75 results about "Sinc function" patented technology

A method converts a resolution of video signals, the method including: calculating up-sampling and down-sampling ratios based on a resolution of an input video signal and a desired resolution of an output video signal; calculating a number of filter tabs by multiplying the up-sampling and down-sampling ratios by a number of side lobes; calculating first filter coefficients of a same number of the filter tabs by multiplying a window function by a sinc function; calculating final filter coefficients by subtracting a result of a multiplication of a Gaussian function by a window function from the first filter coefficients, and then normalizing the final filter coefficients; and performing filtering in vertical and horizontal directions based on the final filter coefficients by modifying a sampling rate of an input video signal depending on the up-sampling and down-sampling ratios, to obtain clear video images.

A communication system (10) includes a transmitting unit (12) with a peak to average power (PAPR) reduction section (30). The PAPR reduction section (30) modifies the PAPR reduction it effects in a communication signal (14) in accordance with two different error vector magnitude (EVM) constraints for each channel type (102), where a channel type (102) is a distinct combination of a modulation order and a coding rate. The EVM constraint followed for each subcarrier (25) in an OFDM or OFDMA application is selected in response to whether the subcarrier (25) conveys voice or non-voice data. The PAPR reduction section (30) may include a scaling filter (72). The scaling filter (72) is efficiently defined through the use of a predetermined sinc function (94) and a first stage scale factor (67) that is calculated in response to a weighted average of excursion signal subcarrier gains (150), where the weighting follows the distribution of channel types (102) through the subcarriers (25).

A method converts a resolution of video signals, the method including: calculating up-sampling and down-sampling ratios based on a resolution of an input video signal and a desired resolution of an output video signal; calculating a number of filter tabs by multiplying the up-sampling and down-sampling ratios by a number of side lobes; calculating first filter coefficients of a same number of the filter tabs by multiplying a window function by a sinc function; calculating final filter coefficients by subtracting a result of a multiplication of a Gaussian function by a window function from the first filter coefficients, and then normalizing the final filter coefficients; and performing filtering in vertical and horizontal directions based on the final filter coefficients by modifying a sampling rate of an input video signal depending on the up-sampling and down-sampling ratios, to obtain clear video images.

A charge domain filter device includes a SINC filter with a frequency characteristic expressed by a SINC function, and a bandpass filter connected to an output end of the SINC filter and having a frequency characteristic with a particular center frequency.

A method of calculating an aerial image of a spatial light modulator array includes calculating a pixel interference matrix that represents pair wise interference between pixels of the spatial light modulator array; calculating effective graytones corresponding to modulation states of the pixels; and calculating the aerial image based on the pixel interference matrix and the effective graytones. The graytones depend only on the modulation states of the pixels. The pixel interference matrix depends only on position variables. The position variables are position in an image plane and position in a plane of a source of electromagnetic radiation. The pixel interference matrix can be a matrix of functions. The pixel interference matrix can be a four dimensional matrix. The effective graytones are approximated using sinc functions, or using polynomial functions.

A charge domain filter device includes a SINC filter with a frequency characteristic expressed by a SINC function, and a bandpass filter connected to an output end of the SINC filter and having a frequency characteristic with a particular center frequency.

The invention belongs to the radar signal processing technology field and discloses a target parameter estimation method based on an FDA-MIMO radar. The method comprises the following steps of designing a frequency increment resulting in wave beam coupling and an array element spacing, breaking linearly increasing synchronization between the two, achieving a decoupling effect, and providing a condition for unique estimation of a target distance angle; and through designing, making the frequency increment of each array element satisfy a sinc function increasing relation, and then carrying outangle and distance estimation to obtain an accurate target angle and distance information. By using the method of the invention, coupling of an emission wave beam at a distance-angle can be solved. When the distances and the angles of multiple targets are different, the distance and the angle of the target is well estimated to avoid occurrence of false targets, and estimation performance of the radar is improved.

