123results about How to "Reduced sampling rate requirements" patented technology

Implementations of the present principles include methods, systems and apparatuses for transmitting data through a sub-carrier multiplexing and orthogonal frequency-division multiple access passive optical network. In accordance with aspects of the present principles, a plurality of optical network units are assigned electrical carrier frequency bandwidths that are narrower than a system capacity bandwidth. Modulation of optical waves transmitted between an optical line terminal and each optical network unit is conducted on different orthogonal sub-carrier frequencies within the assigned bandwidths such that sampling of said orthogonal sub-carrier frequencies is limited to the assigned electrical carrier frequency bandwidths. The waves are thereafter received and demodulated for the extraction of data.

The present invention generally relates to echo cancellation over an asymmetric transmission and receiving spectra. An apparatus is provided having a transmit path and a receive path, with an adaptive echo canceler disposed therebetween, for communicating data within a first bandwidth and a second bandwidth respectively. A first decimator is disposed between the transmit path and the echo canceler circuit and filters an incoming signal having a first sampling rate and emits a signal output at a second, reduced sampling rate. A second decimator is disposed along said receive path and filters an incoming signal and emits a signal output at a reduced sampling rate. An adder is disposed to subtract the output of the adaptive echo canceler from output of the second decimator to generate a received signal that is substantially free of echo.

The invention relates to a method for generating random numbers in which oscillating digital output signals (A1, A2, . . . , AL) of unequal or equal periodicity are generated by at least two ring oscillators (32, 33, 34), an external parity signal (PS) representing a logical state (“0,”“1”) being generated when an odd number of the output signals (A1, A2, . . . , AL) take on a specified logical state (“1”). According to the invention, the external parity signal (PS) is fed back to an external parity input (36, 37, 38) of each of the respective ring oscillators (32, 33, 34). The invention further relates to a random number generator having at least two ring oscillators (32, 33, 34), made up in particular of independently free-running inverter chains with feedback having an odd number (K) of series-connected inverters (inv1,2, inv2,1, inv3,1, . . . , invi,j, . . . , invL,KL) that generate oscillating digital output signals (A1, A2, . . . , AL) of unequal or equal periodicity, and having first parity signal generating means (XOR) that generate an external parity signal (PS) representing a logical state (“0,”“1”) when an odd number of the output signals (A1, A2, . . . , AL) take on a specified logical state (“1”). According to the invention, there are feedback means (xor1, xor2, xor3, xor4, . . . , xorL) that feed back the external parity signal (PS) to an external parity input (36, 37, 38) of each of the respective ring oscillators (32, 33, 34). In this invention the cooperation of chaotic dynamics (feedback of the parity signal) and true randomness (jitter due to thermal noise) in digital circuits, a novel theoretical principle for generating random numbers, has been made into an efficient practical solution.

A storage pixel sensor disposed on a semiconductor substrate comprises a MOS capacitor storage element having a diffusion terminal and a gate terminal. A speed node is connected to the diffusion terminal and biased at either a first control potential or a second control potential, the first potential selected to keep the MOS capacitor in a state of inversion, the second potential selected to keep the MOS capacitor in a state of depletion. A photodiode has an anode connected to a reference potential and a cathode. A semiconductor reset switch has a first terminal connected to the cathode and a second terminal connected to a reset reference potential. A semiconductor transfer switch has a first terminal connected to the cathode and a second terminal connected to the gate terminal of the capacitive storage element. A semiconductor amplifier has an input connected to the gate terminal of the capacitive storage element and an output. The semiconductor reset switch and the semiconductor transfer switch each have a control element connected to a control circuit for selectively activating the semiconductor reset switch and the semiconductor transfer switch. A light shield is disposed over a portion of the semiconductor substrate including the second terminal of the semiconductor transfer switch to prevent substantially all photons from entering the portion of the semiconductor substrate. Structures are present for preventing substantially all minority carriers generated in the semiconductor substrate from entering the portion of the semiconductor substrate. A plurality of storage pixel sensors are disposed in an array.

The system and method for estimating impulse response of a wideband communication channel represented as linear combination of L time-shifted pulsed P1(t) with propagation coefficients a1, comprising functionalities or steps for obtaining an ultrawideband signal (y(t) of FIG. 1) received over the channel, filtered (h(1) of FIG. 1) with low pass / bandpass filter and sampled uniformly at a sub-Nyquist rate; a functionality for determining discrete-Fourier-transform coefficients Yj and Sj (FFT of FIG. 1) from the sampled received signal and a transmitted ultra-wide-band pulse, respectively; a functionality for determining dominant singular vectors of a matrix having Yj+l4 / Sj+i4, as its i, j-elements; a functionality for estimating a plurality of powers of signal poles from the dominant singular vectors and determining the times shifts from the estimated powers; and a functionality for determining the propagation coefficients from a system of linear equalizations.

