2413 results about "Phase locking" patented technology

A frequency determination circuit generating a clock signal phase-locking with an external clock signal at a coarse precision and a fine adjust circuit generating an internal synchronizing signal phase-locking with the external clock signal at a fine precision are provided. The fine adjust circuit has a function of adjusting the phase of the frequency determination circuit when phase synchronization is to be carried out exceeding the adjust range thereof. The frequency determination circuit and the fine adjust circuit receive a clock power supply voltage. A clock reproduction circuit is provided which generates an internal clock signal phase-locking with an external clock signal or a reference clock signal stably even when the operating environment changes.

Plasma distribution is controlled in a plasma reactor by controlling the phase differences between different RF coil antennas, in accordance with a desired or user-selected phase difference, by a phase-lock feedback control loop.

A method and system of interference lithography (also known as interferometric lithography or holographic lithography) which utilizes phase-locked, scanning beams (so-called scanning beam interference lithography, or SBIL). The invention utilizes a high-precision stage that moves a substrate under overlapped and interfering pairs of coherent beams. The overlapped beams interfere, generating fringes, which form a pattern “brush” for subsequent writing of periodic and quasi-periodic patterns on the substrate. The phase of the fringes in the overlapped region is phase-locked to the motion of the precision stage. The invention includes methods for forming, overlapping, and phase-locking interfering pairs of beams on a variety of substrates; methods for measuring and controlling the period, phase, and angular orientation of fringes generated by the overlapping beams; and methods for measuring and controlling the effects of stage mechanical and thermal drift and other disturbances during the writing process.

A power amplifier system and method for locating carrier frequencies across a frequency band, identifying the modulation format of each carrier, and locating and suppressing undesired intermodulation distortion (IMD) products generated by the power amplifier. The system includes an amplifier for amplifying RF carrier signals in a main signal path, a variable phase shifter and variable attenuator on a feed forward path, and a tunable receiver that digitizes a portion of the frequency band to baseband. The tunable receiver includes a tunable voltage controlled oscillator which provides an oscillating frequency to a mixer and is phase-locked to a highly stable reference oscillator. The mixer downconverts a desired RF based on the oscillating frequency to IF. A filter passes only a selected portion of the IF signals, and the filter has a passband sufficient to discern both narrowband and wideband carriers and their associated IMD products. Based on the locations of the carrier frequencies, a processing unit determines the IMD locations of the carrier frequencies, determines the IMD locations, and adjusts the variable phase shifter and variable attenuator on the feed forward path until the IMD products in the main signal path are suppressed below a desired threshold.

The present invention provides an improved method and apparatus for independently controlling phase and frequency using an oscillator having a plurality of stages in combination with a phase selector within a digitally controlled phase-locked loop, preferably, a read phase locked loop. The present invention provides a digitally controlled variable phase of the read timing loop in read channel integrated circuits associated with data storage devices. The phase selector has a digitally controlled fine interpolator with 12 states for further fine interpolation between at least two multiplexer phase outputs to provide a single phase output selected from a range comprising at least 2pi in selectable variable phase increments of 2pi/96 radian. The combined oscillator with the phase selector within a phase locked loop controls phase by exact fractional increments of equally space phases of the operating frequency within the phase locked loop, therein controlling phase at all operating frequencies.

A clock system includes a digital phase/frequency detector (DPFD), a buffer, a digitally-controlled oscillator (DCO) including a sigma-delta modulator (SDM), an adder, a first frequency divider. The DPFD may have a first input for a reference input clock and a second input for a feedback signal, and outputting a difference signal representing a phase and/or frequency difference between the reference input clock and the feedback signal. The buffer may be coupled to the DPFD for accumulating the difference signal over time. The sigma-delta modulator (SDM) may have a control input coupled to the buffer. The adder may have inputs coupled to the (SDM) and a source of an integer control word. The first frequency divider may have an input for a clock signal and a control input coupled to the adder, the DCO generating an output clock signal having an average frequency representing a frequency of the input clock signal divided by (N+F/M), wherein N is determined by the integer control word and F/M is determined by an output of the SDM. The system clock also may include a phase-locked loop (PLL) including a phase/frequency detector that has a first input coupled to the output of the DCO and a second input that is phase-locked to the first input, and a second frequency divider coupled from the second input of the PLL to the second input of the DPFD.

A parallel redundant power system and a method for control the same, wherein the power system is composed by UPS modules with outputs coupled in parallel to supply power to a load through a bus. The control method employs the P-omega and Q-V slope lines of the droop method to perform phase locking and current sharing. Moreover, the method further utilizes the internal impedance of the UPS in accompaniment with a current shift method to simulate an actual inductor being coupled to the output of the UPS module so as to satisfy the droop method. Therefore, the drawbacks otherwise caused from actual inductors such as the large size and heave weight are eliminated.

