105 results about "Pulse front" patented technology

This invention relates to a measuring method and device of impulse form. The invention includes one constant proportion timing discriminate module and one time-to-digital conversion module. Data of time-to-digital conversion modular enter calculator for handling. Constant proportion timing discriminate module has a group of leading edge discriminator and a group of back edge discriminator, which separately discriminate a series of points where the ratio of pulse front edge and back edge voltage and spike voltage are certain worth corresponding time. multipass time-to-digital conversion module convert time interval between first time and subsequently time to digital quantity, adopt digital counting method and combine digital delay line bracketing method, realize at a piece of field programmable logic array FPGA. sending obtained data into computer for calculation to gain time interval, base on voltage peak ratio of every time to indirectly reduce impulse form, and obtain pulsewidth. The invention has low cost, small bulk, and light weight, can apply to laser range finder.

A terahertz wave generator includes a femtosecond pulse light source 1 that outputs a near-infrared light L₁, which is a pulse light, a diffraction grating 2 that diffracts the outputted near-infrared light L₁, an optical system including a lens 3 and a lens 5, and a LiNbO₃ crystal 6 for generating terahertz waves L₂ with irradiation of the near-infrared light L₁. The optical system including the lens 3 and the lens 5 is arranged such that at least a pan of a plane S₀′ optically conjugated to a diffractive plane S₀ of the diffraction grating 2 is formed within the LiNbO₃ crystal 6, and a direction normal to the conjugated plane and a direction normal to a plane formed by the pulse front of the non-linear L₁ are matched with each other within the LiNbO₃ crystal 6. This makes it possible for the near-infrared light L₁ to cause the nonlinear optical effect to efficiently occur in the wide range, whereby high-efficient and high-power terahertz waves can be obtained.

The invention discloses a time-of-flight mass spectrometer electronics reading method which can improve time resolution and a quantitative performance of a time-of-flight mass spectrometer at the same time and is different from an electronics reading scheme of a traditional time-of-flight mass spectrometer by an ADC (Analog to Digital Converter) waveform sampling or a TDC (Time to Digital Converter) pulse time measuring. The pulse front edge time measurement and a pulse forming sampling scheme are combined; the front edge time measured by the TDC is corrected by amplitude information obtained by a middle and low speed ADC for sampling a formed pulse, so that a time resolution effect is obviously improved, and the quantitative performance of an apparatus is improved. According to the reading method, an expensive high-speed ADC (over 1G SPS (samples per second) ) chip is replaced by a pulse forming circuit and the middle and low-speed ADC (about 100M of SPS); a constant fraction discriminator (CFD) circuit in a traditional time-of-flight mass spectrometer reading electronics is replaced by utilizing direct pulse front edge screening, and apparatus cost is reduced when a performance is improved.

A method and an electron source are provided for generating polarized electrons for an electron microscope. The electron source includes a photoemissive cathode and a low-power drive laser. The geometry of the photoemissive cathode uses a generally planar emission surface, which is imaged to approximately 1/100 its initial size via electrostatic focusing elements. The virtual emitter, or image spot, then is used as an electron source by a conventional microscope column.

The invention provides a dynamic balance test method and a device thereof. The dynamic balance test method is used for testing workpieces with peripheries distributed with grooves uniformly and includes steps as follows: axially rotating a workpiece; utilizing a non-contact sensor to test the grooves on the workpiece at a fixed position and generate a pulse signal, wherein the pulse signal generated by the non-contact sensor when the workpiece begins to rotate is used as an unbalance datum zero-degree signal; dividing frequency of the pulse signal, wherein multiple of frequency dividing is equal to the amount of the grooves on the workpiece; and defining unbalance amount and unbalance angle according to the pulse signal after frequency dividing, wherein a first pulse front edge of the unbalance datum zero-degree signal is used as a zero-angle position of the workpiece when defining the unbalance angle. The dynamic balance test method and the device thereof remove special processes on the surface of the workpiece and save working procedures, thereby increasing positioning accuracy of unbalance angle tests. The dynamic balance test method and the device thereof are adoptable to automation of dynamic balance.

The invention discloses a generating device of a large-amplitude ultra-high speed synchronization pulse. The generating device of the large-amplitude ultra-high speed synchronization pulse comprises an input signal shaping circuit and a synchronization pulse generating circuit, wherein the input signal shaping circuit is used for shaping input trigger pulse signal to output low voltage positive pole emitter coupling logic (LVPECL) reference level signal, and the synchronization pulse generating circuit is used for generating the large-amplitude ultra-high speed synchronization pulse with the LVPECL reference level signal as trigger signal. No transistor with an extremely high working voltage is needed in the generating device and method of a large-amplitude ultra-high speed synchronization pulse, therefore, voltage demand on a direct current voltage source is not high. Key functions of the generating device and method of a large-amplitude ultra-high speed synchronization pulse is achieved by a multilevel broadband transistor circuit which can send out positive pulse and negative pulse with pulse front smaller than 200ps and amplitude close to 15V. Meanwhile, compared with input synchronization pulse, delaying time shake of output synchronization pulse is small and smaller than 20ps.

