65results about How to "High modulation frequency" patented technology

System and method for regulating a power converter. The system includes a first comparator configured to receive a first input signal and a second input signal and generate a first comparison signal based on at least information associated with the first input signal and the second input signal, a pulse-width-modulation generator configured to receive at least the first comparison signal and generate a modulation signal based on at least information associated with the first comparison signal, a driver component configured to receive the modulation signal and output a drive signal to a switch to adjust a primary current flowing through a primary winding of the power converter, and a voltage-change-rate detection component configured to sample the feedback signal to generate a first sampled signal for a first modulation period and to sample the feedback signal to generate a second sampled signal for a second modulation period.

A novel radiation detector, a detection principle and an associated structure are provided for semiconductor substrate detectors in general and for CMOS based circuits in particular. For an optical detector, photons absorbed in the neutral zone of the substrate generate electron hole pairs that migrate by diffusion. A shadow mask gives a spatial modulation to the incident, and consequently, to the absorbed light in the semiconductor substrate. By measuring the magnitude of the spatial frequency component in the minority carrier distribution with a spatial frequency corresponding to that of the shadow mask, a fast detector is conceived. A shadow mask with higher spatial modulation frequency delivers a faster turn-off. The combination of a plurality of these detectors with an image fiber forms a basic system for constructing high-speed parallel optical interconnects between chips.

A method and apparatus for two-dimensional gas chromatography (GC), including a valve having first and second positions (P1, and P2), and first through fourth sample flow paths (FP1-FP4). In P1, a first gas sample is collected from a first dimension GC column via FP1, a first pressure source and a first, second dimension GC column are connected via FP2, a second pressure source and a second, second dimension GC column are connected via FP3, and FP4 is disconnected. In P2, the first sample in FP1 is introduced to the second, second dimension GC column via FP1, with aid of the second pressure source, a second gas sample is collected from the first dimension GC column via FP2, the first pressure source and the first, second dimension GC column via FP4 are connected, and FP3 is disconnected.

A light emitting element emits a modulated light modulated in a pattern having a repetitive period toward a space. A driving unit drives the light emitting element. A light receiving element distributes charges corresponding to an incident light containing a reflected light obtained by reflecting the modulated light on an object to storage capacitors and stores the distributed charges. A control unit controls an exposure of the light receiving element. A signal processing unit measures a distance to the object by using a value sampled by the light receiving element. The control unit controls the exposure of the light receiving element to give a sensitivity to at least one high-order harmonic. The signal processing unit linearly combines a component of a fundamental wave with a component of the at least one high-order harmonic to measure the distance to the object.

The invention discloses a rotating transformer exciting circuit based on sinusoidal pulse width modulation (SPWM), which comprises a microprocessor, an analog demodulation circuit and a power amplification circuit, wherein the microprocessor adopts DSP to perform digital modulation so as to load a required sinusoidal fundamental wave signal to a high-frequency square wave carrier signal to form an SPWM wave signal, and output SPWM waves to the analog demodulation circuit in a differential mode. The analog demodulation circuit adopts a two-circuit duplicate-supply operational amplifier TL082, and one path of the operational amplifier forms a differential proportion calculator, while the other path forms a filter. The power amplification circuit adopts a two-circuit duplicate-supply linear power amplifier PA60 and a resistor to form a two-circuit reversed phase proportioner, and blocks the input sinusoidal fundamental wave signal and amplifies the power to generate an exciting signal and simultaneously drive a two-circuit rotating transformer to work. The rotating transformer exciting circuit has the advantages of simple circuit, safety and reliability, small temperature drift and direct current component, good stability of output signals, and low degree of distortion of output waveforms.

A microprocessor-based controller is provided for generated heat in at various locations in an exhaust system of an engine by changing the heat generation technique utilized. In one case, some cylinder air-fuel ratios are modulated between stoichiometry and rich, while others are modulated between stoichiometry and lean. Another approach operates some cylinder lean, while others are modulated between a first rich, and a second, less rich, value. Further, compensation based on engine airflow is also provided. Finally, various methods are described for temperature control and for controlling modulation of air-fuel ratio.

