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9227 results about "Frequency conversion" patented technology

Apparatus and method for the generation of high-power femtosecond pulses from a fiber amplifier

An apparatus generates femtosecond pulses from laser amplifiers by nonlinear frequency conversion. The implementation of nonlinear frequency-conversion allows the design of highly nonlinear amplifiers at a signal wavelength (SW), while still preserving a high-quality pulse at an approximately frequency-doubled wavelength (FDW). Nonlinear frequency-conversion also allows for limited wavelength tuning of the FDW. As an example, the output from a nonlinear fiber amplifier is frequency-converted. By controlling the polarization state in the nonlinear fiber amplifier and by operating in the soliton-supporting dispersion regime of the host glass, an efficient nonlinear pulse compression for the SW is obtained. The generated pulse width is optimized by utilizing soliton compression in the presence of the Raman-self-frequency shift in the nonlinear fiber amplifier at the SW. High-power pulses are obtained by employing fiber amplifiers with large core-diameters. The efficiency of the nonlinear fiber amplifier is optimized by using a double clad fiber (i.e., a fiber with a double-step refractive index profile) and by pumping light directly into the inner core of this fiber. Periodically poled LiNbO3 (PPLN) is used for efficient conversion of the SW to a FDW. The quality of the pulses at the FDW can further be improved by nonlinear frequency conversion of the compressed and Raman-shifted signal pulses at the SW. The use of Raman-shifting further increases the tuning range at the FDW. For applications in confocal microscopy, a special linear fiber amplifier is used.

Radio communication system

There is disclosed a radio communication system in which a constitution of a base station and further a control station can be simplified. A radio communication system according to the present invention converts a received signal received by a plurality of antenna elements in a base station to a signal of different frequency band, and then conflates the converted signal in order to generate sub-carrier wavemultiplex signal. The signal is converted to an optical signal, and then the optical signal is transmitted to a control station via an optical fiber. Or the control station performs weighting to phase of the transmitted signal transmitted from a plurality of antennas of a base station, and then performs frequency conversion to different frequency band, and then conflates the converted signal in order to generate the sub-carrier wave multiplex signal. The signal is converted to an optical signal, and then an optical signal is transmitted to the base station side via the optical fiber. The control station and the base station divides the received sub-carrier wave multiplex signal by each frequency band, and then the frequency of the divided signals are converted to the same frequency band in order to generate the transmitted / received signal of each antenna element. By such a constitution, it is possible to reduce constituent of the optical transmission components to the minimum and to simplify the constitution of the base station. Furthermore, it is possible to maintain the relative phase difference and the relative intensity of the transmitted / received signal of each antenna element. Because of this, it is possible to estimate an arrival direction of the received signal and to control radiation beam pattern of the transmitted signal.

Structure and method for super FET mixer having logic-gate generated FET square-wave switching signal

A mixing method and mixer structure provide a circuit topology suitable for use in radio receivers, transmitters, tuners, instrumentation systems, telemetry systems, and other systems and devices performing frequency conversion in either homodyne or heterodyne implementations. The inventive mixer may be used for wireless communication devices including radios, cellular telephones, and telemetry systems whether land, sea, airborne, or space based, and whether fixed or mobile. The mixer provides superior intermodulation and harmonic distortion suppression and features excellent conversion loss, noise figure, port match, and port isolation as a result of its circuit topology. The mixer device circuit combines the advantages of series mixing FETs, a triple balanced design using a balanced passive reflection transformer, a precise local oscillator phase splitter, and square wave gate drive having high slew rate signal characteristics to achieve high levels of performance. It is power conservative and offers the advantage of long battery life in portable devices such as portable radios and cellular telephones as it requires only a modest amount of DC and local oscillator drive power, and is useful for operation over at least a multi-decade bandwidth.

Electric drive fracturing semi-trailer of frequency conversion integrated machine

The invention discloses an electric drive fracturing semi-trailer of a frequency conversion integrated machine. The optimization and integration of the traditional power supply semi-trailer and the fracturing semi-trailer realize the functions of power supply and fracturing of one semi-trailer without using the complete set of the power supply semi-trailer and the fracturing semi-trailer, the electric drive fracturing semi-trailer is more flexible in actual use, and the well field layout of oil and gas fields is greatly optimized; the transportation is convenient; only a set of high-voltage cables can be connected with the high-voltage power supply to reach a working state, and the wiring installation is faster; compared with diesel-driven fracturing, and the noise of the electric drive fracturing is low without exhaust emission pollution; the driving source is power, which has lower cost than the diesel; the electric drive fracturing semi-trailer adopts an integrated design of a motorand a frequency converter (namely, the frequency conversion integrated machine), the space occupied by the electric motor and the inverter in the prior art is reduced effectively, so the installing part of the electric drive fracturing semi-trailer has smaller volume and the transportation is more convenient, and can also provide space guarantee for installing other equipment on the semi-trailerbody.

