polishing mechanism is driven to move by rotation of a servo motor according to the speed control quantity. According to the integrated active-passive compliant one-dimensional variable force grinding and polishing device and the control method, the contact status of a abrasive belt and a workpiece can be adjusted in real time, and a stable and compliant grinding and polishingprocess is realized.

A dynamic load fixture (DLF) for testing a unit under test (UUT) includes a lateral load system that applies a time-varying lateral load profile to the UUT drive shaft and an encoder that measures its angular rotation. An isolation stage suitably constrains the encoder from rotating about the axis while allowing it to move in other directions in which the application of the lateral force induces motion. The lateral load system includes a load bearing around the drive shaft, an actuator that applies a lateral force to the load bearing, a force sensor for measuring the applied lateral force, and a lateral controller for adjusting a command signal to the actuator to implement a lateral load profile. The DLF may also include a torsion load system that applies a time-varying torsion load profile to the drive shaft.

The invention discloses a high-power ultrashort-pulse optical frequency comb generation method based on a self-similar amplifier. The high-power ultrashort-pulse optical frequency comb generation method is based on self-similar amplification technology and effectively overcomes gain narrowing, bandwidth limitation and nonlinear phase distortion in pulse amplification. A light spectrum is effectively expanded, and the bandwidth of an output pulse is reduced. Furthermore the power of a mode-locked pulse is effectively expanded, thereby acquiring a high-power femtosecond pulse and improving carrier envelope phase zero-frequency locking precision. Furthermore carrier envelope phase zero-frequency locking technology based on an acoustic-optical crystal frequency shifter is utilized, thereby realizing large reaction bandwidth and high control precision, and realizing a high-frequency high-power ultrashort-pulse optical frequency comb through real-time control. The high-power ultrashort-pulse optical frequency comb generation method is advantageous in that the high-power ultrashort-pulse optical frequency comb generation method can be directly expanded and applied on femtosecond optical frequency comb control technology for obtaining the stable high-frequency high-power ultrashort-pulse optical frequency comb.

A distributed fibre sensing system and a vibration detection and positioning method therefor are disclosed. The system comprises: a signal generating module, a light source module, an optical frequency comb generating module, a frequency sweeping and pulse generating module, an optical circulator, a sensing fibre, an interference module, a photoelectric conversion module and a detection and position module. The method comprises: obtaining a plurality of Rayleigh backscattering signals of the sensing fibre; performing a fading elimination processing on the Rayleigh backscattering signals, thereby obtaining a plurality of averaged Rayleigh backscattering signals of non-interference fading and polarization fading; performing a phase processing on the averaged Rayleigh backscattering signals, thereby obtaining phase variance curves; and determining a vibration point according to variances in the phase variance curves, and finally obtaining a position and a vibration waveform of the vibration point.

The invention provides a follow-up control method by means of fractional-order quick terminal sliding mode control. The follow-up control method includes receiving angle instructions, extracting follow-up angle feedback, computing first-order derivatives, second-order derivatives and third-order derivatives of the instructions and computing first-order derivatives and second order-derivatives of the angle feedback; computing angle control errors and first-order derivatives and second-order derivatives of the angle control errors; computing first-order derivatives of fractional-order quick terminal sliding mode surfaces and non-singular quick terminal sliding mode surfaces of position loops; computing fractional-order terminal sliding mode control quantities and current loop instructions offollow-up systems; acquiring line currents, computing alternating and direct shaft currents of PMSM (permanent magnet synchronous motors) in dq coordinates and inputting dq shaft voltage control quantities for inverse park transformation on the PMSM to control the motors. The follow-up control method has the advantages that the systems are excellent in dynamic response capacity, and static positioning and dynamic tracking precision requirements can be met.

