173 results about "Discrete spectrum" patented technology

A solar energy conversion package includes a photovoltaic (PV) cell, a thermionic or thermoelectric conversion unit and a thermal heating system. Solar radiation is concentrated by a lens or reflector and directed to the PV cell for electrical power conversion. A water circulation system maintains the PV cell at working temperatures. The thermionic or thermoelectric conversion cell is coupled between these cells in the thermal path to generate additional power. Additional efficiencies may be gained by partitioning the solar radiation with prisms or wavelength specific filters or reflective coatings into discrete spectrum segments optimized for each conversion unit for maximizing efficiency of electrical energy conversion and equipment design. Integrating all three of these conversion techniques produces a synergistic system that exceeds the performance conventional solar conversion systems.

The system comprises: a baseband signal sequence generator for generating baseband signal sequence; a power control unit for respectively multiplying the baseband signal sequences by different coefficients in order to make the power of discrete spectrum line corresponding to one part of the baseband signal sequence to be as zero, and make the discrete spectrum line corresponding to another part of the discrete spectrum to be as single-frequency pilot frequency; a multiplexing unit for multiplexing the baseband signal sequence outputted from power control unit into one route of data transmitted to the random frequency hopping unit; a random frequency hopping unit for randomly changing the frequency spectrum position of single-frequency pilot frequency in synchronous channel of each frame; and a synchronous pilot frequency generating unit for generating synchronous pilot frequency sequence according to the data after random frequency hopping.

A hybrid light source comprises a discrete-spectrum lamp (for example, a fluorescent lamp) and a continuous-spectrum lamp (for example, a halogen lamp). A control circuit individually controls the amount of power delivered to the discrete-spectrum lamp and the continuous-spectrum lamp in response to a phase-controlled voltage generated by a connected dimmer switch, such that a total light output of the hybrid light source ranges throughout a dimming range. The discrete-spectrum lamp is turned off and the continuous-spectrum lamp produces all of the total light intensity of the hybrid light source when the total light intensity is below a transition intensity. The continuous-spectrum lamp is driven by a continuous-spectrum lamp drive circuit, which is operable to conduct a charging current of a power supply of the dimmer switch and to provide a path for enough current to flow through the hybrid light source, such that the magnitude of the current exceeds rated latching and holding currents of a thyristor of the dimmer.

A hybrid light source comprises a discrete-spectrum lamp (for example, a fluorescent lamp) and a continuous-spectrum lamp (for example, a halogen lamp). A control circuit individually controls the amount of power delivered to the discrete-spectrum lamp and the continuous-spectrum lamp in response to a phase-controlled voltage generated by a connected dimmer switch, such that a total light output of the hybrid light source ranges throughout a dimming range. The discrete-spectrum lamp is turned off and the continuous-spectrum lamp produces all of the total light intensity of the hybrid light source when the total light intensity is below a transition intensity. The continuous-spectrum lamp is driven by a continuous-spectrum lamp drive circuit, which is operable to conduct a charging current of a power supply of the dimmer switch and to provide a path for enough current to flow through the hybrid light source, such that the magnitude of the current exceeds rated latching and holding currents of a thyristor of the dimmer.

The invention discloses a harmonic analysis method based on Kaiser self-convolution window dual-spectrum line interpolation FFT (Fast Fourier Transform) and a device thereof. The method comprises the following steps of sampling a signal: sampling a time-domain continuous signal, and discretizing to obtain an infinitely long discrete sequence; windowing a four-order Kaiser self-convolution window function: performing four-order Kaiser self-convolution window operation on the infinitely long discrete sequence; performing N-point FFT on a windowed and truncated signal to obtain the discrete spectrum of the signal; determining the peak parameter of the discrete spectrum: searching the local spectrum peak of each integer harmonic frequency around the integer harmonic frequency; and calculating a harmonic parameter: solving a coefficient alpha by adopting a discrete spectrum interpolation correction formula based on an LSM (Least Square Method), and calculating parameters such as a harmonic frequency, an amplitude, an initial phase angle and the like. Due to the adoption of the method, the fundamental and harmonic components of a tested signal can be detected rapidly and accurately, and accurate frequency measurement is realized; and the method is convenient for implementing an embedded system, and the tested signal can be detected continuously for a long time.

