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106results about How to "Improve modulation effect" patented technology

Wireless terminal transceiver of 60GHz RoF (Radio over Fiber) access system

The invention discloses a wireless terminal transceiver of a 60GHz RoF (Radio over Fiber) access system. Secondary subharmonic frequency mixing is adopted, and the frequency of a needed local oscillation signal is reduced in a frequency multiplication frequency mixing way, so that the problem of leakage of the local oscillation signal to an antenna, i.e., a radiofrequency transmitting end in the conventional wireless terminal transceiver scheme is solved, and the circuit modulation performance is improved. Meanwhile, a downlink medium frequency analog signal obtained after secondary subharmonic down-conversion is subjected to downlink medium frequency digital signal processing after ADC (Analog to Digital Conversion) to obtain a needed downlink digital baseband signal; and an uplink digital baseband signal is subjected to uplink medium frequency digital signal processing to obtain an uplink medium frequency digital signal. A series of medium frequency digital signal processing such as odd-even extraction or interpolation, symbol modulation, delay filtering, demodulation or modulation and the like is performed in a digital domain, so that the problem of IQ orthogonal mismatch caused by 90-degree phase change on a local oscillation signal for obtaining two paths of analog signals in an analog frequency domain of the conventional receiver is solved.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Tunable nanometer antenna and preparation method thereof

The invention provides a tunable nanometer antenna and a preparation method thereof. The tunable nanometer antenna comprises three layers which comprise an upper layer metal structure, a middle layer single-layer grapheme and bottom substrate materials; the upper layer metal structure is a bowknot structure; the bowknot structure is formed by two isosceles trapezoids and a square. The preparation method of the tunable nanometer antenna comprises the following steps of covering the layer of single-layer grapheme on a silicon dioxide substrate through a chemical vapor deposition method; coating resist coating in a rotary mode on the single-layer grapheme; achieving structural corrosion and developing through the electron beam lithography technology; achieving evaporation of a golden layer through the vacuum electron beam evaporation technology; obtaining a final nanometer optical antenna through a lift-off process. The tunable nanometer antenna has the advantages of being small in size due to the fact that the thickness of a metamaterial structure is in the dozens of nanometer level and beneficial to application in integration optics; being high in signal intensity due to the fact that magnetic field enhance through the nanometer optical antenna can achieve more than 20000 times under illumination of incident light under specific frequency; being obvious in modulation effect.
Owner:HARBIN INST OF TECH SHENZHEN GRADUATE SCHOOL

Online projection objective wave aberration detection device and method

The invention relates to an online projection objective wave aberration detection device and method. The detection device comprises a light source, a rotary scatterer, a first focusing lens, an optical fiber array, a second focusing lens, a scattering optical element, an object plane optical grating, an image plane optical grating, a two-dimensional photoelectric sensor, a phase-shift control module and a computer, wherein the rotary scatterer is composed of a support, an electric motor and a circular diffusion scattering optical element, and is combined with the multimode optical fiber array for converting a coherent light or partially coherent light source into incoherent light; ten interference fringe patterns with phase shifting amounts of 0, pi/6, pi/3, pi/2, 2pi/3, 5pi/6, pi, 5pi/3, 3pi/2 and 11pi/6 respectively are acquired to calculate a phase position and the influence of multilevel diffraction light interference of the optical grating on the phase position extraction precision is eliminated. The device and the method can improve the modulation effect of the object plane optical grating on the optical field spatial coherence so as to achieve a high-precision alignment effect, reduce the system error of phase position extraction in wave aberration detection and improve the wave aberration detection precision of an optical system.
Owner:SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI

Optical transceiver module with double arms of modulator capable of achieving modulation independently

The invention discloses an optical transceiver module with double arms of a modulator capable of achieving modulation independently. The optical transceiver module comprises a laser device, a laser device drive circuit, a transmitting-end optical assembly, a receiving-end optical assembly, a modulator drive circuit, a receiver circuit and a microprocessor, wherein the transmitting-end optical assembly comprises a Mach-Zehnder modulator, the modulator drive circuit comprises a first-stage amplifier and two second-stage amplifiers connected to the output end of the first-stage amplifier in parallel, the output ends of the two second-stage amplifiers are connected with the Mach-Zehnder modulator respectively, and different modulation voltages of two drive sub-circuits are controlled through the microprocessor. In this way, different modulation depths of the left and right arms of the Mach-Zehnder modulator are achieved, longer-distance transmission is achieved, and optical transmission cost is greatly reduced; besides, because the modulator drive circuit is in communication with the microprocessor, only an internal drive circuit and I2C communication between the microprocessor and the drive circuit rather than input and output of a client are needed to be additionally designed, and the optical transceiver module has good compatibility.
Owner:SHAOXING ZKTEL EQUIP

