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114results about How to "Wide spectrum" patented technology

Mine mobile communication system

The invention discloses a mine mobile communication system, which consists of an Ethernet passive optical network of a double-bus or double-loop structure, a wireless access network, a control system and an explosion-proof mobile station. The system comprises an optical link terminal, a base station controller, a ground base station, office-end equipment, passive optical splitters, explosion-proof optical network terminals, an underground explosion-proof base station, leakage antennae, base station antennae, distributed antennae and the explosion-proof mobile station, wherein the optical link terminal is connected with the ground base station and the base station controller; the explosion-proof optical network terminals are connected with the underground explosion-proof base station; the underground explosion-proof base station is connected with the leakage antennae, the base station antennae and the distributed antennae; and the explosion-proof mobile station is connected with the underground explosion-proof base station and the ground base station through a wireless interface. The mine mobile communication system has the characteristics of simple structure, flexible deployment, convenient maintenance, relatively lower cost, strong disaster resistance and anti-jamming capacity, capability of eliminating dead zones in communication and meeting requirements on a specific service environment and security for mining, and suitability for underground mobile communication in a coal mine.
Owner:CHINA UNIV OF MINING & TECH (BEIJING)

Spacing-adjustable soliton optical frequency comb system based on micro nano resonant cavity and adjusting method thereof

The invention provides a spacing-adjustable soliton optical frequency comb system based on a micro nano resonant cavity and an adjusting method thereof. The adjusting method comprises three steps of amplifying an after-filtering pumping micro nano resonant cavity by means of a single light source, finding out a wavelength range of the pumping light which can be coupled and enter the micro nano resonant cavity, and determining wavelength range of a corresponding bistable area which is generated by solitons; generating an optical frequency comb by a single-light-source pumping resonance cavity of which the wavelength is a corresponding value when an in-chamber power which is recorded in the first step begins to increase; and finally adjusting the wavelength of the single-light-source in the second step to the wavelength which corresponds with a bistable area, simultaneously adding another light source of which the wavelength is lower than N-time FSR of the light source, coupling the two light sources in the resonant cavity, and obtaining the soliton optical frequency comb through gradual evolution. When the frequency interval of the pumping light source is N-time FSR, the spectral line interval of the soliton optical frequency comb is N-time FSR correspondingly. The distance-adjustable soliton optical frequency comb system can generate the soliton optical frequency comb with adjustable spectral line spacing and realizes no consideration for pumping light wavelength adjusting rate.
Owner:SHANGHAI JIAO TONG UNIV

Device and method for controlling a satellite tracking antenna

A device for controlling a satellite tracking antenna. An azimuth drive is configured to impart an azimuthal rotational motion to the antenna about an azimuth axis. An elevation axis drive is configured to impart a rotational motion to the antenna about an elevation axis orthogonal to the azimuth axis. A tilt axis drive is configured to impart a rotational motion to the antenna about a tilt axis. The tilt axis is connected to the elevation axis in such a way that the rotational freedom of motion of the antenna about the tilt axis is dependent on the elevation angle such that: at an elevation angle of 0° the rotational freedom of motion of the antenna about the tilt axis corresponds to the azimuthal rotational motion; at an increasing elevation angle the rotational freedom of motion about the antenna successively transcends into a roll rotation; and at an elevation angle of 90° the rotational freedom of motion of the antenna about the tilt axis corresponds to a roll rotation about a roll axis orthogonal to the azimuth axis and to the elevation axis. A control controls the operation of the azimuth axis drive, the elevation axis drive, and the tilt axis drive. The control includes a true north seeking gyro for tracking position, orientation, direction and speed of movement of the device. The control further includes an additional gyro comprising an elevation gyro axis arranged to sense the elevation movement and a tilt gyro axis arranged to sense the tilt movement, so as to minimize the angular velocity of the antenna pointing vector. A method for controlling a satellite tracking antenna, and a vessel including the device.
Owner:SAAB AB

Mixed spread spectrum communication system and working method thereof

ActiveCN101594165AWide spectrumIncrease the function of random jumpTransmissionAnti jammingConfidentiality
The invention relates to a mixed spread spectrum communication system and a working method thereof, and belongs to the technical field of communication. The system comprises a sending terminal and a receiving terminal, wherein the sending terminal comprises a baseband modulator, a first mixer, a first direct digital frequency synthesizer, a first frequency synthesizer, a transmission radio frequency processing module and a first antenna; and the receiving terminal comprises a second antenna, a receiving radio frequency processing module, a second mixer, a third mixer, a second frequency synthesizer, a second direct digital frequency synthesizer, an intermediate frequency processing module, a modulus converting module and a baseband processing module. The method comprises the following steps that: the sending terminal carries out direct sequence spread spectrum and hopping frequency carrier wave modulation on transmitted data to generate a hopping frequency radio frequency signal, and sends the hopping frequency radio frequency signal; and the receiving terminal receives the hopping frequency radio frequency signal, and carries out down-frequency conversion demodulation and baseband processing on the hopping frequency radio frequency signal to obtain output data. The system and the method can improve the confidentiality and the anti-jamming performance of a mobile communication system.
Owner:SOI MICRO CO LTD

Measurement system and method for detecting orientation and size of underwater target on basis of laser sound source