A method and apparatus for two-dimensional gas chromatography (GC), including a valve having first and second positions (P1, and P2), and first through fourth sample flow paths (FP1-FP4). In P1, a first gas sample is collected from a first dimension GC column via FP1, a first pressure source and a first, second dimension GC column are connected via FP2, a second pressure source and a second, second dimension GC column are connected via FP3, and FP4 is disconnected. In P2, the first sample in FP1 is introduced to the second, second dimension GC column via FP1, with aid of the second pressure source, a second gas sample is collected from the first dimension GC column via FP2, the first pressure source and the first, second dimension GC column via FP4 are connected, and FP3 is disconnected.

The high-speed road-band photoelectronic transmission TO-CAN groupware of TO package comprises a base, an optical silicon platform with a V-shaped slot composed of a LD and a photoelectric detector, a thermal fin, and a photoelectric module composed of a choke coil of high-frequency current connected to LD and photodiode of detector and base, an impedance circuit composed of signal circuit and plane plate, a spiral film coil and a matching resistance bonded to LD by lead wire and integrated in silicon platform by film technology. This invention is convenient to high-speed transmission, and raises greatly the modulation frequency for high-speed emission.

A nephelometer for detecting the concentration of particulates in a sample aerosol is provided with a branched flow path with a sample aerosol input, a clean gas input and an output leading to an optical sensor unit. At least one of the inputs has periodic variable flow so that a concentration-modulated gas stream is supplied to the optical sensor unit. The detector output of the sensor unit is processed in synchrony with the concentration modulation to filter out DC components, such as 1 / f noise and parasitic instrument noise.

The present invention provides a laser diode with a current blocking layer without a pn-junction. The laser diode includes a lower cladding layer, an active region and an upper cladding layer on the GaAs substrate in this order. The active region includes first and second regions. The upper cladding layer, which includes a ridge structure, locates on the first region, while, the current blocking region is on the second region of the active region so as to sandwich the ridge structure. The current blocking layer of the invention is made of one of un-doped GaInP and un-doped AlGaInP grown at a relatively low temperature and shows high resistance greater than 105 Ω·cm.

The invention discloses a linear-cavity active Q-switching all-fiber laser. The laser is characterized in that a linear cavity is provided, the output tail of a pumping semiconductor laser is connected with the pumping input port of a fiber beam combiner; the fiber output port of the fiber beam combiner is connected with a high-reflectivity fiber bragg grating; the other terminal of the high-reflectivity fiber bragg grating is welded with gain fibers together; the other terminal of the gain fibers is welded with a low-reflectivity fiber bragg grating formed on polarization-preserving fiber; an adjustable piezoelectric element signal drive circuit is used for driving a piezoelectric element to press fiber in the cavity periodically to modulate the polarization direction of light; the other terminal of the low-reflectivity fiber bragg grating is connected with the input terminal of a fiber isolator; and the output fiber is connected with the output terminal of the fiber isolator. The laser provided by the invention has the advantages of little insertion loss, simplified structure, high repeating frequency of laser pulses, low cost and easiness in industrialization. Large-diameter core double-cladding gain fibers can be used in the laser cavity, so that high-energy high-power laser pulses can be obtained conveniently.

The invention discloses an FPGA-based phase generation carrier demodulation system, and relates to the technical field of optical fiber phase demodulation. The PGC demodulation system uses an FPGA asa signal processor, and can improve the operation rate and demodulation speed of the system. The PGC demodulation system comprises a PGC demodulation module, a data caching module and an asynchronouscommunication module which are connected in sequence. The input to-be-demodulated data is directly input into the data cache module for storage. The PGC demodulation module adopts an improved PGC demodulation algorithm to demodulate the data to be demodulated. A disturbance removing unit is introduced into the PGC demodulation module. The division operation is carried out in the disturbance removal unit to eliminate signals containing alternating current items and modulation depths. Therefore, the output item only has the tangent value of the phase signal. The dependence of the demodulation result on the modulation depth introduced by an external carrier is reduced. The uncertainty of the demodulation result caused by unstable factors such as a light source can also be avoided. The accuracy and the stability of system demodulation are improved.

