5189 results about "Narrowband" patented technology

An energy harvesting circuit includes one or more broadband or narrow band antennas to detect WIFI (wireless fidelity) or other RF (radio frequency) signals. The signals are rectified and voltage multiplied, and the resultant DC voltage is provided to a power management circuit. The output of the power management circuit charges a lithium battery or other storage device within the energy harvesting circuit. The energy stored in the battery or storage device is provided through a DC/DC converter circuit to a USB output connector to power or recharge the batteries of an external electronic device connected to the USB output connector of the energy harvesting circuit.

The invention includes a method, apparatus, and computer program to selectively suppress wind noise while preserving narrow-band signals in acoustic data. Sound from one or several microphones is digitized into binary data. A time-frequency transform is applied to the data to produce a series of spectra. The spectra are analyzed to detect the presence of wind noise and narrow band signals. Wind noise is selectively suppressed while preserving the narrow band signals. The narrow band signal is interpolated through the times and frequencies when it is masked by the wind noise. A time series is then synthesized from the signal spectral estimate that can be listened to. This invention overcomes prior art limitations that require more than one microphone and an independent measurement of wind speed. Its application results in good-quality speech from data severely degraded by wind noise.

A method and device which dynamically detects, tracks and filters interfering signals with sufficient speed (i.e. within one IS-95 CDMA data frame period, or 20ms and fidelity to eliminate or greatly reduce the deleterious effects of narrow band interferor signals on a CDMA link. When inserted in an RF signal path an Adaptive Notch Filter (ANF) detects narrow band interferors above a threshold level within the CDMA signal. Detection is accomplished by continuous scanning of a preset excision band, e.g. a specified narrow band associated with an AMPS system. Detected interferors are then automatically acquired and suppressed. This is achieved by electronically placing a rejection notch at the frequency of the interferors. Multiple notch filters may be used to simultaneously suppress multiple interferors. In the absence of interferors a bypass mode is selected allowing the RF signal to bypass the notch. Upon detection of an interferor, a switch is made to a suppression mode where the interferor is steered through a first notch section and suppressed. Alternatively, an external control line may be used to select the bypass mode so that the signal is allowed to pass the notch section, regardless of interferer content.

A resonant grating structure in a waveguide and methods of tuning the performance of the grating structure are described. An apparatus includes a waveguide; and a subwavelength resonant grating structure embedded in the waveguide. The systems and methods provide advantages including narrowband filtering capabilities, minimal sideband reflections, spatial control, high packing density, and tunability.

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.

Wireless communications for frequency-selective fading channels is realized by employing a system including orthogonal frequency division multiplexing (OFDM) in combination with an at least two antenna transmit diversity arrangement. Specifically, OFDM converts a multipath channel into a plurality of narrowband subchannels each having flat fading. Then, the signals on the same frequency subchannels of the at least two antennas are grouped together. Considering a first frequency subchannel, during a first OFDM time interval, a first signal and a second signal are transmitted on the first frequency subchannel from a first antenna (0) and from a second antenna (1), respectively. During a second OFDM time interval, a reverse sign (−) complex conjugate of the second signal and a complex conjugate of the first signal are transmitted from the first antenna and the second antenna, respectively. In a specific embodiment of the invention, reduced complexity in the implementation is realized by a reverse order complex conjugate and a reverse order, reverse sign (−) complex conjugate and judicious selection of the processed data signals in order to transmit the appropriate ones of the signals during the first and second OFDM intervals. Again, if the channel remains constant over the two OFDM intervals, diversity combination is realized for each frequency subchannel. In another embodiment of the invention, antenna-group hopping is employed in conjunction with pairing in time of the OFDM frequency subchannel signals to realize increased transmit diversity without rate loss.

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.

There is provided herein a system and method of seismic data collection for land and marine data that utilizes narrowband to monochromatic low-frequency non-impulsive sources designed to optimize the ability of migration/inversion algorithms to image the subsurface of the Earth, in particular, full-waveform inversion.

The present invention discloses a low-cost light source for optical transmission systems and optical networks based on wavelength-division multiplexing (WDM) technology. A light source in accordance with the present invention is implemented by externally injecting a narrow-band incoherent light into a Fabry-Perot laser diode (F-P LD). After injection of narrow-band incoherent light, the output of F-P LD becomes wavelength-selective rather than multi-mode and the output wavelength of F-P LD coincide with the peak wavelength of the injected incoherent light. Multi-channel WDM light sources according to the present invention can be implemented using a single broadband incoherent light source and plurality of F-P LDs. An optical transmission system for upstream signal transmission in an passive optical network using the light source according the present invention is also disclosed.

A system access method of a narrowband terminal is provided for supporting both wideband and narrowband terminals in a cellular radio communication system. The method includes broadcasting a Shared CHannel (SCH) for a terminal to acquire system synchronization; transmitting a Low-end Master Information Block (L-MIB) including control information on an L-subframe configuration for supporting a second type terminal and a sub-band configuration of the L-subframe; transmitting a Low-end System Information Block (L-SIB) including information on downlink reception and uplink transmission of the second type terminal; and performing a random access procedure, when an attach request is received from one of the first type terminals and the second type terminals.