A method and apparatus to inexpensively and efficiently process audio and speech signals. A method for processing a signal having at least one region of interest is provided. The method begins by dividing the signal into a plurality of sub-band signals, wherein a selected sub-band signal includes the region of interest. The selected sub-band is processed by a phase vocoder to produce a vocoder output signal. Next, at least a portion of the subbands are time-aligned with the vocoder output signal. Finally, the aligned sub-band signals and the vocoder output signal are combined to form an output signal.

A digital ultrasound beam former for ultrasound imaging, that can be configured by a control processor to process the signals from ultrasound transducer arrays with variable number of elements at variable sampling frequencies, where the lowest sampling frequency allows for the highest number of array elements. The maximal number of array elements is reduced in the inverse proportion to the sampling frequency. Parallel coupling of transmit / receive circuits for each element allow adaption of the receive Noise Figure and transmit drive capabilities to variations in the electrical impedance of the array elements.

The invention relates to a power distribution network fault circuit selection method based on transient zero-sequence current time-frequency characteristic vectors, and belongs to the technical field of power system relay protection. When a power distribution network runs into a single-phase earth fault via an arc suppression coil grounding system, a transient zero-sequence current component detected by a measuring end is a nonlinear non-stationary signal formed by different frequency components. By taking the fault component as a study object, time-frequency characteristics of a fault transient current of the fault component are analyzed by utilizing the wavelet packet theory, time-frequency distribution regularities among all feeder lines under different fault conditions are described according to similarity of the time-frequency characteristics, and consequently line selection criteria based on transient zero-sequence current time-frequency characteristics can be obtained. The method is simple in principle, only utilizes short-time window zero-sequence current data of 5ms after the fault, can identify faulty feeders under the conditions of small fault angle and high resistance ground fault, has excellent timeliness and robustness, is free from influence of an arc fault or a resistance ground fault, requires a low sampling rate for hardware, and is highly practical.

A method and a system for transient and intermittent earth fault detection and direction determination in a three-phase median voltage electric power distribution system which comprises many lines. The system comprises: sampling means wherein the residual current and residual voltage on said lines are sampled, transient direction detection means based on instantaneous power, random intermittent detection means based on intermittent change of residual current amplitude, means of integrating transient direction and random intermittent detection, and alarm means indicating maintenance personnel to check the status of one line.

A method and apparatus for determining masked thresholds for a perceptual auditory model used, for example, in a perceptual audio coder, which makes use of a filter bank structure comprising a plurality of filter bank stages which are connected in series, wherein each filter bank stage comprises a plurality of low-pass filters connected in series and a corresponding plurality of high-pass filters applied to the outputs of each of the low-pass filters, and wherein downsampling is advantageously applied between each successive pair of filter bank stages. In accordance with one illustrative embodiment, the filter bank comprises low order IIR filters. The cascade structure advantageously supports sampling rate reduction due to the continuously decreasing cutoff frequency in the cascade. The filter bank coefficients may advantageously be optimized for modeling of masked threshold patterns of narrow-band maskers, and the generated thresholds may be advantageously applied in a perceptual audio coder.

A signal receiver, such as an RF-matched filter receiver, includes an optical source (e.g. a mode-locked laser) providing an optical signal, and a first optical modulator to modulate the optical signal with a received RF signal and provide a modulated optical signal. A second optical modulator modulates the modulated optical signal with a reference signal and provides a twice modulated optical signal. The modulators may be Mach-Zehnder Modulators (MZM) and / or Indium Phosphide (InP) modulators. An optical detector receives the twice modulated optical signal and provides a detected signal, and a processing unit receives the detected signal and extracts or measures cross-correlation between the received RF signal and the reference signal.

The invention discloses a transformer substation local discharge positioning method based on electromagnetic antenna array signal processing. The transformer substation local discharge positioning method is finished by a local discharge detection device, and the local discharge detection device comprises an omnidirectional antenna array, a built-in amplifier, a super-high-speed data sampling unit and a data processing unit which are mounted in a transformer substation. The positioning method comprises the steps as follows: constructing a matrix according to a concept of working out a signal wave arrival direction by a rotation invariant technology based on L-shaped antenna array signal processing; obtaining an azimuth angle of a local discharge source arriving at an antenna; and finishing planar location of the local discharge source of the transformer substation. A time delay sequence of a signal does not need to be calculated, so that the requirement on a sampling rate of an acquisition system can be lowered; and a plane coordinate of the local discharge source is obtained by working out a linear cross point in two wave arrival directions, namely working out a linear equation set in two unknowns, so that calculation of a nonlinear equation set is avoided.

