136 results about "Distortion reduction" patented technology

A method and apparatus to achieve relatively high quality audio data compression / decompression, while achieving relatively low bit rates (e.g., high compression ratios). According to one aspect of the invention, a residual signal is subband decomposed and adaptively quantized and encoded to capture frequency information that may provide higher quality compression and decompression relative to transform encoding techniques. According to a second aspect of the invention, an input audio signal is compared to an encoded signal based on the input audio signal to detect and reduce, as necessary, distortion in the encoded signal or portions thereof.

For sample adaptive offset, classification may be used to classify the pixels into multiple categories and pixels in each category are offset compensated using an offset value for the category. The classification may be based on values of the current pixel and its neighboring pixels before SAO compensation. Therefore, the SAO compensated pixel cannot be written back to the current pixel location until the category for all pixels are determined. An embodiment of the present invention stores the relation between the current pixel and said one or more neighboring pixels so that the SAO compensated current pixel can replace the current pixel without buffering the to-be-processed pixels for classification. The SAO process may be performed on a region by region basis to adapt to the local characteristics of the picture. Rate-distortion optimization (RDO) is often used to guide the mode decision, such as region splitting / region merging decision. Computations associated with the RDO process usually are very computational intensive. Accordingly, distortion reduction estimation is developed which can substantially reduce the required computation associated with RDO.

A linearizer reduces nonlinear intermodulation distortion in radio frequency and microwave systems by first directly generating in-phase and quadrature nonlinear intermodulation products of the system input. Controllable amounts of each phase are then added back into the system such that the vector sum of nonlinear intermodulation products at the output is reduced or eliminated by destructive interference, while the fundamentals are substantially unaffected. The quadrature distorted signals are generated with two lightly-biased and thus overdriven differential pairs having gain-determining degeneration impedances that are in quadrature with each other. The amount of each quadrature phase summed to the output is controlled with electronically tunable four-quadrant variable attenuators. The quadrature phasing enables rapidly convergent tuning to minimize distortion using conventional scalar spectral analysis. The advantages of a linearizer using rectangular vector coordinate system are significant.

An integrated receiver with channel selection and image rejection substantially implemented on a single CMOS integrated circuit. A receiver front end provides programmable attenuation and a programmable gain low noise amplifier. LC filters integrated onto the substrate in conjunction with image reject mixers provide image frequency rejection. Filter tuning and inductor Q compensation over temperature are performed on chip. Active filters utilize multi track spiral inductors with shields to increase circuit Q. The filters incorporate a gain stage that provides improved dynamic range through the use of cross coupled auxiliary differential pair CMOS amplifiers to cancel distortion in a main linearized differential pair amplifier. Frequency planning provides additional image rejection. Local oscillator signal generation methods on chip reduce distortion. A PLL generates needed out of band LO signals. Direct synthesis generates in band LO signals. PLL VCOs are centered automatically. A differential crystal oscillator provides a frequency reference. Differential signal transmission throughout the receiver is used. ESD protection is provided by a pad ring and ESD clamping structure. Shunts utilize a gate boosting at each pin to discharge ESD build up. An IF VGA utilizes distortion cancellation achieved with cross coupled differential pair amplifiers having their Vds dynamically modified in conjunction with current steering of the differential pairs sources.

The present invention provides a technique for cancellation of jammer signals in a radio frequency receiver. A radio frequency signal contains both a desirable signal and an undesirable jammer signal. The combined signal is processed with a filter (104) to extract only the undesirable jammer signal. The jammer signal is then added (104) back to the combined signal to effectively cancel the jammer signal. The system may be implemented using a feedforward approach or a feedback approach. The resultant clean signal is processed in a conventional manner.

The present invention relates to a control system for a vibrator system capable of generating and applying a reciprocating force to an object, such as the underlying ground or water. The control system is generally provided with a means for outputting a drive signal having a fundamental frequency to the vibrator system to activate the reciprocating of the base plate of the vibrating system and a means for receiving a vibrator output signal indicative of the force applied to the object. The vibrator output signal includes at least one harmonic frequency signal and is delayed with respect to the phase of the initial drive signal. To increase the signal-to-noise ratio of the vibrator system, the control system includes a harmonic distortion reduction means receiving the vibrator output signal for outputting at least one harmonic drive signal to the vibrator system. The harmonic drive signal has a proper phase, amplitude, polarity, and frequency which are adjusted to minimize at least one of the harmonic frequency signals being produced by the vibrator system.