A bias generation method or apparatus defined by any one or any practical combination of numerous features that contribute to low noise and/or high efficiency biasing, including: having a charge pump control clock output with a waveform having limited harmonic content or distortion compared to a sine wave; having a ring oscillator to generating a charge pump clock that includes inverters current limited by cascode devices and achieves substantially rail-to-rail output amplitude; having a differential ring oscillator with optional startup and/or phase locking features to produce two phase outputs suitably matched and in adequate phase opposition; having a ring oscillator of less than five stages generating a charge pump clock; capacitively coupling the clock output(s) to some or all of the charge transfer capacitor switches; biasing an FET, which is capacitively coupled to a drive signal, to a bias voltage via an “active bias resistor” circuit that conducts between output terminals only during portions of a waveform appearing between the terminals, and/or wherein the bias voltage is generated by switching a small capacitance at cycles of said waveform. A charge pump for the bias generation may include a regulating feed back loop including an OTA that is also suitable for other uses, the OTA having a ratio-control input that controls a current mirror ratio in a differential amplifier over a continuous range, and optionally has differential outputs including an inverting output produced by a second differential amplifier that optionally includes a variable ratio current mirror controlled by the same ratio-control input. The ratio-control input may therefore control a common mode voltage of the differential outputs of the OTA. A control loop around the OTA may be configured to control the ratio of one or more variable ratio current mirrors, which may particularly control the output common mode voltage, and may control it such that the inverting output level tracks the non-inverting output level to cause the amplifier to function as a high-gain integrator.

A clock generator including a frequency multiplier, a phase lock circuit and a frequency divider. The frequency multiplier generates a frequency multiplied clock by multiplying the frequency of an input clock. The phase lock circuit detects a phase difference between the input clock and a frequency divided clock, and generates, by delaying the frequency multiplied clock by an amount corresponding to the phase difference, a phase-locked clock with its phase locked with the input clock. The frequency divider detects in every fixed cycle a particular pulse of the phase-locked clock, and generates the frequency divided clock by dividing the phase-locked clock with reference to the particular pulse of the phase-locked clock. In particular, the frequency divider detects the particular pulse immediately previous to a falling edge of the input clock. This can reduce the phase difference between the input clock and the phase-locked clock, and hence to solve a problem of a conventional clock generator in that a delay time of a digital delay line in a phase lock circuit must be lengthened with a reduction in the multiplication number of the frequency multiplied clock, which requires a greater number of delay elements because of a large occupying area of the delay elements and a decoder, thereby increasing the circuit scale and cost of a chip to reduce the multiplication number of the frequency multiplied clock.

The invention belongs to the technical field of gas detection and relates to a laser infrared gas analyzer based on TDLAS-WMS (tunable diode laser absorption spectroscopy-wavelength modulation spectroscopy) for detecting hydrogen chloride, methane, carbon monoxide, water vapor and other gases. The laser infrared gas analyzer comprises a laser, a laser driving circuit, a temperature control circuit, an optical system with an optical cavity, a main detector, a reference detector, an intensity modulation and canceling circuit, a phase-locking and amplification circuit and a data acquisition and display circuit, wherein the laser driving circuit and the temperature control circuit are used for controlling the laser to emit light, the two ends of the optical system are respectively connected with the laser and the detector, the intensity modulation and canceling circuit is used for canceling the influence of intensity modulation in the system, the phase-locking and amplification circuit is used for extracting harmonic signals, and the data acquisition and display circuit is used for displaying the concentration of the gas to be detected. Compared with other detection instruments, the laser infrared gas analyzer has the advantages that division operation is introduced into the intensity modulation and canceling circuit, and the laser infrared gas analyzer is combined with a space double-optical path differential detection method, so that the influence of the intensity modulation can be fundamentally canceled.

The device and method for phase-locking brain stimulation to electroencephalographic rhythms improves the accuracy, specificity, and effectiveness of non-invasive brain stimulation devices by timing pulses of brain stimulation to occur in synchrony with naturally occurring brain rhythms measured at the scalp of a patient in order to treat an assortment of neurological and psychiatric conditions. The device and method provided herein improve non-invasive brain stimulation techniques by time-locking the onset of brain stimulation to the phase of naturally-occurring rhythmic oscillations of brain activity that can be recorded with electroencephalography (EEG). The device and method perform real-time signal analysis of a specified EEG rhythm, extract frequency-domain phase information to estimate the next occurrence of a desired EEG rhythm phase, and trigger a brain stimulation pulse so as to align precisely with this predicted EEG phase.

