16 results about "Discrete-time signal" patented technology

The present application relates to a parameter estimation method, a positioning method, and an apparatus. The parameter estimation method includes: discretizing the incident angle in the channel steering vector on a grid to determine the coefficient matrix expression in the continuous-time signal representation model; performing baseband sampling on the received signal to obtain a discrete-time signal representation model of the received signal on M antennas after reflection from the reflector; using the coefficient matrix expression, the discrete-time signal representation model, and the transmit signal matrix to obtain a sparse representation model of the received signal based on the angle domain and the delay domain; based on the sparse representation model, obtaining a joint estimation problem for characterizing channel estimation and signal detection, and solving the joint estimation problem to obtain a channel estimation value and a transmit signal estimation value. The present application can reduce pilot overhead for channel parameter estimation.

A transmitter in a wireless communication network includes a bits-to-symbol mapper that produces a plurality of data symbols; and a waveform modulator that receives a first discrete-time waveform and at least a second discrete-time waveform that comprises a cyclic shift of the first discrete-time waveform; modulates a first one of the plurality of data symbols onto the first discrete-time waveform and modulates a second one of the plurality of second data symbol onto the second discrete-time waveform, to produce a plurality of modulated discrete-time waveforms; and sums the plurality of modulated discrete-time waveforms to produce a modulated discrete-time signal to be transmitted in the network. The first discrete-time waveform and at least the second discrete-time waveform are multicarrier signals.

The invention provides a double-spectrum super-division enhanced non-contact multi-physiological-parameter synchronous detection method, and relates to the field of physiological parameter detection.The method comprises the steps that a visible light image and a thermal infrared image are collected and processed to obtain a visible light image sequence and a thermal infrared image sequence; performing enhancement processing on each frame of image in the visible light image sequence and the thermal infrared image sequence to obtain a visible light target sequence and a thermal infrared image target sequence; an rPPG signal and a respiration signal are obtained through extraction; and performing signal processing to generate a first discrete time signal sequence and a second discrete time signal sequence which are aligned. According to the invention, non-contact synchronous detection can be carried out on multiple physiological parameters such as heart rate and respiratory rate under strong interference conditions of illumination and movement, and two groups of signal sequences which have a constant sampling rate and are accurately aligned in the time dimension are generated through image enhancement, signal extraction and signal data alignment processing; therefore, the physiological state of the individual is accurately evaluated based on multiple physiological parameters.

The application provides a kind of dual-spectrum super-resolution enhanced non-contact multi-physiological parameter synchronous detection method, it is related to physiological parameter detection field, the method comprises: visible light image and thermal infrared image are collected and image processing is carried out to obtain visible light image sequence and thermal infrared image sequence;Each frame of image in visible light image sequence and thermal infrared image sequence is carried out enhancement processing, and visible light target sequence and thermal infrared image target sequence are obtained;rPPG signal and respiration signal are extracted;Signal processing is carried out to generate aligned first discrete time signal sequence and second discrete time signal sequence.The application can carry out non-contact synchronous detection to heart rate, respiratory rate and other multi-physiological parameters under strong interference conditions of illumination and motion, by image enhancement, signal extraction and signal data alignment processing, generate two groups of signal sequences with constant sampling rate and accurate alignment in time dimension, so as to accurately evaluate the physiological state of individual based on multi-physiological parameter.

The embodiment of the invention discloses a signal sampling method under arbitrary sampling rate conversion with designable frequency response. According to one specific embodiment, the method comprises the steps that a first discrete time signal is obtained, the first discrete time signal is collected by front-end equipment, and the front-end equipment correspondingly has a fixed signal sampling rate or a limited signal sampling rate; the first discrete time signal is filtered through a least square filter, a second discrete time signal is obtained, and a signal sampling interval corresponding to the first discrete time signal is different from a signal sampling interval corresponding to the second discrete time signal; the least square filter is a template filter which is constructed based on passband gain, stopband attenuation, passband cut-off rate and stopband starting frequency and is used for carrying out signal sampling at any sampling rate. According to the embodiment, the conversion of any sampling rate is realized, and the multi-sampling-rate signal processing requirement of the signal acquisition system is met.

