567 results about "Function generator" patented technology

A signal processing system includes a jointly non-linear delta sigma modulator. In one embodiment, the jointly non-linear delta sigma modulator includes a non-linear quantization transfer function, and the output of the delta sigma modulator is defined, at least in part, by a non-linear interrelationship of multiple noise-shaping filter state variables. A look-ahead delta-sigma modulator can be implemented as a noise shaping filter and a function generator. State variables of the noise shaping filter provide the input data from which the function generator determines a quantizer output signal. Latter state variables are more dominant in determining the quantizer output signal. Accordingly, earlier state variables can be approximated to a greater degree than latter state variables without significant compromise in quantization accuracy.

The invention relates to pipeline defect ultrasound guided wave time reversal detection device and method. The method includes the following steps: selecting detecting frequency according to the detected pipeline corresponding free hollow column structure group velocity dispersion curve; inputting the frequency into the arbitrary function generator to generate center frequency used as single sound signal; sending the signal to each passage of exciting/receiving set to transducer unit; exciting longitudinal axis symmetry guided wave modal; sending the reflected signal to the computer and gaining reversal excitation signal by time reversal; repeatedly exciting guided signal to detect. The invention realize space and time focus for guided wave detection, greatly improve detection capability for little defect.

The invention discloses an infrared lock-in heat wave non-destructive detection method based on image sequence processing, which is a new method for realizing infrared lock-in heat wave non-destructive detection by using computer software to process the sequence of infrared images. The method comprises the following implementation steps: using a focal plane infrared heat imager to collect the image sequence of heat wave signals, using a halogen light source modulated by sine law to excite, carrying out digital lock-in processing on heat wave signals and analysis of feature images. When the method is used for non-destructive detection, the focal plane infrared heat imager 5 is fixed on a tripod 16 and connected with a data acquisition card of a computer 11, and infrared lock-in processing software 12 based on the image sequence is used for finishing initialization and image display of the infrared heat imager. The halogen light source 6 is fixed on a special support 7 to ensure that incident light is irradiated in an area to be detected of a sample piece 2 as far as possible, a function generator 14 is connected with a light source power amplifier 13 through a signal wire 15, and light intensity of the halogen light source 6 is controlled to change by the sine law. The incident light of the halogen light source 6 is irradiated to the surface of the sample piece 2 to generate excited heat waves 4. The infrared lock-in processing software 12 based on the image sequence records reflected heat waves 3 or transmitted heat waves 1 generated on the surface of the sample piece 2, a lock-in processing module is used for extracting feature information of the heat wave signals and forming the feature images, an image processing and analyzing module processes and analyzes the heat wave feature images, and inner defect features of the sample piece 2 are extracted, so as to realize fast and accurate non-destructive detection of inner defects and damages of the sample piece 2.

A method for the non-linear ultrasonic online detection of early fatigue damage to a metal material belongs to the field of nondestructive detection. The method comprises the following steps: determining an excitation signal parameter according to the thickness of a tested piece and inputting the parameter to an arbitrary function generator to generate a sound signal; determining a threshold value of an acoustic emission instrument according to the amplitude of a no-load noise signal; performing fatigue loading on the tested piece, continuously detecting an acoustic emission signal in real time with an acoustic emission sensor, amplifying the acoustic emission signal, inputting the acoustic emission signal into the acoustic emission instrument, and judging ring with the acoustic emission instrument when the amplitude of the acoustic emission signal exceeds the preset the threshold value of the acoustic emission instrument; detecting a non-linear ultrasonic signal at equal time interval if the acoustic emission instrument does not display the ring or the times of the continuous ring is not more than an empirical value; and stopping detection if the displayed ring times is more than the empirical value, because fatigue cracks are generated and develop. On the basis of non-linear ultrasonic nondestructive detection, the method of the invention introduces acoustic emission technique, so the method does not make incorrect judgment when detecting the early fatigue damage to the metal material and realizes continuous online detection.