The invention relates to a precise tracking and measuring method of a high dynamic signal of an air fleet link, belonging to the technical field of aeronautical data links and radio navigation, and aiming at providing a precise tracking and measuring method of the high dynamic signal the an air fleet link and an implementation structure to solve the problems in the prior art. The invention provides a system framework of the precise tracking and measuring method of the high dynamic signal of the air fleet link, which can be implemented on a digital signal processor (DSP) and a FPGA (field programmable gate array) of a circuit board, and overcomes the defects of the unfavorable precision of a traditional high dynamic receiver by utilizing a double-loop structure of a frequency tracking loop of carrier tracking and a phase locking loop as well as a code phase locking loop to realize the high precise tracking under a high dynamic condition. The method can be widely applied to satellite navigation receivers, range measurement systems and communication systems based on a quiescent carrier modulation direct sequence spread spectrum system.

The invention discloses a fire scene multi-parameter laser wavelength modulation spectrum detection method and a device thereof, wherein, fire smoke products are treated through a smoke pre-treatment device and then pumped into a white cell through an air extracting pump; a multi-channel laser controller scans and modulates the wavelengths of a plurality of DFB lasers according to the time-sharing and multiplexing working mode, and all waves of laser share an optical fiber and are outputted sequentially through a wave combiner, then are aligned by a fiber collimator and sent to the white cell to detect the fire smoke products; a photoelectric detector converts light intensity signals of laser repeatedly reflected and absorbed by the white cell into electrical signals which are sent to two phase-locking magnifier modules for frequency selecting magnification so as to obtain a fundamental frequency component and a second harmonic component; a multi-channel data acquisition card converts output voltage signals of the phase-locking magnifiers into digital signals which are sent to a micro-computer for real-time data processing, so that the fire scene multi-parameter information containing the oxygen concentration of the fire scene, concentrations of various toxic gases and smoke concentration is obtained. The detection method and device can realize real-time on-line monitoring to fire scene multi-parameters, and have the advantages of being real-time, multi-component and highly sensitive, good selectivity of gas, high reliability and strong environmental disturbance resistance ability.

A method for effective injection seeding is based on continuous wavelength sweeping for matching the injected seeds with one or more longitudinal mode(s) of the slave oscillator in every pulse. This is achieved through rapidly varying laser drive current, as a result of RF modulation. Depending on the modulation parameters, the seeder may be operated in CW or quasi-CW or pulsed mode, with a narrow or broad bandwidth, for injection seeding of single longitudinal mode or multimode. The wavelength and bandwidth of the laser output can be tuned according to the needs. Injection seeding of high repetition rates is achievable. From pulse to pulse, the master-slave resonance persists though may occur at different longitudinal modes upon cavity length fluctuations. Cavity length control and phase locking schemes are consequently not required. The present invention also encompasses an injection seeding laser system, which is constructed in accordance with the inventive method, and a novel application of RF modulated laser diode to spectrum/wavelength control and to producing high power Gaussian beam with narrow pulse width in a stable, reliable, and cost-effective manner.

The invention relates to a portable SF6 gas resolvent photoacoustic spectrum detecting device and method which have the advantages of being high in sensitivity, capable of automatically achieving detection and concentration conversion, fast in detection speed, high in accuracy, easy to carry and suitable for online monitoring. A paraboloid column mirror is arranged in a casing, and an infrared source is arranged on the paraboloid column mirror. A chopper, an optical filter wheel and a photoacoustic cell are arranged in front of the paraboloid column mirror, and a plurality of optical filters are evenly distributed on the optical filter wheel along the circumferential direction. The photoacoustic cell comprises a microtone device, an air pressure sensor and a temperature sensor and connected with an air pipe and a vacuum pipeline which is connected with a vacuum pump. The chopper is connected with a chopper controller, the optical filter wheel is connected with a singlechip microcomputer, the microtone device is connected with a phase-locking amplification module, the air pressure sensor is connected with the singlechip microcomputer, the temperature sensor is connected with an analog/digital (A/D) converter which is connected with the phase-locking amplification module, and the singlechip microcomputer is further connected with a liquid crystal driving and display screen and a working power source.

A method, comprising detecting, in at least a first brain region of a patient, an electrical activity relating to an epileptic activity; determining a first regularity index of said electrical activity; and applying at least one first electrical stimulation to at least one neural target of said patient for treating said epileptic event, in response to said first regularity index being within a first range. A non-transitive, computer-readable storage device for storing instructions that, when executed by a processor, perform the method. A medical device system suitable for use in the method.