The invention discloses a nuclear pulse rectangle forming method of a digital nuclear energy spectrum measurement system. Aiming at a digital nuclear energy spectrum measurement system using a scintillator detector, the method does not adopt nuclear pulse amplitude to represent incident particle energy, but solves the incident particle energy according to an area formula of discrete time signals, then takes an energy value as rectangular amplitude in a time domain, and can form a rectangular pulse with adjustable bottom width through simple operation. And the original nuclear pulse data are converted into rectangular waves formed by rectangles. Compared with a classical nuclear pulse forming method, the rectangle forming method does not need complex operation such as a z transformation method, a convolution method or a recursion method, is small in design difficulty, small in calculation amount, low in cost and easy to implement in a digital chip, and can exert the performance of the scintillator detector to the maximum extent.

The invention provides a non-contact type physiological and psychological artificial intelligence detection method, device and system, and relates to the field of physiological and psychological detection.The system comprises a double-spectrum fusion analysis module, a double-indication capture analysis module and a double-cycle reasoning analysis module; the double-spectrum fusion analysis module is used for generating two discrete time signal sequences which have a constant sampling rate and are aligned in a time dimension so as to represent sign pulsation information; the double-indication capturing and analyzing module is used for identifying state fluctuation information; and the double-cycle inference analysis module is used for carrying out hidden psychological micromotion screening under double cycles. The system can be applied to large-scale health scenes, physical sign pulsation information, state fluctuation information and psychological micro-motion information are comprehensively considered through the double-spectrum, double-indication and double-cycle discriminant analysis technology, accurate physiological and psychological parameter analysis can be carried out, the problems that strong-interference physiological detection is difficult, cross-scene state discrimination is difficult, and the detection accuracy is high are solved. And the development bottleneck of hidden psychological early screening difficulty is overcome.

The application provides a power line carrier channel adaptive equalization method and system for underground coal mines, relates to the field of power line carrier communication, and solves the technical problems of slow convergence speed, large steady-state error and insufficient tracking ability of the adaptive equalization method in the prior art under the time-varying channel and strong pulse interference environment of underground coal mines. The method comprises the following steps: receiving a carrier signal and converting it into a discrete time signal sequence, carrying out wavelet packet decomposition to obtain a subband signal, and calculating a kurtosis value; discriminating the channel state according to the variance of the kurtosis value, and calculating an equalizer step factor by using a state-driven nonlinear compound variable step control law; inputting the signal into a structured decision feedback equalizer embedded in a physical transmission characteristic model constraint; and outputting an equalized signal based on the step factor and the model constraint to adjust the tap coefficient. The application significantly improves the reliability of power line carrier communication in underground coal mines.

A circuit and a method are provided for extracting a digitized DC voltage value representing a magnitude of a discrete-time signal received from a discrete-time system. A first full-wave rectifier performs a full-wave rectification of the discrete-time signal to obtain a full-wave rectified signal, and an oversampling analog-to-digital converter digitizes the full-wave rectified signal to obtain a bitstream. The oversampling ADC includes a second-order or higher order delta-sigma modulator and a filter. The filter is configured to filter the bitstream to extract the digitized DC voltage value.

The invention discloses an electric power communication signal multi-stage anti-saturation amplification method, system and device based on pseudo feature recognition and a medium, and belongs to the technical field of electric power communication signal multi-stage anti-saturation amplification. The signal sequence is sequentially input into a low-noise amplification module and an impedance matching filter for preprocessing; in a sliding time window with a set length, calculating a gradient sequence of signal points in the current window based on the preprocessed signal sequence, and obtaining a variance value of the gradient sequence; comparing the variance value with a dynamically updated global gradient variance reference value, and outputting a filtering signal; and the filtering signal is input to a gain structure composed of three stages of gain amplifiers for gain amplification. According to the method, the problems of false feature misjudgment and signal saturation distortion are solved, multi-path reflection, equipment noise and other false feature interferences can be accurately identified and suppressed through the gradient variance filter, the signal misjudgment rate is reduced, and the operation and maintenance cost of the power terminal in the remote area is reduced.

