942 results about "Low distortion" patented technology

The method and apparatus for information conveyance and distribution to bidirectionally focus or guide a wide spectrum of electromagnetic waves propagated over a possible variety of propagation media, including free space or wireless, surface wave, and cable or wired transmission lines. The apparatus communicates with information devices immediately adjacent to these media wherein the devices, which are not themselves part of the apparatus, may have electromagnetic access to one another. The apparatus maintains adequate signal to noise ratio and low distortion for a possible variety of different signal modulation and encoding types which it can support while permitting transparent, simultaneous communications among a variety of devices. Spread spectrum techniques may be used within the apparatus to mitigate propagation medium distortions and impairments as well as to control access and provide a means for securing information within the corridor and for obtaining revenue. Adapters may be employed to provide either full or half duplex access to the information devices which utilize it.

From a mixed signal in which a first signal and a second signal are mixed, the second signal is removed at low processing cost and without delay. As a result, an estimated first signal which has low residue of the second signal and low distortion is obtained.

An estimated first signal is generated by subtracting a pseudo second signal which is estimated to be mixed in a first mixed signal in which a first signal and a second signal are mixed from the first mixed signal. The pseudo second signal is obtained by a first adaptive filter using a second mixed signal in which the first signal and the second signal are mixed in a different proportion from the first mixed signal. A coefficient update amount of the first adaptive filter is made smaller as compared with a case when the estimated first signal is smaller than the first mixed signal, in case the estimated first signal is larger than the first mixed signal.

A method of making a low distortion frame construction, the construction having joint regions formed by first and second overlapping members defining a lapped interface, the joint regions being comprised of material that can be converted to a solid state deformable plastic condition by friction heat, comprising: (a) providing a stir friction welding tool having (i) a rotatable thermally conductive body presenting a shoulder to engage the joint region for storing friction-generated heat, and (ii) a friction generating pin rotatable with said body about a pin axis and selectively extendable from the shoulder to progressively penetrate the overlapping members as the joint region in contact with the pin becomes plastic; (b) placing the tool shoulder against the joint region with the pin axis transverse to the lapped interface and spinning the body while progressively extending the pin at a rotational speed effective to generate friction heat that converts the adjacent material of the joint to a plastic condition allowing the spinning of the probe to stir such plastically converted material; and (c) controlling the depth of penetration of the spinning probe while translating the tool across the joint region to perfect a friction stirred welded zone that extends through the interface and between the overlapping members to provide a welded joint that is exceptionally strong in shear.

Extended area lighting devices include a light guide and diffractive surface features on a major surface of the light guide, at least some diffractive surface features adapted to couple guided-mode light out of the light guide. The diffractive features include first and second diffractive features disposed on respective first and second portions of the major surface. A patterned light transmissive layer, including a second light transmissive medium, optically contacts the second diffractive features but not the first diffractive features. A first light transmissive medium optically contacts the first but not the second diffractive features. The first and second portions may define indicia, and the first and second diffractive features provide low distortion for viewing objects through the light guide such that the indicia is not readily apparent to users when guided-mode light does not propagate within the light guide. Optical films having such diffractive features are also disclosed.

There are provided a small optical deflector that can be driven at a high speed with a low voltage, provides a large angle of deflection, has a low distortion even in high speed operation and has a high static flatness of a reflective surface, and a method of producing the optical deflector. The optical deflector drives a movable plate relative to a supporting substrate to deflect a light incident on a reflective surface and has a configuration in which at least two recesses are formed in a surface of the movable plate on which the reflective surface is not formed, and a magnetic material is provided in the recesses.

System for pulse-width-modulated class D audio amplifiers. In one preferred embodiment an adder is described to generate a difference signal responsive to an input signal and a feedback signal, a pulse-width-modulator coupled to the adder to compare the difference signal to a reference signal and produce a pulse-width-modulated signal based on the comparing, a filter coupled to an output of the pulse-width-modulator, and a loop filter having a first input coupled to the output of the filter and a second input coupled to the input of the filter, the loop filter to generate a feedback signal by applying transfer functions to signals at its inputs. The loop transfer function of the amplifier is minimum aliasing error transfer function. The minimum aliasing error properties provide low distortion and taking the feedback from the output of the filter reduces high frequency output impedance.

There is a need for providing a projection optical system that is appropriate for maintaining high resolution with low distortion, miniaturizing a reflector, decreasing the number of reflectors, and decreasing the depth and the bottom (or top) of a display used for a rear projection television, for example. The projection optical system according to the invention enlarges and projects images from a primary image surface existing at a reducing side to a secondary image surface existing at an enlarging side. The projection optical system has a first optical system L11 and a second optical system L12. The first optical system L11 forms an intermediate image (position II) of the primary image surface. The second optical system L12 has a concave reflector AM1 that forms the secondary image surface resulting from the intermediate image. A light beam travels from the center of the primary image surface and to the center of the secondary image surface and crosses an optical axis. The light beam is reflected on the concave reflector, crosses the optical axis again, and reaches the secondary image surface.

