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

The invention discloses a system for sensing a VCSEL (Vertical Cavity Surface Emitting Laser) based ultrahigh-speed FBG (Fiber Bragg Grating). The system comprises a VCSEL laser light source, a sensing probe and a photovoltaic conversion module, wherein the sensing probe comprises an inclined FBG and a cladding-fiber core energy re-coupling structure; the photovoltaic conversion module comprises a vibration information demodulating part and an attenuation reference obtaining part; an external data processing device gives a normalized output of the system. The realization method comprises the steps of: outputting high-speed periodically modulated laser to an optical fiber coupler by the LCSEL laser light source, wherein one path of optical signals are subjected to attenuation of an attenuator and photovoltaic conversion to obtain reference electric signals, and the other path of optical signals enters into an optical fiber probe to obtain reflected light signals including environment vibration information and then is subjected to the photovoltaic conversion to obtain vibration electric signals; and dividing the reference electric signals by the vibration electric signals to obtain the normalized output of the sensing system. The system and method for sensing VCSEL based ultrahigh-speed FBG, disclosed by the invention, have the advantages of ultrahigh-speed (higher than MHz) and high-sensitivity (superior to 15 dB) vibration sensing, high system integration level, low cost (no need of filtering), normalized output for removing temperature change influence and high stability.

The invention relates to a quasi-distributed composite structure strain and temperature detection system. Light output by a broadband light source passes through an optical fiber isolator and enters the input end of a 2*2 optical fiber coupler; the light output by the 2*2 optical fiber coupler enters the input end of a 1*m optical switch; the light output by the 1*m optical switch enters an m*n network type optical fiber grating sensing head; the light reflected by the m*n network type optical fiber grating sensing head sequentially passes through the 1*m optical switch and the 2*2 optical fiber coupler and further enters the input end of an optical fiber adjustable F-P (Fabry-Perot) filter; and the light output by the optical fiber adjustable F-P filter sequentially passes through a photoelectric conversion module, a signal amplifier, a data acquisition card and a computer, and the computer is used for processing and displaying data. The system utilizes the optical fiber adjustable F-P filter to realize wavelength demodulation of signal light reflected by all sensing optical fiber gratings, and has the advantages of anti-electromagnetic interference effect, all-optical fiber type measurement, a large number of multiplexing measuring points, remote monitoring, non-destructive measurement and the like.

The invention relates to a high-speed demodulation device and method based on fiber fabry-perot cavity and fiber grating combined measurement. The high-speed demodulation device comprises a power supply module, a 3dB coupler, a circulator, a sensing unit and a demodulation unit. The high-speed demodulation method comprises that the relation among the demodulation error amount, the temperature variation and the pressure / strain variation of a fiber grating is obtained via calibration, and relation among the length variation of a fiber fabry-perot cavity, the temperature variation and the pressure / strain variation is obtained via calibration; the length variation of the fiber fabry-perot cavity and the drift amount of the wavelength of a reflection center of the fiber grating are modulated; and the temperature variation and the pressure / strain variation are solved. Compared with the prior art, double parameters can be measured via rapid demodulation on the basis of fiber fabry-perot cavity and fiber grating sensing, influence of fiber fabry-perot interference spectrum on temperature measurement caused by fiber grating modulation is compensated, and the cost is low.

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 provides a parallel interpolation bit synchronization system in all-digital demodulation and a synchronized method thereof. The method comprises the following steps: (1) delaying two paths of input parallel sampling data K1 and K2 respectively for three clock cycles, and obtaining K1_d1, K1_d2, K1_d3 and K2_d1, K2_d2 and K2_d3; (2) respectively carrying out interpolation processing to the above sampling data and uk; (3) delaying indicating effective signals to the time when the above interpolation processing obtains results, carrying out extraction to the interpolation processing results in the step (2) according to the indicating effective signals, obtaining maximum points of symbols and traversing points of symbols and outputting the maximum points of the symbols; (4) calculating timing errors according to the maximum points of symbols and traversing points of symbols obtained in the step (3), carrying out noise filtration on the timing errors and obtaining NCO control signals after adjusting amplitude processing; and (5) determining the interval uk of the indicating effective signals and the maximum points of symbols with the former sampling point, entering next clock cycle and starting execution from the step (1).

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 an online real-time optical fiber grating fire monitoring system which is implemented based on the coarse wavelength division multiplexing (CWDM) demodulation technique, the optical time-domain analysis technique and the optical fiber grating temperature measurement technique. The system comprises an optical fiber circulator, wherein the input terminal of an optical fiber circulator is connected with a laser diode with a tail fiber, and the output terminals of the optical fiber circulator are connected in sequence with a coarse wavelength division multiplex demodulator; a photoelectric detector connected with a digital signal processor; a temperature-detecting optical cable connected with the other port of the optical fiber circulator; optical fiber grating temperature-sensitive fire detectors numbering n of the same wavelength connected to the temperature-detecting optical cable; and a display device or an alarm connected with the signal output terminal of the digital signal processor. N is a positive integer. The fire monitoring system has the advantages of low cost, high resolution and high demodulation speed and is better in performance-price-ratio than the prior fire-control temperature-sensitive cables and other temperature-sensitive optical cables.