The invention discloses a method for designing a cognitive high-speed wireless communication system under a discrete spectrum condition, and particularly discloses a cognitive high-speed wireless communication system and method under a discrete spectrum condition. The system comprises an authorized frequency band analysis module, an unauthorized frequency band analysis module and a data modulating module, wherein the authorized frequency band analysis module is used for performing frequency spectrum analysis on authorized frequency bands of a communication system to obtain a first available frequency band; the unauthorized frequency band analysis module is used for analyzing other frequency bands of the communication system except the authorized frequency bands or the authorized frequency bands of at least one other system different from the communication system to obtain a second available frequency band; and the data modulating module is used for modulating data to be transmitted in an OFDM/OFDMA (Orthogonal Frequency Division Multiplexing/Orthogonal Frequency Division Multiple Access) mode based on the first available frequency band and the second available frequency band.

A new broadband source having a discrete set of spectral emission lines having high peak power in each line is provided by placing a gain medium in a reflective cavity comprising reflective front and back surfaces. A cavity feedback factor less than unity is achieved by providing reflectivity of one surface substantially lower than the reflectivity of the other surface such that spontaneous emission in the gain medium is linearly amplified just below the lasing threshold. In an alternative arrangement, a movable external back surface placed at a prescribed distance from the gain medium provides a means to achieve a free spectral range and finesse of the emission lines to match a pitch of a detector array in a SD-OCT system. By simultaneously providing high power to each detector element of the array, sensitivity and imaging speed of SD-OCT system are significantly improved.

The invention provides a phase difference measuring method based on improved windowing discrete Fourier transform. The phase difference measuring method includes the first step of collecting two periodic signals to be measured, the second step of analyzing the collected periodic signals to digital signals, the third step of carrying out windowing processing on the digital signals by constructing a 4-step Blackman-Harris window, and carrying out FFT spectral analysis on the signals subjected to windowing processing to obtain signal frequency spectrums, extracting fundamental wave parameters and respectively calculating initial phase angles of the periodic signals to be measured, and the fourth step of correcting phase positions of useful frequency spectrums according to a discrete spectrum correction method so as to calculate the phase differences of the periodic signals to be measured. The phase difference measuring method can effectively solve the problems that a time domain of a DFT algorithm is cut off, the introduced spectrums are revealed, and spectral analysis has bigger errors caused by the picket fence effect, overcomes the defects of spectrum leakage and lower frequency resolution in an interpolation method, improves the frequency resolution, and finally achieves the high-precision measurement of the phase differences.

The invention discloses a method for calculating the dielectric loss angle of a compatible insulating device in the technical field of monitoring. According to the technical scheme, firstly, a Blackman self-convolution window is constructed, current and voltage signals of a device to be detected are collected, and discrete sampling is performed on the current and voltage signals; secondly, windowing truncation is performed on a discrete signal sequence with the constructed Blackman self-convolution window, and a discrete spectrum function of discrete signals after the windowing truncation is obtained; thirdly, the discrete spectrum function of the discrete signals after the windowing truncation is analyzed, and a main lobe width and side lobe characteristics are obtained; finally, voltage and current fundamental wave signal phase angles are solved with the four spectral line interpolation amendment theory, and therefore the dielectric loss angle is solved. According to the method for calculating the dielectric loss angle of the compatible insulating device, the extremely good spectrum leakage restraining effect of the Blackman self-convolution window is used, frequency spectrum correction is performed with the four spectral line interpolation, dielectric loss angle measuring errors based on the FFT theory under asynchronous sampling are avoided, the measuring precision is high, and requirements for hardware are low.

