1018 results about "Third harmonic" patented technology

YAG laser can simultaneously emit a plurality of laser beams having different wavelengths from each other. By simultaneously irradiating the laser beams having different wavelengths from each other to a same region of a non-single crystal semiconductor film, an interference influence is suppressed to obtain a more uniform laser beam. For example, by simultaneously generating second and third harmonics of YAG laser to irradiate the same region through suitable optical system, a laser beam having higher uniformity and having an energy in which interference is highly suppressed is obtained.

The present invention relates to an ultrasound imaging system in which the scan head includes a beamformer circuit that performs far field subarray beamforming or includes a sparse array selecting circuit that actuates selected elements. When using a hierarchical two-stage or three-stage beamforming system, three dimensional ultrasound images can be generated in real-time. The invention further relates to flexible printed circuit boards in the probe head. The invention furthermore relates to the use of coded or spread spectrum signalling in ultrasound imaging systems. Matched filters based on pulse compression using Golay code pairs improve the signal-to-noise ratio thus enabling third harmonic imaging with suppressed sidelobes. The system is suitable for 3D full volume cardiac imaging.

Embodiments of the invention may provide for a CMOS antenna switch, which may be referred to as a CMOS SPDT switch. The CMOS antenna switch may operate at a plurality of frequencies, perhaps around 900 MHz, 1.9 GHz and 2.1 GHz according to an embodiment of the invention. The CMOS antenna switch may include both a receiver switch and a transmit switch. The receiver switch may utilize a multi-stack transistor with body substrate switching and attachment of external capacitor between drain and gate to block high power signals from the transmit path as well as to maintain low insertion loss at the receiver path. Exemplary embodiments of the CMOS antenna switch may provide for 38 dBm P 0.1 dB at multi bands (e.g., 900 MHz, 1.8 GHz, and 2.1 GHz). In addition, −60 dBc second and third harmonic performance up to 30 dBm input, may be obtained according to example embodiments of the invention.

An optically pumped semiconductor laser includes an active ring-resonator having two or more optically pumped semiconductor (OPS) structures each including a mirror-structure and a multilayer gain-structure. The mirror-structures serve as fold mirrors for the resonator axis. An optically nonlinear crystal may be included in the ring-resonator for generating second-harmonic radiation from fundamental radiation generated in the resonator. Another optically nonlinear crystal may be provided for generating third-harmonic or fourth-harmonic radiation from the second-harmonic radiation. In one example, including a third-harmonic generating crystal, a passive ring-resonator partially coaxial with the active ring-resonator is provided for circulating second-harmonic radiation to provide resonant amplification of the second-harmonic radiation for enhancing third-harmonic conversion. Apparatus for automatically maintaining the passive ring-resonator in a resonant condition for the second-harmonic radiation is disclosed.

In a vocoder system, the receiver is arranged to emphasize at least the fundamental or lowest-frequency sinusoidal signal in response to the pitch, in a manner which provides more emphasis at lower pitch values, corresponding to larger pitch intervals. The emphasis provides a subjectively improved speech synthesis. In a preferred embodiment, the enhancement takes place at fundamental component frequencies below 400 Hz. According to another aspect of the invention, the second and third harmonics are also emphasized, but generally not as much as the fundamental component. Below certain frequencies, the enhancement is limited for the fundamental and the harmonics.

The invention is suitable for the field of radio frequency communication, and provides a double-stage inversing D-class power amplifying circuit and a radio frequency power amplifier. The circuit comprises an input passive component connected with a block condenser, a positive and negative double-way driving-stage F-class amplifier, a positive and negative double-way amplifying-stage inversing F-class amplifier and an output passive component, wherein the two input ends of the positive and negative double-way driving-stage F-class amplifier are connected with the two output ends of the input passive component through two block coupling condensers, the two input ends of the positive and negative double-way amplifying-stage inversing F-class amplifier are connected with the two output ends of the positive and negative double-way driving-stage F-class amplifier through two condensers, and the two input ends of the output passive component are connected with the two output ends of the positive and negative double-way amplifying-stage inversing F-class amplifier through the two condensers. By utilizing an F-class driving inversing F-class push-pull structure, according to the harmonic shaping technology, the efficiency, the power and the gain of the power amplifier are improved, the independent control from a fundamental wave to a triple frequency harmonic impedance is achieved, the design difficulty is lowered, and the tedious debugging work in the later period is lowered. In addition, due to the positive and negative double-way structural design, the power and the gain are further improved.

A system and method for detecting high resistance ground faults in a power distribution system is disclosed. A fault detection and protection system is provided that includes a plurality of current sensors to measure current on the three phase output of the converter-inverter arrangement of the power distribution system and a controller configured to measure the three phase current on the three phase output, extract a fundamental current component for each phase of the three phase output, extract a third harmonic component for each phase of the three phase output, compare the fundamental current component and the third harmonic component extracted from each phase to a first threshold and a second threshold, respectively, and detect a ground fault on a phase of the three phase output based on the comparisons of the fundamental current component and the third harmonic component to the first and second thresholds.