Spectrum broadening method and device based on digital micromirror device (DMD)

The invention belongs to the field of astronomical optical observation, and particularly relates to a spectrum broadening method and a spectrum broadening device based on a digital micromirror device(DMD). The spectrum broadening method comprises the steps of: firstly, subjecting a target spectrum to chromatic dispersion to a row or column direction of the digital micromirror array DMD, wherein the row or column direction of the DMD is consistent with a row or column direction of a detector; secondly, segmenting the spectrum subjected to chromatic dispersion along row pixels or column pixelsof the detector according to different spectral bands by means of the digital micromirror device DMD and reflecting the segmented spectral bands to different positions on the same plane, so as to realize spectrum broadening; thirdly, compressing and collimating the segmented different spectral bands to enter into an interference module to obtain interference fringes; and finally, performing secondary chromatic dispersion on the interference fringes in the row or column direction of the detector to realize high-precision light splitting, so as to obtain high-resolution spectral interference fringes. The spectrum broadening method and the spectrum broadening device realize the spectrum broadening of the detection system while avoiding the problems of fringe bending, contrast reduction and the like caused by cross chromatic dispersion, and solves the problem that reflected surfaces are not on the same image plane during spectral narrow band segmentation under the condition of multi-targetdetection by adopting an image segmentation device broadening method.
Owner:XI'AN INST OF OPTICS & FINE MECHANICS - CHINESE ACAD OF SCI

Stable laser light source

The invention discloses a stable laser light source. Given optical power and fed-back optical power are added by an adder, and then the added optical power enters an optical power regulator. The output end of the optical power regulator is connected to one end of an analogue switch, and a biasing circuit is connected to the other end of the analogue switch. The analogue switch is controlled by a digital modulation signal. The common end of the analogue switch is connected to a second adder. One of the other two input ends of the second adder is connected with an analogue modulation end, and the other of the other two input ends of the second adder is connected with a current feedback end. The output of the second adder controls a semiconductor laser tube LD through a current regulator anda driving / protection circuit. The semiconductor laser tube LD serves as the current feedback end after passing through a feedback coefficient K2f. A diode D is connected in parallel with the two endsof the semiconductor laser tube LD. The cathode of a photoelectric tube PD serves as an optical power negative feedback end after passing through a feedback coefficient K1f. In digital modulation, first, second and third contact terminals of the analogue switch are turned on in turn; and in direct current or analogue modulation, the third contact terminal and the first contact terminal are turnedon all the time. The stable laser light source has the advantages of high modulation performance, stable laser power and high turning-off performance.
Owner:NANJING JILONG OPTICAL COMM

Multi-loop direct-current emergency power modulation system and method based on PMU (power management unit)

The invention relates to a multi-loop direct-current emergency power modulation system and a multi-loop direct-current emergency power modulation method based on a PMU (power management unit). The modulation system comprises a sensor, a PMU device, a GPS (global positioning system), a control main station and a signal transmitter, wherein the PMU device is connected with a convertor station through the sensor, the control main station is respectively in communication connection with the PMU device and the signal transmitter, the GPS is connected with the PMU device, and the signal transmitter is connected with the convertor station. The modulation method comprises the following steps of adopting the PMU device to sample each convertor station in real time, calculating a voltage phasor value and corresponding power, outputting the phasor data, and transmitting the phasor data with a time scale to the control main station according to a clock signal of the GPS; and adopting the control main station to calculate a modulation power control signal of each loop of direct-current power transmission system, and modulating the power of each convertor station according to the modulation power control signal. Compared with the prior art, the modulation system and the modulation method have the advantages that the operation stability of a power system can be improved, and the modulation effect is good.
Owner:STATE GRID CORP OF CHINA +2

Cultivation method for purple sweet potatoes and method for processing purple sweet potato powder

The invention relates to a cultivation method for purple sweet potatoes and a method for processing purple sweet potato powder and belongs to the technical fields of sweet potato cultivation and processing. A new cultivation method is obtained by changing the concentration of thiophanate methyl water solution for soaking seeds, sweet potato seedling planting time and density, fertilizer types and consumption, and types and concentration of inhibitors. According to the cultivation method, acre yield of fresh potatoes is more than 2,200kg, the large medium sized tuber rate is higher than 90.3 percent, anthocyanin content is more than 120mg/100g, and starch content is more than 31.1 percent; the yield for preparing the purple sweet potato powder from the purple sweet potatoes harvested by the cultivation method is higher than 41.6 percent. Methods of cooking, mashing, drying and pulverizing are adopted, sweet potatoes are sliced, and the sliced sweet potatoes are blanched, cooled, cooked, mashed, dried, pulverized and screened to form the purple sweet potato powder, the defect of poor cluster caused by improper color protection in the traditional process is overcome, and the processed product is bright in color, high in dispersibility and high in water absorption.
Owner:CROP RES INST SHANDONG ACAD OF AGRI SCI