To address the scarcity of radio frequency (RF) spectrum, the disclosed systems offer unique ways to mitigate interference between television broadcasters (including their direct audience and viewers served via cable television) and other concurrent users of the RF spectrum, e.g. for one-way or two-way wireless communication. A preferred embodiment makes use of the “framing” characteristics of the “letterbox” video display format. RF emissions of the simultaneous RF spectrum user are keyed “on” only or substantially only during the time intervals when the blanking intervals and/or letterbox-border video lines are being scanned on the display, i.e. when the potentially affected (interfered with) television display is in the letterbox-frame-scanning portions of each video field. The concurrent uses may support services for voice (including telephony, music etc.), data (including Internet, intranet, etc.); image or control; fixed, portable, mobile or nomadic; narrowband, broadband or ultra-wideband; radiodetermination, diathermy, etc. Additionally, the concurrent user's emitted power and receiver sensitivity is continuously adjusted according to the broadcast television signal.

A system for direct injection of selected thermal-infrared (IR) wavelength radiation or energy into food items for a wide range of processing purposes is provided. These purposes may include heating, raising or maintaining the temperature of the food articles. The system is especially applicable to operations that require or benefit from the ability to irradiate at specifically selected wavelengths or to pulse or inject the radiation. The system is particularly advantageous when functioning at higher speeds and in a non-contact environment with the target.

The device and method of the invention receives a digital speech signal, which is processed by an Acoustic Processor to produce a Mel-Cepstrum Vector and Pitch. This is recalibrated and encoded. The encoded signal is transmitted over a narrow-band Channel, then decoded, split and recalibrated. From the split signals, one signal feeds a Statistical Processor which produces Recognized Text. Another signal feeds a Regenerator, which produces Regenerated Speech. The device and method according to the invention achieve simultaneously very perceptive Automatic Speech Recognition and high quality VoCoding, using Speech communicated or stored via a Channel with narrow-bandwidth; very perceptive Automatic Speech Recognition on a Client & Server system without a need to store or to communicate wide-bandwidth Speech signals; very perceptive Automatic Speech Recognition with Deferred Review and Editing without storage of wide-bandwidth Speech signals; better feedback in a system for Automatic Speech Recognition particularly for Deferred Automatic Speech Recognition; and good usability for unified Automatic Speech Recognition and VoCoding.

A narrowband communication system provides wideband data services in a secondary service band. This limits the impact on primary services in peak traffic regions in that the primary service band is not required to download wideband data from a communication node (e.g., a satellite) to a mobile terminal. The narrowband communication system implements a handoff protocol (400) that rate negotiates a channel bandwidth of an active connection (404) to the amount of channels that are available in a new cell. The narrowband communication system preempts (414) lower priority subscribers when a higher priority (408) high-speed data terminal requires access to the system and a requested channel assignment is not available (412). The complexity of a high-speed data terminal communication chipset is reduced by a receiver design that minimizes the range of frequencies that are required to be demodulated.

A wireless communication device is implemented to include a communication interface and a processor. The processor is configured to process communications associated with the other wireless communication devices within the wireless communication system to determine one or more traffic characteristics of those communications as well as one or more class characteristics of the other wireless communication devices. The processor is configured to classify the communications into one or more access categories based on the one or more traffic characteristics and is configured to classify the other devices into one or more device class categories based on the one or more class characteristics. The processor is then configured to generate one or more channel access control signals based on these classifications. The communication interface of the device is configured to transmit the one or more channel access control signals to one or more of the other devices.

A wireless spread spectrum communication system for transmitting data includes a plurality of end point transmitters and at least one receiver. The end point transmitters transmit data via a frequency hopped spread spectrum signal where the transmitting signal is sent without the benefit of frequency stabilization. The receiver is responsive to the frequency hopping spread spectrum signals and includes a correlator and a signal processor. The correlator samples at least a first portion of a preamble of the signal and correlates the portion of the preamble with a known preamble pattern to determine a probability of correlation. The signal processor applies a Fast Fourier Transform algorithm to the signal in response to the probability of correlation to track a narrowband frequency of the signal based on at least a second portion of the preamble and to decode data encoded within the signal subsequent to the preamble.

The present invention centers upon uplink communication protocols for use primarily with orthogonal frequency division multiple access (OFDMA) communication systems. Aspects of the invention relate to narrow band frequency division multiplexed (NBFDM) modulation protocols primarily for uplink usage in asymmetric OFDMA communication systems. In particular, NBFDM uplinks that use quadrature multiplexed continuous phase modulation are detailed and noncoherent detection schemes are developed to process the uplink channel signals without the need to transmit uplink phase reference signals. Other aspects of the invention relate to burst mode uplink communications in OFDMA systems such as those involving opportunistic beamforming.