182results about How to "Amplitude adjustable" patented technology

Noise and interference can be independently measured in a multiple user Orthogonal Frequency Division Multiplexing (OFDM) system. Co-channel interference is measured in a frequency hopping, multiple user, OFDM system by tracking the sub-carriers assigned to all users in a particular service area or cell. The composite noise plus interference can be determined by measuring the amount of received power in a sub-carrier whenever it is not assigned to any user in the cell. A value is stored for each sub-carrier in the system and the value of noise plus interference can be a weighted average of the present value with previously stored values. The noise component can be independently determined in a synchronous system. In the synchronous system, all users in a system may periodically be prohibited from broadcasting over a sub-carrier and the received power in the sub-carrier measured during the period having no broadcasts.

The invention provides a display panel 9; a gain variable liquid crystal driving circuit 10 for driving the display panel 9 with an amplified video signal that is obtained by multiplying an input video signal by a variable coefficient; a backlight operating circuit 6 for operating, based on a lamp control signal, a backlight 8 for illuminating the display panel 9; a level extension signal calculating circuit 11 for outputting an optical output level extension signal Lout by extending a predetermined output level used to operate the backlight 8, wherein the predetermined output level is extended based on an optical output gain obtained from the input video signal, and an output peak value of the backlight 8; and a white peak improving circuit 5 for receiving the optical output level extension signal, and for outputting a lamp control signal, whose white peak level has been adjusted according to a change in brightness of a scene, to the backlight operating circuit 6, and for calculating and outputting a video amplitude gain, which adjusts an amplitude of a video signal, as a coefficient to a gain variable driving amplifier circuit 3, wherein the lamp control signal is outputted when the brightness of a scene is above normal level, and the video amplitude gain is outputted when the brightness is at normal level. As a result, there is provided a display apparatus that improves peak luminance in a bright scene and suppresses pale black display in a dark scene and thereby provide a wide dynamic range without increasing power consumption.

A quadrature amplitude modulation (QAM) signal generator, which can obtain optical signals such as QAM signals without handling multilevel electrical signals, can be produced by using a plurality of parallel Mach-Zehnder modulators (MZMs), such as quadruplex parallel MZMs (QPMZM). The quadrature amplitude modulation (QAM) signal generator includes a first waveguide, a first quadrature phase-shift-keying (QPSK) signal generator provided on the first waveguide, a second waveguide connected with the first waveguide at a wave-combining point, and a second quadrature phase-shift-keying (QPSK) signal generator provided on the second waveguide.

The invention relates to an electric energy quality harmonic disturbance source platform. In the disturbance source platform, an input circuit breaker cabinet, a disturbance source input switch cabinet, an output filter and switch cabinet and an output test cabinet are all connected to a 10kV bus; the disturbance source input switch cabinet, an input transformer and unit cabinet, the output filter and switch cabinet, a switch and output transformer cabinet and the output test cabinet are sequentially connected; the output test cabinet, the input transformer and unit cabinet are connected with the input control cabinet; the electric energy quality harmonic disturbance source outputs 0-50 times or stacking folds of standard harmonic voltage current source with adjustable amplitude and phase under the conditions of 10kV and 0.38kV fundamental voltages, and the maximal total harmonic distortion THDu is less than 20%. The platform can be used as a standard electric energy quality harmonic output source and a power grid equipment assessment platform for testing operation stability of a power grid and performance of power grid equipment under the harmonic output condition; electric energy quality problems about sag, fluctuation and three-phase imbalance of the power grid are simulated, and a platform is built for test, analysis and assessment of electric energy quality improvement.

The invention discloses a high-power pulse current / voltage generating circuit with programmable pulse width, duty ratio and pulse amplitude, wherein a digital-analog converter, an error amplifier, a power amplifier, a pulse current sampling circuit, a pulse voltage sampling circuit, a pulse current / voltage sampling selection switch and a peak detecting circuit are formed into a negative feedback loop. The amplitude analog signal output by the digital-analog converter is compared with the pulse peak obtained by the peak detecting circuit in the error amplifier; and the pulse peak is equal to the amplitude analog signal output by the digital-analog converter in the negative feedback loop. The power amplifier is connected with the output end of the comparator and is connected with the output end of the error amplifier through an input resistor; the comparator adjusts the frequency and duty ratio of the output high-power current / voltage under the control of the periodic pulse signal output by the pulse source, thus, the pulse width, the duty ratio and the pulse amplitude of the output pulse current / voltage of the high-power pulse current / voltage generating circuit can be adjusted.