The invention provides a gas absorption rate online measuring method based on sinusoidal modulation time domain fitting, and belongs to the technical field of tunable diode laser absorption spectrum (TDLAS). The method is characterized in that a sinusoidal signal is used for modulating tunable diode laser current; the laser wavelength sinusoidal modulation is realized; meanwhile, the incident light intensity laser intensity (base line) is enabled to has the clear expression formula; the absorption rate is converted between the frequency domain and the time domain, the clear base line expression formula is combined; the transmission laser intensity is subjected to fitting on the time domain; the synchronous online measurement of the base line and the gas absorption rate is realized. The method has the advantages that the operation is simple and convenient; the problems that the conventional direct absorption method (triangular or sawtooth signal scanning) base line fitting is greatly influenced by artificial factors; the absorption rate measurement precision is low; the time resolution ratio is low; the data processing is completed, and the like. The measurement measure can be provided for spectral line parameter high-precision calibration and gas parameter online monitoring in a complicated industrial field.

The time-sharing control type commodity anti-burglary detection system incldues: D.C. power supply, emitter and receiver, and is characterized by that the interior of D.C. power supply is equipped with a time reference signal generator, and the interior of emitter is equipped with a time-sharing signal generation circuit formed from chip microprocessor integrated circuit and four-stage low-pass filter and wide-band amplification and time-sharing modulation circuit formed from preamplification circuit, wide-band amplifier and analog switch integrated circuit. The interior of receiver is equipped with time-sharing sampling interruption pulse generation circuit formed from waveform conversion circuit and regulation circuit and DSP processing system formed from integrated circuit, exclusion element and crystal oscillation element. Its time-sharing mode can greatly increase capacity of system and raise detection accuracy, under the condition of that its system network capacity is 400 units, its detection distance can be 1.2 m for flexible label and 1.6 m for hard label.

The invention discloses a phase modulation distance measurement and speed measurement coherent laser radar method and device. An output light beam is divided into a local oscillation light beam and anemission light beam through a first beam splitter; the emitted light beam is transmitted to a second beam splitter to be divided into a detection light beam and a reference light beam, the detectionlight beam is emitted to a target and an echo light beam is received; the local oscillation light beam is divided into a first local oscillation light beam and a second local oscillation light beam through a third beam splitter; coherent light mixing is carried out on a local oscillator light beam I and an echo light beam to obtain first sampling data; coherent light mixing is carried out on a local oscillator light beam II and a reference light beam to obtain second sampling data, and a field programmable gate array is used for processing the first sampling data and the second sampling data to obtain an echo phase sequence and a reference phase sequence; and the echo phase sequence and the reference phase sequence are processed to respectively obtain the motion vector speed and distance of the target. According to the invention, the hardware requirement of the laser radar can be reduced, high-resolution and high-precision distance measurement and speed measurement are realized, and the whole system is miniaturized and easy to operate.

The invention relates to a photoelectric marking technology, in particular to an active photoelectric marking method for an MEMS (Micro-electromechanical Systems) infrared light supply array. The invention solves the problem that the conventional photoelectric marking technology is greatly impacted by external environment, cannot meet the requirements of all-weather work, cannot be used for invisible marking under an asymmetrical condition, is low in identifying efficiency, and is small in the range of a reflected light viewing field. The active photoelectric marking method for the MEMS infrared light supply array is achieved by adopting the following steps: a, an infrared light supply array module is manufactured; b, the radiation signals of an FPGA (Field Programmable Gata Array), used for controlling the infrared light supply array module, are simple point infrared spot signals; and c, the radiation signals of the FPGA, used for controlling the infrared light supply array module, are cyclic switching raster graphic signals. The active photoelectric marking method for the MEMS infrared light supply array, provided by the invention, is applicable to the fields of airplane falling guidance, pilotage, routing indication, bridge marking, personnel search and rescue, subaerial space wireless communication, identification and tracking of military targets, and the like.