A robust multi-criteria minimum timing for the best torque (MBT) timing estimation method and apparatus utilizes different ionization signal waveforms that are generated under different engine operating conditions. The MBT timing criteria is calculated based upon both ionization and analog derivative ionization. Multiple MBT timing criteria are determined and combined to increase the reliability and robustness of MBT timing estimation based upon spark plug ionization signal waveforms. In a preferred embodiment, a combination of the MBT timing estimation criteria comprises a maximum flame acceleration location, a 50% burn location, and a second peak location.

A digital ultrasound beam former for ultrasound imaging, that can be configured by a control processor to process the signals from ultrasound transducer arrays with variable number of elements at variable sampling frequencies, where the lowest sampling frequency allows for the highest number of array elements. The maximal number of array elements is reduced in the inverse proportion to the sampling frequency. The beam former can be operated both in a RF-sampling mode and a quadrature mode. Parallel coupling of transmit / receive circuits for each element allow adaption of the receive Noise Figure and transmit drive capabilities to variations in the electrical impedance of the array elements.

Methods and systems for controlling communication of data in an ultrasound system are provided. One method includes receiving ultrasound data from a plurality of channels of an ultrasound probe in an ultrasound system and digitally demodulating the received ultrasound data such that a data transfer rate of the digitally demodulated ultrasound data is lower than a data transfer rate of the received ultrasound data. The method further includes processing the digitally demodulated ultrasound data, wherein the processing is performed using a processor of the ultrasound system.

A technique that randomizes a sample window over which one or more interleave mismatch corrections are made to a time interleaved analog to digital converter (TIADC).

The system generally includes a crosspoint switch in the local data collection system having multiple inputs and multiple outputs including a first input connected to the first sensor and a second input connected to the second sensor. The multiple outputs include a first output and a second output configured to be switchable between a condition in which the first output is configured to switch between delivery of the first sensor signal and the second sensor signal and a condition in which there is simultaneous delivery of the first sensor signal from the first output and the second sensor signal from the second output. Each of multiple inputs is configured to be individually assigned to any of the multiple outputs. Unassigned outputs are configured to be switched off producing a high-impedance state. The local data collection system includes multiple multiplexing units and multiple data acquisition units receiving multiple data streams from multiple machines in the industrial environment. The local data collection system includes distributed complex programmable hardware device (CPLD) chips each dedicated to a data bus for logic control of the multiple multiplexing units and the multiple data acquisition units that receive the multiple data streams from the multiple machines in the industrial environment.

The inventive process control system makes use of Optimal control (OC) and model predictive control (MPC) techniques for selection of the Expert Systems (ES) targets U. The ES target U is selected in such a way that the performance criterion J is minimized. In other words, a mathematical model of extended system given by the process P and the ES is developed. This mathematical model has hybrid nature in the sense that both continuous dynamics (mostly process) and logical relationships (mostly ES) appear in it. Controlled variables of the mathematical model are the ES targets U and inputs are the measurements y and the performance criterion J. OC and / or MPC techniques are used to compute U. The optimizer of the OC / MPC selects values of the ES targets U only. This activity has lower sampling rates than selection of C, which makes the design of the OC / MPC controlled easier.

The invention discloses an MIMO radar detection method based on double optical frequency combs and difference frequency multiplexing. According to the method, an existing MIMO radar detection technology based on microwave photon orthogonal difference frequency multiplexing is improved, and M paths of modulated optical signals of a transmitting end are generated through the following method: firstly, an optical carrier is divided into an upper path and a lower path; The local oscillator signal is used for carrying out modulation processing on the uplink optical carrier wave to generate a firstoptical frequency comb signal, and the intermediate frequency signal and the intermediate frequency linear frequency modulation signal are used for carrying out modulation processing on the next optical carrier wave to generate a second optical frequency comb signal; After the first optical frequency comb signal and the second optical frequency comb signal are coupled into one path, the first optical frequency comb signal and the second optical frequency comb signal are divided into M paths of modulated optical signals respectively consisting of a single intermediate frequency linear frequencymodulation spectrum line and a single local oscillator signal spectrum line through beam shaping filtering. The invention also discloses an MIMO radar detection device based on the double optical frequency combs and the difference frequency multiplexing. According to the invention, the structure of the transmitter can be greatly simplified, the implementation cost of the system is reduced, and the coherence between signals can be effectively ensured.

