In order to reduce a circuit scale and power consumption while maintaining filter performance, a digital filter device includes a first transform circuit for executing a first transform process on data in a predetermined frequency range; a filtering circuit for executing a filtering process by setting an operation bit width of data of a preset first frequency component among the data, on which the first transform process was executed by the first transform circuit, to a different bit width from bit widths of other frequency components; and a second transform circuit for executing a second transform process on the data on which the filtering process was executed by the filtering circuit.

An apparatus monitors physical signals, such as vibration, produced by an asset, such as a motor. Sensor signals corresponding to the physical signals are applied to a bandpass Grtzel filter that passes a frequency band around a characteristic frequency of a physical signal. An analyzer produces information corresponding to the physical condition of the asset based on the Grtzel filtered signal. A tracking unit periodically updates parameters of the Grtzel filter so that the bandpass frequencies of the Grtzel filter track the characteristic frequency of the physical signal. Each Grtzel filter may include a comb filter whose output is applied to a plurality of resonators, whose outputs are applied to a windowing unit. The Grtzel filter is preferably a Grtzel filter block that is made up of a plurality of individual Grtzel filters. The tracking unit continuously updates the operating characteristics of the multiple Grtzel filters within the Grtzel filter block such that one Grtzel filter has a bandpass center frequency at the characteristic frequency and other Grtzel filters have center frequencies that are immediately above and immediately below the characteristic frequency. Thus, if the characteristic frequency changes up or down, the shifted Grtzel filters will pass those frequencies, and the signal at the actual characteristic frequency will not be lost.

Embodiments of the present invention provide a signal processing method and apparatus. The method includes: performing M-way filtering on an input signal to obtain M filtered signals, performing extraction on M filtered signals separately to obtain M extracted signals, performing fast Fourier transform (FFT) on the M extracted signals separately to obtain M frequency-domain signals, and finally determining output signals according to the M frequency-domain signals. According to the embodiments of the present invention, signal filtering and extraction are performed and then FFT is performed.

Systems and methods are provided for channelizing. A first stage can provide a WOLA filter bank that can apply a single multiplier resource to perform window weighting for multiple WOLA filter banks. The first stage can remove mixer-based post FFT adjustment and provide equal functionality with a particular modification of tuning mixers at inputs of second stage FIR paths. The first stage can include a variable decimation, using a particular implementation of variable sample block size.

A process for processing a digital signal comprises constructing a fractional order control system that models a desired frequency response by assembling filter components from a filter component library. The filter components are defined by Laplace functions that include a non-integer control order having a variable fractional scaling exponent. Then, the fractional order control system is adjusted by applying an altitude exponent to the fractional order control system, and the altitude exponent changes a magnitude of the frequency response without changing a width of a transition band of the frequency response. An input signal in the digital frequency domain is received and processed based upon the fractional order control system to generate a digital output that is conveyed.

A method and an apparatus for signal processing: implementing step-by-step orthogonal decomposition of an original signal to be inputted; on the basis of the number of layers of orthogonal decomposition and the edge high frequency bandwidth of the original signal after orthogonal decomposition, generating a finite-length unit impulse response FIR filter; using the FIR filter to filter the edge high-frequency signal of the original signal; and, after passing the signal obtained after filtering and the low frequency signal obtained at each stage of orthogonal decomposition through an orthogonal filter bank, implementing signal synthesis processing.

The first aspect of the invention is related to a new method for automatically detecting physical modes within the data resulting from a modal analysis estimation algorithm (e.g. LSCE, PolyMax or other). The automatic detection method of the invention is based on a non-hierarchical clustering method wherein the number of clusters is automatically optimized, further making use of a metric for spuriousness within each cluster. According to the second aspect of the invention, the method for automatically detecting modes is used in a method removing harmonics from a signal.

An example process includes reducing a quality factor of a first tunable bandpass filter, used, for example, in a low-noise amplifier stage of a polar receiver. A first wideband test signal centered at a desired center frequency of a second tunable bandpass filter is received. A frequency response of the second tunable bandpass filter to the first wideband test signal is estimated using a Fast Fourier Transform (FFT) signal processor. At least a resonant frequency or a quality factor of the second tunable bandpass filter are calibrated based at least in part on a portion of the estimated frequency response of the second tunable bandpass filter obtained from the FFT signal processor. Frequency response characteristics of the first tunable bandpass filter may be similarly tuned in accordance with the example process.

A signal processing arrangement generates electrical stimulation signals to electrode contacts in an implanted cochlear implant array. An input sound signal is processed to generate band pass signals that each represent an associated band of audio frequencies. A spectrogram representative of frequency spectrum present in the input sound signal is generated. A characteristic envelope signal is produced for each band pass signal based on its amplitude. An active contour model is applied to estimate dominant frequencies present in the spectrogram, and the estimate is used to generate stimulation timing signals for the input sound signal. The electrode stimulation signals are produced for each electrode contact based on the envelope signals and the stimulation timing signals.

A method of filtering includes generating a random value by a random number generator circuit, filtering a first signal by a first filter to form a filtered first signal, dithering the filtered first signal using the random value to form a dithered first signal, filtering a second signal by a second filter to form a filtered second signal, and dithering the filtered second signal using the random value to form a dithered second signal.