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 provides a high transmission rate and bandwidth utilization rate of MIMO Multi-h CPM wireless communication method and relates to the wireless communication field. The problems that CPM demodulation is low in demodulation speed, low in real-time performance and high in receiver hardware cost by the existing wireless communication method are solved. The high transmission rate and bandwidth utilization rate of MIMO Multi-h CPM wireless communication method comprises coding baseband signal bit data flow to obtain coding signals; performing serial-parallel conversion on the obtained coding signals to obtain Nt routes of symbolic data flow; performing Multi-h CPM modulation on every route of symbolic data flow to obtain Nt routes of M system modulation signals s (t, alpha) to be sent; transmitting the obtained Nt routes of modulation signals to Nt*Nr fading channels through Nr transmitting antennas; receiving the Nt routes of modulation signals through Nr receiving antennas; loading thermal noise to the Nt routes of modulation signals; performing PAM (Pulse Amplitude Modulation) decomposition based optimal detection on the signals after the thermal noise loading; outputting the Nt routes of signals after the PAM decomposition based optimal detection after parallel-serial conversion. The high transmission rate and bandwidth utilization rate of MIMO Multi-h CPM wireless communication method is suitable for wireless communication.

The invention discloses an all-fiber Fourier transform Raman spectrometer, which includes transmission fibers, a laser, a fiber Raman probe, an all-fiber dual-beam interference system, and a photomultiplier. The laser, the fiber Raman probe, the all-fiber dual-beam interference system and the photomultiplier are associated with each other by means of the transmission fibers. The laser is irradiated on a sample through the fiber Raman probe and forms Raman diffusion light. The Raman diffusion light is collected by the fiber Raman probe and enters the all-fiber dual-beam interference system, and therefore two paths of interference light are formed. One light path of the two paths of interference light is modulated by a phase modulator in the all-fiber dual-beam interference system, and the modulated interference light is output to the photomultiplier and converted into an electric signal. Fourier transform of Raman spectrum is achieved and then spectrum demodulation is realized by means of the all-fiber dual-beam interference system, and dual-beam light path difference modulation is performed by an all-fiber phase modulator. The all-fiber Fourier transform Raman spectrometer, becoming miniature, is high in resolution, high in signal to noise ratio, wide in spectrum scope and low in cost.

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 relates to a rapid search method of a resonant frequency of a surface acoustic wave resonator (SAWR). Excitation signals synthesized by fixed low-frequency signals and size-adjustable local oscillator signals are emitted for exciting the SAWR; then whether received signals are effective excitation signal of the SAWR is determined, if not, the excitation signals are adjusted for performing excitation again, and if so, down-conversion processing is performed, and a period of echo signals is obtained and stored through searching for signal zero-crossing points; and finally, a maximum value of the period of the echo signals corresponding to all effective excitation is sought, excitation signals corresponding to maximum period signals are obtained, frequency estimation is performed on the echo signals generated when the excitation signals act on the resonator, and a current resonant frequency estimation value of the SAWR is obtained. According to the invention, the algorithm does not need frequency estimation in a scanning process, the whole scanning process is completed in a time domain, signal phase influences are eliminated, the scanning speed of the SAWR is effectively accelerated, and the demodulation speed of an SAW sensor is improved.

The present invention discloses a method for demodulation in Multi-user Reusing One Slot operation and a system thereof, belonging to the field of mobile communication. The method comprises the following steps: obtaining a first signal-interference-noise ratio according to a strong signal of a channel which has a greater impulse response on wireless channels; reconstructing the strong signal; subtracting the signal which is obtained by reconstructing the strong signal from the resultant signal received on the wireless channels to obtain a weak signal; obtaining a second signal-interference-noise ratio according to the weak signal; determining whether the second signal-interference-noise ratio is greater than a first iteration threshold; reconstructing the weak signal and updating the first iteration threshold to be the second signal-interference-noise ratio if the second signal-interference-noise ratio is greater than a first iteration threshold; otherwise, ending; obtaining a strong signal according to the signal obtained by reconstructing the weak signal; and reconstructing the obtained strong signal again. According to the invention, demodulation performance of uplinks of communication system can be improved significantly.

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 invention provides a random access response receiving method, a random access response sending method, a terminal and network equipment, and relates to the technical field of communication, the random access response receiving method comprises the following steps: obtaining a receiving configuration parameter of a random access response corresponding to random access; Receiving the random access response according to the receiving configuration parameter; Wherein the random access response format adopted by the random access is different from the random access response format adopted by the random access of other scenes. According to the scheme, it is guaranteed that the terminal can receive the random access response of the terminal in a targeted mode, the demodulation speed of the terminal is increased, and power consumption of the terminal is reduced.

The invention discloses a digital coding FSK track circuit information demodulation method based on frequency spectrum analysis. The method comprises the steps of preprocessing digital coding FSK track circuit information through a front-end circuit; performing spectrum analysis on the preprocessed digital coding FSK track circuit information based on discrete Fourier transform; demodulating all basic frequency point information, verifying demodulated code element information flow, carrying out frequency spectrum amplitude calculation on effective frame information in the demodulated code element information flow, comparing upper and lower edge frequency amplitudes of corresponding basic frequency points, defining and outputting code element values corresponding to code elements accordingto a track circuit BFSK, and recording the code element values.

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.