A piezoelectric oscillation circuit includes: a DC power supply; a stabilized power supply that stabilizes a voltage variation in a DC voltage supplied from the DC power supply; an oscillation circuit unit that uses a piezoelectric vibrator as a vibratory source; a buffer circuit unit to which an output signal output from the oscillation circuit unit is input, a plurality of stages of inverter circuits are connected in series, and a depletion type MOS transistor is connected to the last stage inverter circuit; an output amplification circuit that amplifies an output of the buffer circuit; an output level adjustment circuit that includes a plurality of MOS switches and resistive elements and adjusts an output level by varying a gate voltage of an Nch-transistor included in the output amplification circuit; a memory circuit that stores data for selecting one of the plurality of MOS switches; and a decoder that generates an analog signal to be input to the MOS switch on the basis of the data stored in the memory circuit.

The invention relates to a tunable flat absorbing material for electromagnetic waves and belongs to the technical field of electromagnetic functional material. The tunable flat absorbing material comprises a metal reflecting layer, a dielectric layer, a vanadium oxide phase-change material layer and a metamaterial layer; the dielectric layer is located between the metal reflecting layer and the vanadium oxide phase-change material layer; and the vanadium oxide phase-change material layer is located between the dielectric layer and the metamaterial layer. In the invention, a vanadium oxide phase-change film is inserted between the metamaterial layer and the dielectric layer of the three-layered electromagnetic wave absorbing material and used for controlling the absorption efficiency and the absorption frequency of the electromagnetic wave absorbing material by using the heat, electricity or light triggered phase-changing courses. The tunable flat absorbing material disclosed by the invention has simple structure and easiness in preparation and has the features of tuning absorption amplitude and absorption frequency, and the modulation depth of more than 70% can be achieved; the modulation manners are various and the modulation for absorbing terahertz wave can be realized by means of many manners such as heat or electricity or laser and the like; and the tunable flat absorbing material is applicable to electromagnetic protection, invisible technology, spectrum detection and thermal radiation and the like of the microwaves, terahertz waves and optical waves.

The invention relates to a chaotic signal source with adjustable dynamic amplitude linearity and a system with identical dynamic characteristics, comprising an inverse proportion circuit, a first integrating circuit, a second integrating circuit and a third integrating circuit, wherein the output ends of a third operational amplifier, a second operational amplifier and a first operational amplifier sequentially output three state variables (x, y, z) of the chaotic signal source; when the chaotic signal source works, the dynamic amplitudes of the three state variables (x, y, z) are linearly adjusted by adjusting the output voltage of a DC power supply, and the three state variables (x, y, z) are enabled to have the identical dynamic characteristics. Because the chaotic signal source has adjustable amplitude and frequency spectrums of different frequency ranges and the like under the precondition without changing the dynamic characteristics of an output signal, the chaotic signal source is indicated to have extensive application prospect and important application value in the high technology fields of chaotic radars, secret communication, electronic countermeasure, and the like.

The present invention is directed toward a method for setting a driving voltage of a differential quadrature phase-shift modulator, this method making signal quality superior in response to an individual difference in extinction ratio due to variations in manufacture of a device. To this end, signal quality of differential quadrature phase-shift modulated light output from a differential quadrature phase-shift modulator is acquired. An average amplitude of a first or second driving voltage signal is adjusted according to the signal quality of the thus-acquired differential quadrature phase-shift modulated light.

A highly reliable semiconductor device in which a shift in threshold voltage of a transistor due to deterioration can be inhibited is provided. A pulse output circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor. A clock signal is supplied to a drain of the first transistor. A first power supply potential is applied to a source of the second transistor, and a drain of the second transistor is connected to the drain of the first transistor. A second power supply potential is applied to a drain of the third transistor. The first power supply potential is applied to a source of the fourth transistor, and a drain of the fourth transistor is connected to the drain of the third transistor. The first power supply potential is applied to a source of the fifth transistor, and a drain of the fifth transistor is connected to a gate of the third transistor. One of a source and a drain of the sixth transistor is connected to the drain of the first transistor, and the other of the source and the drain of the sixth transistor is connected to the gate of the third transistor. The first transistor and the third transistor include back gates connected to each other. The first to sixth transistors have the same conductivity type.