A picture signal processing method and apparatus in which the block distortion or the mosquito noise generated on picture compression / expansion using block encoding or the like is removed and picture quality correction such as contour enhancement is carried out effectively. Compression-encoded picture signals are expanded and decoded by a MPEG decoder 106 and the decoded picture signals are sent to a noise reducing circuit 107. The noise reducing circuit 107 reduces the noise by block distortion reduction or by field recursive type noise reduction. The resulting noise-reduced or noise-freed picture signals are sent to a picture quality correction circuit 108, which then performs picture quality correction, such as contour enhancement.

A method and system for providing a mixed-mode (current- and voltage-source) audio amplifier is disclosed. The mixed-mode amplifier includes a voltage sensing feedback path including a first network comprising at least one circuit; and a current sensing feedback path including a second network comprising at least one circuit. According to the method and system disclosed herein, the first and second networks vary an output impedance or transconductance of the amplifier as a function of frequency of the input voltage signal, such that at a first frequency range, the amplifier operates substantially as a current amplifier, and at a second frequency range, the amplifier operates substantially as a voltage amplifier, thereby inheriting distortion reduction of the current amplifier and stability of the voltage amplifier.

A sound producing system includes a loudspeaker to generate an audible signal. A transducer generates a pressure feedback signal from the audible signal. A controller produces a controlled signal for application to the loudspeaker. The controller derives the controlled signal from the pressure feedback signal and an audio input signal. The controlled signal improves the Sound Pressure Level (SPL) frequency response and reduces distortion within a selected bandwidth of the loudspeaker.

The present invention provides a technique for cancellation of jammer signals in a radio frequency receiver. A radio frequency signal contains both a desirable signal and an undesirable jammer signal. The combined signal is processed with a filter (104) to extract only the undesirable jammer signal. The jammer signal is then added (104) back to the combined signal to effectively cancel the jammer signal. The system may be implemented using a feedforward approach or a feedback approach. The resultant clean signal is processed in a conventional manner.

A method for encoding rate-distortion information associated with the compression of an input digital image includes the steps of: computing rate and distortion-reduction values associated with each coding pass of each compressed codeblock bit-stream, and encoding rate and distortion-reduction values associated with coding passes contained in the final compressed bit-stream. A method for using encoded rate-distortion information associated with a compressed digital image bit-stream during transcoding of said compressed digital image bitstream includes the steps of: parsing the compressed digital image bit-stream to obtain compressed codeblock bit-streams, decoding the encoded RD information to obtain rate and distortion-reduction values associated with codeblock coding passes, and using such rate-distortion information to optimally transcode such compressed digital image bit-stream to form a new compressed digital image bit-stream at a given bit-rate, resolution, and for given visual weights.

A method of processing a signal is disclosed. The method comprises generating a digital signal, converting the digital signal to an analog signal, and generating an amplified analog signal having distortions. The method further comprises converting the amplified analog signal to a feedback digital signal at a sample rate and updating a model of the distortions based on the feedback digital signal.

An optical assembly for optical aperture expansion combines facet reflective technology with diffractive technology. At least two diffractive components having opposite optical power (matching) are used, so that chromatic dispersion introduced by the first diffractive component will then be cancelled by the second diffractive component. The two diffractive components are used in combination with a reflective optical component to achieve more efficient aperture expansion (for near eye display), reducing distortions and noise, while also reducing design constraints on the system and individual components, as compared to conventional techniques. The assembly eliminates and / or reduces the need for polarization management, while enabling wider field of view. In addition, embodiments can have reduced nonuniformity, as compared to conventional single technology implementations, since the distortion patterns of the two technologies do not correlate.

In one embodiment, an algorithm dynamically selects a method for reducing distortion in a multi-carrier modulated signal, such as an orthogonal frequency division multiplexing (OFDM) signal. The algorithm directs a transmitter to transmit peak-to-average power ratio (PAPR)-reduction signals over reserved tones (i.e., frequencies) if reserved tones are available. If reserved tones are not available, then the algorithm directs the transmitter to transmit PAPR-reduction symbols over free tones if free tones are available. If the free tones for this transmitter are used by adjacent transmitters, then interference-reduction techniques may be used to reduce interference with the adjacent transmitters. If reserved tones and free tones are not available, then the transmitter may use an alternative method to reduce distortion, such as successive clipping and filtering. In another embodiment, the transmitter may transmit PAPR-reduction symbols over both free and reserved tones, if available.

