911 results about "Self correlation" patented technology

A system and method for determining angular offset of an impulse radio transmitter using an impulse radio receiver coupled to two antennae. The antennae are separated by some known distance, and, in one embodiment, one antennae is coupled to the radio with cable delay. Impulse signals from the antennae are measured to determine the time difference of arrival of one such signal received by one antenna compared to that of the other antenna. Time differential is measured by autocorrelation of the entire impulse radio scan period, by detecting the leading edges of both incoming signals or various combinations of these methods. Using a tracking receiver, the pulses may be continuously tracked thus providing real time position information.

The present invention relates to a method for generating and apparatus for employing code families having desirable correlation properties. Regardless of code length, maximum autocorrelation of the codes is 4 for any nonzero offset and maximum cross-correlation of any two codes from a code family is 4 for any offset. The codes can be used in impulse radio systems and non-impulse radio systems including CDMA, TDMA, FDMA, OFDM and various other frequency hopping and direct sequence systems. The codes can be used to specify various impulse radio and non-impulse radio signal characteristics including pulse position in time, amplitude, width, type, phase, phase difference, frequency, spreading code, etc. The codes have the unique property that they can specify as many as two components in which a signal is not present. A method of code compression is provided.

A method for calibrating an impulse radio distance measuring system comprising an impulse radio transceiver by conducting a pulse through a transmit receive switch to an antenna, receiving return energy which has been discharged across the transmit receive switch, determining a time of arrival of the return energy. The return energy is comprised of two distinct pulses, one of which represents discharge of the transmit switch as the original pulse travels to the antenna, the second represents energy reflected from the antenna and again discharged across the transmit receive switch while the switch is in the transmit position. The timing of the un-reflected energy is determined then the timing of the reflected energy relative to the un-reflected energy is determined through auto-correlation of the time domain scan of the received composite waveforms.

A method and apparatus for microlithography. The method and apparatus include optimizing illumination modes based on characteristics of a specific mask pattern. The illumination is optimized by determining an appropriate illumination mode based on diffraction orders of the reticle, and the autocorrelation of the projection optic. By elimination of parts of the illumination pattern which have no influence on modulation, excess DC light can be reduced, thereby improving depth of focus. Optimization of mask patterns includes addition of sub-resolution features to reduce pitches and discretize the probability density function of the space width.

Light is coupled into two polarization modes of a waveguide, e.g., an optical fiber. The spectral response of Rayleigh backscatter in the waveguide segment for the two polarization modes is measured, e.g., using OFDR, OTDR, OLCR, etc. The autocorrelation of the spectral response is calculated. The spectral (wavelength) shift from a main autocorrelation peak to a side autocorrelation peak, corresponding to one of the two polarization modes of the waveguide segment, is determined. The spectral shift, corresponding to a beat length of the waveguide segment, is multiplied by an average index of refraction to determine a birefringence of the waveguide segment.

A method is provided for a virtual sensor system. The method may include obtaining data records associated with a plurality of input parameters and at least one output parameter and adjusting values of the input parameters based on autocorrelation of respective input parameters. The method may also include reconfiguring the input parameters based on cross-correlation of respective input parameters relative to the output parameter and establishing a first virtual sensor process model indicative of interrelationships between the adjusted and reconfigured input parameters and the output parameter.

An embodiment of the present invention provides an automatic gain control system for a wireless receiver that quickly differentiates desired in-band signals from high power out-of-band signals that overlap into the target band. The system measures power before and after passing a received signal through a pair of finite impulse response filters that largely restrict the signal's power to that which is in-band. By comparing the in-band energy of the received signal after filtering to the total signal energy prior to filtering, it is possible to determine whether a new in-band signal has arrived. The presence of this new in-band signal is then verified by a multi-threshold comparison of the normalized self-correlation to verify the presence of a new, desired in-band signal.

