73results about How to "Demodulation speed is fast" patented technology

The invention relates to an allfiber type long period fiber grating solution multi-parameter sensing system. Broadband light source output light enters the input end of a 2*2 fiber coupler by a compound long period fiber grating; one path of output light of the 2*2 fiber coupler enters a first fiber Bragg grating; the other path of the output light enters a second fiber Bragg grating by a fiber isolator; the reflected light of the two fiber Bragg gratings is collected by a data capture card after entering a photoelectric conversion module and a signal amplifier; and a computer carries out data processing and real-time measurement result display. In the multi-parameter sensing system, the compound long period fiber grating serves as the sensitive elements of a plurality of parameters, matched fiber Bragg gratings serve as signal demodulation elements to realize the allfiber type multi-parameter sensing system. The allfiber type long period fiber grating solution multi-parameter sensingsystem has the advantages of electromagnetic interference, allfiber type measurement and the like and can be remotely monitored.

The invention relates to a low-consumption demodulation method for an FSK signal in wireless charging equipment. The method is characterized in that a signal on a receiving coil is sent to the input end of a demodulation chip comparator, and comprises the following steps of: (1) sampling an output value of the comparator and acquiring the number of sampled points in a period; (2) demodulating the signal according to the number of the sampled points in the period; (3) synthesizing a complete data frame according to a demodulated result; and (4) verifying and outputting the complete data frame. In the low-consumption demodulation method which adopts the above steps and is used for the FSK signal in the wireless charging equipment, a complex analog circuit is not required, the maximum frequency required by a digital circuit in the method is only 2 MHz, , only a simple addition operation is performed under the frequency, and the main operating frequency is 210 KHz or below; and compared with a conventional FSK decoding method, the method is more suitable for the FSK signal according to the QI standard, the cost is low, the demodulation speed is high, debugging is convenient and the precision is high.

The invention discloses a fiber bragg grating track sensing system based on an optical code division multiple access technique. An encoding optical pulse emitted by a broadband light source under the control of a control and analysis unit enters a plurality of sensing fiber bragg grating arrays arranged along a track through an optical isolation unit, the reflected light of the fiber bragg grating arrays enters a modulating circuit in an electrical signal mode for I-V conversion and voltage amplification after entering a photoelectric receiving unit through an optical filter, and a digital-to-analog converter samples the amplified voltage signals to convert the voltage signals to digital signals and then transmitting the digital signals to the control and analysis unit for analysis so that the modulation result of the measured physical quantity is obtained; and the used encoding sequence and the length and the bit time slots thereof are stored by the control and analysis unit. Compared with the sensing system using the traditional fiber bragg grating network multiplexing technique, the invention has the advantages of simple structure, flexible networking, greatly increased multiplexing quantity, high modulating speed and the like and is especially suitable for the quasi-distribution type measurement of a plurality of physical quantities in the large range of track traffic line.

The invention relates to a PMA standard targeted wireless power charging device's frequency modulation signal demodulating method, comprising: 1) reading wire coil signals; sampling the wire coil signals; and counting the cycles; 2) extracting the frequency changes based on the change of the counted cycles; 3) determining and outputting data according to the frequency changes and the duration of the frequencies; and 4) splicing and outputting the data. With the method, the demodulation part does not require a complicated simulation circuit and the highest frequency required by its digital circuit part is only 4MHz at which only simple adding operation is performed. The main working frequency is under 236KMz. Compared with the current FSK decoding method, the method can be more consistent with PMA standard demodulation signals. With a lower cost yet higher demodulation speed, the method is also convenient to debug and does not have requirement on the fixing of Fop or not. With high precision to be achieved, the method can be applied more widely.

The invention discloses a signal processing method for a wireless charging system, a receiving terminal and a storage medium. The method comprises the steps of transmitting a signal on a receiving coil to an input end of a comparator of a demodulation chip through the receiving terminal, sampling an output value of the comparator and obtaining the number of sampling points in one period; demodulating the signal according to the number of the sampling points in one period; synthesizing a complete data frame according to the demodulation result of the signal; and verifying and outputting the complete data frame. According to the signal processing method, electric energy is transmitted by using a frequency band, and the signal processing method is more suitable for an FSK signal of a QI standard, is low in cost, high in demodulation speed, easy to debug and relatively high in accuracy, and is free of a requirement for whether a communication carrier frequency is fixed or not.

The invention discloses a double-edge cross demodulation and nonlinear correction method of a piezoelectric ceramic type tunable wavelength filter. The double-edge cross demodulation and nonlinear correction method comprises the following steps of making light of a wide-spectrum light source enter an optical splitter through the piezoelectric ceramic type tunable wavelength filter, wherein the light is divided to two paths by the optical splitter, the first-path light penetrates through an optical grid generator and is collected as a standard spectrum, and the second-path light is directed collected as a to-be-measured spectrum; and performing grouped cross demodulation and correction on the collected data. The corrected demodulation result can eliminate the function of a piezoelectric ceramic hysteresis effect and furthermore improves demodulation efficiency.

