11808 results about "Frequency conversion" patented technology

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.

A multi-mode wireless device having a transceiver including a multi-mode transmitter and a multi-mode receiver. The transmitter can include a multi-mode transmit baseband portion configured to support all of the transmit modes. Similarly, the receiver can include a multi-mode baseband portion that is configured to support all of the receive modes. The transmitter can also include a frequency conversion stage that can convert the output from the transmit baseband portion to the desired transmit frequency. Multiple power amplifiers in parallel, each configured to support one or more of the operating modes, can selectively amplify the transmit signals. The receiver can include multiple low noise amplifiers (LNAs) in parallel, each configured to selectively amplify the received signals of one or more of the operating modes. The output of the LNAs can be coupled to a frequency conversion stage that downconverts the received signals and provides them to the baseband portion.

A frequency conversion correction circuit for an electrophoretic display (EPD) which has a control circuit to capture pixel signals of a next picture and gets a corresponding update signal from a look up table to be output, and a driving circuit to provide a plurality set of potential difference signals corresponding to a plurality set of electrodes of an EPD panel according to the update signal. The EPD further has an environment detection device and a duty frequency judgment unit. The environment detection device detects the operation environments of the EPD and gets an environment parameter. The duty frequency judgment unit compares the preset signal value sections where the environment parameter is located and generates a duty frequency signal and sends to the driving circuit. The driving circuit changes and outputs the frequency of the potential difference signals in a fixed frame time according to the duty frequency signal.

A mode-locked laser with intracavity frequency conversion is disclosed. In one embodiment the conversion frequency is improved by reducing the temporal, spatial, or polarization overlap between pulses at the fundamental frequency and pulses at a frequency-shifted frequency.

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.

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.

The invention discloses an electric-drive mixing device, and relates to the technical field of mixing equipment. The electric-drive mixing device comprises a motor power unit, a mixing tank, a discharge centrifugal pump, a suction centrifugal pump, a powder tank, a control chamber, a drainage manifold, a water-powder mixing manifold, a chemical adding pump and a suction header. The mixing tank is fixedly mounted on one side of the motor power unit, and the control chamber is fixedly mounted on one side of the mixing tank. The electric-drive mixing device has the advantages that a selected motor is a variable-frequency all-in-one machine, that is to say, a frequency converter is integrated with the motor, and there is no independent frequency conversion cabinet, so that the occupied space is remarkably saved, and the device is suitable for vehicle transportation; the variable-frequency all-in-one machine has much lower heat than the motor, a radiator is integrated to a cabinet casing of the motor and the frequency converter, and no plate-fin radiating holes are provided; a large-channel air duct is arranged at a motor and frequency converter casing position of a fan, and accordingly, blockage is avoided.

Agile frequency converter and method, IF-RF level exchange process, and notch filtering techniques. System noise and spurious levels generated by channel frequency conversion is reduced in applications requiring broadband combining of frequency converters to form multichannel composite signal. Converter employs two-stage frequency conversion process, with gain exchange system using variable pre-mixer gain and variable post-mixer attenuation to maintain constant RF output signal power level. For those few conversion frequencies where distortion component(s) cannot be filtered without degrading desired signal, IF-RF level exchange is optimized for meeting the carrier-to-distortion (C/D) ratio specifications at slight expense of noise level for that channel only, while still meeting aggregate combined carrier-to-noise (C/N) specification requirements. Optimal apportionment of level exchange for each channel depends on specific frequency rejection capability of spurious components and is matched to filtering capability and stored within non-volatile memory of a microcontroller used in the frequency converter.

A probe assembly for examining a sample, the assembly including a probe, a fiber optic cable for communicating signals to and/or from the probe, an emitter for emitting radiation to irradiate the sample and an electro-magnetic radiation detector for detecting radiation which is transmitted or reflected from the sample. The emitter includes a frequency conversion member which emits radiation in response to being irradiated with input radiation which has a different frequency to that of the emitted radiation. At least one of the emitter or detector is located in the probe. The probe is particularly for use as an endoscope or for imaging teeth. The invention also extends to a method of imaging teeth, and apparatus for imaging diseased teeth, for example, teeth with caries or suffering from periodontal disease.

This invention provides a method and a system for coding/decoding frequency domain parameter stereos and multiple tracks, which converts signals of right and left tracks to a residual signal of a sum-difference tack and a residual signal of an estimated difference track, carries out time frequency conversion to residual signals of the estimated difference track, the original difference track and the original sum track to pick up the HF component and low frequency component of the residual signal of the original difference track, which is coded in quantization to utilize the HF component to get estimated residual RF component of the right and left tracks and gets the original residual RF component of the right and left tracks to be controlled in gain to get a gain coefficient of the difference of the two tracks and coded in quantization and finally multiplexes the coded data and edge information to get a frequency domain parameter stereo bit stream.

