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4363 results about "Target signal" patented technology

Methods and Devices for Low-Frequency Emphasis During Audio Compression Based on Acelp/Tcx

A first aspect of the present invention relates to a method for low-frequency emphasizing the spectrum of a sound signal transformed in a frequency domain and comprising transform coefficients grouped in a number of blocks, in which a maximum energy for one block is calculated and a position index of the block with maximum energy is determined, a factor is calculated for each block having a position index smaller than the position index of the block with maximum energy the calculated maximum energy and the energy of the block, and, for each block, a gain determining from the factor is applied to the transform coefficients of the block. Another aspect of the invention is concerned with an HF coding method for coding, through a bandwidth extension scheme, an HF signal obtained from separation of a full-bandwidth sound signal into the HF signal and a LF signal, in which an estimation of the an HF gain is calculated from LPC coefficients, the energy of the HF signal is calculated, the LF signal is processed to produce a synthesized version of the HF signal, the energy of the synthesized version of the HF signal is calculated, a ratio between the energy of the HF signal and the energy of the synthesized version of the HF signal is calculated and expressing as an HF gain, and a difference between the estimation of the HF gain and the HF gain is calculated to obtain a gain correction. A third aspect of the invention is concerned with a method for producing from a decoded target signal an overlap-add target signal in a current frame coded according to a first coding mode. According to this method, the decoded target signal of the current frame is windowed and a left portion of the window is skipped. A zero-input response of a weighting filter of the previous frame coded according to a second coding mode is calculated and windowed so that the zero-input response has an amplitude monotonically decreasing to zero after a predetermined time period. Finally, the calculated zero-input response is added to the decoded target signal to reconstruct the overlap-add target signal.
Owner:VOICEAGE CORP

Methods and devices for low-frequency emphasis during audio compression based on ACELP/TCX

A first aspect of the present invention relates to a method for low-frequency emphasizing the spectrum of a sound signal transformed in a frequency domain and comprising transform coefficients grouped in a number of blocks, in which a maximum energy for one block is calculated and a position index of the block with maximum energy is determined, a factor is calculated for each block having a position index smaller than the position index of the block with maximum energy the calculated maximum energy and the energy of the block, and, for each block, a gain determining from the factor is applied to the transform coefficients of the block. Another aspect of the invention is concerned with an HF coding method for coding, through a bandwidth extension scheme, an HF signal obtained from separation of a full-bandwidth sound signal into the HF signal and a LF signal, in which an estimation of the an HF gain is calculated from LPC coefficients, the energy of the HF signal is calculated, the LF signal is processed to produce a synthesized version of the HF signal, the energy of the synthesized version of the HF signal is calculated, a ratio between the energy of the HF signal and the energy of the synthesized version of the HF signal is calculated and expressing as an HF gain, and a difference between the estimation of the HF gain and the HF gain is calculated to obtain a gain correction. A third aspect of the invention is concerned with a method for producing from a decoded target signal an overlap-add target signal in a current frame coded according to a first coding mode. According to this method, the decoded target signal of the current frame is windowed and a left portion of the window is skipped. A zero-input response of a weighting filter of the previous frame coded according to a second coding mode is calculated and windowed so that the zero-input response has an amplitude monotonically decreasing to zero after a predetermined time period. Finally, the calculated zero-input response is added to the decoded target signal to reconstruct the overlap-add target signal.
Owner:VOICEAGE CORP

Methods and devices for low-frequency emphasis during audio compression based on ACELP/TCX

A first aspect of the present invention relates to a method for low-frequency emphasizing the spectrum of a sound signal transformed in a frequency domain and comprising transform coefficients grouped in a number of blocks, in which a maximum energy for one block is calculated and a position index of the block with maximum energy is determined, a factor is calculated for each block having a position index smaller than the position index of the block with maximum energy the calculated maximum energy and the energy of the block, and, for each block, a gain determining from the factor is applied to the transform coefficients of the block. Another aspect of the invention is concerned with an HF coding method for coding, through a bandwidth extension scheme, an HF signal obtained from separation of a full-bandwidth sound signal into the HF signal and a LF signal, in which an estimation of the an HF gain is calculated from LPC coefficients, the energy of the HF signal is calculated, the LF signal is processed to produce a synthesized version of the HF signal, the energy of the synthesized version of the HF signal is calculated, a ratio between the energy of the HF signal and the energy of the synthesized version of the HF signal is calculated and expressing as an HF gain, and a difference between the estimation of the HF gain and the HF gain is calculated to obtain a gain correction. A third aspect of the invention is concerned with a method for producing from a decoded target signal an overlap-add target signal in a current frame coded according to a first coding mode. According to this method, the decoded target signal of the current frame is windowed and a left portion of the window is skipped. A zero-input response of a weighting filter of the previous frame coded according to a second coding mode is calculated and windowed so that the zero-input response has an amplitude monotonically decreasing to zero after a predetermined time period. Finally, the calculated zero-input response is added to the decoded target signal to reconstruct the overlap-add target signal.
Owner:VOICEAGE CORP

