420 results about "Signal compression" patented technology

A method and apparatus provides OFDM signal compression for transfer over serial data links in a base transceiver system (BTS) of a wireless communication network. For the uplink, an RF unit of the BTS applies OFDM cyclic prefix removal and OFDM frequency transformation of the baseband signal samples followed by frequency domain compression of the baseband signal samples, resulting from analog to digital conversion of received analog signals followed by digital downconversion, forming compressed coefficients. After transfer over the serial data link, the baseband processor applies frequency domain decompression to the compressed coefficients prior to further signal processing. For the downlink, the RF unit performs frequency domain decompression of the compressed coefficients and applies OFDM inverse frequency transformation of the decompressed coefficients and OFDM cyclic prefix insertion prior to digital upconversion and digital to analog conversion, generating the analog signal for transmission over the antenna.

A method and apparatus provide signal compression for transfer over serial data links in a base transceiver system (BTS) of a wireless communication network. For the uplink, an RF unit of the BTS applies frequency domain compression of baseband signal samples, resulting from analog to digital conversion of received analog signals followed by digital downconversion, forming compressed coefficients. After transfer over the serial data link, the baseband processor then applies frequency domain decompression to the compressed coefficients prior to normal signal processing. For the downlink, the baseband processor applies frequency domain compression of baseband signal samples and transfers the compressed coefficients to the RF unit. The RF unit applies frequency domain decompression to the compressed coefficients prior to digital upconversion and digital to analog conversion, generating the analog signal for transmission over the antenna. This abstract does not limit the scope of the invention as described in the claims.

Methods and apparatus including a virtual machine and a compression network platform are provided especially for improving the application of compression algorithms and unique identifiers for algorithms, bytecode and HTTP common phrases of HTTP messages utilized to advantage in wireless networks. In particular, a given virtual machine need only identify to a receiving virtual machine the unique identifier for one of an algorithm, a static dictionary or a hash for decompressing a received data signal. Universal decompressor virtual machines may receive uploaded compression algorithms, bytecode identifiers or static dictionary identifiers and the like from proxy call session control functions of a wireless network, the compressing machine or a compression network platform resource which in one embodiment may comprise an IANA database. The methods and apparatus may find particular application in improving the efficiency of presence/group list management.

The invention relates to a compressed sensing reconstructing method of a sparse signal with the unknown block sparsity, belonging to the technical field of compressed sensing, in particular to a reconstruction method of a block sparse signal. The method comprises the steps of finding out one subset of a signal support set by initializing block sparsity k and iterating each block sparse signal, increasing the block sparsity while keeping iteration and finally finding out the support set of the whole source signal x so as to achieve the purpose of reconstructing the source signal x. The invention has high reconstruction precision by iterating and modifying the support set many times, and has high probability for reconstructing block sparse signals without the overmatching phenomenon compared with the traditional block sparsity matching and tracking and orthogonal matching and tracking method. The invention does not need the block sparsity as the priori knowledge and is particularly suitable for the reconstruction field of signals with unknown block sparsity.

A method and an apparatus for an ultrasound system provide compression of ultrasound signal samples after analog to digital conversion and before beamforming. The analog ultrasound signals received from an array of ultrasound transducer elements are digitally sampled by a plurality of analog to digital converters (ADCs) to produce a plurality of sequences of signal samples. Each sequence of signal samples is compressed to form a corresponding sequence of compressed samples. The resulting sequences of compressed samples are transferred via a digital interface to an ultrasound signal processor. At the ultrasound signal processor, the received sequences of compressed samples are decompressed. The typical processing operations, such as beamforming, downconversion and detection, are applied to decompressed samples. This abstract does not limit the scope of the invention as described in the claims.

The present invention extends the generalized Lloyd algorithm (GLA) for vector quantizer (VQ) codebook improvement and codebook design to a new linearly-constrained generalized Lloyd algorithm (LCGLA). The LCGLA improves the quality of VQ codebooks, by forming the codebooks from linear combinations of a reduced set of base codevectors. The present invention enables a principled approach for compressing texture images in formats compatible with various industry standards. New, more flexible compressed texture image formats are also made possible with the present invention. The present invention enhances signal compression by improving traditional VQ approaches through the integrated application of linear constraints on the multiple pattern and signal prototypes that represent a single pattern or block of signal samples.

Control of signal compression is coordinated by selectively modifying control parameters affecting the bit rate, sample rate, dynamic range and compression operations. Selected control parameters are modified according to a control function. The control function can include a ratio parameter that indicates the relative or proportional amounts of change to the control parameters. Alternatively, the control function can be represented in a lookup table with values for the selected control parameters related by the control function. The input signal samples can be resampled according to a sample rate control parameter. The dynamic range of signal samples can be selectively adjusted according to a dynamic range control parameter to form modified signal samples. The resampling and dynamic range adjustment can be applied in any order. The modified signal samples are encoded according to a compression control parameter to form compressed samples. The encoder can apply lossless or lossy encoding.