Lithium niobate-based PM-QPSK integrated light modulator and working method thereof

InactiveCN105700202ASmall process toleranceHighly integratedNon-linear opticsMultiplexerSilicon
The invention relates to a lithium niobate-based PM-QPSK integrated light modulator and a working method thereof. The lithium niobate-based PM-QPSK integrated light modulator comprises an upper electrode, a lower electrode, a lining and lithium niobate crystals, wherein a polarization demultiplexer, two IQ modulators in parallel and a polarization multiplexer are sequentially etched on the lithium niobate crystals in a light path direction; the upper electrode and the lower electrode are respectively arranged on the upper surface of the lithium niobate crystals and below the lining; the polarization demultiplexer and the polarization multiplexer are respectively a lithium niobate polarization demultiplexer based on MZI and a lithium niobate polarization multiplexer based on MZI. As the lithium niobate-based PM-QPSK integrated light modulator is provided with the lithium niobate polarization demultiplexer and the lithium niobate polarization multiplexer manufactured on a birefrigent effect of lithium niobate, the conventional method that a polarization multiplexer is manufactured on the basis of a silicon substrate is changed, a polarization demultiplexer and a polarization multiplexer based on the silicon substrate and IQ modulators are integrated on the same piece of crystal, and the allowance is far smaller than a silicon substrate process.
Owner:SHANDONG UNIV

Monophase full-bridge inverter circuit and modulation method thereof

Disclosed are a monophase full-bridge inverter circuit and a modulation method thereof. The monophase full-bridge inverter circuit comprises a bus capacitor, a full-bridge inverter circuit, a filter circuit, a first reverse-resistance IGBT (insulated gate bipolar transistor) and a second reverse-resistance IGBT. Input ends M and N of the inverter circuit are correspondingly connected with a positive electrode and a negative electrode of the bus capacitor, and output ends A and B of the inverter circuit are connected with the filter circuit. A collector and an emitter of each of the first IGBT and the second IGBT are correspondingly connected with the output end A and the output end B. Each bridge arm of the inverter circuit comprises a switch tube and an inverse-joint diode, an emitter of the first bridge arm and a collector of the second bridge arm are connected with the output end A, and an emitter of the third bridge arm and a collector of the fourth bridge arm are connected with the output end B. A collector of the first bridge arm and a collector of the third bridge arm are connected with the input end M, and an emitter of the second bridge arm and an emitter of the fourth bridge arm are connected with the input end N. Based on the above circuit, the modulation method includes controlling the second IGBT to make in the positive half circle of output voltage and controlling the first IGBT to make in the negative half circle. By the monophase full-bridge inverter circuit, efficiency of inverters is improved, pulse of common mode voltage can be effectively suppressed, and modulation effect is better.
Owner:SHENZHEN HOPEWIND ELECTRIC CO LTD

Energy and information composite transmission system for implementing full duplex communication based on galvanometer

The invention provides an energy and information composite transmission system for implementing full duplex communication based on a galvanometer, and belongs to the field of laser communications. Inorder to solve the existing technical problem, a first signal source loads signals to a laser through a biasing circuit, the signals are collimated by a first collimating lens through a splitter, andthen emitted to a passive end; after a second collimating lens receives light, the light is converged to a diaphragm center; the light is transformed into parallel light via a convergent lens, then reflected to a short focal lens via the galvanometer, and the parallel light is converged to a photovoltaic cell panel via the short focal lens; corresponding electric signals are generated and the electric signals pass through a subsequent processing circuit, and light energy is collected and converted into electric energy as the working energy of the passive end; a second signal source loads the signals on a galvanometer driver and generates a control signal for the galvanometer, vibrates and makes the angle of a return light beam change with the signals, and modulates the return light beam inan OOK format; and the light beam returns along the original way, and is reflected to a plano-convex lens by the splitter; and the plano-convex lens converges the light beam to a detector, and the light beam is processed by an active end signal processing module and then upstream communication is completed.
Owner:CHANGCHUN UNIV OF SCI & TECH
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