1195 results about "Wideband signal" patented technology

A waveform adaptive transmitter that conditions and/or modulates the phase, frequency, bandwidth, amplitude and/or attenuation of ultra-wideband (UWB) pulses. The transmitter confines or band-limits UWB signals within spectral limits for use in communication, positioning, and/or radar applications. One embodiment comprises a low-level UWB source (e.g., an impulse generator or time-gated oscillator (fixed or voltage-controlled)), a waveform adapter (e.g., digital or analog filter, pulse shaper, and/or voltage variable attenuator), a power amplifier, and an antenna to radiate a band-limited and/or modulated UWB or wideband signals. In a special case where the oscillator has zero frequency and outputs a DC bias, a low-level impulse generator impulse-excites a bandpass filter to produce an UWB signal having an adjustable center frequency and desired bandwidth based on a characteristic of the filter. In another embodiment, a low-level impulse signal is approximated by a time-gated continuous-wave oscillator to produce an extremely wide bandwidth pulse with deterministic center frequency and bandwidth characteristics. The UWB signal may be modulated to carry multi-megabit per second digital data, or may be used in object detection or for ranging applications. Activation of the power amplifier may be time-gated in cadence with the UWB source thereby to reduce inter-pulse power consumption. The UWB transmitter is capable of extremely high pulse repetition frequencies (PRFs) and data rates in the hundreds of megabits per second or more, frequency agility on a pulse-to-pulse basis allowing frequency hopping if desired, and extensibility from below HF to millimeter wave frequencies.

A method and apparatus are disclosed for a wireless communication device to simultaneously receive at least two signals. Two receiver portions are provided in the wireless communication device. A first receiver portion is configured to receive a first communication signal. A second receiver portion is configured to receive a second communication signal. The two receiver portions are configured to convert the first and second communication signals to a common frequency band. The common frequency band may be an intermediate frequency band or baseband frequency band. The converted first and second communication signals are combined in the common frequency band using an adder or other signal combiner. The combined signal is processed in a single signal processor. The communication device is able to resolve each of the received signals when the first communication signal is a narrowband signal and the second communication signal is a wideband signal, such as a spread spectrum signal.

An intelligent gain controller operates to control the gain in each one of wideband uplink and downlink signal paths. Weak desired signals, within each wideband signal path, are detected using a narrowband down converter and detector, and these desired signals monitored by the micro controller. Based on the monitored signals, the micro controller operates, under control of suitable software implementing an Adaptive Control Algorithm, to adjust the gain in each of the uplink and downlink paths in order to dynamically optimize performance.

A wideband signal generator according to one embodiment of the invention includes a variable frequency source and a direct digital synthesizer. Local oscillators, signal analyzers, modulators, demodulators, and other equipment including one or more such generators are also disclosed.

There is disclosed an encoding device capable of improving similarity between the high frequency band spectrum of the original signal and a new spectrum to be generated while realizing a low bit rate when encoding a wide-band signal spectrum. The encoding device has sub-band amplitude calculation units (122, 128) for calculating the amplitude of the respective sub-bands for the high frequency band spectrum obtained from the wide-band signal. A search unit (124) and a gain codebook (125) select some sub-bands from a plurality of sub-bands and only the gain of the selected sub-bands is subjected to encoding. An interpolation unit (126) expresses the gain of the sub-band not selected, by mutually interpolating the selected gains.

Systems, methods and apparatus for automatic signal detection with temporal feature extraction in an RF environment are disclosed. An apparatus learns the RF environment in a predetermined period based on statistical learning techniques, thereby creating learning data. A knowledge map is formed based on the learning data. The apparatus automatically extracts temporal features of the RF environment from the knowledge map. A real-time spectral sweep is scrubbed against the knowledge map. The apparatus is operable to detect a signal in the RF environment, which has a low power level or is a narrowband signal buried in a wideband signal, and which cannot be identified otherwise.

The gain smoothing method and device modify the amplitude of an innovative codevector in relation to background noise present in a previously sampled wideband signal. The gain smoothing device comprises a gain smoothing calculator for calculating a smoothing gain in response to a factor representative of voicing in the sampled wideband signal, a factor representative of the stability of a set of linear prediction filter coefficients, and an innovative codebook gain. The gain smoothing device also comprises an amplifier for amplifying the innovative codevector with the smoothing gain to thereby produce a gain-smoothed innovative codevector. The function of the gain-smoothing device improves the perceived synthesized signal when background noise is present in the sampled wideband signal.

The present invention provides an adaptive, intelligent transform based Analog to Information Converter (AIC) for wideband signals by directly converting an analog signal to information (e.g., features, decisions). This direct conversion is achieved by (i) capturing most of the information of a wideband signal via hardware/software implemented mathematical transformations, (ii) effectively removing unwanted signals such as jammer and interfere from the input signal, and (iii) using novel algorithms for highly accurate decision making and feature extraction (e.g., high probability of detection with low probability of false alarm). The jump in the improvement over today's state-of-the-art is in terms of effective and optimum signal information extraction at high-speed.