The invention discloses a fast Gaussian fitting method applied to fiber Bragg grating wavelength demodulation. The method comprises steps: 1, according to an acquired reflectance spectral data interval, a digital interval for logarithmic operation is determined, and a proper Hash table is built according to resources inside the system; 2, advanced operation is carried out on a fixed coefficient process decomposed through theoretical analysis and formula conversion, and an operation result is stored in a dependent variable for later use; 3, a look-up table method is adopted to calculating the natural logarithm of a sampled spectral value; and 4, a fitting process, that is, a fiber grating demodulation process, is carried out. The method can effectively solve the problem of limitations on the demodulation speed by the traditional Gaussian fitting algorithm and greatly improves the fiber grating demodulation speed on the premise of not reducing the demodulation precision and the demodulation range.

The invention discloses a fiber grating digital demodulation method and system based on the autocorrelation principle. The invention solves the problems of present fiber grating sensor system demodulation technology of low measuring precision, poor real-time performance, insufficient reuse ability, high price, unsatisfied engineering practical needs, etc. The invention has the advantages of high measuring precision, fast scanning speed, good real-time performance, strong reuse ability, high performance-price ratio, strong utility, etc. The structure of the invention includes a light source and at least a fiber grating sensor. Through a coupling device, the light source is connected with the fiber grating sensors which are successively linked in series. At the same time, the coupling device also can be connected with a tunable filter, which is linked with a photoelectric detector. The photoelectric detector is successively connected with a preamplifier and a digital-analog converter. The digital-analog converter is connected with the input terminal of a digital controller. The output terminal of the digital controller is connected with the controlling input terminal of the tunable filter via an electromechanical controller and an electromechanical modulation system in turn.

The invention relates to an optical fiber temperature and pressure composite sensor, in particular to an optical fiber temperature and pressure composite sensor which can be used for simultaneous measurement of the temperature, absolute pressure or relative pressure of liquid and gas, and belongs to the field of optical fiber sensing technology. The sensor realizes simultaneous measurement of thetemperature and pressure through a simple two-layer structure, a transmission optical fiber with collimated microlenses on its end faces is used to enhance the signal quality of the sensor, two spectral analysis modules containing optical wedges with different thicknesses are used to demodulate a pressure sensing cavity length and a temperature sensing cavity length respectively, interference signals of the two cavities are separated through the one-to-one correspondence between the wedge thicknesses and the cavity lengths, in this way, the data processing steps are simplified, the demodulation speed is increased, and the measurement of dynamic pressure and temperature signals facilitated.

The invention discloses a polarization-interference-based optical path difference measuring device and method of a Mach-Zehnder interferometer. The measuring device is composed of a light source (1),a polarizer (2), first to sixth polarization-maintaining fibers (3) (5) (6) (7) (8) and (10), first and second polarization-maintaining couplers (4) and (9), a Wollaston prism (11), first and second photodetectors (12) and (13), a digital acquisition card (14) and a processing system (15). Light outputted by the light source (1) is polarized by the fiber polarizer (2); the light is split into twobeams of polarized light by the polarization-maintaining coupler (4); the two beams of polarized light enters the two arts, that is, the second and third polarization-maintaining fibers (5) and (6), of the Mach-Zehnder interferometer respectively, wherein the output polarization directions correspond to two groups of polarized light in quick axis and slow axis directions of the fourth and fifth polarization-maintaining fibers (7) and (8); the phase difference of the two groups of polarized light is pai/2 by adjusting the lengths of the fourth and fifth polarization-maintaining fibers (7); anda phase is calculated by using a quadrature phase demodulation method.

The invention relates to a sensing demodulating system for an optical chirped-grating. The system is composed of two parts: a sensing part and a demodulation part; wherein the sensing principle of the system is as follows: when external physical parameters change, envelope area of a reflection spectrum used for sensing optical chirped-grating changes accordingly; the demodulation part is strength type demodulating equipment which is mainly composed of a broadband light source, a demodulation light path, an O/E and signal processing circuit. Optical signals are emitted from the broadband light source, the sensed grating is partially reflected back to the demodulating equipment, the reflected optical signals are divided into two paths through a branching unit with one path of the optical signals directly transmitted to a photoelectric detector and the other path of the optical signals reflected through a reference grating before being received by another photoelectric detector. The last two paths of electrical signals are processed by the signal processing circuit to obtain output result of the system; the result output is free from influence of the light source and light power fluctuation of a transmission light path, thus achieving the purpose of improving system accuracy. In addition, the invention has the characteristics of simple structure, low cost and applicability to both dynamic and static measurement.