A recording method for dye-based recordable DVD medium which includes recording shortest marks on a recording layer primarily containing an organic dye using a simple rectangular wave pulse; recording marks each having the second shortest or still longer mark length using one pulse of which the front and rear edges are highly energized for a given time; and controlling the optical energy for irradiating rear edge or backward of the pulse with a cooling pulse to be 0.1 mW or less for a given time, wherein when the recording power of the front and rear edges of the respective pulses is represented by P₁ and the recording power of intermediate pulse between the pulse front edge and the pulse rear edge is represented by P₂, P₁/P₂ is set to be greater when P₁ is a low power, and P₁/P₂ is set to be smaller when P₁ is a high power.

The invention discloses a measuring device and measuring method for large diameter ultrashort laser pulse front edge radial group delay. The device comprises a Michelson's interferometer and a second order auto-correlator which are arranged at a pulse output end; an oscilloscope, a near field diaphragm and a far field light path which is used for correcting combined beam light path. By use of the device and method, the size of optical elements required by a measuring device is greatly decreased; no extra ideal reference light is required to be introduced or no extra optical element is required to be introduced to produce ideal reference light; direct measurement of front edge radial group delay of large diameter ultrashort laser pulse output by a laser system of high peak power is achieved for the first time; the device and method are convenient to adjust, easy and efficient and have high practicality.

The present invention discloses a high-efficiency and double-exponential electromagnetic pulse generation device, and relates to the field of the circuit technology for generating electrical pulses. The pulse generation device comprises a direct current source, a triggering circuit and a Marx circuit; and the output end of the direct current source is connected with the triggering circuit and the power supply input end of the Marx circuit, the output end of the triggering circuit is connected with the signal input end of the Marx circuit through an optocoupler, and the output end of the Marx circuit is the pulse signal output end of the pulse generation device. The pulse generation device is able to output selective voltage peak values, pulse width and pulse front, is small in size, high in stability, high in efficiency, high in repetition frequency and convenient for usage.

The invention discloses a compensation device and method for pulse-front distortion in a femtosecond laser pulse amplification system. The device is arranged between two amplification stages of the femtosecond laser pulse amplification system. The device comprises a concave lens and an off-axis parabolic mirror, wherein a focal length of the off-axis parabolic mirror is greater than the focal length of the concave lens; and the off-axis parabolic mirror and the concave lens are arranged in confocal way. The focal length of the concave lens is determined through calculation of the pulse-front distortion introduced by all lens beam expanders in the femtosecond laser pulse amplification system. The focal length of the off-axis parabolic mirror can be determined according to a beam expanding ratio required by the femtosecond laser pulse amplification system and the focal length of the concave lens. Through use of the device in the femtosecond laser pulse amplification system, beam expansion of laser pulses can be realized, and the pulse-front distortion caused by the lens beam expanders can be effectively compensated, so that real focusing peak intensities of focused femtosecond laser pulses are improved.

The invention provides a high-speed DA-based multi-channel signal high-precision synchronous control method and device, and solves the technical problem that an existing technology cannot realize high-precision control on multi-channel signals under the condition of ensuring the phase consistency. The method comprises the following steps of 1, generating a calibration signal; 2, measuring a time difference between channels: testing a time advance of a pulse front edge on each channel relative to a pulse front edge of the latest channel to obtain a delay quantity needed by each channel; 3, calculating a calibration value: multiplying the delay quantity by a sampling frequency of DA and performing rounding to obtain the calibration value of each channel; 4, performing synchronous fine adjustment and calibration: performing time delay of the corresponding calibration value on a signal generation unit by a fine adjustment and calibration module in an FPGA; and 5, generating the multi-channel signals synchronously. The control method and device is widely applied to the field of multi-radiation signal source signal synchronization.

A high-frequency and high-voltage pulse generator for sterilization relates to a pulse generator. A control circuit and a pulse generating circuit are provided; the control circuit is provided with a voltage comparator, a triode, a first NAND gate, a second NAND gate, a coupler, and a relay; the pulse generating circuit is provided with a relay normally open switch, MOSFET switching tube, first transformer, second transformer, diode, capacitor, spark arrestor. Based on the traditional high-frequency pulse device, a timer based on NE555 is designed, and DSP is used to digitally process the sterilization signal, so that the interference of the sterilization circuit is greatly reduced. Capacitor charging and discharging is used to obtain high-voltage pulses, so that the output pulse can reach 12-100kV/cm, and the width is controlled at the microsecond level, and the pulse front is controlled at the nanosecond level, which can effectively sterilize and will not change the food composition. ; It can be turned on and off in an instant and has a large flow capacity and reliable operation.