The invention provides a spaceborne synthetic aperture radar reference function acquiring method based on internal scaling data. The method comprises the following steps of 1, acquiring amplitude phase error data of an internal scaler full-array-plane received-and-transmitted scaling pathway, an antenna scaling network and an antenna sub-array; 2, acquiring full-array-plane received-and-transmitted scaling data of a radar system on the condition of a preset working bandwidth and pulse width parameter; and 3, compensating amplitude phase error of the internal scaler, the scaling network and the antenna sub-array in the full-array-plane received-and-transmitted scaling data and the like. According to the method of the invention, on the condition of relatively high characteristic consistency between a radar received-and-transmitted copying signal and an actual received-and-transmitted signal, a reference function is used for performing coupling processing, thereby obtaining an effect which is approximate to a standard sinc function, and realizing most powerful supplementing and improvement to predistortion processing of the radar system. The spaceborne synthetic aperture radar reference function acquiring method is suitable for subsequent all radar microwave loads with a full-array-plane received-and-transmitted scaling mode and settles a problem of relatively high influence of radar system amplitude phase error to an imaging performances. Furthermore the method has a remarkable effect for improving imaging performance of the radar system.

A communication system includes a transmitting unit with a peak to average power (PAPR) reduction section. The PAPR reduction section modifies the PAPR reduction it effects in a communication signal in accordance with two different error vector magnitude (EVM) constraints for each channel type, where a channel type is a distinct combination of a modulation order and a coding rate. The EVM constraint followed for each subcarrier in an OFDM or OFDMA application is selected in response to whether the subcarrier conveys voice or non-voice data. The PAPR reduction section may include a scaling filter. The scaling filter is efficiently defined through the use of a predetermined sinc function and a first stage scale factor that is calculated in response to a weighted average of excursion signal subcarrier gains, where the weighting follows the distribution of channel types through the subcarriers.

A rotating induction machine, containing five or more different phases, having windings distributed according to a sinc function with a cutoff frequency allowing low-order spatial harmonics but preventing higher order spatial harmonics from flowing. In a preferred embodiment, the machine is connected to drive means capable of injecting third harmonic into the machine. In a further preferred embodiment, the windings are connected to the drive means with a mesh connection and the machine has five phases.

A digital processing technique for measuring the time of arrival of a digitized electronic signal pulse for in-line implementation in a field programmable gate array or digital signal processor. For each detected pulse, an interpolation method is used to estimate its maximum M, M is multiplied by a fraction f, and a second interpolation method is used to estimate the time when the pulse reaches the value f·M, which is then taken as the pulse's time of arrival. Various interpolation methods may be used. A particularly accurate method employs convolution of the pulse data by a kernel that is the product of the sinc function and a Gaussian. Detector physics limited time resolutions of 2-5% of the sampling interval are demonstrated. Estimating M is useful in its own right for determining pulse amplitudes, for example as a measure of the energies of photons absorbed in a detector.

The invention provides a resolution performance evaluation method for a digital X-ray imaging system. The method comprises the steps that (1) a plurality of incision images are continuously collected; (2) superposition averaging is performed on the collected incision images, afterwards, incision boundary detection is performed on the averaged incision images, and an incision boundary straight line is obtained through line fitting; (3) an incision tilt angle is obtained, and an oversampling ESF curve is constructed; (4) the oversampling ESF curve is de-noised by the adoption of a monotonic curve fitting method; (5) a suitable translation distance is selected, a real ESF curve and a difference curve of a translation distance result of the real ESF curve are constructed, and Fourier transform is performed on the real ESF curve and the difference curve to obtain sinc functions; (6) suitable translation is performed on an actual oversampling ESF curve, and then subtraction is performed between the actual oversampling ESF curve and the original oversampling ESF curve to obtain a symmetrical oversampling curve; (7) a system modulation transfer function is solved through a deterioration model formula under a frequency domain. According to the resolution performance evaluation method, compared with a traditional incision measuring method, a more accurate MTF curve can be obtained.

A synthetic aperture processing system that includes a signal transmission unit for generating and radiating a plurality of chirp waves to an irradiation region from measuring sites, a signal reception unit for receiving a plurality of reflected waves caused by the plurality of chirp waves, a range compression unit for range-compressing each of the reflected waves and generating reception data consisting of sinc functions, a cross-correlation computation unit for, based on a plurality of model data segments, calculating correlation values representing a degree of correlation between each of the model data segments and the reception data, and image output unit for outputting the correlation values calculated by cross-correlation computation unit.