A tuner circuit includes a band selection filter coupled to receive an input RF signal and provide a band selected output signal where the band selection filter includes a bank of band pass filters. Each band pass filter includes an inductor and a variable capacitor forming an LC resonator where the inductor is an integrated planar spiral inductor. The tuner circuit further includes a frequency conversion circuit coupled to receive an input signal corresponding to the band selected output signal and provide a frequency converted output signal having a predetermined frequency. The integrated planar spiral inductor can be formed using a single metal spiral or multiple metal spirals. In a multi-spiral structure, a first metal spiral having an inward spiral pattern and a second metal spiral having an outward spiral pattern to form an inductor with large inductance, low series resistance and high Q values, even at low frequency.

The invention discloses a frequency-change radar goal emulator of millimeter wave, which comprises the following parts: control unit, transceiver unit, Doppler analog unit, distant analog unit and amplitude analog unit, wherein the radar signal enters into the Doppler analog unit through transceiver unit, which produces middle-frequency signal through lower frequency-changer and low-pass filter of the Doppler analog unit; the upper frequency-changer and band-pass filter group of Doppler analog unit produces RF signal; the difference of local oscillator frequency of upper and lower frequency-changers analogs the Doppler frequency shift of goal; the RF signal generates launching signal through changing the echo amplitude of goal simulated by amplitude analog unit, which is transmitted by transceiver unit; the control unit transmits control signal for other four units according to the analog parameter such as input distance, speed and amplitude; the radar signal passes the emulator to provide an analog signal with Doppler frequency shift, signal amplitude fluctuation and distant delay to radar, which provides estimating platform for working property testing for radar.

A Global Positioning System carries out Doppler correction of a C/A code sequence after a frequency conversion, and calculates a pseudo range by performing correlation calculation between the C/A code, which is obtained by summing up the C/A code sequence beginning from a polarity inversion boundary determined at a correlation peak detecting step ST10, and a C/A code generated in a GPS terminal. When a received electric field detected by a received electric field intensity detector 11 is good, the current position is determined from the pseudo range and the navigation data extracted by the GPS terminal itself, whereas when the received electric field is poor, the current position is determined from the pseudo range and the navigation data sent from an external apparatus.

The invention relates to scanning pulsed laser systems for optical imaging. Coherent dual scanning laser systems (CDSL) are disclosed and some applications thereof. Various alternatives for implementation are illustrated, including highly integrated configurations. In at least one embodiment a coherent dual scanning laser system (CDSL) includes two passively modelocked fiber oscillators. The oscillators are configured to operate at slightly different repetition rates, such that a difference δf_r in repetition rates is small compared to the values f_r1 and f_r2 of the repetition rates of the oscillators. The CDSL system also includes a non-linear frequency conversion section optically connected to each oscillator. The section includes a non-linear optical element generating a frequency converted spectral output having a spectral bandwidth and a frequency comb comprising harmonics of the oscillator repetition rates. A CDSL may be arranged in an imaging system for one or more of optical imaging, microscopy, micro-spectroscopy and/or THz imaging.

A low-noise laser diode module comprises a laser diode for emitting light with a wavelength in the range from UV to IR, a drive circuit for injecting electrical current into said diode, and an automatic power control circuit for monitoring and adjusting laser output power using front-facet photodiode external to the laser assembly and a feedback loop. Said drive circuit produces injection current modulated by an RF signal with variable degrees, depending on the wavelength to be stabilized, the desired spectral bandwidths of the laser output, and/or other applications. Said RF signal can be a sine wave, a distorted sine wave, a rectified sine wave, a non-sine wave, a series of narrow pulses, or repetitive shunt. The present invention encompasses a method for producing stable, broadband, and low-coherent laser. The present invention also encompasses a method for producing stable narrowband or single longitudinal mode laser. The present invention further encompasses a compact light source applicable to DPSS lasers, fiber lasers, optical parametric oscillators, low-speckle laser display systems, and seeders, with or without nonlinear frequency conversion processes.

Disclosed is a method of measuring the throughput of uplink data in a WiBro repeater, the method including the operations of: (a) extracting a plurality of tiles from a predetermined number of symbols that are collected over a plurality of times by performing frequency conversion on the uplink data; (b) calculating power values for the respective extracted tiles; (c) calculating an average noise value from the calculated power values; (d) calculating a threshold value, which is used to identify noise, from the average noise value, and calculating the number of tiles having power values more than the threshold value; and (e) calculating the throughput by estimating based on the number of the tiles the number of subchannels carrying data.