Techniques are disclosed for compensating for second-order distortion in a wireless communication device. In a zero-intermediate frequency (IF) or low-IF architecture, IM2 distortion generated by the mixer (20) results in undesirable distortion levels in the baseband output signal. A compensation circuit (104) provides a measure of the IM2 distortion current independent of the radio frequency (RF) pathway to generate an IM2 calibration current. The IM2 calibration current is combined with the baseband output signal to thereby eliminate the IM2 currents generated within the RF pathway. In one embodiment, the calibration is provided at the factory during final testing. In alternative embodiment, additional circuitry (156, 158) may be added to the wireless communication device to provide a pathway between the transmitter (150) and the receiver (146). The transmitter signal is provided to the receiver to permit automatic calibration of the unit. An internal signal source (162) may be used in place of the transmitter (150). The auto-calibration may be performed to eliminate IM2 distortion or permit optimization of the circuit to minimize other forms of distortion or interference.

Included are embodiments for image distortion reduction in web printing. Some embodiments are configured for determining an ink drop speed of ink from a printer and determining a web travel speed of a web of material, where the web of material engages with a folding board during printing that manipulates a plane of the web of material such that a projection of the web width is effectively reduced. Some embodiments may be configured for determining an altered web geometry of the web of material while engaging with the folding board, receiving a desired image for printing on the web of material, and calculating a pixel displacement of the plurality of pixels. Some embodiments may be configured for creating an altered image that utilizes the pixel displacement from the desired image and sending data related to the altered image for printing on the web of material.

A method is disclosed for transforming a wide-angle video image in to a Perspective view or a Cylindrical video image with reduced distortion. The method for providing an output image in either a Cylindrical mode or a Perspective mode, and comprising steps of: (1) acquiring a wide-angle image, which is a circular projection image, which format selected from the group of full circle, rounded rectangle, and full projection; (2) using a degree of view (DOV) and a radius of a projected circular region of the wide-angle image to select an image in one of Azimuthal modes; (3) specifying a horizontal field of view range (HFOVR) and a vertical field of view range (VFOVR) as a source projection image region, which is in Azimuthal mode; (4) converting the source projection image region in Azimuthal mode into a new source projection image region in Cylindrical mode; (5) converting the new source projection image in Cylindrical mode into another source projection image in Perspective mode; and (6) generating the output image.

Volume extension includes limiting the magnitude of Fast Fourier Transform (FFT) frequency bins which allows increases to the perceived level of audio content without causing distortion. A soft limit and smoothing is applied to each FFT bin is to prevent or reduce distortion while maximizing output volume. Frequency resolution is significantly improved compared to volume extension methods utilizing filterbanks and hard limiting, and distortion is reduced because no hard limiting occurs.

A method for adaptive digital post distortion reduction is described. An analog radio frequency (RF) signal is received. The frequency of the analog RF signal is downconverted using analog circuitry. The analog RF signal is converted to a digital signal using an analog to digital converter (ADC). Digital post distortion reduction is applied to the digital signal to reduce nonlinearities in the digital signal.

Techniques are disclosed for compensating for second-order distortion in a wireless communication device. In a zero-intermediate frequency (IF) or low-IF architecture, IM2 distortion generated by the mixer (20) results in undesirable distortion levels in the baseband output signal. A compensation circuit (104) provides a measure of the IM2 distortion current independent of the radio frequency (RF) pathway to generate an IM2 calibration current. The IM2 calibration current is combined with the baseband output signal to thereby eliminate the IM2 currents generated within the RF pathway. In one embodiment, the calibration is provided at the factory during final testing. In alternative embodiment, additional circuitry (156, 158) may be added to the wireless communication device to provide a pathway between the transmitter (150) and the receiver (146). The transmitter signal is provided to the receiver to permit automatic calibration of the unit. An internal signal source (162) may be used in place of the transmitter (150). The auto-calibration may be performed to eliminate IM2 distortion or permit optimization of the circuit to minimize other forms of distortion or interference.

System and method for integrating an input signal to generate an output signal. The system includes a first integrator configured to receive the input signal and generate an integrated signal based on at least information associated with the input signal, a second integrator configured to receive the integrated signal and generate the output signal based on at least information associated with the integrated signal, and a compensation capacitor coupled to the first integrator and the second integrator. The first integrator includes a first integration capacitor and a first operational amplifier including a first input terminal and a first output terminal, the first integration capacitor being coupled between the first input terminal and the first output terminal. The second integrator includes a second integration capacitor and a second operational amplifier including a second input terminal and a second output terminal.

An image processing apparatus capable of performing processing for reducing a shake in the image including a distortion without performing processing for reducing the distortion is disclosed. The apparatus includes a shake detecting part that detects a shake in a first image area of an input image including a distortion, a shake information generating part that generates shake information on a shake in a second image area of the input image based on the shake detected by the shake detecting part, and a shake reduction processing part that performs image processing for reducing the shake in the second image area based on the shake information without performing image processing for reducing the distortion on the input image.