DC frequency converting air-conditioner compressor intelligent controller and control method thereof

The invention provides an intelligent controller used for a direct current (DC) frequency-conversion air conditioner compressor and a technical proposal of the control method thereof; the hardware proposal comprises a rectifier filter circuit and a power module which are electrically connected sequentially; the rectifier filter circuit (220) is also electrically connected with a single DSP controller used as a core processing unit by a switch power supply (240); the single DSP controller is also respectively and electrically connected with the power module, a communication isolation circuit which is used for communicating with the indoor machine of the air conditioner, a fan driving circuit (280), and a temperature sampling circuit (270); the control method comprises the steps as follows:the control software is embedded in the DSP controller; by a control type of dual close-ring FOC no-sensor magnetic field vector, the current ring at the internal ring realizes the decoupling controlto the driving current of the permanent magnetic synchronous motor of a compressor and indirectly controls the output torque of the motor; the speed ring at the external ring is used for controlling the working frequency of the compressor, thus not only meeting the stable requirement during fixed frequency but also meeting the dynamic response during the frequency conversion; and the control software comprises a primitive recursive function and a main interrupt function.

Modular, high energy, widely-tunable ultrafast fiber source

A modular, compact and widely tunable laser system for the efficient generation of high peak and high average power ultrashort pulses. Modularity is ensured by the implementation of interchangeable amplifier components. System compactness is ensured by employing efficient fiber amplifiers, directly or indirectly pumped by diode lasers. Peak power handling capability of the fiber amplifiers is expanded by using optimized pulse shapes, as well as dispersively broadened pulses. Dispersive broadening is introduced by dispersive pulse stretching in the presence of self-phase modulation and gain, resulting in the formation of high-power parabolic pulses. In addition, dispersive broadening is also introduced by simple fiber delay lines or chirped fiber gratings, resulting in a further increase of the energy handling ability of the fiber amplifiers. The phase of the pulses in the dispersive delay line is controlled to quartic order by the use of fibers with varying amounts of waveguide dispersion or by controlling the chirp of the fiber gratings. After amplification, the dispersively stretched pulses can be re-compressed to nearly their bandwidth limit by the implementation of another set of dispersive delay lines. To ensure a wide tunability of the whole system, Raman-shifting of the compact sources of ultrashort pulses in conjunction with frequency-conversion in nonlinear optical crystals can be implemented, or an Anti-Stokes fiber in conjunction with fiber amplifiers and Raman-shifters are used. A particularly compact implementation of the whole system uses fiber oscillators in conjunction with fiber amplifiers. Additionally, long, distributed, positive dispersion optical amplifiers are used to improve transmission characteristics of an optical communication system. Finally, an optical communication system utilizes a Raman amplifier fiber pumped by a train of Raman-shifted, wavelength-tunable pump pulses, to thereby amplify an optical signal which counterpropogates within the Raman amplifier fiber with respect to the pump pulses.

Control method for improving comfortability of frequency conversion air conditioner wind-discharging temperature

A control method for improving comfortability of frequency conversion air conditioner wind-discharging temperature is characterized in that before opening the refrigeration / heat-production of the frequency conversion air conditioner, the frequency conversion air conditioner runs in a precooling / preheating mode, by means of alterring an operation frequency of a compressor and an operation frequency of a fan of an outdoor heat excharger. The control method includes the following steps: opening the precooling / preheating mode; the compressor operates at a first rotary speed during a first period; the fan of the outdoor heat excharger operates at a second rotary speed during the first period; opening the refrigeration / heat-production mode, the fans of the compressor and the outdoor heat excharger operate at a normal rotary speed. The first rotary speed is a speed having a frequency number of 0-37.5Hz, the second rotary speed is a speed having a frequency number of 0-30Hz. By means of the invention, it is capable of ensuring a temperature of an air outlet of an indoor set of the air conditioner to be a user setting temperature stably, so as to reduce a time for cool-down of the air conditioner.

Intelligent defrosting method for frequency-conversion air conditioner

The invention provides an intelligent defrosting method for a frequency-conversion air conditioner. Whether the air conditioner enters a defrosting program or not is judged according to a series of comprehensive factors such as the ranges of the indoor coil temperature, the indoor environment temperature, the outdoor coil temperature and the outdoor environment temperature, differences of the corresponding temperatures and heating running duration and cumulative time, the defrosting exit condition is determined according to the factors such as the defrosting duration and the range of the outer machine coil temperature, and the technical problems that in the prior art, the defrosting condition is simply set, and consequently the phenomena that defrosting is wrongly conducted when frost does not exist, defrosting is frequently conducted when frost is thin, and defrosting is not conducted when frost is thick possibly happen, and the heating effect of the air conditioner is affected can be solved. According to the intelligent defrosting method for the frequency-conversion air conditioner, the intelligent degree of defrosting of the air conditioner can be improved, the effects that defrosting is conducted when frost exists, defrosting is not conducted when frost does not exist, defrosting begins when frosting reaches a certain degree, and defrosting of an outdoor unit is thorough and timely can be improved, the accurate defrosting efficiency of the air conditioner can be effectively improved, and the heating performance of the air conditioner is improved.
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