A parallel transfer rate converter inputs first parallel data with number of samples being S1 pieces in synchronism with a first clock, and outputs second parallel data with number of samples being S2=S1(m/p) pieces (p is an integer equal to or larger than 1) in synchronism with a second clock having a frequency which is p/m times of a frequency of the first clock. A convolution operation device inputs the second parallel data in synchronism with the second clock, generates third parallel data with number of samples being S3=S2(n/m) pieces (S3 is an integer equal to or larger than 1) by executing a convolution operation with a coefficient indicating a transmission characteristic to the second parallel data, and outputs the third parallel data in synchronism with the second clock.

An apparatus for modifying a sampling rate includes a forward transformer for forming a first version of a spectrogram by means of transformation with a first transformation length from an information signal with a first sampling rate. The apparatus includes a processor for forming a second version of the spectrogram with a lower bandwidth than the first version. The apparatus includes a reverse transformer for forming a coarsely pre-modified information signal with a second sampling rate that is reduced with respect to the first sampling rate, by means of reverse transformation of the second version of the spectrogram with a second transformation length that is reduced with respect to the first transformation length. The apparatus includes a time domain interpolator for acquiring an information signal with a third sampling rate that is modified with respect to the second sampling rate, by means of interpolation of the pre-modified information signal.

A method, apparatus, and computer program product for calculating a sampled signal are disclosed. A method in accordance with the disclosure may include determining discrete samples of a continuous signal having a finite spectrum and using a function series expansion to calculate at least a portion of the continuous signal over the discrete samples. In accordance with some embodiments, an original signal may be calculated over discrete samples with arbitrary accuracy. Polyphase filtering is not used in some embodiments. Some embodiments can be used for arbitrary, including irrational, variation of the sampling rate of the signal with a bounded spectrum. Some embodiments provide for much faster calculation than direct application of the Kotelnikov (Nyquist-Shannon) theorem. In some embodiments, the calculation may be performed according to the disclosed theorem but, instead of discrete signal convolutions with kernels having different phases, a function series expansion may be used.

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.

A filter processing device that includes an address control unit that specifies, based on the offset amount of a light source frequency and a subcarrier center point for each subcarrier, a write address and a read address for a plurality of items of data included in Fourier transform data based on an optical signal, and a storage unit in which a plurality of items of data are written to the write address specified by the address control unit and in which data is read out from the read address specified by the address control unit. The address control unit specifies the write address and the read address so that compensation for the offset amount and separation of the subcarrier are performed by the same storage unit.

In order to reduce the power consumed when using FFT processing and filtering in the frequency domain together, a digital filter device according to the present invention is provided with: a first filtering means for performing a first fast Fourier transformation using a first data sorting process, first filtering in the frequency domain, a first inverse fast Fourier transformation using a second data sorting process, and overlap removal on a first input block including overlapped data; a second filtering means for performing a second fast Fourier transformation, which simultaneously processes all data in a second input block including overlapped data, second filtering in the frequency domain, a second inverse fast Fourier transformation, which simultaneously processes all received filtered data, and overlap removal; and a data selection means for selecting either the first filtering means or the second filtering means, wherein the operation of the filtering means that is not selected by the data selection means is interrupted.

A phase control signal generation device generating a phase control signal for each of frequency bands for an audio signal converted into a frequency domain, the phase control signal generation device comprising: a setting change means that is able to change setting of a propagation delay time for each of predetermined frequency bands; a difference obtaining means that obtains a difference between propagation delay times before and after setting change; an updating means that updates a phase control amount of the frequency band for which the propagation delay time is changed, based on the obtained difference; and a phase control signal generating means that generates a phase control signal of each frequency band by performing a smoothing process for the phase control amount in a frequency domain using the updated phase control amount.

A communication device includes: a receiving circuit, receiving a plurality of time-domain signals; a transforming circuit, coupled to the receiving circuit, transforming the plurality of time-domain signals to a plurality of frequency-domain signals according to a time-frequency transform operation; a magnitude circuit, coupled to the transforming circuit, performing an absolute value operation on the plurality of frequency-domain signals to generate a plurality of output signals; and a selecting circuit, coupled to the magnitude circuit, selecting a maximum signal that satisfies a check condition from the plurality of output signals.

Provided is a digital filter device that causes the last data of an immediately precedent input block to overlap with the input block of a time domain and generates an overlap block. The overlap block and the immediately precedent input block are each converted into a frequency domain block, subjected to filter processing, and converted into first and second time domain blocks. Among the overlap section of the first time domain block and the second time domain block, the front-end data of the first time domain block and the rear-end data of the temporal axis of the second time domain block are removed as a section of data that is to be removed, and output data is generated. An overlap amount is controlled on the basis of a distortion amount that is determined by comparing the removed section of the data of the first time region domain with the output section of the data of the overlap section of the second time domain block other than the removed section of said overlap section.

This method for the non-linear estimation of no more than two mixed signals from separate sources, the time/frequency representation of which shows an unknown non-zero proportion of zero components, using an array made up of P>2 antennas, when the directional vectors U and V of the sources emitting these signals are additionally known or estimated, includes the following steps: a) Calculating the successive discrete Fourier transforms of the signal received by the antennas and sampled to obtain a time-frequency P-vector grid of the signal; each element of the grid being referred to as a box and containing a complex vector X forming a measurement; b) For each box, calculating the conditional expectation estimator of the signal, or of the signals, from the measurement X and an a priori probability density for the signals that is a Gaussian mixture.