A hearing aid comprises at least one microphone (M) for converting input sound into an input signal, a subtraction node for subtracting a feedback cancellation signal from the input signal thereby generating a processor input signal, a hearing aid processor (G) for producing a processor output signal by applying an amplification gain to the processor input signal, a receiver (R) for converting the processor output signal into output sound, an adaptive feedback cancellation filter for adaptively deriving the feedback cancellation signal from the processor output signal by applying filter coefficients, calculation means for calculating the autocorrelation of a reference signal, and an adaptation means for adjusting the filter coefficients with an adaptation rate, wherein the adaptation rate is controlled in dependency of the autocorrelation of the reference signal.

A packet detection apparatus detects a packet from a received signal by using a preamble containing an established, repeating training sequence. A first autocorrelation calculator computes a first autocorrelation of the received signal over a first interval. A first determining unit determines packet discovery by comparing the first autocorrelation to a first autocorrelation threshold value. A second autocorrelation calculator computes a second autocorrelation of the received signal over a second interval equivalent to the interval length for packet discovery announcement. A second determining unit determines packet discovery announcement by comparing the second autocorrelation to a second autocorrelation threshold value lower than the first autocorrelation threshold value.

A method of localizing signals utilizing auto-correlation functions and cross correlation functions includes: collecting data at a plurality of input channels; filtering the data collected from the plurality of input channels in order to identify a primary signal; identifying at least two lags and at least one reference lag in a function of the data; and estimating relative travel times of the data.

A method of characterizing alignment between two images includes receiving a first data set representative of a reference image, receiving a second data set representative of a target image, processing the first and second data sets that includes calculating an autocorrelation of the first data set to obtain a third data set that is substantially absent information representative of a relative shift between the reference image and the target image, and processing the third data set that includes calculating a Radon transform of the autocorrelation of the first data set to obtain a fourth data set that includes information representative of a relative rotational difference between the reference image and the target image.

The frame words of the preferred embodiment are especially suitable for frame synchronization and / or channel estimation. By adding the autocorrelation and cross-correlation functions of frame words, double maximum values equal in magnitude and opposite polarity at zero and middle shifts are obtained. This property can be used to slot-by-slot, double-check frame synchronization timing, single frame synchronization and / or channel estimation and allows reduction of the synchronization search time. Further, the present invention allows a simpler construction of a correlator circuit for a receiver.

The present invention proposes information processing method and device using time domain pilot sequence in OFDM system. The time domain pilot sequence is filled in the initial part of protecting interval of OFDM sign, and rest part of the protecting interval is filled with the circular prefix of OFDM sign, with FFT block being following the circular prefix. Or, the time domain pilot sequence is filled into the whole protecting interval of each OFDM sign, and FFT block follows the protecting interval. The time domain pilot sequence has self-correlation or periodical self-correlation characteristic, equal amplitude or nearly equal amplitude spectrum characteristic, and length of second power. For sake of system design and according to the features of TP sequence, the present invention proposes some transceiving system, time deviation estimation, carrier deviation estimation and channel estimation method and device based on TP sequence characteristic and OFDM sign structure characteristic.

The invention discloses a self-correlation optical fiber communication system based on mode division multiplexing. The self-correlation optical fiber communication system based on mode division multiplexing comprises an optical carrier input unit, optical signal modulation units, a wavelength division multiplexing unit, a mode division multiplexing and demultiplexing unit, a wavelength division multiplexing unit and coherent reception units. The mode division multiplexing and reconciliation multiplexing unit comprises a mode multiplexer and mode demultiplexer, and the mode multiplexer and the mode demultiplexer are connected through few-mode optical fibers. The optical carrier input unit is connected with each optical signal modulation unit, the wavelength division multiplexing unit and the mode multiplexer through single-mode optical fibers. The mode multiplexer is connected with the mode demultiplexer through few-mode optical fibers. The mode demultiplexer is connected with the wavelength division multiplexing unit and each coherent reception unit through single-mode optical fibers. The optical carrier input unit is further connected with the wavelength division multiplexing unit. The self-correlation optical fiber communication system based on mode division multiplexing eliminates an expensive narrow line width adjustable local oscillator light source which is arranged at a reception end, enables a laser to be conveniently managed and maintained, is free from using frequency offset estimation in a digital signal processor (DSP) and phase retrieval algorithm, reduces complexity of the DSP and has the advantages of being high in spectrum effectiveness and big in nonlinearity tolerance.