The invention discloses a quartz tuning fork strengthened photoacoustic spectroscopy gas sensor based on an acoustic resonator. The gas sensor comprises a laser (1), a focusing lens (5), a tubular resonator, a quartz tuning fork (11), a function generator (15) electrically connected with the laser (1) and a lock-in amplifier (14) electrically connected with the quartz tuning fork (11), wherein the focusing lens (5) and the tubular resonator are arranged on an optical path (2) of the laser (1); the function generator (15) is electrically connected with the lock-in amplifier (14); the tubular resonator is the acoustic resonator (9) with a slit (91) in the middle; the length of the acoustic resonator is not more than 10mm, the external diameter is not more than 1mm and the internal diameter is not more than 0.6mm; the width of the slit (91) is not more than 0.2mm and the length is not more than the internal diameter of the acoustic resonator (9); prongs (111) of the quartz tuning fork (11) are positioned on the slit (91) and the distances between the prongs (111) and the slit (91) are not less than 0.001mm. The gas sensor has simple structure, small volume and strong anti-jamming property, works stably, is convenient to adjust and use and can be extensively used for detecting the components or contents of the gases.

Logic design apparatus and method provides serial multiplexer chains in a programmable logic fabric, each element in the chain either selects output of block, or passes output from earlier element of the chain. Select line is a decoder structure or output from configurable function generator that is configured at power-on to create correct selection. Using such structure, larger multiplexer, including priority multiplexers, tristate buses or larger look-up tables (LUTs) can be created. These novel structures can implement priority, non-priority or tristate multiplexers.

The present invention relates to the technical field of laser spectrum detection and gas detection, and in particular relates to a two quantum cascade laser spectrum-based multicomponent gas simultaneous detection device and method. An arbitrary waveform function generator outputs a periodic signal which only superposes high-frequency modulation signals in any half period to be used as a laser current signal, a room temperature continuous mode mid-infrared quantum cascade laser is driven by a current control unit, the laser emits a laser signal, the laser signal passes sequentially through a focusing collimating three-dimensional adjustment system, a first mirror, a sample absorption pool and a off-axis parabolic mirror to be reflected to a first detector, the first detector passes the laser signal through a data acquisition unit to convert into an electrical signal and transmit to a computer, and information of the gas to be measured can be obtained by analysis and processing of the electrical signal by the computer. The devices simultaneously utilizes two spectrums for gas detection, and has the advantages of high detection sensitivity, high detection accuracy, no need of external standard gas calibration, simple optical path adjustment, fast response, and stability, and the like.

The vertical dual-shaft four-cylinder electrohydraulic servo testing machine comprises: a hydraulic pressure drive for dual-direction stress filed, a four-cylinder drive fit to any loading path, a differential close-loop servo system, a function generator fit to different waves, a position transfer device fit to assemble the test piece, a guide plate and linear rail to ensure co-shaft and avoid bending. This invention is very convenient.

The invention provides a system and a method for detecting CO gas based on a quartz tuning fork enhanced photoacoustic spectrometry technology, relates to a system and a method for detecting the CO gas and aims at solving the problem of low detection accuracy of the existing CO gas photoacoustic spectrometry detection technology. A data processing module transmits a current control signal to a laser device controller via a function generator, and meanwhile, transmits a temperature control parameter to the laser device controller; the laser device controller drives a laser device to emit near infrared laser which is incident into a gas chamber after being collimated and focused; the gas absorbs optical energy so that the optical energy is converted into heat energy and further converted into an acoustic pressure signal; a quartz tuning fork mounted in the gas chamber converts an acoustic signal into an electric signal; the electric signal of the quartz tuning fork is converted and amplified and then input into the measurement channel input end of a phase-locked amplifier; the phase-locked amplifier inverts the concentration of the CO gas to be detected by performing secondary harmonic detection in combination with the reference signal of the function generator. The system and the method for detecting the CO gas based on the quartz tuning fork enhanced photoacoustic spectrometry technology are applicable to CO gas detection.

The present invention relates to processes, systems, and apparatuses for transcieral delivery of pharmaceutical formulations to the eye using ultrasound. In one embodiment, a transducer is placed in contact with a coupling media contained in a coupling well in contact with the sclera. When the transducer is placed at a desired standoff distance, ultrasonic waves are emitted to increase tissue porosity and transport a pharmaceutical formulation through the scleral tissue and into the eye. In another embodiment, a function generator is coupled to an amplifier, a matching network, and a transducer configured to maximize the cavitation effect of ultrasonic waves for drug delivery across a sclera.