The invention discloses a control method of a three-phase grid-connected inverter based on a modified proportional resonant regulator. The method comprises the following steps of: firstly, computing according to given active and reactive powers of the inverter and a voltage of a power grid to obtain required d-axis and q-axis currents under a synchronous coordinate system, and performing coordinate transformation by combining with phase information which is measured by a phase locking loop and a measured three-phase voltage signal of the power grid to obtain a current reference signal under a stationary alpha-beta coordinate system; secondly, performing coordinate transformation on an output current signal of the inverter to the alpha-beta coordinate system, controlling and tracking the current reference signal by the modified proportional resonant regulator with a harmonic compensator; and finally, returning to an abc coordinate system by coordinate transformation to generate a pulse-width modulation (PWM) pulse-control three-phase full-bridge inverter output, so as to make a distributed generation system grid-connected for power generation. By the method, a large number of complicated computation processes are eliminated, and a control structure is simplified. The control method of the three-phase grid-connected inverter based on the modified proportional resonant regulator is an accurate and high-efficiency novel inverter control method and has a bright development future.

The invention relates to a rapid locking method for a full digital phase-locked loop, which is used for locking the frequency of the full digital phase-locked loop comprising a phase detection discriminator, a time-to-digit converter, a digital filter, a digital controlled oscillator and a frequency divider in a short time. The method is characterized by comprising the following steps: finding a control word controlling the frequency of the digital controlled oscillator by a designed algorithm; dividing the frequency of a clock output by the digital controlled oscillator which is controlled bythe control word to obtain a divided-frequency clock with the frequency approximate to a reference clock frequency; and then, controlling the digital controlled oscillator to lock based on a phase difference between the reference clock and the divided-frequency clock which are distinguished by the phase detection discriminator. The full digital phase-locked loop is provided with a rapid frequencycapture loop and a phase-locked loop which alternately work, i.e. firstly, the rapid frequency capture loop finishes frequency capture, and then, the phase-locked loop finishes accurate locking.

A robust scalable laser. The laser includes plural fiber laser resonators. A cavity that is external to the fiber laser resonators combines plural laser beams output from the plural fiber laser resonators into a single output laser beam. In a specific embodiment, the plural fiber laser resonators are eye-safe double-clad Er:YAG laser resonators that are pumped via laser diode arrays.

The invention discloses a stable photoelectric oscillator. The stable photoelectric oscillator comprises a laser device, an electro-optical modulator, a long optical fiber, a photoelectric detector, an amplifier, an electric band-pass filter, an electrically-controlled microwave phase shifter, a high-stability microwave source, a 2*1 wave combiner or directional coupler, a first 1*2 power divider or directional coupler, a second 1*2 power divider or directional coupler, a third 1*2 power divider or directional coupler and a phase locking control module, wherein the phase locking control module comprises a frequency mixer, an electric low pass filter and a servo control module, the output end of the frequency mixer is connected to the input end of the electric low pass filter, and the output end of the electric low pass filter is connected to the input end of the servo control module. According to the stable photoelectric oscillator, an electric injection of the external high-stability microwave source and a phase locking control mechanism are added based on a traditional single-loop OEO structure. Compared with the prior art, the stable photoelectric oscillator has the advantages that insertion loss of an optical link in a resonant cavity is not increased, the high signal to noise ratio of the photoelectric resonant cavity is maintained, and the structural complexity of the stable photoelectric oscillator is lower than that of an existing scheme. The stable photoelectric oscillator is easy to obtain.

The invention discloses a sine-wave modulation photo plethysmo graphy measuring device and method. A microprocessor is used for outputting sine waves which are at different frequencies and are in a twifold rate relation; the sine waves are used for driving at least four light-emitting diodes; light emitted by the light-emitting diodes is received by a light-sensitive device after passing through a tested finger; the light-sensitive device is used for converting the received light into a voltage signal; the voltage signal is converted into a preset amplitude voltage signal by using a current/voltage conversion amplifier; an analog to digital converter is used for converting the preset amplitude voltage signal into a digital signal; the microprocessor is used for processing the digital signal to obtain photo plethysmo graphy and a valley value and a peak value of the photo plethysmo graphy; and a spectrum value is obtained according to the valley value and the peak value. The method comprises the following steps of: performing phase locking computation and separation processing on the digital signal to obtain photo plethysmo graphy and eliminating the interference of background light by using the microprocessor; acquiring the valley value and the peak value according to the photo plethysmo graphy; and computing the valley value and the peak value to obtain an absorbency difference value and obtaining a spectrum value according to the absorbency difference value. A circuit is simple, and the digital signal is concise.