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219 results about "Inverse filter" patented technology

In signal processing, for a filter g, an inverse filter h is one such that the sequence of applying g then h to a signal results in the original signal. Software or electronic inverse filters are often used to compensate for the effect of unwanted environmental filtering of signals.

Equalizer circuit, communication system, and method that is adaptive to varying launch amplitudes for reducing receiver error

A transmission line equalizer, communication system, and method are provided for adaptively compensating for changes in transmission path length and transmission path medium. Within the equalizer is a filter that exhibits a high pass characteristic and, more specifically, has an inverse frequency response to that of the transmission path. The inverse filter can include a pair of amplifier stages coupled in parallel, with a mixer chosen to adaptively select portions of one stage over than of the other. The dual stage inverse filter can, therefore, adapt to greater transmission path lengths and/or attenuation. A feedback architecture is used to set the inverse filter response by measuring the amplitude of a communication signal output from the inverse filter during periods of low frequency. A peak detector will capture a peak-to-peak voltage value during those periods, and adjust the output of the slicer to match a launch amplitude of the communication signal. The peak detector within the feedback architecture helps ensure the predicted amplitude matches the launch amplitude to minimize over-compensation or under-compensation even though a different integrator might register no difference in integrated voltage or energy at the output of the inverse filter compared to the output of the slicer.
Owner:RPX CORP

Method and apparatus for faster-than-real-time lossless compression and decompression of images

The present invention is a method and apparatus for compressing and decompressing data. In particular, the present invention provides for (de-)compressing naturalistic color-image and moving-image data, including high-precision and high-definition formats, with zero information loss, one-sample latency and in faster than real time on common computing platforms, resulting in doubled transmission, storage, and playback speed and doubled transmission bandwidth and storage capacity, and hence in doubled throughput for non-CPU-bound image-editing tasks in comparison with uncompressed formats. The present invention uses a nearly symmetrical compression-decompression scheme that provides temporal, spatial, and spectral compression, using a reversible condensing/decondensing filter, context reducer, and encoder/decoder. In the preferred embodiment of the invention, the compression filter is implemented as a cascade of quasilinear feedforward filters, with temporal, multidimensional spatial, and spectral stages, where appropriate, in that order, whose support consists of adjacent causal samples of the respective image. The decompressor cascades quasilinear feedback inverse filters in the reverse order. The filters can be implemented with mere integer addition, subtraction, and either one-dimensional table lookup or constant multiplication and binary shifting, depending on the computing environment Tables permit the data precision to be constrained throughout to that of the image samples. The encoder uses a table of prefix codes roughly inversely proportional in length to their probability, while the decoder uses chunked decode tables for accelerated lookup. In the fastest and simplest mode, the code tables are context-independent. For greater power, at the cost of a reduction in speed, the code tables are based on the temporal, multidimensional spatial, and spectral adjacent causal residue samples, where contexts with similar probability distributions are incoherently collapsed by a context reducer using one-dimensional lookup tables followed by implicitly multidimensional lookup tables, to minimize the overall table size. The invention's minimal resource requirements makes it ideal for implementation in either hardware or software.
Owner:WITTENSTEIN ANDREAS

A depression auxiliary detection method based on acoustic characteristics and sparse mathematics and a classifier

The invention belongs to the technical field of speech processing and image processing and discloses a depression auxiliary detection method based on acoustic characteristics and sparse mathematics and a classifier. The method is characterized by carrying out depression diagnosis based on speech and facial emotion common identification; realizing estimation of a glottis signal through an inverse filter; carrying out global analysis on the speech signals to extract characteristic parameters, and analyzing timing and distribution features of the characteristic parameters to find out rhyme rulesof speeches in different emotions as basis of emotion recognition; using MFCC as a speech signal to be processed for analysis of the characteristic parameters, collecting data in records through a plurality of groups of training data, and establishing a neural network model for diagnosis; through an OMP-based sparse express algorithm, obtaining sparse linear combination of a test sample; and carrying out judgment and classification on facial emotions, and carrying out linear combination on the obtained result and the speech recognition result to obtain final probability for expressing each data. The depression recognition rate is improved greatly, and the cost is low.
Owner:NORTHWEST UNIV +1

