An information processing method for system identification includes: generating a fitting curve represented by a sum of exponential functions for each of a set of digital inputs and a set of digital outputs for a physical system that is represented by one or plural equations including m-order differential operators (m is an integer equal to or greater than 1); and calculating coefficients of the differential operators, which are included in first coefficients, so that a first coefficient of each exponential function included in an expression obtained by a product of the differential operators and the fitting curve for the set of the digital inputs is equal to a second coefficient of the same exponential function, which is included in the fitting curve for the set of the digital outputs.

A system may include a controller that may control operations of a device according to a control loop and characterize a frequency response of the device while the device is operating. The controller may characterize the frequency response by adding a perturbation signal to any signal in the control loop. The controller may then determine a first transformed signal by performing a first discrete Fourier transform on a first signal in the control loop at a frequency of the perturbation signal and determine a second transformed signal by performing a second discrete Fourier transform on a second signal in the control loop at the frequency of the perturbation signal. The controller may then determine the frequency response at the frequency by comparing a first amplitude and a first phase of the first transformed signal to a second amplitude and a second phase of the second transformed signal.

The present document relates to a method for sending and receiving a reference signal and a communication node. The method includes: a first communication node sending a first reference signal and a second reference signal to a second communication node, the first reference signal is different from the second reference signal. The solution achieves the effect that the second communication node acquires channel state quality through the second reference signal which is different from the first reference signal when the second communication node cannot successfully receive the first reference signal.

Provided is a recursive method and apparatus for processing a signal for determining a plurality of frequency components of the signal, the signal being a chirp-like polyphase sequence. In one embodiment, the method includes: (1) determining a first frequency component of the plurality of frequency components, (2) determining a component factor by accessing a factor table, (3) determining the second frequency component using the determined first frequency component and the determined component factor. If there is at least one further frequency component of the signal, the method further comprising for each of the further frequency components: (4) determining a respective further component factor by accessing the factor table, and (5) determining the further frequency component using a previously determined frequency component and the determined further component factor, wherein the previously determined frequency component is the frequency component determined most recently prior to determining each respective further frequency component.

A method of classifying motion from video frames involves generating motion frames indicative of changes in pixel values between pairs of frames. The method also involves determining one-dimensional feature values based on the video frames or motion frames, such as the statistical values or linear transformation coefficients. Each one-dimensional feature value may be stored in a buffer, from which additional temporal feature values can be extracted indicative of the change of the one-dimensional feature values across a set of frames. A classifier may receive the one-dimensional feature values and the additional temporal feature values as inputs, and determine the class of motion present in the video frames. Some classes of motion, such as irrelevant motion, may be considered irrelevant to the execution of certain motion-triggered actions, such that the method may involve suppressing the performance of a motion-triggered action based on the determined class of motion.

A method is described for checking a Generalized Discrete Fourier Transform (GDFT) operation on a secured domain, the method comprising (i) calculating a first checksum based on an input, (ii) determining a result of an GDFT-based operation based on the input, (iii) calculating a second checksum based on the result, (iv) comparing the first checksum and the second checksum and (v) proceeding if the first checksum correspond to the second checksum and otherwise triggering a predefined action if the first checksum does not correspond to the second checksum. Also, an according security device is provided.

An apparatus obtains data comprising magnetic flux density data and an association of the magnetic flux density data to grid points of at least one grid, each grid point representing at least a geographical location. The apparatus applies at least one frequency transform to a representation of the magnetic flux density data and their association to grid points to obtain frequency components. The apparatus provides compressed magnetic flux density data comprising a subset of the obtained frequency components for at least one of storage and transmission. The same apparatus or another apparatus applies at least one inverse frequency transform to the frequency components in order to recover the magnetic flux density data and their association with different grid points and provides the recovered magnetic flux density data and their association with different grid points for supporting a positioning of a mobile device.

Generation of standardized noise signals that provide mathematically correct noise with no errors and no loss of data, and can generate the noise of specific environments based on the transfer function of that environment are discussed. Various embodiments can generate synthetic data sets based on natural data sets that have similar scaling behavior. Fractional scaling digital filters, containing the fractional scaling characteristics of one or more of the eleven fundamental forms of basic building block transfer functions which incorporate the scaling exponent, can be encoded on FPGA devices or DSP chips for use in digital signal processing. Fractional Scaling Digital Filters allow fractional calculus, and thus fractional filtering (e.g., fractional scaling, fractional phase shifting, fractional integration, or fractional differentiation), to be performed on any signal, represent exact filtering solutions rather than approximations, and demonstrably are extremely accurate, highly efficient, and exhibit a higher level of performance than traditional DSP filters.

The disclosure discloses a multiple sinusoid signal sub-Nyquist sampling method based on a multi-channel time delay sampling system. The method includes step 1: initializing; step 2: enabling multiple sinusoid signals x(t) to respectively enter N′ parallel sampling channels after the multiple sinusoid signals are divided, wherein a sampling time delay of adjacent channels is τ, and the number of sampling points of each channel is N; step 3: combining sampled data of each sampling channel to construct an autocorrelation matrix R.sub.xx, and estimating sampling signal parameters c.sub.m of each channel and a set of frequency parameters {circumflex over (f)}.sub.m by utilizing the ESPRIT method; step 4: estimating signal amplitudes α.sub.m and another set of frequency parameters f.sub.m.sup.′ through the estimated parameters c.sub.m and the sampling time delay τ of each channel by utilizing the ESPRIT method; and step S: reconstructing 2K frequency parameters {circumflex over (f)}.sub.m through the two sets of estimated minimum frequency parameters f.sub.m and f.sub.m.sup.′ by utilizing a closed-form robust Chinese remainder theorem, and screening out K correct frequency parameters {{circumflex over (f)}.sub.k}.sub.k=0.sup.K-1 through sampling rate parameters. The disclosure is configured to solve problems of frequency aliasing and image frequency aliasing occurring in real-valued multiple sinusoid signal sub-Nyquist sampling.

Low complexity partial parallel architectures for performing a Fourier transform and an inverse Fourier transform over subfields of a finite field are described. For example, circuits to perform the Fourier transforms and the inverse Fourier transform as described herein may have architectures that have simplified multipliers and/or computational units as compared to traditional Fourier transform circuits and traditional inverse Fourier transform circuits that have partial parallel designs. In a particular embodiment, a method includes, in a data storage device including a controller and a non-volatile memory, the controller includes an inverse Fourier transform circuit having a first number of inputs coupled to multipliers, receiving elements of an input vector and providing the elements to the multipliers. The multipliers are configured to perform calculations associated with an inverse Fourier transform operation. The first number is less than a number of inverse Fourier transform results corresponding to the inverse Fourier transform operation.