The invention relates to a radar and multi-network fusion based pedestrian pose recognition method and system. The method comprises: pre-processing an echo signal of a radar signal to obtain an outputsignal; suppressing a stationary target in the output signal; searching a pedestrian located distance unit in the suppressed output signal; performing time-frequency analysis on the echo signal corresponding to the pedestrian located distance unit, and obtaining a an echo signal time-frequency map; using a plurality of convolutional neural networks to recognize the echo signal time-frequency map,and obtaining a recognition result of each convolutional neural network; and fusing the recognition results of all the convolutional neural networks, and obtaining the fused pose recognition result.The pedestrian pose recognition method provides a pedestrian pose recognition result in real time by analyzing the radar echo, can ensure high pose recognition accuracy through multi-neural network fusion, is free from interference of factors such as illumination conditions, weather, smoke and the like, and is able to work all day and all weathers.

The invention discloses a digital predistortion system and method achieving undersampling feedback. The system comprise a digital predistorter, a digital-to-analog conversion module, a power amplifier, an analog-to-digital conversion module and a predistortion parameter estimation module; the input end of the digital predistorter is connected with a signal source, and the output end of the digital predistorter is connected with the digital-to-analog conversion module and the predistortion estimation module separately; the output end of the digital-to-analog conversion module is connected with the power amplifier, and the output end of the amplifier is connected with a signal output device and the analog-digital conversion module; the output end of the analog-to-digital conversion module is connected with the predistortion parameter estimation module. According to the digital predistortion system and method, signals output by the power amplifier are converted at the sampling rate lower than the bandwidth of the signals output by the power amplifier, aliasing digital signals are generated, the requirement on the analog-digital conversion rate is lowered, and a predistortion parameter vector is extracted according to the aliasing digital signals to be used for predistortion parameter adjusting of the digital predistorter; the analog-digital conversion sampling rate is decreased, the power consumption and cost of the system are reduced, and meanwhile the linearity index of the power amplifier is guaranteed.

The invention relates to a power distribution network fault line selection method using zero-sequence current full quantity Hough transformation and belongs to the technical field of relay protection of an electrical power system. When a single-phase ground fault of a power distribution network occurs, fault zero-sequence current can be obtained according to three-phase current measured at a protective installing position, zero-sequence current data of each feeder of a 1.5ms short time window is extracted, Hough transformation is conducted, an included angle in the direction of overall changes of an overall change trend at a zero-sequence current full quantity initial phase is formed, relation between the zero-sequence current full quantity initial stage change direction of each feeder and the overall change direction is compared, and power distribution network fault line selection is achieved. By means of the method, noise interference resisting performance of the line selection method can be effectively improved, fault feeders under the condition of small fault angles and high-resistance ground faults can be identified, and fault initial transient data loss can not affect the effectiveness of the line selection method. Simultaneously, the method is good in robustness and is not subject to effects of arc faults, non-linear load influence and the like, requirements for hardware sampling speed are greatly reduced, and good practicality is achieved.

In a graphics system regions of a frame are analyzed to determine local regions of the frame in which adaptive desampling may be performed. In one implementation a standard sampling scheme includes at least one sample per pixel and regions that are adaptively desampled have one sample for a block of pixels having a size of at least four pixels. A level of detail map is generating to identify regions in which desampling may be performed. The level of detail map may be based on detecting motion, detecting an edge, and detecting a content frequency.

The invention discloses an eye graph generating method based on a vector network analyzer. The generating method comprises following steps of (1) carrying out test on a to-be-tested piece via a vector network analyzer and obtaining a scattering parameter of a frequency domain, i.e., the S parameter; 2) fitting the S parameter so as to obtain a transfer function by use of a vector matching method in the vector network analyzer; 3) using a time domain type as input of the transfer function and obtaining transient time domain response of the to-be-tested piece; and 4) carrying out superposition processing on the transient time domain response and obtaining a corresponding eye graph. According to the invention, requirements on sampling speed of an analog-digital converter imposed by an eye graph test are effective reduced; fitting precision of the scattering parameter, i.e., the S parameter is improved; and eye graph test speed of the vector network analyzer is increased.