The present invention is a digital to analog converter circuit that provides significantly lower distortion than achieved by digital to analog converter circuits having comparable speed and resolution utilizing the present art. The present invention provides linear or higher order transitions between clock transition time points rather than step transitions used in the present art. Distortion reduction can exceed 30 dB in the embodiment with linear sample-to-sample transitions and greater in alternate embodiments with non-linear transitions. In other embodiments, the present invention can provide low distortion at resolutions from 16 to 24 bits or more at sample rates typical of high-speed 8-bit devices of the present art.

A method and system for providing a mixed-mode (current- and voltage-source) audio amplifier is disclosed. The mixed-mode amplifier includes a voltage sensing feedback path including a first network comprising at least one circuit; and a current sensing feedback path including a second network comprising at least one circuit. According to the method and system disclosed herein, the first and second networks vary an output impedance or transconductance of the amplifier as a function of frequency of the input voltage signal, such that at a first frequency range, the amplifier operates substantially as a current amplifier, and at a second frequency range, the amplifier operates substantially as a voltage amplifier, thereby inheriting distortion reduction of the current amplifier and stability of the voltage amplifier.

Methods and systems are provided for receiving by a first electronic device audio content, determining audio quality of the received audio content, which includes measuring and / or estimating quality related parameters associated with the received audio content, and communicating the quality related parameters to a second electronic device, from which the audio content was transmitted. The quality related parameters may be used to control audio related functions in the second electronic device. The audio related functions may comprise noise reduction, noise suppression, cancellation, distortion reduction, equalization, compression, enhancement and / or audio rate conversion. Determining the audio quality of the received audio content may be based on one or more noise related thresholds. The quality related parameters may be communicated to the second electronic device over a dedicated control channel setup between the devices.

Disclosed is a distortion compensation circuit that reduces the time for convergence of distortion compensation data, without impairing any stability of distortion compensation. The circuit includes an error computation and compensation data updating section that repeats a computation in which errors between an input orthogonal baseband transmission signal and a feedback signal obtained by demodulating part of the output from a power amplifier are computed to obtain error data and values obtained by multiplying this error data by step coefficients are added to distortion compensation data before updating, thereby computing distortion compensation data after updating. Distortion compensation data for compensation of nonlinear distortion is thus updated. Step coefficients are stored in a step coefficient data memory with respect to each of different input signal amplitude values. Step coefficients corresponding to an input signal amplitude value computed by an amplitude computation section are output from the memory to multipliers.

The present invention reduces distortion in variable capacitance devices by connecting a circuit to the variable capacitance devices that has low impedance at predetermined frequencies to suppress those frequencies and also suppress harmonics and mixing products resulting from mixing of various frequencies.

System and method for integrating an input signal to generate an output signal. The system includes a first integrator configured to receive the input signal and generate an integrated signal based on at least information associated with the input signal, a second integrator configured to receive the integrated signal and generate the output signal based on at least information associated with the integrated signal, and a compensation capacitor coupled to the first integrator and the second integrator. The first integrator includes a first integration capacitor and a first operational amplifier including a first input terminal and a first output terminal, the first integration capacitor being coupled between the first input terminal and the first output terminal. The second integrator includes a second integration capacitor and a second operational amplifier including a second input terminal and a second output terminal.

An image processing apparatus performs distortion aberration correction appropriate for each of the cases where the image processing apparatus clips image data by performing electronic image stabilization and does not clip the image data by performing the electronic image stabilization. The image processing apparatus includes a correction unit configured to perform the distortion aberration correction on image data in which distortion aberration has, and a stabilization unit configured to perform clipping from the image data based on a movement of an imaging unit when the image data has been generated. The correction unit reduces an amount of the distortion aberration correction in a case where the stabilization unit does not clip the image data, as compared to a case where the stabilization unit clips the image data.

A method of signal processing includes receiving a distorted signal comprising a distorted component and an undistorted component, the distorted component being at least in part attributed to an exogenous signal, and performing linearization, based at least in part on the distorted signal and information associated with the exogenous signal, to obtain a corrected signal that is substantially similar to the undistorted component. An adaptive distortion reduction system includes an input interface configured to receive a distorted signal comprising a distorted component and an undistorted component, the distorted component being at least in part attributed to an exogenous signal; and an adaptive distortion reduction module coupled to the input interface, configured to perform linearization based at least in part on the distorted signal and information associated with the exogenous signal, to obtain a corrected signal that is substantially similar to the undistorted component.