The invention discloses a measurement system and method for detecting the orientation and the size of an underwater target on the basis of a laser sound source. According to the measurement system and method, the sound source is generated through lasers, laser energy is converted into sound wave energy, an acousto-optical coupling interference type optical fiber hydrophone array serves as a receiving sensor, the defects that in the optical measurement process, optical waves which are used are large in attenuation and the measuring distance is short are overcome, the defects of a sonar sensor in traditional acoustics detection are overcome, and the advantages that mobility and flexibility are high are achieved. Meanwhile, a sound source signal is generated through a laser-induced sound system, and generated sound signals have the advantages of being high in sound pressure level, wide in frequency spectrum, capable of conducting non-contact type control, and the like. An acousto-optical coupling interference type optical fiber hydrophone is used as the acoustic signal sensor, and the acoustic signal sensor has the advantages of being capable of detecting underwater acoustic signals in the non-contact mode, high in mobility, small in size, flexible in structural design, and the like.
Owner:ZHEJIANG UNIV

Anti-interference remote monitoring system based on power system maintenance

The invention discloses an anti-interference remote monitoring system based on power system maintenance. The anti-interference remote monitoring system comprises a monitoring center and multiple cap bodies which are connected with the monitoring center in a communication way. The monitoring center is connected with each cap body in a communication way so as to acquire data information transmitted by each cap body. In the transmission process of the acquisition data of the monitoring center, frequency modulation is performed on the acquisition data, the frequency spectrum under information transmission is modulated into broadband signals to be transmitted to channels for transmission, and then the broadband signals are demodulated at a receiving end by utilizing corresponding means so as to acquire the communication mode of the transmission information. The signal frequency spectrum is greatly extended by frequency modulation so that the signal anti-interference performance is enabled to be high and the error rate is low. Bandwidth occupied by the acquisition signals in transmission in the channels is relatively wide, and the receiving end adopts the correlated detection method for modulation and then the useful broadband information signals are recovered and demodulated into the acquisition signals so that the signal-to-noise ratio is high and the effects of high anti-interference performance and low error rate can be achieved.
Owner:国网山东省电力公司惠民县供电公司

Variable-depth cable ghost wave suppression method based on wave equation boundary value inversion

The invention relates to a variable-depth cable ghost wave suppression method based on wave equation boundary value inversion. The method includes the following steps: 1) extracting a common-shot-point gather from seismic data collected by a variable-depth cable; 2) performing one-dimensional Fourier transform on the seismic data of a certain shot of the common-shot-point gather to obtain a frequency spectrum containing ghost wave seismic data; 3) calculating frequency domain seismic data U<AB> containing ghost waves corresponding to a certain frequency omega in the frequency spectrum; 4) calculating G1 and G2 according to detection point depth H<0><(2)>; 5) calculating frequency domain seismic data F<CD> after ghost wave suppression which are corresponding to the frequency omega according to U<AB>, G1 and G2; 6) performing steps 3) to 5) on all frequencies omega on the frequency spectrum in the common-shot-point gather to obtain frequency domain seismic data after ghost wave suppression; 7) performing steps 2) to 6) on other shots in the common-shot-point gather to obtain frequency domain seismic data after ghost wave suppression; and 8) performing inverse Fourier transform on frequency domain seismic data F<CD> after ghost wave suppression to obtain a common-shot-point gather after ghost wave suppression. The variable-depth cable ghost wave suppression method based on wave equation boundary value inversion can be used in the processing process of seismic data collected by a maritime variable-depth cable.
Owner:CHINA NAT OFFSHORE OIL CORP +1

Variable switching frequency PWM control method suitable for single-phase MMC

The present invention discloses a variable switching frequency PWM (Pulse Width Modulation) control method suitable for a single-phase MMC (modular multilevel converter). The method comprises the steps of: regulating the carrier frequency of a single-phase MMC, and regulating the switching period duration of the PWM pulses generated based on comparison of the carrier signals to control the switching frequency of the single-phase MMC driven by the PWM pulses and allow the switching frequency of the single-phase MMC to be changed with the change of the load current, wherein the switching frequency is continuously changed near the fixed switching frequency, a mean switching frequency is unchanged, the mean switching frequency is the same as the fixed switching frequency, when the load currentis zero, the switching frequency is the maximum, and when the load current is the maximum, the switching frequency is the minimum. For large-power application occasions for the MMC, the optimizationof the switching loss is taken as a target to control the switching frequency of the inverter system, on the premise of maintaining the mean switching frequency unchanged, the switching loss of the system is reduced; and moreover, relative to the PWM algorithm of the fixed switching frequency, the current harmonic spectral distribution is wider so as to effectively reduce the system conduction EMI(Electromagnetic Interference).
Owner:HUAZHONG UNIV OF SCI & TECH

Pulse ultra-wideband ranging system

The invention relates to a pulse ultra-wideband ranging system, comprising a control circuit, a first signal generation circuit, a second signal generation circuit, an oscillator, a power amplifier, an antenna, a low noise amplifier, a detection circuit, a comparing circuit and a pulse stretching circuit. A controller controls the first signal generation circuit and the oscillator to generate an ultra wideband pulse signal which is amplified and transmitted through the antenna; after the ultra wideband pulse signal encounters a target, a refection signal is amplified through the low noise amplifier and an echo envelope signal is detected by the detection circuit, and the echo envelope signal generates an echo effective pulse after passing through the comparing circuit; the controller delays for a certain time and controls the second signal generation circuit and the echo effective pulse to generate a target effective pulse; and the target effective pulse is stretched to be a stretching signal by the pulse stretching circuit and the stretching signal is sent to the control circuit, and the control circuit judges whether the target is on the specified distance or not based on the condition whether the stretching signal exists or not. The invention simply solves the problems of generation, transmission and detection of the ultra wideband signal, and facilitates the mini-sized design.
Owner:湖北三江航天红林探控有限公司
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