A time reference system for generating a time reference from signals produced by a global navigation satellite constellation has a satellite signal receiver to receive and down-convert code-modulated signals from a plurality of satellites and a correlator to track and decode the down-converted signals to provide signals containing partial pseudo-range measurements for respective satellites. A data processing arrangement receives assistance data from an external source and performs data-bit synchronisation in which bit edges of a low frequency data bit stream carried by the received satellite signals are identified, to perform a preliminary position-velocity-time solution to provide an approximate time reference, and to perform auto-correlation of pre-selected data sequences in the data stream to resolve time ambiguities thereby to compute a precise time reference signal in weak received signal conditions. The pre-selected data sequences may be the repeated data preamble in the GPS navigation message constituted by the data stream.

A method for detecting signal and estimating symbol timing is provided. The method is applicable to the receiver in an OFDM system. The method uses the autocorrelation of the short preamble of input signals to detect signals, and performs the coarse frequency offset compensation at the same time. Then, the end of the short preamble for the input signals is detected by the signal detection. The compensated signals are cross-correlated with the portion of the long preamble or that of guard interval together with the long preamble. In addition, the method uses the information for the end of the short preamble to find out a range of the sliding window for estimating symbol timing. In such a manner, the method can make sure of the accuracy for the symbol timing.

A synchronization timing detecting apparatus includes a correlation calculator configured to generate a first correlation value by calculating a cross-correlation between an input signal being sampled and a reference signal or an auto-correlation of the sampled input signal, an interpolation processor configured to generate a second correlation value interpolating a plurality of the first correlation values having a different combination of sampling points of the input signal, and a detector to detect a synchronization timing based on the first and the second correlation values.

A music-synchronized display apparatus includes a beat extractor configured to detect a portion in which a power spectrum in a spectrogram of an input music signal greatly changes and to output a detection output signal that is synchronized in time to the changing portion in synchronization with the input music signal; a tempo value estimation section configured to detect the self-correlation of the detection output signal from the beat extractor and to estimate a tempo value of the input music signal; a variable frequency oscillator in which an oscillation center frequency is determined on the basis of the tempo value from the tempo value estimation section and the phase of the output oscillation signal is controlled on the basis of a phase control signal; a phase comparator; a beat synchronization signal generation and output section; an attribute information storage section; an attribute information obtaining section; and a display information generator.

The invention provides a method and a device for automatically adjusting call volume. The method comprises the following steps: acquiring total voice data through a microphone, and calculating the energy of the total voice data which comprises user voice data and environment noise data; acquiring the energy of the user voice data according to the self correlation of the user voice data; subtracting the energy of the user voice data from the energy of the total voice data to acquire the energy of the environment noise data; and adjusting the call volume according to the energy of the environment noise data. The method and the device of the embodiment of the invention for automatically adjusting the call volume acquire the voice of a user and the environment noise through the microphone of a user terminal, acquire the energy of the environment noise from the total voice acquired by the microphone according to the self correlation of the user voice and the randomness of the environment noise, and then automatically adjust the call volume according to the energy of the environment noise so as to realize accurate automatic adjustment for the call volume.