The invention discloses a sparse-decomposition-based hybrid fault feature extraction method of a gear wheel and a bearing, wherein the method can be used for diagnosing a hybrid fault formed by a distributed gear wheel fault and a local gear wheel and bearing fault in a gear case. When a steady modulation dictionary is constructed, atomic parameter optimization is carried out by using a discrete frequency spectrum correction technology, thereby improving precision of steady modulation component separation. When an impact modulation dictionary is constructed, an over-complete dictionary using a multi-stage inherent-frequency unit impulse response function as an atom is established and the inherent frequency and the damping ratio are identified in a self-adapting mode from a fault vibration signal, so that an impact response waveform caused by local faults of the gear wheel and the bearing can be represented well. After optimization of the steady modulation dictionary and the impact modulation dictionary, the dictionary redundancy is substantially reduce; and with a segmented matching tracking method, the point number of inner product calculation during the sparse coefficient solving process is reduced. On the basis of the two kinds of measures, the speed of signal sparse decomposition is improved.

The invention relates to a harmonic energy metering method of Nuttall self-convolution weighted Fourier transform. The method comprises the following steps that: a discrete Nuttall window sequence with a length of N is constructed; convolution operation is carried out on the discrete Nuttall window so as to obtain a convolution sequence; zero filling is carried out on the head or the tail of the convolution sequence so as to obtain a discrete Nuttall self-convolution window; the Nuttall self-convolution window sequence is utilized to carry out weighted operation on a discrete power signal; Fourier transform is employed to obtain a discrete frequency spectrum of the power signal; spectral lines with a greatest amplitude and a second great amplitude are searched nearby a harmonic frequency corresponded to the discrete frequency spectrum; fitting is carried out on a peak value spectral line by utilizing a least square method so as to obtain an amplitude, a frequency and an initial phase angle of a power harmonic wave, so that integral harmonic energy metering in a complex power signal is realized.

The invention discloses a time frequency overlap signal parameter estimation method under Alpha stable distribution noise. The steps include: computing generalized fourth order circulation cumulants of the time frequency overlap signal under Alpha stable distribution noise and setting generalized fourth order circulation cumulant magnitude spectra beta-|GC<beta>(r, 40)| and beta-|GC<beta>(r, 42)| to zero in a small neighbourhood [0, delta0] in which the cycle frequency beta=0; detecting the highest spectrum lines P1 and P1* in beta-|GC<beta>(r, 40)| and beta-|GC<beta>(r, 42)| respectively according to a discrete spectrum line detection method, then setting the amplitude value GCmax of the spectrum line in beta-|GC<beta>(r, 40)| and the amplitude value GCmax* of the spectrum line in beta-|GC<beta>(r, 42)| to zero in small neighbourhoods [P1-delta0, P1+delta0] and [P1*-delta0, P1*+delta0], and thus cycle frequencies corresponding to P1 and P1* being a carrier wave velocity fc1 and a code element velocity fb1 of one of signal components of the time frequency overlap signal; and under the conditions that the code element velocities and the carrier wave frequencies of the overlap signal components are different, detecting the code element velocities of other signal components of the time frequency overlap signal in sequence according to the discrete spectrum line detection method, till the amplitude value GCk+1* of the (k+1)th spectrum line in beta-|GC<beta>(r, 42)| being smaller than GCmax*/2, judging the number of mixed signals to be k at this time, and detecting the carrier wave frequencies of other signal components of the time frequency overlap signal in sequence according to the discrete spectrum line detection method.

Described herein are spectrometers comprising one or more wavelength-selective filters, such as guided mode resonance filters. Some of the spectrometers described herein are configured for obtaining absorbance spectra in a discrete fashion by measuring absorbances of a sample at multiple discrete wavelengths or wavelength bands. In another aspect, methods are also provided for obtaining spectra, images and chemical maps of samples in a discrete fashion.