The invention provides a miniature diaphragm type optical fiber end FP pressure sensor, a manufacturing method and application. The miniature diaphragm type optical fiber end FP pressure sensor includes an optical fiber, a hollow core optical fiber and a pressure-sensitive diaphragm, wherein the optical fiber and the hollow core optical fiber have the same diameters and the two are welded by arcs;and the pressure-sensitive diaphragm is bonded on the end surface of the hollow core optical fiber by using a hydrogen-oxygen catalytic bonding method. The entire quartz structure of the sensor can be realized, the existence of organic polymers at the joints of the elements is eliminated, and long-term stability and thermal stability are extremely high. The manufacturing method improves the applicable range and the service life of the sensor and the manufacturing cost is also reduced. The sensor provided in the invention can be applied to monitoring of parameters such as pressure and sound waves in extreme environments such as high temperature, high pressure, and strong corrosion, and can also be used for pressure measurement in the case of limited human body space in the medical and clinical field.

The invention relates to a drive control system and method for a control moment gyro outer frame. The drive control system comprises a position detection module used for detecting the position information of the control moment gyro outer frame; a current detection module used for detecting two-phase current information of a control moment gyro outer frame motor; a position control module used forreceiving a position control signal and outputting a speed control signal according to the position information detected by the position detection module; a speed control module used for receiving a speed control signal and outputting a current control signal according to the position information detected by the position detection module; and a current control module used for receiving a current control signal and carrying out drive control on the control moment gyro outer frame according to the two-phase current information detected by the current detection module and the position informationdetected by the position detection module. The control system and the control method not only improve the accuracy of the system, but also greatly improve the reliability and response width of the system.

The embodiment of the invention discloses a dual-motor synchronous control device and method, relates to the technical field of electromechanical control, and can improve dual-motor synchronous control precision and reduce the response period of a speed loop and a current loop of a master-slave motor servo system. The method is characterized in that an embedded controller, an FPGA controller, a master motor driving circuit, a slave motor driving circuit, a master motor, a slave motor, a master motor sensor and a slave motor sensor are included, wherein the embedded controller is connected withthe FPGA controller through a bus, the FPGA controller is connected with the master motor driving circuit and the slave motor driving circuit, the master motor is connected with the master motor driving circuit, the master motor sensor is connected with the master motor, the slave motor is connected with the slave motor driving circuit, and the slave motor sensor is connected with the slave motor. The method is advantaged in that the method is suitable for a dual-motor synchronous control system.

A high speed optical switch into relating polarization is disclosed whose characteristics is its structure: the driving device includes by circular mirror comprising of the third terminal port and the forth terminal port on one side of a coupler connecting together and a controlling device being put into the circular mirror ; the first terminal port of the is connecting to the second terminal port of three terminal ports circulator whose first terminal port is input terminal and the third terminal port is the first output terminal of the switch, the second terminal port is the second output terminal; the coupler circulator and circular mirror are all fixed on one. The advantages are rapid response speed, unconcerned to polarization and broad band response, simple structure, reliable and stable operation.

An LED visible light communication system based on OFDM relates to a visible light communication technology. The LED visible light communication system of the invention is used for solving the problem that transmission speed rate is low and the anti-jamming capability is weak because the visible light communication system is simple in design. A pre-equalizing circuit is used for compensating distortion brought by a system via a device and a channel so as to extend a response bandwidth of an LED array, and an OFDM modulator circuit takes full advantage of existing bandwidth to improve transmission rate. A photoelectric module is used for converting the received optical signal into an electric signal; a signal processing circuit is used for obtaining an obvious characteristic signal after processing the input electric signal. A communication protocol is used for solving the problems of a transmitting and receiving acknowledgement mechanism, a message read-write mechanism, a time sequence matching mechanism. By using an OFDM modulation technique as basis, and using DSP digital information processing technique as core, the LED visible light communication system of the invention improves the transmission speed rate. The pre-equalizing circuit and a post-equalizing circuit improve the anti-jamming capability of the system. The LED visible light communication system of the invention could be applied to visible light communication of an LED.