The invention discloses a vibration movement device for a main shaft of a numerical control electrochemical machining machine tool, and belongs to the field of electrochemical machining. The vibration movement device comprises a space cam, a cam guide sleeve, a guide shell and a vibration device. The space cam comprises a transmission input shaft and a guide groove, wherein the transmission input shaft is connected with the main shaft of the numerical control electrochemical machining machine tool, and the guide groove is a symmetrical sine wave groove. The cam guide sleeve is internally provided with a sliding cam pin protruding inwards, and is located in the guide groove of the space cam after being installed, and a guide rail is arranged on the outer side of the cam guide sleeve. Linear guide grooves which are symmetrically distributed are formed in the guide shell, and the guide rail of the cam guide sleeve is located in the linear guide grooves after the guide shell is installed. The vibration movement device for the main shaft of the numerical control electrochemical machining machine tool is simple in structure, the cost of the vibration movement device can be reduced easily, large loads, frequency and amplitude can be adjusted, electrolyte can be sprayed to a machining area from the interior of a cathode, discharging of electrolysate produced in electrochemical machining can be effectively improved, and the precision of the numerical control electrochemical machining can be improved.

A conveyor system and a method for driving a conveyor are disclosed. In the method, electric power is supplied to the drive machinery of a conveyor depending on the power requirement with a supply device to be selected from at least two different adjustable supply devices, and the supply device supplying power to the drive machinery is changed on the basis of the power requirement of the conveyor.

Disclosed is a hydrocarbon catalytic cracking method for maximizing gasoline. According to the method, on a catalytic cracking condition, hydrocarbon oil and a cracking catalyst are allowed to contactwith each other, diesel oil is injected to the position at the middle of a riser reactor to perform catalytic cracking reaction to obtain products such as liquefied gas, gasoline, diesel oil and heavy oil. The catalyst comprises modified molecular sieves, clay and pseudo-boehmite. A preparation method of the catalyst includes subjecting pseudo-boehmite to acid dissolution and then mixing the samewith other components of the catalyst to form slurry, adding alkaline substance in the slurry to keep pH value of the slurry within the range of 3.3-5.0, and then carrying out spray drying, solidifying and washing to obtain the catalyst. The catalytic cracking catalyst has adjustable volume, has excellent activity stability, cracking reaction selectivity and heavy-metal contamination resistance capacity. The hydrocarbon catalytic cracking method has the effect of increasing yield of gasoline obviously.

A method and a system for operating bits of memory cells in a memory array, the method including applying a first operating pulse to a terminal of a first cell, the first operating pulse is intended to place the first cell into a predefined state; and applying a second operating pulse to a terminal of a second cell in the set, the second operating pulse is intended to place the second cell to the predefined state, and the pulse characteristics of the second operating pulse are a function of the response of the first cell to the first operating pulse.

The invention provides a method of correcting an initial position of a rotor of a permanent magnet synchronous motor. The rotor is shaken at high frequency through applying a current vector of a positive and negative pulse, the deviation size of the initial position of the rotor can be judged through the size of shaking degree, and a deviation value can be gradually reduced through changing a direction of the current vector. Through the action of the positive and negative pulse, the rotor is prevented from moving towards one direction at overlarge range or for overlong time, so that the movement of the rotor when the next current vector is acted cannot be affected, and the problem of mistakes in judgment is avoided. The amplitude of the current vector and the action time of the positive and negative pulse can be adjusted, the frequency and the amplitude of rotor vibration are enabled to be adjustable, and the flexibility and the disturbance rejection of a detection process are enhanced.

The invention relates to a harmonic impedance measurement apparatus of an electric power system. A transformer T is connected with a public electric network P; the harmonic impedance measurement apparatus NHID is connected to an A phase, a B phase and a C phase of a low-voltage side of the transformer T. The NHID is composed of a harmonic injector ID, a control unit CD, a power source unit SU and a measurement calculation unit MCM; the harmonic injector ID includes a direct-current energy storage capacitor C, large-power electronic power switches from S1 to S6, and a three-phase boosting transformer Ts1. And the whole injection process is completely controllable. According to the invention, precise measurement and calculation can be carried out to obtain the harmonic impedance of the system and reliable harmonic impedance parameters can be provided for harmonic treatment.