System and method for amplifying an input signal to generate an output signal. The system includes a current generator, an oscillator, and a comparator. The current generator is configured to receive a first voltage signal, and generate a first current signal based on at least information associated with the first voltage signal and the first reference signal. The oscillator is configured to receive at least the first current signal and a second reference signal, and to generate a second voltage signal based on at least information associated with the first current signal and the second reference signal, the second voltage signal being associated with a modulation frequency. Additionally, the comparator is configured to receive the second voltage signal and a third voltage signal, and to generate a modulation signal related to the modulation frequency based on at least information associated with the second voltage signal and the third voltage signal.

The disclosure concerns an infrared emitter is provided comprising a metalized membrane emitting infrared light in operation. The membrane comprises a two dimensional array of infrared wavelength sized through-holes and to each side a thin metal layer comprising also an array of through-holes. The through-holes are arranged as a two-dimensional periodic array and each of said through-holes have a cross section having a maximum and a minimum dimension of less than any wavelength of the emitted infrared light. The peak wavelength of the emitted infrared light is proportional to the periodicity of the through-holes. At least one of the metal layers is connected to an electrical current source that provides an electrical current that heats at least one of the metal layers so that a narrow bandwidth and highly directive light beam of infrared light is emitted. The membrane is arranged on a membrane support and both are made of a material that resists to temperatures higher than 400°.

The invention relates to an SICM (Scanning Ion Conductance Microscope) amplitude modulation imaging mode scanning device, comprising a signal generator, a patch clamp amplifier, an effective value conversion circuit, a controller, a probe, an XY nano platform, and a Z-direction nano piezoelectric ceramic element, wherein the signal generator, the patch clamp amplifier, the effective value conversion circuit and the controller are connected in sequence. A method provided by the invention comprises the following steps: the signal generator outputs an alternating current signal to the patch clamp amplifier; the compensation capacitance of the patch clamp amplifier is adjusted; and the effective value conversion circuit calculates the effective value of current amplitude, and feeds the effective value of amplitude back to the controller, and the controller controls the height of the probe in real time according to the effective value of amplitude to realize sample scanning. According to the invention, the alternating current amplitude is used as a feedback value, so the defects of a direct-current mode such as direct-current drift and vulnerability to electrical noise are overcome. Higher modulation frequency is achieved compared with the traditional alternating-current mode, and scanning is accelerated.

An optical detector senses the intensity of scattered light reflected by a surface coupled to a vibration source. If the vibration source is operating, the coupled surface vibrates at the same frequency. Incident light reflected by the surface is modulated by the vibration at a hypertemporal frequency. The detector produces a direct electrical current as a temporal function of the detected modulated light intensity. A transimpedance amplifier converts the current into a voltage. A voltage amplifier amplifies the voltage. An analog-to-digital converter converts the amplified voltage into digital signal. A digital signal processor converts the digital signal into a function of power spectral density and frequency using Fourier transform and principle component analyses. The vibration signature of the vibration source, if present, is discerned from a graphical display of the foregoing function.

A device comprising an acoustic detector, one or more thermal sensing elements coupled to the acoustic detector, and a light source. A method comprising directing a beam of light at a wavelength at or near one or more thermal sensing elements, wherein the thermal sensing elements are coupled to an acoustic detector, determining a resonance frequency of the acoustic detector, wherein the acoustic detector is coupled to one or more of the thermal sensing elements, and measuring the response of the acoustic detector to detect optical radiation absorption proximate to or at the surface of one or more thermal sensing elements.