The invention discloses a sparse sampling and signal compressive sensing reconstruction method. The method comprises: establishing a signal sampling interval of each time, sampling point number, and the number of points recovering, establishing random sparse sampling lower than a Nyquist sampling theorem value; and designing a measurement matrix by random sampling timing sequence values, designing a transformation matrix of a sparse expression domain of signals, determining a compressive sensing matrix, and separated compressive sensing optimizing signal reconstruction in a nonlinear manner. The method is based on rationality of objective world rules, and makes full use of signal sparsity, uses transformation space to describe the signals, and establishes theoretical framework of new signal description and processing, so under the condition that information is not lost is ensured, signals are sampled by speed much lower than required speed of a Shannon's sampling theorem. Simultaneously, signals can be recovered completely, that is, sampling of signals is converted into sampling of information. The invention provides a whole set of complete method. The method can be used in one-dimensional and multidimensional signals, and can process audio frequency, videos, nuclear magnetic resonance, and other signals.

An optimal scanning method for coding/decoding an image signal is provided. In a method of coding an image signal through a discrete cosine transform, at least one is selected among a plurality of reference blocks. A scanning order in which to scan blocks to be coded of the reference blocks is generated and the blocks to be coded are scanned in the order of the generated scanning order. The at least one selected reference block is temporally or spatially adjacent to the block to be coded. When the blocks to be coded are scanned, probabilities that non-zero coefficients occur are obtained from the at least one selected reference block, and the scanning order is determined in descending order starting from the highest probability. Here, the scanning order is generated to be a zigzag scanning order if the probabilities are identical. The optimal scanning method increases signal compression efficiency.

The invention discloses a multi-user collaborative spectrum sensing method based on a single bit compression sensing technology. Based on the current situation of a low actual occupancy rate of wireless spectrum resources, a plurality of control units (CUs) use a single bit complex signal compression sensing technology respectively, after compressed sampling is performed to broadband analog base band signals sent by a master user, the obtained compressed sampling results are transmitted to a financial centre (FC) respectively, and the FC performs collaboration reconstruction to corresponding frequency domain signals of the broadband analog base band signals to obtain occupancy conditions of spectrum resources. Compared with traditional sensing methods, the simplicity of actual quantitative operation is fully considered, the bit speed rate needed by compressed spectrum sensing is further reduced, the computation complexity of each sensing user is reduced, and multi-user collaborative spectrum sensing and single user independent sensing are compared, so that good sensing effects can be obtained.

A signal analyzer and method for measuring signal compression levels of one or more individual orthogonal frequency division multiplexed (OFDM) signals among a plurality of OFDM signals within a composite signal.

An embodiment of the present invention is directed to reducing a memory capacity required for saving compensating data (data used for compensating variations and the like in characteristic of a drive transistor) compared to conventional examples, in a display device. An organic EL display device using an oxide TFT for a drive transistor is provided with: a low pass filter for extracting low frequency component data from pixel current data as data of a drive current of the drive transistor; a first computing portion for obtaining high frequency component data by obtaining a difference between the pixel current data and the low frequency component data; a down-sampling portion for extracting data from the low frequency component data at predetermined sampling intervals; and a high frequency signal compression processing portion for extracting only high amplitude data out of the high frequency component data.

An electronic camera creates image data by performing predetermined signal compression on a still image signal or a moving image signal picked-up and created by an image pickup unit, and records the created image data to a hard disk serving as a main storage medium. The image data is divided into a recording folder or recording file based on the unit of preset recording data capacity and records the divided recording folders or recording files to the hard disk. Each recording folders or recording files are transferred and are recorded to an SD-card serving as a storage medium for transfer, and are copied and recorded to another storage medium by using the SD-card.

The purpose of the present invention is to provide a broadband spectrum sensing method based on differential signal compressed sensing in a cognitive radio system. The method takes energy detection as a basic model and introduces compressed sensing theory to reduce the requirements for analog/digital converters; For the problem of high computational complexity and poor real-time performance in the signal reconstruction process, the detection difference signal is used instead of the signal itself as the basis for spectrum judgment, and accuracy is introduced as the iteration stop condition of the algorithm. The accuracy of the algorithm can be flexibly adjusted according to needs, and the computational complexity can be reduced. The secondary user periodically collects information at a low sampling rate, and retains the information of spectrum detection at time t, which can be used as prior knowledge for detection at time t+1, and the difference signal at two times is used as the input of the reconstruction algorithm , quickly restore the signal characteristics and perform segmental energy detection to obtain the current idle spectrum information of the primary user spectrum, so as to achieve the purpose of real-time low-power broadband spectrum sensing.

