114 results about "Instantaneous bandwidth" patented technology

Reconfiguration of parasitically controlled elements in a phased array is used to expand the range of operational functions. Embedded array elements can be frequency tuned, and bandwidth can be improved by using reconfiguration to broaden the bandwidth of the embedded elements. For high gain arrays, beam squint can be a limiting factor on instantaneous bandwidth. Reconfiguration can alleviate this problem by providing control of the element phase centers. Scan coverage can be improved and scan blindness alleviated by controlling the embedded antenna patterns of the elements as well as by providing control of the active impedance as the beam is scanned. Applying limited phase control to the elements themselves can alleviate some of the complexity of the feed manifold. A presently preferred method of designing reconfigurable antennas is to selectively place controlled parasitic elements in the aperture of each of the antenna elements in the phased array. The parasitic elements can be controlled to change the operational characteristics of the antenna element. The parasitic elements are controlled by either switching load values in and out that are connected to the parasitic elements or are controlled by applying control voltages to variable reactance circuits containing devices such as varactors. The parasitic elements can be controlled by the use of a feedback control subsystem that is part of the antenna system which adjusts the RF properties of the parasitic components based on some observed metric. The controllable characteristics include directivity control, tuning, instantaneous bandwidth, and RCS.

The present invention provides an advanced adaptive predistortion linearization technique to dramatically reduce nonlinear distortion in power amplifiers over a very wide instantaneous bandwidth (up to 2 GHz) and over a wide range of amplifier types, input frequencies, signal types, amplitudes, temperature, and other environmental and signal conditions. In an embodiment of the invention, the predistortion linearization circuitry comprises (1) a higher-order polynomial model of an amplifier's gain and phase characteristics—higher than a third-order polynomial model; (2) an adaptive calibration technique; and (3) a heuristic calibration technique. The higher-order polynomial model is generated by introducing, for example, a plurality of multi-tone test signals with varying center frequency and spacing into the power amplifier. From the power amplifier's corresponding output, the nonlinearities are modeled by employing a higher-order curve fit to capture the irregularities in the nonlinear transfer function. Different distortion transfer functions can be implemented for different operating conditions. The adaptive calibration technique is based on a feedback analysis technique, which updates the applicable distortion transfer function by analyzing the error signal between the introduced input signal and the output signal in real-time. The heuristic calibration technique implements different distortion transfer functions based on historical operating conditions and optimal configurations of the power amplifier.

What is provided is a receiver-on-a-chip comprising a monolithic integrated circuit that reduces the receiver to a cigarette-pack-sized assembly mountable directly at an antenna element, with a much-increased operational bandwidth and instantaneous bandwidth, increased dynamic range and with a two-order-of-magnitude decrease in size and weight. Moreover, because of the elimination of all of the I / O drivers and attendant circuitry, power consumption is reduced by two-thirds, whereas the mean time before failure is increased to 10,000 hours due to the robustness of the monolithic integrated circuit and use of fiber optics.

Reconfiguration of parasitically controlled elements in a phased array is used to expand the range of operational functions. Embedded array elements can be frequency tuned, and bandwidth can be improved by using reconfiguration to broaden the bandwidth of the embedded elements. For high gain arrays, beam squint can be a limiting factor on instantaneous bandwidth. Reconfiguration can alleviate this problem by providing control of the element phase centers. Scan coverage can be improved and scan blindness alleviated by controlling the embedded antenna patterns of the elements as well as by providing control of the active impedance as the beam is scanned. Applying limited phase control to the elements themselves can alleviate some of the complexity of the feed manifold. A presently preferred method of designing reconfigurable antennas is to selectively place controlled parasitic elements in the aperture of each of the antenna elements in the phased array. The parasitic elements can be controlled to change the operational characteristics of the antenna element. The parasitic elements are controlled by either switching load values in and out that are connected to the parasitic elements or are controlled by applying control voltages to variable reactance circuits containing devices such as varactors. The parasitic elements can be controlled by the use of a feedback control subsystem that is part of the antenna system which adjusts the RF properties of the parasitic components based on some observed metric. The controllable characteristics include directivity control, tuning, instantaneous bandwidth, and RCS.

The invention relates to a broadband linear frequency-modulated (LFM) signal multi-decoy interference method based on fractional Fourier domain channelization, in particular to an interference method for performing multi-decoy deception on a broadband LFM signal in a pulse on the basis of fractional Fourier domain channelization, and belongs to the technical field of electronic interference. According to the broadband LFM signal multi-decoy interference method based on fractional Fourier domain channelization, all broadband LFM signals can be focused into one channel for outputting by using the energy focusing property of fractional Fourier transform on instable signals, so that the completeness of the signals is ensured, and the problems of reduction of signal energy and distortion of waveforms since the energy of the broadband LFM signals overflow into two or more channels in the conventional Fourier domain channelization are solved; meanwhile, the requirement on the instant bandwidth of a DRFM (Digital Radio Frequency Memory) system is lowered.