A total amplitude supporting high-frequency linear vibrating screen belongs to the field of vibrating screening machinery and mainly solves the problem that the existing high-frequency vibrating screen is insufficient in vibration frequency and can not meet production requirements. A plurality of sections of screen cloth are arranged on a screen cloth bracket transversely in a tightening mode in an arc shape, two vibrating devices or vibrating motors are arranged on horizontal and vertical vibrating device base plates in the middle of a vibrating beam, and a vibrating resultant action line passes through the gravity center of a screen box. The screen box is connected with a total amplitude elastic supporting base on a base support through four square trunnions. The total amplitude elastic supporting base is composed of an upper support, a lower support and rubber springs, and the square trunnions are arranged between an upper rubber spring and a lower rubber spring. The base support is connected with a base through a secondary damping device. A sealed slurry material box is arranged at the feeding end of the screen box on the base support. The total amplitude supporting high-frequency linear vibrating screen has the advantages of being high in vibrating frequency and large in vibrating strength and material screening productivity and the like, can be widely applied to precise screening of milled powder of an iron mine ball mill, fine-mesh-level wet materials like petroleum drilling slurry, coal and chemical-mesh-level materials.

The invention discloses a water-hammer type pressure pulse generating nipple comprising an external structure and an internal structure, wherein the external structure comprises an outer cylinder, an upper joint and a lower joint; and the internal structure comprises a flow guiding body, a valve wheel subassembly, a normally-open flow passage, a nozzle and two valve-control flow passages, wherein the flow guiding body is arranged at the upper end of the valve wheel subassembly, the valve wheel subassembly is arranged at the upper ends of the normally-open flow passage and the valve-control flow passages, the valve-control flow passages are periodically opened and closed through the valve wheel subassembly and are connected with the normally-open flow passage in parallel, and the nozzle is arranged at the lower end of the normally-open flow passage. In the invention, the valve-control flow passages are opened and closed by periodically rotating the valve wheels to generate water-hammer type pressure pulses.

An electromagnetic rocking chair comprises a base, a chair seat, two fixed rods, and two suspension rods. Each of the fixed rods has a lower end fixed on one end of the base, and a transverse shaft is fixed on both upper ends of the fixed rods. An upper end of the respective suspension rods is pivotally connected to the transverse shaft, and the chair seat is disposed between the two suspension rods. A permanent magnet is disposed at the lower end of one of the suspension rods, and under the permanent magnet are disposed two electromagnets fixed on the base. On the base are further fixed two displacement sensors. The two electromagnets and two displacement sensors are connected to a control circuit on a circuit board. The electromagnetic rocking chair has advantages of simple and reasonable structure design, stable running, no noise, adjusting rocking amplitude and the like.

A triangular wave generator, comprising: a first frequency divider, for utilizing a first positive integer to divide a first frequency of a first periodical signal to generate a first frequency-divided signal; a second frequency divider, for utilizing a second positive integer to divide a second frequency, which equals the first frequency multiplying a third positive integer, of a second periodical signal to generate a second frequency-divided signal; and an up / down counter, for generating a triangular wave first and second frequency-divided frequencies respectively belonging to first and second frequency divided signals; wherein a frequency of the triangular wave equals to the first frequency-divided frequency, and an amplitude of the triangular wave is determined according to a ratio of the first and second frequency-divided frequencies.

Noise and interference can be independently measured in a multiple user Orthogonal Frequency Division Multiplexing (OFDM) system. Co-channel interference is measured in a frequency hopping, multiple user, OFDM system by tracking the sub-carriers assigned to all users in a particular service area or cell. The composite noise plus interference can be determined by measuring the amount of received power in a sub-carrier whenever it is not assigned to any user in the cell. A value is stored for each sub-carrier in the system and the value of noise plus interference can be a weighted average of the present value with previously stored values. The noise component can be independently determined in a synchronous system. In the synchronous system, all users in a system may periodically be prohibited from broadcasting over a sub-carrier and the received power in the sub-carrier measured during the period having no broadcasts.

The invention discloses a micro-nano scale wave structure in a macroscopic composite material and a preparation method thereof, and belongs to the technical field of functional composite materials. Atwo-dimensional nano-material dispersion solution is self-assembled to form a macroscopic structure including a thin film, gel and the like; a carbon-nitrogen compound is generated by utilizing thermal chemical reaction and the state of a two-dimensional composite material is regulated and controlled to form the micro-nano scale wave structure. The micro-nano scale wave structure disclosed by theinvention has the characteristics that a preparation technology is simple, the size and shape of the composite material are easy to regulate and control, the mechanical elasticity, an electronic structure or a surface state of the material is adjustable and the like; a foundation is laid for researches and application of an assembled macroscopic material to the fields including flexible conductors, micromechanical electronics and flexible energy storage devices, catalytic carriers and the like.