The invention provides a device and a method of evaluating time domain stability of a high-power optical fiber laser system. The device comprises a to-be-detected high-power optical fiber laser system, a wavelength-tunable ultralow noise optical fiber laser, a wavelength division multiplexer, an energy transfer optical fiber, a collimator, a bandpass filter, a power meter and a waste light collector. Through analyzing the dependency relationship between the conversion efficiency of Raman amplification laser with the central wavelength of lambda2 and the time domain stability of pumping laser with the central wavelength of lambda1 and through measuring the output power of Raman amplification signal light, the Raman conversion efficiency is further calculated and then compared with the Ramanamplification light power and the conversion efficiency which are calculated and obtained in a no-time domain undulation ideal condition, and thus, the time domain stability of the to-be-detected high-power optical fiber laser system can be evaluated. The time domain stability of the high-power optical fiber laser system can be evaluated based on a pure optical detection method, and problems suchas limited bandwidth and high system cost existing in the traditional photoelectric detection method can be avoided.

The invention provides a uni-traveling-carrier photodetector structure and a manufacturing method thereof. A photodetector structure with a collection layer area smaller than an absorption layer area is manufactured by utilizing a stepwise corrosion method, so that device capacitance is greatly reduced, the RC response bandwidth of a device is increased under the condition of the same absorption layer thickness, and the total bandwidth of the device is increased; the device has a larger absorption layer area under the condition of the same absorption layer area and the same absorption layer thickness (the RC bandwidth and the transition bandwidth are same), so that the device has a higher response degree and can work under higher incident power, and the performance improvement is more remarkable in high-speed high-power application; and therefore, the photodetector structure is suitable for the fields of terahertz signal generation, light receiving in high-speed light communication, and the like.

The invention provides a Bragg grating, a preparation method thereof and a distributed feedback laser, and belongs to the technical field of semiconductor lasers. The Bragg grating is arranged in a distributed feedback laser. The Bragg grating comprises a lower grating waveguide layer, a middle grating waveguide layer and an upper grating waveguide layer which are sequentially formed and have different refractive indexes; the refractive index of the middle grating waveguide layer is lower than the refractive index of the lower grating waveguide layer and the refractive index of the upper grating waveguide layer; the doping types of the lower grating waveguide layer and the middle grating waveguide layer are the same; the doping type of the upper grating waveguide layer is opposite to the doping types of the adjacent layers, so that a reverse biased PN junction can be formed on the upper grating waveguide layer; a plurality of grooves are formed in the upper grating waveguide layer at intervals in the cavity length direction of the distributed feedback laser; and the grooves are filled with buried layers to flatten the upper grating waveguide layer. The coupling coefficient of the Bragg grating can be increased along with the increase of the current of the distributed feedback laser, so that the cavity loss of the distributed feedback laser is reduced, and the response bandwidthis expanded.

The invention belongs to the field of grinding and polishing force control, and discloses a full-digital rigid-flexible coupling precise force controlled grinding and polishing device. The grinding and polishing device comprises a speed-variable flexible grinding and polishing mechanism, a one-dimensional linear module force control servo motion platform and a connecting device used for connectingthe speed-variable flexible grinding and polishing mechanism with the one-dimensional linear module force control servo motion platform. The one-dimensional linear module force control servo motion platform comprises a linear servo module motor, a ball screw, a linear module sliding block, a linear module base, and a controller. The invention further discloses a control method of the device. According to the full-digital rigid-flexible coupling precise force controlled grinding and polishing device, a one-dimensional force sensor collects a contact force signal of the speed-variable flexiblegrinding and polishing mechanism and a to-be-ground and polished workpiece and controls the servo motor to accurately move by the controller, so that the contact state between the speed-variable flexible grinding and polishing mechanism and the to-be-ground and polished workpiece is changed in real time, and the speed-variable flexible grinding and polishing mechanism and the to-be-ground and polished workpiece are maintained to be in flexible contact with self-adaptive variable force.