The invention relates to a multifunctional fiber grating sensing system. Output light of a broadband light source enters a beam splitter after being modulated by a long-period fiber gating, and the split beams respectively enter an optical coupler, an optical isolator and a photo detector. The emergent light from the coupler enters a first fiber Bragg grating; the emergent light from the optical isolator enters another beam splitter, and the emergent light from the beam splitter is divided into two parts, the first part enters a second fiber Bragg grating, and the second part enters a third fiber Bragg grating through a second coupler; the light reflected/transmitted by the three fiber Bragg gratings is received by a corresponding photo detector, and all output signals of the photo detectors are acquired by a data acquisition card and processed by a computer. The fiber grating sensing system has the function of measuring a plurality of different parameters, the function of automatically eliminating measurement errors caused by fluctuation of output power of the light source, and the function of automatically eliminating the measurement errors caused by change of the ambient temperature.

The invention provides a thermal stability sensing demodulation system and method using a narrowband dual phase shift fiber bragg grating. The system comprises a wavelength tunable laser, a polarization controller, a phase modulator, a three-port optical circulator, a dual-phase-shift fiber bragg grating, an optical fiber amplifier, a photoelectric detector, a microwave amplifier and a microwave coupler which are mutually connected. The first port of the optical circulator is connected to the output port of the phase modulator. The second port of the optical circulator is connected to the dual-phase-shift fiber bragg grating. The third port of the optical circulator is connected to the optical fiber amplifier. The input end of the microwave coupler is connected to the output end of the microwave amplifier. The first output end of the microwave coupler is connected to the radio frequency end of the phase modulator. The second output end of the microwave coupler is connected to an electric spectrometer.

The disclosure relates to a demodulator including a pinned photodiode, at least one storage node, at least one transfer gate connected between the storage node and the pinned photodiode. The pinned photodiode includes a p-doped epitaxial semiconductor layer, a n-doped semiconductor region formed within the epitaxial semiconductor layer and creating therewith a lower junction and at least one lateral junction substantially perpendicular to the lower junction, a p+ pinning layer formed on top of said semiconductor region. The demodulator further includes a generating unit configured to generateminority and majority carriers at said lateral junction and to form a lateral photodiode.

The invention discloses a high-speed large-dynamic-range fiber bragg grating demodulation system, which comprises a broadband light source, a three-port optical fiber circulator, an optical fiber coupler with a splitting ratio of 50:50, a first narrow-band filter, a second narrow-band filter, a first photoelectric detector, a second photoelectric detector and a data acquisition and processing unit, wherein the output spectrum of the broadband light source is in a Gaussian type with a linear long hypotenuse, the spectrum has unimodality, high-speed demodulation of the fiber bragg grating is carried out by utilizing left and right approximately linear long hypotenuses in the output spectrum of the broadband light source, and the wavelength change of the grating is converted into the change of the power of reflected light output by the grating. The invention further provides a method for demodulating a fiber bragg grating sensor by using the high-speed large-dynamic-range fiber bragg grating demodulation system. The demodulation system has the advantages of high demodulation speed, wide measurement range, high demodulation precision, small limitation on grating wavelength and the like, and is suitable for testing transient large variables such as explosive shock wave pressure.

The invention discloses a fiber bragg grating wavelength demodulator which comprises a broadband flat light source, a circulator, a fiber bragg grating, a beam splitter, a plurality of narrow-band transmission optical filters, a photodiode, a trans-impedance amplifier and a differential amplification circuit. The inclination angles of two adjacent narrow-band transmission optical filters are different, and the narrow-band transmission optical filters and the corresponding amplification and differential circuits form wavelength demodulation channels. The narrow-band transmission optical filters with different preset angles are utilized to realize that the change relation of transmission light intensity along with the increase of wavelength is just opposite, a photodiode is utilized to convert an optical signal into a current signal, and a trans-impedance amplifier is utilized to convert the current signal into a voltage signal and amplify the voltage signal; and the two voltage signals are differentiated and amplified by a differential amplifier to obtain the relationship between the differential signal and the central wavelength of the FBG. Compared with other FBG wavelength demodulation devices, the wavelength demodulation device has the advantages that the structure is simple, the demodulation speed is high, the demodulation speed is about 100 MHz, and the demodulation precision is about +/-5 pm.

An ultra-weak fiber grating wavelength demodulation module comprises a shell, a laser pulse generator, an optical line unit and an embedded board card are arranged in the shell, the embedded board card is respectively connected with the laser pulse generator and the optical line unit, and the laser pulse generator is connected with the optical line unit. And the laser pulse generator is used for generating laser pulses with repeatedly changed wavelengths. And the optical circuit unit is used for amplifying and outputting the laser pulse, receiving an optical signal returned by the measured object, completing photoelectric conversion and then outputting the optical signal. The embedded board card is used for performing instruction and parameter setting on the laser pulse generator and configuring the optical circuit unit; and the embedded board card is used for grating positioning and wavelength real-time analysis, and outputting the wavelength and position information of the ultra-weak grating. The pulse type wavelength scanning laser is adopted to replace a light source and a light modulator, and an optical circuit is integrally designed, so that the system structure is simplified, the power consumption and the size of the demodulator are greatly reduced, and the demodulation speed is improved.