An improved mathematically modeled family of bellow fold patterns, useful for making bellows from stiff but foldable materials, which forms a corner of a bellow consisting of a series of several single inversion fold patterns, each having a characteristic design angle which is mathematically computed to provide a desired initial wall angle for the bellow and to minimize wall tilting over a predetermined extension angle range, thereby allowing low cost bellows to be made which can extend long distances while using a minimal amount of stiff but foldable material. In addition, each characteristic design angle can be computed to provide exactly zero tilting of the bellow walls at one or more non-zero extension lengths specified by a designer, thus allowing, unlike all other prior art folds, a structurally stiff, long extending bellow to be formed in an extended state using fast production techniques such as vacuum forming, blow molding or injection molding, while also allowing the bellow to be free of distortion in the compressed state.

This invention relates to a method and system of transmitting video data and data to a plurality of client radio receivers over an air interface using an adaptive encoding/transcoding scheme and updating the adaptive encoding/transcoding scheme in dependence upon received feedback data. The invention further describes estimating channel states and distortion levels for a plurality of transmission modes, then selecting that transmission mode for subsequent data transmission that has the lowest distortion level. Control data items can be extracted from the first data stream to produce a multimedia data stream and a control data stream and the multimedia data stream is transmitted over a first channel; the control data stream is transmitted over a second channel. The received data stream may be put into a plurality of multimedia slices having a predetermined slice size; and encoded into first data packets of a first predetermined size; which are divided into respective integral second data packets of a second predetermined size and are aggregated into a stream of third data packets of a third predetermined size.

A receiver for a resonance signal of a magnetic resonance imaging system generates a baseband signal for image processing by dividing a raw resonance signal among multiple parallel channels, each amplified at a respective gain. A digital channel selector determines, at any given moment, a lowest-distortion channel to be further processed. Amplitude and phase error compensation are handled digitally using complex multipliers, which are derived by a calibration, based on a simple Larmor oscillator, which can be done without the need for a sample and without repeating when measurement conditions are changed. One of the important benefits of the invention is that it provides for gain selection without repeated calibration steps. This is particularly important in systems that employ fast imaging techniques such as fast spin echo, where the invention can speed imaging substantially.

A method (and system) for generating an output file from a source file where benign modifications to a content of the output file still render the output file authentic, includes constructing an index vector from the source file, quantizing the source file, generating an authentication mark from the quantized source file and the index vector, generating an authentication tag by appending the index vector to the authentication mark, and generating the output file by appending the authentication tag to the source file.

Hyper-hemispherical images may be combined to generate a rectangular projection of a spherical image having an equatorial stitch line along of a line of lowest distortion in the two images. First and second circular images are received representing respective hyper-hemispherical fields of view. A video processing device may project each circular image to a respective rectangular image by mapping an outer edge of the circular image to a first edge of the rectangular image and mapping a center point of the circular image to a second edge of the first rectangular image. The rectangular images may be stitched together along the edges corresponding to the outer edge of the original circular image.

Systems and methods for providing imaging content using spatially varying encoding quality. Imaging content may be acquired using spherical lenses (e.g., fisheye). When viewing spherical imaging content, spherical to planar image transformations may be utilized. Such transformations (e.g., equirectangular) may be characterized by spatially varying image distortion. Transformed images may be encoded. Encoding process may be configured based on spatially varying encoding quality. Encoding quality may be configured based on the transformation such that portions of the transformed image characterized by greater distortion may be encoded using lower quality (e.g. greater QP values); portions of the transformed image characterized by lower distortion may be encoded using greater quality (e.g. lower QP values). Such encoding may produce a bitstream characterized by a lower bitrate for a given quality and/or better quality for a given bitrate as compared to an encoding process that may apply a uniform encoding quality.

A low distortion, high frequency switch circuit for selectively coupling an input voltage terminal to an output voltage terminal includes a switching device coupled to the input voltage terminal and the output voltage terminal, a charge storage device, and a first, second and third switches. While the switch circuit is turned off, the charge storage device, typically a capacitor, is charged to a precharge voltage. Then, when the switch circuit is to be turned on, the charge storage device is coupled between the control terminal of the switching device and the input voltage terminal. As a result, the switching device receives a constant gate-to-source voltage approximately equals to the precharge voltage and becomes conductive with a minimum and constant R_ON for all values of input voltages. In another embodiment, the switch circuit includes a pedestal voltage compensation circuit for reducing charge injection induced pedestal errors.