The invention provides an IQ unbalanced calibration method and equipment of baseband signals in a wireless communication receiving machine. The method comprises the following steps that: the receiving machine receives radio frequency signals, and generates identical phase component path I signals and orthogonal component path Q signals through signal processing; a self correlation valve E(|I|2) of the path I signals, a self correlation value E(|Q|2) of the current path Q signals and a mutual correlation value E(IQ) of the path I signals and the path Q signals are obtained through calculation; carrying out four arithmetic operation on E(|I|2), E(|Q|2) and E(IQ); an estimated value of the current magnitude unbalanced calibration factor and an estimated value of the current phase unbalanced calibration factor are obtained through calculation; and the current path Q signals are calibrated according to the estimated values. The embodiment of the invention can reduce the operation quantity.

A system, method, and signal are disclosed for line probing. The invention provides an improved signal for line probing having desirable characteristics. In various embodiments the signal comprises a periodic sequence having good autocorrelation characteristics. The periodic sequence of the invention provides a faster and more accurate evaluation of the channel. Another embodiment of the invention comprises processing of the received sequence to determine a desired or maximum data rate for the line or channel. The invention also provides an evaluation and calculation of the noise on the line or channel.

The invention provides a Doppler velocity metering laser radar echoed signal processing unit and a method. The processing unit mainly comprises a signal storage module and a DSP module; wherein, the signal storage module is used for storing the echoed signals of a tested object; the echoed signals are digital signals which are converted by A / D; the DSP module is used for reading the echoed signals in the signal storage module and carrying out the FFT to obtain the power spectrum of the signals, and then the rough estimated frequency value is obtained according to the power spectrum; the power spectrum is carried out the inverse FFT and then the self correlation functions of the echoed signals are obtained, the correction frequency value is obtained according to the self correlation functions, the rough estimated frequency value and the correction frequency value are added to obtain the Doppler frequency of the echoed signals, and the movement velocity of the tested object is calculated according to the Doppler frequency. The device and the method combine the self correlation technology with the frequency deviation estimation improvement algorithm which is based on the frequency deviation correction, and the velocity of the test object can be effectively worked out.

Stabilized carrier recovery is achieved even at the time of a low C / N ratio by measuring the phase of a signal and controlling VCO or NCO (Numerical Controlled Oscillator) using only a period having few constellation points. At this time, false lock phenomenon is avoided as follows. That is, relatively short SYNC modulated by an already-known pattern is entered into a modulation wave, VCO or NCO oscillation frequency is swept in a wide range and sweep is stopped at a frequency in which the SYNC can be received, thereby carrying out coarse control AFC. Further, a period having long to some extent, having few constellation points is provided in the modulation wave and then, a difference between the frequency of a received modulated signal and a local oscillation signal of VCO or NCO is obtained in this period. This frequency difference is analyzed according to the phase differential function method, self-correlation function method or count method, and the VCO or NCO is controlled based on this result of analysis.

The invention discloses a mine micro-quake signal P wave first arrival moment joint pickup method and mainly solves the technical problems that a single PAI-K and AIC method is high in pickup precision but is unstable in pickup of low signal to noise ratio, spike, tail shock and pure noise signals. The method comprises the following steps: extracting mine micro-quake signal waveform data; carrying out maximum kurtosis value arrival time (K1) pickup; carrying out minimum self-correlation value arrival time (K2) pickup; and judging whether | k1-k2 | is larger than a threshold value L, if so, abandoning the micro-quake signals, or otherwise, outputting P wave arrival time k=k2. Through PAI-K_AIC joint identification, interference of low signal to noise ratio, spike, tail shock and pure noise signals is effectively eliminated, mistake pickup rate is greatly reduced, and P wave pickup stability is enhanced. The method has the advantages of simple processing, high applicability and high accuracy and the like.