The invention discloses a flue gas desulfurization and denitrification method for generating a pulsed power supply based on nanosecond-grade plasma. The method comprises the following steps: (S1) primary dust removal, (S2) humidifying cooling, (S3) reactor treatment, (S4) secondary dust removal and (S5) discharging. The flue gas desulfurization and denitrification method for generating the pulsedpower supply based on the nanosecond-grade plasma is strictly controlled, a pulsed power supply is generated by virtue of the nanosecond-grade plasma, a circuit is adopts a high-power pulse and magnetic compression techniques, a three-phase rectifying circuit generates a direct current bus voltage, and a microsecond-grade low-voltage pulse is generated by a pulse generating device, is boosted to be a high-voltage pulse by a pulse booster and is compressed into a nanosecond-grade high-voltage pulse by a pulse compression device, so that the aims of steepening a pulse front edge, narrowing a pulse width and improving the repetition frequency are achieved, and then the ultralow environment-friendly requirements on desulfurization, denitrification and dust removal are realized; and compared with power supplies in other forms, the method has the advantages that the energy consumption is reduced, the utilization rate of electric energy is increased, and the generation efficiency of the plasma is improved.

The invention relates to a multi-radar countermeasure method and system. The method comprises the steps of carrying out the frequency division of a received radar radio frequency signal, obtaining a frequency division intermediate frequency signal after the frequency division of the received radar radio frequency signal and a frequency division local oscillator signal, carrying out the frequency detection of the pulse front edge of the frequency division intermediate frequency signal, and obtaining a pulse starting frequency; performing broadband and narrowband judgment on the frequency division intermediate frequency signal of the radar signal to obtain a broadband and narrowband judgment result of the broadband signal or the narrowband signal; calculating the center frequency of the broadband signal for the broadband signal according to the broadband and narrowband judgment result; determining a local oscillation signal frequency range of the narrow-band signal according to the pulsestarting frequency and switching to the corresponding local oscillation signal according to the broadband and narrowband judgment result; for the broadband signal, determining the frequency range ofa local oscillation signal according to the center frequency of the broadband signal and switching to the corresponding local oscillation signal; and mixing the local oscillator signal and the radar radio frequency signal to generate an intermediate frequency radar signal, and generating a radar interference signal according to the intermediate frequency radar signal.

The invention discloses a cascaded double-exponential nuclear pulse signal generating device and a control method thereof. The cascaded double-exponential nuclear pulse signal generating device can becompatible with nuclear pulse signals output by different types of detectors. The device takes a CPU, an FPGA and a high-speed digital-to-analog conversion chip as cores, and comprises a current-to-voltage conversion module, a baseline bias adjustment module, a signal amplitude adjustment module, a high-frequency filter network and an output drive enhancement module. The control method of the device comprises the steps that a CPU receives relevant parameters from a PC or a handheld terminal, cascaded double-exponential nuclear pulse signals are generated according to an algorithm formula, anFPGA controls a high-speed digital-to-analog conversion chip DAC to generate double-exponential nuclear pulse signals with different pulse amplitudes and widths, the pulse leading edge integral time constant and the trailing edge differential time constant are adjustable, and a single or periodic nuclear pulse signal may be generated. The device is especially suitable for nuclear radiation signalmeasurement, test, calibration, calibration and the like under the condition of no actual radionuclide source.

The invention relates to a digital intelligent cicerone apparatus and the method for realizing this. The apparatus comprises: vehicle mount receiving controller 1, display controller 2, node display 3, speech storage 4 and node storage 5; wherein the vehicle mount receiver 1 gets moving data of vehicle in standard range in total driving excursion; the total driving excursion is in the trigger range which takes the distance from the right boundary point of the unit standard range to the right boundary point of the relevance range; the relevance number of each relevance range that matches with vehicle moving data are displayed by control flag driving code of pulse front edge or rear edge which is generated on opening/closing vehicle door, and matches with telling station name with in speech.

The invention discloses a method improving radar active beacon machine precision; the method comprises the following steps: using a logarithm detection mode to process and receive an inquiry signal; shaping the signal and outputting a pulse signal to serve as a reference signal for a DRFM; reducing radar emitting and receiving power changes caused by the temperature and weather change factors, thus obviously improving alignment calibration precision. The method uses the logarithm demodulation mode to process and receive the inquiry signal, can effectively reduce radar emitting and receiving power changes caused by the temperature and weather change factors, and can prevent shaking phenomenon of pulse front edge after demodulation, thus obviously improving alignment calibration precision, and a distance precision can reach precision requirements needed by a fire control radar for alignment calibration.