A small-sized, high-functionality optical pulse compressor capable of generating a low-power, high-repetition-frequency ultrashort pulse train used for ultralast optical communication and photometry, and a simple-structure optical function generator for realizing an arbitrary time waveform. The optical pulse compressor comprises and optical Fourier transform device (F) having an optical phase modulator (9) driven by the repetition-frequency of an input optical pulse train and a dispersive medium (8), for converting the shape of an input optical pulse frequency spectrum into its time waveform, and an optical filter (3) inserted ahead of the optical Fourier transform device (F), for reducing the spectrum width of an input optical pulse, wherein the optical Fourier transform device (F) converts a small-spectrum-width optical pulse output from the optical function generator generates an optical pulse. The optical function generator generates an optical pulse having an arbitrary time waveform by reproducing, as it is, a spectrum waveform-shaped arbitrarily by an optical filter on a time-axis by tch optical Fourier transform device (F).

The invention provides a monitoring method for blade crack of a wind driven generator. The monitoring method mainly includes setup of a piezoelectric ceramic fan crack damage health monitoring system and a fan blade crack damage assessment method. The piezoelectric ceramic fan crack damage health monitoring system mainly comprises piezoelectric ceramic pieces, a function generator and an oscilloscope. The working principle is an active surveillance technology based on a piezoelectric ceramic wave method, and the working procedures include utilizing the function generator to emit sine sweeping-frequency signals and the oscilloscope is used for real-time display and storage for received detection signals. The fan blade crack damage assessment method includes utilizing Fourier spectrum analysis to calculate two defined damage indexes based on wavelet packet analysis, successfully monitoring crack areas and performing verification through time reversal. The monitoring method is easy to operate, and the identification effect of blade crack of the wind driven generator is remarkable. The monitoring method is general, and can be applied to damage monitoring of composite materials similar to fan blades.

An inductive coupled power transmission circuit has a rotating transformer, including an AC voltage supply for feeding an AC voltage via a series capacitor into the primary winding of said rotating transformer and a load being coupled to the secondary winding of said rotating transformer. The AC voltage supply includes a line rectifier for receiving AC voltage from a power line and generating a DC voltage. This is fed into a DC/DC converter for converting the DC voltage from the line rectifier into a controlled intermediate DC voltage. An AC generator generates an AC voltage from the intermediate DC voltage and feeds this via a matching transformer into the primary winding of the rotating transformer. A measuring circuit measures voltages and/or currents within the AC voltage supply and a function generator estimates voltage and/or current values at the load based on the measured values and controls the DC/DC converter and/or the AC generator based on the estimated values.

The present invention includes an apparatus and corresponding method for fluid flow control in microfluidic applications. A microchamber, filled with a fluid, is in fluid contact with a flexible plate. A transducer is acoustically coupled to the flexible plate. A function generator outputs a signal to excite the transducer, which in turn induces drumhead vibration of the flexible plate, creating a flow pattern within the fluid filled microchamber.

In thermography apparatus, a lamp 102 is modulated sinusoidally and a camera 106 captures thermal images at the modulated frequency, but delayed by an adjustable preset delay. A signal delay box 107 is connected between a sinusoidal modulation signal function generator 104 and the camera 106. The delay box introduces a delay to the function generator signal so that the thermal image is captured after a period of time, resulting in an enhanced image.

The invention discloses a Fourier transform chip spectrometer based on integrated light technique, comprising an integrated optical waveguide chip having electro-optic modulation function. Light from a light source enters the integrated optical waveguide chip through a fiber transmission coupler, and waveguide light from the chip enters an optical waveguide interferometer through a sensitive window interval. The interferometer outputs signals to a photoelectric detector. A voltage function generator is used for applying voltages varying with time between two modulated electrodes of the optical waveguide interferometer, the photoelectric detector is used for real-time measuring the change of the signal strength of the interferometer varying with the modulated voltage, and a signal processing chip connected with the photoelectric detector and the voltage function generator at same time is used for rapidly processing Fourier transform on the signals of the interferometer to obtain an incident light spectrum. The Fourier transform chip spectrometer provided by the invention can determine visible-infrared light absorbing spectra of solids, liquid, even monomolecular adsorption layers in the sensitive window, and determine fluorescence spectra of fluorescent substances in the sensitive window, with the advantages of strong anti-interference capability, and is suitable for rapid on-site quantitative determination.