A memristor crossbar array (MCA) circuit includes an input processor configured to receive an input signal corresponding to a predetermined number of input values and to apply the input signal to memristors arranged along input lines, an MCA including the memristors having resistance values based on at least one transformation matrix including binary element values, and an outputter configured to output a frequency component intensity of the input signal based on a signal that is output from each of output lines on which the memristors are arranged, in response to the input signal being applied to the memristors.

Systems and methods for digital signal processing using a sliding windowed infinite Fourier transform (“SWIFT”) algorithm are described. A discrete-time Fourier transform (“DTFT”) of an input signal is computed over an infinite-length temporal window that is slid from one sample in the input signal to the next. The DTFT with the temporal window at a given sample point is effectively calculated by phase shifting and decaying the DTFT calculated when the temporal window was positioned at the previous sample point and adding the current sample to the result.

A hashing method comprises the steps of converting an input message into a binary input matrix with columns and rows; applying a Fourier Transform (FT) to obtain a multiplication; wherein said FT is an optical FT; and applying a summation across the rows.

It is disclosed a method, an apparatus, a computing device, and a computer-readable storage medium for identifying a signal. The method includes demodulating a modulated signal to generate a transmission signal, transmitting the transmission signal, receiving an echo signal generated by a reflection of the transmission signal, demodulating the echo signal to obtain demodulated information, identifying the demodulated information by using a target network model to obtain an identification result of the echo signal, and outputting the identification result to a graphical user interface for display.

The optimization of circuit parameters of variational quantum algorithms is a challenge for the practical deployment of near-term quantum computing algorithms. Embodiments relate to a hybrid quantum-classical optimization methods. In a first stage, analytical tomography fittings are performed for a local cluster of circuit parameters via sampling of the observable objective function at quadrature points in the circuit parameters. Optimization may be used to determine the optimal circuit parameters within the cluster, with the other circuit parameters frozen. In a second stage, different clusters of circuit parameters are then optimized in “Jacobi sweeps,” leading to a monotonically convergent fixed-point procedure. In a third stage, the iterative history of the fixed-point Jacobi procedure may be used to accelerate the convergence by applying Anderson acceleration/Pulay's direct inversion of the iterative subspace (DIIS).

A method for computing a spatial Fourier transform for an event-based system includes receiving an asynchronous event output stream including one or more events from a sensor. The method further includes computing a discrete Fourier transform (DFT) matrix based on dimensions of the sensor. The method also includes computing an output based on the DFT matrix and applying the output to an event processor.

A device for converting frequency-domain data to time-domain data may be provided. The device may include one or more processors. The one or more processors may be configured to transform frequency-domain data to a complex conjugate symmetric of the frequency-domain data over an entire range of frequencies while maintaining a maximum frequency. The one or more processors may further be configured to apply an Inverse Discrete Fourier Transform operation to the complex conjugate symmetric of the frequency-domain data to generate time-domain data.

Methods, systems and apparatus for simulating quantum systems. In one aspect, a method includes the actions of obtaining a first Hamiltonian describing the quantum system, wherein the Hamiltonian is written in a plane wave basis comprising N plane wave basis vectors; applying a discrete Fourier transform to the first Hamiltonian to generate a second Hamiltonian written in a plane wave dual basis, wherein the second Hamiltonian comprises a number of terms that scales at most quadratically with N; and simulating the quantum system using the second Hamiltonian.

An apparatus for calculating a reception time of a wireless communication signal is disclosed. The apparatus includes a downconverted signal generator configured to generate a downconverted signal, a baseband signal, by downconverting a frequency of a signal received from a transmission source, a modulated signal generator configured to generate a modulated signal by multiplying the downconverted signal by a randomly generated reference signal, a time difference calculator configured to calculate a time difference between the modulated signal and the reference signal by cross-correlating the modulated signal and the reference signal, and a reception time calculator configured to calculate a reception time of the signal received from the transmission source using a point in time at which the reference signal is generated and the time difference between the modulated signal and the reference signal.

A system including an optical receiver to receive a return beam from the target. The optical receiver is to combine a second frequency modulate signal portion transmitted towards a local oscillator with a first frequency modulate portion to produce a beat frequency. The system further including a processor and a memory to store instructions executable by the processor. The processor to sample the beat frequency to produce a plurality of frequency subbands, and classify the plurality of frequency subbands into a plurality of subband types based on a subband criteria. The processor further to select one or more subband processing parameters based on the subband criteria, and process the plurality of frequency subbands, using the subband processing parameters, to determine a range and velocity of the target.