The invention discloses a sparse reconstruction-based broadband radar high-speed group-target resolving method, which comprises the following steps: 1, keystone transformation is carried out on broadband radar echo signals of a space high-speed group-target, keystone transformation is realized through chirp-z transformation, and a discrete spectrum SCZT (m, n) of the mth broadband radar echo signal of the space high-speed group-target in a Doppler ambiguity-existing range frequency domain is obtained; 2, a relationship between an observation data matrix XCZT and a range Doppler two-dimensional complex amplitude matrix GMN of the space high-speed group-target is deduced; 3, a relationship between the observation data matrix XCZT and a range Doppler two-dimensional complex amplitude matrix G'(M*L)N of the high-speed group-target between space and time with different Doppler ambiguity times is deduced; 4, a problem of detecting and resolving the high-speed group-target between space and time with different Doppler ambiguity times is converted into a sparse optimization problem, and the range Doppler two-dimensional complex amplitude matrix G'(M*L)N of the high-speed group-target between space and time with different Doppler ambiguity times is obtained; and a range Doppler plane of the space high-speed group-target is drawn, and coherent accumulation and resolution of the space high-speed group target can be realized.

The invention provides a harmonic measurement method which aims at obtaining a high-accuracy harmonic measurement result. The method comprises the following steps: sampling a signal to be measured; carrying out DET or FFT treatment on the sampling result to obtain a discrete spectrum; and selecting a plurality of measurement errors caused by spectral line revising long-range spectrum leakage, short-range spectrum leakage, negative frequency point leakage and the like from the discrete spectrum to obtain the high-accuracy harmonic measurement result. The method of the invention can be applied to the field of accurate harmonic measurement.

The invention discloses a harmonic measurement channel calibration method based on an MIR-RSD high-precision cosine window interpolation FFT algorithm, which comprises a data acquisition module, a harmonic parameter detection module used for carrying out windowing interpolation FFT algorithm on data and a calibration module used for harmonic measurement channel parameter adjustment, wherein the harmonic parameter detection module adopts the MIR-RSD high-precision cosine window based interpolation FFT algorithm, time-domain signals are subjected to MIR-RSD windowing and discrete Fourier transform so as to acquire a discrete spectrum Xw(k), a spectrum line k1 with the amplitude being the maximum near the frequency fN in the discrete spectrum, a spectrum line k2 at the left of the spectrum line k1 and a spectrum line k3 at the right of the spectrum line k1, the corresponding frequency spectrum amplitudes are abs(X(k1)), abs(X(k2)) and abs(X(k3)) respectively, a weighting ratio coefficient beta is calculated, then a non-integer portion frequency component delta is solved, the amplitude, the frequency and the phase angle are obtained according to a value of the delta to act as standard values, and the calibration is carried out on the harmonic measurement channel to be calibrated.

A channel estimator for use in a receiver node receiving signals from a plurality of user terminals wherein each user terminal is allotted a respective set of transmission subcarriers and respective test signal sequences for transmission over the channel to be estimated. The channel estimator has stored therein information as to the respective sets of transmission subcarriers allotted to the user terminals for transmission as well as the discrete spectra of the respective test signal sequences allotted to the user terminals. Upon receiving from a plurality of user terminals signals including the respective test signal sequences transmitted over the channel by using the respective sets of transmission subcarriers allotted thereto, the estimator generates the discrete spectrum of the combined test signal received and performs channel estimation as a function of the discrete spectrum of the combined test signal and the discrete spectra of the test signal sequences allotted to the user terminals. A frequency domain channel estimation is performed for a single carrier frequency division multiple access system.

The invention provides a distance measurement method for a frequency modulation continuous wave radar system. The method comprises the following steps: Step S1. discrete intermediate frequency signals collected by the frequency modulation continuous wave radar system are subjected to discrete Fourier transformation to find out the spectral line number km of the discrete spectrum maximum and the spectral line number kc of the discrete spectrum second-maximum; Step S2. the procedure goes to Step S4 if the number kc=km-1, and goes to Step S3 if kc is not equal to km-1; Step S3. the frequency domain in the discrete intermediate frequency signals is shifted to the right based on delta f/2 to make the spectral line numbers km and kc after shifting meet kc=km-1, wherein delta f is the frequency resolution of the discrete Fourier transformation of the N point; Step S4. the discrete intermediate frequency signals are subjected to discrete Fourier transformation by reducing one sampling point to find out the spectral line number k'm of the discrete spectrum maximum; Step S5. the spectral line number k'm of the discrete spectrum maximum is judged, Step S4 is repeated if k'm=km, and the procedure goes to Step S6 if k'm is not equal to km and k'm=km-1; and Step 6. the distance interval (R1, R2) between the radar and the target is worked out according to the sampling point number of the discrete Fourier transformation and distance relational expression, and the distance value between the radar and the target is R'=(R1+R2)/2.