The present invention provides an advanced adaptive predistortion linearization technique to dramatically reduce nonlinear distortion in power amplifiers over a very wide instantaneous bandwidth (up to 2 GHz) and over a wide range of amplifier types, input frequencies, signal types, amplitudes, temperature, and other environmental and signal conditions. In an embodiment of the invention, the predistortion linearization circuitry comprises (1) a higher-order polynomial model of an amplifier's gain and phase characteristics—higher than a third-order polynomial model; (2) an adaptive calibration technique; and (3) a heuristic calibration technique. The higher-order polynomial model is generated by introducing, for example, a plurality of multi-tone test signals with varying center frequency and spacing into the power amplifier. From the power amplifier's corresponding output, the nonlinearities are modeled by employing a higher-order curve fit to capture the irregularities in the nonlinear transfer function. Different distortion transfer functions can be implemented for different operating conditions. The adaptive calibration technique is based on a feedback analysis technique, which updates the applicable distortion transfer function by analyzing the error signal between the introduced input signal and the output signal in real-time. The heuristic calibration technique implements different distortion transfer functions based on historical operating conditions and optimal configurations of the power amplifier.

A reconfigurable antenna array capable of utilizing a common antenna aperture which can cover a wide frequency range in a continuous way. With the basic antenna element based on a slot-ring and using a self similar structure approach and RE' switches, the antenna array operates without grating lobes. The antenna array exhibits polarization diversity and single-side radiation capability. When varactors are implemented into the array, the antenna array can cover the frequency range by continuously tuning the center frequency with a relatively narrow instantaneous bandwidth.

A method for predicting pore pressure is described which initially involves obtaining, for one point in a volume of Earth, a value of pore pressure and one or more seismic attributes. A relationship is determined between the value of pore pressure and the seismic attribute, for example by use of a neural network. Seismic data is then obtained for the volume of earth and the same attributes as selected above when determining relationship are extracted from the seismic data for another point in the volume. The extracted seismic attributes are then used as inputs to the previously determined relationship to produce as an output, a prediction of pore pressure at the other point. The seismic attributes are frequency related seismic attributes and include for example instantaneous frequency, weighted mean frequency, instantaneous pseudo-quality factor, instantaneous dominant frequency, instantaneous bandwidth, instantaneous phase, effective bandwidth, peak frequency, envelope and energy half time.

Some embodiments provide a method for estimating bandwidth estimate based on a set of statistical measurements that quantifies bandwidth variation. The method receives a piece of media content at a receiving device and computes several instantaneous bandwidth measurements based on sample data blocks or media content received at the receiving device. The method computes the set of statistical measures that quantifies variation between the computed instantaneous bandwidth measurements. Based on the set of statistical measures, the method computes a revised bandwidth estimate for receiving media content at the receiving device. In some embodiments, the method uses the revised bandwidth estimate to determine an amount of media content data to buffer in order to provide an uninterrupted playback.

The present invention provides a high-performance adaptive digital receiver with adaptive background control that optimizes the performance in rapidly changing signal environments and provides 3.6 GH; instantaneous bandwidth, SFDR>90 dB, SNR=66 dB, with dynamic digital channelization. The receiver takes advantage of several levels of adaptivity that conventional approaches do not offer. In addition to a dynamic digital channelizer that is adaptively tuned based on detected signals, the present invention employs a powerful software reconfigurable digitizer that is adaptively optimized for the current signal environment to control important receiver parameters such as bandwidth, dynamic range, resolution, and sensitivity.

A system including a power amplifier and a pre-distortion module coupled to the power amplifier. The pre-distortion module includes one or more smaller versions of the power amplifier to generate a pre-distortion signal that compensates for any memory-effect or inertia present in the power amplifier with application on frequency hopping and larger (up to 1 octave) instantaneous bandwidth communication systems.

A method and system use the mutual coupling property of multiple antenna elements for measuring differences in propagation time among various signal paths involving antenna elements in a radio frequency transmit / receive system. The method and system alleviate the need for external test equipment by using the same hardware used in standard operation of the transmit / receive system for performing propagation time measurement through the generation, mutual coupling, and acquisition of a specially selected reference signal. In an embodiment involving calibration of various signal paths to realize matched propagation times, the signal energy returned through these various paths during standard system operation arrives for acquisition more closely coincident in time, increasing the instantaneous bandwidth of the system.

A method to minimize influence of interference sources by control of a signal to noise / interference ratio of a wideband antenna system connected to an electronic system. The wideband antenna system includes at least one array of at least two antenna elements / sub arrays. The signal to noise / interference ratio control includes establishing of cancellation directions for interfering frequencies in the antenna pattern in the direction of interference sources. The wideband antenna system is operational over a system bandwidth and operates with an instantaneous bandwidth. Estimation of interference source parameters is performed in an evaluation process. A wideband antenna system implementing the method.

A system determines bandwidth use by queues in a network device. To do this, the system determines an instantaneous amount of bandwidth used by each of the queues and an average amount of bandwidth used by each of the queues. The system then identifies bandwidth use by each of the queues based on the instantaneous bandwidth used and the average bandwidth used by each of the queues.

A method and apparatus are provided for managing varying traffic loads in a packetized communication network. At a predefined location, the instantaneous demand for bandwidth required for delivering traffic via a plurality of active channels is compared with the available bandwidth. When the available bandwidth at that pre-defined location is less than the bandwidth required to convey the signals carried along all these active channels, a rate adjusting mechanism is applied to at least one of the active channels, while repeating this check periodically. The rate adjusting mechanism is applied on packetized signals arriving along at least one group of active channels so as to ensure that: a substantially equalized signal quality is maintained for signals delivered via all of the active channels belonging to certain one or more groups of active channels, and the instantaneous overall bandwidth required to convey all the signals arriving at the pre-defined location, is not more than the available instantaneous bandwidth.