Disclosed are scalable quantizers for audio and other signals characterized by a non-uniform, perception-based distortion metric, that operate in a common companded domain which includes both the base-layer and one or more enhancement-layers. The common companded domain is designed to permit use of the same unweighted MSE metric for optimal quantization parameter selection in multiple layers, exploiting the statistical dependence of the enhancement-layer signal on the quantization parameters used in the preceding layer. One embodiment features an asymptotically optimal entropy coded uniform scalar quantizer. Another embodiment is an improved bit rate scalable multi-layer Advanced Audio Coder (AAC) which extends the scalability of the asymptotically optimal entropy coded uniform scalar quantizer to systems with non-uniform base-layer quantization, selecting the enhancement-layer quantization methodology to be used in a particular band based on the preceding layer quantization coefficients. In the important case that the source is well modeled as Laplacian, the optimal conditional quantizer is implementable by only two distinct switchable quantizers depending on whether or not the previous quantizer identified the band in question as a so-called "zero dead-zone:" Hence, major savings in bit rate are recouped at virtually no additional computational cost. For example, the proposed four layer scalable coder consisting of 16 kbps layers achieves performance close to a 60 kbps non-scalable coder on the standard test database of 44.1 kHz audio.

Based on the Internet, such as video surveillance methods, the monitoring nodes, the nodes customer service nodes of these three types of nodes based on the existing Internet component video surveillance network, which is a joint monitoring with the video network devices, the digital video signal compression and coding, through the Internet and video data will be sent directly to customers node; customers nodes is a function of a network terminal equipment, directly through network access control node from the video surveillance data show that after the video decoder; service node is a public IP address with the network equipment to assist customers nodes and monitoring network nodes to establish direct links, so as to achieve control nodes directly with the client node data exchange. This invention does away with the existing network video monitoring system in the video server performance bottlenecks, a client node and control nodes, and so on (peer to peer) direct data exchange program, which completely resolve the existing video surveillance technology can not solve the contradiction.

An apparatus and method for compression and expansion of a wave signal on a time axis. A memory device stores waveform data representative of a waveform for each sub-frequency band of each main-frequency band of a wave signal, in which the wave signal is divided into a plurality of the main-frequency bands, each of the main-frequency bands is divided into a plurality of the sub-frequency bands. A plurality of time axis compression and expansion devices are provided for each of the sub-frequency bands for performing time axis compression and expansion of the waveform. A mixing device mixes signals provided from the time axis compression and expansion devices. Each of the time axis compression and expansion devices performs compression and expansion in a sampling rate that corresponds to one of the main-frequency bands that includes the sub-frequency band that is subject to the waveform time axis compression and expansion, wherein the sampling rate of at least one of the main-frequency bands is different from the sampling rate of at least one other of the main frequency bands.

The invention provides a compressed sensing-based antifriction bearing fault diagnosis method based on a working condition disturbance condition. The antifriction bearing fault diagnosis method comprises signal compression, front fault diagnosis and a far-end signal reconstruction algorithm. The method utilizes a vibration signal of a bearing to perform fault diagnosis. Based on the compressed sensing theory, a measuring matrix is constructed and compression of vibration signals is realized so that the transmission bandwidth consumption of the vibration signals of the bearing is effectively reduced. The on-board fault diagnosis part utilizes the compression reference matrix, the matching pursuit algorithm to realize fault diagnosis under the working condition disturbance condition through the reconstruction matching method. Based on the on-board fault diagnosis, the far-end signal reconstruction can be realized through the reconstruction matching method so that fault diagnosis enhancement and performance assessment of the far end can be realized. The method system is complete and is suitable for the working condition disturbance condition, and is high in the accuracy of fault diagnosis and is high in engineering practicality.

This invention relates to wireless data collection and process method and system, which orderly comprises data adjuster, analogue low pass filter, A/D converter, main processor, wireless communication module and receive antenna and memory connected to main processor and power module with power parts. The method comprises the following steps: adjusting digital signal form digital filtering and processing analogue low pass filter converted into digital signals; after filtering on digital signal and processing time zone signal compression and property extracting to realize wireless receive and send of data.

An envelope based amplitude mapping achieves the signal compression required to provide a natural sound level without the high processor loading or waveform alteration. In a preferred embodiment, the output of a family of parallel bandpass filters is processed by an envelope detector, followed by decimation. The resulting reduced data rate envelope is log mapped to produce a scaling factor for the original high data rate bandpass filter output sequence. The resulting scaled signal determines the current level for stimulation of the cochlea for each frequency band, which stimulation achieves a log mapping of the sound amplitude effect similar to natural hearing, while reducing processor load, and preserving waveform shape.