Enhancement of speech coding in background noise for low-rate speech coder

A speech coding system employs measurements of robust features of speech frames whose distribution are not strongly affected by noise / levels to make voicing decisions for input speech occurring in a noisy environment. Linear programing analysis of the robust features and respective weights are used to determine an optimum linear combination of these features. The input speech vectors are matched to a vocabulary of codewords in order to select the corresponding, optimally matching codeword. Adaptive vector quantization is used in which a vocabulary of words obtained in a quiet environment is updated based upon a noise estimate of a noisy environment in which the input speech occurs, and the "noisy" vocabulary is then searched for the best match with an input speech vector. The corresponding clean codeword index is then selected for transmission and for synthesis at the receiver end. The results are better spectral reproduction and significant intelligibility enhancement over prior coding approaches. Robust features found to allow robust voicing decisions include: low-band energy; zero-crossing counts adapted for noise level; AMDF ratio (speech periodicity) measure; low-pass filtered backward correlation; low-pass filtered forward correlation; inverse-filtered backward correlation; and inverse-filtered pitch prediction gain measure.
Owner:HARRIS CORP

Device and method for identifying inverse characteristic of nonlinear system, power amplifier and predistorter thereof

The invention discloses a nonlinear system, in particular a device and a method for identifying inverse characteristic of a nonlinear power amplifier, a predistorter of the power amplifier and power amplification equipment using the device for identifying the inverse characteristic of the nonlinear system and the predistorter. The method for identifying the inverse characteristic of the nonlinear system according to an original input signal x(n) and a corresponding feedback output signal y<G>(n) of the nonlinear system comprises the following steps: according to an inverse filter signal x<F> (n) and the feedback output signal y<G>(n), calculating an inquiry form function Q[.]; according to the feedback output signal y<G>(n) and the inquiry form function Q[.], generating a middle predistortion signal z(n); according to the middle predistortion signal z(n) and the original input signal x(n), constructing a filter function F[.]; carrying out inverse filtering on the original input signal x(n) by using parameters of the filter function F[.] to generate an inverse filter signal x<F>(n); repeating each step through iteration till meeting the set condition, wherein the inquiry form function Q[.] and the filter function F[.] represent the inverse characteristic of the nonlinear system.
Owner:FUJITSU LTD

Sidewalk pavement structure for water permeation, water storage and water discharging

The invention discloses a sidewalk pavement structure for water permeation, water storage and water discharging. The sidewalk pavement structure comprises a sidewalk, a roadway and a rainwater port communicated with a municipal water discharging system and further comprises a transverse water permeation pipe, the sidewalk comprises a water-permeable surface layer, a water-permeable leveling layer, a water-permeable base layer and an inverse filtering cushion which are arranged sequentially from top to bottom, a groove paved with a filling material is formed in the bottom of the inner side of the inverse filtering cushion, and waterproof geotechnical cloth is arranged at the bottom of the inverse filtering cushion, on the left and right sides of the groove and at the bottom of the groove; first kerbs are arranged on two sides of the sidewalk, and the transverse water permeation pipe communicates the groove with the rainwater port. The sidewalk pavement structure has good water permeating, storing and discharging functions, can effectively prevent water accumulation on the surface of the sidewalk and can relieve pressure of the municipal water discharging system under extreme raining conditions to certain extent; rainwater is avoided permeating into roadbeds, so that long-time stability of the roadbeds is guaranteed; water permeability and air permeability of the sidewalk pavement structure can be improved, and urban 'heat island effect' is relieved to certain content.
Owner:中国市政工程西北设计研究院有限公司
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