Accurate target detection system

An accurate target detection system. The system includes a sensor (22) that receives electromagnetic signals and provides electrical signals in response thereto. A non-uniformity correction circuit (28, 38, 52) corrects non-uniformities in the sensor (22) based on the electrical signals and provides calibrated electrical signals in response thereto. A third circuit (30, 32, 34, 38, 42, 44, 52) determines if a target signal is present within the calibrated electrical signals and provides a target detection signal in response thereto. A fourth circuit (38, 40, 48) selectively activates or deactivates the non-uniformity correction circuit (28, 38, 52) based on the target detection signal. In a specific embodiment, the sensor (22) is an array of electromagnetic energy detectors (22), each detector providing an electrical detector output signal The non-uniformity correction circuit (28, 38, and 52) includes circuit for compensating for gain, background, and noise non-uniformities (28, 38, and 52) in the electromagnetic energy detectors. The non-uniformity correction circuit (28, 38, and 52) includes a detector gain term memory (28) for storing detector gain compensation values. The detector gain compensation values are normalized by noise estimates unique to each of the detectors. The third circuit (30, 32, 34, 38, 42, 44, and 52) includes a signal enhancement circuit for reducing noise (34, 42) in the calibrated electrical signals. The third circuit (30, 32, 34, 38, 42, 44, and 52) includes a noise estimation circuit (32, 38) that estimates noise in each of the detector output signals and provides noise estimates in response thereto. The noise estimation circuit (32, 38) further includes a noise estimator circuit (38) and a recursive background estimator (32). The third circuit (30, 32, 34, 38, 42, 44, 52) further includes a subtractor (30) for subtracting background from the calibrated electrical signals and providing background subtracted signals in response thereto. The signal enhancement circuit (34, 42) includes a frame integrator circuit for adding frames of image data (34), each frame containing data corresponding to the background subtracted signals and providing summed frames in response thereto. The third circuit (30, 32, 34, 38, 42, 44, 52) includes a first threshold circuit (44) for comparing the filtered signal to a first threshold and a second threshold and providing a threshold exceedance signal if the filtered signal is between the first threshold and the second threshold.
Owner:RAYTHEON CO

Phased array digital multi-beam forming machine for electron reconnaissance

The invention discloses a phased array digital multi-beam generator for electronic reconnaissance, for the high resolution direction measurement having strong and weak signals or coherent multi signals, and forming the multi-target signal into anti-interference digital multi-beam to form a multi-beam process: first, in a data acquisition pretreatment board, an AD samples intermediate frequency analogue real signals output by each array antenna receiver, a DPS and a FPGA chip are cooperated to complete quadrate sampling and amplitude phase error correction; the intermediate frequency analogue actual signals are converted into a baseband digital complex signal and the amplitude phase error between the multi channels is corrected; a LVDS channel transmits the baseband digital complex signal to a signal processing board, the DPS completes the high resolution direction measurement having strong and weak signals or coherent multi signals and calculates the weight value group formed by the adaptive beam; the weight value group is added into the wave beam in the signal processing board FPGA to form a network; completing forming anti-interference digital multi-beam of the multi-target signal; an up frequency converter converts the output of the anti-interference digital multi-beam into needed intermediate frequency analogue signal.
Owner:XIDIAN UNIV

Multi-fractal detection method of targets in FRFT (Fractional Fourier Transformation) domain sea clutter

ActiveCN102967854AReduce the demand for signal-to-clutter ratio in target detectionThe need to reduce the signal-to-clutter ratioWave based measurement systemsTime domainTarget signal
The invention discloses a multi-fractal detection method of targets in FRFT (Fractional Fourier Transformation) domain sea clutter and belongs to the radar signal processing field. According to the conventional multi-fractal detection methods of targets in sea clutter, echo sequences in the radar time domain are processed directly, and therefore detection performance of weak moving targets in strong sea clutter background is poor. The multi-fractal detection method of targets in FRFT domain sea clutter is characterized in that fractional Fourier transformation is organically combined with the multi-fractal processing method, and the generalized Hurst index number of the sea-clutter fractional Fourier transformation spectrum is extracted to form detection statistics by comprehensively utilizing the advantage that the fractional Fourier transformation is capable of effectively improving the signal to clutter ratio of the moving target on the sea surface and the feature that the multi-fractal characteristic is capable of breaking the tether of the signal to clutter ratio to a certain extent. The detection method comprehensively utilizes the advantages of phase-coherent accumulation and multi-fractal theory and has excellent separating capability on the weak moving targets in sea clutter; and simultaneously, the method is also suitable for tracking target signals in nonuniform fractal clutter and has popularization and application values.
Owner:NAVAL AERONAUTICAL & ASTRONAUTICAL UNIV PLA

General signal generator for radar target simulation

The invention, which relates to the technical field of the radar target simulation, discloses a general signal generator for radar target simulation. With the signal generator, a defect that the existing radar target signal generator is based on a special-purpose signal generator and only serve a radar system with a specific type in terms of frequency band coverage and function setting and thus the application range is limited can be solved. The signal generator comprises an embedded main control computer, a timing sequence control unit, an attenuation drive, a local oscillation module, a filtering, amplifying and limiting amplitude power divider, a plurality of digital radio frequency storage and playback modules, a plurality of Doppler frequency simulation modules, a radar cross section control module, a noise modulation module, a microwave down mixer, and IQ up mixing unit and the like. The output terminal of the microwave down mixer is connected with the filtering, amplifying and limiting amplitude power divider; the multiple digital radio frequency storage and playback modules are connected to the filtering, amplifying and limiting amplitude power divider; and the output terminal of each digital radio frequency storage and playback module is connected with one Doppler frequency simulation module.
Owner:THE 41ST INST OF CHINA ELECTRONICS TECH GRP
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