The invention discloses a service communication method of a broadband terminal in a discrete spectrum communication system, comprising the following steps: when the broadband terminal needs to perform service data transmission, the base station distributes broadband frequency ranges to the broadband terminal and transmits identification information of the distributed broadband frequency ranges to the broadband terminal through a downlink control information command; the broadband terminal migrates from own resident frequency range to the broadband frequency range identified by the broadband frequency range identification information and transmits service data and related control signaling in the broadband frequency range. The service communication method enables the discrete spectrum communication system to simultaneously support narrow-band terminals and broadband terminals and meet own service demands.

A low-complexity large-scale MIMO channel parameter estimation method comprises the following steps: step 1, constructing a MIMO system channel model; step 2, after a base station receives data, performing discrete Fourier transform on the received data by using an FFT algorithm; step 3, reconstructing a continuous spatial domain spectrum of received signals for an obtained spatial discrete spectrum of the receive signals through interpolation; and step 4, analyzing the continuous spatial domain spectrum obtained in the step 3 and estimating an angle of arrival and amplitude attenuation of thereceived signals on different physical paths. According to the method provided by the invention, the spatial discrete spectrum of the signals is obtained through the FFT algorithm and then the continuous spatial domain spectrum of the signals is obtained by means of zero-padding and interpolation techniques, so that the spatial continuous spectrum of the received signals can be recovered more accurately. Finally, incident angle parameters and amplitude of the signals when the signals arrive at the base station through physical channels can be estimated according to a peak value of the continuous spatial spectrum. The algorithm is low in complexity and pilot pollution does not exist.

The invention discloses a method for extracting frequency components in dynamic distorted sinusoidal signals and a device for implementing the method. The method comprises weighting discrete distorted sinusoidal signals through a triangular Haning time domain convolution window, subjecting the weighted signals to discrete Fourier transform to obtain discrete spectra, finding spectral lines with a first, second and third largest amplitude values in the discrete spectra, calculating leakage weights on left and right sides of peak spectral lines of the three found spectral lines, and using an arithmetic mean of the leakage weights to obtain a frequency component deviation value. According to the method for extracting frequency components in dynamic distorted sinusoidal signals and the device for implementing the method, spectrum leakages are cancelled and inhibited, and accordingly, frequency and amplitude values of frequency components in dynamic distorted sinusoidal signals are extracted accurately.

The present invention discloses an ultraviolet quasi-single pure-rotation Raman spectrum extraction-based all-day temperature measurement laser radar. The laser radar comprises a laser emitting unit, an optical receiving unit and a signal acquisition and control unit. The laser emitting unit emits the ultraviolet laser of 354. 82 nm in wavelength and the ultraviolet laser is adopted as a detection light source. The laser emitting unit sends a pulse laser beam to the atmosphere. The pulse laser beam and atmospheric particles interact to generate a series of discrete spectrum line scattering signals. The optical receiving unit receives the scattering signals through a telescope and then respectively and simultaneously extracts elastic scattering signals and quasi-single-branched anti-stoke pure-rotation Raman spectral line signals through three channels. The signal acquisition and control unit realizes the real-time acquisition and the inversion of signals, so that the normal and orderly operation of the entire laser radar system is ensured. According to the technical scheme of the invention, the signal-to-noise ratio of the system is enhanced, and the light-receiving path is optimized. The system stability is improved. The all-day detection of the atmospheric temperature, the aerosol space distribution and time evolution parameters is implemented.