The invention belongs to the technical field of optical polarization state measurement methods and instrument equipment, and particularly relates to a full stokes vector detection device and method based on fast-axis adjustable elasto-optical modulation. The device comprises a 45-degree double-drive symmetric structure elasto-optical modulator, a polarization analyzer, a photoelectric detector, anFPGA control module and a control computer. After sequentially passing the 45-degree double-drive symmetric structure elasto-optical modulator and the polarization analyzer, a to-be-tested light source is detected by the photoelectric detector, the 45-degree double-drive symmetric structure elasto-optical modulator is connected with the FPGA control module through an LC resonance high-voltage driving circuit, the photoelectric detector is connected with the FPGA control module through a signal acquisition unit AD, and the FPGA control module is connected with the control computer. The defectsthat phase modulation methods using liquid crystal phase delayers, electro-optical modulator and the like consume time, and measurement of all full stokes vectors is achieved through multiple times of measurement are overcome, and the single-time measurement time of all the stokes vectors is in the millisecond level.

The invention discloses a microwave signal frequency up-conversion device based on frequency shift feedback laser, which mainly comprises a seed laser, a coupler, an acousto-optic frequency shifter, an optical fiber amplifier, a photoelectric detector and a band-pass filter. In the system, an optical fiber is utilized to construct an annular feedback cavity; a gain is provided through the opticalfiber amplifier to compensate the loss of the annular feedback cavity; repeated laser in the annular feedback cavity is subjected to frequency shift through the acousto-optic frequency shifter, and high-order frequency shift light is generated; the photoelectric detector is used for carrying out photoelectric conversion on the high-order frequency shift light output from a coupler, and a high-frequency microwave signal is generated; and the high-frequency microwave signal is finally output after being filtered through a band-pass filter. The invention has the advantages that all related optical fiber devices are standardized, which are convenient to implement, simple in structure and low in cost, and the invention is realized in an optical mode, the modulation frequency of the acousto-optic frequency shifter is improved, thereby realizing the acquisition of high-frequency microwave signals.

In a method for time-of-flight (ToF) based measurement, a scene is illuminated using a ToF light source modulated at a first modulation frequency FMOD(1). While the light is modulated using FMOD(1), depths are measured to respective surface points within the scene, where the surface points are represented by a plurality of respective pixels. At least one statistical distribution parameter is computed for the depths. A second modulation frequency FMOD(2) higher than FMOD(1) is determined based on the at least one statistical distribution parameter. The depths are then re-measured using FMOD(2) to achieve a higher depth accuracy.

The invention belongs to the field of infrared light sources, and particularly relates to an MEMS infrared light source and a manufacturing method thereof. According to the MEMS infrared light source, a reflecting layer with high reflectivity to infrared radiation is introduced into a heating electrode layer and the back of a supporting material (located in a cavity area of a substrate), so that infrared radiation energy radiated by the heating electrode layer to the cavity part of the substrate through a supporting film is reflected back and is radiated upwards through the heating electrode layer; infrared radiation energy capable of being utilized by the infrared sensor is enhanced, the photoelectric conversion efficiency of the MEMS infrared light source is greatly improved, and the heating power consumption is reduced; meanwhile, the ultrathin (the thickness is not greater than 1 micron) infrared emission layer is introduced, so that the thermal quality of the heating electrode layer is greatly reduced while the high infrared emission capability of the MEMS infrared light source is ensured, the modulation frequency of the MEMS infrared light source is improved, and the heating power consumption is further reduced.

In a method for time-of-flight (ToF) based measurement, a scene is illuminated using a ToF light source modulated at a first modulation frequency FMOD(1). While the light is modulated using FMOD(1), depths are measured to respective surface points within the scene, where the surface points are represented by a plurality of respective pixels. At least one statistical distribution parameter is computed for the depths. A second modulation frequency FMOD(2) higher than FMOD(1) is determined based on the at least one statistical distribution parameter. The depths are then re-measured using FMOD(2) to achieve a higher depth accuracy.