The invention discloses a digital pre-distortion method and device. The method comprises the steps: carrying out the digital pre-distortion processing of baseband signals of a broadband multiband signal at all frequency bands through searching a corresponding multi-dimensional pre-distortion lookup table, and generating digital pre-distortion signals at all frequency bands; respectively carrying out the digital up-conversion of baseband digital pre-distortion signals at all bands, and generating intermediate frequency digital pre-distortion signals at all bands; carrying out the frequency shift path combination of the intermediate frequency digital pre-distortion signals at all bands, and generating a broadband multiband path combination pre-distortion signal; carrying out the multistage frequency selection of the feedback broadband multiband path combination pre-distortion signal, and separating the distortion feedback signals at all bands step by step; and updating the multi-dimensional pre-distortion lookup table corresponding to the frequency band according to the distortion feedback signal and the baseband signal of the frequency band before pre-distortion. Compared with the prior art, the method can reduce the hardware resources, improves the inter-band processing consistency, and reduces the DPD processing rate.

Embodiments of the present invention provide a method for non-contact detection techniques of mechanical vibrations utilizing a radio frequency system incorporating multiple carrier wavelengths. The new detection method measures multiple harmonic pairs at a carrier frequency and improves the detection accuracy and reliability by first inspecting the Bessel function coefficient of each harmonic and then determining the harmonic amplitude. The original mechanical vibration can then be reconstructed. Embodiments can be used to realize sensing of complex non-sinusoidal vibrations using a wavelength division sensing technique and allow non-contact detection through walls, smoke, fog or other low visibility environments with the advantage of longer range detection and easy integration at a low cost.

This invention relates to a device for and method of implementing an ambient noise-cancellation (ANC) circuit that uses digital processing whereby a signal indicative of the ambient noise is converted to digital form, filtered, using a fixed or adaptive digital filter, and then converted back to analogue before sending it to an ear-proximate speaker. In order to address the time delays associated with such processing operations, the analogue-to-digital converter used is associated with a down-sampler, and the arrangement is such that a first part of the filtering is implemented by the down-sampler, and a second part of the filtering is implemented by the digital filter. This reduces group delay by configuring a down-sampler associated with the front end of the analogue-to-digital converter to incorporate selected filter characteristics of the overall ANC filter response, and modifying the subsequent filtering processing stage to compensate for this.

The invention discloses a single-sideband modulation type time-domain broadening analog-to-digital converter, which comprises a supercontinuum laser source (10), a hybrid coupler (20), an electro-optic modulator (30) and a photoelectric converter (40). The supercontinuum laser source (10) is used for producing an ultrashort optical pulse train and outputting the ultrashort optical pulse train to the electro-optic modulator (30) through a first optical fiber (1); the hybrid coupler (20) is used for coupling electric signals to be detected which are received by a first port and outputting two electric signals with identical frequencies and 90-degree phase difference to the electro-optic modulator (30); the electro-optic modulator (30) is used for intensity modulation of the optical pulse train output by the first optical fiber (1) through receiving the two electric signals from the hybrid coupler (20) and receiving a bias voltage with a fourth port, wherein the optical pulse train after modulation is output to the photoelectric converter (40) through a second optical fiber (2); and the photoelectric converter (40) is used for the photoelectric conversion of the optical pulse train output by the second optical fiber (2) and the output of electric signals after conversion to an ordinary analog-to-digital converter (50). The invention can lower requirement for the sampling rate of the electronic analog-to-digital converter.

The invention provides a method for identifying the absolute stress of a steel component based on transverse wave spectrum analysis. According to the method, the absolute stress of the steel component is solved by calibrating the correlation coefficient between the stress of transverse waves on a replica of an in-service steel component and the reciprocal of a first characteristic frequency and by detecting a first characteristic frequency value of an amplitude spectrum curve of the propagation signals of the transverse waves on the in-service steel component. The invention has the beneficial effects that non-destructive testing of the absolute stress of the in-service steel component can be realized; requirements on the sampling rate of a data acquisition system during testing is not high; and the testing is barely affected by the high-frequency noise of an environment.

A method and apparatus for an image canceling digital-to-analog converter is disclosed. Up-sampling and noise shaping is used to produce a stream of digital sample values at a relatively higher sampling rate than the sampling rate of the digitized input samples, each higher sampling rate sample having fewer bits than the original samples. The higher sampling rate stream is then distributed for sequential conversion by multiple digital-to-analog converters each operating at a lower sampling rate. The outputs of the converters are then combined to form a combined output signal. Most spectral images normally observed in a standard or conventional DAC are attenuated in the combined output signal of an embodiment in accordance with the present invention. Any spectral images that remain are further from the signal of interest, permitting the use of lower cost filtering.