The present invention provides an adaptive sensing one-dimensional discrete time signal activity detection method and system. First, the spectrum attenuation of the one-dimensional discrete time signal is compensated by pre-emphasis. Then, the pre-emphasized one-dimensional time signal stream is divided into multiple short time frames of fixed length. Then, the frame signal is windowed. Subsequently, the short-time energy integral of the single frame signal is calculated, and dynamic energy threshold adjustment is performed. The threshold adjustment includes adaptive following threshold adjustment and post-stage recognition neural network auxiliary adjustment. After adjustment, a current energy threshold is obtained. A constant is added to the current energy threshold as a decision threshold. Finally, the decision threshold is used to perform signal activity detection and obtain real-time classification results of the signal frame. Through dynamic energy threshold adjustment, the final energy threshold is made to follow the signal amplitude, achieving the purpose of adaptive environment, greatly improving the accuracy of signal activity detection, and reducing device power consumption.

A method for processing data associated with a discrete-time signal, wherein the signal has K many data points, K > 1, each with D many dimensions, D >= 1, wherein the method comprises: forming an autocovariance matrix with respect to the signal for several time positions of a time window of window size Nwin <= K over several dimensions, determining Nen > 1 largest eigenvalues ​​and associated Nen many eigenvectors of the autocovariance matrix, scaling the Nen many eigenvectors based on the respective eigenvalue, whereby Nen many scaled eigenvectors are obtained, organizing the Nen many scaled eigenvectors into a three-dimensional array with Nen many elements in a first dimension, with D many elements in a second dimension, with Nwin many elements in a third dimension, performing at least one convolution operation on the D many dimensions and the Nen many scaled eigenvectors of the array.whereby at least one convolution result is obtained, determining a part of the signal based on the at least one convolution result.

The invention discloses a nuclear pulse right triangle forming method of a digital nuclear spectrum measurement system. Aiming at a digital nuclear energy spectrum measurement system using a scintillator detector, the method does not adopt nuclear pulse amplitude to represent incident particle energy, but solves the incident particle energy according to an energy formula of discrete time signals, and then the energy value is used as right triangle amplitude in a time domain. A right triangle pulse with an adjustable bottom width and an adjustable slope can be formed through simple operation, and original nuclear pulse data are converted into sawtooth waves formed by right triangles. Compared with a classical nuclear pulse forming method, the right triangle forming method does not need complex operation such as a z transformation method, a convolution method or a recursion method, is small in design difficulty, small in calculation amount, low in cost and easy to implement in a digital chip, and can exert the performance of the scintillator detector to the maximum extent.

A circuit interruption device includes a line terminal, a current sensor that measures a current flowing through the line terminal, a zero-crossing detection circuit that measures a voltage and a frequency of the line terminal, and a microcontroller. The microcontroller is configured to apply a digital filter to the line current measurement signal, determine a zero-crossing position of the line voltage measurement signal, count a plurality of turning points of the filtered line current measurement signal, determine a position of each of the plurality of turning points relative to the corresponding zero-crossing position, and determine a position of each of the plurality of turning points relative to the corresponding zero-crossing position. A time between each turning point and a subsequent turning point is determined, and based on the plurality of turning points, a position of each turning point relative to the corresponding zero-crossing position, and the time between each turning point and the subsequent turning point, it is determined whether there is an arc fault within the circuit interruption device.

Provided is a multi-access method (500, 600) and a communication apparatus (102) for uplink transmission of different waveforms. The method (500) comprises receiving (502) an allocation of one or more indices for a respective users for uplink transmission of modulated symbols. The method further comprising transforming (504) the modulated symbols using a first matrix (P) for each index among the one or more indices. Furthermore, the method comprises generating (506) discrete-time signals by upsampling by a factor of plurality of indices by stuffing one or more zeroes, and circularly shifting the upsampled symbols. The method further comprises transmitting (508) uplink signals by combining the generated discrete-time signals of each user for the allocated one or more indices.