The invention provides a power distribution network singlephase earth fault positioning method and system based on frequency sweep injection; the system comprises a plurality of to-be-positioned lines; input ends of the plurality of to-be-positioned lines are respectively connected with output ends of a three-phase bus; the output ends of the plurality of to-be-positioned lines are respectively electrically connected in order with a three-phase voltage transformer and three high voltage switches; the system also comprises a controllable power supply respectively electrically connected with thethree high voltage switches, and a plurality of fault indicators respectively scattered on the plurality of to-be-positioned lines and respectively located behind the three high voltage switches; thecontrollable power supply can inject the current with a wide frequency and an adjustable amplitude into the three-phase bus; the injection process employs a frequency sweep method; the injection current can be set according to different power grid framework parameters; the current with the optimal injection characteristics is selected; aiming at the current with the optimal injection characteristics, the real time characteristic current value in each phase of the three-phase bus can be returned by the fault indicators, thus determining a fault area. Compared with the existing positioning mode, the power distribution network singlephase earth fault positioning method and system are higher in accuracy.

The invention discloses a long-time voltage tolerance test device for a direct-current transfer switch lightning arrester. The device comprises a direct-current power supply, a high-voltage switch, acapacitor, a damping resistor, a reactor and a test sample, wherein the direct-current power supply is connected with the high-voltage switch; the output end of the direct-current power supply is connected with the capacitor, the input end of the direct-current power supply is connected to a power frequency power supply, and the capacitor, the high-voltage switch, the damping resistor, the reactorand the test sample are sequentially connected in series to generate low-frequency resonance to form a series loop. According to the device and method, series resonance is generated through a loop consisting of the capacitor, the damping resistor and the reactor, square wave voltage with adjustable amplitude and controllable duration is generated on the test sample, an overvoltage working condition borne by a lightning arrester in the direct current conversion process is restored, the long-duration voltage tolerance characteristic of the lightning arrester is obtained, the fault of the lightning arrester caused by the fact that the voltage tolerance characteristic is not satisfied is avoided, the direct current conversion switch lightning arrester is effectively checked, and the long-timevoltage tolerance test device has the advantages of long voltage duration and adjustable voltage amplitude and duration.

A signal processing circuit for adjusting an input signal and generating a corresponding digital output signal in an optical disk driver is provided. The signal processing circuit includes an attenuator for receiving and attenuating the input signal and then generating an attenuated output signal; a gain controllable amplifier for receiving and amplifying the input signal and then generating an amplified output signal; a control unit providing a control signal and a select signal, the control signal is directed to the attenuator and the gain controllable amplifier for enabling / disabling the attenuator and the gain controllable amplifier and for controlling their gains such that one of the attenuator and gain controllable amplifier is enabled at a time; and a waveform adjuster circuit for adjusting the amplified / attenuated output signal delivered from the gain controllable amplifier or the attenuator so as to generate the digital signal related to the input signal.

The invention relates to a pulse signal generator comprising a DC high voltage source, a voltage display unit, a coaxial current-limiting unit, a TLP circuit, a pulse control unit, a drive amplification unit and a frequency counting and display unit. The DC high voltage source is used for converting alternating current commercial power into continuously adjustable direct current. The coaxial current-limiting unit is used for controlling size of charging current of the TLP circuit which is used for generating a nanosecond-level high current pulse signal. A frequency signal outputted by the pulse control unit is amplified by the drive amplification unit and then controls a working mode of the TLP circuit. The frequency counting and display unit counts and displays the frequency signal generated by the pulse control unit. A situation that existing pulse signal generators cannot output pulse signals which are rapid in rising period of time and short in action time is solved by the pulse signal generator. The pulse signal generator is the device capable of generating the pulse signal which is rapid in rising period of time, short in action time and wide in amplitude dynamic range so that a requirement of anti-interference performance assessment of an electronic device can be met.

The invention discloses plastic vibration processing and sample molding integration test equipment and a method. The equipment comprises a hydraulic power system, a vibration power driving system, a test platform, a piston assembly, a central mould, a visualization device, a controlling system and the like. The equipment and the method combine vibration field quantity with mould sample molding, combine cutting, pressing, vibration and sample processing molding function into a whole, are different from rheological property research limited by polymer of a traditional rheometer, avoid form change of plastic mixture structures when materials in a test cavity are taken out, monitor a microstructure online directly or directly mold and obtain detecting samples. The plastic vibration processing and sample molding integration test equipment and the method can not only achieve the rheological property test of moving state and steady state of the polymer, but also be used for microstructure form research of a plurality of polymer systems under multi-element field quantity and influence rule research between processing performance and technological conditions. The plastic vibration processing and sample molding integration test equipment and the method can be widely applied to industries of material, chemistry, pharmacy, coating, food, building and the like.