A low-distortion band-pass delta-sigma analog-to-digital converter (ADC), including an odd-phase sample and hold circuit coupled to a even-phase resonator, improves tolerance to mismatches between analog circuit components. The low-distortion ADC includes a feed-forward signal path that reduces, or eliminates, the input signal beyond the first summation point. In this way, the dynamic range and matching accuracy required of the resonator is reduced. An odd-phase sample and hold circuit shifts S/H spurious signals out-of-band. A two-phase resonator reduces in-band noise degradation caused by any mismatches between the resonator components.

The invention relates to a method for manufacturing a sectional and segmented gold fingerplate by a selective wet membrane method, comprising the following: a step of resistance welding, in which the gold fingerplate is subjected to resistance welding; a step of selecting a wet membrane, in which the wet membrane is selected to protect the sectional and segmented position of the gold fingerplate; a step of microetching, in which the copper surface of the gold fingerplate is microetched; a step of plating a gold finger, in which the gold fingers except the sectional and segmented position is gilded; a step of removing the selective wet membrane; and a step of etching for the second time, in which an attach tape is adopted to protect the copper surface of the gold fingerplate, and the sectional and segmented positions of the gold finger are etched. The method manufactures the sectional and segmented gold fingerplate by the selective wet membrane method, is used for removing plating lead wires, has easily controlled production process, and has low distortion rate of the signal and high accuracy when a client uses the method on a core network.

Systems and methods for performance improvements in digital switching amplifiers using low-pass filtering to reduce noise and distortion. In one embodiment, a digital pulse width modulation (PWM) amplifier includes a signal processing plant configured to receive and process an input audio signal. The amplifier also includes a low-pass filter configured to filter audio signals output by the plant. The filtered output of the plant is added to the input audio signal as feedback. The plant may consist of a modulator and power switch, a noise shaper, or any other type of plant. An analog-to-digital converter (ADC) may be provided to convert the output audio signal to a digital signal. Filtering may be implemented before or after the ADC, and a decimator may be placed after the ADC if it is an oversampling ADC.

A regulated power supply having power factor correction control includes a multi-vector error amplifier. The multi-vector error amplifier provides an error signal that is used to regulate a switching mechanism of the power supply. The multi-vector error amplifier acts to provide a low distortion error signal during steady-state operation, while responding rapidly and smoothly to sudden load changes.

A combined signal of a digital pilot signal and a digital transmission signal is applied to a digital predistorter (20), wherein it is added with odd-order distortions based on a power series model to generate a predistorted signal, then the predistorted signal is converted by a DA converter (31) to an analog signal, then the analog signal is upconverted by a frequency upconverting part (33) to a send frequency band, and the upconverted signal is output after being amplified by a power amplifier (37). A pilot signal component is extracted from the power amplifier output, then odd-order distortion components of the power series model are extracted by a digital predistorter control part (50) from the pilot signal component, and the odd-order distortions in the digital predistorter (20) are controlled to decrease the levels of the distortion components.

Polypropylene resin expanded particles include polypropylene resin as base material resin having at least two melting peaks on a DSC curve, the at least two melting peaks including (i) a lowest-temperature melting peak of 100° C. or more but 130° C. or less and (ii) a highest-temperature melting peak of 140° C. or more but 160° C. or less, so that the expanded particles: produce an in-mold foaming molded product at a very low mold heating steam pressure; exhibit low distortion, low shrinkage, and a wide range of heating condition for molding, even if the mold heating steam pressure is increased; have satisfactory moldability when the expanded particles are molded by using a mold having a complicated shape or a large mold; and maintain properties such as compressive strength, substantially unimpaired, when the expanded particles make the in-mold foaming molded product.

The invention discloses a digital electric energy meter checking device based on an analog source tracing method, which is used for the accuracy testing of an electric energy meter based on an IEC61850 standard. The device comprises an AC signal conditioning board, a central control board, an industrial personal computer and a liner power panel which provides power to the device, wherein the AC signal conditioning board carries out front-end low-distortion conversion to three-phase voltage and three-phase current provided by a circumscribed standard power source, and the three-phase voltage and the three-phase current are converted into a voltage signal ranged by the AD analog to digital converter of the rear central control board; the central control board finishes the functions of AC signal sampling, electricity energy accumulation, IEC61850 standard communication, error calculation and data exchange with the industrial personal computer; the industrial personal computer is used for developing a human-computer interface, finishing the functions of giving an order, communicating data and displaying a result and exchanging the order and the data with the central control board via a serial port. The self precision of the checking device reaches 0.05 level, and the magnitude can be upwards traced to the source to higher level of the existing national standard.