The invention discloses a training sequence frame timing synchronized method based on pseudo-random sequence modulation, which can be applied in an orthogonal frequency division multiplexing system or a single carrier frequency domain equalization system, and comprises the following steps: (1) carrying out an energy detection by using the relevance of the front part and the back part of a training sequence at a receiving terminal; (2) taking the certain range around the peak position of the energy detection as a rough synchronization timing range; (3) in the rough synchronization timing range, using a local frame leading sequence generated by the receiving terminal to carry out the cross-correlation with a receiving sequence, according to the peak position of the cross-correlation, determining the position of the local frame accurate synchronization timing, wherein the first half part of the leading training sequence is gained by modulation of cascade sequence of self-correlation of a plurality of constant amplitude zero values by adopting the pseudo-random modulation sequence, and the second half part thereof is inverse operation of the first half part. The method can gain higher timing accuracy by using the pseudo-random modulation sequence to carry out the complex fine synchronization.

A method of determining when an image capture device with a rolling shutter is in an environment having a flickering illuminant by using autocorrelation or frequency analysis of difference vectors produced from first and second captured images.

The invention relates to a method for predicting city traffic accidents based on time-space distribution characteristics. The method comprises: first, in combination of the case information and the space information, creating a case space database and performing pretreatment to the data; then, based on surface area statistics, analyzing the traffic accidents' time-space distribution characteristics; using the global and local self-correlation method to realize the analyzing of the aggregate state; based on the case happening point data, analyzing the traffic accidents' time-space distribution characteristics; through the hierarchical clustering analysis, expressing the distribution rule of the cases hierarchically; through the nuclear density estimation method, expressing the continuous changes and accurate gathering center of the traffic accidents' happening distribution; and finally, utilizing the BP neural network prediction algorithm, using the time-space distribution characteristics of the already happened cases to predict the time-space distribution areas of traffic accidents in the future. According to the invention, in combination with the time-space distribution and through the utilization of big date excavation BP neural network prediction algorithm and the time-space distribution characteristics of the already happened cases to predict the time-space distribution areas of traffic accidents in the future, it is possible to increase the precision, the timeliness and reduce the manual cost.

The invention provides a target tracking method based on multi-characteristic adaptive fusion and kernelized correlation filtering technology. The method comprises steps of according to target position and the dimension of the previous frame tracking, acquiring a candidate region of target motion; extracting histogram characteristics and color characteristics in the gradient direction of the candidate region, fusing the two kinds of characteristics, carrying out Fourier transform so as to obtain a characteristic spectrum and then calculating kernelized correlation; determining the position and the dimension of the target at the current frame, and acquiring a target region; extracting histogram characteristics and color characteristics in the gradient direction of the target region, fusing the two kinds of characteristics, carrying out Fourier transform so as to obtain a characteristic spectrum and then calculating kernelized self-correlation; designing the adaptive target correlation and training a position filter model and a dimension filter model; and using a linear interpolation method to update the characteristic spectrums and the related filters. According to the invention, the discrimination capability of the models is improved; robustness of the target tracking of the target in a complex scene and the appearance change is improved; calculation complexity is reduced; and tracking timeliness is improved.

The invention provides an integral coding / decoding method based on MIMO radar communication. The orthogonal spread spectrum code sequence guarantees the orthogonality of bipolar phase spread spectrum code sequence based on WalsH matrix. The requirement of the radar to the detection of signal self-correlation peak value, mutual correlation peak value low side-lobe can be satisfied through the genetic algorithm. The signal encoding is based on soft spread spectrum biorthogonal encoding. To satisfy the requirement of the MIMO radar to detection signal, different spreading coding sequences can be used on different encode element positions; special sending channel can be reserved as the time and frequency synchronous standard, the first encode element position of each sending channel is reserved as the phase position standard, and special synchronous spreading codes are used on the positions. According to the method provided by the invention, conventional carrier frequency offset extraction technology, carrier phase partial extraction technology and soft spread spectrum biorthogonal decoding method are improved specifically according to the requirement of the radar / radio frequency integrate realization, accompanied by the frequency offset tracking technology with Alpha -Beta as the core, accuracy of data deviation correction is guaranteed.