A communication system is provided which allows video and audio/video transmissions over unloaded, twisted pairs of telephone wires. The system provides for automatic compensation of attenuation of a broadband video signal by measuring the attenuation of the low frequency components of the signal to determine the length of the unloaded, twisted pair through which the signal has been transmitted. This calculation is performed by comparing the attunated signal with the known signal level of transmission. Based upon the calculated length, the signal is amplified nonlinearly, since a greater loss occurs in the high frequency portions of a broadband signal than in the low frequency portions in transmission over twisted pairs of telephone wires. The signal is thereupon reconstructed. Also, the system allows transmission of a broadband frequency spectrum much wider than has heretofore been obtained. A broadband signal of at least 10.7 MHz can be transmitted over the system. The system also provides for left and right audio inputs and outputs, as well as auxiliary inputs and outputs. The transmission system can be utilized so that persons with a video camera and a personal computer can communicate with each other, transmitting full-motion, color video over unloaded, twisted pairs of telephone wires.

The invention provides audio bandwidth expansion coding and decoding devices which can reconstruct a high frequency signal by using the lower code rate so as to improve the quality of the output audio signal. The audio bandwidth expansion coding device comprises a frequency division module, a core coder module, a linear prediction analysis module, a spectrum envelope quantization module, a high and low frequency correlation computation module and a gain computation module; and the audio bandwidth expansion decoding device comprises a core decoder module, a high-frequency spectrum envelope reconstruction module, a high-frequency residual error reconstruction module, a high-frequency gain adjustment module, a high-frequency signal synthesis module and a wideband signal reconstruction module.

The present invention relates to an ultra wideband internal antenna, which is provided in a mobile communication terminal to cut off frequencies in a certain frequency band while processing ultra wideband signals. The ultra wideband internal antenna includes a first radiation part, a second radiation part, a feeding part and a ground part. The first radiation part is made of a metal plate on a top surface of a dielectric substrate and is provided with at least one cut part, formed by cutting out a lower corner portion thereof, and an internal slot. The second radiation part is formed in the slot of the first radiation part while being connected to the first radiation part, the second radiation part being conductive. In this case, the first and second radiation parts form an ultra wide band due to electromagnetic coupling therebetween using individual currents flowing into the first and second radiation parts.

An integrated swept wavelength tunable optical source uses a narrowband filtered broadband signal with an optical amplifier and self-tracking filter. This source comprises a micro optical bench, a source for generating broadband light, a tunable Fabry Perot filter, installed on the bench, for spectrally filtering the broadband light from the broadband source to generate a narrowband tunable signal, an amplifier, installed on the bench, for amplifying the tunable signal. The self-tracking arrangement is used where a single tunable filter both generates the narrowband signal and spectrally filters the amplified signal. In some examples, two-stage amplification is provided. The use of a single bench implementation yields a low cost high performance system. For example, polarization control between components is no longer necessary.

Wideband signal generation systems and methods are provided which employ frequency interleaving for generating wideband signals. A general method increases a digitally synthesized signal's bandwidth by frequency interleaving multiple digitally synthesized signal sources of narrower bandwidth. Frequency interleaving creates a continuous wideband signal by summing multiple narrower band signals that overlap in frequency. According to certain embodiments, digital signal processing (DSP) and analog mixing are used to create the multiple narrower band signals such that a high fidelity, continuous wideband signal is produced when the multiple narrower band signals are summed.

A system and a method for medium wide band communications using impulse radio techniques. The method of transmitting medium wide band signals includes the steps of producing a sinusoidal signal and a train of preferably Gaussian shaped pulses. The method also includes the steps of multiplying the sinusoidal signal by the train of pulses to produce a train of sinusoidal bursts, and transmitting the train of sinusoidal bursts. The center frequency of the transmitted signal consisting of the train of sinusoidal bursts can be controlled by selecting an appropriate frequency of the sinusoidal signal. The bandwidth of the transmitted signal can be controlled by selecting an appropriate width of the pulses in the train of pulses. Information and/or coding modulation can be accomplished by adjusting the time position and/or phase of the sinusoidal bursts.

A frequency agile cable modem termination system which is configured to receive cable TV or other broadband signals on a frequency allocated basis. Cable TV headend may receive cable TV modem or other signals via optical/electrical converters and other links, and route those signals through a frequency multiplexer to divide individual feeds into separated frequency slots. The cable modem termination system may then have receivers tuned to individual slots allocated to data feeds, such as Internet, video, telephony or other sources, and route those sources over the Internet. Upon a failure condition within any given receiver or other component, a backup cable modem termination system, connected to the same common bus as the main or active system, may be rapidly activated by having backup receivers contained in that unit tuned to appropriate frequencies to pick up the signals within the corresponding band. Reliability and robustness is increased, and cabling requirements are decreased.

A method for reducing interference, comprising receiving a wideband signal, having at least one large amplitude component; adaptively modifying the wideband signal with respect to at least one high intensity component without substantial introduction of non-linear distortion, while reducing a residual dynamic range thereof; digitizing the modified wideband signal to capture information describing at least the high intensity signal at a sampling rate sufficient to extract modulated information present within the wideband signal at an upper limit of the band. The system analyzes a spectral characteristic of the wideband signal; and extracts adaptation parameters for the adaptive filtering. The system therefore provides both large net dynamic range and wideband operation. Preferably, the digitizer and filter, and part of the spectral characteristic analyzer is implemented in using superconducting circuit technology, with, for example low temperature superconducting digital signal processing components, and high temperature superconducting analog filtering components.