A novel and useful oscillator topology demonstrating an improved phase noise performance that exploits the time-variant phase noise model with insights into the phase noise conversion mechanisms. The oscillator is based on enforcing a pseudo-square voltage waveform around an LC tank by increasing the third-harmonic of the fundamental oscillation voltage through an additional impedance peak. Alternatively, the oscillator is based on enforcing clipped oscillation waveform by increasing the second harmonic of the fundamental oscillation voltage through an additional impedance peak. This auxiliary impedance peak is realized by a transformer with moderately coupled resonating windings. As a result, the effective impulse sensitivity function (ISF) decreases thus reducing the oscillator's effective noise factor such that a significant improvement in the oscillator phase noise and power efficiency are achieved.

A third harmonic distortion corrector is equipped for correcting a third harmonic distortion contained in a two-phase sinusoidal signals with different phases output from an encoder. A third harmonic calculator/detector calculates the amplitude a₃ and the phase φ₃ of the third harmonic using Fourier analysis, based on change in radius r of the Lissajous waveform output from a r-θ converter. The third harmonic distortion corrector corrects the third harmonic distortion of the two-phase sinusoidal signal A4, B4 based on the amplitude a₃ and the phase φ₃ of the third harmonic calculated.

Disclosed is a harmonic cancellation circuit for an RF switch branch having a first transistor with a first gate terminal and a first body terminal, a second transistor having a second gate terminal coupled to the first body terminal, and having a second body terminal coupled to the first gate terminal. Also included is a first resistor coupled between a first coupling node and the second body terminal, and a second resistor coupled between a second coupling node and the first body terminal, wherein the first transistor and second transistor are adapted to generate an inverse phase third harmonic signal relative to a third harmonic signal generated by the RF switch branch, such that the inverse phase third harmonic signal is output through the first resistor and the second resistor to the RF switch branch to reduce the third harmonic signal.

The invention provides a noncontact electric energy and signal synchronous transmission system and a control method thereof, wherein the noncontact electric energy and signal synchronous transmission system and the control method belong to synchronous transmission systems and control methods thereof. The noncontact electric energy and signal synchronous transmission system comprises a DC voltage link, a high-frequency inversion link, a primary side energy conversion link, a secondary side energy conversion link, a primary side signal modulation link, a secondary side signal demodulating link and a load. The high-frequency inversion link is parallelly connected with the primary side energy conversion link and the primary side signal modulation link, thereby respectively forming a fundamental wave extraction channel and a third harmonic extraction channel. Through switching on and off a switching device in the primary side signal modulation link, the signal is loaded in a third harmonic channel circuit. A signal current is coupled with the primary side energy conversion link through a unity-coupled transformer. After an energy current and the signal current are simultaneously transmitted to the secondary side by a same loose coupling magnetic path mechanism, the energy current is separated from the signal current through the secondary side energy conversion link and the secondary side signal demodulating link, thereby realizing simultaneous transmission of the electric energy and the signal. The noncontact electric energy and signal synchronous transmission system and the control method thereof further have advantages of stable output power, high signal transmission rate, small size and high efficiency.

An overmodulation PWM control unit includes a voltage amplitude calculating unit for calculating a voltage command amplitude of an original voltage command based on current feedback control, a voltage amplitude correcting unit performing linear compensation on the voltage command amplitude so that a fundamental amplitude of a pulse width modulation voltage provided from an inverter may match the original voltage command amplitude, and a harmonic determining unit for determining presence or absence of superimposition of a three-order harmonic component on a phase voltage command. The harmonic determining unit performs switching between presence and absence of the three-order harmonic component based on transition of the original voltage command amplitude to avoid passing through a change point where discontinuity occurs in the voltage amplitude characteristics representing a relationship between a fundamental amplitude obtained in advance for each of the cases of presence and absence of the superimposition of the three-order harmonic component and the voltage command amplitude required for achieving the fundamental amplitude.

A method for forming a stent and for also forming channels in the outer surface of selected regions of the stent structure. The method includes impinging a laser beam generated by a diode pumped Q-switched pulsed Nd/YAG laser operating at the third harmonic on an outer surface of a stent and controllably machining channels in the outer surface of the stent. The depth of the channels may be controlled by adjusting the power and pulse rate of the laser, and also by adjusting the rate at which the stent moves relative to the laser beam.

The invention relates to a multi-mode non-linear optical microscopy imaging method and device. The multi-mode non-linear optical microscopy imaging device mainly comprises a laser system, an optical scanning microscope and a non-linear optical signal detecting and acquiring system. The multi-mode non-linear optical microscopy imaging device can work in a single-laser-beam mode and a dual-laser-beam mode and can realize multi-mode non-linear optical microscopy imaging such as two-photon excited Fluorescence (TPEF) imaging, multiphoton high-order harmonic (such as second harmonic generation SHG, and third harmonic generation THG) scattering imaging, coherent Raman scattering (such as anti-Stokes CARS) microscopy imaging) on isolated biological tissues and living cells, so that various non-linear specific optical signals of biological tissue samples can be obtained in situ, so that the important basis is provided for the optical diagnosis and deep analysis of the samples. Besides, a reflection measurement manner disclosed by the invention can be further directly applied to the acquiring of various non-linear specific optical signals of live animals and the microscopy imaging.