The invention relates to a shielding casing for a moving iron unit and assisted listening equipment using the shielding casing. The shielding casing for the moving iron unit comprises a casing body and a base, wherein a speaking terminal is arranged at the top of the casing body; the speaking terminal extends outwards to form a sounding tube; and the casing body is connected with the base. Compared with the prior art, the shielding casing disclosed by the invention has the characteristics that the casing body is formed by integrally stretching, so that the electromagnetic shielding performance of the casing body is greatly improved; no secondary processing is needed; and under the condition that the sound quality is kept unchanged, the manufacturing process is simple, the work strength is reduced, the production efficiency is increased and the production cost is reduced; magnetic mechanisms at the upper end and the lower end of an armature drive the armature to vertically vibrate; a vibrating diaphragm is driven by a vibration conducting rod to vibrate and sound from the sounding tube; the shielding casing can be directly arranged in ears and is simple and reasonable in structure, favorable in sounding effect and convenient in use; and the vibrating diaphragm is close to the speaking terminal and is positioned above the vibrating device and can be used for transmitting the vibration from the sounding tube through the speaking terminal so as to effectively ensure sounding quality.

The invention relates to a screening can and a telephone receiver of the screening can. The screening can comprises a bottom box and a box cover, wherein the box cover is arranged on the top of the bottom box, a step is arranged inside the bottom box and divide the bottom box into a bottom box front cavity and a bottom box rear cavity, and the step forms an angle A with the panel. According to the screening can, the step is aslant arranged in the bottom box, so that the size of the bottom box front cavity is reduced, the high frequency output of the telephone receiver is suppressed, dentals of the voice frequency is reduced, and sounds are improved. Through holes are formed in a vibrating diaphragm, so that the weight of the vibrating diaphragm of the telephone receiver is reduced, the high frequency output of the telephone receiver is improved, and the responsive bandwidth of the telephone receiver is increased. Holes capable of opening and closing are formed in a circuit board body, the structure is simple and reasonable, the low frequency output can be improved, and the output of voice is enriched. The telephone receiver is more convenient to use and meets the needs of people in daily life.

The invention relates to a photoelectric detector and a preparation method thereof. The photoelectric detector is of a transverse PN junction structure or a longitudinal PN junction structure, and comprises a semiconductor substrate provided with top-layer silicon, wherein a cone-shaped silicon waveguide is formed on the top silicon, the cone-shaped silicon waveguide is provided with a first end and a second end, and the area of the first end is smaller than that of the second end; the upper surface, close to the first end, of the silicon waveguide is covered with a first polycrystalline silicon layer; the upper surface, close to the second end, of the silicon waveguide is covered with a germanium layer, and the germanium layer and the first polycrystalline silicon layer are spliced together; wherein the P doped region and the N doped region are arranged in the top silicon layer and/or the germanium layer; and electrodes respectively formed on the upper surfaces of the P-doped region and the N-doped region. The coupling structure of the germanium-silicon photoelectric detector input waveguide active absorption region is optimized, high-efficiency coupling of the germanium-silicon photoelectric detector input waveguide active absorption region and the germanium-silicon photoelectric detector can be achieved, response is improved, and device power consumption is reduced.

The invention provides a full-closed-loop interference rate compensation self-stabilization control method under a geodetic coordinate system. The full-closed-loop interference rate compensation self-stabilization control method comprises the steps that a course angle, a pitch angle and a roll angle of an SINS are gathered, and a high-low angle and an azimuth angle of an artillery are gathered; angular velocity values of an SINS gyroscope group, a turret gyroscope group and a vehicle body gyroscope are gathered, interference angular rates in an azimuth direction and a high-low direction under the geodetic coordinate system are extracted, and filtering correction is performed to obtain azimuth and high-low compensation angular rate control quantities; the stable control rate control instruction and the interference compensation angular rate control instruction are combined to serve as a servo drive speed total instruction; and high-low and azimuth servo drivers gather respective motor angular rates, perform high-order sliding mode speed control strategy calculation according to the speed control instruction to obtain a current loop control instruction and drive motors to control artillery turning motions according to a given control quantity. The full-closed-loop interference rate compensation self-stabilization control method under the geodetic coordinate system has the advantages of being high in response bandwidth, accurate in interference rate compensation and the like, and the artillery barrel pointing high-precision stability under the condition of a movable base seat large firing angle is realized.